Method and apparatus for testing optical films

1. A system for testing a film, the system comprising:

a Lambertian light source, the Lambertian light source comprising a mixing chamber having an input port and an output port;

a light emitter coupled to the input port;

an integrating sphere having an input port;

at least one baffle disposed in one of the mixing chamber and the integrating sphere; and

a measuring device for producing a measurement;

wherein during testing the film is positioned between the output port of the mixing chamber and the input port of the integrating sphere,

wherein the measuring device is optically coupled to the integrating sphere,

wherein a property of a portion of the film is altered in response to the measurement.

2. The system of claim 1 wherein the film comprises light scattering particles.

3. The system of claim 2 wherein the light scattering particles comprise TiOx particles.

4. The system of claim 1 wherein the film comprises luminescent materials.

5. The system of claim 4 wherein the luminescent materials comprise phosphors.

6. The system of claim 1 wherein the output port of the mixing chamber is spaced less than 500μ from the film.

7. The system of claim 1 wherein the output port of the mixing chamber is spaced less than 1 mm from the input port of the integrating sphere.

8. The system of claim 1 wherein during testing the film is in sliding engagement with at least one of the input port of the integrating sphere and the output port of the mixing chamber.

9. The system of claim 1 wherein the measuring device is, one of a spectrometer and a photo colorimeter.

10. A structure for testing an optical film, the structure comprising:

a first tester, the first tester comprising:

a Lambertian light source, the Lambertian light source comprising a mixing chamber having an input port and an output port;

a light emitter coupled to the input port;

an integrating sphere having an input port;

at least one baffle disposed in one of the mixing chamber and the integrating sphere; and

a measuring device; and

a second tester disposed downstream relative to the optical film of the first tester,

wherein during testing the optical film is positioned between the output port of the mixing chamber and the input port of the integrating sphere;

wherein the measuring device is optically coupled to the integrating sphere

wherein the second tester measures a property of the optical film

wherein the optical film comprises light scattering particles.

11. The structure of claim 10 wherein the light emitter is an LED configured to emit white light.

12. The structure of claim 10 wherein the measuring device is one of a spectrometer and a photo colorimeter.

13. The structure of claim 10 wherein during testing, the output port of the mixing chamber is spaced less than 500 μm from the optical film.

14. The structure of claim 10 wherein during testing, the output port of the mixing chamber is spaced less than 1 mm from the input port of the integrating sphere.

15. The structure of claim 10 wherein during testing the optical film is in sliding engagement with at least one of the input port of the integrating sphere and the output port of the mixing chamber.

16. The structure of claim 10 wherein at least one of the input port of the integrating sphere and the output port of the mixing chamber is a knife-edge port.

17. The structure of claim 10 wherein the luminescent film comprises phosphor disposed in an optical material.

18. A method comprising:

positioning a Lambertian light source proximate a first surface of a optical film;

positioning an opening in an integrating sphere proximate a second surface of the optical film;

illuminating a portion of the optical film with the Lambertian light source;

measuring a property of light from the optical film collected by the integrating sphere; and

after measuring a property of light from the optical film, altering a property of a portion of the optical film in response to the measurement

wherein the optical film comprises light scattering particles.

19. The method of claim 18 wherein the light from the optical film comprises light from the Lambertian light source transmitted through the optical film at the same wavelength and light from the Lambertian light source absorbed by the optical film and emitted by the optical film at a different wavelength.

20. The method of claim 18 wherein the scattering particles comprise TiO x .