SOLID STATE LIGHT EMITTING DEVICE AND METHOD OF MAKING SAME

• US 20070280624A1
• Filed: 05/24/2007
• Published: 12/06/2007
• Est. Priority Date: 05/26/2006
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: LED Lighting Fixtures, Inc. (Wolfspeed, Inc.)
• Inventors: Hunter, F., Negley, Gerald
• Granted Patent: US 8,008,676 B2
• Time in Patent Office: Days
• US Class Current: 385/146
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/8592 Applying permanent coating, e.g. protective coating
• 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 33/38 with a particular shape
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating
• CPC Class Codes: H01L 33/54 having a particular shape

Abstract

There is provided a solid state light emitting device comprising at least one light emitting active layer structure and at least one structure selected from among: (1) a first element having at least a first region which has an index of refraction gradient, (2) a first element, at least a portion of which has an index of refraction which is lower than an index of refraction of a side of the active layer, (3) first and second elements, in which one side of the second element is positioned on a side of the active layer and the first element is positioned on the other side of the second element, and in which at least a portion of the first element has an index of refraction which is lower than the index of refraction of at least a portion of the second element. Also provided are methods of making such devices.

Claims

1. A solid state light emitting device comprising:

a first element, at least a first region of said first element having an index of refraction gradient; and

at least one light emitting active layer structure, said first element being positioned on said light emitting active layer structure.

2. A device as recited in claim 1, wherein said first element is in direct contact with said light emitting active layer structure.

3. A device as recited in claim 1, further comprising at least a first intervening structure positioned between said first element and said light emitting active layer structure.

4. A device as recited in claim 3, wherein said first intervening structure has an index of refraction which is similar to an index of refraction of at least a portion of said first element.

5. A device as recited in claim 3, wherein said first intervening structure has an index of refraction which is similar to an index of refraction of at least a portion of said light emitting active layer structure.

6. A device as recited in claim 3, wherein said first intervening structure comprises glue.

7. A device as recited in claim 1, wherein said index of refraction gradient of said first element comprises a stepped index of refraction gradient.

8. A device as recited in claim 1, wherein said index of refraction gradient of said first element comprises a substantially continuous index of refraction gradient.

9. A device as recited in claim 1, wherein a surface of said first element which is opposite to said light emitting active layer structure comprises at least one optical feature.

10. A device as recited in claim 1, further comprising at least one lumiphor, at least a portion of said lumiphor being positioned opposite said first element relative to said light emitting active layer structure, whereby if light is emitted from said light emitting active layer structure and passes through said first element and said lumiphor, such light would pass through said first element before passing through said lumiphor.

11. A device as recited in claim 10, wherein said lumiphor is positioned on said first element.

12. A device as recited in claim 11, wherein said lumiphor is in direct contact with said first element.

13. A device as recited in claim 10, wherein said lumiphor is spaced from said first element, at least a portion of a space between said lumiphor and said first element comprising a gas.

14. A device as recited in claim 13, wherein said gas comprises air.

15. A device as recited in claim 1, further comprising at least one encapsulant region, at least a portion of said encapsulant region being positioned opposite said first element relative to said light emitting active layer structure, whereby if light is emitted from said light emitting active layer structure and passes through said first element and said encapsulant region, such light would pass through said first element before passing through said encapsulant region.

16. A device as recited in claim 15, wherein said encapsulant region is positioned on said first element.

17. A device as recited in claim 16, wherein said encapsulant region is in direct contact with said first element.

18. A device as recited in claim 15, wherein said encapsulant region is spaced from said first element, at least a portion of a space between said encapsulant region and said first element comprising a gas.

19. A device as recited in claim 18, wherein said gas comprises air.

20. A device as recited in claim 15, further comprising at least one lumiphor, at least a portion of said lumiphor being positioned between said first element and said encapsulant region, whereby if light is emitted from said light emitting active layer structure and passes through said first element, said lumiphor and said encapsulant region, such light would pass through said first element before passing through said lumiphor and would pass through said lumiphor before passing through said encapsulant region.

21. A device as recited in claim 20, wherein said lumiphor is positioned on said first element.

22. A device as recited in claim 21, wherein said lumiphor is in direct contact with said first element.

23. A device as recited in claim 20, wherein said lumiphor is spaced from said first element, at least a portion of a space between said lumiphor and said first element comprising a gas.

24. A device as recited in claim 23, wherein said gas comprises air.

25. A device as recited in claim 1, further comprising a second element, said light emitting active layer structure having an active layer structure first side and an active layer structure second side, said first element being positioned on said active layer first side, said active layer second side being positioned on said second element.

26. A device as recited in claim 25, wherein said light emitting active layer structure is in direct contact with said second element and said first element is in direct contact with said light emitting active layer structure.

27. A device as recited in claim 25, further comprising at least one reflective element positioned between said second element and said light emitting active layer structure.

28. A device as recited in claim 27, wherein said reflective element is in direct contact with said second element, said light emitting active layer structure is in direct contact with said reflective element, and said first element is in direct contact with said light emitting active layer structure.

29. A device as recited in claim 25, further comprising at least one reflective element, said second element having a second element first side and a second element second side, said light emitting active layer being positioned on said second element first side, said reflective element being positioned on said second element second side.

30. A device as recited in claim 29, further comprising at least one bevel reflective element, said bevel reflective element being positioned on a second element third side, said second element third side extending between said second element first side and said second element second side.

31. A device as recited in claim 29, wherein said second element second side is in direct contact with said reflective element, said light emitting active layer structure is in direct contact with said second element first side, and said first element is in direct contact with said light emitting active layer structure.

32. A device as recited in claim 1, further comprising a second element, wherein said second element is positioned on said light emitting active layer structure, and said first element is positioned on said second element.

33. A device as recited in claim 32, wherein said second element is in direct contact with said light emitting active layer structure, and said first element is in direct contact with said second element.

34. A solid state light emitting device comprising:

at least one light emitting active layer structure, said light emitting active layer structure having an active layer structure first side and an active layer structure second side, a first region of said light emitting active layer structure which includes said active layer structure first side having an active layer first region index of refraction;

a first element positioned on said active layer structure first side, at least a portion of said first element having a first element index of refraction, said first element index of refraction being lower than said active layer first region index of refraction;

a second element positioned on said active layer structure second side; and

at least one lumiphor, at least a portion of said lumiphor being positioned opposite said first element relative to said light emitting active layer structure, whereby if light is emitted from said light emitting active layer structure and passes through said first element and said lumiphor, such light would pass through said first element before passing through said lumiphor.

40. A device as recited in claim 34, wherein a surface of said first element which is opposite to said light emitting active layer structure comprises at least one optical feature.

41. A device as recited in claim 34, wherein said lumiphor is positioned on said first element.

42. A device as recited in claim 41, wherein said lumiphor is in direct contact with said first element.

43. A device as recited in claim 34, wherein said lumiphor is spaced from said first element, at least a portion of a space between said lumiphor and said first element comprising a gas.

44. A device as recited in claim 43, wherein said gas comprises air.

35-39. -39. (canceled)

45. A solid state light emitting device comprising:

at least one light emitting active layer structure, said light emitting active layer structure having an active layer structure first side and an active layer structure second side, a first region of said light emitting active layer structure which includes said active layer structure first side having an active layer first region index of refraction;

a first element positioned on said active layer structure first side, at least a portion of said first element having a first element index of refraction, said first element index of refraction being lower than said active layer first region index of refraction;

a second element positioned on said active layer structure second side; and

at least one encapsulant region, at least a portion of said encapsulant region being positioned opposite said first element relative to said light emitting active layer structure, whereby if light is emitted from said light emitting active layer structure and passes through said first element and said encapsulant region, such light would pass through said first element before passing through said encapsulant region.

51. A device as recited in claim 45, wherein a surface of said first element which is opposite to said light emitting active layer structure comprises at least one optical feature.

52. A device as recited in claim 45, wherein said encapsulant region is positioned on said first element.

53. A device as recited in claim 52, wherein said encapsulant region is in direct contact with said first element.

54. A device as recited in claim 45, wherein said encapsulant region is spaced from said first element, at least a portion of a space between said encapsulant region and said first element comprising a gas.

55. A device as recited in claim 54, wherein said gas comprises air.

56. A device as recited in claim 45, further comprising at least one lumiphor, at least a portion of said lumiphor being positioned between said first element and said encapsulant region, whereby if light is emitted from said light emitting active layer structure and passes through said first element, said lumiphor and said encapsulant region, such light would pass through said first element before passing through said lumiphor and would pass through said lumiphor before passing through said encapsulant region.

57. A device as recited in claim 56, wherein said lumiphor is positioned on said first element.

58. A device as recited in claim 57, wherein said lumiphor is in direct contact with said first element.

59. A device as recited in claim 56, wherein said lumiphor is spaced from said first element, at least a portion of a space between said lumiphor and said first element comprising a gas.

60. A device as recited in claim 59, wherein said gas comprises air.

46-50. -50. (canceled)

61. A solid state light emitting device comprising:

at least one light emitting active layer structure, said light emitting active layer structure having an active layer structure first side and an active layer structure second side, a first region of said light emitting active layer structure which includes said active layer structure first side having an active layer first region index of refraction;

a first element having a first element first side and a first element second side, said first element second side being positioned on said active layer structure first side, an entirety of said first element first side being exposed, at least a portion of said first element having a first element index of refraction, said first element index of refraction being lower than said active layer first region index of refraction; and

a second element positioned on said active layer structure second side.

62. A device as recited in claim 61, wherein said first element first side is in direct contact with a space, said space comprising air.

63. A device as recited in claim 61, wherein said first element first side comprises at least one optical feature.

64. A solid state light emitting device comprising:

at least one light emitting active layer structure, said light emitting active layer structure having an active layer structure first side and an active layer structure second side, a first region of said light emitting active layer structure which includes said active layer structure first side having an active layer first index of refraction;

at least one reflective element, said reflective element having a reflective element first side and a reflective element second side, said reflective element first side being positioned on said active layer structure second side;

a first element positioned on said active layer structure first side, at least a portion of said first element having a first element index of refraction, said first element index of refraction being lower than said active layer first index of refraction; and

a second element positioned on said reflective element second side.

70. A device as recited in claim 64, wherein a surface of said first element which is opposite to said light emitting active layer structure comprises at least one optical feature.

71. A device as recited in claim 64, further comprising at least one lumiphor, at least a portion of said lumiphor being positioned opposite said first element relative to said light emitting active layer structure, whereby if light is emitted from said light emitting active layer structure and passes through said first element and said lumiphor, said light would pass through said first element before passing through said lumiphor.

72. A device as recited in claim 71, wherein said lumiphor is positioned on said first element.

73. A device as recited in claim 72, wherein said lumiphor is in direct contact with said first element.

74. A device as recited in claim 71, wherein said lumiphor is spaced from said first element, at least a portion of a space between said lumiphor and said first element comprising a gas.

75. A device as recited in claim 74, wherein said gas comprises air.

76. A device as recited in claim 64, further comprising at least one encapsulant region, at least a portion of said encapsulant region being positioned opposite said first element relative to said light emitting active layer structure, whereby if light is emitted from said light emitting active layer structure and passes through said first element and said encapsulant region, such light would pass through said first element before passing through said encapsulant region.

77. A device as recited in claim 76, wherein said encapsulant region is positioned on said first element.

78. A device as recited in claim 77, wherein said encapsulant region is in direct contact with said first element.

79. A device as recited in claim 76, wherein said encapsulant region is spaced from said first element, at least a portion of a space between said encapsulant region and said first element comprising a gas.

80. A device as recited in claim 79, wherein said gas comprises air.

81. A device as recited in claim 76, further comprising at least one lumiphor, at least a portion of said lumiphor being positioned between said first element and said encapsulant region, whereby if light is emitted from said light emitting active layer structure and passes through said first element, said lumiphor and said encapsulant region, such light would pass through said first element before passing through said lumiphor and would pass through said lumiphor before passing through said encapsulant region.

82. A device as recited in claim 81, wherein said lumiphor is positioned on said first element.

83. A device as recited in claim 82, wherein said lumiphor is in direct contact with said first element.

84. A device as recited in claim 81, wherein said lumiphor is spaced from said first element, at least a portion of a space between said lumiphor and said first element comprising a gas.

85. A device as recited in claim 84, wherein said gas comprises air.

65-69. -69. (canceled)

86. A solid state light emitting device comprising:

at least one light emitting active layer structure, said light emitting active layer structure having an active layer structure first side and an active layer structure second side, a first region of said light emitting active layer structure which includes said active layer structure first side having an active layer first index of refraction;

a first element positioned on said active layer structure first side, at least a portion of said first element having a first element index of refraction, said first element index of refraction being lower than said active layer first index of refraction;

a second element having a second element first side and a second element second side, said second element first side being positioned on said active layer structure second side; and

at least one reflective element positioned on said second element second side.

92. A device as recited in claim 86, wherein a surface of said first element which is opposite to said light emitting active layer structure comprises at least one optical feature.

93. A device as recited in claim 86, further comprising at least one lumiphor, at least a portion of said lumiphor being positioned opposite said first element relative to said light emitting active layer structure, whereby if light is emitted from said light emitting active layer structure and passes through said first element and said lumiphor, such light would pass through said first element before passing through said lumiphor.

94. A device as recited in claim 93, wherein said lumiphor is positioned on said first element.

95. A device as recited in claim 94, wherein said lumiphor is in direct contact with said first element.

96. A device as recited in claim 93, wherein said lumiphor is spaced from said first element, at least a portion of a space between said lumiphor and said first element comprising a gas.

97. A device as recited in claim 96, wherein said gas comprises air.

98. A device as recited in claim 86, further comprising at least one encapsulant region, at least a portion of said encapsulant region being positioned opposite said first element relative to said light emitting active layer structure, whereby if light is emitted from said light emitting active layer structure and passes through said first element and said encapsulant region, such light would pass through said first element before passing through said encapsulant region.

99. A device as recited in claim 98, wherein said encapsulant region is positioned on said first element.

100. A device as recited in claim 99, wherein said encapsulant region is in direct contact with said first element.

101. A device as recited in claim 98, wherein said encapsulant region is spaced from said first element, at least a portion of a space between said encapsulant region and said first element comprising a gas.

102. A device as recited in claim 101, wherein said gas comprises air.

103. A device as recited in claim 98, further comprising at least one lumiphor, at least a portion of said lumiphor being positioned between said first element and said encapsulant region, whereby if light is emitted from said light emitting active layer structure and passes through said first element, said lumiphor and said encapsulant region, such light would pass through said first element before passing through said lumiphor and would pass through said lumiphor before passing through said encapsulant region.

104. A device as recited in claim 103, wherein said lumiphor is positioned on said first element.

105. A device as recited in claim 104, wherein said lumiphor is in direct contact with said first element.

106. A device as recited in claim 103, wherein said lumiphor is spaced from said first element, at least a portion of a space between said lumiphor and said first element comprising a gas.

107. A device as recited in claim 106, wherein said gas comprises air.

87-91. -91. (canceled)

108. A solid state light emitting device comprising:

at least one light emitting active layer structure, said light emitting active layer structure having an active layer structure first side and an active layer structure second side;

a first element, at least a portion of said first element having a first element index of refraction;

a second element having a second element first side and a second element second side, said second element second side being positioned on said active layer structure first side, a first region of said second element which includes said second element first side having a second element first index of refraction;

said first element being positioned on said second element first side, said first element index of refraction being lower than said second element first index of refraction.

114. A device as recited in claim 108, wherein a surface of said first element which is opposite to said light emitting active layer structure comprises at least one optical feature.

115. A device as recited in claim 108, further comprising at least one lumiphor, at least a portion of said lumiphor being positioned opposite said first element relative to said light emitting active layer structure, whereby if light is emitted from said light emitting active layer structure and passes through said first element and said lumiphor, such light would pass through said first element before passing through said lumiphor.

116. A device as recited in claim 115, wherein said lumiphor is positioned on said first element.

117. A device as recited in claim 116, wherein said lumiphor is in direct contact with said first element.

118. A device as recited in claim 115, wherein said lumiphor is spaced from said first element, at least a portion of a space between said lumiphor and said first element comprising a gas.

119. A device as recited in claim 118, wherein said gas comprises air.

120. A device as recited in claim 108, further comprising at least one encapsulant region, at least a portion of said encapsulant region being positioned opposite said first element relative to said light emitting active layer structure, whereby if light is emitted from said light emitting active layer structure and passes through said first element and said encapsulant region, such light would pass through said first element before passing through said encapsulant region.

121. A device as recited in claim 120, wherein said encapsulant region is positioned on said first element.

122. A device as recited in claim 121, wherein said encapsulant region is in direct contact with said first element.

123. A device as recited in claim 120, wherein said encapsulant region is spaced from said first element, at least a portion of a space between said encapsulant region and said first element comprising a gas.

124. A device as recited in claim 123, wherein said gas comprises air.

125. A device as recited in claim 120, further comprising at least one lumiphor, at least a portion of said lumiphor being positioned between said first element and said encapsulant region, whereby if light is emitted from said light emitting active layer structure and passes through said first element, said lumiphor and said encapsulant region, such light would pass through said first element before passing through said lumiphor and would pass through said lumiphor before passing through said encapsulant region.

126. A device as recited in claim 125, wherein said lumiphor is positioned on said first element.

127. A device as recited in claim 126, wherein said lumiphor is in direct contact with said first element.

128. A device as recited in claim 125, wherein said lumiphor is spaced from said first element, at least a portion of a space between said lumiphor and said first element comprising a gas.

129. A device as recited in claim 128, wherein said gas comprises air.

109-113. -113. (canceled)

130. A method of making a solid state light emitting device comprising:

attaching a first element to at least one light emitting active layer structure, at least a first region of said first element having an index of refraction gradient.

133. A method as recited in claim 130, further comprising depositing said light emitting active layer structure on a second element before said attaching said first element to said light emitting active layer structure, such that said light emitting active layer structure has an active layer structure first side and an active layer structure second side, said first element is positioned on said active layer first side, and said active layer second side is positioned on said second element.

134. A method as recited in claim 130, further comprising positioning at least one lumiphor such that at least a portion of said lumiphor is opposite said first element relative to said light emitting active layer structure.

135. A method as recited in claim 134, further comprising forming at least one encapsulant region, at least a portion of said encapsulant region being positioned opposite said lumiphor relative to said light emitting active layer structure.

136. A method as recited in claim 130, further comprising forming at least one encapsulant region, at least a portion of said encapsulant region being positioned opposite said first element relative to said light emitting active layer structure.

131-132. -132. (canceled)

137. A method of making a solid state light emitting device comprising:

attaching a light emitting active layer structure on a second element, such that said light emitting active layer structure has an active layer structure first side and an active layer structure second side, a first region of said light emitting active layer structure which includes said active layer structure first side having an active layer first region index of refraction, said active layer structure second side being on said second element;

attaching a first element to said active layer structure first side, at least a portion of said first element having a first element index of refraction, said first element index of refraction being lower than said active layer first region index of refraction; and

positioning at least one lumiphor such that at least a portion of said lumiphor is opposite said first element relative to said light emitting active layer structure, whereby if light is emitted from said light emitting active layer structure and passes through said first element and said lumiphor, such light would pass through said first element before passing through said lumiphor.

138-147. -147. (canceled)

148. A method of making a solid state light emitting device comprising:

attaching a light emitting active layer structure on a second element, such that said light emitting active layer structure has an active layer structure first side and an active layer structure second side, a first region of said light emitting active layer structure which includes said active layer structure first side having an active layer first region index of refraction, said active layer structure second side being on said second element;

attaching a first element to said active layer structure first side, at least a portion of said first element having a first element index of refraction, said first element index of refraction being lower than said active layer first region index of refraction; and

positioning at least one encapsulant region such that at least a portion of said encapsulant region is opposite said first element relative to said light emitting active layer structure.

153. A method as recited in claim 148, wherein said attaching said light emitting active layer structure on said second element comprises depositing said light emitting active layer structure on said second element

154. A method as recited in claim 153, further comprising depositing said second element on at least one reflective element prior to said depositing a light emitting active layer structure on said second element, such that said reflective element and said light emitting active layer structure are positioned on opposite sides of said second element.

155. A method as recited in claim 153, further comprising depositing at least one reflective element on said second element after said depositing a light emitting active layer structure on said second element, such that said reflective element and said light emitting active layer structure are positioned on opposite sides of said second element.

149-152. -152. (canceled)

156. A method of making a solid state light emitting device comprising:

attaching at least one reflective element on a second element, such that said reflective element has a reflective element first side and a reflective element second side, said reflective element second side being on said second element;

attaching a light emitting active layer structure on said reflective element first side, such that said light emitting active layer structure has an active layer structure first side and an active layer structure second side, a first region of said light emitting active layer structure which includes said active layer structure first side having an active layer first region index of refraction, said active layer structure second side being on said reflective element first side;

attaching a first element to said active layer structure first side, at least a portion of said first element having a first element index of refraction, said first element index of refraction being lower than said active layer first region index of refraction.

157-161. -161. (canceled)

162. A method of making a solid state light emitting device comprising:

attaching a light emitting active layer structure on a second element, such that said light emitting active layer structure has an active layer structure first side and an active layer structure second side, a first region of said light emitting active layer structure which includes said active layer structure second side having an active layer first region index of refraction, said active layer structure second side being on said second element;

attaching a third element to said active layer structure first side, such that said third element has a third element first side and a third element second side, said third element second side being on said active layer structure first side;

removing said second element; and

attaching a first element to said active layer structure second side, at least a portion of said first element having a first element index of refraction, said first element index of refraction being lower than said active layer first region index of refraction.

163-167. -167. (canceled)

168. A method of making a solid state light emitting device comprising:

attaching a light emitting active layer structure on a first side of a second element, said second element comprising said first side and a second side, such that said light emitting active layer structure has an active layer structure first side and an active layer structure second side, a first region of said light emitting active layer structure which includes said active layer structure first side having an active layer first region index of refraction, said active layer structure first side being on said second element; and

attaching a first element to said second side of said second element, at least a portion of said first element having a first element index of refraction, said first element index of refraction being lower than said active layer first region index of refraction.

169. (canceled)