Color control by alteration of wavelength converting element

• US 7,462,502 B2
• Filed: 05/31/2006
• Issued: 12/09/2008
• Est. Priority Date: 11/12/2004
• Status: Active Grant

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Philips Lumileds Lighting Company LLC (Apollo Global Management, Inc.)
• Inventors: Epler, John E., Steranka, Frank M., Camras, Michael D., Paolini, Steven, Chao Pujol, Oscar Arturo
• Primary Examiner(s): Dang; Phuc T
• Application Number:
  US11/444,592
• Publication Number:
  US 20060258028A1
• Time in Patent Office: 923 Days
• Field of Search: 438/22, 438/25, 438/28, 257/88, 257/89, 257/90, 257/91, 257/98
• US Class Current: 438/22
• CPC Class Codes: H01L 2224/73253 Bump and layer connectors
• CPC Class Codes: H01L 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/508 having a non-uniform spatial arrangement or non-uniform concentration, e.g. patterned wavelength conversion layer, wavelength conversion layer with a concentration gradient of the wavelength conversion material
• CPC Class Codes: H01L 33/58 Optical field-shaping elements

Abstract

A light emitting device is produced by depositing a layer of wavelength converting material over the light emitting device, testing the device to determine the wavelength spectrum produced and correcting the wavelength converting member to produce the desired wavelength spectrum. The wavelength converting member may be corrected by reducing or increasing the amount of wavelength converting material. In one embodiment, the amount of wavelength converting material in the wavelength converting member is reduced, e.g., through laser ablation or etching, to produce the desired wavelength spectrum.

Claims

1. A method comprising:

providing a light emitting element;

depositing a layer of a wavelength converting material over the light emitting element;

determining the wavelength spectrum of light emitted by the combination of the light emitting element and the wavelength converting material; and

altering the amount of wavelength converting material on the light emitting element.

2. The method of claim 1, further comprising:

repeatedly determining the wavelength spectrum of light emitted by the combination of the light emitting element and the wavelength converting material and altering the amount of wavelength converting material until a desired wavelength spectrum of light is produced.

3. The method of claim 2, wherein producing the desired wavelength spectrum of light produces a desired correlated color temperature.

4. The method of claim 2, wherein prodacing the desired wavelength spectrum of light produces a point within a desired area in color space.

5. The method of claim 1, wherein altering the amount of wavelength converting material comprises reducing the amount of wavelength converting material that is deposited on the light emitting element.

6. The method of claim 5, wherein reducing the amount of wavelength converting material that is deposited on the light emitting element comprises one of decreasing the thickness of the wavelength converting material approximately across the entire light emitting element and decreasing the thickness of the wavelength converting material in a localized area of the light emitting element.

7. The method of claim 5, wherein reducing the amount of wavelength converting material that is deposited on the light emitting element is performed by one of etching and ablation.

8. The method of claim 7, wherein altering the amount of wavelength converting material is performed by ablating the layer of wavelength convening material in one or more patterns.

9. The method of claim 8, wherein the pattern is at least one of a series of stripes and a series of holes.

10. The method of claim 8, wherein the pattern is at least one of a design, symbol or emblem.

11. The method of claim 8, wherein ablating the layer of wavelength converting material is performed using multiple passes over the layer of wavelength converting material.

12. The method of claim 1, wherein altering. the amount of wavelength converting material comprises increasing the thickness of the layer of the wavelength converting material.

13. The method of claim 1, wherein determining the wavelength spectrum of light emitted by the combination of the light emitting element and the wavelength converting material further comprises locating the wavelength spectrum of light in a color space and altering the amount of wavelength converting material on the light emitting element based on the location of the wavelength spectrum of light in the color space.

14. The method of claim 1, wherein determining the wavelength spectrum of light emitted by the combination of the light emitting element and the wavelength converting material further comprises generating a spatial map of the wavelength spectrum and altering the amount of wavelength converting material on the light emitting element based on the spatial map.

15. The method of claim 1, wherein depositing a layer of the wavelength converting material over a light emitting element comprises depositing the wavelength converting material on the light emitting element.

16. The method of claim 1, wherein depositing a layer of the wavelength converting material over a light emitting element comprises depositing the wavelength converting material on an optical element that is over the light emitting element.

17. The method of claim 1, wherein the wavelength converting material is a wavelength convening ceramic.

18. The method of claim 1, wherein the light emitting element is a light emitting diode.

19. A method comprising:

providing a light emitting element;

depositing a layer of a wavelength converting material over the light emitting element;

determining the wavelength spectrum of light emitted byte combination of the light emitting element and the wavelength converting material; and

altering the amount of wavelength converting material on the light emitting element in response to the determined wavelength spectrum.

20. The method of claim 19, wherein altering the amount of wavelength convening material comprises reducing the amount of wavelength converting material that was deposited on the light emitting element.

21. The method of claim 20, wherein reducing the amount of wavelength converting material that is deposited on the light emitting element is performed by one of etching and ablation.

22. The method of claim 19, wherein altering the amount of wavelength converting material comprises increasing the thickness of the layer of the wavelength converting material.

23. The method of claim 19, wherein the wavelength convening material is a wavelength converting ceramic.