Method and apparatus for testing luminescent films

1. A structure for testing a luminescent 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 luminescent film of the first tester,

wherein during testing the luminescent 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 luminescent film.

2. The structure of claim 1 wherein during testing, the output port of the mixing chamber is spaced less than 500 μm from the luminescent film.

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

4. The structure of claim 1 wherein the light emitter is an LED configured to emit blue light.

5. The structure of claim 1 wherein during testing the luminescent 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.

6. The structure of claim 1 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.

7. The structure of claim 1 further comprising rollers positioned to guide the luminescent film.

8. The structure of claim 1 wherein the luminescent film comprises phosphor disposed in a flexible material.

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

10. A method comprising:

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

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

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

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

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

11. The method of claim 10 wherein the light from the luminescent film comprises light from the Lambertian light source transmitted through the luminescent film at the same wavelength and light from the Lambertian light source absorbed by the luminescent film and emitted by the luminescent film at a different wavelength.

12. The method of claim 10 wherein altering a property of a portion of the luminescent film comprises changing an amount of luminescent material in the luminescent film.

13. The method of claim 10 wherein the Lambertian light source comprises a mixing chamber having an input port and an output port.

14. The method of claim 13 wherein during testing, the output port of the mixing chamber is spaced less than 500 μm from the luminescent film.

15. The method of claim 13 wherein during testing, the output port of the mixing chamber is spaced less than 1 mm from the input port of the integrating sphere.

16. The method of claim 13 wherein the light emitter is an LED configured to emit blue light.

17. The method of claim 13 wherein during testing the luminescent 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.

18. The method of claim 13 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.

19. The method of claim 10 wherein the luminescent film comprises phosphor disposed in a flexible material.