Photon extraction from ultraviolet light-emitting devices

Patent metadata

Field	Value
Publication number	US-9935247-B2
Application number	US-201514806761-A
Country	US
Kind code	B2
Filing date	Jul 23, 2015
Priority date	Jul 23, 2014
Publication date	Apr 3, 2018
Grant date	Apr 3, 2018

Abstract

In various embodiments, a layer of organic encapsulant is provided over a surface of an ultraviolet (UV) light-emitting semiconductor die, and at least a portion of the encapsulant is exposed to UV light to convert at least some of said portion of the encapsulant into non-stoichiometric silica material. The non-stoichiometric silica material includes silicon, oxygen, and carbon, and a carbon content of the non-stoichiometric silica material is greater than 1 ppm and less than 40 atomic percent.

First claim

What is claimed is:

1. A method of assembling and burning in an illumination device, the method comprising:
providing a layer of an organic encapsulant over a surface of an ultraviolet (UV) light-emitting semiconductor die; and
exposing at least a portion of the encapsulant to UV light to convert at least some of said portion of the encapsulant into non-stoichiometric silica material, at least a portion of the UV light being emitted by the semiconductor die,
wherein the non-stoichiometric silica material comprises silicon, oxygen, and carbon, a carbon content of the non-stoichiometric silica material being greater than 1 ppm and less than 40 atomic percent, and
wherein, during exposure of the at least a portion of the encapsulant to UV light, a silicon content and an oxygen content of the at least a portion of the encapsulant approach those of silica.

2. The method of claim 1 , wherein the carbon content of the non-stoichiometric silica material is greater than 1 atomic percent.

3. The method of claim 1 , wherein the carbon content of the non-stoichiometric silica material is less than 30 atomic percent.

4. The method of claim 1 , wherein the carbon content of the non-stoichiometric silica material is less than 20 atomic percent.

5. A method assembling and burning in an illumination device, the method comprising:
providing a layer of an organic encapsulant over a surface of an ultraviolet (UV) light-emitting semiconductor die;
disposing a rigid lens on the encapsulant opposite the semiconductor die; and
exposing at least a portion of the encapsulant to UV light to convert at least some of said portion of the encapsulant into non-stoichiometric silica material,
wherein the non-stoichiometric silica material comprises silicon, oxygen, and carbon, a carbon content of the non-stoichiometric silica material being greater than 1 ppm and less than 40 atomic percent.

6. The method of claim 5 , wherein the rigid lens is inorganic.

7. The method of claim 5 , wherein the rigid lens comprises at least one of fused silica, quartz, or sapphire.

8. The method of claim 5 , further comprising disposing an attachment material around at least a portion of the semiconductor die and around at least a portion of the rigid lens.

9. The method of claim 8 , wherein the attachment material comprises a resin.

10. The method of claim 8 , wherein the attachment material is opaque to UV light.

11. The method of claim 8 , wherein a top surface of the attachment material is disposed above a bottom surface of the rigid lens by no more than 0.5 mm.

12. The method of claim 8 , wherein a top surface of the attachment material is disposed above a bottom surface of the rigid lens by no more than 0.3 mm.

13. The method of claim 5 , wherein the rigid lens is attached to the semiconductor die via application of a force sufficient to minimize a thickness of the encapsulant between the rigid lens and the semiconductor die.

14. The method of claim 5 , wherein, after attachment of the rigid lens, the thickness of the encapsulant is insufficient to prevent propagation of thermal expansion mismatch-induced strain between the rigid lens and the semiconductor die.

15. The method of claim 5 , wherein, after attachment of the rigid lens, the thickness of the encapsulant is approximately 10 μm or less.

16. The method of claim 5 , wherein the rigid lens is at least partially hemispherical.

17. The method of claim 16 , wherein the rigid lens is substantially hemispherical.

18. The method of claim 16 , wherein the rigid lens has a substantially hemispherical portion and a substantially cylindrical portion disposed thereunder.

19. The method of claim 5 , wherein the rigid lens is a flat plate.

20. The method of claim 5 , wherein at least a portion of a top surface of the rigid lens is at least one of patterned or textured to enhance light emission therefrom.

21. The method of claim 1 , wherein the encapsulant comprises silicone before the exposure to UV light.

22. The method of claim 1 , wherein the encapsulant comprises silicone oil or silicone resin before the exposure to UV light.

23. The method of claim 1 , wherein (i) before exposure to UV light the encapsulant has a carbon content greater than 40 atomic percent, and (ii) after exposure to UV light the non-stoichiometric silica material has a carbon content less than 30 atomic percent.

24. The method of claim 1 , further comprising disposing a barrier between the semiconductor die and at least a portion of the encapsulant, the barrier comprising a material opaque to UV light.

25. The method of claim 24 , wherein the barrier comprises a resin opaque to UV light.

26. The method of claim 24 , wherein the barrier comprises a material reflective to UV light.

27. The method of claim 24 , wherein the barrier comprises at least one of aluminum or polytetrafluoroethylene.

28. The method of claim 1 , wherein the semiconductor die is a light-emitting diode die.

29. The method of claim 1 , wherein the semiconductor die is a laser die.

30. The method of claim 1 , wherein the at least a portion of the encapsulant is exposed to UV light for a period of approximately 100 hours to approximately 300 hours.

31. The method of claim 1 , wherein a portion of the UV light to which the at least a portion of the encapsulant is exposed is emitted by a device other than the semiconductor die.

32. The method of claim 1 , wherein the at least a portion of the encapsulant is exposed to UV light having a wavelength selected from the range of approximately 210 nm to approximately 280 nm.

33. A method of assembling and burning in an illumination device, the method comprising:
providing a layer of an organic encapsulant over a surface of an ultraviolet (UV) light-emitting semiconductor die; and
exposing at least a portion of the encapsulant to UV light to convert at least some of said portion of the encapsulant into non-stoichiometric silica material, at least a portion of the UV light being emitted by the semiconductor die,
wherein the non-stoichiometric silica material comprises silicon, oxygen, and carbon, a carbon content of the non-stoichiometric silica material being greater than 1 ppm and less than 40 atomic percent, and
wherein exposing the at least a portion of the encapsulant to UV light comprises at least partially oxidizing the at least a portion of the encapsulant.

34. The method of claim 1 , wherein exposing the at least a portion of the encapsulant to UV light comprises altering a refractive index of the at least a portion of the encapsulant.

35. The method of claim 1 , wherein exposing the at least a portion of the encapsulant to UV light comprises forming one or more scattering areas within the at least a portion of the encapsulant.

36. The method of claim 1 , further comprising, after exposing at least a portion of the encapsulant to UV light to convert at least some of said portion of the encapsulant into non-stoichiometric silica material, placing the semiconductor die on or within a system configured to utilize UV light emitted by the semiconductor die.

37. The method of claim 36 , wherein the system is configured to utilize UV light emitted by the semiconductor die for at least on

Assignees

• Kitamura Ken
• Toita Masato
• Ishii Hironori
• Wang Yuting
• Schowalter Leo J
• Chen Jianfeng
• Grandusky James R
• Crystal Is Inc

Inventors

• Kitamura Ken
• Toita Masato
• Ishii Hironori
• Wang Yuting
• Schowalter Leo J
• Chen Jianfeng
• Grandusky James R

Classifications

• H01L2933/0058

  Electricity · mapped topic

• H01L33/58

  Electricity · mapped topic

• H01L2933/005

  Electricity · mapped topic

• H01L33/54

  Electricity · mapped topic

• H01L33/56 Primary

  Electricity · mapped topic