High efficiency LEDs

• US 8,455,882 B2
• Filed: 09/30/2011
• Issued: 06/04/2013
• Est. Priority Date: 10/15/2010
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Yao, Zhimin Jamie
• Primary Examiner(s): Lebentritt, Michael
• Application Number:
  US13/250,289
• Publication Number:
  US 20120256200A1
• Time in Patent Office: 613 Days
• Field of Search: 257 76- 99, 257/E33.023, 257 57- 73
• US Class Current: 257/76
• CPC Class Codes: H01L 2224/32014 the layer connector being smaller than the bonding area, e.g. bond pad
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/32257 the layer connector connecting to a bonding area disposed in a recess of the surface of the item
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/4918 being disposed on at least two different sides of the body, e.g. dual array
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 27/156 two-dimensional arrays
• 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 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/01087 Francium [Fr]
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/22 Roughened surfaces, e.g. at the interface between epitaxial layers
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/405 Reflective materials
• 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

A light emitting device and method of fabricating the same is disclosed that comprises at least one light emitter comprising an active region which emits light. The device further comprising a submount arranged such that the at least one light emitter is mounted to the submount such that the active region is angled in relation to the submount.

Claims

1. A light emitting device, comprising:

at least one light emitter comprising an active region which emits light; and

a submount arranged such that said at least one light emitter is mounted to said submount such that said active region is angled in relation to said submount, wherein a mounting surface of said light emitter is angled in relation to a plane of said active region.

2. The light emitting device of claim 1, wherein said light emitter is comprised of a LED.

3. The light emitting device of claim 2 further wherein said LED comprises an at least an n-type semiconductor layer, a p-type semiconductor layer, and a substrate, such that said active region is formed at the interface of said n-type semiconductor layer and said p-type semiconductor layer.

4. The light emitting device of claim 1 wherein the primary emission surfaces of said light emitter are parallel to said active region.

5. The light emitting device of claim 3, wherein at least a portion of said substrate is patterned.

6. The light emitting device of claim 1, wherein at least a portion of said light emitter comprises light extraction features.

7. The light emitting device of claim 6, wherein said light extraction features comprise texturing.

8. The light emitting device of claim 6, wherein said light extraction features comprise shaping.

9. The light emitting device of claim 1, wherein a surface of said light emitter which is adjacent to said submount has a surface area equal to or smaller than the surface area of each of the remaining surfaces of said light emitter.

10. The light emitting device of claim 1, wherein a surface of said light emitter which is adjacent to said submount is angled such that it does not form a right angle in relation to at least one of the adjacent surfaces of said light emitter.

11. The light emitting device of claim 4, wherein a surface of said light emitter which is adjacent to said submount has a smaller surface area than each of said primary emission surfaces.

12. The light emitting device of claim 1, wherein said light emitter is mounted to said submount wire bond free.

13. The light emitting device of claim 1, wherein at least a portion of said submount is reflective.

14. The light emitting device of claim 1, wherein a surface of said light emitter which is adjacent to said submount at least in part comprises a reflective material arranged such that it reflects light emitted from said light emitter.

15. The light emitting device of claim 3, wherein at least a portion of said substrate is transparent.

16. The light emitting device of claim 3, wherein at least a portion of said substrate is comprised of an electrically conductive material.

17. The light emitting device of claim 3, wherein said substrate is a growth substrate.

18. The light emitting device of claim 1 further comprising a phosphor layer disposed on at least the light emission surfaces of said light emitter.

19. The light emitting device of claim 3, wherein the primary emission surface is a surface of said LED closest to said substrate.

20. The light emitting device of claim 3, wherein the primary emission surface is a surface of said LED closest to said n-type semiconductor layer.

21. The light emitting device of claim 3, wherein the primary emission surface is a surface of said LED closest to said p-type semiconductor layer.

22. The light emitting device of claim 1, emitting a white light from said light emitting device.

23. The light emitting device of claim 1, emitting down converted light from said light emitter.

24. The light emitting device of claim 3, wherein said n-type semiconductor layer, p-type semiconductor layer, and said active region comprise materials from the Group-III Nitrides.

25. The light emitting device of claim 2, wherein said at least one LED is comprised of a plurality of interconnected sub-LEDs.

26. The light emitting device of claim 25, wherein said interconnected sub-LEDs are serially connected.

27. The light emitting device of claim 25, wherein said interconnected sub-LEDs are connected in parallel.

28. The light emitting device of claim 1 further comprising an encapsulant.

29. The light emitting device of claim 28, wherein said encapsulant comprises a phosphor region.

30. The light emitting device of claim 28, wherein said encapsulant comprises light scattering particles.

31. The light emitting device of claim 1, wherein said light emitter emits light in a Lambertian pattern.

32. The light emitting device of claim 3, wherein said n-type and p-type semiconductor layers are comprised of Group III nitride material.

33. The light emitting device of claim 6, wherein said light extraction features comprise reflective material.

34. The light emitting device of claim 1, wherein said light emitter is electrically connected via wire bonds.

35. The light emitting device of claim 34, wherein said wire bonds are connected to a side surface of said light emitter.

36. The light emitting device of claim 1, wherein said submount is comprised of a thermally conductive material.

37. A LED package, comprising:

a LED comprising a first semiconductor material, a second semiconductor material, a substrate, and an active region formed in between said first and second semiconductor materials;

a submount, wherein said LED is mounted on said submount such that the mounting surface of said LED has a surface area equal to or smaller than any one of the remaining surfaces of said LED; and

an encapsulant disposed over said LED.

38. The LED package of claim 37, wherein the primary emission surfaces of said LED are parallel to said active region.

39. The LED package of claim 38, wherein said primary emission surfaces of said LED are angled in relation to said submount.

40. The LED package of claim 37, wherein at least a portion of said LED comprises light extraction features.

41. The LED package of claim 40, wherein said light extraction features comprise texturing.

42. The LED package of claim 40, wherein said light extraction features comprise shaping.

43. The LED package of claim 37, wherein said mounting surface is angled such that it does not form a right angle in relation to at least one of the adjacent surfaces of said light emitter.

44. The LED package of claim 38, wherein said mounting surface has a smaller surface area than each of said primary emission surfaces.

45. The LED package of claim 37, wherein said LED is mounted to said submount without wire bonds.

46. The LED package of claim 37, wherein at least a portion of said submount is reflective.

47. The LED package of claim 37, wherein said LED is electrically connected by wire bonds.

48. The LED package of claim 37, wherein said mounting surface at least in part comprises a reflective material arranged such that it reflects light emitted from said light emitter.

49. The LED package of claim 37, wherein said substrate is transparent.

50. The LED package of claim 37, wherein said substrate is comprised of an electrically conductive material.

51. The LED package of claim 37, wherein said substrate is comprised of a thermally conductive material.

52. The LED package of claim 37, wherein said substrate is a growth substrate.

53. The LED package of claim 37, further comprising a phosphor layer disposed on at least the light emission surfaces of said LED.

54. The LED package of claim 37, wherein a primary emission surface is a substrate.

55. The LED package of claim 37, wherein a primary emission surface is on the side of said first semiconductor layer.

56. The LED package of claim 37, wherein a primary emission surface is on the side of said second semiconductor layer.

57. The LED package of claim 37, wherein said LED is comprised of a plurality of interconnected sub-LEDs.

58. The LED package of claim 57, wherein said interconnected sub-LEDs are serially connected.

59. The LED package of claim 57, wherein said interconnected sub-LEDs are connected in parallel.

60. The LED package of claim 37, wherein said encapsulant further comprises a phosphor region.

61. The LED package of claim 37, wherein said encapsulant further comprises light scattering particles.

62. The LED package of claim 37, wherein said LED emits light in a Lambertian pattern.

63. The LED package of claim 37, wherein said first and second semiconductor materials are comprised of a Group III Nitride material.

64. A LED package, comprising:

a LED;

a submount, wherein said LED is mounted on said submount such that the mounting surface of said LED is along the minor axis of said LED; and

an encapsulant over said LED.

65. The LED package of claim 64, wherein the primary emission surfaces of said LED are parallel to a major axis of said LED.

66. The LED package of claim 65, wherein said primary emission surfaces of said LED are angled in relation to said submount.

67. The LED package of claim 64, wherein at least a portion of said LED comprises light extraction features.

68. The LED package of claim 67, wherein said light extraction features comprise texturing.

69. The LED package of claim 67, wherein said light extraction features comprise shaping.

70. The LED package of claim 64, wherein said mounting surface is angled such that it does not form a right angle in relation to at least one of the adjacent surfaces of said light emitter.

71. The LED package of claim 65, wherein said mounting surface has a smaller surface area than each of said primary emission surfaces.

72. The LED package of claim 64, wherein said LED is mounted to said submount without wire bonds.

73. The LED package of claim 64, wherein at least a portion of said submount is reflective.

74. The LED package of claim 64, wherein said LED is electrically connected by wire bonds.

75. The LED package of claim 64, wherein said mounting surface at least in part comprises a reflective material arranged such that it reflects light emitted from said light emitter.

76. The LED package of claim 64, wherein said substrate is transparent.

77. The LED package of claim 64, wherein said substrate is comprised of an electrically conductive material.

78. The LED package of claim 64, wherein said substrate is comprised of a thermally conductive material.

79. The LED package of claim 64, wherein said substrate is a growth substrate.

80. The LED package of claim 64, further comprising a phosphor layer disposed on at least a portion of the light emission surfaces of said LED.

81. The LED package of claim 64, wherein a primary emission surface is a substrate.

82. The LED package of claim 64, wherein a primary emission surface is on the side of said first semiconductor layer.

83. The LED package of claim 64, wherein a primary emission surface is on the side of said second semiconductor layer.

84. The LED package of claim 64, wherein said LED is comprised of a plurality of interconnected sub-LEDs.

85. The LED package of claim 64, wherein said encapsulant further comprises a wavelength conversion material.

86. The LED package of claim 64, wherein said encapsulant further comprises light scattering particles.

87. The LED package of claim 64, wherein said first and second semiconductor materials are comprised of a Group III Nitride material.