US4267559A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low thermal impedance light-emitting diode package
Assignee: AT&T Inc
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Filing: 1979-09-24
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Granted: 1981-05-12
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Expires: 1999-09-24
Abstract
Abstract Disclosed is an assembly for relatively high power light-emitting semiconductor devices that uses simple inexpensive components and construction to provide a heat coupler that reduces the thermal impedance between the active device and the ambient atmosphere by approximately a factor of ten from that of a comparable assembly not incorporating the inventive heat coupler. The active semiconductor device is directly mounted on the heat coupler. The coupler is fabricated from material having good thermal conductivity, such as copper, copper alloys, or aluminum, and is designed to have a large surface area, at least ten times the area of the bonding surface of the active device, in unobstructed contact with the ambient atmosphere, thereby providing efficient heat coupling between the heat source and the ultimate heat sink.
Inventors
- 👤 Bertrand H. Johnson
- 👤 Carl R. Paola
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 09:12
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80; H10H20/85; H10H20/858; H10H20/8585; H10H20/8582; H10W; H10W40/00; H10W40/10; H10H20/8506; H10H20/857; H10W74/00; H10W90/00; H10W90/701; H10W90/751; H10W90/753; H10W90/754; H10W90/756
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
132 words
A light-emitting semiconductor assembly comprising (a) a header; (b) a heat coupler composed of material having a room-temperature electrical conductivity greater than 2.0·10 4 Ω -1 ·cm -1 , and a room-temperature thermal conductivity greater than 0.17 watts cm/cm 2 ·°C., the coupler having at least an external coupling surface adapted to contacting heat-dissipating means, an upper surface, and a lower surface, the header being bonded to the heat coupler at the lower surface; (c) a light-emitting semiconductor device, having a bonding surface of area not larger than 1/10 of the area of the external coupling surface of the coupler, being bonded at the bonding surface in thermally and electrically conducting relationship to the heat coupler; and (d) light transmitting means covering the light-emitting device, adapted to transmit light from the device.
Claim 2
Dependent Claim
132 words
A light-emitting semiconductor assembly comprising (a) a header; (b) a heat coupler composed of material having a room-temperature electrical conductivity greater than 2.0·10 4 Ω -1 ·cm -1 , and a room-temperature thermal conductivity greater than 0.17 watts cm/cm 2 ·°C., the coupler having at least an external coupling surface adapted to contacting heat-dissipating means, an upper surface, and a lower surface, the header being bonded to the heat coupler at the lower surface; (c) a light-emitting semiconductor device, having a bonding surface of area not larger than 1/10 of the area of the external coupling surface of the coupler, being bonded at the bonding surface in thermally and electrically conducting relationship to the heat coupler; and (d) light transmitting means covering the light-emitting device, adapted to transmit light from the device.
Claim 3
Dependent Claim
20 words
An assembly according to claim 1 wherein the light-transmitting means comprise an epoxy structure having at least one unconstrained surface.
Claim 4
Dependent Claim
23 words
An assembly according to claim 2 wherein the epoxy structure substantially covers the upper surface of the heat coupler and the light-emitting device.
Claim 5
Dependent Claim
20 words
An assembly according to claim 3 wherein an epoxy-conformal layer is interposed between the epoxy structure and the light-emitting device.
Claim 6
Dependent Claim
135 words
A light-emitting diode assembly comprising (a) a header; (b) a heat coupler composed of material having a room temperature electrical conductivity greater than 2.0·10 4 Ω -1 ·cm -1 , and a room temperature thermal conductivity greater than 0.17 watts·cm/cm 2 ·°C., the coupler having at least an external coupling surface adapted to contacting heat-dissipating means, an upper surface, and a lower surface, the header being bonded to the heat coupler at the lower surface; (c) a light-emitting semiconductor diode, having a bonding surface of area not larger than 1/10 of the area of the external coupling surface of the coupler, the diode being bonded at the bonding surface in electrically and thermally conducting relationship to the heat coupler; and (d) light-transmitting means covering the light-emitting diode, adapted to transmitting light from the light-emitting diode.
Claim 7
Dependent Claim
135 words
A light-emitting diode assembly comprising (a) a header; (b) a heat coupler composed of material having a room temperature electrical conductivity greater than 2.0·10 4 Ω -1 ·cm -1 , and a room temperature thermal conductivity greater than 0.17 watts·cm/cm 2 ·°C., the coupler having at least an external coupling surface adapted to contacting heat-dissipating means, an upper surface, and a lower surface, the header being bonded to the heat coupler at the lower surface; (c) a light-emitting semiconductor diode, having a bonding surface of area not larger than 1/10 of the area of the external coupling surface of the coupler, the diode being bonded at the bonding surface in electrically and thermally conducting relationship to the heat coupler; and (d) light-transmitting means covering the light-emitting diode, adapted to transmitting light from the light-emitting diode.
Claim 8
Dependent Claim
20 words
An assembly according to claim 5 wherein the light-transmitting means comprise an epoxy structure having at least one unconstrained surface.
Claim 9
Dependent Claim
23 words
An assembly according to claim 6 wherein the epoxy structure substantially covers the upper surface of the heat coupler and the light-emitting diode.
Claim 10
Dependent Claim
20 words
An assembly according to claim 7 wherein an epoxy-conformal layer is interposed between the epoxy structure and the light-emitting diode.
Claim 11
Dependent Claim
13 words
An assembly according to claim 5 wherein the header is a TO-18 header.
Claim 12
Dependent Claim
14 words
An assembly according to claim 9 wherein the heat coupler comprises a copper alloy.
Claim 13
Dependent Claim
33 words
An assembly according to claim 10 wherein the light-transmitting means consists substantially of epoxy substantially covering the upper surface of the heat coupler and the diode, the light-transmitting means having an unconstrained surface.
Claim 14
Dependent Claim
143 words
A light-emitting semiconductor diode assembly comprising (a) a TO-18 header; (b) a heat coupler comprising a copper alloy, the coupler having substantially cylindrical shape, with an upper and a lower surface, and a peripheral coupling surface, the header being bonded to the coupler at the lower surface of the coupler; (c) a light-emitting semiconductor diode chip, having a bonding surface of area not larger than 1/10 of the area of the peripheral coupling surface of the coupler, the diode being bonded at the bonding surface in electrically and thermally conducting relationship to the upper surface of the heat coupler; (d) an epoxy structure adapted to transmitting light from the diode chip, substantially covering the upper surface of the heat coupler and the diode chip, and having an unconstrained surface; and (e) an epoxy-conformal layer interposed between the epoxy structure and the diode chip.
Claim 15
Dependent Claim
143 words
A light-emitting semiconductor diode assembly comprising (a) a TO-18 header; (b) a heat coupler comprising a copper alloy, the coupler having substantially cylindrical shape, with an upper and a lower surface, and a peripheral coupling surface, the header being bonded to the coupler at the lower surface of the coupler; (c) a light-emitting semiconductor diode chip, having a bonding surface of area not larger than 1/10 of the area of the peripheral coupling surface of the coupler, the diode being bonded at the bonding surface in electrically and thermally conducting relationship to the upper surface of the heat coupler; (d) an epoxy structure adapted to transmitting light from the diode chip, substantially covering the upper surface of the heat coupler and the diode chip, and having an unconstrained surface; and (e) an epoxy-conformal layer interposed between the epoxy structure and the diode chip.
Claim 16
Dependent Claim
33 words
An assembly according to claims 1, 5 or 12 wherein the lower surface of the heat coupler has an indented portion, with the indented portion fitting over at least part of the header.
References Cited (Backward Citations)
US3299331A
Cited
US3458779A
Cited
US3510732A
Cited
US3614550A
Cited
US3805347A
Cited
US4003074A
Cited
US3867666A
Cited
US4032963A
Cited
US4131911A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-05-11 | 1984-11-10 | 1985-05-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-05-11 | 1988-11-10 | 1989-05-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-05-11 | 1992-11-10 | 1993-05-12 | $7700.00 | Window Closed / Lapsed |