High-power white LEDs and manufacturing method thereof

• US 8,164,825 B2
• Filed: 01/10/2011
• Issued: 04/24/2012
• Est. Priority Date: 11/17/2006
• Status: Active Grant

• Current Assignee: Rensselaer Polytechnic Institute
• Original Assignee: Rensselaer Polytechnic Institute
• Inventors: Narendran, Nadarajah, Gu, Yimin
• Primary Examiner(s): Petkovsek, Daniel
• Application Number:
  US12/987,315
• Publication Number:
  US 20110102884A1
• Time in Patent Office: 470 Days
• Field of Search: 359326-332, 362/26, 362/27, 362/222, 362/225, 362/228, 362/235, 362/293, 362/329, 362/330, 362/555, 362/558, 362/560, 362/582
• US Class Current: 359/326
• CPC Class Codes: H01L 2933/0091 Scattering means in or on the semiconductor body or semiconductor body package H01L33/22 takes precedence
• CPC Class Codes: H01L 33/08 with a plurality of light emitting regions, e.g. laterally discontinuous light emitting layer or photoluminescent region integrated within the semiconductor body H01L27/15 takes precedence
• CPC Class Codes: H01L 33/483 Containers
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• 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
• CPC Class Codes: H01L 33/507 the elements being in intimate contact with parts other than the semiconductor body or integrated with parts other than the semiconductor body
• CPC Class Codes: H01L 33/56 Materials, e.g. epoxy or silicone resin
• CPC Class Codes: H01L 33/58 Optical field-shaping elements

Abstract

A light emitting apparatus has a radiation source for emitting short wavelength radiation. A down conversion material receives and down converts at least some of the short wavelength radiation emitted by the radiation source and back transfers a portion of the received and down converted radiation. An optic device adjacent the down conversion material at least partially surrounds the radiation source. The optic device is configured to extract at least some of the back transferred radiation. A sealant substantially seals a space between the radiation source and the optic device.

Claims

1. A light emitting apparatus comprising:

a radiation source for emitting short wavelength radiation;

an optic device having a top surface distal the radiation source, a bottom surface proximal the radiation source, the proximal end of the optic device having a width smaller that a width of the distal end, and at least one substantially transparent sidewall extending between the top surface and the bottom surface;

a down conversion material, disposed on the top surface of the optic device and extending from the at least one transparent sidewall, receiving and down converting at least some of the short wavelength radiation emitted by the radiation source and back transferring a portion of the received and down converted radiation;

the optic device adjacent the down conversion material and at least partially surrounding the radiation source, the optic device configured to i) receive at least a portion of the radiation back transferred from the down conversion material and ii) transfer at least some of the received portion of back-transferred radiation outside the optic device through the at least one substantially transparent sidewall; and

at least one sealant for substantially sealing a space between the radiation source and the optic device.

2. The light emitting apparatus of claim 1, wherein the optic device has an aperture, at least a portion of the radiation source being disposed inside the aperture.

3. The light emitting apparatus of claim 2, further comprising a plurality of radiation sources for emitting short wavelength radiation disposed inside the aperture, wherein the at least one sealant substantially seals respective spaces between each respective radiation source and the optic device.

4. The light emitting apparatus of claim 1 wherein the at least one sealant material is one of a silicone, a polymer, an epoxy, or another radiation transmissive material.

5. The light emitting apparatus of claim 1, wherein the optic device comprises one of glass, acrylic, or other substantially radiation transmissive material.

6. The light emitting apparatus of claim 1, further comprising a lens adjacent the down conversion material for receiving radiation forward transferred from the down conversion material.

7. The light emitting apparatus of claim 1, wherein the radiation source comprises at least one of a light emitting diode (LED), a laser diode (LD), or a resonant cavity light emitting diode (RCLED).

8. The light emitting apparatus of claim 1, wherein the radiation source is domeless.

9. The light emitting apparatus of claim 1, wherein the radiation source is immediately adjacent the optic device.

10. The light emitting apparatus of claim 1, wherein the down conversion material includes at least one of a phosphor or quantum dots for absorbing radiation in one spectral region and emitting radiation in another spectral region.

11. The light emitting apparatus of claim 1, further comprising a reflector at least partially surrounding the optic device for directing at least some of the radiation extracted from the optic device in a predetermined direction.

12. The light emitting device of claim 11, wherein a shape of the reflector is one of a parabola or an ellipse.

13. The light emitting apparatus of claim 11, wherein the reflector transfers heat away from the radiation source.

14. The light emitting apparatus of claim 11, further comprising a lens adjacent the down conversion material for receiving radiation forward transferred from the down conversion material and the radiation directed by the reflector.

15. The light emitting apparatus of claim 14, wherein the lens is coupled to the down conversion material.

16. The light emitting apparatus of claim 14, wherein the lens is coupled to the reflector.

17. The light emitting apparatus of claim 1, further comprising at least one reflective surface disposed on the optic device adjacent the radiation source.

18. The light emitting apparatus of claim 17, wherein the at least one reflective surface is disposed at least one of along an outside of a wall of the optic device, along an inside of a wall of the optic device, or embedded in a wall of the optic device.

19. The light emitting apparatus of claim 18, wherein a length of the at least one reflective surface is less than a length of the wall of the optic device.

20. The light emitting apparatus of claim 19, wherein the radiation source is disposed on a heat sink.

21. The light emitting apparatus of claim 20, wherein the optic device has an aperture, and

the radiation source and

at least a portion of the heat sink are disposed within the aperture.

22. The light emitting apparatus of claim 21, further comprising

a. a second reflective surface on the heat sink at least partially surrounding the optic device for directing at least some of the radiation extracted from the optic device in a predetermined direction;

and

b. a third reflective surface on the heat sink disposed in an aperture of the optic device.

23. A light emitting apparatus comprising:

a respective plurality of radiation sources for emitting short wavelength radiation;

a plurality of optic devices each having a top surface distal the radiation source, a bottom surface proximal the radiation source, the proximal end of at least one of the plurality of optic devices having a width smaller that a width of the distal end, and at least one substantially transparent sidewall extending between the top surface and the bottom surface;

a plurality of down conversion material layers respectively receiving and down converting at least some of the short wavelength radiation emitted by respective ones of the radiation sources and back transferring respective portions of the respectively received and down converted radiation;

respective ones of the optic devices being adjacent respective down conversion material layers, the respective ones of the optic devices at least partially surrounding respective ones of the radiation sources, the respective optic devices each configured to i) receive at least a portion of the radiation back transferred from the respective down conversion material layers or radiation from the respective radiation sources and ii) transfer at least some of the received portion of back-transferred radiation outside respective ones of the optic devices through their respective at least one substantially transparent sidewall; and

at least one sealant for substantially sealing respective spaces between respective radiation sources and respective optic devices.

24. A light emitting apparatus comprising:

a plurality of radiation sources for emitting short wavelength radiation;

an optic device having a top surface distal the radiation source, a bottom surface proximal the radiation source, the proximal end of the optic device having a width smaller that a width of the distal end, and at least one substantially transparent sidewall extending between the top surface and the bottom surface;

a down conversion material, disposed on the top surface of the optic device and extending from the at least one transparent sidewall, receiving and down converting at least some of the short wavelength radiation from at least one of the plurality of radiation sources and back transferring a portion of the received and down converted radiation;

the optic device adjacent the down conversion material and at least partially surrounding the plurality of radiation sources, the optic device configured to i) receive at least a portion of the radiation back transferred from the down conversion material and ii) transfer at least some of the received portion of back-transferred radiation outside the optic device through the at least one substantially transparent sidewall; and

at least one sealant for substantially sealing at least one space between respective ones of the plurality of radiation sources and the optic device.

25. The light emitting apparatus of claim 24, wherein the at least one sealant substantially seals respective spaces between the plurality of radiation sources and the optic device.

26. The light emitting apparatus of claim 24, wherein the optic device has an aperture, at least a portion of each of the plurality of radiation sources being disposed within the aperture.