High-efficient light engines using light emitting diodes

• US 7,703,942 B2
• Filed: 12/20/2006
• Issued: 04/27/2010
• Est. Priority Date: 08/31/2006
• Status: Active Grant

• Current Assignee: Rensselaer Polytechnic Institute
• Original Assignee: Rensselaer Polytechnic Institute
• Inventors: Freyssinier, Jean Paul, Gu, Yimin, Narendran, Nadarajah
• Primary Examiner(s): O'Shea; Sandra L
• Assistant Examiner(s): McMillan; Jessica L
• Application Number:
  US11/642,154
• Publication Number:
  US 20080054281A1
• Time in Patent Office: 1,224 Days
• Field of Search: 362/231, 362/800, 362/293, 362/84, 362/246, 362/237, 362/240
• US Class Current: 362/231
• CPC Class Codes: F21K 9/00 Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• 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 33/507 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 33/58 Optical field-shaping elements
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

A light emitting apparatus having a light source for emitting short wavelength radiation and an optic device configured to receive the radiation emitted from the light source. A device directs at least some of the short wavelength radiation emitted from the light source into the optic device and a down conversion material receives at least some of the short wavelength radiation directed into the optic device in one spectral region and emits the radiation in another spectral region.

Claims

1. A light emitting apparatus comprising:

a radiation source for emitting short wavelength radiation;

an optic device configured to receive short wavelength radiation emitted from the radiation source;

a device for directing at least some of the short wavelength radiation emitted from the radiation source into the optic device;

a first portion of the optic device having at least one aperture positioned to allow transfer of at least some of the short wavelength radiation emitted from the radiation source into the optic device; and

a down conversion material receiving at least some of the short wavelength radiation directed into the optic device in one spectral region and emitting at least some of the received radiation in at least one other spectral region.

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

3. The light emitting apparatus of claim 1, wherein the short wavelength radiation source includes at least one of a light emitting diode (LED), a laser diode (LD), or a resonant cavity light emitting diode (RCLED) and the device for directing at least some of the radiation emitted from the source is one of a lens, a GRIN lens, a micro lens, or a ball lens.

4. The light emitting apparatus of claim 1, wherein the down conversion material includes one of a phosphor or other material for converting at least some of the received light into forward transferred light and back transferred radiation.

5. The light emitting apparatus of claim 1, wherein the down conversion material includes non down converting scattering particles.

6. The light emitting apparatus of claim 1, wherein the radiation source is disposed outside the optic device.

7. The light emitting apparatus of claim 1, wherein the device for directing at least some of the short wavelength radiation emitted from the radiation source is disposed outside the optic device.

8. The light emitting apparatus of claim 1, wherein the radiation source and the device for directing at least some of the radiation emitted from the radiation source are disposed outside the optic device.

9. The light emitting apparatus of claim 1, wherein the device for directing at least some of the short wavelength and down converted radiation is disposed between the radiation source and the optic device.

10. The light emitting apparatus of claim 1, further including a reflector disposed around at least a portion of the optic device.

11. The light emitting apparatus of claim 1, wherein a geometric shape of the optic device includes one of a cone, sphere, hyperbola, parabola, ellipse, pyramid or box shape.

12. The light emitting apparatus of claim 1, wherein radiation inside the optic device includes at least one of back transferred radiation from the down conversion material, radiation from the radiation source and radiation emitted, scattered and/or reflected within the optic device and wherein the optic device is adapted to extract radiation from inside the optic device to outside of the optic device.

13. The light emitting apparatus of claim 12, further comprising a collecting device for collecting light extracted to outside of the optic device.

14. The light emitting apparatus of claim 13, wherein the collecting device includes a reflector disposed around at least a portion of the optic device.

15. The light emitting apparatus of claim 1, wherein the radiation source is disposed adjacent a first portion of the optic device.

16. The light emitting apparatus of claim 15, wherein the radiation source is disposed inside at least one reflector.

17. The light emitting apparatus of claim 16, wherein a shape of the at least one reflector is one of concave, parabolic, or flat.

18. The light emitting apparatus of claim 16, wherein the radiation source is a light emitting diode and a shape of the at least one reflector is substantially parabolic.

19. The light emitting apparatus of claim 15, wherein the down conversion material is disposed adjacent a second portion of the optic device.

20. The light emitting apparatus of claim 15, wherein the down conversion material is disposed adjacent a second end of the optic device and further comprising a diffuser layer disposed at least one of adjacent a first side of the down conversion material or adjacent a second side of the down conversion material.

21. The light emitting apparatus of claim 15, wherein the down conversion material is disposed adjacent a second portion of the optic device and further comprising a first diffuser layer disposed adjacent a first side of the down conversion material and a second diffuser layer disposed adjacent a second side of the down conversion material.

22. The light emitting apparatus of claim 15, wherein an inside surface at the first portion of the optic device is a reflective surface.

23. The light emitting apparatus of claim 22, further comprising one of a plurality of bumps or a plurality of conical sections on the reflective surface of the optic device.

24. The light emitting apparatus of claim 1 wherein the radiation source comprises a source for emitting multi-colored light.

25. The light emitting apparatus of claim 1, wherein the radiation source comprises a plurality of light emitting sources, each of the light emitting sources exhibiting a spectrum different than a spectrum of at least some of the other light emitting sources.

26. A light emitting apparatus comprising:

a radiation source for emitting short wavelength radiation, the radiation source including a plurality of semiconductor light emitters, including at least one of a light emitting diode (LED), a laser diode (LD), or a resonant cavity light emitting diode (RCLED);

an optic device configured to receive short wavelength radiation emitted from the plurality of semiconductor light emitters;

a device for directing at least some of the short wavelength radiation emitted from the plurality of semiconductor light emitters into the optic device;

a first portion of the optic device has a plurality of apertures positioned to allow transfer of at least some of the short wavelength radiation from the plurality of semiconductor light emitters into the optic device;

a down conversion material receiving at least some of the short wavelength radiation directed into the optic device in one spectral region and emitting at least some of the received radiation in at least one other spectral region.

27. The light emitting apparatus of claim 26, wherein a plurality of lenses direct the short wavelength radiation from respective semiconductor light emitters through respective apertures.

28. The light emitting apparatus of claim 27, wherein respective semiconductor light emitters are aligned with respective lenses and apertures or transparent areas.

29. The light emitting apparatus of claim 26, wherein respective semiconductor light emitters are disposed one of inside or on respective ones of a plurality of reflectors.

30. The light emitting apparatus of claim 26, wherein the plurality of semiconductor light emitters are disposed outside the optic device.

31. The light emitting apparatus of claim 26, wherein the device for directing at least some of the light emitted from the plurality of semiconductor light emitters is disposed between the plurality of semiconductor light emitters and the optic device.

32. The light emitting apparatus of claim 31 wherein the device for directing at least some of the light from the plurality of semiconductor light emitters is a micro lens layer.

33. A light emitting apparatus comprising:

a radiation source for emitting multi-colored radiation;

an optic device configured to receive at least a portion of the multi-colored radiation emitted by the radiation source;

a device for directing at least some of the multi-colored radiation emitted by the radiation source into the optic device;

a first portion of the optic device having at least one aperture positioned to allow transfer of at least some of the multi-colored radiation emitted from the radiation source into the optic device; and

a diffuser material coupled to the optic device receiving at least some of the multi-colored radiation and converting the received multi-colored radiation into forward transferred radiation and back transferred radiation,

wherein the optic device is configured to extract at least a portion of the back transferred radiation from the optic device.

34. The light emitting apparatus of claim 33, wherein the radiation source comprises a plurality of light emitting sources, each of the light emitting sources exhibiting a spectrum different than a spectrum of at least one of the other light emitting sources.

35. The light emitting apparatus of claim 33 wherein the diffuser material is at least one of a diffuser, a down conversion material, and a microlens.