Granted Patent B2

US 7,888,691 · App. 12/201,428 · Granted Feb 15, 2011

Abstract

Claims (36)

1. A structure comprising:

a semiconductor light emitting device 34 comprising a light emitting layer disposed between an n-type region and a p-type region, wherein the light emitting layer is adapted to emit first light having a first peak wavelength;

a first wavelength converting material 38 adapted to absorb the first light and emit second light having a second peak wavelength;

a second wavelength converting material 36 adapted to absorb one of the first light and the second light and emit third light having a third peak wavelength;

wherein the first and second wavelength converting materials are disposed in a path of light emitted by the semiconductor light emitting device; and

a filter 40 adapted to reflect fourth light having a fourth peak wavelength and transmit light having a peak wavelength longer or shorter than the fourth peak wavelength, wherein the fourth light comprises one of a portion of the second light and a portion of the third light, and wherein the filter is disposed in the path of at least a portion of the first, second, and third light.

2. The structure of claim 1 wherein:

the first wavelength converting material 38 is disposed in a ceramic layer; and

the second wavelength converting material 36 is a powder disposed in a transparent material layer.

3. The structure of claim 1 wherein the first wavelength converting material 38 and the second wavelength converting material 36 are powders that are mixed and disposed in a transparent material disposed over the semiconductor light emitting device 34 .

4. The structure of claim 1 wherein:

at least one of the first wavelength converting material 38 and the second wavelength converting material 36 is disposed on the semiconductor light emitting device 34 , and

the filter 40 is in direct contact with one of the first and second wavelength converting materials.

5. The structure of claim 1 wherein the filter 40 is a distributed Bragg reflector.

6. The structure of claim 1 wherein a surface of the filter 40 is within 500 μm of a surface of the semiconductor light emitting device 34 .

7. The structure of claim 1 wherein the filter 40 comprises a stack of dielectric layers.

8. The structure of claim 1 wherein the filter 40 is a first filter, the structure further comprising a second filter layer 26 comprising:

a plurality of first pixel locations, wherein at each first pixel location the second filter is adapted to transmit red light and absorb green and blue light;

a plurality of second pixel locations, wherein at each second pixel location the second filter is adapted to transmit green light and absorb red and blue light; and

a plurality of third pixel locations, wherein at each third pixel location the second filter is adapted to transmit blue light and absorb red and green light.

9. The structure of claim 1 wherein at least one of the first wavelength converting material 38 and the second wavelength converting material 36 is spaced apart from the semiconductor light emitting device 34 .

10. The structure of claim 1 wherein the fourth peak wavelength is between the first peak wavelength and the second peak wavelength.

11. The structure of claim 1 wherein the fourth peak wavelength is between the second peak wavelength and the third peak wavelength.

12. A structure comprising:

at least one light source 20 comprising a semiconductor light emitting device;

a first filter layer 26 disposed over the at least one light source, wherein the first filter layer comprises:

a plurality of first pixel locations, wherein at each first pixel location the first filter is adapted to transmit light at a first peak wavelength and absorb light at second and third peak wavelengths;

a plurality of second pixel locations, wherein at each second pixel location the first filter is adapted to transmit light at the second peak wavelength and absorb light at the first and third peak wavelengths; and

a plurality of third pixel locations, wherein at each third pixel location the first filter is adapted to transmit light at the third peak wavelength and absorb light at the first and second peak wavelengths;

a liquid crystal layer 28 disposed over the first filter layer; and

a second filter layer 40 disposed between the at least one light source and the first filter layer, wherein the second filter layer is adapted to transmit light at the first, second, and third peak wavelengths and reflect light at a fourth peak wavelength.

13. The structure of claim 12 wherein the first filter layer 26 is adapted to absorb light of the fourth peak wavelength.

14. The structure of claim 12 wherein:

the semiconductor light emitting device is configured to emit light having a blue peak wavelength;

the light source further comprises a first wavelength converting material 38 adapted to emit light having a green or yellow peak wavelength and a second wavelength converting material 36 adapted to emit light having a red peak wavelength; and

the second filter layer 40 is disposed in direct contact with one of the first and second wavelength converting materials.

Assignments (6)