Download - Touchscreen 29
-
7/31/2019 Touchscreen 29
1/19
Submitted By :-Md Nazish Aslam
0832EC071029
Submitted To :-Mr. Amit Malik
DEPARTMENT OF ELECTRONICS & COMMUNICATION
SEMINAR
ON
TOUCHSCREEN TECHNOLOGY
-
7/31/2019 Touchscreen 29
2/19
INTRODUCING THE TECHNOLOGY
HOW DOES A TOUCHSCREEN WORK?
TOUCH SCREEN DIVERSITY
COMPARISON
APPLICATIONS
CONCLUSION
-
7/31/2019 Touchscreen 29
3/19
3
A visual display unit screen that allows the user to givecommands to the computer by touching parts of the screeninstead of using the keyboard or a mouse.
The display screen has a sensitive glass overlay placed on itand we could give the desired input by touching it.
A touch screen is based on CRT (Cathode Ray Tube)technology, that accepts direct onscreen input.
-
7/31/2019 Touchscreen 29
4/19
A basic touchscreen has three main components:1 Touch sensor;
2 Controller;
3 Software driver.
The touchscreen is an input device, so it needs to becombined with a display and a PC or other device to make acomplete touch input system.
-
7/31/2019 Touchscreen 29
5/19
5
A touch screen sensor is a clearglass panel with a touchresponsive surface which isplaced over a display screen sothat the responsive area of thepanel covers the viewable areaof the display screen.
-
7/31/2019 Touchscreen 29
6/19
6
The controller is asmall PC card thatconnects between the
touch sensor and thePC. It takesinformation from thetouch sensor andtranslates it intoinformation that PCcan understand.
-
7/31/2019 Touchscreen 29
7/19
7
The driver is a software that allows the touchscreen and computer to work together. It tells theoperating system how to interpret the touch event
information that is sent from the controller.
Most touch screen drivers today are a mouse-emulation type driver. This makes touching the
screen the same as clicking your mouse at the samelocation on the screen.
-
7/31/2019 Touchscreen 29
8/19
8
Resistive Touch screen
Capacitive Touch screen
*Surface capacitive
*Projected capacitiveSurface Acoustic wave (SAW) Touch screen
Near Field Imaging Touch screen
Infrared Touch screen
-
7/31/2019 Touchscreen 29
9/19
Resistive touch screen monitor iscomposed of a flexible top layerand a rigid bottom layer separatedby insulating dots, attached to atouch screen controller.
The inside surface of each of thetwo layers is coated with atransparent metal oxide coating
Pressing the flexible top sheetcreates electrical contact betweenthe resistive layers, producing a
switch closing in the circuit. The controller gets the alternating
voltages between the two layersand converts them into the digital
X and Y coordinates of theactivated area.
-
7/31/2019 Touchscreen 29
10/19
-
7/31/2019 Touchscreen 29
11/19
(Reading a 4-Wire Screen)
-
7/31/2019 Touchscreen 29
12/19
StructureSurface capacitive technology consists of auniform conductive coating on a glass panel.
Electrodes around the panels edge evenlydistribute a low voltage across the conductivelayer, creating a uniform electric field.
-
7/31/2019 Touchscreen 29
13/19
Working principleA human body is an electric conductor, so when you touch the screen witha finger, a slight amount of current is drawn, creating a voltage drop. Thecurrent respectively drifts to the electrodes on the four corners.Theoretically, the amount of current that drifts through the four electrodesshould be proportional to the distance from the touch point to the fourcorners. The controller precisely calculates the proportion of the currentpassed through the four electrodes and figures out the X/Y coordinate of atouch point.
-
7/31/2019 Touchscreen 29
14/19
Infrared (IR) technology relies on theinterruption of an IR light grid infront of the display screen. The touchframe contains a row of IR-lightemitting diode (LEDs) and photo
transistors, each mounted on twoopposite sides to create a grid ofinvisible infrared light.The IR controller sequentially pulsesthe LEDs to create a grid of IR lightbeams. When a stylus, such as a finger,
enters the grid, it obstructs the beams.One or more photo transistors fromeach axis detect the absence of lightand transmit signals that identifiesthe x and y coordinates.
-
7/31/2019 Touchscreen 29
15/19
Technology Capacitive SAW Infrared ResistiveTransparence Very good >92% Very good >92% Very good >92% 75%~85%Resolution Good Good Limited due to
spacing of IR
sensorsgood
Surface
Contaminants/durability
Resistant to
moisture andother surface
contaminants
Adversely
affected bymoisture or
Surface
contaminants
Potential for
False activationor dead zones
From Surface
Contaminants
Unaffected by
Surfacecontaminants.
Polyester top
sheet is easily
scratchedSensor substrate Glass with ITO
coating Glass with ITO
coating Any substrate Polyester top
sheet, glasssubstrate with
ITO coatingDisplay size 8.4"-21" 10.4"-30" 10.4"-60" up to 19"Touch method Human touch finger, gloved
hand or soft tipCan use any
pointing device Can use anypointing device
Comparison
-
7/31/2019 Touchscreen 29
16/19
The user must sit within arms reach of the display
Possible arm fatigue
Difficult to select small items
Possible retrofit problem (the touch screen must be fitted
on the screen)
Limitations:
-
7/31/2019 Touchscreen 29
17/19
17
Public Information Displays:::Tourism displays, Trade show display
Customer Self-Services:::
Stores, Restaurants, ATMs, Airline ticketterminals and Transportation hubs.
More uses...
Digital jukeboxes, Computerized gaming,Student Registration systems, Multimediasoftwares , Scientific applications etc.
-
7/31/2019 Touchscreen 29
18/19
18
Though the touch screen technology containssome limitations its very user friendly, fast,accurate, easy for the novices & fun to operate.It has been widely accepted. And now by justmodifying a little it can replace the mouse andkey board completely in near future.
-
7/31/2019 Touchscreen 29
19/19
Any queries???