OPTICAL DESIGN & MEASUREMENT TOOLS

LIGHT TECLIGHT TEC

OPTICAL DESIGN & MEASUREMENT TOOLS

LIGHT TECLIGHT TEC

For 2D/3D scattered light measurements.A compact camera based optical system for scattering characterization of any kind of material.

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OPTICAL DESIGN & MEASUREMENT TOOLS

LIGHT TECLIGHT TECBRDF

M i n i - D i f f 3D ( hemispheric) Scatterometer

B R D F / B T D F

D E S C R I P T I O N Mini-Diff is a compact optical system for scattering characterization of any kind of materials and objects. It allows, in a fast and easy way, to measure luminous energy distribution, and consequently characterizes surfaces of your examined regions such as roughness, defects, as well as types of coatings or paintings…Moreover, the system measures BRDF/BTDF which perfectly represents the way any surface scatters incoming light in 3D space. The incident light is provided by 4 collimated LEDs set up at 0°, 20°,40° and 60° incident angles for Reflective measurements and 1 collimated LED (0°) for Transmissive measurements. The hemi spherical scattered intensity is imaged at once on a camera.The instrument is calibrated before the measurement pointing to a calibration plate (black/white) supplied with the instrument. The calibration steps take less than 30 seconds and the measurement is then done in 10 seconds.The results (scattered intensity and BRDF/BTDF) can be saved to text formats, or can be exported to optical software format.

A P P L I C A T I O N S • Reflector material characterization for luminaires design

• Reflector/Diffuser material characterization for automotive design

• Photorealistic rendering: accurate measurement of diffusing behavior

• Cosmetics characteristics

• Roughness controls in production

• LCD Backlighting: BEF, DBEF inspection

Patent Pending : FR1250886

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OPTICAL DESIGN & MEASUREMENT TOOLS LIGHT TEC LIGHT TEC

E x a m p l e : R e f l e c t o r A l a n o d M i r o 5Reflector material can have quite complex behaviour depending on the of incidence plane. MINI-DIFF allows to capture scattering for angles of incidence parallel and perpendicular to stripes (anisotropic material).

Parallel

Perpendicular

Angle of incidence

R e f l e c t i v eM a t e r i a l sMini-Diff allows a quick measurement of the BRDF for 4 incident angles (0°, 20°, 40°, 60°). ✓ After a 2-step calibration (one step with a black standard to cancel the stray light and one step with a Lambertian standard to calibrate the response of the camera), it is possible to measure:

• Reflectors• Paints • Diffusing material • Sockets• Optical mounts

✓ The measured scattered intensity can be saved to text files, slices files, mesh format, BSDF format, ABg (Harvey Shack) fit and Gaussian/Lambertian fit.✓ The TIS measurements (Total Intensity Scattered) is calculated by the Mini-Diff software. This feature allows for example to compare directly the efficiency of the diffusers.✓ Mini-Diff software allows also to take into account anisotropic material and to generate directly the right file for illumination software.

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OPTICAL DESIGN & MEASUREMENT TOOLS LIGHT TEC LIGHT TEC OPTICAL DESIGN & MEASUREMENT TOOLS

LIGHT TECLIGHT TEC

T r a n s m i s s i v e M a t e r i a l s✓ Mini-Diff allows a quick measurement of the BTDF for one incident angle ( 0°).

✓ One special “transmission module” is supplied with the Mini-Diff. It includes red source accurately collimated on a large area in order to be insensitive to the sample placement.

✓ After a 1-step calibration using one Lambertian transmissive standard (supplied), it is possible to measure diffusing materials:

• Opal glass• Diffusing plastics• BEF (Brightness Enhanced Film)• Beam Shaper (Diffractive optics)

✓ The measured scattered intensity can be saved to text files, slices files, mesh format, BSDF format, ABg fit and Gaussian/Lambertian fit.

✓ The TIS measurements (Total Intensity Scattered) is calculated by the Mini-Diff software

✓ Algorithms can then be calculated? BTDF for more angles

Example : Luminit Diffuser

R e f l e c t i v e a n d T r a n s m i s s i v e M a t e r i a l sMini-Diff allows to measure BRDF and BTDF on one diffuser (front and back side measurement) and then it can build a BSDF file ready to use in illumination software.

OPTICAL DESIGN & MEASUREMENT TOOLS

LIGHT TECLIGHT TEC

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OPTICAL DESIGN & MEASUREMENT TOOLS

LIGHT TECLIGHT TEC

BTDF

Espace Alexandra • 359 rue Saint Joseph 83400 Hyères • FranceTel : +33 (0) 494 121 848Fax : +33 (0) 494 121 849E mail : sales@lighttec.fr • web : www.lighttec.fr

Mini-Diff in its suitcase

C a l i b r a t i o n a n d a c c u r a c yMini-Diff is supplied with 3 calibration standard samples:

• One Black standard• One Reflective Lambertian Standard• One Transmissive Lambertian Standard

Example of one measurement with one Spectralon sample (Lambertian standard): this shows measurements accuracy of +/- 3.5%The Mini-Diff software includes extrapolation of the BSDF up to 180°.

Exportation • Text file (ASTM format)• BSDF format (imported in commercial software) • Mesh file (rough camera data, 1000*1000 pixels)• Slice files (IES type) • Fit to Gaussian / Lambertian format • Fit to ABg, Harvey Shack format

Results • Dynamic Range: 10e 5 • Angular resolution 1°• Accuracy: < 4%• Repeatability < 2%

Sources • Red illumination (630 nm) • Collimated beam <1°• For reflection measurements, 4 Incident angles: 0°, 20°, 40°, 60°.• For transmission measurements, 1 Incident angle: 0°

Spot size on the sample surface • 2mm diameter

Field of view • + /-75°

T E C H N I C A L S P E C I F I C AT I O N S

* these specifications are not contractual and can be changed without notice

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