Wafer-type light emitting device having precisely coated wavelength-converting layer

• US 8,648,370 B2
• Filed: 05/27/2011
• Issued: 02/11/2014
• Est. Priority Date: 06/29/2010
• Status: Active Grant

• Current Assignee: Semileds Optoelectronics Company Limited (SemiLEDs Inc)
• Original Assignee: Semileds Optoelectronics Company Limited (SemiLEDs Inc)
• Inventors: Chu, Chen-Fu, Liu, Wen-Huang, Chang, Yuan-Hsiao, Kao, Hung-Jen, Dan, Chung-Che, Fan, Feng-Hsu
• Primary Examiner(s): Toledo, Fernando L
• Assistant Examiner(s): HALL, VICTORIA KATHLEEN
• Application Number:
  US13/118,334
• Publication Number:
  US 20110316017A1
• Time in Patent Office: 991 Days
• Field of Search: 257 79-103, 438 22- 47
• US Class Current: 257/98
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: H01L 33/505 characterised by the shape, e.g. plate or foil

Abstract

The invention relates to a wafer-type light emitting device having a substrate, one or more light emitting semiconductors formed on the substrate, one or more frames provided over the one or more light emitting semiconductors, and one or more wavelength-converting layers applied on the one or more light emitting semiconductors and confined by the one or more frames, wherein the wafer-type light emitting device is diced into a plurality of separate light emitting units.

Claims

1. A wafer-type light emitting device comprising:

a plurality of light emitting units, wherein the plurality of light emitting units are diced into a plurality of separate and individual light emitting units and each light emitting unit comprises;

a substrate;

a light emitting semiconductor formed adjacent and above said substrate;

a main frame, deposited on said light emitting semiconductor and extending to a side portion of said light emitting semiconductor, for forming a main deposition area;

an inner frame, deposited on said light emitting semiconductor, for forming an inner deposition area, wherein said inner deposition area is within said main deposition area;

a first wavelength-converting layer, deposited within said inner deposition area, and adjacent and above said light emitting semiconductor; and

a second wavelength-converting layer, deposited within said main deposition area, and adjacent and above said first wavelength-converting layer.

2. The wafer-type light emitting device of claim 1, wherein the light emitting units emit a light having a peak wavelength ranging between about 200 nm and about 500 nm.

3. The wafer-type light emitting device of claim 1, wherein said first and second wavelength-converting layers are applied using at least one of precise dispensing, precise stamping, precise jetting, and screen printing.

4. The wafer-type light emitting device of claim 1, wherein said first and second wavelength-converting layers include fluorescent particles mixed with an organic chemical.

5. The wafer-type light emitting device of claim 4, wherein a weight ratio of the fluorescent particles to said organic chemical is about 0.6 to 8.

6. The wafer-type light emitting device of claim 4, wherein said organic chemical is selected from the group consisting of silicone resin, epoxy resin and the combination of silicone resin and epoxy resin.

7. The wafer-type light emitting device of claim 1, wherein said first and second wavelength-converting layers include fluorescent particles mixed with a glass.

8. The wafer-type light emitting device of claim 7, wherein a weight ratio of the fluorescent particles to the glass is about 0.6 to 8.

9. The wafer-type light emitting device of claim 7, wherein said first and second wavelength-converting layers mixed with the glass are applied using at least one of precise dispensing, precise stamping, precise jetting, and screen printing.

10. The wafer-type light emitting device of claim 9, wherein said first and second wavelength-converting layers mixed with the glass are applied at a temperature ranging between about 100°

C. and about 500°

C.

11. The wafer-type light emitting device of claim 1, wherein said first and second wavelength-converting layers have a convex, a concave, a flat, or a pyramid shape.

12. The wafer-type light emitting device of claim 1, wherein said main frame and said inner frame are made of a transparent material.

13. The wafer-type light emitting device of claim 12, wherein the transparent material is epoxy resin, silicone resin, polyimide resin, glass, quartz, acryl resin, polycarbonate resin, SU-8 resist, BCB resist, or parylene resin.

14. The wafer-type light emitting device of claim 1, wherein said main frame and said inner frame are provided using at least one of spin coating, dip coating, chemical vapor deposition, thermal evaporation, and e-beam evaporation.

15. The wafer-type light emitting device of claim 1, wherein said main frame and said inner frame are composed of a single metallic layer or multiple metallic layers.

16. The wafer-type light emitting device of claim 1, wherein said main frame and said inner frame each has a thickness of about 0.1 μ

m to about 200 μ

m.

17. The wafer-type light emitting device of claim 1, wherein said first and second wavelength-converting layers each has a thickness of about 1 μ

m to about 200 μ

m.

18. The wafer-type light emitting device of claim 1, further comprising:

a light diffusion layer provided on said first and second wavelength-converting layers.

19. The wafer-type light emitting device of claim 1, wherein the substrate is opaque.

20. The wafer-type light emitting device of claim 19, wherein the substrate is metal, ceramic, or semiconductor.

21. The wafer-type light emitting device of claim 20, further comprising:

a reflection layer provided between the substrate and said light emitting semiconductor.

22. The wafer-type light emitting device of claim 1, wherein a surface of said light emitting semiconductor that is adjacent to said first and second wavelength-converting layers is roughened.

23. The wafer-type light emitting device of claim 1, wherein said first and second wavelength-converting layers undergo a heat treatment.

24. The wafer-type light emitting device of claim 23, wherein a temperature of said heat treatment is between about 60°

C. and about 300°

C.

25. The wafer-type light emitting device of claim 1, wherein said light emitting semiconductor includes:

a p-type semiconductor layer formed on the substrate;

an activation layer provided on the p-type semiconductor layer; and

an n-type semiconductor layer provided on the activation layer.

26. The wafer-type light emitting device of claim 1, wherein said first and second wavelength-converting layers encapsulate a portion of said main and inner frames.