opatent.com · 2019. 5. 30. · steven c. oppenheimer, esq. patent attorney (pto reg. # 57,418, md...

Steven C. Oppenheimer, Esq. Patent Attorney

(PTO Reg. # 57,418, MD Attorney # 1706200135) 12207 Braxfield Court www.OPatent.com Suite 15 [email protected] Rockville, MD 20852 (301) 468-9233 (h/o) / (240) 678-7422 (c)

Patent samples, Mechanical and Electromechanical. Five patent writing samples follow:

• Eye Scanner With Integrated Focus Distance Determination Mechanism, U.S. 2009/0092292 Carver, et al. ............................... 2 A hand-held iris scanner has a visor connected to it via a hinge. The visor can be folded and locked into an extended position, so the free-floating end of the visor provides a contoured surface against which a user may place his or her forehead. The visor may also be folded and locked into a second position for compact storage.

• Small Caliber Implantable Biometric Leads and Cables for Same,

U.S. 8,108,053, Zhao .,,,,..................................................................26 Conducting filaments within an implantable medical leads have oval cross-sections. Suitably orienting the oval filaments distributes the pressure and reduces fretting fatigue, and also increases conductivity.

• Customizable Mechanically Programmable RFID Tags, U.S. 7,876,222, Calvarese ...............................................................73Tearable strips are attached to the tag, each strip having an electrical conductor. Each tearable strip has a visual or tactile indicia, such as text, a color code, a graphic symbol to assign a meaning to the strip, where the meaning is associated with the status or condition of the item.... By tearing some strips or all strips, a desired bit pattern may be programmed into a register of the RFID tag.

• Simulation Arena Entity Tracking System, U.S. 2007/0152157, Page ............................................................................................... 107In a large-scale simulation arena where people engage in gaming exercises, this system and method tracks the motion of people and objects. The application involves both novel hardware elements and software processing.

• Identifying RFID Tag Moving Coherently With Reader, U.S. 7,619,524, Calvarese .............................................................. 133 A system and method used in warehouses with moving inventory, where the objects have RFID tags attached. The system attaches RFID readers to forklifts and other item carriers. The system distinguishes between items/tags that are moving coherently with an RFID reader—and so are moving with the forklifts—from items/tags that are stationary.

111111 1111111111111111111111111111111111111111111111111111111111111111111111111111 US 20090092292Al

(19) United States c12) Patent Application Publication

CARVER et al. (10) Pub. No.: US 2009/0092292 Al (43) Pub. Date: Apr. 9, 2009

(54) EYE SCANNER WITH INTEGRATED FOCUS DISTANCE DETERMINATION MECHANISM

(76) Inventors: John F. CARVER, Palm City, FL (US); George William McClurg, Jensen Beach, FL (US); Adam Mark Will, Boynton Beach, FL (US); Douglas S. Hodges, Boynton Beach, FL (US); Dean John Fedele, Jupiter, FL (US)

Correspondence Address: STERNE, KESSLER, GOLDSTEIN & FOX P.L. L.C. 1100 NEW YORK AVENUE, N.W. WASHINGTON, DC 20005 (US)

(21) Appl. No.: 11/868,403

(22) Filed: Oct. 5, 2007

Publication Classification

(51) Int. Cl. G06K 9100 (2006.01)

(52) U.S. Cl. ........................................................ 382/117

(57) ABSTRACT

A hand-held iris scanner, used for identifYing individuals, has a visor mechanism connected to the main body of the scanner via a hinged attachment. The visor mechanism can be folded and locked into an extended position, wherein the free-floating end of the visor (that is, the non-hinged end) provides a contoured surface against which a user may place his or her forehead. By placing the forehead against the visor, the user automatically positions their eyes within a field of view of the scanner optics, and at a substantially optimum distance for correctly focused imaging by the scanner optical system. The visor mechanism may also be folded and locked into a second position wherein the bulk of the visor is substantially flush with the main body of the scanner, allowing for compact storage. An optional cap attachment on the visor provides a cover mechanism to protect the scanner optics when the scanner is not in use.

Steven Oppenheimer Patent Writing Samples: Mechanical and ElectroMechanical Page 1

Patent Application Publication Apr. 9, 2009 Sheet 1 of 12

~I

US 2009/0092292 A1

0 ..... .....

. (!) -LL



~I

US 2009/0092292 Al

0 N

. C) -u.


Patent Application Publication Apr. 9, 2009 Sheet 3 of 12 US 2009/0092292 Al

110

200

f?l~~ii;-~~.~~~ 250 ! 250

210 210

-;/ 230 205

FIG. 2



0 0 N

US 2009/0092292 Al

0 N ....-

. (!) -u.



0


Patent Application Publication

1.0 0 1.0

Apr. 9, 2009 Sheet 6 of 12

0 0 N

US 2009/0092292 Al

0 N v

Lt')

• (!) -u.



il

200

\ I

....

~~ <C <0

0 . I N (!) co I -'

~ LL

0\ (")\

0 co \ N \ co

\

' 'lt



~I

• CJ -L1.



710 200

CLOSE OPEN

720

CLOSE OPEN

730

CLOSE OPEN

740

FIG. 7



0 ..--N

Apr. 9, 2009 Sheet 10 of 12

0 0 N

US 2009/0092292 A1

ctl !tl 0 0 (")

00

<( co . (!) -LL.



/

I I

I /

/ /

/

Apr. 9, 2009 Sheet 11 of 12

/ /

/ I

/ I

/ /

FIG. 88

/

/ /

/

/ /

/ /

/

/ /

/

US 2009/0092292 Al

/ /

/ /

/

~

810a

830a

110



0

""" N

0 ..--N

Apr. 9, 2009 Sheet 12 of 12 US 2009/0092292 A1

. " -u.


US 2009/0092292 AI

EYE SCANNER WITH INTEGRATED FOCUS DISTANCE DETERMINATION MECHANISM

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention [0002] The present invention relates generally to the field of biometrics. The present invention relates more particularly to scanning devices used to identifY persons or other living beings based on biometrics associated with the eye. [0003] 2. Background Art [0004] Biometrics is a science involving the analysis of biological characteristics. Biometric imaging captures a measurable characteristic of a human being or other living organism, typically a mammal, for identity purposes. See, for example, Gary Roethenbaugh, Biometrics Explained, International Computer Security Association, Inc. (1998), pp. 1-34, which is incorporated herein by reference in its entirety. [0005] Eye scanners are biometric imaging systems for acquiring images of the human eye or the eye of other mammals for identity purposes. Two common types of eye scanners are iris scanners and retinal scanners, each of which rely on the distinctive patterns of the human iris or retina, respectively, to distinguish one individual from another. [0006] Optical elements of eye scanners need to be correctly aimed at the eye or eyes of a user, and further the optical elements need to be focused correctly on the physiological features of interest (such as the iris of the eye, the retina of the eye, etc.) to obtain quality images of these features. Additional requirements for effective scanning include ensuring that the eyes are shielded from ambient light which may interfere with effective image capture; and at the same time aligning the eyes of the user with illumination from the scanner, which is intended to illuminate the eyes for purposes of image capture. [0007] Ensuring correct focus of an eye scanner on the physiological features of interest, and further insuring correct alignment, may involve correct translational positioning of optical components relative to an eye along a line of sight from the eye. If may further involve ensuring that the optical components are at a correct height relative to the eye or eyes of a user. [0008] For example, one approach to a sensing system may employ variable optical elements, e.g., a mechanical focusing mechanism, which may in turn entail gears, rails, springs, internal hydraulics, or similar elements. Such mechanical focusing mechanisms based on translational movement may move or otherwise adjust lenses or other optics to move closer or further from an eye along the line of sight of the eye to bring to bring features of interest to an in-focus condition. However, such focusing mechanisms introduce substantial mechanical complexity, along with a requirement that a determination be made via some means or mechanism to ascertain when the desired physiologic features of the eye are actually in focus. Such translational movement of optics further-from and closer-to the eye may also be cumbersome and undesirable for users. [0009] Another possible means of focusing and alignment is to enable the person being measured to move their head in relation to the scanning mechanism, until the eye is in the proper position for a good focus. However, this approach may require a dynamic determination to be made as to when the person's eyes are at the proper distance from the scanning device, or at the proper height or correct angle relative to the scanner device. A further requirement is to provide visual

1 Apr. 9, 2009

indicators which signal to a person that he or she should move the head forward or backwards or in other directions, or keep the head at the current location. [0010] Again, however, design complexity ensues; moreover such a system may also pose a challenge for some users who have difficulty following the visual cues which are intended to guide the position of their eyes or head. Such movement of a person closer to or further from an eye scanner may be awkward in many applications such as remote field use for hostile environments. [0011] What is needed, then, is a mechanically and electrically simple means to ensure that a person's head, and in particular a person's eyes, are properly positioned in relation to an optical sensor in terms of distance and other related location vectors, in order to ensure proper focus by the sensor optics on the physiologic features of a person's eyes, with minimal scanner system complexity. What is further needed is a system which aligns the eyes of the user with scannergenerated lighting, while shielding the eyes from unwanted ambient lighting. What is further needed is a system and method which is simple, whose usage is straightforward for a typical or average user, and which is convenient for the user whose eyes are to be imaged via the optical scanning system.

BRIEF SUMMARY OF THE INVENTION

[0012] The present invention solves the above-mentioned needs by providing an eye scanner with an attached visor. One end of the visor is attached to the main body of the scanner. The other end of the visor is contoured in shape so that the forehead of a person tends to fit into the contour of the visor. A person may place their forehead flush against the contoured end of the visor, and consequently the person's head and eyes may be in a position for measurements to be made of their eyes. In particular, the person's eyes may be within a field of view of the optical element of the scanner to allow the optical element to obtain an image of at least a portion of the eye. [0013] In a further embodiment, the visor mechanism may be toggled into at least two different locked or fixed positions. In at least one of these fixed positions, the visor extends from the main body of the eye scanner in such a manner that a person may place their forehead against the free-floating end of the visor, and consequently be looking into the exterior optical elements of the scanner. The other fixed position may be a storage position of the visor. [0014] Further embodiments, features, and advantages of the present invention, as well as the structure and operation of the various embodiments of the present invention, are described in detail below with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES

[0015] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention. [0016] In the drawings, like reference numbers indicate identical or functionally similar elements. Further, and except where specifically noted otherwise, the drawing in which an element first appears is typically indicated by the leftmost


US 2009/0092292 AI

digit(s) in the corresponding reference number (e.g., an element numbered 302 first appears in FIG. 3). [0017] FIG. 1A is a drawing of a first view of an exemplary iris scanner showing some of the exterior elements, where the iris scanner does not have a visor. [001S] FIG. 1B is a drawing of a second view of an exemplary iris scanner showing some of the optical and illumination elements of the scanner, where the iris scanner does not have a visor. [0019] FIG. 2 is a drawing of a first view of an exemplary iris scanner, where the iris scanner has an exemplary visor. [0020] FIG. 3 is a drawing of a second view of an exemplary iris scanner, where the iris scanner has an exemplary visor. [0021] FIG. 4 is a drawing of a third view of an exemplary iris scanner, where the iris scanner has an exemplary visor. [0022] FIG. 5 is a drawing of a fourth view of an exemplary iris scanner, where the iris scanner has an exemplary visor. [0023] FIG. 6A is a drawing of an exemplary iris scanner with an exemplary scanner visor extended into a open position, and with the head of an exemplary user of the scanner positioned at a distance from the scanner which is not the correct distance for optimum scanning. [0024] FIG. 6B is a drawing of an exemplary iris scanner with an exemplary scanner visor extended into a open position, and with the head of an exemplary user of the scanner properly positioned against an exemplary forehead receiving edge of the visor. [0025] FIG. 7 is a series of images representing an exemplary visor being folded from an open position to a closed position, or vice-versa. [0026] FIG. Sa is an exploded view of exemplary hinges connecting an exemplary iris scanner visor to an exemplary iris scanner housing. [0027] FIG. Sb is a detailed view of an exemplary joint of an exemplary hinge component on an exemplary iris scanner housing. [002S] FIG. 9 is an exploded view of an exemplary hinge joining an exemplary visor cap with an exemplary iris scanner VISOr.

[0029] The features, objects, and advantages of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings in which like reference characters identifY corresponding elements throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawings in which an element first appears is indicated by the leftmost digit(s) in the corresponding reference number.

DETAILED DESCRIPTION OF EMBODIMENTS

[0030] [0031] [0032] [0033] [0034] [0035] [0036] [0037]

I. Overview II. Exemplary Scanner III. Exemplary Scanner With Visor IV. Exemplary Usage V. Exemplary Joints and Hinges VI. Exemplary Visor Cap Hinge VII. Further Embodiments VIII. Conclusion

I. Overview

[003S] Embodiments of the present invention provide a scanner suitable for scanning the eye or eyes of a person. A suitable, approximately fixed relative position between the

2 Apr. 9, 2009

scanner optics and the person's eyes, as well as a suitable orientation between the scanner and the person's head, may be established by means of a rigid or substantially rigid visor which extends from the main body of the scanner. In particular, a suitable distance between the scanner optics and the person's eyes may be established by means of the rigid or substantially rigid visor which extends from the main body of the scanner. The suitable position, orientation, and/or distance of the person's eye or eyes and head in relation to the scanner optics ensures that at least a portion of the person's eye or eyes are within the field of view of the scanner optics. This enables the scanner optics to obtain an image of at least a portion of the person's eye or eyes. [0039] Exemplary embodiments are described in terms of exemplary iris scanners, which may be used for identifying persons based on features of a person's iris. However, the present invention may equally well be employed in the context of other eye scanning devices which may scan, for example and without limitation, the human retina or the pattern of blood vessels of the choroid (which may be visible through the sclera). [0040] Embodiments illustrated herein may be portable eye scanners, and may further be handheld eye scanners, but the present invention is not limited to such devices. It will be apparent to persons skilled in the relevant arts that the present system and method may apply equally to non-portable eye scanners and to eye scanners which are held in place in relation to a person's head and/or eyes by means other than being held in the person's hands. [0041] For brevity, this document sometimes uses the singular term "eye", or the plural term "eyes", where it may be understood that either the singular term "eye", the plural term "eyes", or both may be applicable, depending on particular configurations of particular embodiments of the present invention. [0042] For purposes of background information, FIG. 1A and FIG. 1B pertain to illustrating elements of an exemplary 1ns scanner. [0043] FIG. 2 through FIG. 9 pertain to illustrating aspects of exemplary embodiments of the present invention. In particular, FIG. 2 through FIG. 5 pertain to illustrating elements and features of an exemplary iris scanner with a visor. FIG. 6A, FIG. 6B, and FIG. 7 pertain to illustrating an exemplary usage of an exemplary iris scanner by an exemplary user, and to illustrating how an exemplary visor of an exemplary iris scanner may be opened and closed. FIG. SA, FIG. SB, and FIG. 9 pertain to illustrating exemplary hinge and joint elements and an exemplary cap of an exemplary scanner with VISOr.

II. Exemplary Scanner

[0044] FIG. 1A is a drawing of a view of an exemplary iris scanner 100 showing some of the exterior elements, where the iris scanner does not have a visor. Scanner 100 may include a main scanner outer casing 110, which may also be referred to synonymously as the scanner main housing 110, the main scanner body 110, or simply as scanner housing 110. Scanner housing 110 may be used by a person to hold the scanner. Scanner housing 110 may also contain internally, and be used to internally anchor or fix in place, some or all of the main functional elements of scanner 100. [0045] In one embodiment of the present system and method, scanner housing 110 may be approximately cuboid in shape (that is, having a shape which is approximately a


US 2009/0092292 AI

rectangular parallelepiped), with three pairs of facing, approximately planar surfaces, defining a substantially closed scanner housing 110, wherein for any given pair of facing planar surfaces a first planar surface of the pair may be substantially or approximately parallel to a second approximately planar surface of the same given pair. Each pair of the three pairs of facing approximately planar surfaces may be substantially or approximately orthogonal to each of the other two pairs of facing approximately planar surfaces. [0046] In alternative embodiments of the present system and method, scanner housing 110 may have other shapes including, for example and without limitation, approximately ellipsoid, approximately triangular, approximately cylindrical, and approximately pyramidal. Other shapes are possible as well within the scope and spirit of the present system and method. While scanner housing 110 is discussed and illustrated throughout this document as having an approximately cuboid shape for purposes of presenting embodiments of the present system and method, scanner housing 110 is not limited to an approximately cuboid shape. [0047] Scanner 100 may have a front 105 or front side 105, where front 105 may typically be a side of scanner 100 which is configured to admit light to optics and/or imaging elements (described further below) for use in obtaining an image of at least a portion of an eye. It may therefore be desirable, when scanner 100 is in use, that a user position their eyes to be within a field of view of scanner 100 optics by positioning their eyes to be looking into front 105 of scanner 100. (In conjunction with this, see also FIG. 6A and FIG. 6B and related discussion, below.) [0048] Scanner 100 may have a translucent (that is, clear) or semi translucent covering (not illustrated) over front side 105. Such a covering may be composed of a material or materials such as glass, Plexiglas, plastic, or other translucent or semitranslucent materials. Such a covering may serve to provide protection to interior optics or imaging elements, interior illumination elements, and other interior components of scanner 100, while still permitting the passage of light in one or both directions through the covering. In addition to the covering, a seal or sealing material (not illustrated) bonding the cover to housing 110 may provide additional protection for the interior environment of scanner 100. [0049] Further details of internal structures, features, and/ or operations of scanner 100 are discussed throughout this application, and in particular in the discussion immediately below related to FIG. 1B and in the section below entitled "VII. Further Embodiments." [0050] FIG. 1B is another drawing of a view of an exemplary iris scanner 100 showing some of the scanner elements, where the iris scanner does not have a visor. In particular, FIG. 1B is a view which may be seen by a user whose eyes are at a level with scanner 100, and who is looking directly into front side 105 of scanner 100. Not shown or suggested by FIG. 1B is the translucent or semitranslucent covering and possible associated seal which may be present at front side 105 of scanner 100, as already discussed above. [0051] Exemplary iris scanner 100 may include, for example situated within front side 105, a means for accepting an image of at least a portion of the human eye into the scanner. Such means may include, for example and without limitation, a simple opening which admits light which may be seen by interior optics of scanner 100, and lens or lenses 120 which may focus or help focus an image of the eye or eyes on an internal imaging element (not illustrated) contained within

3 Apr. 9, 2009

housing 110 of scanner 100. Exemplary iris scanner 100 may also provide illumination 130 which may be used for such purposes as illuminating the eye of a user, contracting the pupil or an eye of a user (and thereby enlarging the area of the iris available for imaging), or guiding the direction of sight of the eye of a user. [0052] Illumination 130 may be direct illumination provided by a light bulb, laser light, LED, or similar light source. Illumination 130 may also be in the form of a diffuse illumination, whereby a means (not illustrated) of dispersing light is employed so that the source of illumination is not directly visible to a user of scanner 100. For example, a frosted piece of glass or plastic may be placed between a source of illumination and the eyes of the user, ensuring that the light which reaches the users eyes of diffused or softened. Other means to soften or diffuse the scanner illumination may be employed as well. This may make it possible to provide effective illumination for scanning the eyes of the user, while not drawing the user's line of sight directly to the source of illumination. It may be preferred, for example, that the user's line of sight is directed to the imaging optics, rather than the source of illumination. [0053] It is to be understood, then, that at least some optical elements 120 and/or illumination elements 130 of scanner 100 as seen through front side 105 may be visible to a user of scanner 100, and may further directly receive light from the outside or directly transmit light to the outside to illuminate the eyes of a user. In this specific sense, such optics 120 and illumination 130 may be described herein as "exterior optics 120" or "exterior illumination 130". [0054] At the same time, there may be a translucent covering or semitranslucent covering over front side 105, as described above, and optics 120 and illumination 130 may be interior to scanner housing 110 in relation to such a cover. Further, optics 120 and illumination 130 may be recessed within scanner housing 110. Consequently, it is to be understood that while the terms "exterior optics 120" and "exterior illumination 130" may be employed herein for descriptive purposes as indicated above, optics 120 and illumination 130 may be structurally interior to scanner 100. [0055] It is to be further understood that scanner 100 may employ additional optics and/or imaging systems, and possibly additional internal sources of illumination, which are not directly visible through front side 105, and which may receive or transmit light from the outside only indirectly (for example, via mirrors, lenses, prisms, fiber optics, or other elements which direct light along an interior path). Such elements may be referred to as "interior optics" or "interior illumination". Where the terms "optics", "optical systems", "illumination", "illumination elements" and similar terms are used without reference to "interior" or "exterior", it will be apparent from context if the terms indicate exterior elements (as characterized above), interior elements, or possibly may indicate either interior elements, exterior elements, or both. [0056] Exemplary iris scanner 100 may require that, in order to accurately identify a person based on characteristics of an iris or irises, the optical systems and/or imaging systems within scanner 100 should be able to obtain a substantially focused image of an iris or both irises of the person. It may also be necessary for the eye or eye's of the user to be properly aligned in relation to illumination elements. In turn, it may be necessary both that the person's eyes be within a field of view of scanner 100, and that the distance between the person's eyes and the exterior-most lenses 120 or other exterior optics


US 2009/0092292 AI

120 or light entry means of scanner 100 fall within a fairly narrow range, with that range centered around a specific, optimum distance. In particular, this may require that a person who is using scanner 100 position their eyes to be looking into front 105 of scanner 100, and further that the person have their eyes positioned at a suitable distance from front 105 of scanner 100. It may also be necessary that scanner 100 be at a suitable height relative to the eyes of a user, and that scanner 100 be suitable oriented in other respects in relation to the eyes and/or head of a user.

[0057] Put another way, for optimal scanning, and in particular for reliable and consistent biometric identification, it may be that the eyes of the person should be within a field of view of scanner 100, and in particular within a field of view of the optical system. In one example, an eye or eyes are positioned within a field of view at a distance that allows an image of at least a portion of an eye to be obtained by an optical system in scanner 100. For example, the eye position may be located at a distance corresponding to an "in-focus" condition, where the eye position is imaged by the optical system at a correct focal length.

[0058] Persons skilled in the relevant art(s) will appreciate that this "in-focus" distance may, in some embodiments, be on the order of a length of the scanner itself-for example, half the length of the scanner, or two-thirds of the length of the scanner, with the precise distance depending on the configuration of the optics and imaging elements housed within scanner housing 110. [0059] Persons skilled in the relevant art(s) will further appreciate that, in terms of the distance of a person's eyes from the scanner when the scanner is in use, there may be some allowable minor variation in either direction from this substantially fixed optimal distance. Such allowance for small variations in distance may be necessary in the design of scanner 100 due to the fact that the eyes of different people may have a slightly different depth in relation to their foreheads, and possibly due to other physiological factors, and factors of other kinds.

[0060] Due to the lack of a visor on exemplary scanner 100, it may be difficult for a person using the scanner to place their eyes at the required distance from the exterior optics 120 of the scanner. Moreover, due to the lack of the visor, it may be difficult to align the person's eyes with the scanner optics 120, or to align the person's eyes with the scanner illumination 130, or both. Moreover, due to the lack of the visor, it may be difficult to shield both the person's eyes and the optical system of scanner 100 from ambient lighting. Finally, due to the lack of a visor and possibly an associated cap, it may be difficult to protect the scanner optics from degrading environmental factors such as moisture or dust when scanner 100 is not in use.

III. Exemplary Scanner with Visor

[0061] The following discussion discloses one or more embodiments of an exemplary iris scanner 200 consisting of an exemplary visor, which may also be referred to as a hood, which may be attached to an exemplary iris scanner housing 110 for multiple functional purposes including, for example and without limitation:

[0062] orientating a user's head and eyes so that the person's eyes are within a field of view of optics 120 of scanner 200, so that scanner 200 may obtain an image of at least a portion of an eye of the user;

4 Apr. 9, 2009

[0063] establishing an appropriate distance between the eyes of the user and the scanner optics 120 and/or imaging system(s);

[0064] establishing a correct orientation between the eye or eyes of a user and the scanner optics 120 and/or imaging systems;

[0065] aligning the eye or eyes of a user with the scanner illumination element or elements 130, so that the eyes receive sufficient illumination to be imaged by the scanner optics 120; and

[0066] shielding either the human or the scanner 200, or both, from ambient lighting.

[0067] The discussion may disclose a visor configured for use with an iris scanner housing 110 which is substantially or approximately cuboid, as with scanner 100 discussed above in conjunction with FIG. lA and FIG. lB. However, persons skilled in the relevant arts will appreciate that a visor may be configured consistent with the present system and method which may be employed in conjunction with a main scanner body which may have a shape substantially different from a cuboid shape, while still enabling one or more of the functional purposes enumerated immediately above. [0068] FIG. 2 shows a view 200(a) of an exemplary iris scanner 200. Iris scanner 200 includes housing 110. Housing 110 plus all components internal to housing 110, and further including any components embedded within scanner housing 110 (including, for example, various ports and connectors), but apart from a visor 210 which may be attached to housing 110, may comprise a main body of scanner 200. [0069] Exemplary scanner 200 may be the same, substantially the same, or similar to exemplary iris scanner 100 (discussed above in conjunction withFIG.lA and FIG.lB) in terms of housing 110 and in terms of internal structure, function, and operations. Therefore, a discussion of housing 110 and the internal structural and functional features of exemplary iris scanner 200 which are analogous to those of exemplary scanner 100 will not be repeated here. However, exemplary iris scanner 200 may have an attached exemplary visor 210. [0070] Exemplary iris scanner 200 may have a side which may be referred to as the top side, and which is the side of scanner 200 which would normally face the ceiling or sky when scanner 200 is held as it may be held for normal usage by a person standing upright. View 200( a) presents a top view of scanner 200, showing the top side of scanner 200, with exemplary visor 210 fully extended from scanner housing 110, a position that may also be referred to as the open position of visor 210. [0071] The surface shown of exemplary visor 210 may be a top surface 205, which may help shield both the eyes of a user and the scanner optical elements 120 and lighting elements 130 from ambient lighting. Visor 210 may be viewed as serving both as a shield or shade from ambient lighting, and as a positioner or positioning element to properly position the head of a user in relation to scanner housing 110. [0072] In embodiments illustrated throughout this document, visor 210 does not have a bottom side. Consequently, and in relation to such embodiments, the discussion here and elsewhere in this document of the application of exemplary visor 210 as a light shield typically assumes that ambient lighting comes from the sky, ceiling lights, or other light sources which are situated no lower than the height of the head of a person using scanner 200, as is typically the case. Visor 210 without a bottom side may not be effective or may


US 2009/0092292 AI

be less effective at shielding against ambient light if the ambient light comes from a source which is at or below the height at which scanner 200 is itself used, which may be the same height as the height of the eyes of a user. [0073] In an alternative embodiment of the present system and method, visor 210 may have a bottom side (not illustrated). Such embodiments are described further in the section of this document entitled "Section VII. Further Embodiments". [007 4] Exemplary visor 210 may be joined to scanner housing 110 via joints 250 on either side of scanner housing 110, where the structural elements of joints 250 (discussed further below) may be partly hidden from view underneath the side panels of visor 210. A near end of visor 210, that is, the end closest to scanner housing 110, may be attached to the front side 105 of scanner housing 110, which contains exterior optical elements 120 (not visible in this view) which can accept within their field of view an image of a person's eye or eyes, as well as exterior illumination elements 130 (also not visible in this view) which illuminate the person's eye or eyes. [0075] At the far end or distal end of visor 210, that is, the end most distant from scanner housing 110, visor 210 may be contoured with a curved contour 230 which substantially conforms to the curve of a forehead of a typical person. In this way, a typical person may place their forehead flush against contour 230 of visor 210, and in so doing may place their eyes within the field of view of scanner optical elements 120. Further, in placing their forehead flush against contour 230 of visor 210, the person may place their eyes at a distance from optical elements 120 which falls at or near the optimal range for scanning of the eyes by scanner 200. [0076] Further, in placing their forehead flush against contour 230 of visor 210, the person may place their eyes so that their eyes are aligned in a substantially optimal position in relation to scanner illumination elements 130. In some embodiments of the present system and method, optimal aligmnent may be further achieved by indicating to a user a preferred height at which contour 230 of visor 210 should be placed, for example, immediately above the eyebrows, or approximately one inch above the eyebrows, etc. There may also exist a preferred angle at which the visor 210 and scanner 200 should be placed, for example, approximately level relative to the ground (assuming the user is sitting or standing upright). Other angles may be preferred instead. [0077] Scanner 200 may also include a cap 240 which is attached to visor 210. Cap 240 may be an elongated element with a length and width substantially the same as the length and width of a side of scanner housing 110 which may be protected or covered by cap 240. Cap 240 may be flat, or may have a bulge or curvature creating a depth for cap 240. When visor 210 is in the open position, cap 240 may rest on a surface of scanner housing 110, which may for example be the top surface, where cap 240 does not hinder either scanner 200 operations or the activity of the user. Visor cap 240 may be attached to visor 210 via a visor cap hinge 260 which may be a spring-loaded visor cap hinge 260. [0078] Both scanner housing 110 and visor 210 may be composed of a material or combination of materials such as plastic, various metals or metal alloys, various polymers, or various composite substances well known in the art. Such materials may be rigid enough to provide the necessary structural sturdiness for scanner housing 110 and visor 210 to operate properly (for example, to provide support for internal structural and functional components, or to establish a sub-

5 Apr. 9, 2009

stantially fixed distance between the forehead of a user and the optical elements of the scanner); yet such materials may also have sufficient ability to bend or flex, that is, may have a sufficient elasticity, to support the operation of moving elements such as scanner body/visor joints 250. [0079] The points of attachment of visor 210 to scanner housing 110, and in particular the location of joints 250, may be at the front 105 of scanner housing 110, where the front of scanner housing 110 may be defined, as per the discussion above, as being the side of scanner housing 110 where the exterior optics 120 and exterior illumination 130 of scanner 200 are located. [0080] FIG. 3 shows a second view 200(b) of exemplary iris scanner 200 first seen in FIG. 2. View 200(b) shows exemplary iris scanner 200 from a head-on frontal view. This is a view which may be seen by a user of scanner 200, for example as the user is holding scanner 200 in hand at eye level, and as the user is moving scanner 200 towards their forehead but does not yet have scanner 200 flush against their forehead. [0081] Seen in view 200(b) are the exterior optical or imaging elements 120 and exterior illumination elements 130 of scanner 200 as seen when looking into front 105. Also visible in this view is the front-most rim of visor 210, which may be seen in outline form only. It can be seen that with visor 210 in the open position, as shown, the user may have an unimpeded view of exterior optics 120 of scanner 200, and therefore exterior optics 120 may have an unimpeded view of the user's eyes. Put another way, it can be seen that with visor 210 in the open position, as shown, if the user looks into front 105 of scanner 200, then the eyes or a portion the eyes of the user may fall within a field of view of optics 120 of scanner 200. This enables scanner 200 to obtain an image of the user's eyes for purposes of biometric identification. Similarly, exterior illumination elements 130 may be optimally positioned to illuminate the eye or eyes of the user. Also visible in view 200( b) is the visor cap 240, which may lie flush against the top of scanner housing 110. [0082] FIG. 4 shows a third view 200(c), which may be a side view, of exemplary iris scanner 200, also seen in FIG. 2 and FIG. 3 above. It may be seen that visor cap 240 may lie flush against a side of scanner housing 110, which may be the top side of scanner housing 110 as sensor 200 may be held by a user in normal usage. Visor 210 may have a joint element which may extend to cover part of joint 250 and may itself constitute a part of joint 250. [0083] Visor 210 may have a length 410 which determines the distance between the front 230 of visor 210 and a front side 105 of scanner 200 which displays or reveals optical elements 120 to a user of scanner 200. In one embodiment, it may be that length 410 determines the fixed distance between the eyes of the user and the front 105 of scanner 200 which is the substantially optimal distance for effective and reliable eye scanning by scanner 200. In an alternative embodiment, it may be that length 410, in combination with or in addition with a distance from the front of scanner 200 to exterior optical elements 120, determines the fixed distance between the eyes of the user and optical elements 120 which is the substantially optimal distance for effective and reliable eye scanning by scanner 200. [0084] It may be seen that visor 210 also has a side panel 420 which may extend substantially orthogonally from the top surface 205 of visor 210. Side panel420 may help shield both the eyes of a user and the exterior scanner optical/ lighting elements 120, 130 from ambient lighting. The front


US 2009/0092292 AI

of visor side panel 420 may have a gentle contour 430 designed to match the temples of a human user. [OOS5] FIG. 5 shows a fourth view 200(d) of exemplary iris scanner200, already seen in FIG. 2, FIG. 3, and FIG. 4 above. It may be seen that in the open position, a top surface 205 of visor 210 may be substantially parallel to and substantially co-planar with a top surface 505 of scanner housing 110. This may ensure that when a user whose torso and head are substantially in a vertical position places their forehead against a front edge 230 of visor 210, and assuming the scanner is further held in a substantially horizontal position, the user's eyes are at a correct height to be imaged by scanner 200 and are directed at a correct viewing angle to be imaged by scanner 200. It may also be seen that visor 210 has two side panels 420 which may be approximately or substantially parallel to each other, as well being approximately or substantially orthogonal to top surface 205 of visor 210.

IV. Exemplary Usage

[OOS6] FIG. 6A shows a view 600a of exemplary iris scanner 200 with visor 210 fully extended into the open position, and with the headofa person 610 who is a user of iris scanner 200 positioned at some distance from the forehead receiving edge 230 of visor 210. It may be seen, consistent with the discussion immediately above, that the eyes of person 610 are not at the substantially correct distance from scanner housing 110 for biometric imaging and identification. [OOS7] However, the eyes of person 610 may be within the field of view of exterior optics 120 of scanner 200. Further, the eyes of person 610 are correctly aligned for biometric imaging and identification, in that the head of person 610 is angled at approximately a right angle to an extended axis running from the front of visor 210 through the back of scanner housing 110, the eyes of person 610 are looking into the front 105 of scanner 200, and the eyes of person 610 are level with scanner 200, this shared level being eye level 620. If person 610 were to grasp scanner 200 with their hands (not illustrated), and pull scanner 200 towards their eyes until visor 210 touched their forehead at approximately the midpoint of the forehead, as indicated by dotted line 630, then person 610 would be at a substantially correct distance from the optics of scanner 200 for effective biometric imaging and identification. This is illustrated in the immediately following FIG. 6B. [OOSS] FIG. 6B shows a view 600b of exemplary iris scanner 200 with visor 210 fully extended into the open position, and with the head of person 610 who is a user of iris scanner 200 properly positioned against the forehead receiving edge 230 of visor 210. It may be seen, consistent with the discussion above, that the eyes of person 610 are not only within the field of view of scanner optics 120, but further are now at the substantially correct distance from scanner housing 110 for biometric imaging and identification; and further, that the eyes of person 610 are correctly aligned for biometric imaging and identification. Finally, and assuming ambient lighting comes primarily from a light source which is at a height which is at least as high at the height of scanner 200, but preferably from a height which is somewhat higher than the height of scanner 200, both the eyes of person 610 and the exterior optics 120 of iris scanner 200 are shielded or partially shielded from ambient light by visor 210. [OOS9] FIG. 7 shows a sequence of images 710, 720, 730, and 7 40 which represent visor 210 being progressively folded closed over time, from starting open position 710 to finished

6 Apr. 9, 2009

completely closed position 740. Time series 710-740 illustrates that when visor 210 is in the fully closed position (image 740), visor 210 may be neatly tucked away, flush against a surface which may be a bottom surface of iris scanner housing 110. [0090] It may be further seen from time sequence 710-7 40 that as visor 210 is folded into place under scanner housing 110, visor cap 240 may slide forward off the top surface 505 of scanner housing 110 and into place on the front of scanner housing 110, where visor cap 240 may serve as a cover protecting exterior scanner optics 120. A spring-loaded hinge, discussed further below, serves to hold visor cap 240 flush against top surface 505 of scanner housing 110 when visor210 is in open position 710, and also serves to hold visor cap 240 flush against front 105 of scanner housing 110 when visor 210 is in closed position 740. [0091] Persons skilled in the relevant art(s) will further appreciate that the time series of images of FIG. 7 may equally well represent a reverse direction of motion, that is, a progression from image 740 to 710, in which case visor 210 starts in a closed position 740 and is progressively opened into an open position 710. The opening and closing of visor 210 is made possible by visor joints 250, while the movement of visor cap 240 is made possible by visor cap hinge 260, also discussed further below. [0092] FIG. 7 further illustrates how the relative angle between visor 210 and scanner housing 110 maybe 180° when visor 210 is in fully open position 710, and may be oo when visor 210 is in fully closed position 740, and how the relative angle may also assume intermediate values such as approximately 120° or approximately 60° as visor 210 swings through intermediate positions 720, 730, respectively, in relation to scanner housing 110. As will be discussed further below, some positions, such as fully open position 710 or fully closed position 740 may be positions where visor 210 may be locked into position by user 610, or by a technician (not illustrated) who assists user 610.

V. Exemplary Joints and Hinges

[0093] Exemplary visor 210 may be connected to exemplary iris scanner body 110 via two visor joints, such as exemplary visor joints 250 illustrated in FIG. SA. Visor joints 250 may permit visor 210 to be pivoted through a range of angles in relation to iris scanner housing 110 by the application of a modest torque to visor210. The range of angles may range from a fully closed position, which may be 0 degrees, to a fully open position, which may be 180 degrees, as illustrated in FIG. 7 already discussed above. [0094] In one embodiment, exemplary iris scanner 200 with a visor may consist of two exemplary visor joints 250a, 250b, one each at corresponding positions on each side of iris scanner housing 110. A joint 250 may consist of a hole S1 0 on a side of scanner housing 110, along with a corresponding plug S20 on an interior side of a side panel420 of visor 210. Plug S20 may be a hollow plug, consisting of a raised, substantially circular rim (as illustrated in FIG. SA), or plug S20 may be a solid plug. Each plug S20 is sized so as to substantially conform to and fit within a matching hole S10 on the side of main scanner housing 110. [0095] Holes S10 may be positioned in close proximity to front 105 of scanner housing 110, while plugs S20 are positioned in close proximity to an end of visor 210 which may attach to scanner housing 110. Scanner housing 110 of ex emplary scanner 200 may have extensions or tabs S05 (shown in


US 2009/0092292 AI

FIG. SB), extending forward from scanner housing 110 and providing space for holes SlO as well as notches S30 (discussed further below). [0096] Visor 210 may be constructed so that the distance between plugs S20 is substantially the same as the distance between holes SlO. As a result, plugs S20 may be simultaneously situated within holes SlO, so that a first plug S20a is situated within a first hole Sl Oa on a first side of scanner 200 to create a first joint 250a, at the same time that a second plug S20b situated within a second hole SlOb on a second side of scanner 200 creates a second joint 250b. Note that, due to the particular perspective view in FIG. S, hole SlOb is entirely obscured from view (although its position is suggested by label SlOb), and similarly plug S20a is almost completed obscured from view (although its position is indicated by label S20a ). [0097] Together, the pair of visor joints 250 function as a hinge enabling visor 210 to remain attached to scanner housing 110, and to swing through a range of angles in relation to scanner housing 110 as already described above. [009S] In an alternative embodiment (not illustrated), a visor joint 250 may consist a plug on a side of the main scanner body and a hole on a matching side panel of the visor, where a plug again fits into a hole, and where the placement of the elements is analogous to that described above for the first embodiment. A plug on the scanner body may fit into a hole on the visor, again creating a joint, with the pair of joints creating a hinge between visor 210 and main scanner housing 110. [0099] As previously discussed, scanner housing 110 and visor 210 may be composed of a material or combination of materials which may be rigid enough to provide the necessary structural sturdiness for scanner housing 110 and visor 210 to operate properly; yet such materials may also have sufficient elasticity so as to bend or flex to support the operation of moving elements such as scanner body/visor joints 250. In particular, the materials used to manufacture scanner housing 110 and visor210 maybe elastic enough to allow visor210 to be temporarily flexed slightly at the sides, or possibly to allow scanner housing 110 to be temporarily compressed slightly at the sides, to a sufficient degree that visor 210 may be snapped into place on scanner housing 110 during assembly, and possibly further to allow the remove of visor 210 from scanner housing 110 if desired. At the same time, the construction materials may be sufficiently rigid that once visor joints 250 have been established (for example, by setting corresponding plugs S20a, S20b into corresponding holes SlOa, SlOb, respectively), visor 210 remains attached to scanner housing 110 during the normal course of usage. [0100] Persons skilled in the relevant art(s) will appreciate that the joints 250 described above are exemplary only, and that other joints and/or hinge devices may be used to connect visor 210 with scanner housing 110, and to permit the necessary type and range of relative motion between visor 210 and scanner housing 110, while staying within the scope and spirit of the present invention. [0101] A visor hinge 250 may further consist of a locking element which temporarily locks visor 210 into one of a plurality of fixed angles of connection in relation to the main scanner housing 110. In one embodiment, an exemplary locking element may consist in part of one or more notches S30 on scanner housing 110, where a notch S30 is substantially adjacent to or on the immediate periphery of a visor joint hole Sl 0. An exemplary locking element may further consist in part of

7 Apr. 9, 2009

one or more locking plugs S40 on an interior surface of a side panel420 ofvisor210, where a locking plug S40 is sized to be of a same size as, or a slightly smaller size than, the size of a notch S30. As visor 210 is rotated through various angles in relation to scanner housing 110, one or more locking plugs S40 may become aligned with one or more notches S30. [0102] Due to the elasticity of the materials of scanner housing 110 and/or visor 210, the one or more aligned locking plugs S40 may slide or snap into place within the empty space within the one or more notches S30, effectively locking visor 210 into a fixed angle in relation to visor housing 110. In particular, the notches S30 and locking plugs S40 may be so configured as to ensure that at least two fixed, locked angles may be established, wherein a first fixed, locked angle is the open position of visor 210 and a second fixed, locked angle is the closed position of visor 210 as already described above in conjunction with FIGS. 2, 3, 5, 6, and 7 above. [0103] In exemplary iris scanner 200 illustrated in FIG. SA, a first locking element may consist of notches S30a and locking plugs S40a associated with joint 250a, and a second locking element may consist of notches S30b and locking plugs S40b associated with joint 250b. Note that in FIG. S, locking plugs S40a are entirely obscured from view (although their approximate position is indicated by label S40a ), and similarly notches S30b are obscured from view (although their approximate position is indicated by label S30b ). [0104] While visor 210 may be locked into one or more fixed positions in relation to scanner housing 110, the materials used for construction of visor 210 and/or scanner housing 110 may be sufficiently elastic that the application of a relatively modest degree of torque to visor 210 is sufficient to dislodge locking plugs S40 from notches S30, thereby dislodging visor 210 from a locked position and enabling visor 210 to again rotate freely in relation to scanner housing 110 about joints 250. The relatively modest degree of torque which may be needed to dislodge locking plugs S40 from notches S30 may be an amount of torque which may be within the typical strength of a typical user 610 of scanner 200, and may be applied by user 610 of scanner 200 when user 610 is holding scanner housing 110 in a first hand and gripping visor 210 with a second hand. [0105] In an alternative embodiment (not illustrated), a locking element may consist of one or more locking plugs on a side of the main scanner housing 110 and one or more notches on a matching side panel 420 of visor 210, where a locking plug again fits into a notch, and where the placement of the elements is analogous to that described above for the first embodiment. [0106] Persons skilled in the relevant art(s) will appreciate that the locking elements described above are exemplary only, and that other locking elements or locking devices may be used to temporarily lock visor 210 at a fixed angle in relation to scanner housing 110, while staying within the scope and spirit of the present invention.

VI. Exemplary Visor Cap Hinge

[01 07] Exemplary iris scanner 200 may further consist of a cap 240 attached to visor 210, where when visor 210 is in a closed position, cap 240 may protect the translucent or semitranslucent covering at the front 105 of scanner 200. In embodiments where such a covering is not present, cap 240 may protect exterior optics 120, exterior lighting elements 130, and possibly other exterior elements of scanner 200, and may further help protect both exterior and interior elements of


US 2009/0092292 AI

scanner 200 from environmental elements such as moisture, dirt, etc. Cap 240 has already been discussed in part in conjunction with FIGS. 2 through 5, above. [0108] FIG. 9 provides an exploded view of an exemplary cap hinge 910 which may join cap 240 with visor 210. Cap hinge 910 may consist of a first piano-hinge element 920 on an edge of the visor and a second piano hinge element 930 on an edge of cap 240, where the first piano hinge element 920 and second piano hinge element 930 interlock to form hinge 910. One or more torsional springs 940 may be embedded along the elongated axis of hinge 910, either exterior to or interior to hinge elements 920, 930, with spring 940 configured so that spring 940 presses cap 910 closed over the exterior optics 120 when visor 210 is in a closed position, and so that spring 940 presses cap 240 against a top surface 505 of visor 210 when the visor is in the open position. [0109] Cap 240 may have a gasket along its edge, or scanner housing 110 may have a gasket on its exterior surface substantially aligned with an edge of cap 240, so that when cap 240 covers the front end of scanner housing 110, the gasket provides an additional seal against moisture, dirt, and other environmental elements. [0110] FIG. 9 also illustrates the manner in which visor210 may be joined to housing 110, as indicated by connection lines 250.

VII. Further Embodiments

[0111] In an alternative embodiment consistent with the present system and method, scanner housing 110 may be approximately cuboid in shape; however, one or more surfaces may depart from being substantially planar by being quasiplanar which may entail having an approximately flat surface but varying from being strictly flat by, for example and without limitation:

[0112] having a modest degree of curvature; [0113] having modest indents and/or outdents; [0114] having ridges and/or grooves; [0115] having openings of various sizes; or [0116] having other features which serve either func

tional or ornamental purposes, and which thereby depart from a strictly or substantially planar form.

[0117] In an alternative embodiment consistent with the present system and method, pairs of facing surfaces may be approximately parallel. In an alternative embodiment consistent with the present system and method, at least one of the six outer border planes of the substantially cuboid shape or approximately cuboid shape of scanner 200 may not be a solid surface or substantially closed surface of scanner housing 110. Instead, in one embodiment, at least one outer border plane of scanner 200, which may be a front 105 of scanner 200, may instead be defined by structural or functional elements such as lenses, lighting elements, filters (which may, for example, be clear or tinted plating consisting of glass, plastic, or other polymers or materials), and similar functional elements, wherein such elements may be substantially or approximately coplanar, and so define in part or in whole an exterior boundary of scanner 200. [ 0118] In an alternative embodiment, at least one entire side of the substantially cuboid shape or approximately cuboid shape of scanner 200 may be an open side, possibly a front side 105, which may reveal optical components and other components that are partly or wholly recessed within scanner 200. For example, such an open front side 105 of scanner 200 may reveal lenses, lighting elements, filters, and other imag-

8 Apr. 9, 2009

ing elements which are used to establish a field of view for obtaining an image of at least a portion of an eye of a person for biometric identification, and a person using scanner 200 may look into open front side 105 of scanner 200 during the course of using scanner 200. [0119] As noted above, in an alternative embodiment, exemplary iris scanner 200 may have other shapes. For example, scanner 200 could be substantially oval or round scanner housing 110, with a suitable open front side area 105 for exposing exterior optics 120 and exterior illumination 130. A visor 210 with rounded or curved sides, designed to conform to the shape of scanner housing 110, may be attached to such an exemplary scanner 200 via hinge elements 250 similar to those discussed already above. [0120] Exemplary iris scanner 200 may contain additional elements for accepting, focusing, and processing an image of at least part of an eye of a person, or for otherwise enabling scanner 200 to perform its intended functions. Such elements or components (not illustrated in any of the figures) may be contained within scanner housing 110 or may be behind lens or lenses 120 or behind illumination 130 and may include, for example, and without limitation:

[0121] power delivery and management components (including, for example and without limitation, batteries, transformers, power regulators, and similar components);

[0122] additional optical elements (including, for example and without limitation, lenses, prisms, mirrors, gratings, fiber optics, light-emitting elements, holographic components, and optical filters) for receiving, focusing, steering, filtering, and/or otherwise optically processing an image of the human eye;

[0123] image processing elements (including, for example and without limitation, CCDs, CMOS active pixel sensors, amplifiers, DACs, and ADCs) for transforming an image of at least part of an eye of a person, received by the optical elements, to a signal suitable for image processing;

[0124] signal processing elements (including, for example and without limitation, a DSP, a microprocessor, and/or memory) for identifYing from the obtained signal such physiological features as an iris of a human eye, a retina of the human eye, and possibly other features of the human eye;

[0125] information processing elements for identifYing a person or persons based on the identified physiological features of a human eye; and

[0126] a transmitter or other means to relay information to an external data processing system.

[0127] Scanner 100 may also have additional external features, not illustrated, which enable scanner 100 receive power and/or to communicate data to and/or receive data from an external controller such as a personal computer. Such external features may include, for example and without limitation, one or more power connector( s ), USB port(s ), IEEE 1392 port( s ), Ethernet port( s ), infrared port( s ), serial port( s ), parallel port (s), RJ-11, RJ-14, RJ-25, and RJ-45 connector(s), other modular jack(s), and other ports, jacks, and connectors well known in the art. [0128] In embodiments described above, it has been assumed that exemplary visor 210 of exemplary scanner 200 is opaque, in order to shield the eyes ofuser610 from ambient light. In an alternative embodiment, visor 210 may be composed of a material or materials which are translucent or


US 2009/0092292 AI

semi translucent. In particular, visor 210 may be composed of a material or materials which permit passage of a color of light or colors of light which do not affect the imaging process, while still blocking a color of light or colors of light which would interfere with the imaging process. An advantage of such an embodiment may be that permitting the passage of some ambient light may induce the pupil(s) of the eye( s) of user 610 to close, resulting in a larger area of the iris to be present for imaging. In an alternative embodiment, visor 610 may be translucent or partly translucent to all colors of light.

[0129] Visor 210 has been disclosed above in embodiments with a top surface 205 and two side panels 420, but no bottom. In an alternative embodiment of the present system and method, visor 210 may have a bottom side. With a bottom side component, visor 210 may form an approximately rectangular tube configured to extending from scanner housing 110 to the forehead of user 610. With a bottom side component, visor 210 may be effective in shielding against ambient light which comes from a source which is at or below the height at which scanner 200 is itself used. In one embodiment, a bottom side may be comprised of a detachable panel which may be clipped onto or snapped onto the bottom of side panels 420 of visor 210 when visor 210 is in open position 710.

[0130] In an alternative embodiment, a bottom side may be composed of two semi-flexible elements attached to side panels 420 of visor 210. When visor 210 is in the open position 710, the semi -flexible elements may extend and meet each other to form a bottom side which shields from ambient light coming from below. When visor 210 is returned to closed position 740, such elements may fold into place between visor top 205 and side panels 420, and scanner main body 110. Persons skilled in the relevant arts will recognize that other means may exist to create a bottom side component of visor 210 consistent with the present system and method.

[0131] The present system and method has been disclosed in relation to embodiments where scanner 200 has optical elements 120, illumination elements 130, and possibly other elements suitable for imaging and scanning two eyes of a user. Moreover, visor 210 as disclosed in embodiments throughout this document approximately spans the full width of a person's forehead.

[0132] In an alternative embodiment, scanner 200 may be configured with optical elements 120, illumination elements 130, and possibly other elements suitable for scanning only one eye at a time. In one embodiment, visor 210 may still be configured to span an entire width of a forehead of a person. In an alternative embodiment, visor 210 may be configured to span and to conform to a partial width of a forehead of a person, which may for example be a left side of a forehead, a right side of a forehead, or a center of a forehead.

[0133] The present system and method has been disclosed in relation to embodiments wherein visor 210 has a fixed width, and in particular has a fixed width of an end which is configured to accept a forehead of a person. In an alternative embodiment, visor 210 may be configured with an adjustable width, or may be configured with additional elements to adjust a shape or width of a forehead receiving end to be suitable for foreheads of different persons. For example, visor 210 may be supplied with removable, clip-on attachments which are configured to adjust the size or shape of the fore-

9 Apr. 9, 2009

head receiving end for different users. Other means to adjust the shape or width of the forehead receiving end of visor 210 may be envisioned as well.

VIII. CONCLUSION

[0134] The present invention is not limited to the embodiment of an iris scanner. The present invention can be used with any system that utilizes optics for measuring a physiological property of the human eye, such as a retinal scanner. The previous description of exemplary embodiments is provided to enable any person skilled in the relevant art(s) to make or use the present invention. While the invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the relevant art( s) that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.

1. A scanner for determining the identity of a person, comprising:

a main scanner body; an optical element coupled to main scanner body for

obtaining an image of at least a portion of an eye of the person; and

a visor comprising a first end for attaching to the main scanner body and a second end for receiving a head of the person, the second end of the visor having a substantially fixed relative position in relation to the first end;

wherein the substantially fixed relative position of the second end in relation to the first end determines a relative position between the optical system and the eye of the person whose head is positioned at the visor, such that at least a portion of the eye is located in a field of view of the optical system allowing the optical system to obtain an image of at least a portion of the eye.

2. The scanner of claim 1, wherein the substantially fixed relative position of the second end in relation to the first end comprises a length of the visor between the second end and the first end;

wherein the length of the visor determines a distance between the optical system and the eye of the person whose head is positioned at the visor, such that at least a portion of the eye is located at a focal length of the optical system allowing the optical system to obtain an image of at least a portion of the eye.

3. The scanner of claim 1, wherein the second end of the visor is contoured to substantially conform to a shape of a forehead of the head of the person.

4. The scanner of claim 1, wherein the visor further comprises a first surface extending from the first end to the second end, wherein the first surface is shaped to substantially conform to a surface of the main scanner body.

5. The scanner of claim 4, wherein the main scanner body has a shape which is approximately a cuboid.

6. The scanner of claim 5, wherein the first surface is at least one of substantially flat, substantially planar, and quasiplanar.

7. The scanner of claim 5, wherein a length of the visor between the first end and the second end is at least one of substantially the same length as a length of the surface of the main scanner body and a length on the order of half of the length of the surface of the main scanner body.

8. The scanner of claim 5, wherein the first surface of the visor has a width which is substantially the same as a width of the main scanner body.


US 2009/0092292 AI

9. The scanner of claim 8, wherein the visor further comprises two side panels attached to opposite edges of the first surface of the visor and separated by the width of the visor;

wherein each side panel extends from the first end of the visor to the second end of the visor;

wherein each side panel is approximately parallel to the other side panel;

wherein each side panel extends in a common direction approximately orthogonal to the first surface of the visor; and

wherein the visor with the side panels forms a shroud to shield at least one of the eye of the person and an optical system of the scanner from ambient lighting.

10. The scanner of claim 9, wherein the visor further comprises a bottom element configured to shield from an ambient lighting coming from below the scanner.

11. The scanner of claim 10, wherein the bottom element is configured to be attached to the side panels.

12. The scanner of claim 10, wherein the bottom element is configured to be removable.

13. The scanner of claim 1, further comprising a visor hinge attaching the visor to the main scanner body, wherein the visor hinge permits the visor to be pivoted through a range of angles in relation to the main scanner body.

14. The scanner of claim 13, wherein the visor hinge comprises a pair of joints between the visor and the main scanner body.

15. The scanner of claim 14, wherein a joint comprises at least one of:

a hole in a side of the main scanner body and a corresponding plug on a side panel of the visor; and

a plug on the side of the main scanner body and a corresponding hole in the side panel of the visor.

16. The scanner of claim 13, wherein the visor hinge further comprises a locking element for temporarily locking the visor into one of a plurality of fixed angles of connection in relation to the main scanner body.

17. The scanner of claim 16, wherein the locking element is configured to temporarily lock the visor in an angle of approximately one hundred and eighty degrees in relation to the main scanner body;

wherein a first surface of the visor is substantially parallel to a surface of the main scanner body; and

wherein the visor is extended outward from the main scanner body to receive the forehead of the person and to determine a distance between the main scanner body and the head of the person.

18. The scanner of claim 16, wherein the locking element is configured to temporarily lock the visor in an angle of approximately zero degrees in relation to the main scanner body, wherein a first surface of the visor is substantially flush with a surface of the main scanner body.

19. The scanner of claim 16, wherein the plurality of fixed angles determine at least:

an open position of the visor in relation to the main scanner body, wherein the visor is configured to accept the head of the person for scanning; and

a closed position of the visor in relation to the main scanner body, wherein the scanner is in a most compact configuration.

20. The scanner of claim 16, wherein: the locking element comprises at least one of a notch on the

main scanner body or a locking plug on the main scanner body; and

10 Apr. 9, 2009

the locking element further comprises at least one of a locking plug on the visor corresponding to the notch on the main scanner body or a notch on the visor corresponding to the locking plug on the main scanner body;

wherein the fixed angle of connection between the visor and the main scanner body is created by at least one of the locking plug on the visor locking into the notch on the main scanner body or the notch on the visor locking into the locking plug on the main scanner body.

21. The scanner of claim 1 further comprising a cap attached to the visor, wherein the cap is configurable to protect an exterior area of the main scanner body.

22. The scanner of claim 21, further comprising a cap hinge coupling the cap to the visor.

23. The scanner of claim 22, wherein the cap hinge com-prises:

a first piano-hinge element on an edge of the visor; a second piano-hinge element on an edge of the cap; and a torsional spring; wherein the first piano-hinge element and the second

piano-hinge element interlock to form a rotating joint along the edge of the visor; and

wherein said rotating joint is a spring-actuated joint. 24. The scanner of claim 1, further comprising: a visor hinge which attaches the visor to the main scanner

body; a locking mechanism of the visor hinge configured to cre

ate a plurality of fixed angles of connection between the visor and the main scanner body, wherein the fixed angles determine at least one of an open position of the visor in relation to the main scanner body and a closed position of the visor in relation to the main scanner body; and

a cap attached to the visor, wherein the cap covers an exterior area of the scanner when the visor is in the closed position and the cap uncovers the exterior area of the scanner when the visor is in the open position.

25. The scanner of claim 24, further comprising a gasket for protecting the scanner when the visor is in the closed position.

26. The scanner of claim 25, wherein the gasket is at least one of a gasket of the cap or a gasket of the main scanner body, wherein the gasket of the main scanner body is substantially aligned with the cap.

27. The scanner of claim 24, further comprising a cap hinge coupling the cap to the visor.

28. The scanner of claim 27, wherein said cap hinge com-prises:

a first piano-hinge element on an edge of the visor; a second piano-hinge element on an edge of the cap; and a torsional spring; wherein the first piano-hinge element and the second

piano-hinge element interlock to form a rotating joint along the edge of the visor.

wherein the torsional spring is configured to press the cap closed over the exterior area when the visor is in the closed position; and

wherein the torsional spring is configured to press the cap flush against a surface of the scanner when the visor is in the open position.

29. The scanner of claim 1, wherein said visor further comprises a bottom element for shielding from an ambient lighting coming from below said scanner.


US 2009/0092292 AI

30. The scanner of claim 29, wherein said bottom element is configured to be removable.

31. The scanner of claim 1, wherein the visor is substantially opaque to light.

32. The scanner of claim 1, wherein the visor is configured to be substantially translucent to a first color oflight and to be substantially opaque to a second color of light.

33. The scanner of claim 1, wherein the scanner is configured to image at least a portion of a single eye of a person.

34. The scanner of claim 1, wherein the scanner is configured to image at least respective portions of a respective two eyes of a person.

35. The scanner of claim 1, wherein the visor is configured to substantially conform to a fall width of a forehead of the person.

36. The scanner of claim 1, wherein the visor is configured to substantially conform to a partial width of a forehead of the person.

37. The scanner of claim 1, wherein the visor is configured to adjust to a size of a forehead of the person.

38. A system for establishing a relative position between an optical system and the eye of a person comprising a visor with a first end coupled to the optical system and a second end for receiving a forehead of the person, the second end of the visor having a substantially fixed relative position in relation to the first end;

wherein the substantially fixed relative position of the second end in relation to the first end determines a relative position between the optical system and the eye of the

11 Apr. 9, 2009

person whose head is positioned at the visor, such that at least a portion of the eye is located in a field of view of the optical system allowing the optical system to obtain an image of at least a portion of the eye.

39. The system of claim 38, wherein the substantially fixed relative position of the second end in relation to the first end comprises a length of the visor between the second end and the first end;

wherein the length of the visor determines a distance between the optical system and the eye of the person whose head is positioned at the visor, such that at least a portion of the eye is located at a focal length of the optical system allowing the optical system to obtain an image of at least a portion of the eye.

40. The system of claim 38 further comprising an attaching element, wherein the visor is coupled to the optical system by being attached to the optical system.

41. The system of claim 40, wherein the attaching element comprises a visor hinge.

42. The system of claim 38, wherein the second end of the visor is contoured to substantially conform to a shape of a forehead of the person.

43. The system of claim 38, further comprising a cap attached to the visor, wherein the cap is configured to cover an exterior area of the optical system.

44. The system of claim 38, further comprising a locking element for temporarily locking the visor into a plurality of fixed angles of connection in relation to the optical system.

* * * * *


111111 1111111111111111111111111111111111111111111111111111111111111

c12) United States Patent Zhao

(54) SMALL CALIBER IMPLANTABLE BIOMETRIC LEADS AND CABLES FOR SAME

(75) Inventor: Yong D. Zhao, Simi Valley, CA (US)

(73) Assignee: Pacesetter, Inc., Sylmar, CA (US)

( *) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 534 days.

(21) Appl. No.: 12/370,461

(22) Filed: Feb.12,2009

(65) Prior Publication Data

US 2010/0204767 Al Aug. 12, 2010

(51) Int. Cl. A61N 1100 (2006.01)

(52) U.S. Cl. ....................................................... 607/122 (58) Field of Classification Search . ... ... ... ... .. ... . 607/122

(56)

See application file for complete search history.

References Cited

U.S. PATENT DOCUMENTS

4,712,555 A 4,788,980 A 4,940,052 A

12/1987 Thornander eta!. 12/1988 Mann eta!. 7/1990 Mann eta!.

~

US0081 08053B2

(10) Patent No.: US 8,108,053 B2 Jan.31,2012 (45) Date of Patent:

4,944,298 A 5,466,254 A 5,476,483 A 6,314,323 B1 7,366,556 B2 *

2007/0106144 A1 2009/0192577 A1 *

* cited by examiner

7/1990 Sholder 1111995 Helland 12/1995 Bornzin eta!. 1112001 Ekwall 4/2008 Brister eta!. ................. 600/347 5/2007 Squeri 7/2009 Desai ............................ 607/116

Primary Examiner- George Manuel

(57) ABSTRACT

Implantable medical leads have reduced diameter while providing for optimized mechanical and electrical properties, by reducing the diameters of the conducting cables used within the leads for sensing and delivery of therapeutic electrical stimulation. In an embodiment, conducting filaments within a cable have oval cross-sectional areas. Suitably orienting the oval filaments increases the contact surface between adjacent filaments, broadly distributing the pressure between filaments and reducing fretting fatigue, while the oval crosssectional area also increases conductivity. In an embodiment, non-conducting coatings around filaments within a cable, or around groups of filaments organized into cable-layers, reduce fretting fatigue. In an embodiment, the cross-sectional area of filaments decreases as the filaments are positioned at increasing radial distances from the center of the cable. In an embodiment, the relative composition of various filament metals and/or alloys is varied in filaments at different radial distances from the center of the cable.

21 Claims, 26 Drawing Sheets

108

«~~-

!til/ .:9 I I 144~ rrr \ 144"'

100

122

102


U.S. Patent Jan.31,2012

104

/ /

II! ( I I I \

121

Sheet 1 of26

144 144" 144""

108

FIG.

US 8,108,053 B2

1

122

102

100


1 00~ 1260 262 220"""] l I MEMORY I \ ·I PROGRAMMABLE

MICROCONTROLLER

FIG. 2

PROCESSOR

264 RAM,ROM

PROM

233 TIMING L...____ CONTROL 270 ;

PHYSIOLOGIC 234 ARRHYTHMIA SENSORS DETECTOR

IMPEDANCE

MORPHOLOGY DETECTOR

BATIERY CONTROL

M/AV/W MODULE

MEASURING ACTIVITY CIRCUIT

280

222 ATRIAL S ELEC

PULSE VLTIP GENERATOR

ALRING

ALCOIL

ARTIP

ARRING

ELECT. CASE CON FIG SWITCH VRRING

VENTR. 226 PULSE -GENERATOR VR TIP

~--:--!-----

~-I

RV COIL

svc COIL

~ 00 • ~ ~ ~ ~ = ~

""' ~ := (.H .... ~

N 0 .... N

rFJ

=('D ('D ..... N 0 -. N 0\

d rJl

"'Of:)

""""' = Of:) = u. w

= N


U.S. Patent Jan.31,2012 Sheet 3 of26 US 8,108,053 B2

COMMUNICATION INFRASTRUCTURE

306

I PROCESSOR I 304

" /254

30~

MAIN MEMORY

30~ 330 DISPLAY

~

I DISPLAY I INTERFACE

34~ 34~

DATA DATA ENTRY ENTRY

INTERFACE DEVICE

31.!!

SECOND MEMORY / 312

HARD DISK DRIVE

- REMOVABLE STORAGE DRIVE

INTERFACE

26~

COMMUNICATIONS - LINK (lCD INTERFACE)

32~

COMMUNICATIONS INTERFACE

FIG. J

/ 314

r----

/ 320

~ ---

328 \

,__\ __ f----

3 18

REMOVAB LE STORAGE UNIT

REMOVAB LE STORAGE UNIT

322 10.!!

lCD

r-

~...,_.



0 0

0 "'it

'\ 0 ~

~ "'it

• 10 ~ 0 G: "'it

(.!) Z(l) I-IW ~_J (.)(D

§f<S (/)


U.S. Patent

~ 0 q

Jan.31,2012

0

Sheet 6 of26 US 8,108,053 B2

0 I") o-q



0

~

'\ 0 lu 0 ~ .....

~

• ~ c::


U.S. Patent

1 (0 .--

I

.--q '6\.

0 II') II') q '6\.

~ '$

Jan.31,2012 Sheet 9 of26

IX) 0) -o-q

0 (0 ..--0 '$

It') ..--

..--q '$ '$

US 8,108,053 B2

0 IX)

"' 0 '$


U.S. Patent Jan.31,2012 Sheet 10 of 26 US 8,108,053 B2

505

515

l]t=~~~ 510.m

515

515

FIG. 5A


U.S. Patent

<( /

/ I() / 1.()-1.()

Jan.31,2012

<(

II) ...... I()

/ { ~ II) ...... I()

Sheet 11 of 26

I I") II) ...... 1.0

'\

' I ..._ '\ / -,

\ ...... ,, ,,

' ·-0 ...... I()

US 8,108,053 B2



526----..__

527

520

------------~

515

525

~ FATIGUE ZONE

~ FAST FRACTURE ZONE

FIG. 5E



0 0 "0 (Q Cl)

'\ E f'l)

tor) 0 0 (Q (Q

Sheet 13 of 26

0 LO

10 0 (Q

(0 E 10 -(Q

US 8,108,053 B2

~ • ~ c::


sneet 14 of 26 lJ.S. -patent

61 orn 620

615rfl

610.0

f/G. 68



0 •

lO "t--

eo


U.S. Patent

c c (0

'\

.,.... 0 0 q -H .,....

Jan.31,2012

.,.... 0 0 q -H .,.... .,.... 0

0 q

.,.... q

E lC') -(Q

Sheet 17 of 26

0 lC')

US 8,108,053 B2

LLJ (a

• (...)

G:



E ~,~~~ ~ ~~~~

Sheet 18 of 26 US 8,108,053 B2



700

715m 710.m )'

705

710.0

FIG. 78



...... 0 0 q

--H- (._) f' ...... 0 "' 0 ..... q

R 0 0

'\ ..... q ~ 0 2:1 G: 0 ...... q r-- 0

0 0

2:1 q q 0 2:1 ..... q ..... ..... '\9. 0 0

0 0 q q

2:1 ~ ...... 0 ~



810.m BOO

J

BJO

FIG. BA



co ...... 0 qLO 0-.;t-xq

0

Cl:J (0 O):::I: ...... (0

0 N au ~ q 0 01-

a q q_ a LO '& ca... ...... 'S. OJ 0 0 . "\

0 q ~ ...... 0

LL:

a ~ ......

OJ

...... LO 1.0 LOCO LO -.:1- ~ ...... I"') 0 0 gq q q 'S. 'S.

.a 0

:I: xu 1-

0)-ca.. 0 0 ci



910.m 900

/

9JO

FIG. 9A



co ...... 0

0 q

0 1.0 '$ 1'-0) 0 0

'\ 0 q ...... q

Sheet 24 of 26

0 It) -IX)

1.0 ~ 0

(0 mci t".. o:c 0 ou q ql-

o-sa..

US 8,108,053 B2

ca 0)

~ Cl::

1'-1.0 0 0



E tO 0

E 10 tO 0 tO - 10

~" 0 -

10 0 0)

tO' 0 ~ IX) 0

~r' tO' tO 0 10 E 0 0 - c:i "' - c:i 0) 10 g ~ 0 -(D -\

0

~ -E 0 tO tO - -IX) IX)

~r' ~r' 10 - - 0

"' E "' c:i e· c:i o"' IC)

tO 0 tO 10 - -- 0 (D (D -



1110

1120

FIG. 11


US 8,108,053 B2 1

SMALL CALIBER IMPLANTABLE BIOMETRIC LEADS AND CABLES FOR

SAME

FIELD OF THE INVENTION

The present invention relates generally to implantable cardiac therapy devices, and more specifically to implantable leads for implantable cardiac devices.

BACKGROUND

10

2 patible with the emerging screw-driver stylet and/or slitable/ steerable catheter, which benefits even more from a smaller size ICD lead.

Yet another aspect oflead design is enhanced lead removability, which becomes possible with leads that exhibit only minor fibrotic encapsulation. The degree of fibrosis engendered by a lead may be altered by optimized lead body materials and coatings, but here again a reduced electrical lead size contributes as well.

Yet another objective oflead design is MRI compatibility, which places specific requirements on the conductors for sizes, layout, insulation, etc.

The various operational requirements for ICTD leads, as specified above, create competing design requirements. In

Implantable cardiac therapy devices (ICTDs) enjoy widespread use for providing convenient, portable, sustained therapy for cardiac patients with a variety of cardiac arrhythmias. ICTDs may combine a pacemaker and defibrillator in a single implantable device. Such devices may be configured to provide ongoing cardiac pacing in order to maintain an appropriate cardiac rhythm. In addition, should the ICTD detect that the patient is experiencing an episode of ventricular fibrillation (or an episode of ventricular tachycardia), the ICTD can deliver appropriate defibrillation therapy.

15 general, thinner leads contribute to flexibility and allow for maximum circulation within blood vessels. At the same time, it is known that fretting fatigue is the primary failure mode of a small-sized lead made of multiple filament wires; for example, the center filament wire is usually broken first in an

20 existing 1 x19 cable where all of the wires are of the same size.

Cardiac rhythm management (CRM) therapies require not only an ICTD, but also the placement of electrical leads 25

threaded through blood vessels and typically into the heart itself. Patients with implanted electrical leads benefit from leads which exhibit optimized properties in terms of size (that

Further, smaller leads exhibit lower tensile strength. Also, when the lead size becomes smaller, the DC resistance of the cable increases, which in turn decreases the capability to carry large currents.

It will be noted that while implantable leads are essential in the field of cardiac rhythm management (CRM) therapies, they are employed in many other biomedical applications as well. For example, implantable leads have applications in neurology for treatment of Parkinson's disease, epilepsy, is, minimal lead width or diameter), flexibility, strength, and

reliability (including resistance to breaking), and various electrical properties such as low impedance (in order to carry large current loads).

With advances in both CRM therapy and ICTD technologies, the device implant pathway can become busy with three

30 chronic back pain, and other conditions. Many of the requirements identified above, such as small size (i.e., being as thin as possible), flexibility, durability, and low resistance are requirements for these other applications as well.

What is needed, then, is an apparatus for an implantable 35 lead for use with an ICTD, and for other implantable medical

applications as well, with a smaller size lead which none-theless exhibits optimized performance for implantation in relation to existing leads including, for example:

or more cables (for example, cables may be required for treating bradycardia, tachycardia, defibrillation, cardiac pacing, for standalone sensors, etc.). These multiple leads may need to be placed inside only one or two veins, which in turn benefit from smaller size leads to ensure adequate circulation 40 through the blood vessels. Adding new sensor based diagnos-tic features, such as LAP (left atrial pressure), RVP (right ventricular pressure), and Sv02 (blood oxygen sensor), requires creating additional space in the implant pathway or the lead body for the diagnostic circuits. Therefore, the addi- 45

tion of such sensors requires that the regular ICD lead diameter again must be reduced. Potential target drug delivery and target biological therapy delivery of tissues, cells, antibodies genes, etc. needs to be specifically delivered via a lead channel in the given vein with the new ICD leads. All of these 50

therapeutic demands create requirements for the thinnest possible leads consistent with other lead requirements (flexibility, durability, low electrical resistance, and others).

With recent advances in cardiac therapies, alternative ICD lead implant sites are increasingly used. These include: the 55

right ventricular outflow tract (ROT), the right ventricular (RV) high septum, and other sites in the right heart; and also the cardiac septum (CS), the great cardiac vein, and other areas of the left heart. To this end, the ICD leads must be robust and flexible for site specific positioning, and for ease of 60

implantation through the torturous and complex implant pathways. ICTD leads also require improved acute and chronic stability at the desired site to reliably deliver the desired therapies for the entire design life of the system.

As is well known in the art, there are also different delivery 65

methods to implant leads in the heart. The ICD lead should be compatible with traditional stylet delivery, and also be com-

flexible bending but higher tension strength; higher fatigue life; stronger ability to resist kinking; better electrical conductivity; lower DC resistance to carry large current during cardiac

shocking.

BRIEF SUMMARY

The cable and lead designs presented herein show optimal mechanical and electrical performances especially for applications such as ICTD leads. The present cable and lead designs are directed towards reducing the diameter of leads, while providing for optimized mechanical and electrical properties, by reducing the diameters of the conducting cables used within the leads for both sensing and delivery of therapeutic electrical stimulation.

The diameter of the conducting cables may be reduced via multiple strategies. In an embodiment of the present cable and lead designs, conducting filaments within the lead are configured to have oval cross-sectional areas. By suitably orienting the oval filaments within a cable, it is possible to increase the contact surface between adjacent filaments. The increased contact surface area broadly distributes the pressure between filaments, resulting in reduced fretting fatigue. At the same time, the oval cross-sectional area increases conductivity and reduces DC resistance.

In an embodiment of the present cable and lead designs, suitable non-conductive coatings or jackets are employed


US 8,108,053 B2 3

around filaments within a cable, or around groups of filaments organized into cable-layers. The coatings or jackets reduce fretting fatigue, which enhances cable life and allows for the use of thinner filaments.

4 FIGS. 6A-6E, 7 A-7C, SA, SB, 9A, and 9B, as appropriate, as well as to the disclosure associated with those figures

FIG. 1 is a simplified diagram illustrating an exemplary implantable cardiac therapy device (ICTD) in electrical communication with a patient's heart by means ofleads suitable for delivering multi-chamber stimulation and pacing therapy, and for detecting cardiac electrical activity.

In an embodiment of the present cable and lead designs, the cross-sectional area of filaments used in a cable decreases as the filaments are positioned at increasing radial distance from the center of the cable. This configuration contributes to both structural strength and flexibility of the cable, while enabling a reduced cable diameter and maintaining optimized electrical properties.

In an embodiment of the present cable and lead designs, the relative composition of various metals and/or alloys of filaments in the cable is varied in relation to different radial distances of the filaments from the center of the cable. This configuration contributes both to structural strength and flexibility of the cables, while reducing cable diameter and maintaining optimized electrical properties.

FIG. 2 is a functional block diagram of an exemplary ICTD that can detect cardiac electrical activity and analyze cardiac

10 electrical activity, as well as provide cardioversion, defibrillation, and pacing stimulation in four chambers of a heart.

FIG. 3 is a system diagram representing an exemplary computer, computational system, or other programming

15 device which may be used to program an ICTD.

FIG. 4A illustrates a cross-sectional view of an exemplary implantable ICTD lead according to an embodiment of the present cable and lead designs.

Other and further features, advantages, and benefits of the present cable and lead designs will become apparent in the following description taken in conjunction with the following drawings. It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory but are not to be restrictive of the invention. The accompanying drawings which are incorporated in and constitute a part of this invention, illustrate only several of many possible embodiments of the invention, and together with the description, serve to explain the principles of the invention in general terms.

FIG. 4B illustrates another cross-sectional v1ew of the 20 exemplary lead shown in FIG. 4A.

FIG. 4C illustrates another cross-sectional view of the exemplary lead shown in FIG. 4A with a different set of dimensions than those shown in FIG. 4B.

FIG. 4D illustrates another cross-sectional view of the 25 exemplary lead shown in FIG. 4A with a different set of

dimensions than those shown in FIG. 4B or FIG. 4C. FIG. 4E illustrates a cross-sectional view of another exem

plary implantable ICTD lead according to the present cable and lead designs.


3° FIG. 4F illustrates another view of the exemplary lead shown in FIG. 4E.

The accompanying drawings, which are incorporated herein and form part of the specification, illustrate the meth- 35

ods and systems presented herein for conductor cable designs for small caliber leads for an ICTD. Together with the detailed description, the drawings further serve to explain the principles of, and to enable a person skilled in the relevant art(s) to make and use the methods and systems presented herein. 40

In the drawings, like reference numbers indicate identical or functionally similar elements. Further, the drawing in which an element first appears is typically indicated by the leftmost digit( s) in the corresponding reference number (e.g., an element numbered 302 first appears in FIG. 3). 45

FIG. SA illustrates an exemplary cable which may be part of a lead.

FIG. SB illustrates a cross-sectional view of the cable shown in FIG. SA.

FIG. SC illustrates a contact mode between two adjacent filaments which are part of a single cable-layer of a cable.

FIG. SD illustrates a contact mode between two filaments, each filament being part of a respective one of two adjacent cable-layers of a cable.

FIG. SE illustrates a fretting fatigue fracture morphology of a fine wire filament of a cable subjected to cyclic flex loading.

FIG. 6A illustrates an exemplary cable configured for improved mechanical and electrical properties according the present cable and lead designs.

FIG. 6B illustrates another view of the exemplary cable shown in FIG. 6A.

FIG. 6C illustrates an exemplary cable-layer of the cable shown in FIG. 6A.

FIG. 6D illustrates another exemplary cable-layer of the cable shown in FIG. 6A.

Additionally, some elements may be labeled with only a number to indicate a generic form of the element, while other elements labeled with the same number followed by another number or a letter (or a letter/number combination) may indicate a species of the element. For example, a generic 50

filament of a cable may be labeled as S1S. A filament associated specifically with an inner cable-layer may be labeled as S1S.i, a filament associated with a middle cable-layer as S1S.m, and a filament associated with an outer cable-layer as S1S.o.

FIG. 6E illustrates another view of the exemplary cable of 55 FIG. 6A.

FIG. 7 A illustrates another exemplary cable configured for improved mechanical and electrical properties according the present cable and lead designs.

When referring to the figures, reference is sometimes made to a specific figure, for example, FIG. SA, FIG. SB, FIG. 6A, FIG. 10, etc. In other instances, especially where a group of figures illustrate different views and/or different sub-elements of a common element, reference may be made for convenience to the group of figures by way of a common figure number. For example, a reference to "FIG. 6" will be understood in this document as referring to all of, or to contextually pertinent aspects of, FIGS. 6A, 6B, 6C, 6D, and/or

FIG. 7B illustrates another view of the exemplary cable of 60 FIG. 7A.

6E as appropriate, as well as to the disclosure associated with 65

those figures. A reference to "FIGS. 6-9" will be understood as referring to all of, or to contextually pertinent aspects of,

FIG. 7C illustrates another view of the exemplary cable of FIG. 7A.

FIG. SA illustrates another exemplary cable configured for improved mechanical and electrical properties according the present cable and lead designs.

FIG. SB illustrates another view of the exemplary cable of FIG. SA.


US 8,108,053 B2 5

FIG. 9A illustrates another exemplary cable configured for improved mechanical and electrical properties according the present cable and lead designs.

FIG. 9B illustrates another view of the exemplary cable of FIG. 9A.

FIG. 10 illustrates cross-sectional views of several exemplary filaments which may be part of a cable configured for improved mechanical and electrical properties according the present cable and lead designs.

FIG. 11 illustrates an exemplary rope cable.

DETAILED DESCRIPTION

Overview The following detailed description of systems and methods

for conductor cable designs of small caliber ICTD leads for an implantable cardiac therapy device refers to the accompanying drawings that illustrate exemplary embodiments consistent with these systems and methods. Other embodiments are possible, and modifications may be made to the embodiments within the spirit and scope of the methods and systems presented herein. Therefore, the following detailed description is not meant to limit the methods and systems described herein. Rather, the scope of these methods and systems is defined by the appended claims.

It would be apparent to one of skill in the art that the systems and methods for conductor cable designs of small caliber ICTD leads for an implantable cardiac therapy device, as described below, may be implemented in many different embodiments of hardware, materials, construction methods, and/or the entities illustrated in the figures. Any actual hardware, materials, and/or construction methods described or illustrated herein is not limiting of these methods and systems. In addition, more than one embodiment of the present cable and lead designs may be presented below, and it will be understood that not all embodiments necessarily exhibit all elements, that some elements may be combined or connected in a manner different than that specifically described herein, and that some differing elements from the different embodiments presented herein may be functionally and structurally combined to achieve still further embodiments of the present cable and lead designs.

Thus, the operation and behavior of the methods and systems will be described with the understanding that modifications and variations of the embodiments are possible, given the level of detail presented herein.

It will be noted that while the exemplary embodiments presented below describe implantable leads, and cable conductors for use in the leads, used in the context of CRM therapies, the applications of the present cable and lead designs are not confined solely to leads employed for CRM therapies or to leads used in conjunction with ICTDs. For example, the exemplary leads described herein, and other similar leads falling within the scope of the appended claims, may be employed in other biomedical applications as well. For example, the implantable leads may have applications in neurology for treatment of Parkinson's disease, epilepsy, chronic back pain, etc. The leads may have other biomedical applications as well, and due to their various advantages, such as small size (i.e., being as thin as possible), flexibility, durability, and low resistance, and may even find beneficial applications in non-medical or non-biological applications as well. Exemplary Environment--Overview

Before describing in detail the methods and systems for conductor cable designs of small caliber ICTD leads for an implantable cardiac therapy device, it is helpful to describe an example environment in which these methods and systems

6 may be implemented. The methods and systems described herein may be particularly useful in the environment of an implantable cardiac therapy device (ICTD).

An ICTD may also be referred to synonymously herein as a "stimulation device", emphasizing the role of the ICTD in providing pacing and shocking to a human heart. However, an ICTD may provide operations or services in addition to stimulation, including but not limited to cardiac monitoring.

An ICTD is a physiologic measuring device and therapeu-10 tic device that is implanted in a patient to monitor cardiac

function and to deliver appropriate electrical therapy, for example, pacing pulses, cardioverting and defibrillator pulses, and drug therapy, as required. ICTDs include, for example and without limitation, pacemakers, cardioverters,

15 defibrillators, implantable cardioverter defibrillators, implantable cardiac rhythm management devices, and the like. Such devices may also be used in particular to monitor cardiac electrical activity and to analyze cardiac electrical activity. The term "implantable cardiac therapy device" or

20 simply "ICTD" is used herein to refer to any such implantable cardiac device.

FIGS. 1 and 2 illustrate such an environment. Exemplary ICTD in Electrical Communication with a Patient's Heart

25 The techniques described below are intended to be imple-mented in connection with any ICTD or any similar stimulation device that is configured or configurable to stimulate nerves and/or stimulate and/or shock a patient's heart.

FIG. 1 shows an exemplary stimulation device 100 in elec-30 trical communication with a patient's heart 102 by way of

three leads 104, 106, 108, suitable for delivering multi-chamber stimulation and shock therapy. The leads 104, 106, 108 are optionally configurable for delivery of stimulation pulses suitable for stimulation of autonomic nerves. In addition, the

35 device 100 includes a fourth lead 110 having, in this implementation, three electrodes 144, 144', 144" suitable for stimulation of autonomic nerves. This lead may be positioned in and/or near a patient's heart or near an autonomic nerve within a patient's body and remote from the heart. Of course,

40 such a lead may be positioned epicardially or at some other location to stimulate other tissue.

As described further below in this document, exemplary leads 104, 106, 108, 110 have at least one interior electrically conducting cable, and may have multiple interior electrically

45 conducting cables. The present cable and lead designs provide improved cable designs for use in leads such as exemplary leads 104, 106, 108, 110. Such improvements pertain to both mechanical and electrical properties of the cables, with resulting improvements in the mechanical and electrical

50 properties ofleads 104, 106, 108, 110. General background information on cable designs is pro

vided in FIGS. SA-SD along with the associated description, with discussion of some of the advantages of the present cable and lead designs being presented in conjunction with FIG. SF.

55 The present lead and cable designs are described in further detail later in this document, particularly but not exclusively in the section of this document titled "Cable Designs Overview;" and also with reference to exemplary leads 400 and 420 illustrated in FIGS. 4A-4F; exemplary cable conductors

60 600, 700, 800, and 900 illustrated in FIGS. 6-9; and exemplary central wires 605, 705, 805, 905 and exemplary filaments 615, 715, 815, 915 illustrated in various illustrations of FIGS. 6-10. It will be understood by persons skilled in the relevant arts that leads 104, 106, 108, 110 and other leads used

65 in conjunction with operations of ICTD 100 may employ designs the same as or similar to exemplary leads 400, 420; and may further employ conducting cables, central wires, and


US 8,108,053 B2 7

filaments the same as, or embodying elements of, exemplary cable conductors 600, 700, 800, and 900, exemplary central wires 605, 705, 805, 905, and exemplary filaments 615, 715, 815, 915, as described further below in this document.

The right atrial lead 104, as the name implies, is positioned in and/or passes through a patient's right atrium. The right atrial lead 104 optionally senses atrial cardiac signals and/or provide right atrial chamber stimulation therapy. As shown in FIG. 1, the stimulation device 100 is coupled to an implantable right atrial lead 104 having, for example, an atrial tip electrode 120, which typically is implanted in the patient's right atrial appendage. The lead 104, as shown in FIG. 1, also includes an atrial ring electrode 121. Of course, the lead 104 may have other electrodes as well. For example, the right atrial lead optionally includes a distal bifurcation having electrodes suitable for stimulation of autonomic nerves.

To sense atrial cardiac signals, ventricular cardiac signals and/or to provide chamber pacing therapy, particularly on the left side of a patient's heart, the stimulation device 100 is coupled to a coronary sinus lead 106 designed for placement in the coronary sinus and/or tributary veins of the coronary sinus. Thus, the coronary sinus lead 106 is optionally suitable for positioning at least one distal electrode adjacent to the left ventricle and/or additional electrode(s) adjacent to the left atrium. In a normal heart, tributary veins of the coronary sinus include, but may not be limited to, the great cardiac vein, the left marginal vein, the left posterior ventricular vein, the middle cardiac vein, and the small cardiac vein.

Accordingly, an exemplary coronary sinus lead 106 is optionally designed to receive atrial and ventricular cardiac signals and to deliver left ventricular pacing therapy using, for example, at least a left ventricular tip electrode 122, left atrial pacing therapy using at least a left atrial ring electrode 124, and shocking therapy using at least a left atrial coil electrode 126. For a complete description of a coronary sinus lead, the reader is directed to U.S. Pat. No. 5,466,254, "Coronary Sinus Lead with Atrial Sensing Capability" (Helland), which is incorporated herein by reference. The coronary sinus lead 106 further optionally includes electrodes for stimulation of autonomic nerves. Such a lead may include pacing and autonomic nerve stimulation functionality and may further include bifurcations or legs. For example, an exemplary coronary sinus lead includes pacing electrodes capable of delivering pacing pulses to a patient's left ventricle and at least one electrode capable of stimulating an autonomic nerve. An exemplary coronary sinus lead (or left ventricular lead or left atrial lead) may also include at least one electrode capable of stimulating an autonomic nerve, such an electrode may be positioned on the lead or a bifurcation or leg of the lead.

8 Functional Elements of an Exemplary ICTD

An implantable cardiac therapy device may be referred to variously, and equivalently, throughout this document as an "implantable cardiac therapy device", an "ICTD", an "implantable device", a "stimulation device", and the respective plurals thereof.

FIG. 2 shows an exemplary, simplified block diagram depicting various components of stimulation device 100. The stimulation device 100 can be capable of treating both fast

10 and slow arrhythmias with stimulation therapy, including cardioversion, defibrillation, and pacing stimulation. The stimulation device can be solely or further capable of delivering stimuli to autonomic nerves. While a particular multichamber device is shown, it is to be appreciated and under-

15 stood that this is done for illustration purposes only. For example, various methods may be implemented on a pacing device suited for single ventricular stimulation and not hiventricular stimulation. Thus, the techniques and methods described below can be implemented in connection with any

20 suitably configured or configurable stimulation device. Accordingly, one of skill in the art could readily duplicate, eliminate, or disable the appropriate circuitry in any desired combination to provide a device capable of treating the appropriate chamber(s) or regions of a patient's heart with cardio-

25 version, defibrillation, pacing stimulation, and/or autonomic nerve stimulation.

Housing 200 for stimulation device 100 is often referred to as the "can", "case" or "case electrode", and may be programmably selected to act as the return electrode for all "unipolar"

30 modes. Housing 200 may further be used as a return electrode alone or in combination with one or more of the coil electrodes 126,132 and 134 (see FIG. 1) for shocking purposes. Housing 200 further includes a connector (not shown) having a plurality of terminals 201, 202, 204, 206, 208, 212, 214,

35 216, 218, 221 (shown schematically and, for convenience, the names of the electrodes to which they are connected are shown next to the terminals).

To achieve right atrial sensing, pacing and/or autonomic stimulation, the connector includes at least a right atrial tip

40 terminal (AR TIP) 202 adapted for connection to the atrial tip electrode 120. A right atrial ring terminal (AR RING) 201 is also shown, which is adapted for connection to the atrial ring electrode 121. To achieve left chamber sensing, pacing, shocking, and/or autonomic stimulation, the connector

45 includes at least a left ventricular tip terminal (VL TIP) 204, a left atrial ring terminal (AL RING) 206, and a left atrial shocking terminal (AL COIL) 208, which are adapted for connection to the left ventricular tip electrode 122, the left atrial ring electrode 124, and the left atrial coil electrode 126,

50 respectively. Connection to suitable autonomic nerve stimulation electrodes is also possible via these and/or other terminals (e.g., via a nerve stimulation terminalS ELEC 221).

Stimulation device 100 is also shown in electrical communication with the patient's heart 102 by way of an implantable right ventricular lead 108 having, in this exemplary implementation, a right ventricular tip electrode 128, a right ventricular ring electrode 130, a right ventricular (RV) coil electrode 132, and an superior vena cava (SVC) coil electrode 134. Typically, the right ventricular lead 108 is transvenously inserted into the heart 102 to place the right ventricular tip electrode 128 in the right ventricular apex so that the RV coil electrode 132 will be positioned in the right ventricle and the SVC coil electrode 134 will be positioned in the superior vena cava. Accordingly, the right ventricular lead 108 is capable of sensing or receiving cardiac signals, and delivering stimulation in the form of pacing and shock therapy to the right ventricle. An exemplary right ventricular lead may also include at least one electrode capable of stimulating an auto- 65

nomic nerve, such an electrode may be positioned on the lead

To support right chamber sensing, pacing, shocking, and/or autonomic nerve stimulation, the connector further includes a

55 right ventricular tip terminal (VR TIP) 212, a right ventricular ring terminal (VR RING) 214, a right ventricular shocking terminal (RV COIL) 216, and a superior vena cava shocking terminal (SVC COIL) 218, which are adapted for connection to the right ventricular tip electrode 128, right ventricular ring

60 electrode 130, the RV coil electrode 132, and the SVC coil electrode 134, respectively. Connection to suitable autonomic nerve stimulation electrodes is also possible via these and/or other terminals (e.g., via the nerve stimulation termi-nal S ELEC 221).

At the core of the stimulation device 100 is a programmable microcontroller 220 that controls the various modes of stimulation therapy. As is well known in the art, microcon-or a bifurcation or leg of the lead.


US 8,108,053 B2 9

troller 220 typically includes a processor or microprocessor 231, or equivalent control circuitry, designed specifically for controlling the delivery of stimulation therapy, and may further include onboard memory 232 (which may be, for example and without limitation, RAM, ROM, PROM, one or more internal registers, etc.), logic and timing circuitry, state machine circuitry, and I/0 circuitry.

Typically, microcontroller 220 includes the ability to process or monitor input signals (data or information) as controlled by a program code stored in a designated block of 10

memory. The type of microcontroller is not critical to the described implementations. Rather, any suitable microcontroller 220 may be used that carries out the functions described herein. The use of microprocessor-based control circuits for performing timing and data analysis functions are 15

well known in the art. Representative types of control circuitry that may be used

in connection with the described embodiments can include the microprocessor-based control system of U.S. Pat. No. 4,940,052 (Marm et a!.), the state-machine of U.S. Pat. No. 20

4,712,555 (Thornander) and U.S. Pat. No. 4,944,298 (Sholder), all of which are incorporated by reference herein. For a more detailed description of the various timing intervals used within the stimulation device and their inter-relationship, see U.S. Pat. No. 4,788,980 (Mann eta!.), also incorpo- 25

rated herein by reference. FIG. 2 also shows an atrial pulse generator 222 and a

ventricular pulse generator 224 that generate pacing stimulation pulses for delivery by the right atrial lead 104, the coronary sinus lead 106, and/or the right ventricular lead 108 via 30

an electrode configuration switch 226. It is understood that in order to provide stimulation therapy in each of the four chambers of the heart (or to autonomic nerves or other tissue) the atrial and ventricular pulse generators, 222 and 224, may include dedicated, independent pulse generators, multiplexed 35

pulse generators, or shared pulse generators. The pulse generators 222 and 224 are controlled by the microcontroller 220 via appropriate control signals 228 and 230, respectively, to trigger or inhibit the stimulation pulses.

Microcontroller 220 further includes timing control cir- 40

cui try 233 to control the timing of the stimulation pulses (e.g., pacing rate, atrio-ventricular (e.g., AV) delay, atrial interconduction (AA) delay, or ventricular interconduction (VV) delay, etc.) as well as to keep track of the timing of refractory periods, blanking intervals, noise detection windows, evoked 45

response windows, alert intervals, marker channel timing, etc., which is well known in the art.

Microcontroller 220 further includes an arrhythmia detec-tor 234, a morphology detector 236, and optionally an orthostatic compensator and a minute ventilation (MY) response 50

module (the latter two are not shown in FIG. 2). These components can be utilized by the stimulation device 100 for determining desirable times to administer various therapies, including those to reduce the effects of orthostatic hypotension. The aforementioned components may be implemented 55

in hardware as part of the microcontroller 220, or as software/ firmware instructions programmed into the device and executed on the microcontroller 220 during certain modes of operation.

Microcontroller 220 further includes an AA delay, AV 60

delay and/or VV delay module 238 for performing a variety of tasks related to AA delay, AV delay and/or VV delay. This component can be utilized by the stimulation device 100 for determining desirable times to administer various therapies, including, but not limited to, ventricular stimulation therapy, 65

hi-ventricular stimulation therapy, resynchronization therapy, atrial stimulation therapy, etc. TheAA/AV/VV mod-

10 ule 238 may be implemented in hardware as part of the microcontroller 220, or as software/firmware instructions programmed into the device and executed on the microcontroller 220 during certain modes of operation. Of course, such a module may be limited to one or more of the particular functions of AA delay, AV delay and/or VV delay. Such a module may include other capabilities related to other functions that may be germane to the delays. Such a module may help make determinations as to fusion.

The microcontroller 220 ofFIG. 2 also includes an activity module 239. This module may include control logic for one or more activity related features. For example, the module 239 may include an algorithm for determining patient activity level, calling for an activity test, calling for a change in one or more pacing parameters, etc. These algorithms are described in more detail with respect to the figures. The module 239 may be implemented in hardware as part of the microcontroller 220, or as software/firmware instructions programmed into the device and executed on the microcontroller 220 during certain modes of operation. The module 239 may act cooperatively with theAA/AV/VV module 238.

Microcontroller 220 may also include a battery control module 286. Battery control module 286 may be used, for example, to control a battery 276. Battery control286 may be hardwired circuitry, or may be implemented as software or firmware running on microcontroller 220. Battery control 286 may be coupled to battery 276 via battery signal line 290 and battery control line 292. Battery signal line 290 may deliver to battery control 286 status or operational information regarding battery 276. Battery control line 292 may be used to change an operational state of battery 276. For example, battery control line 292 may deliver control signals from battery control 286 to battery 276.

In an alternative embodiment, battery control286 may be a separate module from microcontroller 220, but may be coupled to microcontroller 220. For example, separate module battery control286 may obtain required ICTD operational status information from microcontroller 220. Or, for example, separate module battery control 286 may report battery status or battery operational information to microcontroller 220. In addition, separate module battery control 286 may also be coupled to battery 276.

In an alternative embodiment, battery control 286 may be implemented as an internal physical module of battery 276 (for example, battery control 286 may be implemented as a microchip which is situated internally to the exterior housing of battery 276). However, battery control 286 may still be coupled to microcontroller 220 via battery signal line 290 and battery control line 292. In an alternative embodiment, battery control functions of battery control 286 may be distributed across a first module which is part ofbattery 276, and one or more additional modules which are external to battery 276. The battery control module(s) external to battery 276 may for example be part of microcontroller 220.

The electrode configuration switch 226 includes a plurality of switches for connecting the desired electrodes to the appropriate I/0 circuits, thereby providing complete electrode programmability. Accordingly, switch 226, in response to a control signal 242 from the microcontroller 220, determines the polarity of the stimulation pulses (e.g., unipolar, bipolar, combipolar, etc.) by selectively closing the appropriate combination of switches (not shown) as is known in the art.

Atrial sensing circuits 244 and ventricular sensing circuits 246 may also be selectively coupled to the right atrial lead 104, coronary sinus lead 106, and the right ventricular lead 108, through the switch 226 for detecting the presence of cardiac activity in each of the four chambers of the heart.


US 8,108,053 B2 11

Accordingly, the atrial (ATR. SENSE) and ventricular (VTR. SENSE) sensing circuits, 244 and 246, may include dedicated sense amplifiers, multiplexed amplifiers, or shared amplifiers. Switch 226 determines the "sensing polarity" of the cardiac signal by selectively closing the appropriate switches, as is also known in the art. In this way, the clinician may program the sensing polarity independent of the stimulation polarity. The sensing circuits (e.g., 244 and 246) are optionally capable of obtaining information indicative of tissue capture.

Each sensing circuit 244 and 246 preferably employs one 10

or more low power, precision amplifiers with programmable gain and/or automatic gain control, bandpass filtering, and a threshold detection circuit, as known in the art, to selectively sense the cardiac signal of interest. The automatic gain control enables the device 100 to deal effectively with the difficult 15

problem of sensing the low amplitude signal characteristics of atrial or ventricular fibrillation.

12 106, the right ventricular lead 108 and/or the nerve stimulation lead 110 through the switch 226 to sample cardiac signals across any pair of desired electrodes.

The microcontroller 220 is further coupled to a memory 260 by a suitable data/address bus 262, wherein the programmable operating parameters used by the microcontroller 220 are stored and modified, as required, in order to customize the operation of the stimulation device 100 to suit the needs of a particular patient. Such operating parameters define, for example, pacing pulse amplitude, pulse duration, electrode polarity, rate, sensitivity, automatic features, arrhythmia detection criteria, and the amplitude, waveshape, number of pulses, and vector of each shocking pulse to be delivered to the patient's heart 102 within each respective tier of therapy. One feature may be the ability to sense and store a relatively large amount of data (e.g., from the data acquisition system 252), which data may then be used for subsequent analysis to guide the progrming of the device.

Essentially, the operation of the ICTD control circuitry, The outputs of the atrial and ventricular sensing circuits

244 and 246 are connected to the microcontroller 220, which, in tum, is able to trigger or inhibit the atrial and ventricular pulse generators 222 and 224, respectively, in a demand fashion in response to the absence or presence of cardiac activity in the appropriate chambers of the heart. Furthermore, as described herein, the microcontroller 220 is also capable of analyzing information output from the sensing circuits 244 and 246 and/or the analog-to-digital (A/D) data acquisition system 252 to determine or detect whether and to what degree tissue capture has occurred and to program a pulse, or pulses,

20 including but not limited to pulse generators, timing control circuitry, delay modules, the activity module, battery utilization and related voltage and current control, and sensing and detection circuits, may be controlled, partly controlled, or fine-tuned by a variety of parameters, such as those indicated

25 above which may be stored and modified, and may be set via an external ICTD progrming device.

in response to such determinations. The sensing circuits 244 and 246, in turn, receive control signals over signal lines 248 and 250 from the microcontroller 220 for purposes of controlling the gain, threshold, polarization charge removal circuitry (not shown), and the timing of any blocking circuitry (not shown) coupled to the inputs of the sensing circuits, 244 and 246, as is known in the art.

Advantageously, the operating parameters of the implantable device 100 may be non-invasively progrmed into the memory 260 through a telemetry circuit 264 in telemetric

30 communication via communication link 266 with the external device 254, such as a general purpose computer, a dedicated ICTD programmer, a transtelephonic transceiver, or a diagnostic system analyzer. The microcontroller 220 activates the telemetry circuit 264 with a control signal268. The telemetry

35 circuit 264 advantageously allows intracardiac electrograms and status information relating to the operation of the device 100 (as contained in the microcontroller 220 or memory 260) to be sent to the external device 254 through an established

For arrhythmia detection, the device 100 utilizes the atrial and ventricular sensing circuits, 244 and 246, to sense cardiac signals to determine whether a rhythm is physiologic or pathologic. In reference to arrhythmias, as used herein, "sensing" is reserved for the noting of an electrical signal or obtain- 40

ing data (information), and "detection" is the processing (analysis) of these sensed signals and noting the presence of an arrhythmia. In some instances, detection or detecting includes sensing and in some instances sensing of a particular signal alone is sufficient for detection (e.g., presence/ab- 45

sence, etc.). The timing intervals between sensed events (e.g., P-waves,

R-waves, and depolarization signals associated with fibrillation which are sometimes referred to as "F-waves" or "Fibwaves") are then classified by the arrhythmia detector 234 of 50

the microcontroller 220 by comparing them to a predefined rate zone limit (i.e., bradycardia, normal, low rate VT, high rate VT, and fibrillation rate zones) and various other characteristics (e.g., sudden onset, stability, physiologic sensors, and morphology, etc.) in order to determine the type of reme- 55

dial therapy that is needed (e.g., bradycardia pacing, antitachycardia pacing, cardioversion shocks or defibrillation shocks, collectively referred to as "tiered therapy").

communication link 266. The ICTD 100 may also receive human programmer instructions via the external device 254.

The stimulation device 100 can further include a physiologic sensor 270, commonly referred to as a "rate-responsive" sensor because it is typically used to adjust pacing stimulation rate according to the exercise state of the patient. However, the physiological sensor 270 may further be used to detect changes in cardiac output (see, e.g., U.S. Pat. No. 6,314,323, entitled "Heart stimulator determining cardiac output, by measuring the systolic pressure, for controlling the stimulation", to Ekwall, issued Nov. 6, 2001, which discusses a pressure sensor adapted to sense pressure in a right ventricle and to generate an electrical pressure signal corresponding to the sensed pressure, an integrator supplied with the pressure signal which integrates the pressure signal between a start time and a stop time to produce an integration result that corresponds to cardiac output), changes in the physiological condition of the heart, or diurnal changes in activity (e.g., detecting sleep and wake states). Accordingly, the microcontroller 220 may respond by adjusting the various pacing parameters (such as rate, AA delay, AV delay, W delay, etc.) at which the atrial and ventricular pulse generators, 222 and 224, generate stimulation pulses.

Cardiac signals are also applied to inputs of an analog-todigital (A/D) data acquisition system 252. The data acquisi- 60

tion system 252 is configured to acquire intracardiac electrogram (EGM) signals, convert the raw analog data into a digital signal, and store the digital signals for later processing and/or telemetric transmission to an external device 254. Data acquisition system 252 may be configured by microcontroller 220 via control signals 256. The data acquisition system 252

While shown as being included within the stimulation device 100, it is to be understood that the physiologic sensor 270 may also be external to the stimulation device 100, yet

65 still be implanted within or carried by the patient. Examples of physiologic sensors that may be implemented in device 100 include known sensors that, for example, sense respira-is coupled to the right atrial lead 104, the coronary sinus lead


US 8,108,053 B2 13

tion rate, pH of blood, ventricular gradient, cardiac output, preload, afterload, contractility, hemodynamics, pressure, and so forth. Another sensor that may be used is one that detects activity variance, wherein an activity sensor is monitored diurnally to detect the low variance in the measurement corresponding to the sleep state. For a complete description of an example activity variance sensor, the reader is directed to U.S. Pat. No. 5,476,483 (Bornzinetal.), issuedDec.19, 1995, which patent is hereby incorporated by reference.

More specifically, the physiological sensors 270 optionally include sensors for detecting movement and minute ventilation in the patient. The physiological sensors 270 may include a position sensor and/or a minute ventilation (MV) sensor to sense minute ventilation, which is defined as the total volume of air that moves in and out of a patient's lungs in a minute. Signals generated by the position sensor and MV sensor are passed to the microcontroller 220 for analysis in determining whether to adjust the pacing rate, etc. The microcontroller 220 monitors the signals for indications of the patient's position and activity status, such as whether the patient is climbing upstairs or descending downstairs or whether the patient is sitting up after lying down.

The stimulation device additionally includes a battery 276 that provides operating power to all of the circuits shown in FIG. 2, as well as to any additional circuits which may be present in alternative embodiments. Operating power in the form of electrical current and/or voltage may be provided via a power bus or power buses 294, depicted in FIG. 2 as a first power bus 294.1 and a second power bus 294.2. In FIG. 2, the connection(s) of power bus(es) 294 to other elements of ICTD 100 for purposes of powering those elements is not illustrated, but is implied by the dotted end-lines of bus( es) 294.

For the stimulation device 100, which employs shocking therapy, the battery 276 is capable of operating at low current drains for long periods of time (e.g., preferably less than 10 flA), and is capable of providing high-current pulses (for capacitor charging) when the patient requires a shock pulse (e.g., preferably, in excess of 2 Amps, at voltages above 2 volts, for periods of 10 seconds or more). In an embodiment, battery 276 may be configured to provide a current as high as 3.5 to 4.5 Amps and/or unloaded voltages in excess of 4 volts, for rapid charging of shocking circuitry. Battery 276 also desirably has a predictable discharge characteristic so that elective replacement time can be determined.

In an embodiment, battery 276 may be a hybrid battery comprised of dual types of cells. Such a hybrid battery may provide power via a plurality of power buses, such as buses 249.1 and 294.2 ofFIG. 2. In an embodiment, each power bus may be configured to deliver different voltages, different currents, and/or different power levels. Battery 276 may be monitored and/or controlled via battery control 286, as discussed in part above, and as also discussed further below.

The stimulation device 100 can further include magnet detection circuitry (not shown), coupled to the microcontroller 220, to detect when a magnet is placed over the stimulation device 100. A magnet may be used by a clinician to perform various test functions of the stimulation device 100 and/ or to signal the microcontroller 220 that the external programmer 254 is in place to receive or transmit data to the microcontroller 220 through the telemetry circuit 264.

The stimulation device 100 further includes an impedance measuring circuit 278 that is enabled by the microcontroller 220 via a control signal 280. The known uses for an impedance measuring circuit 278 include, but are not limited to, lead impedance surveillance during the acute and chronic phases for proper lead positioning or dislodgement; detecting

14 operable electrodes and automatically switching to an operable pair if dislodgement occurs; measuring respiration or minute ventilation; measuring thoracic impedance for determining shock thresholds; detecting when the device has been implanted; measuring stroke volume; and detecting the opening ofheart valves, etc. The impedance measuring circuit 278 is advantageously coupled to the switch 226 so that any desired electrode may be used.

In the case where the stimulation device 100 is intended to 10 operate as an implantable cardioverter/defibrillator (ICTD)

device, it detects the occurrence of an arrhythmia, and automatically applies an appropriate therapy to the heart aimed at terminating the detected arrhythmia. To this end, the microcontroller 220 further controls a shocking circuit 282 by way

15 of a control signal 284. The shocking circuit 282 generates shocking pulses of low (e.g., up to approximately 0.5 J), moderate (e.g., approximately 0.5 J to approximately 10 J), or high energy (e.g., approximately 11 J to approximately 40 J), as controlled by the microcontroller 220. Such shocking

20 pulses are applied to the patient's heart 102 through at least two shocking electrodes, and as shown in this embodiment, selected from the left atrial coil electrode 126, the RV coil electrode 132, and/or the SVC coil electrode 134. As noted above, the housing 200 may act as an active electrode in

25 combination with the RV coil electrode 132, or as part of a split electrical vector using the SVC coil electrode 134 or the left atrial coil electrode 126 (i.e., using the RV electrode as a common electrode). Other exemplary devices may include one or more other coil electrodes or suitable shock electrodes

30 (e.g., a LV coil, etc.). Shocking circuit 282 either has within it, or is coupled to,

one or more shocking capacitors (not shown in FIG. 2). The shocking capacitor(s) may be used to store up energy, and then release that energy, during the generation of shocking

35 pulses. Cardioversion level shocks are generally considered to be

of low to moderate energy level (where possible, so as to minimize pain felt by the patient), and/or synchronized with an R-wave and/or pertaining to the treatment of tachycardia.

40 Defibrillation shocks are generally of moderate to high energy level (i.e., corresponding to thresholds in the range of approximately 5 J to approximately 40 J), delivered asynchronously (since R-waves may be too disorganized), and pertaining exclusively to the treatment of fibrillation. Accord-

45 ingly, microcontroller 220 is capable of controlling the synchronous or asynchronous delivery of the shocking pulses. ICTD Progrmer

As indicated above, the operating parameters of the implantable device 100 may be non-invasively programmed

50 into the memory 260 through a telemetry circuit 264 in telemetric communication via communication link 266 with the external device 254. The external device 254 may be a general purpose computer running custom software for programming the ICTD 100, a dedicated external progrmer device of

55 ICTD 100, a transtelephonic transceiver, or a diagnostic system analyzer. Generically, all such devices may be understood as embodying computers, computational devices, or computational systems with supporting hardware or software which enable interaction with, data reception from, and pro-

60 gramming ofiCTD 100. Throughout this document, where a person is intended to

program or monitor ICTD 100 (where such person is typically a physician or other medical professional or clinician), the person is always referred to as a "human progrmer" or

65 as a "user". The term "human programmer" may be viewed as synonymous with "a person who is a user of an ICTD programming device", or simply with a "user". Any other refer-


US 8,108,053 B2 15

ence to "progrannner" or similar terms, such as "ICTD progrannner", "external progrannner", "progrannning device", etc., refers specifically to the hardware, firmware, software, and/or physical connnunications links used to interface with and program ICTD 100.

The terms "computer program", "computer code", and "computer control logic" are generally used synonymously and interchangeably in this document to refer to the instructions or code which control the behavior of a computational system. The term "software" may be employed as well, it being understood however that the associated code may in some embodiments be implemented via firmware or hardware, rather than as software in the strict sense of the term (e.g., as computer code stored on a removable medium, or transferred via a network connection, etc.).

A "computer program product" or "computational system program product" is a medium (for example, a magnetic disk drive, magnetic tape, optical disk (e.g., CD, DVD), firmware, ROM, PROM, flash memory, a network connection to a server from which software may be downloaded, etc) which is suitable for use in a computer or computation system, or suitable for input into a computer or computational system, where the medium has control logic stored therein for causing a processor of the computational system to execute computer code or a computer program. Such medium, also referred to as "computer program medium", "computer usable medium", and "computational system usable medium", are discussed further below.

FIG. 3 presents a system diagram representing an exemplary computer, computational system, or other programming device, which will be referred to for convenience as ICTD programmer 254. It will be understood that while the device is referred to an "ICTD progrannner", indicating that the device may send progrannning data, programming instructions, progrannning code, and/or programming parameters to ICTD 100, the ICTD progrannner 254 may receive data from ICTD 100 as well, and may display the received data in a variety of formats, analyze the received data, store the received data in a variety of formats, transmit the received data to other computer systems or technologies, and perform other tasks related to operational and/or physiologic data received from ICTD 100.

ICTD progrannner 254 includes one or more processors, such as processor 304. Processor 304 is used for standard computational tasks well known in the art, such as retrieving instructions from a memory, processing the instructions, receiving data from memory, performing calculations and analyses on the data in accordance with the previously indicated instructions, storing the results of calculations back to memory, programming other internal devices within ICTD progrannner 254, and transmitting data to and receiving data from various external devices such as ICTD 100.

Processor 304 is connected to a connnunication infrastructure 306 which is typically an internal connnunications bus of ICTD programmer 254; however, ifiCTD progrannner254 is implemented in whole or in part as a distributed system, communication infrastructure 306 may further include or may be a network connection.

ICTD programmer 254 may include a display interface 302 that forwards graphics, text, and other data from the connnunication infrastructure 3 06 (or from a frame buffer not shown) for display on a display unit 330. The display unit may be, for example, a CRT, an LCD, or some other display device. Display unit 330 may also be more generally understood as any device which may convey data to a human programmer.

Display unit 330 may also be used to present a user interface which displays internal features of, operating modes or

16 parameters of, or data from ICTD 100. The user interface presented via display unit 330 ofiCTD programmer 254 may include various options that may be selected, deselected, or otherwise changed or modified by a human programmer of ICTD 100. The options for programming the ICTD 100 may be presented to the human progrannner via the user interface in the form of buttons, check boxes, menu options, dialog boxes, text entry fields, or other icons or means of visual display well known in the art.

10 ICTD programmer 254 may include a data entry interface 342 that accepts data entry from a human programmer via data entry devices 340. Such data entry devices 340 may include, for example and without limitation, a keyboard, a

15 mouse, a touchpad, a touch-sensitive screen, a microphone for voice input, or other means of data entry, which the human progrannner uses in conjunction with display unit 330 in a manner well known in the art. For example, either a mouse or keystrokes entered on a keyboard may be used to select check

20 boxes, option buttons, menu items, or other display elements indicating human progrannner choices for programming ICTD 100. Direct text entry may be employed as well. Data entry device 340 may also take other forms, such as a dedicated control panel with specialized buttons and/or other

25 mechanical elements or tactile sensitive elements for progrannning ICTD 100.

Display interface 302 may present on display unit 330 a variety of data related to patient cardiac function and performance, and also data related to the present operating mode,

30 operational state, or operating parameters of ICTD 100. Modifications to ICTD 100 operational state(s) may be accepted via data entry interface 342 and data entry device 340. In general, any interface means which enables a human progrannner to interact with and program ICTD 100 may be

35 employed. In one embodiment, for example, a visual data display may be combined with tactile data entry via a touchscreen display.

In another embodiment, a system of auditory output (such as a speaker or headset and suitable output port for same, not

40 shown) may be employed to output data relayed from ICTD 100, and a system of verbal input (such as a microphone and suitable microphone port, not shown) may be employed to program ICTD 100. Other modes of input and output means may be employed as well including, for example and without

45 limitation, a remote interaction with ICTD 100, viewing printed data which has been downloaded from ICTD 100, or the progrannning of ICTD 100 via a previously coded program script.

All such means of receiving data from ICTD 100 and/or 50 progrannning ICTD 100 constitute an interface 302, 330,

342, 340 between ICTD 100 and a human programmer of ICTD 100, where the interface is enabled via both the input/ output hardware (e.g., display screen, mouse, keyboard, touchscreen, speakers, microphone, input/output ports, etc.)

55 and the hardware, firmware, and/or software of ICTD progrannner 254.

ICTD progrannner 254 also includes a main memory 308, preferably random access memory (RAM), and may also include a secondary memory 310. The secondary memory

60 310 may include, for example, a hard disk drive 312 and/or a removable storage drive 314, representing a floppy disk drive, a magnetic tape drive, an optical disk drive, etc. The removable storage drive 314 reads from and/or writes to a removable storage unit 318 in a well known manner. Removable

65 storage unit 318 represents a magnetic disk, magnetic tape, optical disk, etc. which is read by and written to by removable storage drive 314. As will be appreciated, the removable


US 8,108,053 B2 17

storage unit 318 includes a computer usable storage medium having stored therein computer software and/or data.

In alternative embodiments, secondary memory 310 may include other similar devices for allowing computer programs or other instructions to be loaded into I CTD programmer 254. Such devices may include, for example, a removable storage unit 322 and an interface 320. Examples of such may include a program cartridge and cartridge interface (such as that found in video game devices), a removable memory chip (such as an erasable programmable read only memory 10

(EPROM), programmable read only memory (PROM), or flash memory) and associated socket, and other removable storage units 322 and interfaces 320, which allow software and data to be transferred from the removable storage unit 322 to ICTD programmer 254. 15

ICTD programmer 254 also contains a communications link 266 to ICTD 100, which may be comprised in part of a dedicated port of ICTD programmer 254. From the perspective ofiCTD programmer 254, communications link 266 may also be viewed as an ICTD interface. Communications link 20

266 enables two-way communications of data between ICTD programmer 254 and ICTD 100. Communications link 266 has been discussed above (see the discussion of FIG. 2A).

ICTD programmer 254 may also include a communications interface 324. Communications interface 324 allows 25

software and data to be transferred between ICTD programmer 254 and other external devices (apart from ICTD 100). Examples of communications interface 324 may include a modem, a network interface (such as an Ethernet card), a communications port, a Personal Computer Memory Card 30

International Association (PCMCIA) slot and card, a USB port, an IEEE 1394 (FireWire) port, etc. Software and data transferred via communications interface 324 are in the form of signals 328 which may be electronic, electromagnetic, optical (e.g., infrared) or other signals capable of being 35

received by communications interface 324. These signals 328 are provided to communications interface 324 via a communications path (e.g., cham1el) 326. This cham1el 326 carries signals 328 and may be implemented using wire or cable, fiber optics, a telephone line, a cellular link, an radio fre- 40

quency (RF) link, in infrared link, and other communications channels.

18 able storage drive 314, hard drive 312, secondary memory interface 320, or communications interface 324.

DEFINITIONS

Below are definitions of some of the terms employed in this document.

It should be understood that various terms, such as "lead," "cable," "conductor," "filament," "wire," "cable-layer," and similar terms may be used or employed variously among persons skilled in the relevant arts. Related, similar, or par-tially similar elements used elsewhere in the art may be named or described differently and with different terms in other documents.

Lead: Also known as a cardiac lead. An elongated, flexible tubular element, commonly though not necessarily with a circular cross-section orthogonal to the axis of elongation. A lead is composed of one or more cables, and a sheath which houses the cables, as defined further below. A lead has a proximal end and a distal end. The proximal end of the lead is designed to attach to an ICTD or other therapeutic or sensing device. The distal end of the lead is designed to have one or more elements for attaching the lead to organic tissue (e.g., fixing tines), and/or electrode elements for delivery of electricity to organic tissue (typically for therapeutic purposes), and/or other elements for delivery of other therapeutic treat-ments to organic tissue, and/or elements for sensing an activity of organic tissue.

In some cases, the attaching element( s) may be the same as the electrode(s), other therapeutic delivery element(s), or sensing element(s). In some cases, elements for attaching to organic tissue, for delivery of electricity, for delivery of other therapeutic treatments, or for sensing may also be placed at one or more points intermediate between the proximal end and the distal end. Suitable alterations, such as placement of punctures or holes, made be made to the sheath (defined below) and to other jacketing, coating, or insulation (defined below) to enable suitable mechanical and/or electrical connectivity between these intermediate elements and the interior electrically conducting cables and/or other interior therapeutic delivery pathways of the lead. Exemplary leads are illustrated in FIGS. 4, discussed below.

Sheath: The body is a typically non-conducting element of a lead which provides the exterior insulation of the lead and

The terms "computer program medium", "computer usable medium", and "computational system usable medium" are used, synonymously, to generally refer to media such as removable storage drive 314 and removable storage unit 381, a hard disk installed in hard disk drive 312, a secondary memory interface (such as a flash memory port, USB port, FireWire port, etc.) and removable storage unit 322 (such as flash memory), and removable storage units 318 and 322. These computer program products or computational system program products provide software to ICTD programmer 254.

45 may also provide interior separation and/or insulation between two or more conducting cables (as defined below) if multiple cables are employed within the lead. The sheath typically extends the full length or almost the full length of the lead, possibly excluding the length of the proximal and distal

It should be noted, however, that it is not necessarily the case that the necessary software, computer code, or computer program (any of which may also referred to as computer control logic) be loaded into ICTD programmer 254 via a removable storage medium. Such computer program may be loaded into ICTD programmer 254 via communications link 328, or may be stored in memory 308 ofiCTD programmer 254. Computer programs are stored in main memory 308 and/ or secondary memory 310. Computer programs may also be received via communications interface 324.

Accordingly, such computer programs represent controllers of ICTD programmer 254, and thereby controllers of ICTD 100. Software may be stored in a computer program product and loaded into ICTD programmer 254 using remov-

50 end elements (for attaching to the ICTD, end electrodes, etc.) As will be understood by persons skilled in the relevant arts, the sheath of a lead may have multiple layers, for example an inner insulating sheath and an outermost sheath. The sheath may be made from any number of materials which demon-

55 strate resilience and flexibility including, for example and without limitation, silicone rubber, polyurethane, Optim® (a silicone-polyurethane co-polymer insulation), PTFE (polytetrafluoroethylene ), or ETFE ( ethylene-tetrafluoroethylene ), polyimide, paryline, PFA, etc. Exemplary sheaths are illus-

60 trated in FIGS. 4, discussed below. Lumen: The sheath provides one or more hollow, mutually

insulated interior canals or tubular spaces known as "lumens," running substantially parallel to the outer wall of the sheath, which typically run the full length of the sheath. The lumens

65 are designed to provide a pathway for one or more electrically conducting cables and/or coil conductors for delivery of therapeutic treatments or for sensing, or pathways for deliv-


US 8,108,053 B2 19

ery of other therapeutic treatments. One or more lumens may also be designed to accommodate a stylet or wire guide, etc. Exemplary lumens are illustrated in FIGS. 4, discussed below.

20 below, there may be several filaments in a cable-layer. In an alternative embodiment, a cable-layer may have only a single filament.

Filament (or synonymously in this document, a Wire): A filament or wire is a single, mechanically unitary thread of conducting material. While mechanically unitary, a filament may be composed of multiple materials, possibly in separate layers which are bonded to each other. For example, a filament may have an inner core of a first metal or metal alloy and

Multilumen: When an element has two or more lumens running through it, these may be referred to together as a multilumen. In this document, the term "lumen" may sometimes be used in place of "multilumen" where the context makes clear the meaning, or where either a lumen (single canal) or multilumen may be intended. 10 an outer tube of a second metal or metal alloy, with the layers

bonded to each other. Additional layers, and other composite arrangements of bonded, electrically conductive materials, may be possible as well. A filament typically maintains a substantially consistent cross-sectional shape and size for its

Cable: A cable is an electrically conducting element made from a conducting material (including for example and without limitation silver, copper, nickel, chromium, aluminum, iron, molybdenum, etc., and/or various alloys of these metals and other metals), typically running the full length or substantially the full length of an ICTD lead. The conducting elements of a cable (central core, cable-layers, and filaments, defined further below) are also composed of conducting elements (including for example and without limitation silver, 20

copper, nickel, chromium, aluminum, iron, molybdenum, etc., and/or various alloys of these metals and other metals ).A cable may also have within it non-conducting materials and/

15 entire length. The cross-sectional shape may be substantially round or substantially oval, or may be other shapes, as discussed further below. The cross-sectional size may vary depending on the application or placement in the cable. A

or coatings, as discussed further below. A cable is typically dedicated to, and designed for, carrying 25

a single type of electrical signal or therapeutic electricity. For example, a cable may be dedicated to right ventricular (RV) shocking, or to superior vena cava (SVC) shocking, or to sensing cardiac activity. In some cases, a cable may be configured for dual purposes (for example, shocking and sens- 30

in g), but will typically still be configured to carry only a single electrical signal at a time (for example, either a shocking charge or a sensing signal). Functionally, a cable is equivalent to what may be conventionally viewed as a single conductor or single wire carrying electricity. However, as discussed 35

immediately below, a cable may actually be comprised of multiple filaments of electrically conductive material. At the proximal end, the cable may include means for connection with the ICTD or other therapeutic device, and at the distal end may be an electrode or other element for delivery of 40

therapeutic treatment or for sensing purposes. Other elements may be attached between the proximal and distal ends, connected to the cable via holes in the lumen.

It is noted here that the design of an improved cable for ICTD leads is an advantage of the present cable and lead 45

designs. A cable may be a single conductive element (conventionally referred to as a "solid wire"). However, a cable may also be made of multiple conducting elements as defined briefly here, and discussed further in greater detail, below. These elements may include a central core, and layers which 50

are further comprised of filaments. Exemplary cables and their elements are illustrated in

FIGS. 5-10, discussed further below. Central Core: A central core is a continuous conducting

element of a cable which runs substantially down the geomet- 55

ric center of the cable. In one embodiment of the present cable and lead designs, the central core may be a single filament (defined below). In an alternative embodiment, the central core may be comprised of multiple filaments.

Cable-layer: A cable-layer is a conducting element of a 60

cable which is exterior to the central core. A cable-layer may be wound around the central core. A cable-layer may be composed of one or more conducting filaments (defined below) which may be wound together in parallel, braided together, or otherwise be mechanically coupled to or imme- 65

diately adjacent to each other. In an embodiment of the present cable and lead designs, and as discussed further

filament is also sometimes known in the art as a "filar." Strand: A strand is an element of a cable in which multiple

filaments are wound together, typically in a helical or spiral fashion. A strand may have multiple strand layers. Multiple strands may be wound together or otherwise conjoined to form a cable.

In embodiments of the present cable and lead designs illustrated below as exemplary cables 600, 700, 800, and 900 (see FIGS. 6-9), these exemplary cables have only a single strand (with multiple cable-layers, each layer having multiple filaments). In these single-strand embodiments, the "cable" and the "strand" are essentially one in the same, and only the term "cable" is employed.

However, and as illustrated with exemplary rope cable 1100 (see FIG. 11), a cable may have multiple strands. As discussed in further detail below, the elements of the present cable and lead designs may be advantageously employed both in cables with a single strand, and in cables with multiple strands.

A common notation used to describe cables employs the measurements "SxF", where "S" is the number of strands and "F" is the number of filaments. For example, a "1x19" cable has 1 strand with 19 filaments (possibly in two or more cable-layers). A "7x7" cable has 7 strands with 7 filaments per strand.

Jacket (or synonymously in this document, a Coating, Insulation): A jacket or coating is typically a non-conducting material which may be placed around or in contact with a filament, a cable-layer, or the central core.

Dual Cable: The delivery of some therapeutic treatments, or the sensing of some signals, may require more than one cable. For example, two cables may be required to deliver cardiac shocking therapy. Two cables may be placed in par-allel within an insulating material, and the two cables may be placed within a single canal within the lumen of the cardiac lead. The dual cables may or may not be separated by their own insulating material.

Coil: A coil is another type of electrically conducting element, typically running the full length or substantially the full length of an ICTD lead. An example is a pacing coil. In a coil, the conducting material is actually coiled or tightly wound, providing additional stiffness. Unless specifically noted otherwise, the conductor cables for small caliber ICTD leads described in detail below are not coils.

Conducting Material: As noted above, a conducting material is any electrically conducting material, including for example and without limitation silver, copper, nickel, chromium, aluminum, iron, molybdenum, tin, platinum, gold, cobalt, tungsten, etc., and/or various alloys of these metals


US 8,108,053 B2 21

and other metals. Conducting materials may not be limited exclusively to metals, however. For example, a metal alloy with some non-metallic elements (e.g., carbon) may also be an electrically conducting material. Implantable Leads

The present cable and lead designs are directed towards cable conductors for use in implantable medical leads, such as medical leads used in ICTD device implantation as discussed above with reference to FIG. 1. Exemplary leads 104, 106, 108, 110 may be structurally the same as or similar to ex em- 1 o plary leads 400, 420 discussed in this section with respect to FIGS. 4. Exemplary leads 104, 106, 108, 100 may advantageously employ combinations of elements presented in conjunction with exemplary leads 400, 420 discussed in this section with respect to FIGS. 4. Similarly, exemplary leads 15

400, 420, as well as leads which may be structurally the same

22 and lead designs, as discussed in further detail below. Such cables have, for example, an outer diameter of0.007" (i.e., 7 mils).

FIG. 4E illustrates in cross-section another exemplary implantable ICTD lead 420 according to an embodiment of the present cable and lead designs. Exemplary lead 420 is configured for use with the exemplary reduced diameter conducting cables 600, 700, 800, 900, as well as other cables falling within the scope and spirit of the present cable and lead designs, as discussed in further detail below.

Lead 420 has four lumens: lumen 410A configured for SVC shocking; lumen 410B configured for a pacing coil with stylet; lumen 410C for RV shocking; and lumen 410D configured for a sensing cable. Lumen 41 OA and lumen 41 OB are designed to hold single cables. In addition all four lumens 410 have liners 415. Notable in FIG. 4E is that lumens 410a and 410c configured to receive cables for cardiac shocking are configured to receive only a single cable. The improved cable conductor designs are configured so that shocking currents

as, similar to, and/or advantageously employ combinations of elements discussed with respect to exemplary leads 400, 420, may be employed in a variety of implantable biomedical applications and other applications as well.

FIG. 4A illustrates an exemplary implantable ICTD lead 400 according to an embodiment of the present cable and lead designs. Lead 400 may for example be suitable for use as any

20 may be carried over a single cable, rather than two cables as is required in existing designs.

of leads 104, 106, 108, or 110 already discussed above in conjunction with FIG. 1.

FIG. 4F is another cross-sectional view of the exemplary lead 420 shown in FIG. 4E. FIG. 4F displays exemplary measurements of the various elements such as sheath 405,

25 lumens 410, and liners 415. Persons skilled in the relevant arts will appreciate that the

views of exemplary leads shown in FIGS. 4A-4F represent cross-sectional views only. Orthogonal to the cross-sectional views shown are the lengths of the leads, which are elongated flexible tubular elements, wherein the lumens are configured to receive such elements as cables, coils, or stylets. Cables and coils are used for such purposes as conducting electrical signals or electrical impulses for cardiac sensing and cardiac shocking.

Lead 400 has a sheath 405, and five lumens 410a, 410b, 410c, 410d, and 410e. Lumen 410a is a dual lumen configured to contain shocking cables for superior vena cava (SVC) shocking. Lumen 410b is a lumen configured to contain a stylet. Lumen 410c is a dual lumen configured to contain dual 30

cables for right ventricular (RV) shocking. Lumen 410d is configured to contain a single sensing cable to sense cardiac activity. Lumen 410e is configured to contain a pacing coil. Exemplary cables and their elements are discussed further below with respect to FIGS. 5-10. 35 Cables Used in Leads, Fretting Fatigue and Failure Modes in

the Cables In one embodiment of the present cable and lead designs there is no liner in the cable lumens. In an alternative embodiment a liner is used in the cable lumens. In an embodiment of the present cable and lead designs the sheath is made from ethylene-tetrafluoroethylene (ETFE).

FIG. SA illustrates an exemplary cable 500. Exemplary cable 500 has a central wire (or core) 505 which, in an embodiment, is a single wire or filament of a conducting

Persons skilled in the relevant arts will appreciate that lead 400 is exemplary only. The number of lumens shown, the construction of the lumens, the choice of lumens for single cables or double cables, the spacing between the lumens, the application of the lumens for sensing, pacing, shocking, or for a stylet or other stearable elements, are all exemplary. Fewer or more lumens and different configurations oflumens within the lead may be employed within the spirit and scope of the present cable and lead designs.

40 material, such as a metal or a metal alloy. In an alternative embodiment, the central core may actually be comprised of multiple filaments which are wound together or otherwise mechanically coupled (not shown in FIG. SA).

Surrounding central wire 505 is a cable-layer such as 45 cable-layer 510.i which is an inner cable-layer, and which is

composed of multiple filaments 515. The filaments 515 of cable-layer 510.i are wound around central core 505 in a helical fashion.

FIGS. 4B, 4C, and 4D present additional cross-sectional 50

views of the exemplary lead 400 shown in FIG. 4A. The views in FIGS. 4B, 4C, and 4D shows exemplary measurements of elements oflead 400. In FIGS. 4B, 4C, 4D, and also FIG. 4F discussed below, distance measurements are in units of inches, angles are in degrees, R =radius, 0=diameter. Persons 55

skilled in the relevant arts will appreciate that the measurements shown are exemplary only. Leads with other measurements of elements, such as measurements of the sheath, or measurements of the size and spacing of the lumens, may be employed within the scope and spirit of the present cable and 60

lead designs. Existing cables for cardiac sensing and/or shocking have,

for example, exterior diameters of 0.009" or 0.008", and would not fit within the lumens of lead 400. Exemplary lead 400 is configured for use with the exemplary reduced diam- 65

eter conducting cables 600, 700, 800, 900, as well as other cables falling within the scope and spirit of the present cable

Surrounding inner cable-layer 510.i is a second cablelayer, namely a middle cable-layer 51 O.m, which is also composed of multiple filaments 515. Filaments 515 of cable-layer 510.m are wound around cable-layer 510.i, again in a helical fashion. Surrounding middle cable-layer 510.m is outer cable-layer 510.o which again is composed of multiple fila-ments 515, this time wound helically around middle cablelayer 510.m.

It will be noted in FIG. SA that filaments 515 have a substantially circular cross-section as is commonly found in the art. Likewise, central core 505 has a substantially circular cross-section.

Cable-layers 510, and more specifically the filaments 515 of a cable-layer 510, may be wound with a helical or spiral winding around the element inner to them, such as an inner cable-layer 510.i or central wire 505. Persons skilled in the relevant arts will appreciate that the configuration of central wire 515, inner cable-layer 510.i, middle cable-layer 510.m, and outer cable-layer 510.o shown in FIG. SA is exemplary


US 8,108,053 B2 23

only. Fewer cable-layers, more cable-layers, fewer filaments, or more filaments may be employed.

24 mode and Trellis contact mode at respective contact lines/ points 555 or 565 between cable-layers 515 are locations where fretting fatigue may occur. FIG. SB is a partial cross-sectional view of the cable 500

shown in FIG. SA. The cross-sectional view shows middle cable-layer 510.m, inner cable-layer 510.i, and central wire 505. (Outer cable-layer 510.o is omitted.) Also shown are points of contact, and therefore points of pressure, between filaments 515 of the cable-layers. For example points of contact 'A' exist between filament 515.1 and 515.2 of middle cable-layer 510.m. Points of contact 'B' also exist between filament 515.3 of inner cable-layer 510.i and filament 515.1 of middle cable-layer 510.m. Not shown, but present in cable 500, is contact and pressure between filaments 515 of inner cable-layer 510.i and central wire 505.

Fretting fatigue is a wear phenomenon occurring between two surfaces having oscillatory relative motion of small amplitude. Fretting is generally associated with contact surfaces which are held together in some manner, often by a mechanical connection (such as clamping, or elements which are twisted or crimped together) and where the surfaces in

10 contact are nominally at rest. Put another way, while there is relative motion between the elements making contact, the body which contains them as a whole may be in a substantially static, global equilibrium. At the same time, the ele-

15 ments in contact experience some small-scale, relative oscillatory or vibratory motion.

Because filaments 515 in a common cable-layer 510 typically are configured to run in parallel to each other, there is a substantially continuous line of contact between adjacent filaments. FIG. SC illustrates a line of contact 555 between two filaments 515.1 and 515.2 of middle cable-layer 510.m (see FIG. SB). The direction of force or pressure between 20

filaments 515.1, 515.2 is indicated by arrows A, consistent with pressure indicated by arrows A in FIG. SB. While contact between filaments 515.1 and 515.2 is illustrated as line 555, persons skilled in the relevant arts will appreciate that compression between filaments 515.1 and 515.2 actually results 25

in a narrow, elongated area of contact 555, which for convenience is referred to a "line of contact."

These conditions occur between the filaments of a cable inside an ICTD lead 400, 420. While lead 400, 420 as a whole may be substantially at rest (relative to a patient's body, or relative to a patient's heart), small but continual sources of movement (such as movement of cardiac muscles, circulation ofblood surrounding the lead, etc.) cause small movements of lead 400, 420. This in tum causes filaments 515 within lead cables 500 to experience small relative motion, and this results in fretting fatigue along line of contact 555 and Trellis contact point 565.

Fretting contact causes detrimental effects since it leads to wear. In addition, tensile stresses from the contact promote crack initiation and propagation. These fatigue cracks can lead to component failure, such as a breaking of filaments 515. Trellis contact mode dominates the fretting fatigue, the key failure mode of a cable, due to the smaller contact area of Trellis contact point 565 relative to line of contact 555, and also due to larger frictional sliding motions that generate larger alternating stresses or strains on the filaments 515 between adjacent cable-layers 510.

In cable-layers 510 which are adjacent to each other or between an inner cable-layer 510.i and the central core 505, filaments 515 are not wound in identically parallel helices. 30

(See again FIG. SA, where filaments 515 of cable-layer 510.o are not wound in parallel to filaments 515 of adjacent cablelayer 510.m, and filaments 515 of cable-layer 510.m are not wound in parallel to cable-layers 515 of adjacent cable-layer 510.i. )As a result, contact between filaments 515 in adjacent 35

cable-layers 510 is made along a small contact area which may be referred to as a point of contact. Also, contact between filaments of an inner cable-layer 510.i and a central core 505 may again be made along a small contact area which may be referred to as a point of contact.

FIG. SD illustrates a contact mode between two filaments 515 of two adjacent cable-layers, which may for example be filament 515.1 of middle cable-layer 510.m and filament 515.3 of inner cable-layer 510.i (see FIG. SB, discussed above). The small area of contact 565 may be referred to as 45

point of contact 565, and is located between the two filaments 515.1, 515.3. (It is illustrated in FIG. SD with a dashed line and a shaded interior to indicate it is actually between the filaments, and not on a surface of filament 515.3 opposite to filament 515.1.) The direction afforce or pressure 'B' at point 50

of contact 565 is into the page from the filament 515.3 illustrated as the top filament, and out of the page from the filament 515.1 illustrated as the bottom filament, and is consistent with pressure indicated by arrows Bin FIG. SB.

Further, fretting fatigue at either line of contact 555 or Trellis contact point 565 is more likely to cause filament failure than stresses internal to filaments 515, since the fila-

40 ment surfaces are where manufacturing defects are most likely to exist.

The reference to filaments as "top" and "bottom" is made 55

with reference to the illustration only, is for convenience of explanation, and is not intended to be limiting. Contact between filaments 515 may occur between filaments within any cable-layer 510, between filaments 515 of any two adjacent cable-layers 510, and between filaments 515 of a cable- 60

layer 510 and central wire 505. The contact point 565 between filaments 515.1 and 515.3

of adjacent cable-layers 510.m and 510.i is referred to as the point of Trellis contact between filaments 515.1 and 515.3. The overall configuration of filaments 515 in adjacent cable- 65

layers 510 pressing against each other at Trellis contact point 565 is referred to as Trellis contact mode. Both line contact

FIG. SE illustrates a typical fretting fatigue fracture mor-phology of a fine wire filament of a cable subjected to cyclic flex loading. The view shown is a cross-sectional view of a filament 515. Filament 515 has a fatigue life which may be measured in terms of stress cycles, representing a number of vibrations or cyclic stress pressures that filament 515 can experience before undergoing physical fracture. For example, the fatigue life may be on the order of 100,000,000 cycles.

If filament 515 consistently experiences pressure, stresses, and/or vibrations at a consistent point and in a consistent direction, as represented for example by pressure arrow 526, then filament 515 will have a fatigue zone 520 extended from the point of contact of pressure arrow 526 inward towards the interior of filament 515. Approximately 90% to 99% of the fatigue life of filament 515 is absorbed in fatigue zone 520. When pressure 526 exceeds a fatigue threshold (which may vary depending on the materials and configuration of filament 516), fatigue zone 520 experiences progressive inward degradation, represented by fatigue lines 527. That is, damage to filament 515 propagates inward over time, with repeated stresses and vibrations on the surface of filament 515.

Fast fracture zone 525 takes approximately 10% or less of the total fatigue life. However, when the fatigue caused by pressure or force 526 reaches fast fracture zone 525, filament 515 has a high likelihood of experiencing fracture, that is, a complete break of the filament.


US 8,108,053 B2 25

It is an advantage of the present cable and lead designs to modifY both the structure of filament 515 and the interaction

26

of filament 515 with the surrounding environment, such that pressure 526 on filament is less likely to reach the fatigue threshold. If the fatigue threshold is not reached, cycles of the fatigue life are not used up, and filament 515 is much less likely to experience fracture, or at least is likely to have a greatly prolonged life before fracture. The various elements disclosed in detail below may reduce the pressure experienced by filament 515 by anywhere from 30% to 90% lower 10

as compared with existing designs.

Additional features described in this section and succeeding sections in general terms may also be represented by exemplary embodiments discussed later in this document. Suitable labels will be presented, and will be understood with references to various figures as indicated.

It will be understood by persons skilled in the relevant arts that cables 600/900 may have some elements in common with cables 500 discussed above, along with various distinguishing elements and advantages. Similarly, it will be understood that filaments 615/915 may have some elements in common with filaments 515 already discussed above, along with vari-

Cable Designs for Reduced Diameter with Optimized Mechanical and Electrical Properties-Overview

The structural features of the conductor cables of the 15

ous distinguishing features. Similarly, it will be understood that cable-layers 610/910 may have some elements in common with cable-layers 510 already discussed above, along with various distinguishing features. present cable and lead designs are discussed in detail below in

a later section with respect to FIGS. 6-10, and corresponding exemplary cables 600, 700, 800, and 900 (discussed in respective FIGS. 6, 7, 8, and 9, as well is in FIG.10). In some of the discussion below, and for convenience of reference only, these exemplary cables 600, 700, 800, 900 are referred to collectively herein as cables 600/900. It will be understood that not all the features listed here will necessarily be employed in each of exemplary cables 600/900, and further that other embodiments of the present cable and lead designs, apart from exemplary cables 600/900, and employing some or all of the elements listed in this section, will fall within the scope of the present cable and lead designs. Thus, references below to "exemplary cables 600/900" should be understood to include not only exemplary cables 600, 700, 800, and 900, but all embodiments which may employ, in various combinations, the elements and advantages described herein.

Similarly, exemplary filaments 615, 715, 815, and 915 which may have oval cross-sections and/or other distinguishing features are described in detail below with reference to FIGS. 6-10. These exemplary embodiments, as well as other filaments with oval cross-sections or other distinguishing features falling within the scope of the present cable and lead designs, are referred to collectively herein for brevity as filaments 615/915. Here again it will be understood that not all the features listed here will necessarily be employed in each of exemplary filaments 615/915, and further that other embodiments of the present cable and lead designs, apart from exemplary filaments 615/915, and employing the features and advantages discussed below, will fall within the scope of the present cable and lead designs. Thus, references to "exemplary filaments 615/915" should be understood to include not only exemplary filaments 615, 715, 815, and 915, but all embodiments which may employ, in various combinations, the features described herein.

Similarly, exemplary cable-layers with filaments 615/915 and/or other distinguishing features 610, 710, 810, and 910 are described in detail below with reference to FIGS. 6-9. These exemplary embodiments, as well as other cable-layers falling within the scope of the present cable and lead designs, are referred to herein for brevity as cable-layers 610/910. Here again it will be understood that not all the elements and advantages described herein will necessarily be employed in each of exemplary cable-layers 610/910, and further that other embodiments of the present cable and lead designs, apart from exemplary cable-layers 610/910, and employing the elements and advantages listed herein, will fall within the scope of the present cable and lead designs. Thus, references to "exemplary cable-layers 610/91 0" should be understood to include not only exemplary cable-layers 610, 710, 810, and 910, but to all embodiments which may employ, in various combinations, the features and advantages described herein.

The features of the conductor cables 600/900 of small caliber ICTD leads 400, 420 of the present cable and lead designs are discussed here. These features make it possible to

20 employ these conductor cables 600/900 with all types ofiCD, CRT, and Brady leads 400, 420 for active or passive fixation. Cable Designs Overview-Mechanical and Structural Elements

The mechanical performance of the conductor cables 600/ 25 900 (discussed in specific detail below with respect to FIGS.

6-1 0) is optimized with respect to currently existing cables to have higher tensile strength (approximately three to six lbs.), less flex/bending stiffness, lower fretting fatigue failure risk, and lower chance of failure due to kinking and bird-caging.

30 This advantageous mechanical performance is achieved via a variety of elements, used alone or in various combinations, including, for example and without limitation:

A. The use of filaments 615/815 with substantially oval cross-sections as the cable filaments. (It is noted here that

35 exemplary filament 915, discussed in connection with exemplary cable 900 of FIG. 9, does not use an oval cross-section, and instead retains a substantially circular cross-section. Hence reference is made here to exemplary filaments 615, 715, and 815, or 615/815, discussed in conjunction with

40 FIGS. 6, 7, 8, and 10.) The oval shape filaments are structurally arranged in a manner which increases the Trellis contact surface areas between cable-layer layers 610/810, which decreases the contact pressure or stress. Therefore, the fretting fatigue failure risk of cables 600/800 is decreased. The

45 stationary oval shape filaments can be wound around a rotating and translating center round wire or around a mandrel for the cables or cable-layers. Filaments with oval cross-sections also offer a larger cross sectional area for a given cable diameter; they therefore have higher tensile strength than the round

50 shape filaments 515 in the traditional cables 500. In an embodiment of the present cable and lead designs, all

the cable-layers employ filaments with substantially ovalcross sections. In an alternative embodiment, some cablelayers employ filaments with substantially oval cross-sec-

55 tions, while some cable-layers employ filaments with substantially circular cross sections or other cross sections.

B. A polymer coating or jacket on the filaments may be placed between cable-layers. This changes the contact interaction mode from hard to soft contact between the filaments,

60 which decreases the contact pressure, and therefore, the fretting fatigue failure risk of the cables.

C. The cross sectional area of the filaments may decrease gradually and progressively from the center wire 605/905, to one or more middle cable-layers 605.m/905.m, and finally to

65 the outer-most cable-layer 605.o/905.o. The result is that the cable 600/900 can offer higher tensile strength but less flex stiffness.


US 8,108,053 B2 27

In an embodiment of the present cable and lead designs, the cross-sectional area decreases progressively with outward radius from the central wire 605/905, with any cable-layer 610/910 having filaments 615/915 of smaller cross-sectional area than the filaments 615/915 of any cable-layer 610/910 or 5

core 605/905 interior to it.

28 cable 600/800 diameter. This results in cable 600/800 having lower DC resistance than the round-shaped filaments 515 in cables 500.

In an alternative embodiment, some adjacent cable-layers 610/910 may have filaments 615/915 of the substantially same cross-sectional area. In an embodiment, a cable 600/900 may have only a central core 605/905 and single cable-layer 610/910 surrounding the central core 605/905, with the filaments 615/915 of the single cable-layer 610/910 having a smaller cross-sectional area than the filament 615/915 of the single core 605/905.

B. For each cable 600/900 within a lead 400, 420, the polymer (ETFE, PTFE, Polyimide, Paryline, PFA, etc.) coatings or jackets 615, 730, 825, 830, 925, 930 on the cable filaments 615/915, or between cable-layers 610/910 (i.e., between layers, or between the central wire 605/905 and the immediately exterior cable-layer 610/910) will insulate the

10 filaments 615/915 within the lead 400, 420 body (i.e., for the length of the lead body). However, the polymer coatings or jackets will be removed (for example, stripped or ablated) at each end of the filaments 615/915 (i.e., at the proximal and

15 distal ends ofleads 400, 420), and for each cable 600/900 the filament 615/915 ends without the insulation materials are D. Varying materials or material strengths (e.g., MP35N,

DFT with different silver content, etc.) may be used for the filaments 615/915 in different cable-layers 610/910 (i.e., different layers). In an embodiment, the strength of the materials decreases from the center wire 605/905 to one or more middle 20

cable-layers 610/910 to the outer cable-layer 610/910, such that the cable 600/900 will offer higher tensile strength but less flex/bending stiffness. This is discussed in further detail with regard to FIG. 10, below.

joined together (see above Mechanical item F) with the pro ximal pin and distal electrode, by means of crimping, for example. The result is that the multiple filaments 615/915 within a cable 600/900 will form parallel circuits in the lead body 400, 420. Such an insulated cable circuit is similar to those in the insulated coils which have been proven, experimentally, to offer lower DC resistance and higher inductance.

E. Proper heat treatment, such as the so-called kill-tern- 25

perature with the wire/cable cold work process, may be employed to provide desired high ductility and high strength

C. Higher silver content DFT filaments may be designed for the cable filaments 615/915, from the current practice of 28% and 31% increasing up to about 50% (see above tensile strength and fatigue performance descriptions), such that the DC resistance can be reduced to approximately 0.6 ohm per foot for cable 600/900. As a result, the single cable's DC

of the wire material, such as MP35N, DFT, etc .. Usually a ductile material offers lower tensile strength; the tensile strength of approximately 4 lb. per cable may be achieved 30

when using the kill-temperature heat treatment for a small size 1 x 19 cable which employs the DFT filaments with silver wire content up to 50%, since most of the wire strength is from the MP35N tube which surrounds the wire's silver core.

35

resistance will be substantially equivalent to the dual cables in some designs of existing ICTD leads, which will maintain a large current carrying capability of up to 50 A as required by the international standard (Section 23.3 of the prEN45502-2-2:2006, Active Implantable Medical Devices, published by the CEN/CENELEC Joint Working Group Active Implantable Medical Devices of the European Committee for Elec-1 x 19 cables with the mechanical design features described

above offer the dimensions of down-sized cables that can meet the requirements for the smaller ICD leads 400, 420 of

trotechnical Standardization). D. With the mechanical features discussed above, it is

possible to wind the filaments 615/915 in each cable-layer 610/910 of a cable 600/900 with a smaller pitch (that is, a steeper degree of inclination or slope) compared to conven-tional cable designs 500. The smaller pitch can be achieved without concerns of increasing the flex stiffness or concerns of higher contact stresses generated in the filaments 615/915

5 French or less. These cable designs can be expanded to other cable structures of single strand cables, such as 1x7, 1x25, 40

and multiple strand cables, such as 7x7. Moreover, a single cable designed with one or more of the above features can replace the dual cables used in some ICTD leads 400 without loss of the pull strength, and at the same time offer less flex stiffness. 45 between layers, since the specific cable structure design fea

tures discussed herein compensate for the smaller pitch. The smaller pitch results in more turns of the cable winding (i.e., more turns of filaments 615/915) for a given lead body length, and so offers a larger inductance. This benefits the low-pass

F. The currently practiced laser welding, crimping, etc. joining technologies for the dual cables in the some ICTD leads can be used for the single cable leads with minor modifications, when the insulation coatings or jackets on the filaments 615/915 or between cable-layers 610/910 are stripped or ablated (such as the soda blast process) at each end of the cable before the joining process. The cable-ring and cableshock coil joining technology would deliver the same joining quality for either the dual or single cable designs. Cable Designs Overview-Electrical and MRI Performance

The electrical and MRI performance of the conductor cables 600/900 is optimized with respect to cables 500 to have a lower, stable DC resistance, good electrical conductivity, higher and stable inductance, and only minor electromagnetic interactions between conductor cables 600/900 and coils. This optimized electrical and MRI performance is achieved via a variety of features, used alone or in various combinations, some of which are the same as the mechanical/structural elements already discussed above, and which may include, for example and without limitation:

A. Oval-shaped cross-sectional filaments 615/815, already discussed above, offer a larger cross section area for a given

50 filter function of cable 600/900, and enhances the MRI radiofrequency (RF) heating reduction, as observed in the MRI scans of coils wound with different pitch lengths.

E. Many existing lead designs require dual cables for such purposes as cardiac shocking. The dual cables in a single

55 lumen are problematic for patients who must undergo MRI tests. The distance between the two conductor cables in a lumen may change any where in the lead body (as the lead is moving or deforming), and consequently the parasitic capacitance along the cables will vary in a large range in a manner

60 difficult to control. This can result in undesirable heating of the cable during an MRI.

The present design enables the substitution of a single cable 600/900 where two cables were previously employed in a single lumen. The single cable can avoid the unstable or

65 non-consistent electromagnetic interactions between the two cables inside the same lumen. This is beneficial for the MRI RF heating reduction.


US 8,108,053 B2 29

Cable Designs Exemplary Embodiments In FIGS. 6-10, where exemplary cables 600/900 are illus

trated in embodiments of the present cable and lead designs, only two cable-layers 610/910 are illustrated exterior to the central wire 605/905. These are referred to as, for example, a 5

"middle cable-layer 610.m" and an "outer cable-layer 610.o. " This is for convenience in labeling only. In these contexts, "middle cable-layer 610.m" could as easily be referred to as "inner cable-layer 610.i." However, the term "middle cablelayer 610.m" is preferred in the sense that, in alternative 10

embodiments, additional middle cable-layers 610.m could be employed (for example, a second middle cable-layer, and/or a third middle cable-layer, etc,), and much of the discussion which pertains to the middle cable-layers illustrated in FIGS. 6-10 could apply to additional middle cable-layers as well. 15

FIG. 6A illustrates an exemplary cable 600 configured for improved mechanical and electrical properties. Cable 600 has

30 this case, as well as in the case of other embodiments of cables discussed below (in conjunction with FIGS. 7-1 0), the contact region between filament 615 and central wire 605 is a medi-ated contact region 603.med which is mediated by a nonconducting coating 615 or other coatings. (See also coatings 730, 825, 830 discussed below in conjunction with FIGS. 7-8.)

However, even with coating 615 or other coatings, the region or area of mediated contact pressure 603 .med is still enlarged relative to that for filaments 515 with strictly circular cross sections (see for example FIG. 5 above). As a result, surface pressure per unit area on filaments 615 or central wire 605 is reduced, and again the reduced pressure per unit area results in decreased fretting fatigue, decreased structural damage to each filament 615, and therefore increased durability and lifetime for cable 600 as a whole

Other advantages of the substantially oval shape of the filaments have already been discussed above, and that discus-

a central wire 605, a middle cable-layer 610.m, an outer cable-layer 610.o, a central wire coating 625, and a cable jacket 620. 20 sian will not be repeated here. A further feature of cross

sectional view of exemplary cable 600 is that the cross-sectional area of a filament 615 decreases progressively along an axial radius from the central core. That is that central core or

Several features of exemplary cable 600 can be immediately observed from FIG. 6A. A first feature is that the filaments 615 of cable-layers 610 have a substantially oval crosssectional shape. That is, exemplary filament 615.m of middle cable-layer 610.m has a substantially oval shape, and exem- 25

plary filament 615.o of outer cable-layer 610.o also has a substantially oval cross-sectional shape. Persons skilled in the relevant arts will appreciate that while the shape illustrated is substantially oval, it is not necessary that the shape of a filament 610 be perfectly ovoid. Filament 615 has two 30

orthogonal axes, both perpendicular to the length of filament 615 (which extends into and out of the page), a first axis of which is substantially longer than a second axis, resulting in

central wire 605 has the largest cross-sectional area. Filaments 605.m of middle cable-layer 61 O.m have a lesser crosssectional area than central wire 605. And similarly filaments 605.o of outer cable-layer 610.o have a substantially smaller cross-sectional area than filaments 615.m of middle cablelayer 610.m. The advantages of reducing the cross-sectional area have already been discussed above and the discussion will not be repeated here.

A further feature of exemplary cable 600 not visible in the figure is that the metallic structure of the filaments 615 may a substantially flattened shape of the filament 615 as com

pared with a circular shape of filament 515 (see FIG. 5). 35 change in going from central wire 605 to middle cable-layer 610.m to outer cable-layer 615.o. A detailed discussion of this change in metallic structure of filaments 615 is provided below, in conjunction with FIG. 10.

It is further to be noted from the figure that the elongated surfaces of filaments 615 in adjacent cable-layers 610 are substantially in contact with one another and substantially parallel to one another. That is, for example, a first flat surface (not shown) which could be placed tangent to an elongated 40

surface of filament 615.m of middle cable-layer 610.m is substantially parallel to a second flat surface (not shown) which could be placed tangent to an elongated surface of filament 615.o of outer cable-layer 610.o. Another way to understand the orientation of oval-cross section filaments 615 45

is to visualize a line 602 extending from the mid-point 601 of

An additional feature of exemplary cable 600 is central wire coating 625. Central wire coating 625 may be comprised of a variety of polymers such as, for example and without limitation, silicone rubber, polyurethane, Optim, PTFE, polyimide, paryline, PFA, etc. Central wire coating 625 further serves to reduce fretting fatigue between middle cable-layer 610.m and central wire 605.

Persons skilled in the relevant arts will appreciate that the exact configuration shown for cable 600 is exemplary only, and in implementation may vary in any number of details. For example, shown in FIG. 6Ais central core 605, middle cable-

an elongated surface of a filament 615, and drawn normal to the elongated surface in the plane of the cross-section. Line 602 will extend towards a point which is in substantial proximity to the geometric center of the cross-sectional area of cable 600. (It should be noted that line 602 is shown for visualization only, and not a structural element of cable 600.)

At locations 603 of parallelism between elongated surfaces of filaments 615.o and 615.m, the surfaces of filaments 615.o and 615.m are in contact. As a result of the contact between these elongated surfaces, the pressure between filaments 615

50 layer 610.m, and outer cable-layer 615.o. More cable-layers or fewer cable-layers may be employed. Similarly, the number of filaments 615 used in each cable-layer is exemplary and may be vary in actual implementation. Similarly, the relative sizes of the filaments 615 are exemplary only and may vary in

55 actual implementation. Similarly, the relative size of cable jacket 620 and central wire coating 625, relative to other elements is exemplary only and may vary in actual implementation.

in adjacent cable-layers 610 is distributed over a wider contact surface area. As a consequence of distributing the pressure between the filaments over a wider contact surface area, the pressure per unit area is reduced on each filament 615. 60

This reduced pressure per unit area results in decreased fretting fatigue, decreased structural damage to each filament 615, and therefore increased durability and lifetime for cable 600 as a whole.

It can be seen from the figure that similar elongated but 65

mediated contact areas 603.med will exist between filaments 615.m of middle cable-layer 610.m and central wire 605. In

FIG. 6B is another view of exemplary cable 600. This view illustrates the extended length of the cable and in addition illustrates the helical winding of filaments 615.o and 615.m.

Also shown in FIG. 6B is that central wire 605 has a 28% silver content. In FIGS. 6C and 6D (discussed further below) it is shown respectively that mid-layer cable-layer 610.m features filaments 615.m with 33% silver content and outer cable-layer 610.o features filaments 615.o with 41% silver content. The amount of silver content is exemplary only, and


US 8,108,053 B2 31

may vary in different embodiments. Further details of the filament metallic structure and content are presented below with respect to FIG. 10.

It is illustrated in FIG. 6B that alternate cable-layers 610 may be wound in alternate directions. For example, middle cable-layer 61 O.m may be left hand wound while outer cablelayer 610.o may be right hand wound. As shown in FIGS. 6C and 6D respectively, the pitch of the winding may vary as well. For example, middle cable-layer 610.m may have a left hand winding with a pitch of0.045 inches, while outer cablelayer 610.o may have a right hand winding with a pitch of 0.036 inches. It is again noted that the windings and pitches employed are exemplary only. Persons skilled in the relevant arts will appreciate that other windings and other pitches are possible within the scope and spirit of the present cable and lead designs. In general, the smaller the cross-sectional area of the filaments 615 in a cable-layer 610, the tighter the windings may be.

FIG. 6E is another cross-sectional view of exemplary cable 600 configured for improved mechanical and electrical properties. FIG. 6E includes features already discussed in detailed above and the discussion will not be repeated here. Also, included in FIG. 6E are exemplary measurements of various elements of exemplary cable 600. It will be appreciated that these measurements are exemplary only and other measurements may be employed within the scope and spirit of the present cable and lead designs.

FIG. 7 A is an illustration of another embodiment of exemplary cable 700 configured for improved mechanical and electrical properties according to the present cable and lead designs. Cable 700 includes central wire 705, middle cablelayer 710.m, outer cable-layer 710.o, middle filaments 715.m of middle cable-layer 710.m, outer filaments 715.o of outer cable-layer 710.o, cable jacket 720, and filament coatings 725.

Many of the features or elements of exemplary cable 700 are the same or substantially similar to elements of exemplary cable 600 already discussed above in conjunction with FIG. 6. For example, central wire 705 corresponds to central wire 605. Middle cable-layer 710.m is substantially similar to middle cable-layer 610.m. Middle filaments 715.m are substantially similar to middle filaments 615.m, etc. A discussion of these elements, their relative orientation and structural properties and advantages has already been presented above and the discussion will not be repeated here.

32 FIG. 7C offers another cross-sectional view of exemplary

cable 700. FIG. 7C includes exemplary measurements of various elements of exemplary cable 700. Persons skilled in the relevant arts will appreciate that the measurements shown here are exemplary only. Other dimensions for various elements may be employed within the spirit and scope of the present cable and lead designs.

Persons skilled in the relevant arts will appreciate that the exact configuration shown for cable 700 is exemplary only,

10 and in implementation may vary in any number of details. More cable-layers 710 or fewer cable-layers may be employed. Similarly, the number of filaments 715 used in each cable-layer is exemplary and may vary in actual implementation. Similarly, the relative sizes of the elements are

15 exemplary only and may vary in actual implementation. FIG. SA presents a view of an exemplary cable 800 con

figured for improved mechanical and electrical properties according to the present cable and lead designs. Elements of exemplary cable 800 include central wire 805, outer cable-

20 layer 810.o, middle cable-layer 810.m, multiple outer oval filaments 815.o of outer cable-layer 810.o, and multiple middle oval filaments 815.m of middle cable-layer 810.m. These elements are the same or substantially similar as corresponding elements already described in conjunction with

25 FIGS. 6-7. For example, central wire 805 corresponds to central wires 705 and 605. Middle cable-layer 810.m is substantially similar to middle cable-layer 710.m and 610.m. Middle filaments 815.m are substantially similar to middle filaments 715.m and 615.m, etc. A discussion of these ele-

30 ments, their relative orientation and structural properties and advantages has already been presented above and the discussion will not be repeated here.

New to exemplary cable 800 is the use of two inner jackets 825 and 830. Central wire coating 825 is similar to central

35 wire coating 625 already discussed above. It helps reduce fretting fatigue between central wire 805 and middle cablelayer 810.m. Inter-middle cable-layer/outer cable-layer coating 830 is similarly configured to reduce fretting fatigue between middle cable-layer 810.m and outer cable-layer

40 810.o. In addition, exemplary cable 800 has cable jacket 820 which provides installation for the cable as a whole.

FIG. SB presents another view of exemplary cable 800. Presented in FIG. SB are exemplary measurements for various elements of exemplary cable 800 such as widths, diam-

45 eters, and pitches for the central wire 805, filaments 815 and coatings 820, 825 and 830. Persons skilled in the relevant arts will appreciate that the measurements shown are exemplary only. Other dimensions may be employed consistent with the

Notable, however, with exemplary cable 700 is that rather than central wire coating 625 (see FIG. 6) which is omitted in this configuration, filaments 715.m of middle cable-layer 710.m have individual filament coatings 730. These filament 50

coatings 730 may be comprised of any number of polymers, such as that already enumerated above.

spirit and scope of the present cable and lead designs. Persons skilled in the relevant arts will appreciate that the

exact configuration shown for cable 800 is exemplary only, and in implementation may vary in any number of details. More cable-layers 810 or fewer cable-layers may be employed. Similarly, the number of filaments 815 used in

In addition, filament coating 730 serve to reduce fretting fatigue in multiple respects. Filament coatings 730 reduce fretting fatigue between middle filaments 715.m and central wires 705. Filament coating 730 also reduce fretting fatigue due to contact pressure between middle filaments 715.m and outer filaments 715 .o. Filament coating 73 0 also reduce fretting fatigue between filaments 715.m of middle cable-layer 710.m.

FIG. 7B is another view of exemplary cable 700 configured for improved mechanical and electrical properties. FIG. 7B shows elements which are substantially the same as the elements shown in cross-sectional view in FIG. 7A. In FIG. 7B

55 each cable-layer is exemplary and may vary in actual implementation. Similarly, the relative sizes of the elements are exemplary only and may vary in actual implementation.

FIG. 9A presents a view of another exemplary cable 900 configured for improved mechanical and electrical proper-

60 ties. FIG. 9A includes a central wire 905, an outer cable-layer 910.o, a middle cable-layer 910.m, filaments 915.o of outer cable-layer 910.o, filaments 915.m of middle cable-layer 910.m, central wire coating 925, and inter-middle cable-layer/outer cable-layer coating 930.

a perspective view is offered, making clearer the windings of 65

filaments 715.o and also the overall extension of exemplary cable 700.

Unlike other embodiments shown above, such as, exemplary cables 600/800, exemplary cable 900 employs conventional filaments 915 with circular cross-sections, rather than


US 8,108,053 B2 33

the oval cross-sections discussed above for filaments 615/815 with exemplary cables 600/800.

However, exemplary cable 900 still benefits from other advantages of the present cable and lead designs. For example, exemplary cable 900 employs central wire coating 925 and inter-middle cable-layer/outer cable-layer coating 930. Central wire coating 925 reduces fretting fatigue between central wire 905 and middle cable-layer 910.m. Similarly, inter-middle cable-layer/outer cable-layer coating 930 reduces fretting fatigue between middle cable-layer 910.m andoutercable-layer910.o.As a result of coatings 925 and 930, and the consequent reduction in fretting fatigue, cable reliability is increased. In addition, due to the reduced fretting fatigue between cable-layers 910, and also between middle cable-layer 910.m and central wire 905, it is still possible to wind filaments 915 with a stronger helical winding, with the various advantageous to such windings already discussed above.

In addition, while not specifically illustrated in the figure, the metallic composition of the cable-layers may also vary with radial distance from the center, again providing the advantages discussed above. (See FIG. 10 for further discussion.) In addition, it may be seen in the figure that central wire 905 has a greater cross-sectional area than the cross-sectional area of filaments 915.m in middle cable-layer 910.m. While not illustrated in the figure, in an embodiment filaments 915.o of outer cable-layer 910.o may have a lesser cross-sectional area than filaments 915.m of middle cable-layer 910.m.

FIG. 9B is a cross-sectional view of exemplary cable 900 already discussed above. FIG. 9B includes exemplary measurements for various elements for exemplary cable 900. Persons skilled in the relevant arts will appreciate that the measurements shown are exemplary only. Others measurements may be employed consistent with the spirit and scope of the present cable and lead designs.

34 mately 20% chromium, and approximately 10% molybdenum, along with small or trace quantities of other elements), MP35N is a trademark of SPS Technologies, Inc., of Jenkintown, Pa. In an embodiment, the inner core of each filament may be comprised of high purity silver (Ag).

FIG. 10 illustrates cross-section view of several exemplary filaments 615/915 according to the present cable and lead designs. Each filament 615/915 has an exterior outer tubing 1055 which, as discussed immediately above, may be com-

10 prisedofthe alloy MP35N. Each filament also has a core 1050 running down the center and comprised of high purity silver.

As per discussion above, the cross-sectional area of a filament 615/915 may decrease with increasing distance from the center of cable 600/900. As shown in FIG. 10, central wire

15 605/905 has a larger cross-sectional area than middle filaments 615.m/915.m. Similarly, middle filaments 615.m/ 915.m have a larger cross-sectional area than outer filaments 615.o/915.o. Also consistent with the discussion above associated with FIGS. 6A-9B, filaments 615.m/815.m, 615.o/

20 815.o are illustrated as substantially oval in cross-section, while filaments 915.m and 915.o are presented as substantially circular in cross-section.

In addition, in an embodiment of the present cable and lead designs, the percentage of silver in a filament, as a percentage

25 of the total volume of the filament, may also vary with increasing distance from the center of a cable 600/900. This change in silver percentage will also be reflected in a change in the cross-sectional area of a filament which is silver, as compared with the percentage of the cross-sectional area

30 which is an alloy such as MP35N. For example, for central wires 605/905, silver core

1050.cw may be approximately 20% to 30% of the total volume and cross-sectional area of the filament, with alloy tube 1055.cw comprising the remaining 80% to 70% by vol-

35 ume and cross-sectional area. In an embodiment, a central wire 605/905 may have a silver core 1050.cw which comprises approximately 28% of the wire.

More generally it will be appreciated that in all the embodiments discussed above, that is exemplary cables 600, 700, 800 and 900 the exact configurations shown are exemplary. The number of cable-layers 910 may be greater or fewer than shown. The number of filaments 915 may be greater or fewer than shown. Configurations of jackets such as 920, 925 and 930 as well as filament coating 730 may be combined or varied in different combinations. Other elements may be added or removed consistent with the spirit and scope of the present cable and lead designs. Further, in embodiments shown above the central wire 605, 705, 805 and 905 has been illustrated as being a single filament generally oflarger cross- 45

sectional area than any of the filaments in the surrounding cable-layers 910. Persons skilled in the relevant arts will appreciate that the central filament itself may be composed either of a single filament 915 of a same cross-sectional area

For middle filaments 615.m/915.m, silver core 1050.m may be approximately 30 to 40% of the total volume and cross-

40 sectional area of the filaments, with alloy tube 1055.m comprising the remaining 70% to 60% by volume and crosssectional area. In an embodiment, a middle filament 615.m, 715.m, 815.m, 915.m may have a silver core 1050.m which comprises approximately 33% of the wire.

For outer filaments 615.o/915.o, silver core 1050.o may be approximately 40 to 60% of the total volume and crosssectional area of the filament, with alloy tube 1055.o comprising the remaining 60% to 40% by volume and crosssectional area. In an embodiment, an outer filament 615.o/

as a filament 915 in a surrounding cable-layer. In alternative embodiments, central wire 905 may actually be composed of multiple filaments 915 which may be braided, wound together, or otherwise combined or coupled to constitute a functional central wire 905.

50 915.o may have a silver core 1050.o which comprises approximately 41% of the wire.

It should be noted that any central wire coating, such as exemplary central wire coatings 625, 825, and 925 shown in various of FIGS. 6, 8, and 9 above, or filament coatings, such

Material Composition of Central Wire and Filaments 55

as exemplary coatings 730 shown in FIGS. 7, are not illustrated in FIG. 10. But, such coatings 625, 825, 925, 730, if used, would be exterior to,jacketing, and in contact with alloy tube 1055.

Central wire 605/905 and filaments 615/915 employed in exemplary cables 600/900, as well as other filaments consistent with the present cable and lead designs, may be comprised of a variety of conducting materials, including for example and without limitation such metals as silver, copper, nickel, chromium, aluminum, iron, molybdenum, tin, plati- 60

num, gold, cobalt, tungsten, etc., and alloys of such metals. In an embodiment, central wire 605/905 and filaments

615/915 are constructed as drawn filled tube (DFT) wires having a drawn outer tube filled with an inner core material. In an embodiment, the outer tube of each filament may be com- 65

prised of the alloy MP35N® (an alloy composed of approximately 35% cobalt, approximately 35% nickel, approxi-

It should be further noted that elements of FIG. 10 are intended to illustrate relative dimensions, such as for example the relative percentages of silver compared with alloy in a central wire, a middle filament, and an outer filament, without necessarily being drawn exactly to scale. It will also be understand by persons skilled in the relevant arts that the relative percentages of core metal 1050 compared with tube metal 1055 may vary from that described above. In particular, in embodiments with only one layer of cable-layer 910 sur-rounding central wire 905, or with three or more layers of


US 8,108,053 B2 35

cable-layers 910 surrounding central wire 905, the percentages of silver in successive cable-layer(s) may vary from that described above.

In an embodiment, the percentage of silver in the core 1050 as compared with the percentage of alloy in the filament tube 1055 will progressively increase in filaments 615/915 working outwards from the central wire 605/905, through one or more middle cable-layers 610.m/910.m, towards an outermost cable-layer 610.o/910.o.

It should also be noted that the choice of silver for filament 10

core 1050 and MP35N for tube 1055 is exemplary only. In alternative embodiments, other metals and/or alloys may be employed for core 1050, and other metals and/or alloys may be employed for tube 1055. Depending on the choice of material for core 1050 and tube 1055, the percentage of core 15 material1050 may decrease (rather than increase) working outwards from the central wire 605/905 towards an outermost cable-layer 610/910.

As already described above, the choice of both materials for filament core material 1050 and filament tube 1055, as well as the relative percentages allocated between core 1050 20

and tube 1055, is generally selected such that the strength of the materials decreases from the center wire 605/905 to one or more middle layers 610.m/910.m to the outer layer 610.o/ 910.o, such that cable 600/900 as a whole will offer higher tensile strength but less flex/bending stiffness. Materials and 25

relative percentages will also be chosen with a view towards reducing DC resistance and optimizing MRI compatibility, as already described above.

Alternative Embodiments 30

36 embodiments, for example in rope cable 1100. For example, strand filaments 1115 could be configured to have oval crosssections, and the oval cross-sections oriented to maximize a contact area between strand filaments 1115 and central filament 1125, or to maximize a contact area between strand filaments 1115 and surrounding strand filaments of a second strand layer (not illustrated), with the advantages already described above.

Similarly, various types of polymer jackets could be employed around strand filaments 1115, ropes 1120, rope core 1105, rope layer(s) 1110, and/or central strand filament 1125 and/or elements thereof to reduce fretting fatigue between these elements. Similarly, the composition, for example (ratios of metals employed in construction) of strand filaments 1115 and/or central strand filament 1125 may be varied depending on radial distance from a central locus or based on other geometric or structural considerations, with the advantages already described above. Similarly, the crosssectional area of strand filaments 1115, central strand filament 1125, and strands 1120 may be varied with radial distance from a central locus or based on other geometric or structural considerations, with the advantages already described above.

More generally, persons skilled in the relevant arts will recognize that the elements disclosed herein may be combined in a variety of manners, in conducting cables of various configurations, to achieve some or all of the advantages described herein.

CONCLUSION

It is to be appreciated that the Detailed Description section, and not the Summary and Abstract sections, is intended to be used to interpret the claims. The Summary and Abstract sections may set forth one or more but not all exemplary embodi-

Described above have been a number of exemplary embodiments 600/900 of cable conductors configured for improved mechanical and electrical performance in implantable biomedical leads. Referring again to FIGS. 6-10, such cables have comprised a central wire 605/905, cable layers 610/910, filaments 615/915 of the cable layers 610/910, and various coatings and jackets 620, 625, 720, 730, 820, 825, 920, 925, 930. Other elements, not shown or discussed, may

35 ments of the present cable and lead designs as contemplated by the inventor(s), and thus, are not intended to limit the present apparatus and method and the appended claims in any way.

be included as well, consistent with the present cable and lead designs. 40

Persons skilled in the relevant arts will appreciate that conducting cables may be designed and configured with various elements, such as wires 605/905, filaments 615/915, and other elements combined in a manner different than that illustrated and described above in FIGS. 6-10. FIG. 11, for 45

example, illustrates an exemplary cable 1100 which, using terminology sometimes employed in the art, may be known as a rope cable 1100.

Rope cable 1100 may employ a plurality of strands 1120, where each strand may be comprised of multiple strand fila- 50

ments 1115 which are wrapped or twisted together in a spiral or helical fashion, or otherwise coupled to each other. Strand filaments 1115 may, for example, be wrapped in spiral or helical fashion around a central strand filament 1125. In turn, and as illustrated in FIG. 11, the plurality of strands 1120 may

55 be wrapped in spiral or helical fashion around a rope core 1105 to form a rope layer 1110. While not shown in the figure, additional rope layers 1110 may be employed, each layer 1110 surrounding a layer 1110 interior to itself. The plurality of strands 1120 may also be bonded, coupled, or joined in some other fashion. Rope core 1105 may be a single, unitary 60

wire, or may itself be comprised of multiple filaments conjoined or coupled in various manners.

While not shown in rope cable 1100 of FIG. 11, persons skilled in the relevant arts will recognize that the elements, systems, and methods disclosed elsewhere herein, in con- 65

junction with other embodiments of the present cable and lead designs, may be advantageously employed in other

Moreover, while various embodiments of the present cable and lead designs have been described above, it should be understood that they have been presented by way of example, and not limitation. It will be apparent to persons skilled in the relevant art( s) that various changes in form and detail can be made therein without departing from the spirit and scope of the present cable and lead designs. Thus, the present cable and lead designs should not be limited by any of the above described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

In addition, it should be understood that the figures, which highlight the functionality and advantages of the present cable and lead designs, are presented for example purposes only. The architecture of the present cable and lead designs is sufficiently flexible and configurable, such that it may be constructed and utilized in ways other than that shown in the accompanying figures. Moreover, the steps, processes, methods, and/or construction techniques indicated in the exem-plary system( s) and method( s) described above may in some cases be performed in a different order, or by combining elements in a different marmer, than the order or manner described, and some steps may be added, modified, or removed, without departing from the spirit and scope of the present cable and lead designs.

Further, the purpose of the foregoing Abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the


US 8,108,053 B2 37

application. The Abstract is not intended to be limiting as to the scope of the present cable and lead designs in any way.

What is claimed is: 1. A cable comprising: a conductive central core; and at least one conductive cable-layer concentric with the

central core and surrounding at least one of the conductive central core and a conductive cable-layer interior to itself;

wherein: 10

each at least one conductive cable-layer is comprised of a plurality of conductive filaments, said filaments configured to provide an elongated contact area between the at least one conductive cable-layer and either the conductive central core or a second conductive cable-layer 15 immediately interior to the at least one conductive cablelayer.

2. The cable of claim 1, wherein a conductive filament of the at least one conductive cable-layer has a substantially oval cross section.

3. The cable of claim 2, wherein: the elongated contact area of the substantially oval cross

section conductive filament is substantially parallel to a longer cross-sectional axis of the filament; and

20

the elongated contact area of the substantially oval cross section conductive filament is oriented such that the 25

elongated contact area makes contact with at least one of the conductive central core or the second conductive cable-layer;

wherein the substantially oval cross section conductive filament is configured to maximize a contact area 30

between the at least one conductive cable-layer and at least one of the conductive central core or the second conductive cable-layer.

4. The cable of claim 1, wherein the cross sectional area of a filament of the plurality of conductive filaments progres- 35 sively decreases with an increasing radial distance from the conductive central core, wherein:

the conductive central core has a cross sectional area that is greater than a cross sectional area of a filament in the cable-layers; and

each filament of a first cable-layer of the at least one con- 40

ductive cable-layers has a cross-sectional area that is greater than a cross sectional area of a filament of a cable-layer exterior to the first cable-layer.

5. The cable of claim 1, wherein the material composition of a filament progressively changes with an increasing radial 45

distance from the conductive central core, the material composition determining a material strength of the filament, wherein:

the conductive central core has a material strength that is greater than a material strength of each filament in the 50

cable-layers; and each filament of a first cable-layer of the one or more

cable-layers has a material strength that is greater than a material strength of a filament of a cable-layer exterior to the first cable-layer.

6. The cable of claim 5, wherein: the conductive central core and each filament of the at least

one conductive cable-layer comprises an inner silver core and an outer alloy;

55

the conductive central core has a lower percentage silver content of its inner silver core than a percentage silver 60

content of the inner cores of the filaments in the at least one conductive cable-layer; and

each filament of a first conductive cable-layerofthe at least one conductive cable-layer has a lower percentage silver content of its inner silver core than percentage silver 65

content of an inner core of a filament of a conductive cable-layer exterior to the first conductive cable-layer.

38 7. The cable of claim 6, wherein: the conductive central core has a silver content in a range of

approximately 20% to 30%; each conductive filament of a first conductive cable-layer

immediately surrounding the conductive central core has a silver content in a range of approximately 30% to 40%; and

each conductive filament of a second conductive cablelayer immediately surrounding the first conductive cable-layer has a silver content in a range of approximately 40% to 60%.

8. The cable of claim 1, further comprising a non-conductive coating between at least one of:

the conductive central core and a conductive cable-layer immediately surrounding the conductive central core; or

a first conductive cable-layer of the at least one conductive cable-layer and an immediately adjacent second cablelayer of the at least one conductive cable-layer;

wherein: the non-conductive coating is configured to reduce a fret

ting fatigue at the elongated contact area while mediating and maintaining the elongated contact area.

9. The cable of claim 1, further comprising a non-conductive coating jacketing each filament of a least one cable-layer of the at least one conductive cable-layer, wherein the nonconductive coating is configured to minimize at least one of:

a fretting at the area of contact between the cable-layer and either the conductive central core or a cable-layer immediately adjacent to itself; and

a fretting fatigue at the area of contact between the plurality of filaments of the cable-layer.

10. A lead comprising: an extended exterior insulating body having a lumen; and a cable disposed within said lumen, said cable comprising: a conductive central core; and at least one conductive cable-layer concentric with the


wherein: each at least one conductive cable-layer is comprised of a

plurality of conductive filaments, said filaments configured to provide an elongated contact area between the at least one conductive cable-layer and either the conductive central core or a second conductive cable-layer immediately interior to the at least one conductive cablelayer.

11. The lead of claim 10, wherein: a conductive filament of the at least one conductive cable

layer has a substantially oval cross section; and the elongated contact area of the substantially oval cross

section conductive filament is substantially parallel to a longer cross-sectional axis of the filament; and

the elongated contact area of the substantially oval cross section conductive filament is oriented such that the elongated contact area makes contact with at least one of the conductive central core or the second conductive cable-layer;

wherein the substantially oval cross section conductive filament is configured to maximize a contact area between the at least one conductive cable-layer and at least one of the conductive central core or the second conductive cable-layer.

12. Theleadofclaim 10, wherein the cross sectional area of a filament progressively decreases with an increasing radial distance from the conductive central core, wherein:

the conductive central core has a cross sectional area which is greater than a cross-sectional area of each filament in the cable-layers; and


US 8,108,053 B2 39

each filament of a first cable-layer of the at least one conductive cable-layer has a cross-sectional area which is greater than a cross-sectional area of a filament of a cable-layer exterior to the first cable-layer.

13. The lead of claim 10, wherein the material composition of a filament progressively changes with an increasing radial distance from the conductive central core, the material composition determining a material strength of the filament, wherein:

the conductive central core has a material strength which is 10

greater than a material strength of each filament in the cable-layers; and

each filament of a first cable-layer of the one or more cable-layers has a material strength which is greater than a material strength of a filament of a cable-layer exterior 15

to the first cable-layer. 14. The lead of claim 10, further comprising a non-con

ductive coating between at least one of: the conductive central core and the cable-layer immedi

ately surrounding the conductive central core; or 20

40 wherein: the cross sectional area of a filament of the plurality of

conductive filaments progressively decreases with an increasing radial distance from the conductive central core, wherein:

the conductive central core has a cross sectional area which is greater than a cross-sectional area of a filament in the cable-layers; and

each filament of a first cable-layer of the at least one conductive cable-layers has a cross-sectional area which is greater than a cross-sectional area of a filament of a cable-layer exterior to the first cable-layer;

and; the material composition of a filament progressively

changes with an increasing radial distance from the conductive central core, the material composition determining a material strength of the filament, wherein:

the conductive central core has a material strength which is greater than a material strength of a filament in the cable-layers; and

each filament of a first cable-layer of the one or more cable-layers has a material strength which is greater than a material strength of a filament of a cable-layer exterior to the first cable-layer.

a first cable-layer and an immediately adjacent second cable-layer of the at least one conductive cable-layer;

wherein: the non-conductive coating is configured to minimize a

fretting fatigue.

18. The cable of claim 17, wherein a conductive filament of the at least one conductive cable-layer has a substantially oval

25 cross section, wherein:

15. The lead of claim 10, further comprising a non-conductive coating jacketing each filament of a least one cablelayer of the at least one conductive cable-layer, wherein the non-conductive coating is configured to minimize at least one of:

a fretting fatigue at the area of contact between the cablelayer and either the conductive central core or a cablelayer immediately adjacent to itself; and

a fretting fatigue at the area of contact between the plurality of filaments of the cable-layer.

16. An implantable system for delivery of cardiac therapy comprising:

an implantable cardiac therapy device (ICTD); and

30

35

a lead configured to be connected at a proximal end to said ICTD and configured to be attached at a distal end to a

40 tissue of a patient; wherein said lead comprises: an extended exterior insulating body having a lumen; and a cable situated within said lumen, said cable comprising: a conductive central core; and at least one conductive cable-layer concentric with the 45


wherein: each at least one conductive cable-layer is comprised of a 50

plurality of conductive filaments, said filaments configured to provide an elongated contact area between the at least one conductive cable-layer and either the conductive central core or a second conductive cable-layer immediately interior to the at least one conductive cable- 55 layer.

17. A cable, comprising: a conductive central core; at least one conductive cable-layer concentric with the

central core and surrounding at least one of the conductive central core and a conductive cable-layer interior to 60

itself; and a plurality of conductive filaments of the at least one con

ductive cable-layer;

an elongated surface contact area of the substantially oval cross section conductive filament is oriented such that the surface elongated contact area makes contact pressure with at least one of the conductive central core or the second conductive cable-layer.

19. The cable of claim 17, wherein: the conductive central core and each filament of the at least

one conductive cable-layer comprises an inner silver core and an outer alloy surrounding the inner silver core;

the conductive central core has a percentage silver content of its inner silver core which is less than a percentage silver content of a filament in the at least one conductive cable-layer; and

each filament of a first conductive cable-layer of the at least one conductive cable-layer has a percentage silver content of its inner silver core which is less than a percentage silver content of a filament of a conductive cablelayer exterior to the first conductive cable-layer.

20. The cable of claim 17, further comprising a non-conductive coating between at least one of:

the conductive central core and a conductive cable-layer immediately surrounding the conductive central core;

a first conductive cable-layer of the at least one conductive cable-layer and an immediately adjacent second cablelayer of the at least one conductive cable-layer;

wherein: the non-conductive coating is configured to reduce a fret

ting fatigue at the area of contact while mediating and maintaining the elongated contact area.

21. The cable of claim 17, further comprising a non-conductive coating jacketing each filament of a least one cablelayer of the at least one conductive cable-layer, wherein the non-conductive coating is configured to minimize at least one of:

a fretting fatigue between the cable-layer and either the conductive central core or a cable-layer immediately adjacent to itself; and

a fretting fatigue between the plurality of filaments of the cable-layer.

* * * * *


111111 1111111111111111111111111111111111111111111111111111111111111

c12) United States Patent Calvarese

(54) CUSTOMIZABLE MECHANICALLY PROGRAMMABLE RFID TAGS

(75) Inventor: Russell Calvarese, Stony Brook, NY (US)

(73) Assignee: Symbol Technologies, Inc., Holtsville, NY (US)


(21) Appl. No.: 11/847,974

(22) Filed: Aug. 30, 2007


US 2009/0058599 Al Mar. 5, 2009

(51) Int. Cl. GOSB 13114 (2006.01)

(52) U.S. Cl. ................... 340/572.1; 340/10.1; 340/10.5 (58) Field of Classification Search ................. 340/572,

(56)

340/10 See application file for complete search history.

References Cited


6,734,797 B2 6,805,291 B2 * 6,840,444 B2 * 6,869,020 B2 * 6,869,021 B2 * 7,151,455 B2

5/2004 Shanks et a!. 10/2004 Chhatpar et al ............. 235/383

112005 Pierce eta!. ................ 235/383 3/2005 Foth eta!. ................... 235/492 3/2005 Foth eta!. ................... 235/492

12/2006 Lindsay eta!.

11 Oa 112

US007876222B2

(10) Patent No.: US 7,876,222 B2 Jan.25,2011 (45) Date of Patent:

7,168,626 B2 * 7,170,415 B2 7,212,127 B2 7,304,578 B1 *

2004/0074963 A1 * 2004/0075348 A1 * 2005/0092839 A1 * 2005/0104790 A1 * 2006/0152364 A1 * 2007/0069029 A1 * 2007/0096876 A1

112007 Lerch eta!. ................. 235/492 112007 Forster 5/2007 Jacober eta!.

12/2007 Sayers eta!. ............. 340/572.3 4/2004 Pierce et al. . ............... 235/383 4/2004 Obrea eta!. ................ 307/125 5/2005 Oram .................... 235/462.13 5/2005 Duron ........................ 343/745 7/2006 Walton .................... 340/568.1 3/2007 Bauchot eta!. ........ 235/462.45 5/2007 Bridgelall et al.

OTHER PUBLICATIONS

Swedberg, Claire, "Mikoh Develops Reusable Container with RFID Security Seal", The World's RFID Authority: RFID Journal, Feb. 15, 2007, 2 pages.

* cited by examiner

Primary Examiner-Travis R Runnings

(57) ABSTRACT

A system and method to track a status an item, or steps in a process, via one or more mechanical modifications to an RFID tag. In one embodiment, a plurality oftearable strips are attached to the tag, each strip having an electrical conductor. Each tearable strip may receive a visual or tactile indicia, such as text, a color code, a graphic symbol, or a tactile indicator (such as Braille) to assign a meaning to the strip, where the meaning is associated with the status or condition of the item, or the stage, step, or status or the process. By tearing some strips or all strips, a desired bit pattern may be programmed into a register of the RFID tag. The bit pattern may reflect the status or condition of the item, or the stage, step, or status of a process.


/100

I

J 112& READER ~ ;i5 T 102b

104a) 112~ 102a

112~ 112~ 102c

fi5112 102g

11 Ob 1 02f

I

READER J ~ 112~ 102d

104b) 102e

120


U.S. Patent Jan.25,2011 Sheet 1 of 17 US 7,87 6,222 B2

/100

110a lr--R-EA_D_E_R___, J ~ 112 112~-

~ ~ 102b 104a)

102a 112~ 112~ 112~ 102c

T ~ 112 102g ~

11 Db '"I_R_E_A_D-ER-..., J ~

104b)

102f ~ 112~ 102d

102e 120

FIG. 1

104

ANTENNA 202 220 ~

----------------------------------~------------~ ' ,--------, 210:

~- •••••••• 0 ••••••• :

MODULATOR! ~-!----. : 222 : : 218 ENCODER 208 ; BASEBAND : ) : NETWORK ; )

....___ ___ __. 214 : PROCESSOR :~ INTERFACE j....C.. 212 : 216 : . . . .

I o ' •

: ~- ................ _j L ................. j ' ' ' ' ----------------------------------------------•

FIG. 2



102

~

302

IC DIE

MEMORY r----.-- 308

IDENTIFICATION -......____.. 318 NUMBER

-----320

CONTROL LOGIC r---- 310

r---- 326 -----322 r--..-324

CHARGE DEMODULATOR MODULATOR

PUMP 314

~ l316 312

r---- 328 l306

ANTENNA -----304

FIG. 3



402

~ 412 412

,------- - - ,------- ,-- -

302

? 414~

414--IC DIE

MEMORY ~308

STRIP STATE IDENTIFICATION I-- ...___... 318

REGISTER NUMBER

4{o ~320

STRIPSTATE 7 CONTROL LOGIC ~310

DETERMINATION

("' 418 416 ~326 r------- 3 22 ~324


PUMP 314

("' l316 312

328 ..._.-l306

304 ANTENNA I

FIG. 4



402

~ 412 412

- - ,--- ,--- - ,---

414S ' ' [',' ' ' ' ' ' ' ' ' ' ' P~414L ' ' ' ' : ' ' ' ' ' ' 302 ' ' ' /

? 414L~ ~414L

414A ____....- . . . . 414 B ____...--- ~414L

. . . . . IC DIE

MEMORY ~308

STRIP STATE IDENTIFICATION ~ ...._____ 318 ... REGISTER NUMBER . . .

1.11.11.1 4{o ~320

STRIPSTATE v CONTROL LOGIC ~310

DETERMINATION

(" 418 416 r----- 326 ~322 ~324


PUMP 314

(" l316 312

328 ..__..... l306

304 ANTENNA I

FIG. 5



402

~ 412R 412R

414<(_ .---- .---- - - .---- -

" r/_\ - I"" I"" - - I"" I"" ' ' ' ' 1-' ' ~414L ' ' ' ' ' I I '

502 I ' 502 I ' ' '

\...__ ' ' LV 302 ~ - - - - -

? h,j14L ~414L

: IC DIE :

414X rJ14B

MEMORY ..--......__... 308 v414A STRIP STATE IDENTIFICATION

1-- ------- 318 REGISTER NUMBER

'- II II 4ro ~320

STRIP STATE CONTROL LOGIC ..--......__... 310

DETERMINATION ! ~ 418 r------ 326 416 r-----.- 3 22 ..--......__... 324


PUMP 314

~ l316 312

~328 ( 306

ANTENNA 304

FIG. 6



402

~ 412R 412R

~ ...___!_ ~ ____]__ ,--!. ____.2._ ~ _]_ 414C.___ ,-,, -· - - - I"'"" I"'"" I"'"" --

i i ~414L

502 502

~ ·-' v 1 302 - - - - - - -

? 414L~ - ~414L

STRIP STATE DETERMINATION

STRIP STATE REGISTER [JJ[JJ[JJ[JJ[JJ[JJ[J]Cfl 0 1 2 3 4 5 6 7

~ (

702 420 416 MEMORY r------ 308

418'-- IDENTIFICATION ~ r------ 318

NUMBER

~320 CONTROL LOGIC ~310

r------ 326 ~322 r------ 324


PUMP 314

~ l316 IC DIE 312

,........_____ 328 (306

I ANTENNA 304

FIG. 7



_j412S1

0 402

~ 412R

0 ~ ~ ~ ,--±.. ~ 6 7 .. ,----- ,-----

~ I'"'" I'"'" - - I'"'" - ~ 502 r--~414L

502 502

4 ~ ~

12S2~1· .. "l - - - - - - .1 302

? 4148..........---

STRIP STATE DETERMINA.I!ON. __ --- --STRIP STATE REGISTER ft OJ OJ OJ-~ OJ OJ OJ> I - t- --2- ~ - -5- -6 ---7

~ ( 802 702

420 416 MEMORY ----.....- 3 08

418'- IDENTIFICATION I-- ------ 318

NUMBER

~320 CONTROL LOGIC ----.....- 31 0

----.....- 326 r----- 322 ----.....- 3 2 4


PUMP 314

IC DIE ~

1316 312

..-......_., 328 1306

I ANTENNA 304

FIG. 8



402

~ 412

0 ...J_ _L 3 .1--- ~ ~ __]__

I"'"" ~ I"'"" - - =: ~414L

502 502

4 ~ 1/

.J. 302 12S2\_r ...

1 - -

r ·· ·1 - ·- -?

414S~

STRIP STATE DETERMINATION ------ -STRIP STATE REGISTER /~~gJ-~-~~EJ-~ I

~ I

802 702 420 416 MEMORY r------ 308

418"'-- IDENTIFICATION I-- r------ 318

NUMBER

-~320 CONTROL LOGIC ~310

........___., 326 ........___., 322 ........___., 324


PUMP 314

~ l316 IC DIE 312

~328 l306

I ANTENNA 304

FIG. 9



402a

~ _J412B

0 412R

0 ~ _2_ ,---L _i_ _2__ ____L ___]_ .. - - ~ ~ - ~ F

~414L -

414L~ 502

4128~1" •• "] - - - - - - I.Li----1 302

? 414S~

II 1004 STRIP STATE DETERMINATION

- f-- VALUE CONTROL

lJ- -

STRIP STATE REGISTER ft~ ~ 9 -~t ~-=: ~ ( 8oi 702

416 420 MEMORY -..._., 308

IDENTIFICATION r-- ---...... 318 NUMBER

418"-f----320

I CONTROL LOGIC 310

1066" I

~326 ~322 ~324

I CHARGE I DEM0~~4LATOR I ~MODULATOR I

PUMP

IC DIE ~I

312 l316

-.____... 328 1306

I ANTENNA 304

FIG. 10



402

~

412R

1104 2 3 4 5 6

306

302

FIG. 11



402

1212 ....__........-~

1210 ....__........-

FIG. 12A

1206

FIG. 128


U.S. Patent

412P

1104

Jan.25,2011 Sheet 12 of 17

412P 412P 412P

(]) CJ) ......

r::: ..c co 0

(.) 0 r::: co ::::l

co _J !.....

!..... (])

0 ·;:: a. r::: ~ E 0 co ::::l ~ (/) co

1302~ Return to any ATM in park for refund of

unused items

FIG. 13

412P

US 7,87 6,222 B2

402b

r

(]) u 0:: >-

.:::£. (/)



412

~ 402

~

~ - r-- I-- C> - (.)

0 c -

1104

en E ¢:! .:t= +=' Ct:l 0 .c .0 E en

~ Q) "'0 Ct:l c c Ct:l (.)

Ct:l 0 Q) ~

.._ ~ .c

.._ 0 0 (.) .c N

0 ..... +-' (") Q)

.0 Q) Q)

+-' > "'0 ::::l en 0 ...__.... ra.> c C" ::::l E .._ .._

0 >. 0 ~ Q) (Q 0 I- <( 0:::

Alarm will sound if 1302 --------- process is performed in

incorrect order

General Auto Company

FIG. 14



N_/1 •• ~;g • ....--....--""'"

....--

N_/1 0~3 ....-- ....--

""'" ....--

N_/1 B~~ ....-- ....--

""'" ....--

N_/1 ~~ ....-- ....--

""'" ....--

N_/1 ·o)a 'an1s 'uaaJ8 'pa~~ ;g ll) "'f""'"

....-- ....-- . ""'"

....--C) -LL

N_/1 ~~3 ....-- ....--

""'" ....--

N_/1 V9VZHV'~;i\ ....-- ....--

""'" ....--

N_/1 LL9Z~2\ ....-- ....--

""'" ....--

N_/1 ~001q aJOS~ 3

....-- ....--

""'" ....--



412

1604

1104

1602

Sheet 15 of 17

1606,-f-'

FIG. 16

US 7,87 6,222 B2

• 1104--r-e.



Dotted lines indicate optional steps

1750

r - - - - - S- -----~ 1 Render unchangeable 1 I values associated with~ - -: bits of RFID tag :

Start 1702

Assign RFID tag to item or process .../'""'

-----1 ~------

I I

Associate strips of RFID tag with

1705 1755

r------~-----1 Modify default values :

- .,1 associated with bits of 1 I I 1 RFID tag 1 ._ ___________ _

r----- - respective process steps or item -1

I

r- --- ---- j_-- - - -

conditions/statuses

---1

that I I I I

17~0 r----I I 1 Physic

I I

- - - - - j_ - - - - - - - 1

1 Configure RFID tag/strips so I upon performance of step or : determination of appropriate 1 status, respective strip of RF : will be automatically mechan

ID tag I

ically :

1 associ I . t 1 1tem s

I I

ally label strips to indicate I

ation of process steps or : atuses with respective strips 1

1 modified I 1715 I I

I I

~------)-i _____ _ ___ I

\ 1..---- ------:---)---_I

1760 :

-+

Upon performance of step or determination of appropriate status, mechanically modify respective strip of RFID tag

17\20

Read RFID tag to determine bit status of register which monitors strips

Determine status of process or item based on bit pattern

FIG. 17

: 1765 I

f-4- ______ ..,j


U.S. Patent

Dotted lines indicate optional steps

1812

1822

Jan.25,2011 Sheet 17 of 17 US 7,87 6,222 B2

1802

Accept via an RF link of the RFI D tag 1805 an identification of bits of the register

Accept via the RF link an indication of ,--------1 whether the bits are to be given a 1810

different default value, or are to be fixed at a specific value

1814~ .. --- ---------I I

J, :No I

/' ', 1--../'1817 ..- , I

..- ..- Detect mechanical modification' ' , , 1

' , of control strip? ..- ..-~ --- ----'C ' ..- )

- - -------- 1816 ~--

1818~Yes I

Modify Fix

Modify default value of indicated bit Fix value of bit so it does not change when associated strip is mechanically modified

1830 1835

FIG. 18


US 7,876,222 B2 1

CUSTOMIZABLE MECHANICALLY PROGRAMMABLE RFID TAGS

BACKGROUND

The invention relates in general to the arrangement and use of radio frequency identification (RFID) tags. In particular, the inventions relate to programming a value on an RFID tag using mechanically alterable elements of the tag.

2 made to avoid obscuring the purpose of the section. Such simplifications or omissions are not intended to limit the scope of the claimed inventions.

The invention described in this patent document relate in general to mechanically modifiable RFID tags, where such mechanical modifications are used to change an internally stored or internally represented data state of the tag. In an embodiment, an RFID tag may have attached to it a plurality of strips, which may be strips of paper, and which can be tom.

Radio frequency identification (RFID) tags are electronic devices that may be affixed to items whose presence is to be detected and/or monitored. RFID tags are classified based on standards defined by national and international standards bodies (e.g., EPCGlobal and ISO). Standard tag classes include Class 0, Class 1, and Class 1 Generation 2 (referred to herein as "Gen 2"). The presence of an RFID tag, and therefore the presence of the item to which the tag is affixed, may

10 A bit pattern stored in a register of the RFID tag is modified by tearing the strips. Each strip can be readily impressed with some identifier, which may be print or tactile, and which indicates to a human user a meaning of the strip.

The invention can be implemented in numerous ways, 15 including methods, systems, devices, and computer readable

medium. Several embodiments of the invention are described below, but they are not the only ways to practice the invention described herein. be checked and monitored wirelessly by an "RFID reader",

also known as a "reader-interrogator", "interrogator", or simply "reader." Readers typically have one or more antennas for 20

transmitting radio frequency signals to RFID tags and receiving responses from them. An RFID tag within range of a reader-transmitted signal responds with a signal including a unique identifier.

With the maturation ofRFID technology, efficient commu- 25

nication between tags and readers has become a key enabler in supply chain management, especially in manufacturing, shipping, and retail industries, as well as in building security installations, healthcare facilities, libraries, airports, warehouses etc. Many processes, as well as the status of many 30

items, may be readily monitored via RFID tags RFID tags have been developed where, by means of

mechanical alterations to a tag (such as, for example, by severing or completing an external circuit path associated with the tag), it is possible to modify an internal data state of 35

the tag. In this way, an RFID tag may be used to report on a mechanically changed state or other condition of items with which a tag is associated. For example, an RFID tag attached to a container of medicine may be used to monitor, and to report on, whether the container has been tampered with, or 40

whether the cap has been removed. Similarly, RFID tags may


The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate the invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention.

In the drawings, like reference numbers indicate identical or functionally similar elements.

Additionally, references numbers which are the same, but vary by virtue of an appended letter of the alphabet (for example, 412, 412R, 412P, 412S) or an appended letter and number (for example, 412, 412S1, 412S2) indicate elements which may be substantially the same or similar, but represent variations or modifications of the basic element. In some cases, the reference number without the appended letter or without the appended letter and number (for example, 412) may indicate a generic form of the element, while reference numbers with an appended letter or an appended letter and number (for example, 412S, 412S1, 412S2, 412P) may indicate a more particular or modified form of the element.

be used to report on markings made on a written sheet, provided the conductivity of the sheet is altered in the process of marking the sheet, and provided a circuit path associated with the RFID tag is thereby modified as well.

Additionally, the leftmost digit(s) of a reference number identifies the drawing in which the reference number first appears. For example, an element labeled 412 typically indi-

45 cates that the element first appeared in FIG. 4. In general then, there have been uses of RFID tags where

mechanical, "off-chip", modifications to a circuit path have been employed to modify a data state of a tag, and so modify the data reported by the tag. Generally, however, custom RFID tags and custom off-chip or custom off-tag mechanisms so have been employed for these purposes. There has been no general-purpose, off-the-shelf, mechanically-programmable RFID tag, usable in a wide variety of contexts and applications as new needs arise, which can be easily used to generically monitor items or processes as changes occur.

What is needed, then, is an RFID tag which can be easily mechanically modified to indicate and report changes in data states, and which can further be easily applied to and integrated into diverse contexts for item/process monitoring and reporting purposes.

SUMMARY

FIG. 1 shows an environment where RFID readers communicate with an exemplary population of RFID tags.

FIG. 2 shows a block diagram of receiver and transmitter portions of an RFID reader.

FIG. 3 shows a block diagram of an exemplary radio frequency identification (RFID) tag.

FIG. 4 shows a block diagram of an exemplary mechanically programmable RFID tag according to the present sys-

55 tern and method. FIG. 5 shows another view of a block diagram of an exem

plary mechanically progrmable RFID tag according to the present system and method.

FIG. 6 shows another view of a block diagram of an exem-60 plary mechanically progrmable RFID tag according to the

present system and method.

This section is for the purpose of summarizing some aspects of the inventions described more fully in other sec- 65

tions of this patent document. It briefly introduces some preferred embodiments. Simplifications or omissions may be

FIG. 7 shows another view of a block diagram of an exemplary mechanically progrmable RFID tag according to the present system and method.

FIG. 8 shows another view of a block diagram of an exemplary mechanically progrmable RFID tag according to the present system and method.


US 7,876,222 B2 3

FIG. 9 shows another view of a block diagram of an exemplary mechanically programmable RFID tag according to the present system and method.

FIG. 10 shows another view of a block diagram of an

4 3. Exemplary Customizable Mechanically Programmable RFID Tags

4. Mechanical Modification of Exemplary RFID Tags

exemplary mechanically progrannnable RFID tag according 5 5. Determination of Strip States of Exemplary RFID Tags to the present system and method.

FIG. 11 shows an exemplary mechanically programmable RFID tag according to the present system and method.

FIG. 12A shows another view of an exemplary mechanically progrannnable RFID tag according to the present system and method.

FIG. 12B shows another view of an exemplary mechanically progrannnable RFID tag according to the present system and method.

6. Changing Values Associated With Strips of Exemplary RFID Tags

7. Further Exemplary RFID Tags and Features Thereof 10

8. Applications of Exemplary Customizable, Mechanically Programmable RFID Tags

9. Methods Associated With Customizable, Mechanically Programmable RFID Tags

FIG. 13 shows another view of an exemplary mechanically 15 10. Alternative Embodiments programmable RFID tag according to the present system and method.

FIG. 14 shows another view of an exemplary mechanically programmable RFID tag according to the present system and

11. Conclusion

1. EXEMPLARY OPERATING ENVIRONMENT

method. 20 Before describing embodiments of the invention in detail,

it is helpful to describe an example RFID communications environment in which the inventions may be implemented. FIG. 1 illustrates an environment 100 where RFID tag readers

FIG. 15 shows a view of exemplary mechanically alterable elements of an exemplary mechanically programmable RFID tag according to the present system and method.

FIG. 16 shows another view of exemplary mechanically alterable elements of an exemplary mechanically programmable RFID tag according to the present system and method.

25 104 (readers 104a and 104b shown in FIG. 1) communicate with an exemplary population 120 of RFID tags 102. As shown in FIG. 1, the population 120 of tags includes seven tags 1 02a-1 02g. A population 120 may include any number of FIG. 17 is a flow chart of an exemplary method for moni

toring an item status or process steps with an exemplary mechanically programmable RFID tag according to the

30 present system and method.

tags 102. Environment 100 includes any number of one or more

readers 104. For example, environment 100 includes a first reader 104a and a second reader 104b. Readers 104a and/or 104b may be requested by an external application to address the population of tags 120. Alternatively, reader 104a and/or

FIG. 18 is a flow chart of an exemplary method for using a radio frequency (RF) signal to modifY the values or the default values of bits associated with exemplary mechanically modifiable elements of an exemplary mechanically programmable RFID tag according to the present system and method.


In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the

35 reader 104b may have internal logic that initiates communication, or may have a trigger mechanism that an operator of a reader 104 uses to initiate communication. Readers 104a and 104b may also communicate with each other in a reader network (see FIG. 2).

40 As shown in FIG. 1, reader 104a "reads" tags 120 by transmitting an interrogation signal110a to the population of tags 120. Interrogation signals may have signal carrier frequencies or may comprise a plurality of signals transmitted in a frequency hopping arrangement. Readers 104a and 104b

45 typically operate in one or more of the frequency bands allotted for this type of RF communication. For example, the Federal Communication Commission (FCC) defined frequency bands of 902-928 MHz and 2400-2483.5 MHz for

art that the invention, including structures, systems, and methods, may be practiced without these specific details. The description and representation herein are the common means used by those experienced or skilled in the art to most effectively convey the substance of their work to others skilled in the art. In other instances, well-known methods, procedures, components, and circuitry have not been described in detail to 50 avoid unnecessarily obscuring aspects of the invention.

certain RFID applications. Tag population 120 may include tags 102 of various types,

such as, for example, various classes of tags as enumerated above. Thus, in response to interrogation signals, the various tags 102 may transmit one or more response signals 112 to an interrogating reader 104. Some of the tags, for example, may

References in the specification to "one embodiment," "an embodiment," "an example embodiment," etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

1. Exemplary Operating Environment

2. Overview of Customizable Mechanically Programmable RFID Tags

55 respond by alternatively reflecting and absorbing portions of signal 104 according to a time-based pattern or frequency. This technique for alternatively absorbing and reflecting signal104 is referred to herein as backscatter modulation. Typically, such backscatter modulation may include one or more

60 alpha-numeric characters that uniquely identifY a particular tag. Readers 104a and 104b receive and obtain data from response signals 112, such as an identification number of the responding tag 102. In the embodiments described herein, a reader may be capable of communicating with tags 102

65 according to various suitable communication protocols, including Class 0, Class 1, EPC Gen 2, other binary traversal protocols and slotted aloha protocols, and any other protocols


US 7,876,222 B2 5

mentioned elsewhere herein, and future communication protocols. Additionally, tag population 120 may include one or more tags having the packed object format described herein and/or one or more tags not using the packed object format (e.g., standard ISO tags).

6 user interface (GUI), and/or a voice activated mechanism with which a user of reader 104 may interact to initiate an interrogation by reader 104.

FIG. 2 shows a block diagram of an example RFID reader 104. Reader 104 includes one or more antennas 202, a receiver and transmitter portion 220 (also referred to as transceiver 220), a baseband processor 212, and a network inter-

10 face 216. These components of reader 104 may include software, hardware, and/or firmware, or any combination thereof,

In the example of FIG. 2, transceiver portion 220 includes a RF front-end 204, a demodulator/decoder 206, and a modulator/encoder 208. These components of transceiver 220 may include software, hardware, and/or firmware, or any combination thereof, for performing their functions. Example description of these components is provided as follows.

Modulator/encoder 208 receives interrogation request 210, and is coupled to an input of RF front-end 204. Modulator/ encoder 208 encodes interrogation request 210 into a signal format, such as, for example, one of pulse-interval encoding (PIE), FMO, or Miller encoding formats, modulates the

for performing their functions.

Baseband processor 212 and network interface 216 are optionally present in reader 104. Baseband processor 212 may be present in reader 104, or may be located remote from reader 104. For example, in an embodiment, network interface 216 may be present in reader 104, to communicate between transceiver portion 220 and a remote server that includes baseband processor 212. When baseband processor 212 is present in reader 104, network interface 216 may be optionally present to communicate between baseband processor 212 and a remote server. In another embodiment, network interface 216 is not present in reader 104.

In an embodiment, reader 104 includes network interface 216 to interface reader 104 with a communications network 218. As shown in FIG. 2, baseband processor 212 and network interface 216 communicate with each other via a communication link 222. Network interface 216 is used to provide an interrogation request 210 to transceiver portion 220 (optionally through baseband processor 212), which may be received from a remote server coupled to communications network 218. Baseband processor 212 optionally processes the data of interrogation request 210 prior to being sent to transceiver portion 220. Transceiver 220 transmits the interrogation request via antenna 202.

Reader 104 has at least one antenna 202 for communicating with tags 102 and/or other readers 104. Antenna(s) 202 may be any type of reader antenna known to persons skilled in the relevant art(s ), including for example and without limitation, a vertical, dipole, loop, Yagi-Uda, slot, and patch antenna type.

Transceiver 220 receives a tag response via antenna 202. Transceiver 220 outputs a decoded data signal 214 generated from the tag response. Network interface 216 is used to transmit decoded data signal214 received from transceiver portion 220 (optionally through baseband processor 212) to a remote server coupled to communications network 218. Baseband processor 212 optionally processes the data of decoded data signal 214 prior to being sent over communications network 218.

In embodiments, network interface 216 enables a wired and/or wireless connection with communications network 218. For example, network interface 216 may enable a wireless local area network (WLAN) link (including a IEEE 802.11 WLAN standard link), a BLUETOOTH link, and/or other types of wireless communication links. Communications network 218 may be a local area network (LAN), a wide area network (WAN) (e.g., the Internet), and/or a personal area network (PAN).

In embodiments, a variety of mechanisms may be used to initiate an interrogation request by reader 104. For example, an interrogation request may be initiated by a remote computer system/server that communicates with reader 104 over communications network 218. Alternatively, reader 104 may include a finger-trigger mechanism, a keyboard, a graphical

15 encoded signal, and outputs the modulated encoded interrogation signal to RF front-end 204.

RF front-end 204 may include one or more antenna matching elements, amplifiers, filters, an echo-cancellation unit, a down-converter, and/or an up-converter. RF front-end 204

20 receives a modulated encoded interrogation signal from modulator/encoder 208, up-converts (if necessary) the interrogation signal, and transmits the interrogation signal to antenna 202 to be radiated. Furthermore, RF front-end 204 receives a tag response signal through antenna 202 and down-

25 converts (if necessary) the response signal to a frequency range amenable to further signal processing.

Demodulator/decoder 206 is coupled to an output of RF front-end 204, receiving a modulated tag response signal from RF front-end 204. In an EPC Gen 2 protocol environ-

30 ment, for example, the received modulated tag response signal may have been modulated according to amplitude shift keying (ASK) or phase shift keying (PSK) modulation techniques. Demodulator/decoder 206 demodulates the tag response signal. For example, the tag response signal may

35 include backscattered data formatted according to FMO or Miller encoding formats in an EPC Gen 2 embodiment. Demodulator/decoder 206 outputs decoded data signal 214.

The configuration of transceiver 220 shown in FIG. 2 is provided for purposes of illustration, and is not intended to be

40 limiting. Transceiver 220 may be configured in numerous ways to modulate, transmit, receive, and demodulate RFID communication signals, as would be known to persons skilled in the relevant art(s ).

The invention described herein is applicable to any type of 45 RFID tag, with suitable additional features, as described in

further detail below in conjunction with FIG. 4 and beyond. FIG. 3 is a schematic block diagram of an example radio frequency identification (RFID) tag 102 as already known to those practiced in the art. Tag 102 includes a substrate 302, an

50 antenna 304, and an integrated circuit (I C) 306. Antenna 304 is formed on a surface of substrate 302. Antenna 304 may include any number of one, two, or more separate antennas of any suitable antenna type, including for example dipole, loop, slot, and patch. IC 306 includes one or more integrated circuit

55 chips/dies, and can include other electronic circuitry. IC 306 is attached to substrate 302, and is coupled to antenna 304. IC 306 may be attached to substrate 302 in a recessed and/or non-recessed location.

IC 306 controls operation of tag 102, and transmits signals 60 to, and receives signals from RFID readers using antenna 304.

In the example of FIG. 3, IC 306 includes a memory 308, a control logic 310, a charge pump 312, a demodulator 314, and a modulator 316. Inputs of charge pump 312, and demodulator 314, and an output of modulator 316 are coupled to

65 antenna 304 by antenna signal 328. Demodulator 314 demodulates a radio frequency commu

nication signal (e.g., interrogation signal 110) on antenna


US 7,876,222 B2 7

signal 328 received from a reader by antenna 304. Control logic 310 receives demodulated data of the radio frequency communication signal from demodulator 314 on an input signal322. Control logic 310 controls the operation ofRFID tag 102, based on internal logic, the information received from demodulator 314, and the contents of memory 308. For example, control logic 310 accesses memory 308 via a bus 320 to determine whether tag 102 is to transmit a logical "1" or a logical "0" (of identification number 318) in response to a reader interrogation. Control logic 310 outputs data to be 10

transmitted to a reader (e.g., response signal 112) onto an output signal 324. Control logic 310 may include software, firmware, and/or hardware, or any combination thereof. For example, control logic 310 may include digital circuitry, such

15 as logic gates, and may be configured as a state machine in an embodiment.

Modulator 316 is coupled to antenna 304 by antenna signal 328, and receives output signal 324 from control logic 310. Modulator 316 modulates data of output signal324 (e.g., one 20

or more bits of identification number 318) onto a radio frequency signal (e.g., a carrier signal transmitted by reader 104) received via antenna 304. The modulated radio frequency signal is response signal112 (see FIG. 1), which is received by reader 104. In one example embodiment, modulator 316 25

includes a switch, such as a single pole, single throw (SPST) switch. The switch is configured in such a manner as to change the return loss of antenna 304. The return loss may be changed in any of a variety of ways. For example, the RF voltage at antenna 304 when the switch is in an "on" state may 30

be set lower than the RF voltage at antenna 304 when the switch is in an "off' state by a predetermined percentage (e.g.,

8 308 stores data, including an identification number 318. In a Gen-2 tag, tag memory 308 may be logically separated into four memory banks.

2. OVERVIEW OF CUSTOMIZABLE MECHANICALLY PROGRAMMABLE RFID

TAGS

The following sections of this specification, along with FIGS. 4 through 18, describe exemplary embodiments that incorporate the features of the inventions. The embodiment(s) described, and references in the specification to "exemplary embodiment", "one embodiment", "an embodiment", "an example embodiment", etc., indicate that the embodiment(s) described may include a particular procedure, operation, step, feature, structure, or characteristic, but every embodiment may not necessarily include the particular procedure, operation, step, feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular procedure, operation, step, feature, structure, or characteristic is described in connection with an embodiment, it is understood that it is within the knowledge of one skilled in the art to effect such procedure, operation, step, feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

While specific methods and configurations are described, it should be understood that this is done for illustration purposes only. A person skilled in the art will recognize that other configurations and procedures may be used without departing from the spirit and scope of the invention.

In particular, RFID tag embodiments are described wherein mechanical modifications to mechanically modifiable elements of the tag result in a change of a value reported by the tag. Moreover, embodiments are described wherein a

30 percent). This may be accomplished by any of a variety of methods known to persons skilled in the relevant art(s).

35 variety of customizations may be made to the RFID tag. Charge pump 312 (or other type of power generation mod

ule) is coupled to antenna 304 by antenna signal328. Charge pump 312 receives a radio frequency communication signal (e.g., a carrier signal transmitted by reader 104) from antenna 304, and generates a direct current (DC) voltage level that is output on tag power signal326. Tag power signal326 powers 40

circuits ofiC die 306, including control logic 320.

These customizations may include, but are not limited to, using an RF signal to program the RFID tag, and thereby customize the effect of the mechanical modifications on the values reported by the tag; and, applying markings or other indicia to the tag to indicate a meaning of the mechanically modifiable elements of the tag.

Charge pump 312 rectifies a portion of the power of the radio frequency communication signal of antenna signal328

Persons skilled in the relevant arts will recognize that the elements, methods, techniques, and principles of the inventions may be applied, with suitable modifications, to other

45 kinds of radio frequency reporting systems which may employ mechanically modifiable elements.

to create a voltage power. Charge pump 312 increases the voltage level of the rectified power to a level sufficient to power circuits of IC die 306. Charge pump 312 may also include a regulator to stabilize the voltage of tag power signal 326. Charge pump 312 may be configured in any suitable way known to persons skilled in the relevant art( s ). For description

50 of an example charge pump applicable to tag 102, refer to U.S. Pat. No. 6,734,797, titled "Identification tag Utilizing Charge Pumps for Voltage Supply Generation and Data Recovery," which is incorporated by reference herein in its entirety. Alternative circuits for generating power in a tag, as

55 would be known to persons skilled in the relevant art( s ), may be present. Further description of charge pump 312 is provided below.

It will be recognized by persons skilled in the relevant art( s) that tag 102 may include any number of modulators, demodulators, charge pumps, and antennas. Tag 102 may additionally include further elements, including an impedance matching network and/or other circuitry. Furthermore, although tag 102 is shown in FIG. 3 as a passive tag, tag 102 may alternatively be an active tag (e.g., powered by a battery, not shown).

Memory 308 is typically a non-volatile memory, but can alternatively be a volatile memory, such as a DRAM. Memory

3. EXEMPLARY CUSTOMIZABLE MECHANICALLY PROGRAMMABLE RFID

TAGS

FIG. 4 illustrates an exemplary RFID tag 402 according to an embodiment of the invention. Exemplary RFID tag 402 contains numerous elements in common with RFID tag 102 already described above in conjunction with FIG. 3, and therefore a discussion of these elements will not be repeated.

RFID tag 402 has a plurality of mechanically alterable elements 412, which may be tearable strips of material or punchable strips of material. Mechanically alterable elements

60 412 may be manufactured from materials which may be readily mechanically manipulated, torn, and punched, including for example and without limitation such materials as paper, cardboard, various plastics, other polymers, and other

65

tearable or punchable materials. Mechanically alterable elements 412 may be referred to

synonymously herein as mechanically modifiable elements 412, tearable elements 412, rip strips 412, punchable ele-


US 7,876,222 B2 9 10

determine the state of strips 412. In some embodiments, strip state determination module 416 may actually be a part of control logic 310, rather than being apart from control logic 310 as illustrated. The details of the configuration are not essential, provided that IC 316 contains necessary circuitry to determine the state of strips 412. For the remainder of descrip-tion such circuitry will be referred to as strip state determination module 416.

FIG. 5 presents another exemplary embodiment of a customizable, mechanically programmable RFID tag 402. Some of the elements illustrated in FIG. 5 are similar to those described above and shown in FIG. 3 and FIG. 4, and the description of those elements will not be repeated.

In FIG. 5, each conductor 414 associated with a strip 412 is

ments 412, punchable strips 412, or strips 412. Mechanically alterable elements 412 may be attached to an edge of substrate 302 ofRFID tag 402 or to a surface of substrate 302 ofRFID tag 402. Mechanically modifiable elements 412 may be rectangular in shape, as illustrated in FIG. 4 and other figures 5

herein, but may have other shapes as well, including for example and without limitation triangular, circular, semicircular, oval, ellipsoid, and other shapes as well. Different shapes and sizes of mechanically alterable elements 412, as well as different materials, may be combined on a single 10

RFID tag 402. In one exemplary embodiment, mechanically modifiable elements 412 may be strips of paper or other flexible material which may be equally sized, have a rectangular shape, and extend from the body or substrate 302 of RFID tag 402. 15 a conductive loop 414L having two leads 414A and 414B, and

a terminal part of the loop 414C. Both lead 414A and lead 414B are coupled to strip state determination module 416, and extend across or through substrate 302, and physically

Exemplary RFID tag 402 also includes conductors 414 and a strip state determination module 416. For each mechanically modifiable element 412 there is an associated conductor 414. Conductor 414 is an electrically conducting material made of materials well known in the art for use in electronics 20

into and through strip 412. Lead 414A and lead 414B of exemplary conductive loop 414L are electrically connected within the body of tag 412 at terminal end 414C. which may include, for example and without limitation, cop

per, aluminum, silver, gold, tin, and a variety of metal alloys. Each conductor 414 is coupled to strip state determination module 416, and runs along or within substrate 302, extending into a mechanically modifiable element 412.

Since mechanically modifiable elements 412 may be strips of paper or other flexible, pliable material, mechanically modifiable elements 412 will henceforth be simply referred to as strips 412. It should be noted that because, in an embodiment, strips 412 may be deliberately tom or ripped, they are sometimes referred to for convenience as "rip strips".

Strip state determination module 416 is part of IC 306. Strip state determination module 416 may be coupled to control logic 310, for example via a strip state determination bus 418. Also, found on IC 306 is a strip state register which may be used to store or report on a condition of strips 412.

In one embodiment, strip state register 420 may be part of memory 308. However, strip state register 420 may be separate from tag identification number 318, which may also be part of memory 308. In an alternative embodiment strip state register 420 may instead be a part of strip state determination module 416.

Because conductive loop 414L (comprising elements 414A, 414B, 414C) is coupled to strip state determination module 416, strip state determination module 416 may then

25 be configured to determine if conductive loop 414L remains intact, and therefore comprises a closed circuit path which will conduct a flow of electricity; or whether conductive loop 414L has been mechanically disrupted, and therefore no longer comprises a closed circuit path and may no longer be

30 configured to conduct a flow of electricity. Not all of the strips 412, and their associated conductive

loops 414L, are actually illustrated in FIG. 5 as being electrically coupled to strip state determination module 416. For ease of illustration, only partial connections are shown, along

35 with ellipses indicating that the connections continue. This practice is repeated in some other figures as well. In fact, each strip 412 may have an associated conductor 414 which is electrically coupled with strip state determination module 416, for example, by extending on the surface of or through

40 the body of strip 412, along or within substrate 303, and terminating at strip state determination module 416. However, some strips may intentionally not have an associated conductor 414 and may be present only for other indicating Strip state determination module 416 is configured to

determine the state of strips 412. Each strip 412 may be in a state in which it maintains the electrical conductivity of its 45

associated conductor 414. However, mechanically altering strip 412 may disrupt the flow of electricity through its associated conductor 414.

purposes.

4. MECHANICAL MODIFICATION OF EXEMPLARY RFID TAGS

There are a number of ways in which a strip 412 may be mechanically modified in order to disrupt the flow of electricity in its associated conductor 414. For example, among other possible means, strip 412 may be physically tom or ripped, or strip 412 may be punched using a conventional mechanical hole puncher or similar device. Strip state determination module 416 is configured to electrically sense the conductive state, which may be either conductive or nonconductive, of each conductor 414 associated with each strip 412.

Conductor 414 may be embedded within strip 412, or may run along a surface of strip 412, or may be partly embedded within strip 412 and run partly along a surface or surfaces of strip 412.

While strip state determination module 416 is shown as separate from control logic 310 and coupled to control logic 310 (for example, by bus 418), this is principally for purposes of clarity of presentation. In embodiments, there needs to be some circuitry within RFID tag 402 which is configured to

FIG. 6 shows another exemplary RFID tag 402 embodi-50 ment. Some of the elements shown in FIG. 6 have already

been described in conjunction with other figures above, and description of those elements will not be repeated.

As illustrated in FIG. 6, exemplary RFID tag 402 may include strips 412 which are rippable. Rippable may be

55 viewed as synonymous with tearable. The rippable strips have beenlabeled412R, where R is for "rippable". Each strip 412R may have an optional perforation 502. Perforation 502 may be an actual perforation, meaning holes or similar elements, such as slits or seams, which have been cut through strips 412,

60 or perforations 502 may simply be dotted lines or other demarcation printed on strips 412 as an indication of a place where strips 412 may be torn or cut by a user.

Each strip 412R has an associated conductive loop 414L as previously described, where conductive loop 414L has leads

65 414A and 414B coupled to strip state determination module 416, and extending up to and into rip strip 412R. Further, and as previously described, terminal element 414C of conduc-


US 7,876,222 B2 11 12

tive loop 414L completes the connection between leads 414A and 414B. In particular, FIG. 6 highlights that terminal element 414C, and a segment 414X of conductive loop 414L closer to substrate 312 than terminal element 414C, are on opposite sides of a boundary defined by perforation 520 on rip 5

strip 412R, with terminal element 414C on the far side of perforation 520 from substrate 312.

mechanical alterations as appropriate) of the respective strip 412 results in a change in the bit value of the coupled bit 702. Persons skilled in the relevant arts will recognize that such coupling between a strip 412 and a bit 702 may be via a direct or indirect electrical connection, or via a logical coupling mediated through such components as strip state determina-tion module 416, control logic 310, or similar control components ofiC 306, or through a combination of the above. Consequently, if rip strip 412R were to be tom, ripped,

severed, or separated at the location of or substantially at the location of perforation 502, then terminal component 414C 10

would be removed. This in tum would leave leads 414A and

FIG. 8 shows another exemplary RFID tag 402 embodiment. Some elements illustrated in FIG. 8 have already been described above, and a discussion of these elements will not be repeated. 414B with no electrical connection. As a consequence, an

electric current could no longer be conducted in a closed circuit from lead 414A to 414B. This lack of conductivity, reflecting an open circuit path, would be an electrical state which is detectable by strip state determination module 416.

Mechanical modification of exemplary RFID tag 402 has been illustrated and described here with respect to a method of tearing or ripping an exemplary rip strip 412R. However, it will be apparent to persons skilled in the relevant arts, and will be described further below, that other means may also be employed to mechanically modifY strips 412 in such a way as to alter the electrical states of associated conductors 414.

5. DETERMINATION OF STRIP STATES OF EXEMPLARY RFID TAGS

FIG. 7 illustrates further aspects of exemplary RFID tag 402. FIG. 7 illustrates some elements of exemplary RFID tag 402 which were described previously above, and description of those elements will not be repeated.

In FIG. 7 certain elements already described have been redrawn or rearranged for clarity and without any substantial change in functionality. For example, all eight of strips 412R are now illustrated with their associated conductors 414 directly coupled to strip state determination module 416. In addition, strip state register 420 has now been moved from memory 308 to be within strip state determination module 416. Persons skilled in the relevant arts will be recognize that the particular placement of strip state register 420 is not essential to the actual functionality of the invention disclosed herein.

Strip state register 420 is now illustrated as having a plurality of bits 702. Each bit 702 may store a value which, in an embodiment, may be a 1-bit value of zero or one. Further, each bit 702 has an identifYing address, numbered 0, 1, 2, 3, 4, 5, 6, and 7, which associates each such bit with a corresponding strip 412R, where strips 412R have also been labeled 0, 1, 2, 3, 4, 5, 6, and 7.

In an embodiment, each bit 702 of strip state register 420 has a default value. A bit 702 may have a default value of" 1 ", which is associated with an intact strip 412. Further, upon mechanical alteration of strip 412 such that strip 412 is no longer intact, conductive loop 414L associated with the strip is no longer configured to conduct electricity. This change of state may be detected by strip state determination module 416. Consequently, the associated bit 702 of strip state register 420 may change its state from a "1" to a "0", the "0" value indicating that the strip 412 is no longer intact. In an alternative embodiment, the default value of a bit 702 representing an intact strip 412 may be a value of "0", and therefore the value which indicates a mechanically changed strip 412 may be a value of"1".

Effectively, then, each bit 702 of strip state register 420 may be effectively coupled to a respective strip 412 in such a manner (logically, direct connection, etc.) that a mechanical alteration (for example, ripping, tearing. punching, or other

A first strip 412S has been tom, ripped, cut, or otherwise severed at perforation 502. Strip 412S therefore now has two

15 parts, 412S1 and 412S2. (In "412S", the letter'S' stands for "severed".) 412S1 is the part which has been severed from the strip. It is illustrated in the figure for purposes of exposition, but from a functional or operational stand point in relation to RFID tag 402, severed strip part 412S1 may serve no further

20 use, and in operational practice may be disposed of by a user. (For some organizational purposes, such as auditing a process associated with RFID tag 402 or otherwise auditing use of RFID tag 402, severed strip part 412S may be retained or stored; alternatively, some identifier or indicia (discussed

25 further below) from severed strip part 412S may be recorded by a user in a journal or database before severed strip part 412S is disposed of by a user.)

412S2 is a stump of strip 412S which remains attached to substrate 302. Running through strip stump 412S2 is conduc-

30 tor 414S which is now composed of two separate parts that are no longer electrically connected. Strip state determination module 416 is configured to detect that a current no longer can flow through conductor 414. On this basis, logic within strip state determination module 416 determines that strip 412S

35 has been modified (that is, severed). In tum, strip state determination module 416 changes the state of a bit 702 associated with the tom strip 412S. As shown, for the bit 702 whose address is bit 0, and which is associated with the modified strip 412S at position zero, the bit 0 now has a value of "0"

40 rather than "1". The value of "0" reflects the fact that strip 412S is physically severed.

In this way, a mechanical action on the part of the user, namely the severing of strip 412S, is now reflected in an appropriate or matching bit 702 whose address is bit 0 of strip

45 state register 420. It may further be seen that the eight bits 702 of strip state register 420 now have a bit pattern 802 which corresponds to the state of all the strips 412R. For example, it can be seen that the 0 strip is severed or modified, whereas strips 1 through 7 remain intact. The corresponding bit pattern

50 802 shows the 0-address bit as having the value of "0" whereas bits at bit addresses 1-7 each have a value of "1", reflecting the fact that the associated strips 412 remain intact.

FIG. 9 is another view of exemplary RFID tag 402, further illustrating the exemplary system and method described in

55 conjunction with FIG. 8. Some elements of exemplary RFID tag 402 described in conjunction with FIG. 9 are the same as those elements previously described above, and description of those elements will not be repeated.

In FIG. 9, of the eight strips 412, both strip 0 and strip 3 60 have been mechanically modified, and specifically have been

torn at perforations 502. So, strips 0 and 3 are tom, where strips 1, 2, 4, 5, 6, and 7 remain intact. It can further be seen that strip state determination module 416 has detected the condition of the strips and that this is reflected in strip state

65 register 420. Specifically, strip state register 420 shows a bit pattern 802

(reading from left to right): "0, 1, 1, 0, 1, 1, 1, 1" wherein this


US 7,876,222 B2 13 14

bit pattern 802 corresponds to the status of strips 412, and wherein a "0" indicates a torn or modified strip and a "1" indicates an intact strip. In this way, bit pattern 802 reflects the status of strips 412. Persons skilled in the relevant art will recognize that other patterns of strips 412 as intact or torn can 5

be similarly represented in bit pattern 802 of strip state register 420.

radio control message may be used to change the default value of some or all of bits 702 of strip state register 420.

In an alternative embodiment, one or more of strips 412 may be used to change the default values of the bits 702 in strip state register 420. For example, a bit control strip 412B ("B" standing for "bit") may be used to change the default values of some or all of the bits in strip state register 420. In one embodiment, the effect of mechanically modifYing bit control strip 412B may be hard coded or pre-wired into the

In addition to the capability to simply detect the state of the strips 412 and to reflect that state in strip state register 420, strip state determination module 416 and/ or control logic 310 of RFID tag 402 may be further configured for additional forms of detection and processing.

10 control logic of exemplary RFID tag 402a. In that case, mechanically modifying the appropriate bit control strip 412B, such as by severing bit control strip 412B, will have a predetermined effect of changing the default value of speci-For example, strip state register 420 and/or control logic

310 may be configured to detect a particular bit pattern of strip state register 420, and further be configured to report or to 15

send an alert or an alarm to an RFID reader upon a detection

fied bits 702 of strip state register 420. In an alternative embodiment, aspects of both of the pre-

viously described methods may be combined. For example, first, a message may be received at RFID tag 402a via a radio frequency link, wherein the message indicates which of the bits 702 of strip state register 420 may have their default

of a preprogrammed bit pattern. Such a pattern may be stored in memory 308, having been transferred to exemplary RFID tag 402 from an RFID reader in a mam1er well known in the art. For example, control logic 310 or strip state determination module 416 may be configured to compare the bit pattern 802 of strip state register 420 to a previously stored bit pattern, and upon detection that the two are the same, may send an alert to an RFID reader.

20 values modified. However, upon receipt of this message, the default values of the associated bits 702 are not modified. Instead a reference to the appropriate bit addresses and new default values is stored in a non-volatile memory associated with memory 308. At a later time, if a user chooses to modify

25 the default values of the bits according to the previously provided instructions, the user may elect to tear the appropriate bit control strip 412B. Only at that time will the default values of the designated bits 702 of strip state register 420

Similarly, algorithms or logic which may be programmed into control logic 310 or strip state determination module 416 may be used to determine an order in time or a sequence in time in which strips 412 are modified. Control logic 310 or strip state determination module 416 may be further configured to send an alert or alarm if strips 412 are modified in a 30

specified order, or if strips 412 are modified in an order other than a preferred order. As will be described further below, such a feature may be valuable for process control purposes.

actually have their default values changed. As can been in the exemplary RFID tag 402a illustrated in

FIG. 10, when strip 412B (shown here as the 0 strip) is mechanically modified, its associated bit 702 may be modified as well, changing from "1" to "0". In addition, it may have been preprogrammed via a radio frequency message that

6. CHANGING VALUES ASSOCIATED WITH STRIPS OF EXEMPLARY RFID TAGS

35 bits 702 at bit addresses 4 and 5 should have their default states changed from 1 to 0. Therefore, even though strips 412 number as strips 4 and 5 remain intact, a new default value of "0" is shown for bits 702 at bit addresses 4 and 5 in strip state FIG. 10 illustrates another exemplary embodiment of an

RFID tag 402a according to the. Exemplary RFID tag 402a has some elements in common with tags 102 and 402 already 40

described above, and a discussion of these elements will not

register 420. In an alternative embodiment, it may be possible to set a

state of a bit702 such that the bit 702 stays at a fixed value (for example, "0" or one (1)) irrespective of whether the associated strip 412 is physically modified. Analogous to description already presented above, such a condition may be

be repeated. Exemplary RFID tag 402a has a bit value control module

1004. In one embodiment, bit value control module 1004 may be separate from control logic 310, and may for example be part of strip state determination module 416, and may further be coupled to control logic 310 via a bus 1006 or via other means. In an alternative embodiment, bit value control module 1004 may be a part of control logic 310, or may be implemented via logic within control logic 310.

As noted above, bits 702 of strip state register 420 may have a default value which is associated with an intact strip 412. For example, for a bit 702 corresponding to a strip 412,

45 directly progrmed via an RF link to tag 402. Alternatively, such a condition may be preprogrammed as a possible state of tag 702, but may only be made an active state of tag 702 when triggered by a mechanical modification of a bit control strip 402B.

50

a bit value of"1" may be the default value indicating an intact strip 412, while "0" may indicate a ripped or tom strip 412S. 55

If a bit 702 is set to remain at a fixed value even when the strip 412 normally associated with that bit 702 is mechanically modified, then it may be that the bit 702 and the associated strip 412 have been effectively decoupled. In this sense, value control module 1004 may also be viewed as or may be working in conjunction with a bit/strip coupling control module, capable of decoupling and possibly recoupling a For some purposes however, it may prove useful to change

the default values associated with some or all bits. In one embodiment, a control message may be sent from an RFID reader to RFID tag 402a, the message being received in the conventional mam1er via antenna 304, processed through demodulator 314 and control logic 310, and then sent via bus 1006 to bit value control module 1004. The message may indicate that certain bits 702 are to have a default value of"O" instead of"1". Or, if the initial standard default value for an intact strip 412 happens to have been "0", such a message may tell bit value control module 1004 to change the default value from "0" to "1". Under either set of circumstances, a simple

strip 412 and an associated bit 702. In an alternative embodiment, value control module 1004, further understood as a bit/strip coupling control module, may be further configured

60 to reassign which bits 702 are associated with which strips 412.

Persons skilled in the relevant arts will appreciate that such bit/strip coupling control may be implement through a variety of means including, for example and without limitation, vari-

65 ous configurations of logic gates, various circuit/memory element mapping schemes, and various forms of control logic. Further, such means may be implemented within strip


US 7,876,222 B2 15

state determination module 416, value control module 1004, control logic 320, other memory control circuits or modules (not illustrated), or similar components ofiC 306, or through a combination of the above.

7. FURTHER EXEMPLARY RFID TAGS AND FEATURES THEREOF

FIG. 11 is another diagram of an exemplary RFID tag 402 according to the, presented in part to show the elements drawn approximately to scale. Seen in the figure is IC 306, antenna 304, conductors 414, substrate 302, and strips 412, which in this case are rip strips 412R. It can be further seen from the figure that the number of strips need not be eight strips, as were shown in the preceding figures. Shown here are six rip strips 412R.

Persons skilled in the relevant arts will appreciate that more

16 hold strip 412 against substrate 302 may also be used to hold strips 412 against items or objects to be monitored.

Adhesive 1204 may enable a strip 412 to be attached to an object, so that the object may be monitored via strip 412. In

5 other words, by physically attaching strip 412 to an object by means of the adhesive substance, a movement or change of the object may result in a tearing or other physical alternation of strip 412. In that way, the movement or change of the object can directly trigger the mechanical change of strip 412, and

10 hence signal that the object has been moved or modified. FIG. 12B presents another view of exemplary RFID tag

402, this view showing a reverse side from the side shown in FIG. 12A. The side shown in FIG. 12B may be an entire adhesive surface 1206, which may be then used to attach the

15 entire RFID tag 402 to an item to be monitored. A cover (not shown) may be provided to protect adhesive 1206 until it is put into use. This cover may be provided on top ofRFID tag 402. The cover may then be stripped away at such time as or fewer strips may be used. Persons skilled in the relevant

arts will also appreciate that the strips need not all be all on the same side of RFID tag 402, and indeed the strips may have 20

different sizes in relation to each other or in relation to the tag

RFID tag 402 is to be put into use and attached to an object. FIG. 13 shows another exemplary RFID tag 402b embodi-

ment. Exemplary RFID tag 402b may be presumed to be similar in many respects to exemplary RFID tags 402 already described above. However, RFID tag 402b does not employ tearable strips 412. Instead, RFID tag 402b may employ

as a whole. For example, an RFID tag 402 may have a single strip 412 on each edge of a rectangular substrate 302, for a total offour strips 412.

A strip 412 of exemplary RFID tag 402 may have a strip indicia 1104 (also referred to herein, synonymously, as "identifier 1104" or "labeling 1104"). Strip indicia 1104 may be associated with or used to indicate a purpose of strip 412. In one embodiment, strips 412 may come with a default strip indicia 1104 (for example, a factory-applied indicia or a manufacturer-applied indicia) which may, for example, be a simple numbering scheme such as that shown in FIG. 11. In this way each strip may be associated with a number, such as, '1 ', '2', '3', '4', '5', and '6'. Furthermore, a purpose or use with which each strip 412 is associated may be independently assigned the appropriate number corresponding to the strip 412. Other default strip indicia 1104, such as graphic symbols or color coding, may be employed as well.

In an alternative embodiment, strip 412 may be configured to accept alternative or additional strip indicia 1104. Such alternative or additional strip indicia 1104 may be applied by a user of RFID tag 402 in an office, factory, or other field setting, and may be referred to as "field-applied indicia" (also referred to herein, synonymously, as "field-applied identifier" or "field-applied labeling"). For example, it may be possible to write on strip 412 with a pen, pencil, or marker pen. Or it may be possible to actually attach a set oflabels (for example, paper labels with adhesive backing) to strip 412. Such labels may be provided as part of a package with RFID tag 402. Other aspects of applying strip indicia 1104 to RFID tag 402 will be described further below in conjunction with FIG. 15 and FIG.16.

25 punchable strips 412P. It will be apparent to persons skilled in the relevant arts that punchable strips 412P would be similar in many respects to tearable strips 412R. In particular, punchable strips 412P would have running through them or along their surface a conductor 414 (not shown in FIG. 13), where

30 the continuity of conductor 414 results in a first state of an associated bit, and a discontinuity of conductor 414 results in a second state of an associated bit.

In the case of a punchable strip 412P, the discontinuity of associated conductor 414 is achieved by physically punching

35 a hole 1304 in the strip 412P. Because punchable strips 412P do not need to be torn, they therefore do not need extend from the substrate 302 of the RFID tag. Instead, punchable strips 412P may serve simply as an extension of substrate 302 or may be continuous with substrate 302 of RFID tag 402b.

40 However, in an alternative embodiment, punchable strips 412P may extend from substrate 302 in a manner similar to that seen previously for rippable strips 412R.

A tag indicia 1302 may be present to provide instruction or some message. Tag indicia 1302 may indicate a purpose or

45 use of tag 402, or may indicate a means for altering the tags, such as punching it or tearing a strip, or tag indicia 1302 may provide other useful information to a user of tag 402. Tag indicia 1302 may be affixed by means of a physical label (for example, a paper label with an adhesive backing) which is

50 attached to RFID tag 402. Tag indicia 1302 may be physically printed on RFID tag 402 using ink. Tag indicia 1302 may be hand written or drawn onto RFID tag 402.

FIG. 12A illustrates a set of strips 412 where two of the strips have already been put into use, one of them (strip 121 0) being illustrated as already ripped or torn, and another (strip 55

1212) in use or ready to be used but not yet torn, while four additional strips 1214 are flush against the substrate 302 of RFID tag 402.

8. APPLICATIONS OF EXEMPLARY CUSTOMIZABLE, MECHANICALLY

PROGRAMMABLE RFID TAGS

FIG. 13 further illustrates a practical application of the present system and method. Exemplary RFID tag 402b may be used for keeping track of a patron's activities in an amusement park or similar environment, such as a zoo or other entertainment setting. As another example, a user may purchase a ticket which may cover a full price of all possible activities that the user might choose to engage in during a day at a park or amusement center. Each user is also issued a physical ticket in the form of RFID tag 412b, which has suitable strip indicia 1104 imprinted on it for each possible

In one embodiment, it may be possible to use an adhesive substance (not shown) to hold the strips 412 against substrate 60

302 ofRFID tag 402, so that the tags may be held out of way until they are put into use. In addition, an adhesive 1204 may be placed on the exposed side of strips 412 for use in attaching the strips 412 to items or objects to be monitored. Such an adhesive 1204 may be covered by a piece of protective mate- 65

rial (not illustrated), which may be removed by a user. In an alternative embodiment, the same adhesive which is used to


US 7,876,222 B2 17

ride or event. As the user participates in the various activities, such as a monorail ride or a sky ride, a ticket taker at each activity or event does not need to actually accept money from the patron. Furthermore, there is no need to actually have an RFID reader at each location to record the patron's activity, 5

which saves significant expense. Instead, as the user participates in an event, such as a monorail ride or sky ride, the appropriate matching strip 412 is punched.

18 Yet another means to apply indicia 1104, 1302 to a tag 402

may be via custom labels. For example, labels similar to those used for mailings for envelopes or similar purposes may be provided. However, these labels may be custom designed to be an appropriate size to be affixed to strips 412 or substrate 302 ofRFID tag 402. These labels could be part of a sheet of labels of the kind which may be fed through a laser printer or an ink jet printer, so that large numbers of labels could be mass printed and then affixed to the appropriate strips 412 or substrate 302 ofRFID tag 402.

In an alternative embodiment, and with the emergence of thin film flexible microprocessors, it may be possible to actually design RFID tags 402 according to the present system and method where the tags themselves come affixed to sheets,

At the end of the day, and as per instructions in tag indicia 1302, the user returns to an ATM machine for a refund for 10

unused items. The user brings the tag 402b, which is also their ticket to the ATM machine. The ATM machine detects which holes 1304 have been punched and which have not been punched. The unpunched holes (in this case, the safari lunch and the bumper boats) indicate events, services, or activities which the patron did not take advantage of. The ATM machine can then calculate an appropriate refund due to the patron and provide the patron with that refund.

15 where the sheets may be feed through either ink jet printers, laser printers, or similar printers. In that event, and optionally with the help of pre-designed templates for use with a word processing program or similar software, appropriate indicia

A feature described above in conjunction with FIG. 10, namely the feature of changing default bit states or fixing a bit 20

state associated with strips 412, may be utilized in these circumstances. For example, although not illustrated, it is possible that the user may show up at the park with a discount ticket which entitles him or her to take certain rides or participate in certain events for free. In that case, it may be 25

desirable to set a default state of a bit to a different value, or fix the value of a bit, and thereby indicate that a particular event is for free for that patron.

FIG. 14 illustrates another exemplary application of an RFID tag 402. For the application shown, it may not matter 30

whether strips 412 are rippable strips or punchable strips. In some embodiments, it may be possible to use punching on strips 412 on which are otherwise rippable.

FIG. 14 shows an exemplary tag useful in an assembly line 35

process, perhaps one associated with automobile repair or automobile assembly. Strip indicia 1104 on each of the strips 412 indicates the specific stages of the process. Tag indicia 1302 indicates the result that will occur. Specifically, tag indicia 1302 indicates that an alarm will sound if a process is

40 performed in an incorrect order. In this way, the capacity of tag 402 to be progrmed for a desirable tearing order of the strips (or punching order of the strips) can be used to monitor

1104, 1302 could be generated on a computer screen and then printed directly onto the RFID tags 402 of the present system and method.

FIG.15 illustrates exemplary strip indicia 1104 which may be employed. These include: text, shown as 1104A; numbering 1104B; special codes 1104C; special patterns 1104D; colors 1104E (represented here by the words 'Red', 'Green', 'Blue', etc., but in actual application actual colors may be used); bar codes 1104F; symbols 1104G; and geometric figures 11 04H. Also employable for the present purpose may be tactile indicators 11041. For example, raised dots (illustrated as three dark round dots) of the kinds used for brail may be employed as indicia or labeling on the strips 412 of the RFID tags 402. Other strip indicia 1104 may be employed as well.

FIG. 16 illustrates some exemplary specific ways in which strip indicia 1104 may be attached to strips 412. For example, a label1602 may be attached to a label receiving surface 1604 of a strip 412. Similarly text may be imprinted directly onto a printable surface or text receiving surface 1606 of a strip 412. Finally, a malleable, ductile, moldable, or pliable surface 1608 of a strip 412 may be impressed with the imprint of a texture or demarcation that can be sensed in a tactile manner. Alternatively, raised elements or other tactilely-sensible ele-ments may be attached to surface 1608 via glue, adhesive, or other means.

In an embodiment, RFID tag 402 proper may be supplied a process and make sure that steps are performed in a correct order.

In a default configuration it may be that RFID tag 402 expects strips 412 to be tom in a fixed order from left to right, or from a strip numbered from 1 up to a highest number strip. However, in one embodiment, the desired order may be modifiable via RF programming.

45 with a sheet or sheets of factory-labeled labels of a size suitable for attachment to strips 412 and to the substrate 302, where such labels may come with preprinted text, symbols, color markings, geometric shapes, icons, or other indicia like those described above, suitable for a variety of applications.

50 As indicated above, an advantage of the present system and

method is the capability of applying labeling 1104 or otherwise utilizing indicia 1104 on strips 412 in such a way as to indicate a meaning, purpose, or use of each strip 412. As already noted, strip indicia 1104 may be factory-or-manufac- 55

turer applied to RFID tags 402, or may be field-applied by a user ofRFID tags 402.

9. METHODS ASSOCIATED WITH CUSTOMIZABLE, MECHANICALLY

PROGRAMMABLE RFID TAGS

FIG. 17 is a flow chart of an exemplary method 1700 to monitor a status of an item or to monitor a process using a customizable, mechanically programmable RFID tag. Method 1700 may entail certain optional steps which will be covered after covering the primary steps. The method begins

Strip indicia 1104 may be applied in any of a variety of ways. As already noted, strips 412 may come pre-manufactured with a default strip indicia 1104, which may for example be a simple numbering. For example, ifthere are eight strips 412 associated with tag 402, each strip 412 may be labeled with a number 1-8. In addition, for purposes of individual applications, it may be possible to apply a tag indicia 1302 or strip indicia 1104 to an individual tag 402 or strips 412 of a tag with text, lettering, or other indicia by hand using a pen or pencil or a marker pen.

60 at step 1702. At step 1705 an RFID tag 402 is assigned to the item or

process. In the case of an item, assigning the RFID tag 402 to the item may entail at some point physically attaching the RFID tag 402 to the item. The RFID tag 402 may be of the

65 type described above in conjunction with various figures, including FIG. 12A and FIG. 12B which illustrate the use of adhesives for purposes of attaching RFID tags. Assigning an


US 7,876,222 B2 19

RFID tag 402 to a process may in practice entail placing the tag in possession of person monitoring the process. It may instead entail affixing the tag to a monitoring device associated with the process, or to an assembly line associated with the process, or to a monitoring station associated with the 5

process, or to some type of conveyance associated with the process.

Step 1710 entails associating strips 412 ofRFID tag 402 to process steps or with conditions or statuses of the item.

20 appropriate respective strip 412 of RFID tag 402 will be automatically mechanically modified. In this way it is possible to that no human intervention may be needed to modifY tag 402 upon the performance of the step or upon determination of the appropriate status of an item.

In optional step 1765 of method 1700, which may follow step 1710 and precede step 1715, strips 412 of tag 402 maybe labeled to indicate an association between the strips 412 and particular process steps or an association between strips 412

In step 1715 of method 1700, upon performance of a step or upon determination of an appropriate status of an item, a mechanical modification is made to the appropriate strip 412 ofRFID tag 402. For example, an appropriate strip 412 may

10 and specific items statuses or item conditions. FIG.18 is a flow chart of an exemplary method 1800 which

illustrates in more detail the steps that may be entailed in steps 1750 or step 1755 of method 1700, wherein one or more bits 702 of RFID tag 402 may be set to fixed values or may have be torn or punched to indicate the performance of the step or

the determination of the appropriate item status. In step 1720, which may be performed at the conclusion of

an entire process or may be performed repeatedly, RFID tag 402 is read, typically with an RFID reader, to determine the

15 their default values changed.

bit status of the register 420 which monitors the strip 412. Finally, in step 1725 a determination of the status of the 20

process or item is made based on bit pattern 802. This determination may be made by a person or by automated software or by other means.

Method 1700 of monitoring an item's condition or monitoring process steps has several optional steps. As already 25

noted above, step 1710 (which is a non-optional step) entails associating strips 412 ofRFID tag 402 with respect to process steps or item conditions/statuses.

Following step 1710, in step 1750 it may be desired to render unchangeable the values associated with certain bits of 30

RFID tag 402. Thus, RFID tag 402 may have logic which enables tag 402 to be programmed in such a way that specific bits will not change values even when the associated strip 412 is mechanically modified. Similarly, in optional step 1755 the default values associated with bits of RFID tag 402, where 35

those bits in turn are associated with strips 412, may be set so that their default values are changed from the original default values (for example, factory-set default values) to new default values.

As an example of the application of these optional steps, 40

consider for example an assembly line process where a part is to be modified in a certain way according to steps which we may label A, B, C and D. Suppose at some point that a change is made to the parts which are ordered as part of the assembly line process. As a result of the change in the order, the parts 45

are now delivered with a result of step B already completed as the parts are delivered to the assembly process. That is, the parts as ordered from a manufacture may have already had step B applied to them.

It is therefore desirable that RFID tags 402, which may 50

already have been customized for the application at hand, should have the appropriate strip 412 tom, such as a strip 412 which may correspond to step B. However, there is the possibility that users may neglect to tear the strip 412 associated with step B, and thus may fail to indicate that step B was 55

already applied to parts as delivered. A way to avoid this problem is to program the RFID tags 412 in advance. Specifically, the RFID tags 412 may be programmed such that the bit 702 associated with the second strip, and therefore with step B, is automatically and permanently set to an unchange- 60

able value which indicates that step B was inherently completed (since the parts were delivered with step B already applied).

In optional step 1760 of method 1700, which may follow step 1710 and precede step 1715, RFID tag 402 or strips 412 65

of tag 412 may be configured so that upon performance of a step, or upon determination of an appropriate status, an

In an exemplary embodiment, method 1800 starts at step 1802.

In step 1805, RFID tag 402 may accept via a radio frequency link an identification of a bit or bits 702 of strip stage register 420.

In step 1810, RFID tag 402 may accept via the same radio frequency link an indication of whether the designated bits 702 are to be given a different default value from the standard default value (for example, a factory preset default value), or whether those bits 702 are to be fixed permanently at a specific value irrespective of whether the associated strip 412 is mechanically modified.

In one embodiment of method 1800, the method continues along path 1812 to arrive at decision 1820.At 1820 a decision is made as to whether the indicated bits 702 are to be assigned a new default value, or whether the indicated bits are to be assigned a fixed (that is, an unchanging) bit value.

Path 1822 indicates the case where the default value of the indicated bits 702 is to be modified. At step 1830 the RFID tag 402 modifies the default value of the indicated bit or bits 702. If at decision box 1820, it is determined that the indicated bits 702 are to be assigned a fixed bit value 702, the method continues according to path 1824. Path 1824 leads to step 1835. In step 1835 the value of the indicated bits 702 is fixed so that the bit or bits 702 do not change even when the associated strip 412 is mechanically modified.

Returning to step 1810, and in an alternative embodiment, the method of 1800 may continue along path 1814. Here, at decision step 1816, a determination has to be made as to whether or not the indicated changes to the bit or bits 702 should be applied at all. The decision is made based on the condition of a designated bit control strip or factory-determined bit control strip 412B. A detection is made as to whether or not there has been a mechanical modification, such as a punching or tearing, of the bit control strip 412B.

If bit control strip 412B has not been mechanically modified (that, torn, ripped, punched, etc.), the method continues along the path of 1817 where the mechanical condition of the bit control strip continues to be monitored. That is to say, step 1816 continues to loop and make a determination as to the status of the bit control strip 412B. If the bit control strip 412B has been mechanically modified, method 1800 continues along path 1818. This arrives again at decision box 1820, already described above, where a determination is made as to whether to modifY the default value of the bits 702 or to fix the default value of the bits 702.

Persons skilled in the relevant arts will recognize that the exact steps described for methods 1700 and 1800, as well as the order in which the steps are performed, are exemplary only. Methods 1700 and 1800 may be modified in various respect, including having more or fewer steps, and have steps


US 7,876,222 B2 21

performed in an order other than that illustrated, while still remaining within the scope and spirit of the.

10. ALTERNATIVE EMBODIMENTS

22 Other mechanically modifiable elements 412 which may

be toggled from an on-state to an off-state and back again, repeatedly, may also be envisioned. For example, mechanically modifiable elements 412 may be of a nature such that a small hinged or detachable clip may be placed across them. The clip may serve the purpose of completing an electrical connection or breaking an electrical connection. In this way, again it may be possible that a mechanically modifiable element 412 can be repeatedly modified from a first state to a

The invention has been described with respect to a number of exemplary embodiments. Alternative embodiments may be envisioned within the scope and spirit of the invention as described herein, and as further defined by the appended claims. Some of these alternative embodiments are described below.

10 second state. In conjunction with this, of course, a corresponding bit 702 of register 420 may be set repeatedly from a first state to a second state and back again, as suites the needs of a process, item, or other thing being tracked via RFID tag 402.

The operation of the invention has been described with respect to a register comprised of a number of bits 702, wherein each bit of the register 420 corresponds to a mechanically modifiable element 412 of the RFID tag 402. Persons 15

skilled in the relevant arts may associate the concept of a "register" with specific types of memory registers well known in the art, which are frequently used in computer hardware and similar technologies. For example, registers may be comprised of a series of bits wherein each bit value may be 20

represented by an electrical state of a transistor or capacitor, or a magnetic state of a magnetically active material, or simi-lar electrical or physical state of a hardware component.

It should be understood that a register is any type of elec-25

tronic circuit or any configuration of electronic elements which may be configured to represent a state of a mechanically modifiable element. Therefore, a register need not comprise the type of registers typically associated with microprocessors or with other computer memory systems, although a

30 register may be of the type conventionally associated with microprocessors and other computer memory. However, any circuitry, element, or component capable of representing or reporting at least two states of a mechanically modifiable element is sufficient to define a register.

35 A variety of mechanically modifiable elements 412 may be

associated with RFID tag 402 within the scope of the invention. While the invention has been described with respect to strips 412 which may be torn or may be punched, other types of mechanically modifiable elements may be envisioned as 40 well.

The invention has been described with respect to an RFID tag 402 wherein the register 420 or other register elements which tracks the state of the mechanically modifiable elements is construed to be separate from the memory 308 which holds an identification number 318 for the RFID tag. However, in an alternative embodiment, it may be that some or all of the mechanically modifiable elements 412 are employed to modifY part or all of the identification number 318 of the RFID tag 402 itself.

The invention has also been described with respect to an RFID tag 402 which has a single register 420 and a single type of mechanically modifiable element 412 which is used to modifY the state ofbits 702 in the strip state register 420. In an alternative embodiment, RFID tag 402 may have more than one register 420, where each register may serve a different purpose in terms of flagging or identifYing or tracking different types of information. Each register 420 may have associ-ated with it its own set of mechanically modifiable elements 412 such as, but not necessarily limited to, the strips 412 already described above.

In an alternative embodiment, more than one type of mechanically modifiable element 412 may be employed. For example, for some applications it may be convenient to have some mechanically modifiable elements 412 which are tearable or rippable, and other mechanically modifiable elements which are punchable. Other additional types of mechanically modifiable elements may be employed as well.

One or more of the mechanically modifiable elements 412, such as one or more tearable strips 412R or punchable strips 412P may be employed to trigger changes to a meaning or

For example, a mechanically modifiable element 412 may comprise multiple layers, such as possibly two layers of material which may be in contact with each other as configured at the factory, and therefore may appear as a single strip or single element. However, it may be the case that by separating two layers of such a strip 412, for example, by peeling apart two layers which are stuck to each other, an electrical contact is broken. In this way the peeling action, by breaking the electrical contact, modifies the mechanical state of the element, and therefore also modifies the electrical state of the element. Therefore the state can be detected and represented in a bit 702 of the register 420 as previously presented above. Moreover, an advantage of the mechanically modifiable element 412, as just described, may be that in addition to separating two layers of the element 412, it may be possible to join the two layers back together again, thus reestablishing the electrical path. As a result it may be possible to toggle a bit from one state to another state, and then back again, repeatedly.

45 condition of other bits 702 in the register 420 which do not correspond strictly to the particular mechanically modifiable element 412 so employed. In alternative embodiments, yet more complex interactions may be envisioned between the logical states which are represented by the alternative

50 mechanical conditions of the mechanically modifiable elements 412. Persons skilled in the relevant arts will recognize that any number of logic circuits, logic gates, or logic elements may be employed to implement a variety of logical outputs, which may result from various combinations of the

55 mechanically modifiable elements 412 and the various mechanical states of the mechanically modifiable elements 412. Moreover, such logic circuits, logic gates, or logic elements may themselves be customizable, that is, field pro-grammable, via RF signals or other means.

Each mechanically modifiable element 412 typically has two states, namely a state where an associated circuit loop 414 L is complete and a state where the same circuit path 414S is incomplete. However, consistent with the scope and spirit, it may be possible to employ mechanically modifiable ele-

In an alternative embodiment, a strip 412 or other mechani- 60

cally modifiable element 412 may have a surface coating of a removable material, such as it is sometimes found on lottery tickets and similar items. The user may then mechanically modifYing the strip 412 by scratching off the surface material. The strip 412 may be configured so that scratching off the surface material modifies an electrical state of the strip 412, resulting in a detectable change of configuration.

65 ments which have more than two circuit states, or which even have continuous states associated with them. For example, it may be possible to develop or employ the invention using


US 7,876,222 B2 23

mechanically modifiable elements 412 which provide analog values of a resistance, a capacitance, an inductance, or a combination of impedances.

The invention has been described above in conjunction with embodiments where the principle data reported by RFID tag 402 may be only the identification of the RFID tag 402 and the status of the mechanically modifiable elements 412. However, it is possible to attach any number of sensors or to associate a variety of sensors with an RFID tag 402. For example, temperature sensors, pressure sensors and other 10

types of sensors have been employed in conjunction with RFID tags 402. Consistent with the scope and spirit of the invention, it may be further possible to attach a variety of sensors to the RFID tag 402, and to program or modify the behavior of those sensors, the data reported via those sensors, 15

or a response to those sensors, by using the mechanically modifiable elements 412 as described above.

The invention has been described above with respect to embodiments where the mechanically modifiable elements 412 may be field-labeled, that is, imprinted by the user with an 20

indicia 1104, 1302 in a variety of ways. In an alternative embodiment, the indicia which may be applied either to the mechanically modifiable elements 412 or to the substrate 302 of RFID tag 402, may be of a type of indicia which can be modified so that the tag may be reused for different purposes 25

over time. For example, a text-receiving surface 1606 of a mechanically modifiable element 412, such as a strip 412, may be such that any text imprinted on the surface may be erasable; or it may be the case that a label1602 applied to a label-receiving surface 1604 can be removed and a different 30

label1602 applied at a different time. In embodiments described above, the user modifies a state

of tag 402 by mechanically modifYing a mechanically modifiable element 412. In alternative embodiments, RFID tag 402 may have one or more elements which are not themselves 35

mechanically modified, but where a state of the element may be modified through a mechanical action or other action of a user.

For example, in an alternative embodiment of the invention, a strip or strips 412 may have a chemically reactive 40

substance on the surface or embedded within the strip. The application by a user or by an external system of a second chemical to strip or strips 412 may result in a chemical modification of the strip, thereby changing the state of strip 412 and the electrical conductivity of strip 412. 45

24 fiable element 412 renders RFID tag 402 unresponsive to a query from an RFID reader. In an alternative embodiment, RFID tag may be configured so that mechanically modifying a mechanically modifiable element 412 renders RFID tag 402 responsive to a query from an RFID reader.

11. CONCLUSION

The above examples of a system and method for customizable, mechanically progrannnable RFID tags are exemplary only. Persons skilled in the relevant arts will recognize that a variety of alternatives may exist in terms of materials, relations of structural and operational elements, and methods of employing or applying the same. Such variations fall within the scope and spirit of the invention which is not limited by the particular examples described above.

While various embodiments of the invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the breadth and scope of the invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

What is claimed is: 1. A mechanically modifiable radio frequency identifica

tion (RFID) tag, comprising: a substrate; an integrated circuit (IC) mounted on or within the sub-

strate; a register having a plurality of bits; a plurality of strips coupled to said substrate and associated

with at least one bit of said register, the strip having a surface constructed and arranged to receive a visual or tactile indicia;

an adhesive coupled with a first side of the strips for attaching one or more of the strips to an item;

an adhesive substance to hold a second side of the strips against the substrate; and

wherein a mechanical modification of a strip alters a value of its associated register bit.

2. The RFID tag of claim 1, wherein the strip may be customized via said visual or tactile indicia to indicate a significance of said strip for a custom application of said RFID tag.

In an alternative embodiment, one or more strips 412 may have a photosensitive material on the surface. By bringing photo emitting elements into proximity with photosensitive strip 412, for example, by bringing a laser light of a specified color within the proximity of the strip, it may be possible to change the state of the strip in a way which can be detected by the electrical-change detecting circuitry within the RFID tag 412.

3. The RFID tag of claim 1, wherein the strip constructed 50 and arranged to receive a label.

Persons skilled in the relevant parts will recognize that strips 412 ofRFID tag 402 may be configured to be sensitive to other environmental influences which may be mechanically brought into proximity with a strip or strips 412. For example, a strip 412 may be configured to be sensitive to the presence of radioactive materials. Or, for another example, a strip 412 may be configured to be sensitive to the presence of a nearby magnetic field. In either case, a user or a system may bring into proximity with strip 412 a radioactive material or a magnetically active source, thereby changing the state of the strip in a manner which is detectable by circuitry ofRFID tag 402.

In an alternative embodiment, RFID tag 402 may be configured so that mechanically modifYing a mechanically modi-

55

4. The RFID tag of claim 1, wherein the strip is constructed and arranged to receive print.

5. The RFID tag of claim 1, wherein the strip is constructed and arranged to receive a tactile element.

6. The RFID tag of claim 1, wherein the strip is constructed and arranged to receive a user-applied indicia.

7. The RFID tag of claim 1, wherein the strip is a tearable strip constructed and arranged such that severing of the tear-

60 able strip alters the value of its respective register bit.

65

8. The RFID tag of claim 7, wherein: the strip is perforated to facilitate tearing; and severing along a perforation breaks a conductor of the strip,

thereby changing the value of its respective bit. 9. The RFID tag of claim 1, wherein the strip is a punchable

strip constructed and arranged such that punching of the strip alters the value of its respective bit.


US 7,876,222 B2 25

10. The RFID tag of claim 9, wherein the punching of the punchable strip breaks a conductor of the punchable strip, thereby changing the value of its respective bit.

11. The RFID tag of claim 1, further comprising an adhesive coupled to the substrate of the RFID tag for attaching the tag to an item.

26 default value associated with a mechanically unmodified state of said respective strip; and

a control element; wherein: each strip is constructed and arranged so that a mechanical

modification thereof alters a value of its respective bit from the default value to a value different from the default value; and the control element is constructed and arranged to

12. The RFID tag of claim 1, further comprising a control element constructed and arranged to change a default value of said bit from a first default value to a second default value different from the first default value. 10 receive a command to perform at least one of:

modifYing the default value of the bit to a modified default value which is different from an initial default value; or

decoupling said bit from said respective coupled strip

13. The RFID tag of claim 1 further comprising a strip not associated with a register bit, the status of which is intended to provide only a visual indication of a status of a process.

14. The RFID tag of claim 1 including a plurality of strips associated with respective bits of the register.

15. The RFID tag of claim 1, further comprising: a piece of protective material removable removably cover

ing the adhesive on the first side of the strips.

15 and freezing the value of the bit so that said bit decoupled from said strip does not change value in response to the mechanical alteration of the respective strip formerly coupled with the bit.

22. The RFID tag of claim 21, wherein said control element 16. A mechanically modifiable radio frequency identification (RFID) tag, comprising:

a substrate; an integrated circuit (IC) mounted on or within the sub-

strate;

20 is constructed and arranged to be programmable via a radio frequency (RF) signal with an address of a bit of the plurality ofbits and at least one of the modified default value of said bit or an indication to fix decoupled the bit from said respective

a register having a plurality of bits; and a strip coupled to said substrate and associated with at least 25

one bit of said register, the strip having a surface constructed and arranged to receive a visual or tactile indiCia;

wherein a mechanical modification of a strip alters a value of its associated register bit; and

wherein the IC is constructed and arranged to detect at least one of: a pattern of the bits in the register; and a time order in which the pattern of bits in the register changes.

17. The RFID tag of claim 16, wherein the tag is constructed and arranged to transmit the bit pattern of the register.

18. The RFID tag of claim 16, wherein the tag is constructed and arranged to transmit the time order in which the pattern of bits in the register changes.

19. The RFID tag of claim 16, wherein the RFID tag is constructed and arranged to transmit an alert signal in response to the detection of a specific pattern or a specific time order.

30

35

40

20. A mechanically modifiable radio frequency identifica- 45

tion (RFID) tag, comprising: a substrate; an integrated circuit (IC) mounted on or within the sub-

strip and to the value of said bit. 23. The RFID tag of claim 21, further comprising a control

strip constructed and arranged so that mechanically modifYing the control strip triggers the control element to at least one of modify said default value of said bit or decoupled the bit and freeze said value of said bit.

24. The RFID tag of claim 21, wherein a least one strip has a surface constructed and arranged to receive a visual or tactile indicia.

25. The RFID tag of claim 21, wherein said strip comprises at least one of:

a tearable strip, wherein the mechanical modification comprises severing the strip; and

a punchable strip, wherein the mechanical modification comprises punching the strip.

26. The RFID tag of claim 21, wherein: the strip further comprises a continuous conductor coupled

to the respective bit associated with the strip; and the conductor is breached by at least one of severing the

strip or punching the strip. 27. The RFID tag of claim 21, wherein the IC is constructed

and arranged to detect at least one of: a pattern of the bits in the register; and a time order in which the pattern of bits in the register

changes. strate;

a register having a plurality of bits; and 50 28. The RFID tag of claim 27, wherein the tag is con-

structed and arranged to transmit at least one of: the bit pattern of the register;

a strip coupled to said substrate and associated with at least one bit of said register, the strip having a surface constructed and arranged to receive a visual or tactile indi-c1a;

wherein a mechanical modification of a strip alters a value of 55

its associated register bit; and a control element constructed and arranged to control the value of a bit of said register regardless of the status of an associated strip.

21. A mechanically modifiable radio frequency identifica- 60

tion (RFID) tag, comprising: a substrate; an integrated circuit (IC) mounted on or within the sub

strate; a plurality of strips coupled to said substrate; a register having a plurality of bits, each bit being associ

ated with a respective strip, each bit configured to have a

65

the time order in which the pattern of bits changes; an alert in response to a specific bit pattern; or an alert in response to a specific time order in which the

pattern of bits changes. 29. The RFID tag of claim 21, further comprising at least

one of an adhesive element of the RFID tag and an adhesive element of the strip.

30. A method for monitoring an item or a process using a radio frequency identification (RFID) tag, wherein the RFID tag comprises:

a substrate; a register have a plurality of bits; a plurality of strips, each strip being associated with a

respective bit, and each strip being suitable to receive a visual or tactile indicia of a purpose of the strip;


US 7,876,222 B2 27

an adhesive coupled with a first side of the strips for attaching one or more of the strips to an item;

an adhesive substance to hold a second side of the strips against the substrate;

the RFID tag being constructed and arranged such that a modification of a strip changes a value of the strip's respective register bit;

comprising: (a) assigning the RFID tag to at least one of the item, the process, an item associated with the process, a person monitoring the process, a monitoring device associated with the process, an assembly line associated with the process, a monitaring station associated with the process, and a conveyance associated with the process;

28 process, an assembly line associated with the process, a monitaring station associated with the process, and a conveyance associated with the process; (b) associating a strip of the plurality of strips with a respective process step or a respective item status; (c) upon performance of a step of the process or a change of the item status, mechanically modifying the strip associated with that step or status; (d) reading the RFID tag to determine a bit pattern of the

10 register of the RFID tag; and (e) detecting at least one of a particular pattern of bits in the register or a particular order in which the strips are modified.

37. A method for monitoring an item or a process using a radio frequency identification (RFID) tag, wherein the RFID

(b) associating a strip of the plurality of strips with a respec- 15 tag comprises: a substrate; tive process step or a respective item status;

(c) upon performance of a step of the process or a change of the item status, mechanically modifying the strip associated with that step or status; and

a register have a plurality of bits; a plurality of strips, at least one strip being selectively

associated with a respective register bit; (d) reading the RFID tag to determine a bit pattern of the 20

register of the RFID tag. an adhesive coupled with a first side of the strips for attach

ing one or more of the strips to an item;

31. The method of claim 30, further comprising: configuring the strip of the RFID tag to be automatically

modified upon the performance of the step or change of status associated with the strip.

32. The method of claim 30, further comprising at least one of modifYing a default value associated with a bit or an ability of a bit to change value in response to a mechanical modification of the strip associated with the bit.

33. The method of claim 32, further comprising: (i) accepting via a radio frequency (RF) link of the RFID

tag an identification of a bit of the plurality of bits;

25

an adhesive substance to hold a second side of the strips against the substrate;

the RFID tag being constructed and arranged such that a modification of a strip changes a value of its associated register bit;

comprising: (a) assigning the RFID tag to at least one of the item, the process, an item associated with the process, a person moni-

30 taring the process, a monitoring device associated with the process, an assembly line associated with the process, a monitaring station associated with the process, and a conveyance associated with the process; (ii) accepting via the RF link an indication of whether a

default state of the bit is to be changed or whether the value of the bit is to be rendered unchangeable; and 35

(b) associating a strip with a respective process step or a respective item status; (c) modifYing at least one of 1) a default value associated with a bit or 2) the association of a bit with a strip thereby controlling the ability of the bit to change value in response to a mechanical modification of a strip associated with the bit;

(iii) responsive to the data accepted via steps (i) and (ii), assigning to the identified bit a new default state which is different from the current default state of the identified bit or rendering the value of the identified bit as unchangeable.

34. The method of claim 33, wherein step (iii) further comprises:

40 (d) upon performance of a step of the process or a change of the item status, mechanically modifying the strip associated with that step or status; and

(iv) storing in a memory of the RFID tag the identification of the identified bit from step 34(i) and the indication

45 from step 34(ii);

(e) reading the RFID tag to determine a bit pattern of the register of the RFID tag.

38. The method of claim 37, further comprising: configuring the strip of the RFID tag to be automatically

modified upon the performance of the step or change of status associated with the strip.

(v) upon detecting a mechanical modification of a control strip of the RFID tag, assigning to the identified bit the new default state or rendering the value of the identified bit as unchangeable.

35. The method of claim 30, further comprising labeling each strip to signify at least one of the process step associated with the strip or the item status associated with the strip.

39. The method of claim 37, further comprising labeling 50 each strip to signifY at least one of a process step associated

with the strip or an item status associated with the strip.

36. A method for monitoring an item or a process using a radio frequency identification (RFID) tag, wherein the RFID 55 tag comprises:

a register have a plurality of bits; a plurality of strips, each strip being associated with a

respective bit, and each strip being suitable to receive a visual or tactile indicia of a purpose of the strip;

the RFID tag being constructed and arranged such that a modification of a strip changes a value of the strip's respective register bit;

comprising:

60

(a) assigning the RFID tag to at least one of the item, the 65

process, an item associated with the process, a person monitoring the process, a monitoring device associated with the

40. The method of claim 37, wherein step (c) further comprises:

(i) accepting via a radio frequency (RF) link of the RFID tag an identification of a bit of the plurality of bits;

(ii) accepting via the RF link an indication of whether a default state of the bit is to be changedorwhetherthe bit is to be associated or disassociated with a strip; and

(iii) responsive to the data accepted via steps (i) and (ii), assigning to the identified bit a new default state which is different from the default state of the identified bit or disassociating the bit with a strip.

41. The method of claim 40, wherein step (iii) further comprises:

(iv) storing in a memory of the RFID tag the identification of the identified bit from step 41 (i) and the indication from step 41(ii);


US 7,876,222 B2 29

(v) upon detecting a mechanical modification of a control strip of the RFID tag, assigning to the identified bit the new default state or decoupling the bit.

42. A method for monitoring an item or a process using a radio frequency identification (RFID) tag, wherein the RFID tag comprises:

a register have a plurality of bits;

a plurality of strips, at least one strip being selectively associated with a respective register bit;

the RFID tag being constructed and arranged such that a modification of a strip changes a value of its associated register bit;

comprising:

(a) assigning the RFID tag to at least one of the item, the process, an item associated with the process, a person monitoring the process, a monitoring device associated with the

30 process, an assembly line associated with the process, a monitaring station associated with the process, and a conveyance associated with the process; (b) associating a strip with a respective process step or a respective item status; (c) modifYing at least one of 1) a default value associated with a bit or 2) the association of a bit with a strip thereby controlling the ability of the bit to change value in response to a mechanical modification of a strip associated with the bit;

10 (d) upon performance of a step of the process or a change of the item status, mechanically modifying the strip associated with that step or status; (e) reading the RFID tag to determine a bit pattern of the register of the RFID tag; and

15 (f) detecting at least one of a particular pattern of bits in the register or a particular order in which the strips are modified.

* * * * *


PATENT NO. APPLICATION NO. DATED INVENTOR(S)

UNITED STATES PATENT AND TRADEMARK OFFICE

CERTIFICATE OF CORRECTION

: 7,876,222 B2 : 11/847974 : January 25, 2011 : Ca1varese

Page 1 of 1

It is certified that error appears in the above-identified patent and that said Letters Patent is hereby corrected as shown below:

On the Face Page, in Field (57), under "ABSTRACT", in Column 2, Line 9, delete "or the process." and insert-- of the process. --,therefor.

In Column 1, Line 31, delete "tags" and insert -- tags. --, therefor.

In Column 11, Line 67, delete "tearing." and insert-- tearing,--, therefor.

In Column 15, Line 10, delete "to the," and insert --to the --, therefor.

In Column 19, Line 52, delete "tom," and insert-- tom, --,therefor.

In Column 21, Line 2, delete "spirit of the." and insert-- spirit of the invention. --,therefor.

In Column 26, Line 30, in Claim 24, delete "a" and insert -- at--, therefor.

Signed and Sealed this First Day of January, 2013

~JJ:•·t::~ David J. Kappos

Director of the United States Patent and Trademark Office


111111 1111111111111111111111111111111111111111111111111111111111111111111111111111 US 20070152157Al

(19) United States c12) Patent Application Publication

Page (10) Pub. No.: US 2007/0152157 A1 (43) Pub. Date: Jul. 5, 2007

(54) SIMULATION ARENA ENTITY TRACKING SYSTEM

(75) Inventor: David Wayne Page, Cocoa, FL (US)

Correspondence Address: STERNE, KESSLER, GOLDSTEIN & FOX P.L.L.C. 1100 NEW YORK AVENUE, N.W. WASHINGTON, DC 20005 (US)

(73) Assignee: Raydon Corporation, Daytona Beach, FL (US)

(21) Appl. No.:

(22) Filed:

111593,066

Nov. 6, 2006

Related U.S. Application Data

(60) Provisional application No. 60/733,254, filed on Nov. 4, 2005.

DAE

..... '··P.a

1

Publication Classification

(51) Int. Cl. GOJJ 5102 (2006.01)

(52) U.S. Cl. .............................................................. 250/340

(57) ABSTRACT

A system and method employing visual tracking devices to locate simulation players and objects within an enclosed space. These visual tracking devices capture a perspective view of the arena and analyze the image at a fixed perception frame rate. Each player and object to be tracked is identified by a light-emitting device called a tracking point source, which is identified in the environment by means of a unique code sent out by the device and received by the visual tracking device. By using multiple tracking point sources, the invention may not only determine positions but also determine the orientation (relationship) between players and objects. A third component in the invention performs frameto-frame analysis of all visible point sources to determine motion in three dimensions, which is forwarded to the simulation environment where it is used to enmesh the player in the simulation.

/

..Pb

-·· -··


Patent Application Publication Jul. 5, 2007 Sheet 1 of 9 US 2007/0152157 A1

I 110a .....

'··P.a

Simulation Arena

, . "':l TPS "- ~ - · · - .. - .. - ..

120~~-····································x········································ I 105

. l'iJ ·············-k l1 05

105 ········· .. J

FIG. 1A

DAE 1); •-"

....

1

FIG. 18



200 210

205 Load TPS Identification Initialize VTD array.

Data Into System. I ..

220 Modulate energy emission of TPS

which is attached to object

i_ 225 Monitor TPS using VTDs

+ VTD delivers to DAE location-related

data for the TPS 230

~ 270 DAE identifies an

DAE re-identifies TPS on successive video

frames using tracking sorting algorithms, and ... I apparently new

TPS previously identified path and motion data I

235

• + DAE generates per-point location-data history I

·-table I

+ + 240

DAE correlates location-related data from I

multiple VTDs to determine the 3-d position I -·-1 245

(i.e., the location) of the TPS I Data

+ I feedback

DAE identifies TPS as·a particular, unique + 237

250 TPS based on unique energy modulation -·"i pattern I

+ + DAE analyses time-series of positions for the I

255 unique TPS to determine path of motion of 1-·""f

TPS and equation of motions of TPS I

+ t DAE extrapolates likely new position for TPS I

260 based on previously determined TPS position,

path, and/or equation of motion

1-·_J

I '-

+ DAE determines if apparently new TPS is:

275 (i) Actually new, and assigns it a new (previously loaded)

identity, or ~ (ii) A previously identifi~d TPS, blocked from view and now

reaquired.

FIG. 2



c Q)

....J

-c Q)

....J

N c Q)

....J

320

330

110b

FIG. 3

310a

········ ... ····--.... 120

············,(~ Len3

Len3 = tan(Y 2)*Len/tan(y1)

X Ordinal



420 410

320 ~ I 1\

P-I~ _!._ I'

-~ -FIG. 4A

Intensity = ixy

FIG. 48



110a 110b

520

FIG. 5


600

605

Current Instance

Point Source

List

Current Point Track

Equation List

610

615

List t-

620

Radial Distance

~ Computation

625

__., ..

Radial .. , Bubble Distance J Sort

r-"-1 Computation Closest

.. Radial Distance

r----1 Computation .....-.-:TTTllTJTlrraTliOn

Match

1 ..,1 Extrapolated I-

to Current Velocity Window 1622

Sizer Instance

FIG. 6

605'

Revised Instance

Point Source

List

Revised Point Track

Equation List

610'

'"= ~ ..... ('D

= .....

~ "e -.... (')

~ ..... .... 0

= '"= = 0" -.... (')

~ ..... .... 0

= 2' :-~Ul

N 0 0 -....l

rFJ

=('D ('D ..... 0\

0 -. 'C

c rFJ N 0 0 ~ 0 .... Ul N .... Ul -....l

> ....



Perception Frames 702

1 2 3 4 5 6 7 6

~~~~~~t~~~Ji~:~l ~I ~I ~ 111 ~I ~I 61 ~I Bits :

I \...._ ____ ....,

v One byte modulation pattern -

Each bit is part of the. pattern. 730a

Time

FIG. 7A

14 15 16

Perception frame I energy emission event pair 705


1 2 3 4 5 6 7 6 9 10 11 12 13 14 15 16

I I I

BitNumber710b0

j ~I~~~~~~~~~~~~~~~~~~~~~ ~161 ~~ ~~ ~~

Modulationy_/ V l//)j 720b One byte modulation pattern -- Beacon Bits 725b

Alternate bits are modulation bits Alternate bits are beacon bits

Time

FIG. 78




Distinct signal frames 820 Ambiguous signal frames 825

pn Modulation Bit 810 1

Off Modulation Bit 815:

Energy emission events 703

-~------~ r-------~~~------~ r-------~~--------~ ~-------J~ v v v TPS modulation pattern 730d -- TPS modulation pattern 730e -- TPS modulation pattern 730f --

Repetition 1 Repetition 2 Repetition 3

Recieved: 10110101 - ok


Recieved: 111101 01 - error

Recieved: 11111111 - error


y \. )

Time

FIG. SA


0 2 3 4 5 6 7 I I I I

11 OI1-I1IOI1IOI11

111 OI111IOI1IOI11

8

111 OI111IOI1IOI11

111 OI111IOI1IOI11

<t1] o I 1 (]:Do I 1 I o I I Energy emission events

703

9 10 I I

TPS Modulation Pattern from a single TPS, repeated 5 successive times. 855

Received TPS modulation patterns as interpreted by VTD or DAE on five successive occasions 860

Within a single modulation pattern, horizontal axis is time . .., Between modulation patterns, horizontal axis is phase shift.

FIG. 88


Patent Application Publication Jul. 5, 2007 Sheet 9 of 9

0 v ......

......

......

0 0 ......

co 0 ......

\

/

\

0 0 0>

/ c .... :m co

Q_

US 2007/0152157 A1

0 N I'-


US 2007/0152157 AI

SIMULATION ARENA ENTITY TRACKING SYSTEM

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Application No. 60/733,254, filed on Nov. 4, 2005.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] This invention relates to tracking the position and motion of one or more entities in a three-dimensional space as part of a training or simulation environment.

[0004] 2. Background Art

[0005] As understood in this document, a simulation is a physical space in which real people and/or real objects may move, change location, possibly interact with each other, and possibly interact with simulated people and/or simulated objects (whose presence may be enacted via visual projections, audio emissions, or other means) typically in order to train for, prepare for, experience, analyze, or study real-life, potentially real-life, historical, or hypothetical situations, activities, or events. Simulations may be conducted for other purposes as well, such as educational or entertainment purposes, or for analyzing and refining the design and performance of mechanical technologies (such as cars or other transportation vehicles, weapons systems, etc.). The simulation as a whole may also be understood to include any technology which may be necessary to implement the simulation environment or simulation experience.

[0006] A simulation may be conducted in an environment known as a simulation arena (or simply as an arena, for short). Realistic simulations of events play a key role in many fields of human endeavor, from the training of police, rescue, military, and emergency personnel; to the development of improved field technologies for use by such personnel;

[0007] to the analysis of human movement and behavior in such fields as athletics and safety research. Increasingly, modem simulation environments embody simulation arenas which strive for a dynamic, adaptive realism, meaning that the simulation environment can both provide feedback to players in the environment, and can further modifY the course of the simulation itself in response to events within the simulation environment. It may also be desirable to collect the maximum possible amount of data about events which occur within the simulation environment.

[0008] For a simulation to be maximally dynamic and adaptive, the technology (which may be a combination of hardware and software) controlling the simulation arena requires information on activity within the simulation environment. An essential component of this information is data on the location and movement of entities-people and objects-within the simulation environment.

[0009] Further, the more specific the location and movement data which may be obtained, the more detailed and refined can be the simulation response. For example, it is desirable to obtain information not only on where a person might be located, but even more specific information on where the person's hands, head, or feet might be at a given

1 Jul. 5, 2007

instant. A location granularity on the order of feet or meters is highly desirable, and even more fine-grained location discrimination (such as on the order of inches or centimeters) is desirable as well. It is further desirable to be able to determine the orientation in space of people and objects, as well as their rotational motion.

[0010] A further goal of simulation environment monitoring is to be able to distinguish between specific entities within the simulation environment, so that each real person and each real object has a unique identity within the environment, and so that the location, movement, and simulation history of each real person and real object may be tracked effectively. Yet a further goal is to provide person/object location tracking in real-time, so that adaptive responses may be provided in real-time as well.

[0011] However, obtaining detailed information on the location and movement of entities in a simulation environment offers significant technical challenges. One possible means of tracking is to simply monitor the environment via a video camera or multiple video cameras, and use computer-based analysis to track the movements of people and objects. However, a typical simulation may involve dozens or possibly hundreds, even thousands of real people and real objects, all of which must be tracked. The real-time automated analysis of complex visual data is an art-form still in its infancy; achieving a detailed delineation and tracking of the location and movement of dozens or hundreds of entities using only computer analysis of video images may not be cost-effective in terms of the amount of computing power required, Moreover, using this technology to achieve acceptable entity-identification reliability, acceptable location-determination reliability, real-time processing, or a combination of the above, may be difficult as well.

[0012] A means to achieve the desired goal is to physically attach, to the simulation participants (i.e., to the real persons and real objects within the simulation arena), some kind of signal emitting or signal receiving technology which can assist in the identification and location monitoring of the participants. (Simulation participants may also be known as "entities".)

[0013] As one example of this approach, a global positioning system (GPS) monitor may be attached to simulation participants, enabling a determination of their location via the GPS system. However, GPS monitors may be bulky and expensive, and also may not provide the desired degree of location resolution. Another approach may be to attach radio-frequency (RF) emitters to the simulation participants, wherein nearby RF monitoring devices may detect the RF emissions and so do location determinations. However, due to the long wavelengths of RF emissions, and also due to other factors related to RF behavior in small, object-filled environments, obtaining location data by this means may not be reliable either. Similarly, other means of entity location determination, such as audio signaling, pose significant technical challenges as well.

[0014] Given the foregoing, what is needed is a method and system for determining the position of entities in a simulation environment, wherein the position and movement of each unique entity can be uniquely tracked. What is further needed is a method and system for accomplishing this goal which provides a high degree of both spatial and time resolution, so that detailed location and movement


US 2007/0152157 AI

tracking of each entity may be accomplished. What is further needed is a method and system of entity location determination and entity movement tracking in a simulation environment which is cost-effective, and which is unobtrusive in terms of its impact on entities within the simulation environment.

SUMMARY OF THE INVENTION

[0015] This invention uses energy-emitting tracking point sources (TPSs) to identify the location and motion of entities (persons and objects) within a simulation environment, where the TPSs typically emit light in the infrared ranges. By modulating the TPSs in a distinguishing manner, each TPS may be uniquely identified. The TPSs are viewed by each of a plurality of visual tracking devices (VTDs), wherein the VTDs record activity in a sequential series of short periodic time intervals known as perception frames. By correlating location-related data from multiple VTDs, it is possible to determine the three-dimensional location of the uniquely identified TPSs. Further processing then determines a path and an equation of motion of each TPS.

[0016] By performing this process using hundreds of TPSs, the motion and orientation of entities in an arena may be discerned for each perception frame. The motion and orientation of each TPS in an arena may then be used for any of a variety of purposes including, for example and without limitation, updating head mounted display views, determining weapon aim-points, or determining locations of physical obstacles in a virtual world. This system may also be employed, for example, for tracking objects or players in sports events, analyzing dance choreography, and facilitating analysis of other multi-body three-dimensional motion problems.


[0017] The features and advantages of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings in which like reference numbers indicate identical or functionally similar elements.

[0018] Additionally, the left-most digit of a reference number identifies the drawing in which the reference number first appears (e.g., a reference number '310' indicates that the element so numbered first appears in FIG. 3). Additionally, elements which have the same reference number, followed by a different letter of the alphabet or other distinctive marking (e.g., an apostrophe), indicate elements which are the same in structure, operation, or form but may be identified as being in different locations in space or recurring at different points in time (e.g., reference numbers '110a' and '110b' may indicate two different energy detection devices which are functionally the same, but are located at different points in a simulation arena).

[0019] FIG. 1A and FIG. 1B illustrate an arena where a simulation event takes place, and where energy-emitting tracking point sources (TPSs) attached to entities (people or objects) are used to monitor entity motion in the arena.

[0020] FIG. 2 is a flow chart showing the overall process of determining the identity, location and movement of an entity in an arena according to one embodiment of the present invention.

2 Jul. 5, 2007

[0021] FIG. 3 illustrates a method for the computation of the location of a TPS in the arena, where the TPS is in the field of view of a visual tracking device (VTD) which is mounted in the arena to monitor TPSs, according to one embodiment of the present invention.

[0022] FIG. 4A and FIG. 4B together illustrate a method for locating a TPS in a VTD field of view, and hence for identifying an angle of incidence of a ray of light from a TPS relative to the backplane of the VTD, according to one embodiment of the present invention.

[0023] FIG. 5 illustrates how two VTDs together may determine a substantially localized region in space in which a TPS may be located, according to one embodiment of the present invention.

[0024] FIG. 6 illustrates a process for tracking the location of a moving TPS over time, according to one embodiment of the present invention.

[0025] FIG. 7A and FIG. 7B illustrate two different embodiments of a synchronous energy modulation scheme which may be used to uniquely identifY a TPS.

[0026] FIG. SA and SB illustrate two different embodiments of an isochronous energy modulation scheme which may be used to uniquely identifY a TPS.

[0027] FIG. 9 illustrates how various aspects of the present invention, such as location identification, path tracking, and object identification, may work in combination with each other in one possible embodiment of the invention.

[0028] Further embodiments, features, and advantages of the present invention, as well as the operation of the various embodiments of the present invention, are described below with reference to the accompanying figures.

DETAILED DESCRIPTION OF THE INVENTION

[0029] An embodiment of the present invention is now described with reference to the figures. While specific configurations and arrangements are discussed, it should be understood that this is done for illustrative purposes only. A person skilled in the relevant art(s) will recognize that other configurations and arrangements can be used without departing from the spirit and scope of the invention. It will be apparent to a person skilled in the relevant art that this invention can also be employed in a variety of other systems and applications.

Overview

[0030] FIG. 1A and FIG. 1B illustrate an arena 100, which is defined as a bounded region of space which may be either indoors or outdoors, with a plurality energy detection devices 110 which may be video cameras or other visual monitoring devices 110. These visual monitoring devices 110 are mounted in such a way that each one of the visual monitoring devices 110 has a field of view which at least partially overlaps with the field of view of at least one other of the plurality of visual monitoring devices 110. These visual monitoring devices 110 are referred to, in the present context, as visual tracking devices 110 (VTDs ), and may be mounted in the periphery, or the interior, or both the periphery and interior, of a bounded volume of space to be monitored. FIG. 1 illustrates an exemplary embodiment


US 2007/0152157 AI

only, in which only three VTDs 110 are in use, but this is for purposes of illustration only. More VTDs 110 may be used, and the locations of the VTDs are not limited to the upper comers of an arena.

[0031] The terms or acronyms "energy detection device", "visual monitoring device", "visual tracking device", "VTD", and the plurals thereof, will be used interchangeably and synonymously throughout this document. It should be understood that an energy detection device, visual monitoring device, visual tracking device, or VTD 110 may encompass at least the capabilities for obtaining a time-series of images as typically embodied by a standard video camera. However, it should be further understood that an energy detection device, visual monitoring device, visual tracking device, or VTD 110 may embody other capabilities or modified capabilities as well. These capabilities may include, for example and without limitation, the ability to obtain image data based on energy in the infrared spectrum or other spectral ranges outside of the range of visible light; the ability to modify or enhance raw captured image data; the ability to perform calculations or analyses based on captured image data; the ability to share image data or other data with other technologies over a network or via other means; or the ability to emit or receive synchronization signals for purposes of synchronizing image recording, data processing, and/or data transmission with external events, activities, or technologies.

[0032] Other enhanced capabilities, adaptations, or modifications of an energy detection device, visual monitoring device, visual tracking device, or VTD 110 as compared with a standard video camera may be described further below in conjunction with various embodiments of the present invention.

[0033] The arena 100 is generally understood as the bounded volume of space wherein a simulation or gaming event may be conducted, wherein the boundaries may be defined by walls or other delimiters or markers, and wherein substantially all or most of the bounded volume of space will be monitored by the plurality of VTDs 110. However, the arena 100 may also be understood to be defined topologically as the set of all points which are visible to two or more VTDs 110, since at least two VTDs 110 may be needed to identify the location of an entity 130 in the arena.

[0034] An arena 100 may be created for the purposes of establishing an environment for human training or human event simulation, or for the testing of technologies which may be directly human controlled, remote controlled, or entirely automated, or for other purposes. FIG. 1A also shows how a coordinate system 105 may be imposed upon the arena 100 for the purpose of identifying the location of TPSs 120 within the arena. A conventional Cartesian X-Y-Z coordinate system 105 is illustrated, but other coordinate systems may be used including, for example and without limitation, a spherical coordinate system or a cylindrical coordinate system.

[0035] As shown in FIG. 1B, in operational use an arena 100 will contain at least one entity 130, such as a person or object 130, and possibly multiple persons or objects 130, wherein it is expected that the person or object 130 will be in motion within the space of the arena 100 at some point in time. FIG. 1B shows a person 130, sometimes referred to in the art as a "player", who may be in motion. For simplicity,

3 Jul. 5, 2007

the remainder of this document typically refers simply to an entity 130 or entities 130, it being understood this term refer may refer to persons, animals, plants, inanimate objects, or any kind of entity 130 which may be in motion within the arena 100. The terms "person", "object", "device", or "player" or the plurals thereof may be employed as well, and will be understood to be interchangeable with "entity" or "entities".

[0036] Attached to an entity 130 may be at least one tracking point source (TPS) 120. Shown in FIG. 1A and FIG. 1B are four TPSs 120; the three TPSs 120a, 120b, and 120c in FIG. 1B are attached to the figure of the person 130 (and may not be drawn exactly to scale in relation to the person); the TPS 120 of FIG. 1A is shown unattached to any entity, which may not typically be the case in the normal course of operations of the invention. However, in an embodiment of the present invention a stationary TPS 120 or stationary TPSs 120 may be attached to walls or boundaries, or placed at other fixed locations in the arena 100 or near the arena 100 for a variety of purposes including, for example and without limitation, boundary delineation, VTD 110 perception frame synchronization (perception frames and synchronization are discussed further below), VTD 110 error checking or VTD 110 calibration, as a further means for or supplement to other means for distance determinations or angular determinations, or for other purposes.

[0037] It should be further understood that while not every entity 130 in the arena may have a TPS 120 attached, any entity 130 whose motion is of interest may have at least one TPS 120 attached to it. Attaching more than one TPS 120 to an entity 130 may allow for detection of entity 130 orientation or angular motion.

[0038] A TPS 120 is a source of energy emission, which may be an energy emitting device which is physically small compared to the physical size of the entity 130. The terms or acronyms "source of energy emission", "tracking point source", "TPS", and the plurals thereof are used interchangeably and synonymously in this document.

[0039] The actual energy-emitting component itself, which may be only one component of the source of energy emission 120, may be small enough to be considered as substantially a point source of light. The energy emitted by the TPS 120 may be infrared light, or possibly light in some other frequency range. The light emitted by the TPS 120 may be in the visible light range; however, this poses the possibility of interference caused by normal room lighting unless special steps are taken to prevent this. Therefore, it may be preferred to have the TPS 120 emit light outside the range of light frequencies used to illuminate the arena 100. The light emitted by the TPS 120 falls in a frequency range which can be detected by the VTDs 110. In one embodiment of the present invention, each VTD 110 may be limited to sensing light emissions in an energy range beyond human perception (e.g., 780-960 nm), and hence the light emitted by the TPSs 120 would fall in this range as well.

[0040] A TPS 120 will at a minimum be comprised of an element or component (already referred to above) for emitting electromagnetic energy, a means for powering the electromagnetic energy-emitting component, and a means for modulating the emissions of the electromagnetic energyemitting component. In one embodiment of the present invention, the electromagnetic energy-emitting component


US 2007/0152157 AI

may emit infrared light. In another embodiment of the present invention, the electromagnetic energy-emitting component may emit light in the visible range. For the sake of brevity, in the remainder of this document we may speak of a "light-emitting component", an "infrared emitting element", an "IR emitting element", or similar terms, along with "light emissions" and similar terms; but nothing in this terminology should be understood as limiting the frequency or wavelength of electromagnetic energy which may be emitted by the electromagnetic energy-emitting component.

[0041] Each TPS 120 may internally store its identity, i.e., the unique modulation pattern for its energy emission, and may possess a means for said storage such as an internal memory chip. A TPS 120 may have a hard-coded, fixed modulation pattern, or a TPS 120 may be programmable to upload into the TPS 120 different modulation patterns. In turn, this identity (that is, the unique modulation pattern) may be registered with the system, for example, with a data analysis engine (DAE) 140, prior to the start of operations of a simulation. The DAE 140 is discussed further below.

[0042] The size of the TPSs 120 can be small enough to allow an entity 130 in the arena 100 to be identified by multiple TPSs 120. This may allow a single TPS 120 to be used to identifY position alone, while two TPSs 120 may provide 3-d orientation. A TPS 120 may be implemented using an infrared (IR) emitter and a micro-processor. Alternatively, a TPS 120 may be implemented using an IR emitter and a programmed logic array. A TPS 120 may also be implemented using an IR emitter and a memory cell used to store and replay an identity message (that is, an energy emission modulation pattern, discussed further below) through the IR emitter. A TPS 120 may have other components, as well, such as a means for synchronization with the VTDs 110, also discussed further below.

[0043] In one embodiment of the present invention, each TPS 120 has a single light-emitting component. In an alternative embodiment of the present invention, a single TPS 120 may have two or more light-emitting components, which may be used for such purposes as determining an orientation of the TPS 120, providing a means to obtain light from one light-emitting component when another lightemitting component is temporarily occluded from view of a VTD 110, or for other purposes. If a TPS 120 has more than one light-emitting component, each such component may emit light at the same frequency or may emit light at a different frequency from the others, and each such component may be modulated using the same energy modulation pattern or may be modulated using a different energy modulation pattern from the others.

[0044] TPSs 120 are attached to and physically tag entities 130 to be tracked in the arena 100. A TPS 120 may be attached to the tracked entity 130 using a variety of means of attachment including, for example and without limitation, tape, glue, Velcro™, screws, bolts or gum. A TPS 120 may be permanently integrated into a device 130 for use in an arena 100 tracking environment. TPSs 120 may be enhanced using other location or movement detection technologies including, for example and without limitation, accelerometers, magnetometers, or GPS equipment, which may detect orientation of a device 130 in the arena 100 environment, or which may supplement the location information provided by the method of the present invention.

4 Jul. 5, 2007

[0045] In general, a VTD 110 may use a video-camera based technology to detect the TPSs 120. A VTD 110 may alternatively use a solid-state imager-based technology to detect the TPSs 120. Note that a VTD 110 may be a multi-imager VTD (not shown), having two or more energy sensors separated by some distance, e.g., 10 em. This may provide stereoscopic determination of distance, in addition to perspective angles.

[0046] Alternatively, distance can be determined by triangulation, using two or more physically separate VTDs 110, as discussed further below.

[0047] Collectively, the VTDs 110 in the arena are referred to as the VTD array. In FIG. 1A, multiple VTDs 110 in the VTD array are used to locate a TPS 120 in the arena in each of three dimensions X, Y, and Z. VTDs 110 are arranged so as to give overlapping coverage of the space. The orientation and perspective of each VTD 110 may be designed to provide maximum coverage of the available space, resulting in the largest possible volume of locations where TPSs 120 may be in view of the VTDs 110; or may be designed to ensure the highest probability that a TPS 120 will always be within the field of view of at least two VTDs 110, or possibly more than two VTDs 110, to ensure optimum TPS 120 tracking; or the orientation and perspective of the VTDs 110 may be designed to provide a balance between maximum spatial coverage and maximum likelihood of optimum TPS 120 tracking. Other design considerations may be a factor as well in the placement or orientation ofVTDs 110.

[0048] For reduction of a three-dimensional fix, a minimum of two VTDs 110 perspectives is necessary. Once a fix has been made on the location of a TPS 120, the system builds a three-dimensional path model. Once a path model is established a TPS 120 may be tracked using one or more VTDs 110. These details are discussed further below.

[0049] A final element of the overall invention is a data analysis engine (DAE) 140, which is a computer or analogous computational device or centralized processing unit which integrates and analyzes data from the VTDs 110 in the VTD array to determine the motion of entities 130 within the arena. DAE 140 may be networked to both the VTDs 110 and an arena host computer system (pot shown).

[0050] The DAE 140 may be local to each arena if there are multiple arenas in use, and may perform four main tasks:

[0051] The first task may be matching TPS lists from multiple VTDs into multiple perspective views per TPS. A TPS list may be a VTD-specific list of all TPSs 120 which have been within the field of view of a VTD 110, and which may be found within the field of view of the same VTD 110 in upcoming perception frames. As discussed further below, establishing a TPS list may entail demodulating the modulated light emission from each TPS 120. (Alternatively, demodulation of the TPS identities may be performed at each VTD independent of the DAE 140; this task may be performed by each VTD 110, which may employ onboard processing and memory, and which may also maintain its own TPS list.)

[0052] The second task may be to build 3-dimensional motion formulas for all known TPSs 120 in the system.

[0053] The third task may be to build up lists of unidentified TPSs 120 for future identification. Since TPSs are


US 2007/0152157 AI

occluded in some perspectives or completely occluded for short periods, DAE 140 may determine both a projected solution, i.e., an anticipated position, direction, and equation of motion of known but occluded TPSs 120, as well as a potential best fit for all solutions. These projected locations, directions, and equations of motion may be matched up against the list of unidentified TPSs 120 to determine if an unidentified TPS 120 is, above some threshold of probability or likelihood, a known TPS 120 which has been recaptured by the tracking system.

[0054] A fourth DAE 140 task may be to communicate data concerning entity locations and movement to an arena host computer system (not shown). The arena host computer system may use the data for a variety of purposes including, for example and without limitation, maintaining a history of entity 130 location and movement; reporting on entity 130 location and movement; modifYing, in response to entity 130 location and movement, visual displays or auditory feedback presented to simulation players; or modifying, in response to entity 130 location and movement, elements or aspects of the arena environment, or other aspects of the simulation.

[0055] It may be that most or all of the computational tasks of the present invention are performed by the DAE 140, though some may be offloaded to other elements, such as the VTDs 110 or TPS 120. (For example, identification ofTPSs 120 may be performed by the DAE 140, or may be performed in whole or part by the VTDs 110.) In some embodiments of the present invention, the DAE 140 may perform additional tasks as well.

[0056] FIG. 2 is a flow chart showing the overall process of identifying the movement of an entity according to one embodiment of the present invention. The overall steps are described here in general terms, with more details being provided in later discussion.

[0057] Steps 205 and 210 are initialization steps pertaining to both the TPS modulation and VTD array initialization.

[0058] In one embodiment of the present invention, it is typically expected that more than one TPS 120 will be used, either because more than one entity 130 is being tracked, or because orientation as well as position of an entity 130 is being tracked, or for a combination of these reasons. In order to track the position and motion of more than one TPS 120, it is necessary that the TPSs 120 attached to the entity or entities 130 can be uniquely identified. This is accomplished by having each TPS 120 emit light according to a modulation pattern which is unique among all the TPSs 120 in the system. This modulation pattern is the "identity message" referred to above, and the two terms will be used interchangeably in this document.

[0059] The modulation scheme, in turn, has an implementation which relies on the fact that the VTDs 110 capture motion via successive images called "frames", or "perception frames". The VTDs 110 image (i.e., perform image capture of) the arena scene at a periodic rate called the perception rate. Typical video or solid state imaging technology may capture images at a rate on the order of 15 to 30 frames per second, although a faster or slower perception rate may be used. The inverse of the perception rate may be the length of each perception frame; in one embodiment of the present invention, the VTDs 110 may have a perception

5 Jul. 5, 2007

frame with a duration of 1.!t6th of a second. All VTDs may share the same, constant perception rate and may have perception frames of the same duration.

[0060] The modulation scheme of the present invention works by having a TPS 120 emit light or not emit light (i.e., be modulated on or off, respectively) during a period of time known as an energy emission event. Note that an energy emission event is defined to embody two different types of intervals: an energy emission event may be an interval when the TPS 120 emits light, and an energy emission event may be an interval when the TPS 120 does not emit light. Put another way, an interval when a TPS 120 actually does not emit energy is defined to be one type of energy emission event.

[0061] An energy emission event may have a duration which is substantially close to, though not necessarily the same as, the duration of a single VTD 110 perception frame.

[0062] For example, in one embodiment of the present invention, if a perception frame is 1.!t6th of a second, the duration of an energy emission event, during which a TPS 120 will either emit light or not emit light, will be substantially close to lf16th of a second. The overall modulation pattern of a TPS 120 is expressed over a plurality of energy emission events; a given TPS 120 will present the same modulation pattern repeatedly over successive pluralities of energy emission events. The details of the energy modulation pattern are discussed further below.

[0063] In step 205, TPS identification data is loaded into the system of the present invention. In some cases, this may entail initializing each TPS 120 itself with a modulation pattern. In other instances, the TPSs 120 may already have a modulation pattern built in, or stored from a previous initialization (during a previous simulation run, for example). However, it may still be necessary to program the DAE 140 or otherwise upload data into the DAE 140, so that the DAE 140 knows which modulation scheme is associated with which TPS. In other cases, it may be the case that the DAE 140 is already programmed to know which modulation scheme is associated with which TPS 120. However, it may still be necessary to program the DAE 140 or otherwise upload data into the DAE 140 to indicate which TPS 120 (and hence which modulation scheme) is associated with which entity 130. A DAE 140 may have a TPS database which stores information related to TPS 120 modulation, TPS 120 assignment to entities 130, and other pertinent TPS 120 information.

[0064] In step 210, the VTD 110 initialization is performed. As one aspect of step 210, VTDs 110 may be synchronized. If the VTDs 110 are connected to each other over a network, which may be controlled by the DAE 140, synchronization can be network based, so that all VTDs 110 are synchronized through the network. Alternatively, a synchronization message can be used to initiate and maintain synchronization. Alternatively, a master VTD 110 can modulate a localized VTD 110. In such an embodiment, VTDs 110 follow the lead of the master to determine the start of a perception frame.

[0065] In another aspect of step 210, DAE 140 may be initialized with information about the VTDs 110 in the VTD array. For example, the DAE 140 may contain a database which indicates the location of each VTD 110 in the arena,


US 2007/0152157 AI

and also indicates the orientation of each VTD 110 in the arena. This information may be used by the DAE 140, in conjunction with TPS-related location information provided by the VTDs 110, to determine the location and movement over time of the TPSs 110.

[0066] In step 220, each TPS 120 modulates its energy emission according to the general scheme already described above. That is, a TPS 120 will either emit light or not emit light during an energy emission event, where an energy emission event has a duration in time which may be substantially close to, but is not necessarily the same as, the duration of a perception frame of a VTD 110. Each such energy emission event may also correspond to a single bit in a modulation pattern.

[0067] While the energy emission events have been described above as events of emitting light or not emitting light, in an embodiment of the present invention, the duration of the "on" period or "off' period may be less than the full duration of the energy emission event. An "on" energy emission event may be comprised of the TPS 120 emitting light for more than some threshold period of time, or more than some percentage of time, during the time which may be substantially close to the length of a perception frame. An "off' energy emission event may comprise the TPS 120 emitting light for less than some threshold period of time or less than some percentage of time during the time period which may be substantially close to the length of a perception frame.

[0068] As one example, an "on" energy emission event may be comprised of the TPS 120 emitting light for more than 95% of the indicated duration in time, while an "off' energy emission event may be comprised of the TPS 120 emitting light for less than 5% of the indicated duration in time. As another example, an "on" energy emission event may be comprised of the TPS 120 emitting light for more than 75% of the indicated duration in time, while an "off' energy emission event may be comprised of the TPS 120 emitting light for less than 25% of the indicated duration in time. Other percentages or thresholds are possible as well.

[0069] In an embodiment of the present invention, an "on" emission event or an "off' emission event may also be signaled, in whole or in part, by a level of energy emitted during the energy emission event. For example, a level of energy emission greater than an on-modulation threshold level of energy may signal an on-bit in the energy modulation pattern. Similarly, if the level of energy emission during part or all of the energy emission event is maintained at below an off-modulation threshold level of energy, this may signal an off-bit in the energy modulation pattern.

[0070] In an alternative embodiment of the present invention, a single energy emission event may use varied levels of energy emission, varied frequencies of energy emission, varied phases of energy emission, varied durations of energy emissions, or varied polarizations of energy emission, or a combination of the above, to signal multiple bits in a modulation pattern. For example, in one embodiment a substantially maximum level of energy emission may signal '11 ', a substantially zero level of energy emission may signal '00', while intermediate levels of energy emission may signal '01' and '1 0'. Other energy-level/bit-pattern systems may be employed as well.

[0071] Throughout the remainder of this document it is assumed, by way of an exemplary embodiment of the

6 Jul. 5, 2007

invention, that a single energy emission event may correspond to a single bit in an energy emission pattern, i.e., to a '1' value or a '0' value, but alternative embodiments are possible as described immediately above.

[0072] If an "on" energy emission event is represented as a '1 ', and an "off' energy emission event is represented as a '0', then TPSs may have modulation patterns such as '11111110', '10101010', '11110001', and other modulation patterns. The patterns shown here are 8-bit patterns, but longer or shorter patterns may be used, provided the length of the patterns is sufficient to provide each TPS 120 with a unique modulation scheme. The modulation scheme may include error correction and validation sequences.

[0073] As will be discussed further below, the method of the present invention may employ at least two variations on the modulation scheme shown. In one variation, known as the "synchronous" modulation scheme, the timing of the TPS 120 modulation will be substantially synchronized with the perceptions frames of the VTD array. In this synchronous variation, a TPS 120 may use every energy emission event (i.e., a single period which allows for an "on" emission or an "off' emission) for a single bit of modulation. Therefore, all potentially available bits may be used for signal modulation.

[0074] In another variation, known as the "isochronous" modulation scheme, the energy emission events may be deliberately set to have a duration such that, over a plurality of such events, the energy emission events repeatedly become in phase with the VTD 110 perception frames and then out of phase with the VTD 110 perception frames. In this isochronous modulation scheme, a TPS 120 may use some energy emission events as "beacons", wherein light is always emitted. In essence, these bits are always used to announce that some TPS 120 is present, without identifying which TPS 120 is emitting the light. The TPS 120 may then use only the remaining energy emission events for signal modulation.

[0075] In one embodiment of the isochronous modulation scheme, a TPS may use alternate energy emission events for modulation, these then being known as modulation events. The remaining alternate energy emission events are the beacon events. This corresponds to every alternate available bit being used as a modulation bit, which conveys part of the modulation pattern. In an alternative embodiment of the isochronous modulation scheme, fewer than 50% of the available energy emission events, and therefore fewer than 50% of the potentially available signaling bits, are used to convey the modulation pattern. The remaining energy emission events, i.e., greater than 50% of the energy emission events, are used to transmit light and so serve as beacon events.

[0076] In step 225, the VTDs 110 are used to monitor the TPSs 120. This step is discussed further below.

[0077] In step 230, the VTDs 110 deliver to the DAE 140 location-related data for the TPSs 120 within their field of view. If a TPS 120 can be identified as a previously identified TPS 120, the method of the present invention may continue with step 235. If a TPS 120 is flagged by VTD 110 or DAE 140 as a new TPS 120, the method of the present invention may continue with step 275 instead.

[0078] In step 235, in one embodiment of the present invention, the DAE 140 re-identifies TPSs 120 on successive


US 2007/0152157 AI

video frames using tracking and sorting algorithms, which may also employ previously identified path and motion data discussed further below. In an alternative embodiment of the present invention, some or all of the re-identification of TPSs 120 on successive video frames may be performed by the VTDs 110 rather than, or in combination with, the DAE 140. In order to perform step 235, DAE 140 may receive data feedback 237 from successive steps 240, 245, 250, 255, and 260.

[0079] Note that in one embodiment of the present invention, step 235 may be skipped when the simulation is first initialized, and there may be no identified TPSs 120 to re-identifY. In an alternative embodiment step 235 may be implemented from the outset; any TPS 120 identity data, if needed, may be available from preprogrammed data, or from other sources.

[0080] In step 240, in one embodiment of the present invention, the DAE 140 generates per-point (that is, per TPS 120 per VTD 110) location-data history tables. In an alternative embodiment of the present invention, some or all of the generation of the per-point location-data tables may be performed by the VTDs 110 rather than, or in combination with, the DAE 140.

[0081] In step 245 the DAE 140 correlates location-related data from multiple VTDs to determine the three-dimensional position (i.e., the location in the arena) of the TPS 120. The details of this step are discussed further below.

[0082] In step 250, in one embodiment of the present invention, the DAE 140 identifies the TPS 120 as a particular, unique TPS based on the unique energy modulation pattern of the TPS 120. In an alternative embodiment of the present invention, some or all of the identification of the TPS 120 as a particular, unique TPS based on the modulation pattern of the TPS 120 may be performed by the VTDs 110 rather than, or in combination with, the DAE 140.

[0083] In step 255, the DAE 140 analyzes time-series positions of the TPS 120 to determine a path of motion of the TPS 120 and to determine equations of motion of the TPS 120.

[0084] The entity to which the TPS 120 is attached may have multiple components or elements, which may be engaged in complex motions. In addition, multiple entities may be present in the arena, and the arena may also have structural elements of its own. As a result of all of these factors, at times the view of a TPS 120 may be obstructed by other objects, such that only one VTD 110 or no VTDs 110 may be able to view the TPS 120. Also, the modulation of the energy emission from the TPS 120 may result in the VTDs 110 and/or the DAE 140 being unable to identifY or to track the TPS 120 for a period of time. In this event, in step 260 the DAE 140 extrapolates an anticipated new position for the TPS based on the previously determined TPS position, path, and/or equation of motion.

[0085] In step 270, the DAE 140 or the VTDs 110, or possibly both in combination, identifY a TPS 120 which cannot be immediately identified as a successive stage in motion of a TPS 120 in step 235. The TPS 120 is then classified as an apparently new TPS 120. In step 275, the DAE 140 determines whether the apparently new TPS 120 is actually new, or whether it is a previously identified TPS 120 which had been blocked from view, or where the

7 Jul. 5, 2007

tracking had otherwise been lost, wherein the previously identified TPS 120 has now been reacquired. If the TPS 120 is a new TPS 120, the DAE 140 will attempt to identifY it via the modulation pattern it emits, and then associate the TPS 120 with one of the TPSs 120 previously programmed into it in step 205.

[0086] It should be understood that the steps presented above represent only one embodiment of the present invention. In some embodiments, the steps may be performed in a different order, or some of the steps may be performed in parallel. In addition, other steps may be performed as well. For example, an entity 130 in the arena 100 may have two or more TPSs 120 attached to it; then, in an additional step, DAE 140 may be able to use the location data for each of the attached TPSs 120 to determine the orientation in space of the entity 130, the angular movement of the entity 130, and the angular or rotational equation of motion of the entity 130.

Locating a TPS

[0087] In each perception frame, a VTD 110 sorts out and identifies point light sources in its field of view, where the sources of the light are one or more TPSs 120. The images of point sources detected by the VTD 110 are reduced to a pair of angles for horizontal and vertical displacement from the center of the VTD 110 field of view. By combining the known positions/perspective of each VTD 110 and the angles for each TPS 120 relative to each VTD 110, the system may resolve TPS 120 coordinates in three dimensions at any given time. In what follows, it will be understood that the necessary mathematical calculations may be performed by a one or more VTDs 110, or the DAE 140, or a combination of the DAE 140 and the VTt)s 110.

[0088] The VTD 110 may be composed of an infrared sensitive image capture device coupled to a processing array, which may be on the backplane of the VTD, that detects points in the field of view which match the criteria for TPS 120 emitters. When the processing array detects a match for a TPS it uses the pixel values which compose the TPS 120 image to compute an optical centroid for that TPS 120. The centroid for the TPS is analogous to a center of mass, except that the centroid here represents a center of optical intensity for the TPS 120, instead of a center of mass. This centroid determination is performed for all TPSs 120 detected in each image frame captured by a VTD 110.

[0089] The VTD may translate the image pixel centroid into an angular measurement offset in the horizontal (a) and vertical (/c) axes. These angles may be corrected based on tables stored in the VTD to compensate for spherical asymmetries inherent in the lens systems used in digital imaging systems to create a' and /c'. A further correction may be performed in order to convert the viewed image into arena space ordinal angles and displacements. This latter correction may be performed at the VTD 110, or may be performed at the DAE 140.

[0090] FIG. 3 illustrates a method 300 for the computation of the location of a TPS 120 in the arena 100, where the TPS 120 is in the field of view of VTDs 110. VTD 110s are installed in a fixed relationship to arena 100. The view shown is two-dimensional, and may be presumed to be a view looking up from an arena floor or down from an arena ceiling, not shown, where the view is perpendicular to the


US 2007/0152157 AI

ceiling or floor (i.e., the elements seen, one TPS 120 and two VTDs 110, are as would be seen looking straight down from the ceiling or straight up from the floor). Each VTD 110 observes the arena 100 from a fixed perspective. This allows direct computation of a TPS 120 location from VTD 110 observation angles, measured as offsets from horizontal and vertical planes, of a projected ray corresponding to the TPS 120. (How the projected ray is determined by a VTD 110 is discussed further below in conjunction with FIG. 4.)

[0091] In one embodiment of the present invention, the system employs infrared light sources in each TPS 120. The light sources, i.e., the emitters within the TPSs 120, are modulated, as already discussed in general terms above (and as discussed in further detail below) to identify players and entities 130 in the arena 100. Rays of light from the TPSs 120 strike the backplanes 320 ofVTDs 110 when the TPSs 120 are within the field of view of the VTDs 110. It will be understood that the backplanes 320 are the internal imaging surfaces of the respective VTDs 110, which are presumed for this embodiment of the invention to be flat, and which are further presumed to be in parallel to any VTD 110 lens which focuses light onto the backplanes. It will be understood by persons skilled in the relevant arts that if, in alternative embodiments of the present invention, the VTDs 110 employ a substantially different internal architecture (i.e., with a more complex imaging architecture, which may, for example, embody mirrors or other imaging elements as part of the focusing mechanism) than that illustrated in FIG. 3 and described herein, then suitable modifications or adaptations may be required in the exemplary calculations which follow.

[0092] In FIG. 3, a represents the angle of incidence of a ray oflight 310 from a TPS 120 relative to the backplane 320 of a VTD 110, where a may be a horizontal angle of incidence. (A vertical angle of incidence A is not illustrated.) ~ represents the angle between the VTD backplane 320 and the wall 330 of the arena 100. y is determined from a and~· For example, in the configuration illustrated,

y~180°-(a+i)).

[0093] In the embodiment illustrated in FIG. 3, two VTDs 110a and 110b have captured rays of light 310a and 310b, respectively, from the TPS 120, and corresponding incidence angles yl and y2 may be calculated for the two VTDs. The two VTDs 110a and 110b share a common wall 330, with a known length Len. Based on this, a length representing the orthogonal distance from wall 330 to TPS 120 may be calculated as:

Len3 ~tan(y2)*Len/tan(yl)

[0094] Further, from the arena 100 geometry depicted, it is evident that a second length, Len 2, measured from the corner of the arena containing VTD 110b to the point of intersection of the perpendicular connector between TPS 120 with wall 330 can also be determined as:

Len2~Len3/tan(y2)

[0095] With Len3 and Len2 determined, the location of TPS 120 in two dimensions, relative to the walls of the arena 100, has now been determined.

[0096] Persons skilled in the relevant art(s) will appreciate that while the foregoing calculation has only determined the location of the TPS 120 in two dimensions, the location of the TPS 120 in three dimensions can be readily determined

8 Jul. 5, 2007

via analogous calculations, provided additional data is present. The additional data may be an additional pair of angles for each VTD 110, wherein one angle in the pair indicates an angle of orientation between the backplane of the VTD 110 and an arena 100 ceiling or floor (not shown), while a second angle A (not shown) represents the vertical angle of incidence of the light 310 from the TPS 120 on the backplane 320 of the VTD 120.

[0097] Persons skilled in the relevant art(s) will also appreciate that other configurations or layouts of the area 100 space and the VTDs 110 may require variations on the formulas shown, but that in all cases it is possible to calculate the location of a TPS 120 provided the necessary information of angular incidence oflight on the backplane is captured from a VTD or VTDs 110.

[0098] FIG. 4A and FIG. 4B together illustrate an approach 400 for locating a TPS 120 in a VTD 110 field of view, and hence for identifying an angle a, where a represents the angle of incidence of a ray oflight 310 from a TPS 120 relative to the backplane 320 of a VTD 110 (as discussed in conjunction with FIG. 3, above).

[0099] FIG. 4A illustrates a VTD 110 observing two TPSs 120, with rays oflight 310 from the TPSs 120 striking a lens or other optical element (not shown) of the VTD 110. The lens or other optical elements, possibly in combination with other optical elements (not shown) focuses the rays of light 310 from the TPSs 120 onto backplane 320 (i.e., the imaging element) ofVTD 110. The backplane 320 is here represented as a matrix of discrete pixel elements 410 (i.e., sensor cells), which may be physical pixel elements, or which may be logical pixel elements derived from a scanning process or similar process which extracts image information from a continuous light sensitive media of backplane 320. Together, discrete pixel elements 410 comprise a digitized field of view of the TPSs 120 within the field of view ofVTD 110. Each TPS 120 light source may be perceived by the VTD 110 as a heightened area of sensed light intensity in a bounded area 420 of the digitized field of view.

[0100] FIG. 4B illustrates how different pixel elements or sensor cells 410 in the bounded area of detection 420 may detect different degrees of light intensity. In the figure, the light intensity is exemplified by the height of a pixel element 410. (The "height" is representational only, corresponding to a recorded light intensity, and does not correspond to a physical, structural height of a pixel in a physical backplane or imaging element.) Pixel element 410 may only be considered to have detected light from a TPS 120 if the measure of light intensity from the pixel element 410 exceeds a threshold value.

[0101] The pixel elements or sensor cells 410 used to compute a centroid are separated by their amplitude, grouping, and group dimensions. The center of a TPS 120 image on the backplane 320 is located by finding the optical centroid CXc, YJ of the TPS 120 light source, using the equations:

Xc~(Tixv * Xxv)i:f:.Ixy

Yc~CLixy * Yxy)i:f:.Ixy

[0102] where Ixy is the measured light intensity of a pixel element 410 within the area of detection 420, Xxy is the X-coordinate of the pixel element 410 relative to the area of


US 2007/0152157 AI

detection 420, and Y xY is the Y-coordinate of the pixel element 410 relative to the area of detection 420.

[0103] Corrections may be applied to the computation of this centroid. The first of these corrections is a temperature based offset of intensity amplitude on a per cell basis. The second compensation is the exact X:Y location of each cell based on corrections for errors in the optics inherent in VTD 110. These corrections are applied locally prior to the centroid computation being made for each TPS centroid.

[0104] Once a determination has been made of the XYposition of the centroid, the offset angles from the center of the VTD field of view at which rays of light from the TPS impinge on the TPS backplane 320 can be readily determined using calculations which are well-known in the art. So, for example, the angle a illustrated in FIG. 3, which represents an angle of incidence of a ray of light 310 from a TPS 120 relative to the backplane 320, may be calculated according to the method described here.

[OlOS] In one embodiment of the present invention, the calculations described above may be performed by VTD 110. In another embodiment of the present invention the calculations may be performed by DAE 140.

[0106] In an embodiment of the present invention, it may not be possible for a VTD 110 to determine perfectly precise angles for the location of the TPS 110 centroid, but rather a range of angles which determine a spatial cone in which a TPS be considered to be contained with a high degree of probability. FIG. S illustrates a single TPS 120 which is within the field of view of two VTDs lOOa and lOOb. Pairs of lines SlOa and SlOb extending from each VTD 110a and 110b respectively indicate an angular range within which each VTD 110 has determined a high probability that the TPS 120 may be found. The intersection of pairs of lines SlOa and SlOb determines a substantially localized region S20 within which there is a high probability that the TPS 120 may be found.

[0107] For simplicity of viewing only two lines SlO are shown extending from each VTD 110, implying a planar location determination S20; persons skilled in the relevant arts will appreciate that a full determination will involve a cone of high probability extending from each VTD 110, with a corresponding, substantially localized volume of high probability ofTPS 120 location determined by the intersection of the cones. If the TPS 110 is in the field of view of more than two VTDs 110, the intersection of more than two cones of probability may result in an improved location determination for the TPS 110.

[0108] In an embodiment of the present invention, in addition to determining the location of the TPS centroid, and from there an angle of incidence of the light from the TPS 120, the method of the present invention may also record a light intensity of the centroid, such as a maximum intensity or an average intensity, or other intensity data. This intensity data may be used as a means to perform an estimation of the distance of a TPS 120 from a VTD 110, wherein a greater light intensity may correspond to a closer distance between TPS 120 and VTD 110, and a lesser light intensity may correspond to a greater distance between TPS 120 and VTD 110. This estimation of distance may be used to check, confirm, or otherwise correlate with or supplement TPS 120 location determinations which are made via other methods of the present invention.

9 Jul. 5, 2007

TPS Identification

[0109] As described above in conjunction with FIG. 3, in order for a determination to be made of the location of the TPS 120, the TPS 120 may need to be "seen" or identified in the same perception frame by at least two VTDs 110. In turn, this may require that the TPS 120 image which is seen by a VTD 110 can be identified as being associated with a particular TPS 120, so that two VTDs 110 may both report that they have location-related data for the same TPS 120. Put another way, a key to matching a TPS 120 viewed by different VTD 110s may be the ability to uniquely identifY a TPS 120 in the field of view of each VTD 110.

[0110] In an embodiment of the present invention, a VTD 120 is identified by its energy emission pattern, i.e., by the way it modulates its light emission on and off. Since the energy may be modulated on a per-perception frame basis, it may be necessary for a VTD 110, or for a DAE 140 which processes VTD data, to identify a TPS 110 which has moved in space, and has therefore moved in the VTD 110 field of view, from one perception frame to the next. In tum, to identify a TPS 120 from one perception frame to the next may require that a VTD 110 or DAE 140 be able to anticipate an approximate expected location for a TPS 120 which has already been seen.

[0111] The method of the present invention computes an equation of motion for each TPS 120 based on a recent past history of movement by the TPS 120, where the recent past history may comprise TPS 120 location from two or more perception frames, several seconds of successive perception frames, several minutes of successive perception frames, or a longer series of perceptions frames. Because TPS 120 energy emissions are modulated on and off, the equations of motion may be derived based on location-related data from perception frames which are not necessarily consecutive, i.e., where there are gaps in the perception frames. Equations of motion may include both path equations, which may take the form of algebraic equations which delineate a path in three-dimensional space, and equations for TPS 120 velocity and acceleration, which may be first and second order differential equations.

[0112] By computing equations of motion at each VTD 110, it may be possible to enable a substantially continuous tracking of a VTD 110. In turn, this substantially continuous tracking may make it possible to detect when a VTD 110 modulates its light emission. This modulation is decoded as a serial message which includes the identification of the TPS 120. (The details of TPS modulation are discussed further below.)

[0113] Once a TPS 120 centroid is established for more than one frame period, a process of identifying the TPS 120 is begun. To this end a radial bubble sort process 600 is employed to re-identifY the TPS 120 on each successive perception frame. FIG. 6 illustrates both the basic components and the steps in this process.

[0114] DAE 140 maintains a TPS list 60S of each currently known TPS 110, i.e., each TPS 110 which has been previously identified. DAE 140 also maintains a list 610 of a previously calculated equation of motion for each TPS 120 in list 60S.

[011S] For each perception frame, motion equations 610 for each known TPS 120 may be advanced to the current


US 2007/0152157 AI

time, resulting in a list of extrapolated TPS positions 615. The predicted (i.e., extrapolated) positions of the known TPSs 120 may then be compared to detected TPS 120 positions via a radial distance computation 620. Allowed distances, i.e., allowed radii 622 for the radial distance computation 620 may vary on a per-TPS basis, and may be determined via a velocity-based window sizer 622, which determines allowed radii depending on the predicted velocity of the known TPSs. (This is discussed further below.)

[0116] These distances, i.e., the distances between extrapolated positions of known TPSs and currently detected TPSs, are then sorted using a radial closest match algorithm 625 to yield a best fit between predicted TPS 120 positions and observed TPS 120 positions. The sorting algorithm employed may be a bubble sort, or some other sorting algorithm may be used. When a radial match occurs, meaning a currently detected TPS has been determined to be the same as a previously identified TPS, the TPS history 605' and equations 610' are updated for the next frame.

[0117] In an embodiment of the present invention, a maximum allowed radius is established, wherein this maximum allowed radius determines a maximum distance that a TPS may be expected to move from one perception frame to the next. This maximum allowed radius may be based on a number of factors including, for example and without limitation, a user-defined or pre-programmed absolute maximum radius for an entire simulation run or part of a simulation run; a maximum radius for a TPS based on the previously calculated velocity or equation of motion of the TPS, wherein this maximum allowed radius may be varied over time as it is determined that the equation of motion changes; or a maximum allowed radius for the type of entity to which the TPS is attached. For example, the maximum allowed radius for a TPS attached to a powered vehicle may be greater than the maximum allowed radius for a TPS attached to a person whose means of locomotion is limited to walking or running.

[0118] If a TPS 120 centroid falls out of the maximum allowed radius, then it is assumed to be a new TPS 120 and a new set of equations are started. When a TPS 120 is not detected on a given frame, the equations are coasted and the TPS 120 entry may be marked as modulated. (TPS modulation is discussed further below.) "Coasting" of a TPS means that a future position of the TPS is extrapolated based on a known (i.e., measured) past position and based on the previously determined equation of motion for the TPS 120. TPS 120 equations may be coasted for a certain number of frames, then deleted as a valid entry ifthere is no subsequent re-identification. In one embodiment of the present invention, the threshold number of frames beyond which a TPS 120 may be considered invalid if not re-identified is a fixed, set number of frames for all TPSs 120 within the simulation.

[0119] In an alternative embodiment, the threshold number of frames for TPS 120 invalidation may be varied depending on a number of factors including, for example and without limitation, a velocity of a TPS 120, an acceleration of a TPS 120, a global spatial density of TPSs 120 within the arena environment, a local TPS 120 spatial density in the vicinity of the TPS 120, or a determined accuracy rate or error rate of TPS 120 re-identification.

[0120] In an embodiment of the present invention, two or more distinct, currently detected TPSs 120 may be deter-

10 Jul. 5, 2007

mined to both possibly be a previously identified TPS 120, or two or more distinct previously identified TPSs 120 may both be determined to possibly be a currently identified TPS 120. A range of strategies may be employed to respond to these ambiguous cases including, for example and without limitation:

[0121] withholding any assignment of a newly identified TPS 120 to a previously identified TPS 120 until additional data has been gathered in one or more following perception frames;

[0122] making a tentative or provisional assignment between a newly identified TPS 120 and a previously identified TPS 120, but reevaluating the assignment based on additional data gathered in following perception frames;

[0123] retaining current frame analysis data for use in later reevaluation;

[0124] providing notifications to users and/or simulation operators of the possibility of an incorrect TPS 120 identification;

[0125] providing to TPS 120 users and/or simulation operators an opportunity for human intervention to validate and/or correct a known-TPS/newly-identified-TPS assignment (wherein the human intervention may entail pausing the simulation; or may entail allowing the simulation to continue in a full mode or a limited mode of operation, even while ambiguous data is being subject to human validation or correction).

TPS Modulation

[0126] Each TPS 120 uniquely identifies itself to the system via a unique modulation pattern of its light or energy emission. TPSs 120 may use a synchronous message in the identification process, which is decoded by the DAE 140 as part of the tracking processing. TPSs 120 may use an isochronous message in the identification process which is decoded by the DAE 140 as part of the tracking processing. Alternatively, this decoding may be done at the VTD 110s. Both the synchronous modulation process and the isochronous modulation process are discussed further below.

[0127] In an embodiment of the present invention, TPSs 120 may also use emissions of light energy at varied frequencies (for example, at varied frequencies within the infrared range) as an alternate or additional means of signaling TPS 120 identity, TPS 120 orientation, or other pertinent TPS 120 data.

Synchronous TPS Modulation

[0128] In an embodiment of the present invention, the synchronous modulation scheme may be enabled in part by a means to ensure that the perception frames of all VTDs 110 in the arena 100 are substantially synchronized in time. For example, all the VTDs 110 may be connected to a local area network (a LAN) which synchronizes the perception frames of all VTDs 110, or a single master VTD 110 may send a synchronization signal to all the other VTDS 110 in the arena. Other methods and means to substantially synchronize the perception frames of the VTDs 110 may be employed as well.

[0129] The synchronous modulation scheme may be further enabled by means of an enhanced TPS 120. An enhanced TPS 120 may contain a means for receiving a


US 2007/0152157 AI

signal, wherein the signal may be, for example and without limitation, a radio frequency signal (i.e., a wireless signal), an infrared signal (which may be at a different infrared frequency than the infrared frequency emitted by the TPS 120), a magnetic signal, a laser signal, an electromagnetic signal, or an audio signal.

[0130] The synchronous modulation scheme may further comprise synchronizing the energy emissions (for example, the infrared light emissions) of the TPSs 120 with the perception frames of the VTDs 100 by means a synchronization signal, wherein the synchronization signal may employ one of the transmission means or media described immediately above (e.g., a wireless signal, a laser signal, an infrared signal, an audio signal, etc.).

[0131] The synchronization signal may take the form of a brief pulse of energy which signals the enhanced TPSs 120 that a perception frame has begun, wherein each enhanced TPS 120 may then transmit a bit in its modulation scheme, wherein each transmitted bit is substantially synchronized with the beginning of the VTD perception frames. The synchronization signal may be emitted by a master VTD 110, or may be emitted by some other master device, such as a network server (which may be the DAE 140) which also synchronizes the VTDs 110. Other sources of synchronization are possible as well.

[0132] Within the time span (i.e., the duration) of a perception frame, a VTD 110 may have an interval of maximum light perception, wherein the interval of maximum light perception is shorter than the overall duration of the perception frame. In an embodiment of the invention, a TPS 120 which is synchronized to the VTD 110 sampling period may allow shortened light emissions from the TPS 110; that is, the TPS 120 may only emit energy during part of the energy emission event 703, and preferably during an interval which coincides with or at least partially overlaps with the peak sensitivity of the VTD array's sensors 110. This may result in reduced power consumption and a longer time of operational use of a TPS 110 before the TPS 110 power source (e.g., a battery) needs to be replaced or recharged.

[0133] FIG. 7A illustrates the synchronous modulation scheme 700 according to one embodiment of the present invention. Periods of time where the TPSs 110 emit light energy are referred to as energy emission events 703. All energy emission events 703 are substantially synchronized with perception frames 702, wherein there exist pairings 705 of perception frames 702 and energy emission events 703. Because the timings of the energy emission events 703 and perception frames 702 are substantially synchronized, each energy emission event 703 may be used to convey a single bit of modulation pattern data, with substantially minimal risk that the VTDs 110 may miss a modulation pattern bit.

[0134] In exemplary modulation scheme 700 there may be 16 perception frames per second. In a simulation which uses two hundred and fifty-five (255) or fewer TPSs 120, an 8-bit modulation scheme 730a may be used to uniquely identify each TPS 120. (While 8-bits allow for two hundred and fifty-six (256) modulation patterns, one of those patterns would be all zeros, meaning the TPS 120 assigned that modulation pattern would never transmit any signal, and hence would not be identified or tracked. This means that an 8-bit scheme may only allow for two hundred and fifty-five TPSs 120.) Hence, a TPS 120 may transmit its entire 8-bit

11 Jul. 5, 2007

modulation scheme 730a in eight energy emission events 703, where each energy emission event 703 from the TPS 120 is used to convey one bit 720a of the TPSs 110 unique modulation pattern 730a. FIG. 7A illustrates how there is one modulation bit 720a corresponding to each sequential bit number 710a. As a result, the TPS 120 may identifY itself to the VTDs 110 twice per second.

[0135] In synchronous modulation scheme 700, some unique modulation patterns may have a high ratio of offemissions (no light is emitted by TPS 120) as compared to on-emissions (light is emitted by TPS 120). Examples of such modulation patterns may be "00000001", "00000010", etc. Put another way, some unique modulation patterns may have a low duty cycle of energy emission. As a result, both the VTDs 110 and the algorithms and methods 200, 300, 400, 500 and 600 to track TPS 120 location may have insufficient data to reliably and consistently track some TPSs 120.

[0136] FIG. 7B illustrates a method for synchronous modulation 750 according to an alternative embodiment of the present invention wherein all TPSs may maintain a higher duty cycle, which may result in improved tracking and identification reliability. In this method 750, a subset of perception frames 702 may be associated with modulation bits, wherein the TPS 120 modulates its energy emissions according to a unique modulation pattern, represented by modulation bits 720b; while the remaining perception frames 702 may be associated with beacon bits 725b, which are marked in FIG. 7B with the letter 'B', wherein for each energy emission event corresponding to a beacon bit 725b the TPS 120 always emits energy, i.e., the TPS 120 is always modulated on.

[0137] In the exemplary embodiment shown in FIG. 7B, energy emission events 703 corresponding to odd-numbered perception frames 702 are used to convey modulation pattern data, and so may be modulated on or off; while energy emission events 703 corresponding to even-numbered perception frames 702 always correspond to beacon bits B, and so are always modulated on (i.e., light is always emitted). As a result of synchronous modulation scheme 750, the overall duty cycle exhibited by the TPS 120 may be higher than may be the case with synchronous modulation scheme 700, which may result in improved TPS 120 tracking reliability.

[0138] Persons skilled in the relevant arts will appreciate that the synchronous modulation schemes 700 and 750 described above are exemplary only, and that variations on these synchronous modulation schemes may be employed within the overall scope of the present invention. In an embodiment of the invention, a TPS 120 using a synchronous modulation scheme may modulate its emitter with a message no less frequently than every other perception frame period.

[0139] In an alternative embodiment of the present invention, the TPSs 110 may be further enhanced to not only received a synchronization signal, but to transmit additional data via the same link used for the synchronization signal or via another link. For example, by means of a wireless link each enhanced TPS 120 may communicate its orientation and rotation relative to an initial vector established during initialization of the simulation.


US 2007/0152157 AI

[0140] In an alternative embodiment of the present invention, the enhanced TPS 120 may receive a message to modulate its infrared emitter on or off as an alternate scheme to identifY the TPS 120.

Isochronous TPS Modulation

[0141] As noted above, a synchronous modulation scheme may be employed to synchronize the timing the of each TPS 120 energy emission event with the VTD 110 perception frames. However, such a scheme may involved greater complexity for each TPS 120, which may also result in greater system cost. A modulation scheme which may result in reduced system complexity and may result in reduced system cost is an isochronous modulation scheme, which may also be known as a moving window transmission scheme.

[0142] A TPS 120 may implement isochronous messaging to adapt to reception by a VTD 110 array where no synchronization is inherent between the VTD array 110 and the TPSs 120. (The VTDs 110 in the VTD array, however, may still have their perception frames synchronized with each other.) In an embodiment of the invention each TPS 120 may have a duration of an energy emission event, wherein the duration of the energy emission event may be fractionally longer or fractionally shorter than the duration of a perception frame. In turn, this means that each successive energy emission event from a TPS 110 will "slip", or shift its start time, by a fractional part of the duration of a perception frame.

[0143] In an exemplary embodiment of the present invention, a VTD 110 perception frame may be 1.!t6th of a second in duration. In turn, an energy emission event from a TPS 120 may have a duration which is substantially close to 15/1t' of that duration, or in other words, to 15.!t6ths of 1.!t6th of a second, i.e., 15hs6ths of a second. As a result,on each successive energy emission event the TPS 120 slips the start time by 1.!t6th of a the duration of a perception frame (that is, by approximately 6%) on each successive perception frame period.

[0144] For example, on some particular perception frame, the TPS 120 may begin an energy emission event precisely at or substantially at the beginning of the VTD 110 perception frame. The TPS 120 may then begin its next consecutive energy emission event 1.!t6th of a frame interval before the end of the first perception frame interval, and therefore 1f16th

of a frame interval before the start of the next consecutive perception frame.

[0145] In this isochronous modulation scheme, over an extended period of time (which may span several seconds or longer), there may be intervals of time (which may span a plurality of perception frames) where the TPS 120 energy emission events may be substantially synchronized with the VTD 110 perception frames; and there may also be intervals of times (which may span a plurality of perception frames) where the TPS 120 energy emission events may be substantially not synchronized with the VTD 110 perception frames. In an embodiment of the present invention, it may also be the case that when a TPS 120 is modulated on, either to convey an on-bit in a modulation pattern or to convey a beacon bit, the TPS 120 may nonetheless emit light only during a portion or a fraction of the time interval of the energy emission event.

12 Jul. 5, 2007

[0146] FIG. SA shows how an exemplary isochronous modulation scheme SOO permits a VTD 110 to determine the modulation pattern of a TPS 120. Note that in this figure, as well as in FIG. SB discussed below, energy emission events 703, modulation bits 720, and modulation pattern 730 are numbered analogously to the same elements in FIG. 7 A and FIG. 7B. This reflects the possibility that, apart from timing and/or synchronization differences, the TPS 120 modulation scheme and TPS 120 energy emission events may be similar or substantially the same for both the synchronous modulation scheme and the isochronous modulation scheme.

[0147] Put another way, the synchronous modulation scheme and the isochronous modulation scheme may both share a method wherein TPSs 120 are identified by a unique bit pattern (the modulation pattern 730 comprised of modulation bits 720), wherein each bit is signaled by an energy emission event 703. The differences between the two modulation schemes, synchronous vs. isochronous, may then be categorized, in whole or in part, by: (i) a consistent synchronization or lack of consistent synchronization, respectively, between the TPS 120 energy emission events 703 and the VTD 110 perceptions frames 702; and (ii) the means and method by which a VTD 110 or DAE 140 demodulates the TPS 120 modulation pattern 730.

[014S] FIG. SA illustrates a TPS modulation pattern 730 comprised of energy emission events 703, where each energy emission event 703 represents a modulation bit 720. There are off modulation bits S10 and on modulation bits S15, wherein during an on modulation bit S15 the TPS 120 may only emit energy during part of the energy emission event 703. TPS modulation pattern 730d repeats over time as TPS modulation pattern 730e and TPS modulation pattern 730/

[0149] During repetition one (1) of the TPS modulation pattern 730d, the TPS 110 energy emission events 703 may be substantially synchronized in time with perception frames 702. As a result, during each perception frame 702, VTD 110 may obtain a substantially unambiguous energy reading indicating that the TPS 120 either is emitting energy or is not emitting energy. This results in perception frames 702 which receive a clear signal, referred to as distinct signal frames S20; these are represented in the figure by frame blocks filled with either black or white, which in turn represent a substantially unambiguous on-bit (1 value) or off-bit (0 value). This results in a correct reading by the VTD 110 of the TPS modulation pattern 730d.

[0150] During repetition two (2) of TPS modulation pattern 730e, some or all of the TPS 110 energy emission events 703 may be substantially not synchronized in time with perception frames 702. As a result, some perception frames 702 still yield distinct signal frames S20 (though some of these may in fact be erroneous), while other perception frames 702 yield ambiguous signal frames S25, represented in the figure by frame blocks filled with shades of gray. These ambiguous signal frames S25 represent perception frames 702 where little much light was received by the VTD 110 to be unambiguously interpreted as an on-bit (1 value), and at the same time too much light was received to be unambiguously interpreted as an off-bit (0 value).

[0151] During repetition three (3) of TPS modulation pattern 730/, the TPS 110 energy emission events 703 may again be substantially synchronized in time with perception


US 2007/0152157 AI

frames 702, which again results in a correct reading by the VTD 110 of the TPS modulation pattern 730/

[0152] When a VTD 110, or a DAE 140 which receives a signal from a VTD 110, determines that ambiguous signal frames 825 are present over a period of time which may comprise one or a plurality of perception frames, a determination may be made by the method of the present invention that it is not possible to obtain a reliable modulation pattern 730 determination for the TPS 120. This may also be stated as saying that VTD 110 determines that it has received an ambiguous modulation pattern from TPS 120. In that event, the TPS 120 may still be identified by associating it with an extrapolated position of a known TPS 120, as per the methods described above.

[0153] When a VTD 110, or a DAE 140 which receives a signal from a VTD 110, determines that consecutive distinct signal frames 825 are present over a period of time which may comprise at least the number of perception frames required to detect a modulation pattern 730, a determination may be made by the method of the present invention that it is possible to obtain a reliable modulation pattern 730 determination for the TPS 120. This may also be stated as saying that VTD 110 has received an unambiguous modulation pattern from TPS 120, where this determination may be made by VTD 110 or by DAE 140. In this event, TPS 120 may be identified from its modulation pattern 730.

[0154] FIG. 8B illustrates the method of an exemplary isochronous modulation scheme 850 according to another embodiment of the present invention. In this embodiment the VTD 110 may never report an ambiguous signal frame 825, but may instead always report a distinct signal frame 820. However, over time the energy emission events 703 still shift in phase relative to the perception frames 702, as seem from the five phase-shifted TPS modulation patterns 855, which represent successive emissions of the same modulation pattern from a single TPS. As a result, at times energy emission events 703 may be substantially in phase with perception frames 702, during which intervals the VTDs 110 may correctly demodulate the modulation pattern 730. At other times energy emission events 703 may be substantially out of phase with perception frames 702, during which intervals two adjacent energy emission events 703 may both overlap with a single perception frame 702, which may result in an incorrect reading during the perception frame.

[0155] The result is that the received modulation pattern signal 860, i.e., the modulation pattern which is received at the VTD 110 (as opposed to the modulation pattern transmitted by the TPS 120), will be correct sometimes and incorrect other times. When the TPS modulation pattern 730 is received correctly by VTD 110, then the TPS 120 can be identified by that unique modulation pattern 730. These patterns are flagged as "ok" in FIG. 8B. When the TPS modulation pattern 730 is received incorrectly by VTD 110, the incorrect modulation pattern may vary due to variations in the phase differential between perception frames 702 and energy emission events 703, as shown with the two different TPS modulation patterns 730 flagged as errors among received modulation pattern signals 860.

[0156] Even though, with the isochronous modulation scheme 850 of FIG. 8B, there may be intervals when an erroneous TPS modulation pattern 730 is detected, the DAE

13 Jul. 5, 2007

140 and/or VTD 110 may maintain continuous track on a TPS 120. This may be done by recognizing that TPS modulation patterns 730 which are detected may be inconsistent with a previously detected TPS modulation pattern or patterns 730, and may further vary randomly, and therefore do not indicate a new TPS; while TPS modulation patterns 730 which are consistent (i.e., identical) may represent the same TPS 120. Continuous tracking of the TPS 120 via the present method may be further assisted using calculations to extrapolate TPS 120 position, and to associate a newly identified TPS 120 with a previously identified TPS 120 using the closest-match algorithms discussed in conjunction with FIG. 6 above.

[0157] Persons skilled in the relevant arts will appreciate that the isochronous modulation schemes 800 and 850 described above are exemplary only, and that variations on these isochronous modulation schemes may be employed within the overall scope of the present invention.

[0158] In an embodiment of the present invention, a TPS 120 using an isochronous modulation scheme may use a subset of energy emission events 703 for beacon events, wherein energy is always emitted during said subset of energy emission events 703; beacon events may be used to increase the overall duty cycle, which may increase tracking reliability. The remaining subset of energy emission events 703 may then be used by TPS 110 for the modulation pattern 730. In an embodiment of the invention, a TPS 120 may modulate its emitter with a message no less frequently than every other energy emission event.

[0159] In an embodiment of the present invention, a TPS 120 may use different durations of time for energy emission events which are modulated on and energy emission events which are modulated off. A TPS 120 may also introduce additional shifts and variations into the transmission of the modulation pattern. In an embodiment of the present invention, if a sent bit field indicates that no emission is to be made, then the energy emission event may be begun 6% sooner and extended 6% later. In alternative embodiments, different amounts of extension may be used. Once a full modulation pattern has been sent, the presumed perception frame start time may be shifted by a fixed percent and the transmission may be restarted.

[0160] In an embodiment of the present invention, a VTD 110 may modify the duration in time of its perception frame in response to the perceived signal from the TPS 120.

Combined Elements

[0161] FIG. 9 illustrates various aspects of the present invention, as discussed above, working in combination according to one possible embodiment of the invention. A TPS 120 is being modulated as it moves through the arena 100 space, as illustrated by the alternating data bits 720, which are synonymous with the modulation bits 720 discussed above; and the alternating sync bits 725, which are synonymous with the beacon bits discussed above. (Note the sync bits 725 are always modulated on, i.e., the TPS emits light, while data bits 720 may be modulated on or off.)

[0162] DAE 140 receives two-dimensional angular information from multiple VTDs 110, which includes identity information (i.e., TPS 120 modulation data, wherein in the case illustrated the unique TPS modulation pattern 730 is '0011 0'). DAE 140 uses computed 3-dimensional fixes from


US 2007/0152157 AI

various pairs of VTDs 110 to arrive at a bounding space which encloses the actual position ofTPS 120. A curve is fit to the centroid of each of these bounded spaces and is assumed to be the current path 900 of TPS 120. The DAE 140 builds motion formulas and exports motion equation coefficients for each TPS path 900 on a frame by frame basis.

Summary

[0163] While some embodiments of the present invention have been described above, it should be understood that it has been presented by way of examples only and not meant to limit the invention. It will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. Thus, the breadth and scope of the present invention should not be limited by the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

What is claimed is: 1. A method for identifying the location of an entity in a

three-dimensional space comprising:

(a) modulating an energy emission from a source of energy emission, wherein the source of energy emission is attached to the entity, and wherein the energy emission from the source is modulated according to an energy modulation pattern;

(b) monitoring the source using an energy detection device;

(c) obtaining from the energy detection device at least one of the energy modulation pattern of the source or an identification of the source determined by the energy detection device based on the energy modulation pattern;

(d) obtaining from the energy detection device locationrelated data for the source; and

(e) analyzing the location-related data to determine the location of the source.

2. The method of claim 1, wherein the source modulates its energy emission according to an energy modulation pattern unique to the source.

3. The method of claim 1, wherein the energy emission from the source is an infrared (IR) energy emission.

4. The method of claim 1, wherein the energy detection device detects energy from the source during each of a series of perception frames that occur at a periodic perception frame rate.

5. The method of claim 4, further comprising determining an angular movement of the entity by determining over a plurality of perception frames the locations of a plurality of sources of energy emission which are attached to the entity.

6. The method of claim 4, further comprising modulating the energy from the source according to a synchronous modulation scheme, said synchronous modulation scheme comprising:

(i) synchronizing the energy emission of the source with the perception frame of the energy detection device;

wherein a single period of time wherein energy may be emitted or energy may not be emitted from the

14 Jul. 5, 2007

source to signal a single bit in the energy emission pattern is an energy emission event; and

wherein the duration in time of an energy emission event is substantially the same as the duration in time of a perception frame;

(ii) modulating the energy emission from the source on or off during a single energy emission event;

wherein the source is modulated on by at least one of emitting energy for greater than an on-modulation threshold period of time during the energy emission event or emitting energy at greater than an onmodulation threshold level of energy during the energy emission event; and

wherein the source is modulated off by at least one of emitting energy for less than an off-modulation threshold period of time throughout the duration of the energy emission event or emitting energy at less than an off-modulation threshold level of energy throughout the duration of the energy emission event;

(iii) modulating the energy emission from the source on or off over a plurality of energy emission events;

wherein the number of energy emission events in the plurality of energy emission events equals a number of bits in the energy modulation pattern; and

wherein the modulated energy emission over the plu-rality of energy emission events conforms to the energy modulation pattern.

7. The method of claim 6, wherein step (i) further comprises synchronizing the energy emission of the source with the perception frame of the energy detection device by a synchronization signal, wherein the synchronization signal comprises at least one of an infrared signal, a magnetic signal, a radio frequency signal, a laser signal, an electromagnetic signal, or an audio signal.

8. The method of claim 6, further comprising:

(iv) selecting a first subset of the energy emission events as beacon events,

wherein the unique source is always modulated on during a beacon event;

(v) selecting the energy emission events which are not part of the first subset as a second subset of signalmodulation events; and

(vi) modulating the energy emission from the unique source according to the modulation pattern over a plurality of signal-modulation events.

9. The method of claim 4, further comprising modulating the energy from the source according to an isochronous modulation scheme, said isochronous modulation scheme comprising:

(i) establishing a fixed periodic rate of energy emission activity for the unique source, wherein the fixed periodic rate of energy emission activity is substantially close to the perception frame rate but is not the same as the perception frame rate;

wherein each period of energy emission activity from the unique source is an energy emission event, wherein each energy emission event persists for a


US 2007/0152157 AI

period of time which is substantially close to but not that same as the duration in time of the perception frame; and

wherein an energy emission event may be substantially in phase with a perception frame, and wherein another energy emission event may be substantially out of phase with an immediately preceding perception frame and a perception frame which immediately follows the immediately preceding perception frame;

(ii) modulating a consecutive series of energy emission events of the unique source on or off over a plurality of energy emissions events;

wherein the source is modulated on by at least one of emitting energy for greater than an on-modulation threshold period of time during an energy emission event or emitting energy at greater than an onmodulation threshold level of energy during an energy emission event;

wherein the source is modulated off by at least one of emitting energy for less than an off-modulation threshold period of time throughout the duration of an energy emission event or emitting energy at less than an off-modulation threshold level of energy throughout the duration of an energy emission event;

wherein the number of energy emission events in the plurality of energy emission events equals a number of bits in the energy emission pattern; and

wherein the modulated energy emission over the plurality of energy emission events conforms to the energy modulation pattern; and

(iii) determining when a received modulated energy emission from the source which is received by the energy detection device conforms to the energy modulation pattern of the source.

10. The method of claim 9, wherein step (iii) comprises at least one of determining that the energy modulation pattern detected from the source of energy modulation conforms to a previously detected energy modulation pattern of the source or determining that the energy modulation pattern received from the source of energy modulation is an unambiguous energy modulation pattern.

11. The method of claim 4, further comprising determining at least one of a path of movement of the source or an equation of motion of the source based on the location of the source during a plurality of perception frames.

12. The method of claim 11, further comprising extrapolating an extrapolated current position of the source based on at least one of a past location of the source, the path of movement of the source, or the equation of motion of the source.

13. The method of claim 12, further comprising determining that a newly identified source is the same as a previously identified source based on the location of the newly identified source and the extrapolated current position of the source.

14. The method of claim 13, further comprising distinguishing a plurality of newly identified sources of energy emission by using a closest match algorithm to determine which newly identified source is associated with the extrapolated current position of the source.

15 Jul. 5, 2007

15. The method of claim 1, wherein the location-related data comprises at least one of an angular displacement or an energy intensity for the source detected by the energy detection device.

16. The method of claim 1, further comprising monitoring the source using a plurality of energy detection devices.

17. The method of claim 16, wherein each energy detection device detects energy from the source within a field of view of the energy detection device, and wherein at least two of the energy detection devices have an overlapping field of VIeW.

18. The method of claim 17, wherein the location-related data obtained from each energy detection device comprises at least one of a respective angular displacement or a respective energy intensity for the source within the field of view of each respective energy detection device.

19. The method of claim 18, wherein a known location in relation to the three-dimensional space for each of the plurality of energy detection devices is combined with at least one of the angular displacement for the source or the energy intensity for the source within the field of view of each of the plurality of energy detection devices to determine the location of the source during a perception frame.


determining a plurality of volumes in a space, wherein each volume in the space is determined by at least one of a respective angular displacement of the source or a respective energy intensity for the source within the field of view of a plurality of respective energy detection devices; and

determining the location of the source during the perception frame as the intersection of the plurality of volumes.

21. The method of claim 1, further comprising determining at least of one an angular position of the entity or an orientation of the entity by determining the locations of a plurality of sources of energy emission which are attached to the entity.

22. A system for identifYing the location of an entity in a three-dimensional space comprising:

a source of energy emission, wherein the source is attached to the entity, and wherein the source modulates an energy emission according to a unique energy modulation pattern, wherein the source is a unique source;

an energy detection device which monitors the unique source, wherein the energy detection device obtains location-related data for the unique source; and

a means for analyzing the location-related data obtained from the energy detection device, wherein said means determines the location of the unique source, and wherein said means for analyzing location-related data is a data analysis engine.

23. The system of claim 22, wherein the energy detection device detects energy from the unique source during a perception frame, and wherein a first perception frame is followed by a second perception frame at a periodic perception frame rate.

24. The system of claim 23, wherein the unique source modulates the energy emission on and off according to the unique energy modulation pattern at a rate which is substantially synchronized with the perception frame rate of the energy detection device, and wherein over a plurality of


US 2007/0152157 AI

perception frames the energy detection device receives the unique energy modulation pattern of the unique source.

25. The system of claim 24, wherein the unique source synchronizes the energy emission with the perception frame rate of the energy detection device by receiving a synchronization signal from at least one of the energy detection device, the data analysis engine, or a source of a synchronization signal which is synchronized with the energy detection device, and

wherein the synchronization signal comprises at least one of an infrared signal, a magnetic signal, a radio frequency signal, a laser signal, an electromagnetic signal, or an audio signal.

26. The system of claim 23, wherein the unique source modulates the energy emission on and off according to the unique energy modulation pattern at a rate which is not synchronized with the perception frame rate of the energy detection device;

wherein the energy detection device determines when a received modulated energy emission from the unique source which is received by the energy detection device conforms to the energy modulation pattern of the unique source; and

wherein over a plurality of perception frames the energy detection device receives the unique energy modulation pattern of the unique source.

27. The system of claim 26, wherein the energy detection device determines that the received energy modulation pattern received from the unique source conforms to the energy modulation pattern of the unique source by at least one of determining that the received energy modulation pattern conforms to a previously detected energy modulation pattern of the unique source or by determining that the received energy modulation pattern detected from the unique source is an unambiguous energy modulation pattern.

28. The system of claim 22, further comprising a plurality of energy detection devices, wherein each energy detection device of the plurality of energy detection devices detects energy from the unique source within a field of view of the energy detection device, and wherein at least two of the energy detection devices have an overlapping field of view.

29. The system of claim 28, wherein each energy detection device of the plurality of energy detection devices determines location-related data of the unique source by determining at least one of an angular displacement or an energy intensity for the unique source within the field of view of the energy detection device.

16 Jul. 5, 2007

30. The system of claim 29, wherein the data analysis engine combines a known location in relation to the threedimensional space for each of the plurality of energy detection devices with at least one of the angular displacement for the unique source or with the energy intensity for the unique source within the field of view of each of the plurality of energy detection devices to determine the location of the unique source during the perception frame.

31. The system of claim 30, wherein the data analysis engine determines at least one of a path of movement of the unique source or an equation of motion of the unique source based on the location of the unique source during a plurality of perception frames.

32. The system of claim 31, wherein the data analysis engine extrapolates an extrapolated current position of the unique source based on at least one of a past location of the unique source, the path of movement of the unique source, or the equation of motion of the unique source.

33. The system of claim 31, wherein the data analysis engine determines that a newly identified source is the same as a previously identified unique source based on the location of the newly identified source and the extrapolated current position of the unique source.

34. The system of claim 22, wherein the unique source emits energy comprised of infrared light and wherein the energy detection device detects energy comprised of infrared light.

35. The system of claim 22, wherein a single period of time wherein energy may be emitted or energy may not be emitted from the unique source to signal a single bit in the energy emission pattern is an energy emission event; and

wherein the unique source is modulated on by at least one of emitting energy for greater than an on-modulation threshold period of time during the energy emission event or emitting energy at greater than an on-modulation threshold level of energy during the energy emission event; and

wherein the source is modulated off by at least one of emitting energy for less than an off-modulation threshold period of time throughout the duration of the energy emission event or emitting energy at less than an off-modulation threshold level of energy throughout the duration of the energy emission event.

* * * * *


c12) United States Patent Calvarese

(54) IDENTIFYING RFID TAG MOVING COHERENTLY WITH READER

(75) Inventor: Russell Calvarese, Stonybrook, NY (US)

(73) Assignee: Symbol Technologies, Inc., Holtsville, NY (US)


(21) Appl. No.: 11/781,026

(22) Filed: Jul. 20, 2007


US 2009/0021376Al Jan.22,2009

(51) Int. Cl. GOSB 13114 (2006.01)

(52) U.S. Cl. ............................... 340/572.1; 340/539.23 (58) Field of Classification Search .............. 340/572.1,

(56)

340/572.2, 572.7, 10.1, 539.23 See application file for complete search history.

References Cited


7,154,395 B2 * 12/2006 Raskar eta!. .......... 340/539.23

111111 1111111111111111111111111111111111111111111111111111111111111 US007619524B2

(10) Patent No.: US 7,619,524 B2 Nov. 17, 2009 (45) Date of Patent:

7,183,922 B2 * 2/2007 Mendolia eta!. ......... 340/572.1

2008/0007410 A1 * 112008 Rosenbaum et al ...... 340/572.1

2008/0048864 A1 * 2/2008 Mayhew .................. 340/572.1

* cited by examiner

Primary Examiner-John A Tweel, Jr.

(57) ABSTRACT

A system and method to distinguish an RFID tag which is moving synchronously with an RFID reader from other RFID tags which are not moving synchronously with the reader. In one embodiment, the reader emits read signals at a fixed frequency with a corresponding period. A determination is made by the RFID reader as to the signal strengths received from an RFID tag at time intervals which are integer multiples of the half-period of the signal. Signal strengths from the tag which are the same or substantially the same at these prescribed measurement intervals are taken as an indication that the tag is moving synchronously with the RFID reader. In an alternative embodiment, the frequency of the read signals may vary over time. Correlations between received tag signal strengths with particular frequencies are an indication that the RFID tag is moving synchronously with the RFID reader.



U.S. Patent Nov. 17, 2009 Sheet 1 of 13 US 7,619,524 B2

/100

11 Oa ~,-----RE_A_D_E_R-----, J • 112 112~-

~ ~ -,02b 104a)

102a 112~ 112~ 112~ 102c

T ~ 112 102g ~

110b ,'" _R_E_A_D-ER----, J •

102f ~ 112~ 102d

102e 104b)

ANTENNA 202 220

'

' ' '

120

FIG. 1

104

~

r----------------------------------L------------,

RF FRONTEND 204

r-------, 210 r ................. , r············· ..... , MODULATOR! · : : :

ENCODER 208 ~~- : 222 : : 218 - : BASEBAND : ) : NETWORK : )

~=======~ 214 ~PROCESSOR ~..C..~ INTERFACE ~..C.. ~ 212 ~ ~ 216 ~ DEMODULATOR! . . . .

f--"-....... : : :

ENCODER 206 i ~ .................. j ~ ................. _j ' ' I ' ------------------------------------------------'

FIG. 2



102

~

302

IC DIE

MEMORY ~308

IDENTIFICATION e- -----318 NUMBER

~320

CONTROL LOGIC ------- 310

~326 r--..-- 322 ~324


PUMP 314

~ l316 312

r----- 328 l306 ANTENNA r---- 304

FIG. 3


U.S. Patent

I Time: t0 + 2P

I Time: to + P ~

405

!Time: to ~

FIG. 4A

Nov. 17, 2009 Sheet 3 of 13

' ,, " . ~

• ~

\ 023 (:----/ ' •

>" • '·,~ . ..-..../022 \

'~ - ' < .• .. ~ •

' •

US 7,619,524 B2

.. \

• • ~

•

• • ~ " ' .

~

't'\.'"' '\

~~;,, <;, .. ' ~ . " \

Time and Distance

021 '4\ ~ ---------·------ ~ ~ --------------~~ ~ 1

102b

a


U.S. Patent

Time: t0 + 2P

Time: t0 + 3P/2

Time: to+ P

Time: to + P/2

Time: t0

Nov. 17, 2009

420

l

"f~ 202

Sheet 4 of 13

102a ~

420 I Tag1 I

US 7,619,524 B2

Time

)'- 1\ ---- ---- ---- _________ L ___ ~

420 ')

c

"f~ 202

,_;,o2a

420 I Tag1 I l

420 '!

A { ~ __________ L_

~ 202

RFID Reader

FIG. 48

Space



400 ~02b 420

) I Tag21 l

Time: t0 + 2P

T~ 202

1Tag31~ 102c

Time

420 102br-'7\ l Time: t0 + 3P/2 ---- -------- -----

420

l 429"

Time: t0 + P ------~~---T~

202 I Tag3 J~1 02c

420

l Time: t0 + P/2

202 J Tag3 J~1 02c

420

Time: to

l 427'

~----~~~::_ -T-202 429' 1Tag3J

~~~~ ~

Space

RFID ~ 102c Reader 104

FIG. 4C



RSSI 10fa

M [IT] up [IT] qTI [IT] } Mo.nng w;t~ I I I I RFID Reader

I I I I 3M/ I

, .......... 1 ........... 1 I I

Cf1:::1 r:t~:j E':tEl } Mo.nng w;t~ : T1 : : T1 i

I RFID Reader M/2

: .......... I ...... , .. ,I I

I I I I I

I I I I M/4

I

I I I I I

I I I I I

Time to t0 + P/2 to+ P to+ 3P/2 to+ 2P

FIG. SA

550

RSSI 102c

~ +

M ~ I I

I 102b I

+ I

I I Not moving with cp I

<7 I I RFID Reader M/2 I

I qD ~ @

M/4 I I

I I ® ~ I I

I I Time to to+ P/2 to+ P t0 + 3P/2 to+ 2P

FIG. 58


U.S. Patent Nov. 17, 2009

F3 ...... -·-·---· ,..··

// . . .

. . . . . . Reader '-.:-.-•• ---•• -=-'·

.......... .. ... -·

/ ...... ·· _ ................................. ...

. . : : . . . .

"'~ ............. .. RFID

Reader

.................................................

10~ RFID Reader

Sheet 7 of 13 US 7,619,524 B2

666b

F2

F1

FIG. 6

650

················--... \

··.. 664b ./ ·· ....... _c;!. ___________ .

. . I

' : 640 . .

. ........................................ .. 630



F3

F2

F1

' ' ' . . . . . . . . . . . . . ··. ·-.

_, .... ---·············· (/ .-------,

~ . . . . . . . . ·. · ........ .............................

102a

Ira£{ ,,.,. ............... -- ..................................... .. I . ................ _ ...... -- ................................. ----····· -·

Reader

Sheet 8 of 13 US 7,619,524 B2

!·. /

"'~~o...... ,,,-... .................. ..

664c

. ' . ' ' ' ' ' ' .

,/

650

..........................................

62b ·• •• \

··· ...... ____ ? __________ .... 664b

666a

FIG. 7

' . l 640 ' ' . .

30



Time= 6, Freq. = 3

/ .. ··········· ... . .

Sheet 9 of 13

. ........ (.~2\. . . . . . . f \, ,·'' \ . . . . . .

I

Time= 5, Freq. = 1

. . . : . . . : \ . ' . . . ................ -~ " ..... _______ ,,

! . ' . . . . .

[ill (_ ............................... ,... .. ~·-~J--........ ··...,----········-····---..... )

....... ~-·

Time= 4, Freq. = ~--·········-~-~1•••••••••• ..-~ T2 ) .............. \

I •,"' I" • ~

t . .J . •.. . ...... ········· ·············--........... ··

Time= 3, Freq. = 3

Time= 1, Freq. = 1

...... ····--···· .... ' . i "' ..... . . . .

' I . ' . . . . . . ' .

............... •' ................. •~"

666a

FIG. 8

' ' ' . . . ' ' . . . .

62c

US 7,619,524 B2


U.S. Patent Nov. 17, 2009 Sheet 10 of 13

102a

1 2 ~

1 ~

0 ~

2

1

0

F1 FZ F3 Frequency

Correlated: Reader and Tag Moving Synchronously

102b

RSSI l @)@)@)

GDGD

GD

F1 F

2 F

3 Frequency

Uncorrelated: Reader and Tag NOT Moving Synchronously

FIG. 9

US 7,619,524 B2

920



202

( 104

FIG. 10



1100 102z

Tag j <§> <§> } Not moving with

J3 <§> RFID Reader

a <S> ~<S> <S> } Possibly not moving

~ with RFID reader

9 102y ® ®

8 ill)

7 GD QD

6 Not moving with

RFID Reader 5

4 ®

3 ®

2 ® QD 10fa

} Moving with OIJ OIJ OIJ OIJ 0IJ RFID Reader

Time 2 3 4 5 6 7

FIG. 11



Start ~ 1210

Transmit read signals by RFID reader at multiple frequencies, which are

repeated over time.

Receive reply signals from RFID tags within range.

~ 1215

~ 1220

Store data related to received reply signals, including for each reply: ~ 1225

1250 For a given tag, determine degree of correlation between RSSI values and the frequencies of the received replies.

1255

Determine, based on correlation, a degree of likelihood that the given tag is moving coherently with the reader.

1. time 2. tag ID 3. RSSI 4. wavelength

For a given tag, determine degree of consistency of RSSI values at periodic time intervals of the signal.

1245

Determine, based on degree of consistency, a degree of likelihood that the given tag is moving coherently with the reader.

1270

( Stop )

1280

1260

For a given tag, determine degree of continuity of reads overtime, including: 1 . % of time tag seen 2. uniformity of read distribution 3. degree of consecutive reads 4. whether reads span full time period

1265

Determine, based on combination of factors in step 1260, a degree of likelihood that the given tag is moving coherently with the reader.

Combine determinations from steps 1260 and 1280 to make a further determination of likelihood that the given tag is moving

coherently with the reader.

FIG. 12 1280


US 7,619,524 B2 1

IDENTIFYING RFID TAG MOVING COHERENTLY WITH READER

BACKGROUND

The invention relates in general to the use of radio frequency identification (RFID) tags. In particular, the inventions relate to identifying one or more RFID tags that are moving along with a moving RFID reader.

2 simplifications or omissions are not intended to limit the scope of the claimed inventions.

The inventions described in this patent document relate in general to identifYing one or more RFID tags that may be moving along with a mobile reader. For example, an RFID tag affixed to a pallet of goods in a warehouse may be moved by a forklift operator carrying or wearing a reader. Using the techniques described herein, the pallet in motion can easily be distinguished from those that remain stationary or a moving

Radio frequency identification (RFID) tags are electronic devices that may be affixed to items whose presence is to be detected and/or monitored. RFID tags are classified based on standards defined by national and international standards bodies (e.g., EPCGlobal and ISO). Standard tag classes include Class 0, Class 1, and Class 1 Generation 2 (referred to herein as "Gen 2"). The presence of an RFID tag, and therefore the presence of the item to which the tag is affixed, may

10 other than with the reader. In this patent document, movement along with a reader is considered to be "coherent" motion.

The inventions can be implemented in numerous ways, including methods, systems, devices, and computer readable medium. Several embodiments of the inventions are dis-

15 cussed below, but they are not the only ways to practice the inventions described herein.

be checked and monitored wirelessly by an "RFID reader", also known as a "reader-interrogator", "interrogator", or simply "reader." Readers typically have one or more antennas for 20

transmitting radio frequency signals to RFID tags and receiving responses from them. An RFID tag within range of a reader-transmitted signal responds with a signal including a unique identifier.

With the maturation ofRFID technology, efficient commu- 25

nication between tags and readers has become a key enabler in supply chain management, especially in manufacturing, shipping, and retail industries, as well as in building security installations, healthcare facilities, libraries, airports, ware-houses etc. 30

Unlike bar codes, which are read in a line of sight by a laser reader, RFID tags are read wirelessly and not necessarily in a line of sight. This is an advantage in situations where there are tags affixed to objects that can not be seen, such as boxes

35 stacked in a warehouse. An RFID reader in proximity of the tags senses them regardless of whether or not they can be "seen". Although this is an advantage in managing many types of packages and materials, it is a disadvantage in one respect. Because RFID tags are read wirelessly using radio

40 signals, it is not easy to identifY particular tags that are moving coherently (synchronously) with a reader. For example, a forklift operator carrying a reader with him moves a pallet of goods, marked by an RFID tag affixed to the pallet, in a warehouse from point A to point B. There are hundreds of

45 pallets in the warehouse. It may be useful to know which pallet is being moved at that particular time. One way of accomplishing this type of task is to read all tags within range at a point in time. Later, after one or more tags has been moved, the universe of tags remaining is read. Those that

50 produce a read the second time have not been moved and can


The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention.

FIG. 1 shows an environment where RFID readers communicate with an exemplary population of RFID tags.

FIG. 2 shows a block diagram of receiver and transmitter portions of an RFID reader.

FIG. 3 shows a block diagram of an exemplary radio frequency identification (RFID) tag.

FIG. 4A illustrates an exemplary environment where an RFID reader is being moved over some distance, and where a first RFID tag is in synchronous motion with the RFID reader, while a second and third RFID tag are not in synchronous motion with respect to the RFID reader.

FIG. 4B is another view of the exemplary environment of FIG. 4A, including a time series of illustrations showing the relationship between the first RFID tag in synchronous motion with the RFID reader, and a radio frequency wave emanating from an antenna of the RFID reader.

FIG. 4C is another view of the exemplary environment of FIG. 4A, including a time series of illustrations showing the relationship between the second and third RFID tags not in synchronous motion with the RFID reader, and a radio frequency wave emanating from an antenna of the RFID reader.

FIG. SA is an exemplary plot of the energy returned to the exemplary RFID reader of FIG. 4A by the first RFID tag in synchronous motion with the RFID reader. be subtracted from the universe of tags previously read. Tags

that did not read are presumed to have been moved. This process is not convenient for many object management situations.

FIG. SB is an exemplary plot of the energy returned to the exemplary RFID reader of FIG. 4A by the second and third RFID tags not in synchronous motion with the RFID reader.

55 FIG. 6 illustrates exemplary patterns ofRF signal radiation What is needed is a way of easily and quickly determining

which tags are being moved along with an RFID reader in contrast to those tags that are not being moved or are being moved other than along with the RFID reader.

SUMMARY

This section is for the purpose of summarizing some aspects of the inventions described more fully in other sections of this patent document. It briefly introduces some preferred embodiments. Simplifications or omissions may be made to avoid obscuring the purpose of the section. Such

from an exemplary RFID reader at different RF frequencies. FIG. 7 illustrates exemplary interactions between an exem

plary RFID reader and an exemplary RFID tag at various

60 exemplary frequencies that may be used by the exemplary RFID reader, where the RFID tag is stationary relative to the reader.

FIG. 8 is a time series of images of two exemplary RFID tags, one stationary relative to an exemplary RFID reader and

65 one in motion relative to the exemplary RFID reader. FIG. 9 shows two plots which reflect exemplary correla

tions or lack of correlations between received signal strength


US 7,619,524 B2 3

from an exemplary RFID tag and the frequency of a read from an exemplary RFID reader, based on the exemplary tags and exemplary reader of FIG. 8.

FIG.10 shows an exemplary environment where an exemplary RFID reader is being moved over some distance, and various exemplary RFID tags are present.

FIG.11 is a plot of the visibility overtime of the exemplary RFID tags of FIG. 10.

FIG. 12 is a flowchart of method to determine whether an RFID tag is moving coherently with an RFID reader.


In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will become obvious to those skilled in the art that the present invention may be practiced without these specific details. The description and representation herein are the common means used by those experienced or skilled in the art to most effectively convey the substance of their work to others skilled in the art. In other instances, well-known methods, procedures, components, and circuitry have not been described in detail to avoid unnecessarily obscuring aspects of the present invention.

References in the specification to "one embodiment," "an embodiment," "an example embodiment," etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. 1. Exemplary Operating Environment 2. Overview of Methods To Identify An RFID Tag Moving

Coherently With Reader 3. First Exemplary Method To Identify An RFID Tag Moving

Coherently With Reader 4. Second Exemplary Method To IdentifY An RFID Tag Mov

ing Coherently With Reader

4 reader 104 uses to initiate communication. Readers 104a and 104b may also communicate with each other in a reader network (see FIG. 2).

As shown in FIG. 1, reader 104a "reads" tags 120 by transmitting an interrogation signal110a to the population of tags 120. Interrogation signals may have signal carrier frequencies or may comprise a plurality of signals transmitted in a frequency hopping arrangement. Readers 104a and 104b typically operate in one or more of the frequency bands allot-

10 ted for this type of RF communication. For example, the Federal Communication Commission (FCC) defined frequency bands of 902-928 MHz and 2400-2483.5 MHz for certain RFID applications.

Tag population 120 may include tags 102 of various types, 15 such as, for example, various classes of tags as enumerated

above. Thus, in response to interrogation signals, the various tags 102 may transmit one or more response signals 112 to an interrogating reader 104. Some of the tags, for example, may respond by alternatively reflecting and absorbing portions of

20 signal 104 according to a time-based pattern or frequency. This technique for alternatively absorbing and reflecting signal104 is referred to herein as backscatter modulation. Typically, such backscatter modulation may include one or more alpha-numeric characters that uniquely identifY a particular

25 tag. Readers 104a and 104b receive and obtain data from response signals 112, such as an identification number of the responding tag 102. In the embodiments described herein, a reader may be capable of communicating with tags 102 according to various suitable communication protocols,

30 including Class 0, Class 1, EPC Gen 2, other binary traversal protocols and slotted aloha protocols, and any other protocols mentioned elsewhere herein, and future communication protocols. Additionally, tag population 120 may include one or more tags having the packed object format described herein

35 and/or one or more tags not using the packed object format (e.g., standard ISO tags).

FIG. 2 shows a block diagram of an example RFID reader 104. Reader 104 includes one or more antennas 202, a

40 receiver and transmitter portion 220 (also referred to as transceiver 220), a baseband processor 212, and a network interface 216. These components of reader 104 may include software, hardware, and/or firmware, or any combination thereof, for performing their functions.

5. Third Exemplary Method To Identify An RFID Tag Mov- 45

ing Coherently With Reader

Baseband processor 212 and network interface 216 are optionally present in reader 104. Baseband processor 212 may be present in reader 104, or may be located remote from reader 104. For example, in an embodiment, network interface 216 may be present in reader 104, to communicate

6. Fourth Exemplary Method To IdentifY An RFID Tag Moving Coherently With Reader

7. Conclusion

1. Exemplary Operating Environment Before describing embodiments of the inventions in detail,

it is helpful to describe an example RFID communications environment in which the inventions may be implemented. FIG. 1 illustrates an environment 100 where RFID tag readers 104 (readers 104a and 104b shown in FIG. 1) communicate with an exemplary population 120 ofRFD tags 102. As shown in FIG. 1, the population 120 of tags includes seven tags 1 02a-1 02g. A population 120 may include any number of tags 102.

Environment 100 includes any number of one or more readers 104. For example, environment 100 includes a first reader 104a and a second reader 104b. Readers 104a and/or 104b may be requested by an external application to address the population of tags 120. Alternatively, reader 104a and/or reader 104b may have internal logic that initiates communication, or may have a trigger mechanism that an operator of a

50 between transceiver portion 220 and a remote server that includes baseband processor 212. When baseband processor 212 is present in reader 104, network interface 216 may be optionally present to communicate between baseband processor 212 and a remote server. In another embodiment, network

55 interface 216 is not present in reader 104. In an embodiment, reader 104 includes network interface

216 to interface reader 104 with a communications network 218. As shown in FIG. 2, baseband processor 212 and network interface 216 communicate with each other via a com-

60 munication link 222. Network interface 216 is used to provide an interrogation request 210 to transceiver portion 220 (optionally through baseband processor 212), which may be received from a remote server coupled to communications network 218. Baseband processor 212 optionally processes

65 the data of interrogation request 210 prior to being sent to transceiver portion 220. Transceiver 220 transmits the interrogation request via antenna 202.


US 7,619,524 B2 5

Reader 104 has at least one antenna 202 for connnunicating with tags 102 and/or other readers 104. Antenna(s) 202 may be any type of reader antenna known to persons skilled in the relevant art(s ), including for example and without limitation, a vertical, dipole, loop, Yagi-Uda, slot, and patch antenna type.

Transceiver 220 receives a tag response via antenna 202.

6 The configuration of transceiver 220 shown in FIG. 2 is

provided for purposes of illustration, and is not intended to be limiting. Transceiver 220 may be configured in numerous ways to modulate, transmit, receive, and demodulate RFID connnunication signals, as would be known to persons skilled in the relevant art(s ).

The inventions described herein are applicable to any type of RFID tag. FIG. 3 is a schematic block diagram of an example radio frequency identification (RFID) tag 102. Tag

Transceiver 220 outputs a decoded data signal 214 generated from the tag response. Network interface 216 is used to transmit decoded data signal214 received from transceiver portion 220 (optionally through baseband processor 212) to a remote server coupled to communications network 218. Baseband processor 212 optionally processes the data of decoded data signal 214 prior to being sent over connnunications network 218.

10 102 includes a substrate 302, an antenna 304, and an integrated circuit (I C) 306. Antenna 304 is formed on a surface of substrate 302. Antenna 304 may include any number of one, two, or more separate antennas of any suitable antenna type, including for example dipole, loop, slot, and patch. IC 306

15 includes one or more integrated circuit chips/dies, and can include other electronic circuitry. IC 306 is attached to substrate 302, and is coupled to antenna 304. IC 306 may be attached to substrate 302 in a recessed and/or non-recessed location.

In embodiments, network interface 216 enables a wired and/or wireless connection with connnunications network 218. For example, network interface 216 may enable a wireless local area network (WLAN) link (including a IEEE 802.11 WLAN standard link), a BLUETOOTH link, and/or 20

other types of wireless connnunication links. Connnunications network 218 may be a local area network (LAN), a wide area network (WAN) (e.g., the Internet), and/or a personal area network (PAN).

In embodiments, a variety of mechanisms may be used to 25

initiate an interrogation request by reader 104. For example, an interrogation request may be initiated by a remote computer system/server that connnunicates with reader 104 over communications network 218. Alternatively, reader 104 may include a finger-trigger mechanism, a keyboard, a graphical 30

user interface (GUI), and/or a voice activated mechanism with which a user of reader 104 may interact to initiate an interrogation by reader 104.

In the example of FIG. 2, transceiver portion 220 includes a RF front-end 204, a demodulator/decoder 206, and a modu- 35

lator/encoder 208. These components of transceiver 220 may include software, hardware, and/or firmware, or any combination thereof, for performing their functions. Example description of these components is provided as follows.

Modulator/ encoder 208 receives interrogation request 210, 40

and is coupled to an input of RF front-end 204. Modulator/ encoder 208 encodes interrogation request 210 into a signal format, such as, for example, one of pulse-interval encoding (PIE), FMO, or Miller encoding formats, modulates the encoded signal, and outputs the modulated encoded interro- 45

gation signal to RF front-end 204. RF front-end 204 may include one or more antenna match

ing elements, amplifiers, filters, an echo-cancellation unit, a down-converter, and/or an up-converter. RF front-end 204 receives a modulated encoded interrogation signal from 50

modulator/encoder 208, up-converts (if necessary) the interrogation signal, and transmits the interrogation signal to antenna 202 to be radiated. Furthermore, RF front-end 204 receives a tag response signal through antenna 202 and downconverts (if necessary) the response signal to a frequency 55

range amenable to further signal processing. Demodulator/decoder 206 is coupled to an output of RF

front-end 204, receiving a modulated tag response signal from RF front-end 204. In an EPC Gen 2 protocol environment, for example, the received modulated tag response sig- 60

nal may have been modulated according to amplitude shift keying (ASK) or phase shift keying (PSK) modulation techniques. Demodulator/decoder 206 demodulates the tag response signal. For example, the tag response signal may include backscattered data formatted according to FMO or 65

Miller encoding formats in an EPC Gen 2 embodiment. Demodulator/decoder 206 outputs decoded data signal 214.

IC 306 controls operation of tag 102, and transmits signals to, and receives signals from RFID readers using antenna 304. In the example of FIG. 3, IC 306 includes a memory 308, a control logic 310, a charge pump 312, a demodulator 314, and a modulator 316. Inputs of charge pump 312, and demodula-tor 314, and an output of modulator 316 are coupled to antenna 304 by antenna signal 328.

Demodulator 314 demodulates a radio frequency connnunication signal (e.g., interrogation signal 110) on antenna signal 328 received from a reader by antenna 304. Control logic 310 receives demodulated data of the radio frequency connnunication signal from demodulator 314 on an input signal322. Control logic 310 controls the operation ofRFID tag 102, based on internal logic, the information received from demodulator 314, and the contents of memory 308. For example, control logic 310 accesses memory 308 via a bus 320 to determine whether tag 102 is to transmit a logical "1" or a logical "0" (of identification number 318) in response to a reader interrogation. Control logic 310 outputs data to be transmitted to a reader (e.g., response signal 112) onto an output signal 324. Control logic 310 may include software, firmware, and/or hardware, or any combination thereof. For example, control logic 310 may include digital circuitry, such as logic gates, and may be configured as a state machine in an embodiment.

Modulator 316 is coupled to antenna 304 by antenna signal 328, and receives output signal 324 from control logic 310. Modulator 316 modulates data of output signal324 (e.g., one or more bits of identification number 318) onto a radio fre-quency signal (e.g., a carrier signal transmitted by reader 104) received via antenna 304. The modulated radio frequency signal is response signal112 (see FIG. 1), which is received by reader 104. In one example embodiment, modulator 316 includes a switch, such as a single pole, single throw (SPST) switch. The switch is configured in such a marmer as to change the return loss of antenna 304. The return loss may be changed in any of a variety of ways. For example, the RF voltage at antenna 304 when the switch is in an "on" state may be set lower than the RF voltage at antenna 304 when the switch is in an "off' state by a predetermined percentage (e.g., 30 percent). This may be accomplished by any of a variety of methods known to persons skilled in the relevant art(s).

Charge pump 312 (or other type of power generation mod-ule) is coupled to antenna 304 by antenna signal328. Charge pump 312 receives a radio frequency connnunication signal (e.g., a carrier signal transmitted by reader 1 04) from antenna 304, and generates a direct current (DC) voltage level that is output on tag power signal326. Tag power signal326 powers circuits ofiC die 306, including control logic 320.

Charge pump 312 rectifies a portion of the power of the radio frequency communication signal of antenna signal 328


US 7,619,524 B2 7

to create a voltage power. Charge pump 312 increases the voltage level of the rectified power to a level sufficient to power circuits of IC die 306. Charge pump 312 may also include a regulator to stabilize the voltage of tag power signal 326. Charge pump 312 may be configured in any suitable way known to persons skilled in the relevant art( s ). For description

8 pictured, used for moving items within a warehouse. Vehicle 405 has associated with it an exemplary RFID reader 104 with RFID reader antenna 202.

of an example charge pump applicable to tag 102, refer to U.S. Pat. No. 6,734,797, titled "Identification tag Utilizing Charge Pumps for Voltage Supply Generation and Data Recovery," which is incorporated by reference herein in its 10

entirety. Alternative circuits for generating power in a tag, as would be known to persons skilled in the relevant art( s ), may

FIG. 4A shows three snapshots in time of the movement of vehicle 405 with RFID reader 104, specifically starting at time t0 , continuing through time t0 +P, and then continuing until time t0 +2P. It may be seen that over this period of time vehicle 405 moves a distance across warehouse 400, as seen by the progression of events from the lower part of FIG. 4A representing time t0 , to the middle part of FIG. 4A representing time t0 +P, to the top of FIG. 4A representing time t0 +2P.

Also shown in FIG. 4A is that vehicle 405 may be carrying an exemplary object, box, or container 410, and that exemplary container 410 may have associated with it anRFID Tag1

be present. Further description of charge pump 312 is provided below.

It will be recognized by persons skilled in the relevant art( s) that tag 102 may include any number of modulators, demodulators, charge pumps, and antennas. Tag 102 may additionally include further elements, including an impedance matching network and/or other circuitry. Furthermore, although tag 102

15 102a. Container 410 is resting securely on vehicle 405 and Tag1102a is attached to container 410. In this embodiment RFID reader 104 is attached to vehicle 405 and is stationary in relation to vehicle 405.

is shown in FIG. 3 as a passive tag, tag 102 may alternatively 20

be an active tag (e.g., powered by battery).

Because Tag1102 is affixed to container 410 and is being carried by vehicle 405, there is a fixed relative distance between antenna 202 of RFID reader 104 and Tag1 102a.

Memory 308 is typically a non-volatile memory, but can alternatively be a volatile memory, such as aD RAM. Memory 308 stores data, including an identification number 318. In a Gen-2 tag, tag memory 308 may be logically separated into 25

four memory banks.

That fixed distance is indicated by the line labeled Dl. It can be seen through the progression of drawings that even as vehicle 405 moves through environment 400, container 410, RFID reader 104, associated antenna 202 and Tag1102a all remain in a fixed relationship with the vehicle 405. Therefore,

2. Overview of Methods to Identify an RFID Tag Moving Coherently with Reader

The following sections of this specification, along with FIGS. 4 through 9, describe exemplary embodiments that incorporate the features of the inventions. The embodiment(s) described, and references in the specification to "exemplary embodiment", "one embodiment", "an embodiment", "an example embodiment", etc., indicate that the embodiment(s) described may include a particular procedure, operation, step, feature, structure, or characteristic, but every embodiment may not necessarily include the particular procedure, operation, step, feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular procedure, operation, step, feature, structure, or characteristic is described in connection with an embodiment, it is understood that it is within the knowledge of one skilled in the art to effect such procedure, operation, step, feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

One or more embodiments of the inventions are now described. While specific methods and configurations are discussed, it should be understood that this is done for illustration purposes only. A person skilled in the art will recognize that other configurations and procedures may be used without departing from the spirit and scope of the invention.

In particular, the inventions are described in the context of an environment where an RFID reader may be in motion while reading RFID tags which may or may not be in motion in relation to the RFID reader. Persons skilled in the relevant arts will recognize that the elements, methods, techniques, and principles of the inventions may be applied, with suitable modifications, to other kinds ofRF systems suitable for identifYing a radio frequency marker.

3. First Exemplary Method to Identify an RFID Tag Moving Coherently with Reader

over time, the distance D1 remains constant as long as container 410 is being carried by vehicle 405.

The time interval between each of the three views of the 30 vehicle 405 (and associated elements) shown in FIG. 4A is

denoted as time interval P. In this exemplary embodiment, RFID reader 104 will emit a signal at a given frequency f, and that frequency fhas a corresponding fundamental period Pfl as well as an associated wavelength A (discussed further

35 below). For ease of description the time interval P illustrated in FIG. 4A is some integer multiple of the fundamental period Pfl that is, P=n*Pfl where 'n' is an integer value. As will be discussed in detail below, Tag1102a, whose distance D1 from reader 104 remains fixed, when interrogated, should always

40 return a signal of approximately constant strength at those time intervals denoted by to, t0 +PI2, t0 +P, t0 +3P/2, t0 +2P, t0 +5P/2, t0 +3P, etc.

Also seen in exemplary environment 400 is a second Tag2 102b. Tag 2 102b is stationary within the environment 400.

45 For example, Tag2 102b may be attached to a box or some other product or storage unit within warehouse environment 400 which is currently stationary with respect to the facility. Therefore Tag2 1 02b remains stationary while vehicle 405 is in motion. Therefore, there is relative motion between vehicle

50 405 and Tag2102b. At time t0 , Tag2102b is at a distance D21

from antenna 202.Attimet0 +P, Tag2102b is at a distance D22

from antenna 202. Finally, at time t0 +2P, Tag2 102b is at distance D23 from antenna 202.

Also seen in exemplary environment 400 is a third tag, 55 Tag3 1 02c which is also in motion. However, Tag3 1 02c is in

motion independently of vehicle 405 (for example, a person may be carrying an object to which is attached Tag3 102c). Whatever the cause of motion ofTag3 102c, the result is that while Tag3 1 02c is in motion, it is unlikely to be in motion that

60 is synchronous or coherent with vehicle 405. Consequently, Tag3 102c is not in coherent motion with RFID reader 104; this can be seen from the varied distances between Tag3 1 02c and antenna 202 ofRFID reader 104. FIG. 4A illustrates an exemplary environment 400 which

may, for example, be a warehouse or other facility where an RFID reader 104 moves along with a piece of equipment or by 65

being carried/worn by an operator. Exemplary environment 400 may have, for example, a vehicle 405 such as the forklift

For example, at time t0 , Tag3 is at a distance D3, from antenna 202 ofRFID reader 104. At time t0 + P, Tag3 1 02c is at a distance D32 from antenna 202. Finally, at time t0 +2P, Tag3 102c is at a distance D33 from antenna 202.


US 7,619,524 B2 9

FIG. 4B examines the circumstances shown in FIG. 4a from another point of view. FIG. 4B shows an exemplary RF signal420 having a wavelength A that emanates from antenna 202 ofRFID reader 104, which is associated with exemplary vehicle 405. For purposes of illustration in FIG. 4B, Tag1 1 02a is placed at a particular distance from antenna 202. Tag1 1 02a is shown to be a distance of one and a half wavelengths (that is, 1.5*"A) from antenna 202. It will be understood by persons skilled in the relevant arts that this distance of one and a half wavelengths is purely for convenience in the illustra-

10 tent amounts of energy from RF signal420. Rather, as a result of their motion in relation to antenna 202, they receive inconsistent amounts of energy from RF signal 420. Similarly, observing the energies received by Tag2 102b or Tag3 1 02c at

5 times t0 +P/2 and t0 +3P/2, it may again be observed that the amounts of energy received respectively by each tag at these times (that is, times which are separated by multiples of the period P of RF signal 420) are not consistent amounts of energy. This is a reflection of the fact that these tags are in

10 non-coherent motion in relation to RFID reader 104. tion. This is unlike the case for Tag11 02a which was examined

Exemplary RF signal 420 has a maximum amplitude A. in detail in FIG. 4B, where at intervals of time equal to integer Tag1102a is at a fixed distance from antenna 202, and thus is multiples oftheperiodP ofRF wave 420, Tag1102a could be positioned at a particular phase of that RF signal 420. In the expected to receive a consistent amount of energy. example shown, at time tO, Tag1102a happens to be posi- 15 FIGS. SA and SB provide exemplary plots 500 and 550, tioned at a point where it is receiving a maximum amplitude respectively, of the energy returned by an RFID tag 102 to 425 from RF signal 420. Shown also in FIG. 4B is the transit RFID reader 104 in exemplary environment 400 and help to ofRF signal420 at a series of time slices, specifically times illustrate how an RFID tag moving coherently with a reader t0 +PI2, t0 +P, t0 +3P/2, and t0 +2P. can be easily identified.

At time t0 +P/2, RF wave 420 is exactly 180° out of phase 20 Exemplary plot 500 shows the RSSI values, or received with its position at time t0 . As a consequence, Tag1102a still energyvalues,from Tag1102a at various times shown in FIG. sees a maximum amplitude and would still at that time there- 4. In plot 500 it is shown that at successive time intervals fore return a maximum signal. Similarly (and noting again which are synchronous with the half period of the RF signal thatTag1102a does not move overtime in relation to antenna 420, and starting with timet

0, Tag1102a (labeled also as "T1"

202), at times t0 +P, t0 +3P/2 and t0 +2P, Tag1102a will see a 25 in plot 500) will consistently return an amount of energy maximum amplitude 425 of RF signal 420; consequently, which is at a maximum amplitude, here indicated by the letter Tag1102a will return a maximum signal at these times. This M. This is an indication that Tag1102a is moving coherently is therefore an indication that Tag1102a is moving synchro- with RFID reader 104. As explained above in conjunction nously or coherently with RFID reader 104 and its antenna with FIG. 4B, if at a time t0 , Tag1102a is located at a peak of 202. 30 RF signal420, then at time intervals ofP/2, P, 3P/2, 2P, etc.,

FIG. 4C is another view of environment 400, this time RF signal 420 will again present its peak amplitude to Tag1 focusing on Tag2102b and Tag3102c.Again, Tag2102b and 102a; therefore Tag1102a will return a maximum energy. Tag3 102c are shown in relation to RFID reader 104 and As is also shown in plot 500, at other times Tag1102a may reader antenna 202. (Note however that for reasons of space receive less energy and therefore return less energy, as indi-the distances between Tag2 102b and antenna 202, or the 35 cated by a lower RSSI value for the dotted, shaded markers for distance between Tag3 102c and antenna 202, are not neces- Tag1102a. However, as long as measurements are made at sarily drawn in proportion to the distances as they were por- intervals which reflect the half period P/2 of RF signal 420 trayed in FIG. 4A.) emitted by RFID reader 104, those measurements of the

What is consistent, however, between FIG. 4A and FIG. 4C received energy reading of Tag1 102a should have substan-is that both Tag2 102b and Tag3 102c are shown as being in 40 tially consistent value. motion over time relative to RFID reader 104 and RFID FIG. SB presents exemplary plot 550 showing the RSSI reader antenna 202. Once again, five time slices are pre- values or received energy values ,from Tags2 1 02b and Tags3 sen ted: to, to+ P/2, to+ P, to+3P/2, and to+2P. 1 02c of exemplary environment 400 as a function of the time.

Because of the relative motion between RFID Reader 104 Again, the time intervals shown are half intervals of the period and Tag 2 102b, Tag 2 102b will not always be at the same 45 p ofRF signal420, at successive times t

0, t

0+PI2, t

0+P, t

0+3P/

phase of an RF wave emitted by antenna 202. In the case of 2, and t0+2P. As can be clearly seen from the plot, there is no

Tag2 102b it can be seen that at a first time t0 , Tag2 102b is particular correlation or consistency between the energies located in relation to antenna 202 at a position wherein it actually received from Tag2 1 02b at these periodic time inter-receives a maximum amplitude 427' ofRF signal 420 At time vals; a similar lack of correlation or consistency is observed t0 +PTag2102b is seen to receive an amplitude of energy 427" 50 for the readings ofTag3 102c. This lack of consistency is a which is less than 427'. At time t0 +2P Tag2 102b is seen to be direct result of the fact that neither Tag2, 102b norTag3 102c, in a position relative to antenna 202, and in relation to RF are consistently at the same phase ofRF signal420. This lack signal 420, such that Tag2 102b receives only a very small of consistency may be taken as an indicator that both Tag2 amount of energy 427"'. Because Tag2 1 02b is not always at 1 02b and Tag3 1 02c are not moving coherently with RFID the same phase of radio wave 420 it does not consistently 55 reader 104. respond to RFID Reader 104 in the same manner. It can also be seen by looking at the location ofTag2 at times tO+P/2 and t0+3P/2 that Tag2 is at locations where it will receive amounts of energy which are less than the full amplitude of RF signal 420.

Similarly, it can be seen from inspection of FIG. 4C that Tag3, as it changes position at various times, also receives at these various times varying amounts ofRF energy 429', 429", 429"' from RF signal 420.

In sUllilllary, at periodic intervals such as t0 , t0 +P or t0 +2P, where the periods are integer multiples of the period P of RF signal 420, Tag2 102b and Tag3 102c do not receive consis-

4. Second Exemplary Method to Identify an RFID Tag Moving Coherently with Reader

Certain RFID tag arrangements utilize a frequency hop-60 ping scheme wherein the reader interrogation signal includes

discrete bursts of signal at different frequencies with in a band of frequencies. The discrete bursts can be transmitted according to a pattern or randomly. For example, UHF RFID readers in the United States are said to operate at 915 MHz, but may

65 actually operate in a range from 902 MHz to 928 MHz inclusive. They may frequency hop randomly, or in some predetermined sequence or pseudo random sequence, to frequen-


US 7,619,524 B2 11

c1es from 902 MHz to 928 MHz inclusive. FIG. 6 schematically represents an RFID reader 104 operating at three distinct frequencies: F1, F2, and F3.

12 receives a relatively weak signal from RFID reader 104. Therefore Tag1102a will be detected by RFID reader 104 at a relatively low received signal strength indicator ("RSSI").

When RFID reader 104 is operating at frequency F3, antenna 202 exhibits radiative pattern 650. With Tag1102a still in the same relative position in relation to antenna 202 (as a result of moving synchronously or coherently in relation to antenna 202 of reader 104, if antenna 202 is in motion), Tag1 is now within the zone of the large near primary lobe 662 of

Also shown schematically are representations of the antenna radiation patterns associated with the different frequencies. As is well known in the art, different frequencies can result in changes in the radiative pattern from an antenna, which is illustrated in FIG. 6. Three different exemplary radiative patterns are illustrated, exemplary radiative pattern 630 associated with frequency F1, exemplary radiative pattern 640 associated with frequency F2, and exemplary radiative pattern 650 associated with frequency F3.

10 radiative pattern 650. As a consequence Tag1 102a now receives a larger amount of energy from RFID reader 104, and therefore Tag1 102a returns a larger RSSI to RFID reader 104. For each of the three exemplary radiative frequency pat

terns 630, 640 and 650, two lobes of the radiation pattern are depicted. A primary lobe is depicted by two overlapping 15

radiative areas 662 and 664, where area 662 is a region of stronger radiative output and area 664 is a region of weaker radiative output. Also, shown is side lobe 666 which may have a different level of radiative strength than area 662 or 664. However, for convenience in the discussion which follows, it 20

may be assumed that side lobe 666 has a radiative power or strength which is the same as the power within radiative area 662.

It will be noted from FIG. 7 that as long as Tag1 102a maintains the same relative position in relation to RFID reader antenna 202, that any time RFID reader 104 operates at one of the established frequencies-for example, frequency F1, frequency F2, or frequency F3-Tag1102a will always fall within a same, respective region of the antenna pattern 630, 640, 650 corresponding respectively to the emitted frequency. Therefore, Tag1 102a will always return to RFID reader 104 a specific RSSI which will be correlated with a given frequency. For example, frequency F1 will have associated with it an RSSI of 0, frequency F2 will always have associated with it a relatively low RRSI value, and frequency Persons skilled in the relevant arts will recognize that

actual patterns of radiative power dispersal from antenna 202 may vary significantly from that shown, and will in general depend on the precise design of antenna 202 and other factors. Similarly, persons skilled in the relevant arts will recognize that the degree of variation between antenna patterns 630, 640, and 650 may have been exaggerated for illustrative purposes. Further, persons skilled in the relevant arts will recognize that the strength of the RF signal may vary continuously

25 F3 will always have associated with it a relatively high RRSI value.

Persons skilled in the relevant arts will recognize that in fact, due to multipath reflections and other environmental factors, the dispersal of radiation by antenna 202 may not

in space, rather than being segmented into regions of distinct strength with specific boundaries.

However, persons skilled in the relevant arts will recognize that a pattern of energy dispersal with varying strength in space does exist for an RF signal emitted from an antenna, and further that the pattern does typically vary with frequency in

30 always be precisely uniform for a given frequency. As a consequence, in real world operations the RSSI detected by RFID reader 104 may vary for a given frequency even ifTag1 1 02a retains the same fixed relative position in relation to antenna 202. However, such variations may be minimal; in addition, over a long term period of time, the RSSI values

35 returned by Tag1 may tend to cluster around a given value which may be associated with any given frequency of operation ofRFID reader 104.

a manner suggested by exemplary radiative patterns 630, 640, and 650, with regions of stronger radiation, weaker radiation, 40

and null zones.

FIG. 8 is a time series of images over six time intervals. RFID reader 104 is not shown in the figure, but is implied as being linked to RFID reader antenna 202 which is shown. The time series of six time periods shows three different frequen-cies being used, with each frequency being repeated twice during the time series, along with the associated radiative patterns already discussed above in conjunction with FIG. 6 and FIG. 7. RFID Tag1102a is also illustrated (now labeled "T1" for reasons of space on the drawing), as previously shown in FIG. 7, in a fixed relative position in relation to RFID reader antenna 202. As a consequence, and as already discussed in conjunction with FIG. 7, RFID Tag1102a will

FIG. 7 again depicts RFID reader 104 coupled to antenna 202. FIG. 7 also depicts an RFID tag labeled as Tag1102a. RFID reader 104 may be stationary or may be in motion. Tag1 102a is stationary relative to RFID reader 104, and in particu- 45

lar relative to RFID reader antenna 202. Therefore, if RFID reader 104 is in motion, then Tag1 102a is also in motion synchronously, or coherently, with RFID reader 104, such that Tag11 02a maintains the same relative position over time

50 show a substantially constant correlation between the detected RSSI ofTag1102a, as detected by reader 104, and the frequency which is being emitted by antenna 202 of reader 104.

in relation to antenna 202. FIG. 7 illustrates the interaction between RFID reader 104

with antenna 202, and Tag1102a, at the various frequencies that may be used by RFID reader 104.

For example, when RFID reader 104 is operating at frequency F1, and therefore antenna 202 is displaying radiative 55

pattern 630, Tag1102a may fall in a null region of radiative pattern 63 0. As a consequence Tag11 02a does not receive any energy from RFID reader 104. Therefore, as a further consequence, Tag1102a does not send a signal back to RFID reader 104; hence, during the period when RFID reader 104 is oper- 60

ating at frequency F1, Tag1102a is not detected. When RFID reader 104 is operating at frequency F2,

antenna 202 exhibits radiative pattern 640. With Tag1102a remaining in the same position relative to antenna 202 (as a result of moving synchronously or coherently in relation to 65

antenna 202 of reader 104, if antenna 202 is in motion), Tag1 102a falls within outer lobe 664 and therefore Tag1 102a

An additional element in FIG. 8 is a second RFID Tag2 102b (labeled as "T2"). Unlike Tag1102a, which is stationary relative to antenna 202 (or, equivalently is moving synchronously or coherently with antenna 202), RFID Tag2 1 02b is in motion relative to antenna 202. As a result, Tag2 102b does not maintain a predictable location in the antenna field pattern overtime.

For example, at time 1, RFID Tag2 102b is located within side lobe 666 of the antenna pattern, which for purpose of discussion may be assumed to have a strength approximately the same as inner primary lobe 662 of the radiation pattern 630.

At time 2, Tag2 102b has moved relative to antenna 202 such that Tag2 1 02b is now within the domain of inner primary lobe 662.


US 7,619,524 B2 13 14

At time 3 Tag2 102b is still within the domain of inner primary lobe 662. Therefore, at times 1, 2 and 3, Tag2 102b will be detected with a strong RSSI value. However, at these three times (namely time 1, time 2 and time 3), antenna 202 is radiating at three different frequencies, namely frequency F1, 5

frequency F2 and frequency F3. Therefore a particular RSSI value for Tag2 102b is not correlated with any particular frequency used by RFID reader 104.

RFID reader 104, may be applicable over relatively short distances, for example, distances on the order of several meters, as well as possibly for longer distances.

When an RFID reader may be moving over even larger distances, for example, across the span of a warehouse or other facility, an additional method may be available to supplement the method described above, and/or as an alternative to the method described above. The method entails analyzing the visibility ofanRFID tag 102 to reader 104 over This lack of correlation continues through times 4, 5 and 6.

For example, at time 4, which is associated with frequency 10

F2, Tag2 102b may be found in the region of outer primary lobe 664 and therefore may be expected to return a low RSSI which is associated with frequency F2.

a period of time. In general, the following criteria contribute to a positive determination that an RFID tag 102 is moving coherently with reader 104 over a period of time:

RFID tag 102 is visible to reader 104 during all, substantially all, or at least a majority of reads over the period of time;

At time 5, Tag2 102b is in a null region and therefore will return no energy at all to RFID reader 104.

At time 6 associated with frequency F3, Tag2 1 02b is again in outer primary lobe 664, and therefore will return a low RSSI value to RFID reader 104.

15

the reads for which RFID tag 102 is visible to reader 104 over the period of time are distributed uniformly or substantially uniformly over the period of time;

FIG. 9 shows two plots 910, 920 which are directly associated with the exemplary tag behavior illustrated in FIG. 8, 20

discussed immediately above.

the reads for which RFID tag 102 is visible to reader 104 over the period of time span the full period of time under consideration;

Plot 910 shows the relationship between: the received signal strength value, or RSSI, detected by

RFID reader 104 from Tag1102a; and

the reads for which RFID tag 102 are visible to RFID

the corresponding frequency of operation of RFID reader 25

104.

reader 104 over the period of time are consecutive reads, or are consecutive except for gaps attributed to RFID tag 102 being in a null zone of RFID reader 104 at some specific frequency or frequencies.

In particular, in plot 910 the RSSI values received from Tag1102a are plotted in relation to the frequency at which RFID reader 104 was operating at the time the RSSI values were detected. As can be seen on the plot, at both times when the RSSI value from Tag1102a was 0 (meaning Tag1102a was not detected at all), RFID reader 104 was operating at frequency Fl. As can also be seen in plot 910, on the two occasions when a low RRSI value was detected from Tag1 102a (represented as an RSSI value of 1), RFID reader 104 was operating at frequency F2. Finally, both times when a high RSSI value (indicated as RSSI value 2) was detected from Tag11 02a, RFID reader 104 was operating at frequency F3.

Therefore, it can be clearly seen from plot 910 that the 0 RSSI value for Tag1102a is correlated with frequency F1; the low RSSI value for Tag1102a is correlated with frequency F2; and the high RSSI value for Tag1102a is correlated with frequency F3. This correlation between the RSSI values for Tag1102a and the frequency at which RFID reader 104 is operating is taken to be an indicator that Tag11 02a is moving coherently with antenna 202 ofRFID reader 104.

Plot 920 shows the relationship between the detected RSSI values ofTag2102b as a function of the frequencies at which RFID reader 104 was operating at the time of detection of Tag2 1 02b. As can be seen from the plot, at frequency F1 Tag2 102b was detected with a high RSSI value of 2 on one occasion, but not detected at all on another occasion. At frequency F2, Tag2 102b was detected at both a low RSSI value and a high RSSI value. Similarly, at frequency F3, Tag2 102b was detected at both a low RSSI value and a high RSSI value. There is a clear lack of correlation between the detected RSSI values from Tag2 and the frequencies. This lack of correlation is interpreted as the reader and the tag not moving synchronously, which is consistent with the exemplary tag behavior exhibited in FIG. 8 above.

5. Third Exemplary Method to Identify an RFID Tag Moving Coherently with Reader

FIG. 10 illustrates an exemplary environment 1000 which may, for example, be a warehouse or other facility where an RFID reader 104 is being moved over some distance. For

30 example, in a warehouse facility, a forklift or other conveyance may be used to pick up items stored in the warehouse, the forklift may have an onboard RFID reader 104, while items picked up may have onboard RFID tags 102.

Dotted line 1020 in FIG. 10 shows an exemplary approxi-35 mate path 1020 which may be traveled by a hypothetical

conveyance in a warehouse facility. RFID reader antenna 202 is shown in the figure at a succession of times, specifically time equals 1 through time equals 7. (In FIG. 10, the forklift or other conveyance is not shown. RFID reader 104, which is

40 attached to antenna 202, is only shown at one point on the diagram, for Time 1, and is left implied elsewhere, i.e., at other times, to avoid visual clutter. Also, note that in FIG. 10, the antenna patterns are alternately either solid black or shaded gray; this too is for ease of viewing only, to help

45 visually distinguish time-adjacent but overlapping antenna patterns, and has no other significance.)

Also, shown in the diagram is RFID Tag1102a; a collectionofotherRFIDtags 102xwhicharelabeled T2, T3, T4, T5, T6, T7, T8 and T9102x; and two additional tags, Ta 102y and

50 T~ 102z. Tags T2-T9 102x are understood to be stationary in the

warehouse facility, while Tag1102a is understood to be carried on the same conveyance (such as a forklift) which carries RFID reader 104 and RFID reader antenna 202. Tags Ta 1 02y

55 and T~ 1 02z are understood to be in motion over the period of time, but independently of the motion ofRFID reader 104 (for example, they are not carried on the same forklift as RFID reader 104).

At progressive times Time=! through Time=7, it can be 60 seen in FIG. 10 that Tag1102a maintains the same relative

position in relation to RFID reader antenna 202; therefore Tag1 102a will be visible to RFID reader 104 at many or substantially all of the observation times from Time=! through Time=7.

The method just described with respect to FIGS. 4 through 65

7 above, for determining if an RFID tag 102 is moving synchronously or not moving synchronously with respect to an

It can be equally seen from FIG. 10 that T2 through T9 102x will only sometimes fall within the radiative antenna pattern 630, 640, 650 of RFID reader 104 and associated


US 7,619,524 B2 15 16

antenna 202. Specifically, since tags T2 through T9 102x are stationary, they will only be seen by RFID reader 104 when reader 104, in the course of its travels, happens to come within range of tags T2 through T9102x. Therefore, each tag of tags T2 through T9 102x will only be visible to reader 104 for a 5

limited subset of times 1 through 7.

6. Fourth Exemplary Method to Identify an RFID Tag Moving Coherently with Reader

FIG. 12 is a flow chart 1200 of a method to identifY an RFID tag 102 moving coherently with a reader 104. The method combines elements of the methods already discussed above.

The method begins with initialization at step 1210. Tags Ta 102y and T~ 102zare shown as being in motion in

FIG. 10, but their motion is independent of the motion 1020 of RFID reader 104. Therefore, they may coincidentally come within range of RFID reader 104, but they are unlikely to provide the consistent readings that are provided by tag T1 102a which is in coherent motion with RFID reader 104.

The visibility of the tags 102a, 102x, 102y, and 102z, as seen by RFID reader 104 in motion, is reflected in plot 1100 of FIG. 11, which is based on the exemplary scenario presented in FIG. 10. In plot 1100 it can be seen that Tag1102a is visible to RFID reader 104 at times 2, 3, 4, 5 and 7, which substantially spans the entire time frame that the conveyance is moving along path 102x. Moreover, the distribution of reads during which Tag1 102a is visible is distributed substantially uniformly over the period of time. Therefore, it is likely that tag T1102a is moving along with the conveyance and the associated RFID reader 104.

It can be seen on plot 1100 that remaining tags T2 through T9 102x are only visible for a short subset of times 1 through time 7. For example, T2 is visible only at times 1 and 2, while T9 is only visible at times 6 and 7. Therefore, according to the present method, it is inferred that tags T2 through T9 1 02x are not moving with the RFID reader.

Tag Ta 102y is read by RFID reader 104 at consecutive times 1, 2, 3, and 4. This may suggest that Ta 102y is in coherent motion with RFID reader 104a; however, since RFID tag Ta 1 02y is only visible for approximately half of the reads, this may suggest that Ta 1 02y is not moving coherently with RFID reader 104.

At step 1215, an RFID reader 104 begins transmitting read signals at a frequency or a variety of frequencies within a

10 band, where if multiple frequencies are used then the frequencies are repeated over time in a designated order, or a random or pseudorandom fashion.

In step 1220, the RFID reader 104 receives signals back from any RFID tags 102 within range. In step 1225, RFID reader 104, or a processor, computer, or server associated

15 with the reader 104, stores pertinent data. The pertinent data includes the IDs ofRFID tag 102s which send back signals, the times the signals are received for each tag 102, and an indication of the signal strength (such as the RSSI) of each received signal at each time for each tag 102. The pertinent

20 data may also include the wavelength or frequency of the signal.

The method can then branch in three directions, any of which may be performed independently, or which made be done first one then another (and in any order), or some com-

25 bination of which may be performed in parallel. A first branch continues with step 1240 where, for a given

tag 102, and for a given signal frequency or wavelength, and over a period of time, a calculation is made to determine a degree of consistency of the received signal strength for the

30 tag 102 at time intervals equal to the period of the signal.

The first branch continues with step 1245 where, based on the degree of consistency determined in step 1240, a determination is made as to the likelihood that a given RFID tag 102 is moving coherently with the RFID reader 104.

The first branch then either stops at step 1280, or continues 35 with step 1270, discussed further below.

A second branch continues with step 1250 where, for a given tag 102, and over a period of time, a calculation is made to determine a degree of correlation between the received signal strength for the tag 102, and the frequencies at which

40 the signal strengths were received.

Persons skilled in the relevant arts will recognize that detailed coherency algorithms may be implemented which may weight various factors, such as the percentage of time tag 102 is visible, the uniformity of distribution of reads of tag 102, and the degree to which the reads of tag 102 are consecutive. Further, algorithms may be implemented which take into account known operating parameters of particular environments. For example, in the case of exemplary environment

45 1000 of FIG. 10, it may be known (due to the specific nature

The second branch continues with step 1255 where, based on the degree of correlation determined in step 1250, a determination is made as to the likelihood that a given RFID tag 102 is moving coherently with the RFID reader 104.

The second branch then either stops at step 1280, or continues with step 1270, discussed further below.

of operations in the facility), that once a forklift picks up an item, the item will remain on the forklift until the forklift has ceased motion. In that case, an RFID tag such as exemplary tag Ta 102y, which is seen for only the first half of the reads (i.e., at times 1 through 4), may be determined to not be moving with the RFID reader 104 associated with the forklift.

Finally, tag T~ 102z is seen by RFID reader 104 at times 2, 5, and 7. These readings approximately span the full time span under consideration, and moreover are distributed approximately uniformly. However, because they represent less than half of the readings, and further because of the significant gaps between reads, an algorithm which analyzes tag T~ 102z may conclude that the tag is not moving coherently with RFID reader 104.

As noted above, the method of analyzing the appearances

Continuing from step 1225, the third branch continues with step 1260. In step 1260, the received data is analyzed to determine, for a given tag 102 and over a period of time, a

50 plurality of factors, which may include: (1) the percentage of time the tag 102 was seen over the period of time; (2) the uniformity of the distribution of reads for the tag 102 over the period of time; (3) the degree that reads were consecutive over the period of time; and ( 4) the degree to which the reads span the full period of time.

55 The third branch continues with step 1265 where, based on the factors analyzed in step 1260, a determination is made as to the likelihood that a given RFID tag 102 is moving coherently with the RFID reader 104.

The third branch then either stops at step 1280, or continues 60 with step 1270. In step 1270, the determinations made in steps

1045, 1255, and 1265 are combined to give a determination which may be more complete as to the likelihood that a given tag 102 is moving coherently with the reader 104. The method

of an RFID tag over a period of time may be used in conjunction with the method of correlating the strength of RFID tag readings with RFID reader frequencies; the combination of both methods is likely to provide a more reliable indicator of 65

whether or not an RFID tag 102 is moving synchronously with an RFID reader 104.

then stops at step 1280. The above description provides one embodiment of the

method. Alternative embodiments are possible within the scope and spirit of the present invention. In particular, in the


US 7,619,524 B2 17

embodiment described immediately above, steps 1240 and 1245 are described as one data processing path, steps 1250 and 1255 are described as another data processing path, and steps 1260 and 1265 are described as yet another alternative and/ or parallel data processing path. In an alternative embodi- 5

ment of a method to determine whether an RFID tag 102 is moving coherently with an RFID reader 104, calculations may be performed which combine in one path or one calculation process elements of steps 1240, 1245, 1250, 1255, 1260, and 1265, to arrive at the desired determination. 10

7. CONCLUSION

The above examples of a system and method for determining if an RFID tag is moving with an RFID reader are exem- 15 plary only. Persons skilled in the relevant arts will recognize that a variety of threshold parameters may be set in establishing such a method and a variety of algorithms used to determine degrees of correlation between detection of RFID tags and associated parameters, such as time or frequency. Such

20 variations fall within the scope and spirit of the present invention which is not limited by the particular examples described above.

While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. It 25

will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodi- 30

ments, but should be defined only in accordance with the following claims and their equivalents.

What is claimed is: 1. A method for identifYing an RFID tag moving with an

RFID reader, comprising: (a) transmitting by the reader over a period of time a plu

rality of reading signals, wherein said signals have a signal period;

(b) receiving by the reader reply signals from any RFID tags within range of the reader;

(c) determining for each reply: a particular RFID tag from which the reply was received;

and a received signal strength from the RFID tag;

35

40

18 6. The method of claim 5, further comprising that if over

the plurality of reads the degree of consistency exceeds a designated consistency threshold, then the RFID tag is moving coherently with the RFID reader.

7. The method of claim 1, further comprising: (f) determining over the period of time a distribution of

reading signals for which the particular RFID tag is RF visible to the reader;

(f) determining based on the distribution a probability that the particular RFID tag was in range of the reader from the beginning of the period of time to the end of the period of time; and

(g) determining whether the particular RFID tag is moving coherently with the RFID reader based on both the consistencies and the probability.

8. The method of claim 1, further comprising: (f) determining a degree of correlation between received

signal strengths and a plurality of respective frequencies of the read signals; and

(g) determining whether the particular RFID tag is moving coherently with the RFID reader based on both the consistencies and the correlation.

9. A method for identifYing an RFID tag moving with an RFID reader, comprising:

(a) transmitting by the reader over a period of time a plurality of reading signals at a plurality of frequencies within a transmission band;


(c) determining for each reply: a particular RFID tag from which the reply was received; a received signal strength from the RFID tag; and a frequency associated therewith;

(d) analyzing the received signal strengths and noting any correlations of signal strengths with particular RFID tags and particular frequencies; and

(e) determining from the correlations whether the particular RFID tag is moving coherently with the RFID reader.

10. A method according to claim 9, further comprising determining whether the particular RFID tag consistently does not reply at a particular frequency.

11. The method of claim 9, wherein step (d) comprises determining for a first read of the particular tag at a particular

(d) analyzing the received signal strengths and noting any consistencies of signal strengths correlated with the period of the signal period; and

(e) determining from the consistencies whether the particular RFID tag is moving coherently with the RFID reader.

45 frequency and a second read of the particular tag at the particular frequency the degree to which the signal strength is the same or substantially the same for the first read and the second read.

2. A method according to claim 1, further comprising deter-50

mining whether the particular RFID tag consistently does not reply on a period basis which has the same period as the signal period.

3. The method of claim 1, wherein step (d) comprises: identifYing a first read of the particular tag at a first time and

a second read of the particular tag at a second time, 55

wherein a time interval between the first read and the second read is an integer multiple of the signal period; and

12. The method of claim 9, wherein noting any correlations of signal strengths with particular RFID tags and particular frequencies comprises at least one of:

determining a degree to which the particular RFID tag consistently does not reply at a particular frequency; and

determining a degree to which the particular RFID tag consistently returns a substantially consistent signal strength at a particular frequency;

wherein is determined a degree of correlation between the particular RFID tag and at least a frequency.

13. The method of claim 12, further comprising determin-determining a degree to which the signal strength is substantially the same for the first read and the second read.

4. The method of claim 3, further comprising repeating the identifying step and the determining step for a plurality of pairs of first reads at first times and respective second reads at respective second times.

60 ing that if over the plurality of reading signals the correlation between the particular RFID tag and the at least a frequency exceeds a designated correlation threshold, then the RFID tag is moving coherently with the RFID reader.

5. The method of claim 4, further comprising determining an aggregate level of consistency of signal strengths over a plurality of reads.

14. The method of claim 13, further comprising determin-65 ing that if over a plurality of frequencies the degree of corre

lation exceeds the designated correlation threshold, then the RFID tag is moving coherently with the RFID reader.


US 7,619,524 B2 19

15. A method for identifying an RFID tag moving with an RFID reader, comprising:

(a) transmitting by the reader over a period of time a plurality of reading signals at a plurality of frequencies within a transmission band;


(c) determining over the plurality of reading signals a distribution of reading signals for which a specific RFID tag is within range of the reader; and

(d) determining based on the distribution whether the particular RFID tag is moving coherently with the RFID reader.


10

20 an RF receiver associated with said RFID reader, wherein

said RFID receiver is configured to receive reply signals from any RFID tags within range of the reader;

a processor associated with said RFID reader, wherein said processor is configured to determine at least one of: any consistencies of a received signal strength from a

particular RFID tag correlated with a period of the plurality of reading signals;

a correlation between a signal strength received from the particular RFID tag and a particular frequency of the plurality of reading signals; and

a distribution of reading signals for which the particular RFID tag is within range of the reader.

20. The system of claim 19, further comprising a signal strength measuring component associated with said RFID reader, said signal strength measuring component configured to determine the signal strength received from the particular RFID tag.

determining a percentage of the period of time when the 15

particular RFID tag is in range of the reader; and determining based on the percentage and the distribution

whether the particular RFID tag is moving coherently with the RFID reader. 21. The system of claim 20, wherein said processor is

20 further configured to determine whether the particular RFID tag is moving coherently with the RFID reader based on at least one of:

17. The method of claim 15, further comprising: determining a degree to which the distribution is a substan

tially uniform distribution; and determining based on the degree to which the distribution

is a substantially uniform distribution whether the particular RFID tag is moving coherently with the RFID 25

reader. 18. The method of claim 15, further comprising: determining a particular frequency of the plurality of fre

quencies at which the particular RFID tag consistently does not reply at the particular frequency; and

decreasing a weighting of reading signals at said particular frequency when determining the distribution.

19. A system for identifying an RFID tag moving with an RFID reader, comprising:

30

the RFID reader, wherein said RFID reader is configured to 35

transmit over a period of time a plurality of reading signals;

the consistencies of the received signal strength from the particular RFID tag correlated with a period of the plurality of reading signals;

the correlation between the signal strength received from the particular RFID tag and the particular frequency of the plurality of reading signals; and

the distribution of reading signals for which the particular RFID tag is within range of the reader.

22. The system of claim 21, wherein said processor is further configured to determine whether the particular RFID tag is moving coherently with the RFID reader based on at least one of a plurality of consistencies and a plurality of correlations.

* * * * *


opatent.com · 2019. 5. 30. · steven c. oppenheimer, esq. patent attorney (pto reg. # 57,418, md...

Documents