Light emitting devices for light emitting diodes (LEDs)

• US 8,575,639 B2
• Filed: 03/30/2012
• Issued: 11/05/2013
• Est. Priority Date: 02/16/2011
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Hussell, Christopher P.
• Primary Examiner(s): LE, DUNG ANH
• Application Number:
  US13/435,912
• Publication Number:
  US 20120299022A1
• Time in Patent Office: 585 Days
• Field of Search: 257 12- 13, 257 98- 99, 257/103, 257431-433, 257/E21.592, 257/E31.117, 438/22, 438 27- 28, 438 48- 52
• US Class Current: 257/98
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/83192 wherein the layer connectors are disposed only on another item or body to be connected to the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/92247 the second connecting process involving a wire connector
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 25/167 comprising optoelectronic devices, e.g. LED, photodiodes
• 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 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01322 Eutectic Alloys, i.e. obtained by a liquid transforming into two solid phases
• CPC Class Codes: H01L 33/486 adapted for surface mounting
• CPC Class Codes: H01L 33/52 Encapsulations
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls

Abstract

Light emitting devices for light emitting diodes (LEDs) are disclosed. In one embodiment a light emitting device can include a submount and a light emission area disposed over the submount. The light emission area can include one or more light emitting diodes (LEDs), a fillet at least partially disposed about the one or more the LEDs, and filling material. The filling material can be disposed over a portion of the one or more LEDs and a portion of the fillet.

Claims

1. A light emitting device, comprising:

a submount comprising a planar surface;

a light emission area disposed over the submount, wherein the light emission area comprises at least one light emitting diode (LED); and

a fillet at least partially disposed about the light emission area, wherein the fillet and the at least one LED are each disposed along the planar surface of the submount.

2. The light emitting device of claim 1, wherein the fillet is clear or reflective.

3. The light emitting device of claim 2, wherein the fillet comprises silicone.

4. The light emitting device of claim 3, wherein the silicone fillet further comprises reflective particulate material such as titanium dioxide (TiO₂) or aluminum oxide (Al₂O₃).

5. The light emitting device of claim 1, further comprising filling material, wherein the filling material is disposed over a portion of the light emission area and a portion of the fillet.

6. The light emitting device of claim 5, wherein the filling material comprises a silicone encapsulant containing phosphor.

7. The light emitting device of claim 1, wherein the light emission area comprises at least one string of light emitting diodes (LEDs).

8. The light emitting device of claim 1, wherein the light emission area comprises an array of light emitting diodes (LEDs).

9. The light emitting device of claim 8, wherein the light emission area comprises a plurality of LEDs electrically connected in series.

10. The light emitting device of claim 9, comprising a plurality of strings of LEDs electrically connected in series.

11. The light emitting device of claim 10, wherein electrical ends of the plurality of strings of LEDs are electrically connected to areas of electrically conductive traces.

12. The light emitting device of claim 1, wherein the submount comprises a base material and a dielectric laminate disposed over a portion of the base material.

13. The light emitting device of claim 12, wherein the base material comprises aluminum (Al) or an Al-alloy.

14. The light emitting device of claim 13, wherein the Al or Al-alloy has a thickness of approximately 0.5 millimeters (mm) to 1.6 mm.

15. The light emitting device of claim 12, wherein the submount further comprises a copper (Cu) trace disposed over the dielectric laminate.

16. The light emitting device of claim 15, wherein the submount further comprises a layer of solder mask at least partially disposed over the Cu trace.

17. The light emitting device of claim 12, wherein the submount further comprises at least one reflection enhancement layer disposed between portions of the base material and portions of the light emission area.

18. The light emitting device of claim 17, further comprising a retention material at least partially disposed around the light emission area.

19. The light emitting device of claim 18, wherein the retention material is disposed over a portion of the reflection enhancement layer.

20. The light emitting device of claim 17, wherein the reflection enhancement layer comprises one or more transparent or reflective dielectric layers.

21. The light emitting device of claim 1, wherein the fillet comprises a curved upper surface for reducing defects during encapsulation.

22. The light emitting device of claim 1, further comprising a retention material at least partially disposed around the light emission area.

23. The light emitting device of claim 22, wherein the fillet is disposed in an area between the light emission area and a portion of the retention material.

24. The light emitting device of claim 1, wherein the fillet is disposed in an area between the light emission area and a portion of a conductive trace.

25. A light emitting device, comprising:

a submount comprising a planar mounting surface;

one or more light emitting diodes (LEDs) disposed over the submount;

a fillet disposed over a portion of the submount; and

a filling material disposed over a portion of the one or more LEDs and a portion of the fillet

wherein a portion of the fillet is disposed adjacent a portion of the LED along the planar mounting surface of the submount.

26. The light emitting device of claim 25, further comprising a retention material at least partially disposed about the one or more LEDs.

27. The light emitting device of claim 26, wherein the fillet is at least partially disposed between a portion of the retention material and the one or more LEDs.

28. The light emitting device of claim 26, wherein the fillet and retention material are comprised of the same material.

29. The light emitting device of claim 25, wherein the fillet and the filling material are comprised of the same material.

30. The light emitting device of claim 29, wherein the material comprises silicone.

31. The light emitting device of claim 25, wherein the fillet comprises a curved upper surface for reducing defects during encapsulation.

32. The light emitting device of claim 25, wherein the fillet is clear or reflective.

33. The light emitting device of claim 25, wherein the submount comprises a dielectric laminate disposed over a portion of a base material.

34. The light emitting device of claim 33, wherein the base material comprises aluminum (Al) or an Al-alloy.

35. The light emitting device of claim 34, wherein the Al or Al-alloy has a thickness of approximately 0.5 millimeters (mm) to 1.6 mm.

36. The light emitting device of claim 25, wherein the one or more LEDs comprise a plurality of LEDs electrically connected in series.

37. The light emitting device of claim 36, further comprising a plurality of strings of LEDs electrically connected in series.

38. The light emitting device of claim 37, wherein electrical ends of the plurality of strings of LEDs are electrically connected to areas of electrically conductive traces.

39. A light emitting device, comprising:

a submount;

a light emission area disposed over the submount; and

a retention material at least partially disposed around the light emission area;

wherein the retention material comprises an outer edge portion comprising an integrally formed fillet at least partially disposed in the light emission area.

40. The light emitting device of claim 39, wherein the outer edge portion comprises a concave upper surface.

41. The light emitting device of claim 39, wherein the submount comprises a base material and at least one reflection enhancement layer, wherein the reflection enhancement layer is at least partially disposed between portions of the light emission area and portions of the base material.

42. The light emitting device of claim 41, wherein the outer edge portion is disposed over a portion of the reflection enhancement layer.

43. A light emitting device, comprising:

a submount;

a light emission area comprising at least one light emitting diode (LED) disposed over the submount; and

a fillet at least partially disposed about the light emission area;

wherein the fillet is directly adjacent to a portion of the submount; and

wherein a portion of the fillet and a portion of the at least one LED are coplanar along a portion of the submount.

44. The light emitting device of claim 43, further comprising a retention material disposed about the light emission area.

45. The light emitting device of claim 43, wherein the fillet is an integral portion of the retention material.

46. The light emitting device of claim 43, wherein the submount comprises a base material and at least one reflection enhancement layer disposed over the base material, at least partially between the base material and the light emission area.

47. The light emitting device of claim 46, wherein the fillet is adjacent to a portion of the reflection enhancement layer.

48. The light emitting device of claim 46, wherein the submount further comprises a dielectric laminate at least partially disposed over the base material in an area outside of the light emission area.

49. The light emitting device of claim 48, wherein the fillet is directly adjacent to a portion of the reflection enhancement layer and a portion of the dielectric laminate.

50. The light emitting device of claim 43, wherein the light emission area comprises a plurality of LEDs and a filling material.

51. The light emitting device of claim 50, wherein the filling material comprises an encapsulant having a selective amount of phosphor disposed therein.

52. The light emitting device of claim 51, wherein the fillet comprises a concave upper surface.