Wavelength-converting light-emitting devices

• US 7,196,354 B1
• Filed: 09/29/2005
• Issued: 03/27/2007
• Est. Priority Date: 09/29/2005
• Status: Active Grant

• Current Assignee: Luminus Devices Incorporated (Sanan Optoelectronics Company Limited)
• Original Assignee: Luminus Devices Incorporated (Sanan Optoelectronics Company Limited)
• Inventors: Karlicek, Robert F. Jr., Lim, Michael, Erchak, Alexei A., Lidorikis, Elefterios, Venezia, Jo A., Brown, Michael G.
• Primary Examiner(s): Prenty; Mark V.
• Application Number:
  US11/238,667
• Time in Patent Office: 544 Days
• Field of Search: 257/79, 257/98, 257/99, 257/712, 438/29
• US Class Current: 257/79
• 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 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 33/644 in intimate contact or integrated with parts of the device other than the semiconductor body
• CPC Class Codes: H01L 33/648 the elements comprising fluids, e.g. heat-pipes

Abstract

A light-emitting device is provided. The device may include a thermally conductive region in contact with a wavelength-converting region (e.g., a phosphor region). The thermally conductive region may aid in the extraction of heat resulting from light absorption in the wavelength-converting region, which, if excessive, may impair device operation. The presence of a thermally conductive region can enable devices including wavelength-converting regions to operate even at high power levels (e.g., light generated by the light-generating region and/or by the light-emitting device having a total power greater than 0.5 Watts) for long operating lifetimes (e.g., greater than 2,000 hours).

Claims

1. A light-emitting device comprising:

a light-generating region adapted to generate light;

a wavelength-converting region capable of absorbing light generated by the light-generating region and emitting light having a different wavelength than a wavelength of the light generated by the light-generating region; and

a thermally conductive region in contact with the wavelength-converting region and capable of conducting heat generated in the wavelength-converting region, the thermally conductive region comprising a material having a thermal conductivity greater than a thermal conductivity of the wavelength-converting region,

wherein the light-emitting device is adapted to emit light having a total power of greater than 0.5 Watts.

2. The device of claim 1, wherein the thermally conductive region is in contact with a heat sink.

3. The device of claim 2, wherein the heat sink is external of the light-emitting device.

4. The device of claim 1, wherein the thermally conductive region comprises a heat sink.

5. The device of claim 1, further comprising a package including a window, the window comprising the wavelength-converting region.

6. The device of claim 5, wherein the package includes a frame surrounding a portion of the window, the frame comprising the thermally conductive region.

7. The device of claim 5, wherein the window comprises the thermally conductive region.

8. The device of claim 1, wherein the thermally conductive region comprises a layer adjacent to the wavelength-converting region.

9. The device of claim 1, wherein the thermally conductive region comprises a layer adjacent to the wavelength-converting region, the layer being substantially reflective of light emitted from the wavelength-converting region.

10. The device of claim 1, wherein the thermally conductive region comprises a patterned region adjacent to the wavelength-converting region.

11. The device of claim 1, wherein the thermally conductive region is embedded within the wavelength-converting region.

12. The device of claim 11, wherein the thermally conductive region comprises an elongated structure embedded within the wavelength-converting region.

13. The device of claim 1, further comprising a filter constructed and arranged to allow light having at least one selected wavelength to pass therethrough and to reflect light having at least one non-selected wavelength.

14. The device of claim 1, wherein the wavelength-converting region and the light-generating region are portions of a first structure.

15. The device of claim 1, wherein the wavelength-converting region is a portion of a first structure and the light-generating region is a portion of a second structure physically separated from the first structure.

16. The device of claim 15, wherein the wavelength-converting region is formed on a reflective region.

17. The device of claim 1, further comprising a reflective region constructed and arranged to direct light generated by the light-generating region toward the wavelength-converting region.

18. The device of claim 17, wherein the light-generating region is formed over a first portion of a support and the wavelength-converting region is formed over a second portion of the support.

19. The device of claim 18, wherein the thermally conductive region comprises a layer formed on the support and is in contact with the light-generating region and the wavelength-converting region.

20. The device of claim 1, further comprising a light pipe, wherein the light pipe comprises the wavelength-converting region.

21. The device of claim 1, further comprising a light pipe, wherein the wavelength-converting region is formed on the light pipe.

22. The device of claim 1, wherein at least a sidewall of the wavelength-converting region is in contact with the light-generating region.

23. The device of claim 1, wherein the light-generating region surrounds sidewalls of the wavelength-converting region.

24. The device of claim 1, wherein the device further comprises a second light-generating region adapted to emit light.

25. The device of claim 24, wherein the light-generating region is a portion of a first LED and the second light-generating region is a portion of a second LED.

26. The device of claim 25, wherein the device comprises an array of LEDs including at least the first LED and the second LED, wherein the first LED and the second LED are adapted to emit light and the total power of the emitted light from each of the first LED and the second LED is greater than 0.5 Watts.

27. The device of claim 1, wherein the light-generating region is a portion of a first LED and the first LED is adapted to emit light having a total power of greater than 0.5 Watts.

28. The device of claim 1, further comprising a structure defining a cavity, wherein the wavelength-converting region is formed in the cavity and the light-generating region is adapted to emit light into the cavity.

29. The device of claim 28, wherein the light-generating region is formed on a wall of the structure defining the cavity and the wall comprises the thermally conductive region.

30. The device of claim 1, wherein the light-generating region comprises a semiconductor region.

31. The device of claim 30, wherein the semiconductor region comprises a III–

V compound.

32. The device of claim 1, wherein the light-generating region is an LED.

33. The device of claim 1, wherein the wavelength-converting region comprises phosphor material particles dispersed in a second material.

34. The device of claim 1, wherein the wavelength-converting region comprises nanodots.

35. The device of claim 1, wherein the light emitted by the wavelength-converting region has a total power flux of greater than 3 mWatts/mm².

36. The device of claim 1, wherein the light emitted by the wavelength-converting region has a total power density of greater than 1.5 mWatts/mm³, where the total power density is a total power flux per thickness of the wavelength-converting region.

37. The device of claim 1, wherein the light emitted by the light-emitting device has a total power of greater than 1 Watt.

38. The device of claim 1, wherein the light emitted by the light-emitting device has a total power of greater than 5 Watts.

39. The device of claim 1, wherein the light emitted by the light-emitting device has a total power of between 0.5 Watts and 20 Watts.

40. The device of claim 1, wherein the region adapted to emit light comprises an emitting surface having a dielectric function that varies spatially.

41. The device of claim 40, wherein the dielectric function varies spatially according to a pattern.

42. The device of claim 41, wherein the pattern is periodic.

43. The device of claim 42, wherein the pattern is complex periodic.

44. The device of claim 41, wherein the pattern is non-periodic.

45. The device of claim 41, wherein the pattern is a quasi-crystal pattern.

46. A light-emitting device comprising:

a light-generating region adapted to generate light;

a wavelength-converting region capable of absorbing light generated by the light-generating region having a total power of greater than 0.5 Watts and emitting light having a different wavelength than a wavelength of the light generated by the light-generating region; and

a thermally conductive region in contact with the wavelength-converting region and capable of conducting heat generated in the wavelength-converting region, the thermally conductive region comprising a material having a thermal conductivity greater than a thermal conductivity of the wavelength-converting region.

47. The device of claim 46, wherein the thermally conductive region is in contact with a heat sink.

48. The device of claim 46, wherein the semiconductor region is a portion of an LED.

49. The device of claim 48, wherein the light emitted by the LED has a total power flux of greater than 0.03 Watts/mm².

50. The device of claim 46, wherein the semiconductor region comprises an emitting surface having a dielectric function that varies spatially.

51. The device of claim 46, wherein the device further comprises a second light-generating region adapted to emit light.

52. The device of claim 51, wherein the light-generating region is a portion of a first LED and the second light-generating region is a portion of a second LED.

53. The device of claim 52, wherein the device comprises an array of LEDs including at least the first LED and the second LED, wherein the first LED and the second LED are adapted to emit light, each having a total power of greater than 0.5 Watts.

54. The device of claim 46, wherein the wavelength-converting region comprises phosphor material particles dispersed in a second material.

58. The method of claim 51, wherein the total power flux emitted by the LED is greater than 0.03 Watts/mm².

55. A method of operating a light-emitting device comprising:

generating light in a light-generating region of an LED having a total power of greater than 0.5 Watts;

absorbing light generated by the light-generating region in a wavelength-converting region and emitting light having a wavelength different than a wavelength of the light generated in the light-generating region; and

emitting light from the light-emitting device,

wherein the device has an operating lifetime of greater than 2,000 hours.

56. The method of claim 55, further comprising conducting heat generated in the wavelength-converting region in a thermally conductive region comprising a material having a thermal conductivity greater than a thermal conductivity of the wavelength-converting region.

57. The method of claim 55, wherein the device has an operating lifetime of greater than 10,000 hours.

59. A method of forming a light-emitting device, the method comprising:

forming a light-generating region adapted to generate light;

forming a wavelength-converting region capable of absorbing light generated by the light-generating region and emitting light having a different wavelength than a wavelength of the light generated by the light-generating region; and

forming a thermally conductive region in contact with the wavelength-converting region and capable of conducting heat generated in the wavelength-converting region, the thermally conductive region comprising a material having a thermal conductivity greater than a thermal conductivity of the wavelength-converting region,

wherein the light-emitting device is adapted to emit light having a total power of greater than 0.5 Watts.

60. The method of claim 59, further comprising providing a heat sink connectable to the thermally conductive region.