LED package with front surface heat extractor

• US 20060091414A1
• Filed: 10/29/2004
• Published: 05/04/2006
• Est. Priority Date: 10/29/2004
• Status: Abandoned Application

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Wheatley, John A., Ouderkirk, Andrew J., Leatherdale, Catherine A.
• Application Number:
  US10/977,241
• Publication Number:
  US 20060091414A1
• Time in Patent Office: Days
• US Class Current: 257/99
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H01L 33/64 Heat extraction or cooling elements

Abstract

Light sources are disclosed utilizing LED dies having at least one emitting surface. An optical element is disclosed for efficiently extracting light out of an LED die by controlling the angular distribution of the emitted light. The optical element has an input surface that is optically coupled to the emitting surface, an output surface that is larger in surface area than the input surface, and at least one intermediate surface. A heat sink thermally coupled to the intermediate surface of the optical element extracts heat from the emitting surface of the LED die via the optical element.

Claims

1. A light source, comprising:

an LED die having at least one emitting surface;

an optical element including an input surface optically coupled to the at least one emitting surface, an output surface larger than the input surface, and at least one intermediate surface; and

a heat sink thermally coupled to the at least one intermediate surface.

2. The light source of claim 1, wherein the optical element is an optical collimator.

3. The light source of claim 1, wherein the optical element is shaped as a taper.

4. The light source of claim 1, wherein the optical element is shaped as a batwing.

5. The light source of claim 1, wherein the input surface of the optical element contacts the at least one emitting surface of the LED die.

6. The light source of claim 1, wherein the input surface of the optical element is bonded to the at least one emitting surface of the LED die.

7. The light source of claim 1, wherein a refractive index of the optical element is within 25% of a refractive index of the emitting surface.

8. The light source of claim 1, wherein a refractive index of the optical element is at least 1.8.

9. The light source of claim 1, wherein a refractive index of the optical element is at least 2.0.

10. The light source of claim 1, wherein the at least one intermediate surface is highly reflective.

11. The light source of claim 10, wherein the optical element comprises a reflective metallic coating over the at least one intermediate surface.

12. The light source of claim 10, wherein the optical element comprises a low index coating over the at least one intermediate surface.

13. The light source of claim 1, further comprising a thin optically conducting layer disposed between the input surface and the emitting surface.

14. The light source of claim 13, wherein the thin optically conducting layer comprises a liquid.

15. The light source of claim 13, wherein the thin optically conducting layer is also thermally conducting.

16. The light source of claim 1, wherein the optical element comprises a material having a thermal diffusivity of at least about 0.01 cm²/s.

17. The light source of claim 1, further comprising a second heat sink thermally coupled to a base of the LED die.

18. A light source, comprising:

an LED die having a primary emitting surface;

a transparent optical element including an input surface optically coupled to the primary emitting surface, an output surface larger than said input surface, and at least one intermediate surface; and

means for extracting heat out of the at least one intermediate surface.

19. The light source of claim 18, wherein the optical element is an optical collimator.

20. The light source of claim 18, wherein the optical element is shaped as a taper.

21. The light source of claim 18, wherein the optical element is shaped as a batwing.

22. The light source of claim 18, wherein the input surface of the optical element contacts the primary emitting surface of the light source.

23. The light source of claim 18, wherein the input surface of the optical element is bonded to the primary emitting surface of the light source.

24. The light source of claim 18, wherein a refractive index of the optical element is within 25% of a refractive index of the primary emitting surface.

25. The light source of claim 18, wherein a refractive index of the optical element is at least 1.8.

26. The light source of claim 18, wherein a refractive index of the optical element is at least 2.0.

27. The light source of claim 18, wherein the at least one intermediate surface is highly reflective.

28. The light source of claim 27, wherein the optical element comprises a reflective metallic coating over the at least one intermediate surface.

29. The light source of claim 27, wherein the optical element comprises a low index coating over the at least one intermediate surface.

30. The light source of claim 18, further comprising a thin optically conducting layer disposed between the input surface and the primary emitting surface.

31. The light source of claim 30, wherein the thin optically conducting layer comprises a liquid.

32. The light source of claim 30, wherein the thin optically conducting layer is also thermally conducting.

33. The light source of claim 18, wherein the optical element comprises a material having a thermal diffusivity of at least about 0.01 cm²/s.

34. The light source of claim 18, further comprising a heat sink thermally coupled to a base of the LED die.

35. A light source, comprising:

an LED die having a primary emitting surface,

a transparent optical element including an input surface optically coupled to the proximate the primary emitting surface, an output surface larger than said input surface, and at least one side surface disposed between the input surface and the output surface; and

means for extracting heat out of the at least one side surface.

36. The light source of claim 35, wherein the optical element is an optical collimator.

37. The light source of claim 35, wherein the optical element is shaped as a taper.

38. The light source of claim 35, wherein the input surface of the optical element contacts the primary emitting surface of the LED die.

39. The light source of claim 35, wherein the input surface of the optical element is bonded to the primary emitting surface of the LED die.

40. The light source of claim 35, wherein a refractive index of the optical element is within 25% of a refractive index of the primary emitting surface.

41. The light source of claim 35, wherein a refractive index of the optical element is at least 1.8.

42. The light source of claim 35, wherein a refractive index of the optical element is at least 2.0.

43. The light source of claim 35, wherein the at least one side surface is highly reflective.

44. The light source of claim 43, wherein the optical element comprises a reflective metallic coating over the at least one side surface.

45. The light source of claim 43, wherein the optical element comprises a low index coating over the at least one side surface.

46. The light source of claim 35, further comprising a thin optically conducting layer disposed between the input surface and the primary emitting surface.

47. The light source of claim 46, wherein the thin optically conducting layer comprises a liquid.

48. The light source of claim 46, wherein the thin optically conducting layer is also thermally conducting.

49. The light source of claim 35, wherein the optical element comprises a material having a thermal diffusivity of at least about 0.01 cm²/s.

50. The light source of claim 35, further comprising a heat sink thermally coupled to a base of the LED die.