Wafer-type light emitting device having precisely coated wavelength-converting layer
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.
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 μm to about 200 μm.
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 μm to about 200 μm.
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.