Light-emitting devices having multiple encapsulation layers with at least one of the encapsulation layers including nanoparticles and methods of forming the same

• US 20050224829A1
• Filed: 04/06/2004
• Published: 10/13/2005
• Est. Priority Date: 04/06/2004
• Status: Active Grant

• Current Assignee: CREE Led Incorporated (Smart Global Holdings Incorporated)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Negley, Gerald H., Tarsa, Eric
• Granted Patent: US 7,868,343 B2
• Time in Patent Office: Days
• US Class Current: 257/99
• CPC Class Codes: H01L 33/52 Encapsulations
• CPC Class Codes: H01L 33/56 Materials, e.g. epoxy or silicone resin
• CPC Class Codes: H05B 33/04 Sealing arrangements , e.g. against humidity

Abstract

A light-emitting device includes an active region that is configured to emit light responsive to a voltage applied thereto. A first encapsulation layer at least partially encapsulates the active region and includes a matrix material and nanoparticles, which modify at least one physical property of the first encapsulation layer. A second encapsulation layer at least partially encapsulates the first encapsulation layer.

Claims

1. A light-emitting device, comprising:

an active region that is configured to emit light responsive to a voltage applied thereto;

a first encapsulation layer that at least partially encapsulates the active region, the first encapsulation layer comprising a matrix material and nanoparticles that modify at least one physical property of the first encapsulation layer; and

a second encapsulation layer that at least partially encapsulates the first encapsulation layer.

2. The light-emitting device of claim 1, wherein the matrix material comprises silicone, a silicone compound, an optical gel, epoxy resin, glass, sol-gel, aerogel, and/or an optically stable polymer.

3. The light-emitting device of claim 1, wherein the first encapsulation layer is substantially transparent.

4. The light-emitting device of claim 1, wherein the nanoparticles comprise TiO₂, diamond, silicon carbide, scattering particles, fillers, phosphors, and/or light conversion materials.

5. The light-emitting device of claim 1, wherein the at least one physical property comprises index of refraction, thermal conductivity, mechanical strength, abrasion resistance, and/or optical stability.

6. The light-emitting device of claim 1, wherein the matrix material is a first matrix material, and the nanoparticles are first nanoparticles and wherein the second encapsulation layer comprises a second matrix material and second nanoparticles that modify at least one physical property of the second encapsulation layer.

7. The light-emitting device of claim 6, wherein the second matrix material comprises silicone, a silicone compound, an optical gel, epoxy resin, glass, sol-gel, aerogel, and/or an optically stable polymer.

8. The light-emitting device of claim 6, wherein the second encapsulation layer is substantially transparent.

9. The light-emitting device of claim 6, wherein the second nanoparticles comprise TiO₂, diamond, silicon carbide, scattering particles, fillers, phosphors, and/or light conversion materials.

10. The light-emitting device of claim 6, wherein the at least one physical property of the second encapsulation layer comprises index of refraction, thermal conductivity, mechanical strength, abrasion resistance, and/or optical stability.

11. The light-emitting device of claim 1, wherein an outer surface of the first encapsulation layer, opposite the active region, is shaped so that light rays from the active region are not incident on the first encapsulation layer at an angle that is greater than a critical angle.

12. A method of forming a light-emitting device, comprising:

forming an active region that is configured to emit light responsive to a voltage applied thereto;

forming a first encapsulation layer that at least partially encapsulates the active region, the first encapsulation layer comprising a matrix material and nanoparticles that modify at least one physical property of the first encapsulation layer; and

forming a second encapsulation layer that at least partially encapsulates the first encapsulation layer.

13. The method of claim 12, wherein the matrix material comprises silicone, a silicone compound, an optical gel, epoxy resin, glass, sol-gel, aerogel, and/or an optically stable polymer.

14. The method of claim 12, wherein the first encapsulation layer is substantially transparent.

15. The method of claim 12, wherein the nanoparticles comprise TiO₂, diamond, silicon carbide, scattering particles, fillers, phosphors, and/or light conversion materials.

16. The method of claim 12, wherein the at least one physical property comprises index of refraction, thermal conductivity, mechanical strength, abrasion resistance, and/or optical stability.

17. The method of claim 12, wherein the matrix material is a first matrix material, and the nanoparticles are first nanoparticles and wherein the second encapsulation layer comprises a second matrix material and second nanoparticles that modify at least one physical property of the second encapsulation layer.

18. The method of claim 17, wherein the second matrix material comprises silicone, a silicone compound, an optical gel, epoxy resin, glass, sol-gel, aerogel, and/or an optically stable polymer.

19. The method of claim 17, wherein the second encapsulation layer is substantially transparent.

20. The method of claim 17, wherein the second nanoparticles comprise TiO₂, diamond, silicon carbide, scattering particles, fillers, phosphors, and/or light conversion materials.

21. The method of claim 17, wherein the at least one physical property of the second encapsulation layer comprises index of refraction, thermal conductivity, mechanical strength, abrasion resistance, and/or optical stability.

22. The method of claim 12, wherein an outer surface of the first encapsulation layer, opposite the active region, is shaped so that light rays from the active region are not incident on the first encapsulation layer at an angle that is greater than a critical angle.