LED lamps

• US 20060237738A1
• Filed: 06/27/2006
• Published: 10/26/2006
• Est. Priority Date: 11/19/1997
• Status: Active Grant

• Current Assignee: Epistar Corporation
• Original Assignee: Epistar Corporation
• Inventors: Salam, Hassan P. A.
• Granted Patent: US 7,947,998 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 25/0756 Stacked arrangements of devices
• 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 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/20 with a particular shape, e.g. curved or truncated substrate
• CPC Class Codes: H01L 33/38 with a particular shape
• CPC Class Codes: H01L 33/382 the electrode extending partially in or entirely through the semiconductor body
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H01L 33/64 Heat extraction or cooling elements

Abstract

A high power LED lamp has a GaN chip placed over an AlGaInP chip. A reflector is placed between the two chips. Each of the chips has trenches diverting light for output. The chip pair can be arranged to produce white light having a spectral distribution in the red to blue region that is close to that of daylight. Also, the chip pair can be used to provide an RGB lamp or a red-amber-green traffic lamp. The active regions of both chips can be less than 50 microns away from a heat sink.

Claims

1-46. -46. (canceled)

47. An LED lamp for generating incoherent visible light, comprising:

a chip, having a substrate that is light-passing to all visible light;

an inorganic semiconductor structure comprising;

an n-layer formed over the substrate, a p-layer over the n-layer, and an active region generating LED light;

p conductor spread over substantially all of the p-layer, contacting the p-layer;

a plurality of spaced metal n tracks on the semiconductor structure, each having a lower surface that feeds the n-layer;

at least one of the n tracks feeding light-generating portions of the semiconductor structure, at the n-layer, that are on opposite sides of the n track;

a pair of terminals by which the chip can be energized; and

metallic interconnection causing all light-generating parts of the chip to produce light simultaneously when a potential is applied across the pair of terminals.

48. An LED lamp according to claim 47, wherein the chip has a power rating of 1 watt or more.

49. An LED lamp according to claim 47, wherein each of said light-generating portions has surfaces that enable escape from the semiconductor structure of light emanating from the active region of the light-generating portion at an angle of 45 degrees relative to a general plane of the p-layer.

50. An LED lamp according to claim 47, wherein at least one of said n tracks is in a trench in the semiconductor structure, the trench having a side wall that is at least partly covered with light-passing non-semiconductor material.

51. An LED lamp according to claim 47, wherein said light-generating portions are electrically connected in parallel.

52. An LED lamp according to claim 47, wherein the semiconductor structure comprises a plurality of light generating sections that are electrically connected in series.

53. An LED lamp according to claim 47, including a body of fluorescent material receiving light that passes from the semiconductor structure into the substrate.

54. An LED lamp according to claim 47, including a layer of fluorescent material coating all of a lower face of the substrate.

55. An LED lamp according to claim 47, wherein the n-layer has surfaces that are inclined to a major face of the substrate, the inclined surfaces being in contact with light passing non-semiconductor material and distant from outer sides of the semiconductor structure.

56. An LED lamp according to claim 47, wherein said pair of terminals is on the chip.

57. An LED lamp according to claim 47, wherein the p-layer is one piece and extends to, or near to, four outer sides of the chip.

58. An LED lamp according to claim 47, including an elongate metal part feeding the p-layer and running between a pair of said tracks.

59. An LED lamp according to claim 58, wherein the elongate metal part and the pair of tracks are of about the same length.

60. An LED lamp according to claim 47, wherein a plurality of said n tracks are inclined to each other and meet.

61. An LED lamp according to claim 47, wherein a pair of said n tracks are oblique to each other and meet.

62. An LED lamp according to claim 47, wherein a top of the chip is next to a thermally-conductive plate, the thermally-conductive plate acting as a heat sink for the chip.

63. An LED lamp according to claim 47, wherein said p conductor comprises a light-passing conductor layer spread over substantially all of the p-layer and p tracks feeding the light-passing conductor layer.

64. An LED lamp according to claim 63, wherein said p tracks are interleaved with said n tracks.

65. An LED lamp according to claim 47, wherein said tracks comprise contact side tabs.

66. An LED lamp according to claim 47, wherein at least one of said n tracks is in a trench in the semiconductor structure, the trench extending through the p-layer and having a floor surface parallel to a major surface of the substrate.

67. An LED lamp according to claim 47, including first and second trenches in the semiconductor structure each containing an associated one of said metal n tracks, the first trench being inclined to the second trench.

68. An LED lamp for generating incoherent visible light, comprising:

a chip, having a substrate that is light-passing to all visible light;

an inorganic semiconductor structure comprising;

an n-layer formed over the substrate, a p-layer over the n-layer, and an active region generating LED light;

p conductor spread over substantially all of the p-layer, contacting the p-layer;

several spaced metal n contacts on the semiconductor structure feeding the n-layer;

at least one of the n contacts being in an associated cavity in the semiconductor structure that extends through the p-layer and feeding light-generating portions of the semiconductor structure, at the n-layer, that are on opposite sides of the n contact;

a pair of terminals by which the chip can be energized; and

metallic interconnection causing all light-generating parts of the chip to produce light simultaneously when a potential is applied across the pair of terminals.

69. An LED lamp according to claim 68, wherein for each of said n contacts there is associated conductor on the p-layer that extends from one side of the metal n contact to an opposite side of the metal n contact.

70. An LED lamp according to claim 68, wherein said associated cavity has side walls at least parts of which are in contact with light-passing dielectric material.

71. An LED lamp according to claim 68, wherein said chip has a power rating of one watt or more.

72. An LED lamp according to claim 68, wherein said associated cavity includes an associated metal part comprising one of said n contacts, the metal part extending from a bottom of the cavity to at least a top of the cavity and hugging a side wall of the cavity.

73. An LED lamp according to claim 68, wherein for at least one pair of said n contacts there is a conductor part feeding the p-layer and spanning almost all of a distance between the pair of metal n contacts.

74. An LED lamp according to claim 68, including a heat sink over the chip, for cooling the chip.

75. An LED lamp according to claim 68, wherein said pair of terminals is on the chip.

76. An LED lamp according to claim 68, wherein each of said light-generating portions has surfaces that enable escape from the semiconductor structure of light emanating from the active region of the light-generating portion at an angle of 45 degrees relative to a general plane of the p-layer.

77. An LED lamp according to claim 68, wherein most of all light escaping from the semiconductor passes out of the chip through a lower surface of the substrate.

78. An LED lamp according to claim 68, wherein the chip is between a heat sink and a layer of fluorescent material that is at the chip.

79. An LED lamp according to claim 78, wherein the obtuse angle is more than 110 degrees.

80. An LED lamp according to claim 78, wherein there is a light-passing dielectric layer on the side wall.

81. An LED lamp according to claim 80, including a metallic reflector at the dielectric layer.

82. An LED lamp according to claim 68, wherein said associated cavity has at least one side wall that is at an obtuse angle to a top of the p-layer, as measured through semiconductor.

83. An LED lamp according to claim 68, wherein the semiconductor structure has at least one surface that is oblique to a major face of the substrate and that is adjacent to dielectric material having a refractive index less than 81.3.

84. An LED lamp according to claim 68, wherein the semiconductor structure comprises a plurality of light-generating sections that are electrically connected in series.

85. An LED lamp according to claim 68, wherein there are several of said n contacts, each in an associated cavity.

86. An LED lamp for generating incoherent visible light, comprising:

a chip, having a substrate that is light-passing to all visible light;

the substrate having first and second outer sides opposite each other;

an inorganic semiconductor structure comprising;

an n-layer formed over the substrate, a p-layer over the n-layer, and an active region generating LED light;

a plurality of n metal parts on the semiconductor structure, each having an under surface feeding the n-layer, at least one of the n metal parts extending from a vicinity of the first outer side to a vicinity of the second outer side and being between light-generating portions of the semiconductor structure;

at least one p conductor on the semiconductor structure feeding the semiconductor structure at the p-layer and extending from a vicinity of the first outer side to a vicinity of the second outer side;

and wherein all light-generating parts of the chip produce light simultaneously when the lamp is turned on.

87. An LED lamp according to claim 86, including a trench in the semiconductor structure having side walls, at least parts of the side walls being covered with dielectric material.

88. An LED lamp according to claim 86, including a body of fluorescent material receiving all light from the chip.

89. An LED lamp according to claim 86, wherein the substrate has third and fourth outer sides that are opposite to each other and that meet the first and second outer sides, and wherein there is a metallic part feeding the semiconductor structure at the n-layer and extending from the vicinity of the third outer side to that of the fourth outer side.

90. An LED lamp according to claim 89, including a metallic part feeding the semiconductor structure at the p-layer and extending from a vicinity of the third outer side to a vicinity of the fourth outer side.

91. An LED lamp for generating incoherent visible light, comprising:

a chip, having a sapphire substrate;

an inorganic semiconductor structure comprising;

an n-layer formed over the substrate, a p-layer over the n-layer, and an active region generating LED light;

p conductor spread over substantially all of the p-layer, contacting the p-layer, a plane generally parallel to the p-layer defining a reference plane;

several spaced metal n contacts on the semiconductor structure, each having a lower surface feeding the n-layer;

at least one of the n contacts having light-generating portions of the semiconductor structure on opposite sides of it;

and wherein;

each of said light-generating portions has surfaces that enable escape from the semiconductor structure of light emanating from the active region of the light-generating portion at an angle of 45 degrees relative said reference plane; and

all light-generating parts of the chip produce light simultaneously when the lamp is turned on.

92. An LED lamp according to claim 91, wherein each of said light-generating portions has surfaces that are oblique to said reference plane, the oblique surfaces being in contact with light passing non-semiconductor material.

93. An LED lamp according to claim 91, including a body of fluorescent material receiving all light from the chip.

94. An LED lamp according to claim 91, including a layer of fluorescent material spanning all of a lower major face of the substrate.

95. An LED lamp according to claim 91, wherein the semiconductor structure comprises a plurality of light-generating sections that are electrically connected in series.

96. An LED lamp for generating incoherent visible light, comprising:

a chip, having a sapphire substrate;

an inorganic semiconductor structure comprising;

an n-layer formed over the substrate, a p-layer over the n-layer, and an active region generating LED light;

p conductor spread over substantially all of the p-layer, contacting the p-layer;

several spaced metal n contacts on the semiconductor structure, each having a lower surface feeding the n-layer;

at least one of the n contacts having light-generating portions of the semiconductor structure on opposite sides of it;

and wherein;

each of the light-generating portions has an associated underlying interface with the substrate and is arranged such that light rays generated in the light-generating portion and subjected to total internal reflection at the associated interface escape the semiconductor structure via the associated interface; and

all light-generating parts of the chip produce light simultaneously when the lamp is turned on.

97. An LED lamp according to claim 96, wherein the n-layer has surfaces oblique to a major face of the substrate.

98. An LED lamp according to claim 96, including metal reflectors at and parallel to said oblique surfaces.

99. An LED lamp according to claim 96, including fluorescent material receiving light from the chip.

100. An LED lamp according to claim 96, wherein the chip comprises at least one light-emitting element having a triangular-shaped top.

101. An LED lamp for generating incoherent visible light, comprising:

a chip, comprising a plurality of inorganic semiconductor light-generating elements formed on a substrate that is light-passing to all visible light, each of the elements having an anode and a cathode; and

opaque metallic connection electrically joining the cathodes of a first set of said light-generating elements to each other and to the anodes of a second set of said light-generating elements.

102. An LED lamp according to claim 101, wherein each of said elements has surfaces that are oblique to a major face of the substrate, the oblique surfaces enhancing light release form the element.

103. An LED lamp according to claim 101, wherein all of said metallic connection is on the chip.

104. An LED lamp according to claim 101, wherein said elements are between said substrate and a heat sink.

105. An LED lamp according to claim 101, including a layer of fluorescent material covering a major face of said substrate.

106. An LED lamp according to claim 101, wherein said chip comprises at least one opaque conductor track.

107. An LED lamp according to claim 106, wherein each of the light-generating elements comprises a light passing conductor.