Heatsinking electronic devices

• US 6,999,318 B2
• Filed: 07/28/2003
• Issued: 02/14/2006
• Est. Priority Date: 07/28/2003
• Status: Expired due to Fees

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Newby, Theodore A.
• Primary Examiner(s): DATSKOVSKIY, MICHAIL V
• Application Number:
  US10/629,374
• Publication Number:
  US 20050024834A1
• Time in Patent Office: 932 Days
• Field of Search: 361/704, 361/705, 361/712, 361717-719, 257/678, 257291-293, 257/99, 257/103, 257/75, 257/88, 257/725, 257/728, 257431-432, 257433-434, 362/227, 362/294, 362/373, 362/555, 362/800, 362/487, 362/543, 362/545, 362/382, 362/396
• US Class Current: 361/719
• CPC Class Codes: F21K 9/00 Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
• CPC Class Codes: F21V 29/763 the planes containing the fins or blades having the direction of the light emitting axis
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• 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: H05K 1/021 Components thermally connected to metal substrates or heat-sinks by insert mounting
• CPC Class Codes: H05K 1/182 associated with components mounted in the printed circuit board, e.g. insert mounted components [IMC]
• CPC Class Codes: H05K 2201/10106 Light emitting diode [LED]
• CPC Class Codes: H05K 3/0061 onto a metallic substrate, e.g. a heat sink heat sinks for electric apparatus H05K7/20

Abstract

Method and apparatus are provided for thermally coupling one or more electronic devices to a heatsink. The apparatus comprises a heatsink having a substantially planar upper surface, a wiring board (PWB) with a through-hole for receiving the device such that a principal face thereof is in thermal contact with the heatsink, its electrical leads are captured between at least a portion of the wiring board and the heatsink, and a top of the device protrudes through the PWB. The method comprises placing the device in the through-hole with its base exposed on and protruding from the underside of the PWB, attaching its electrical leads to contacts on the wiring board and pressing the PWB toward the heatsink with the leads captured there between. An electrically insulating thermally conducting layer is desirably placed between the wiring board and the heatsink.

Claims

1. An electrical optical array comprising:

a wiring board having a first plurality of openings therethrough and having first and second substantially opposite surfaces;

a second plurality of contact pads disposed on said wiring board;

a third plurality of LEDs each restrainably coupled within one of said first plurality of openings and having a third surface extending beyond said first surface and having a fourth surface exposed through said second surface;

at least one electrical lead extending from each of said third plurality of LEDs to at least one of said second plurality of contact pads; and

a heat sink thermally coupled to said third surface of each of said third plurality of LEDs and the at least one electrical lead.

2. The array of claim 1 further comprising a thermally conductive layer between the heatsink and said third surface of at least some of said third plurality of LEDs.

3. The array of claim 1 wherein the contact pads are on the first surface of the wiring board.

4. The array of claim 1 wherein the at least one electrical lead extends laterally from the LED in a general direction approximately parallel to said third surface.

5. The array of claim 3 further comprising a thermally conductive and electrically insulating layer between the at least one electrical lead of at least some of the LEDs and the heatsink.

6. An electrical assembly comprising:

an electronic device having a top, a bottom and electrical leads;

a heatsink; and

a wiring board with a through-hole for receiving the device such that the bottom of the device is in thermal contact with the heatsink, the top of the device protrudes through the wiring board, and the electrical leads of the device are positioned between and connected to a portion of the wiring board and the heatsink.

7. The assembly of claim 6 wherein the heatsink has a substantially planar upper surface and the wiring board is substantially parallel therewith.

8. The assembly of claim 6 further comprising a thermally conducting, electrically insulating resilient layer located between the electrical leads and the heatsink.

9. The assembly of claim 6 wherein the device is a surface mount semiconductor device and the elctrical leads protrude laterally therefrom between the top and bottom of the device.

10. The assembly of claim 9 wherein the electrical leads are attached to conducting regions on a lower surface of the wiring board facing toward the heatsink.

11. The assembly of claim 6 wherein the electrical leads are attached to conductive regions on an upper surface of the wiring board.

12. The assembly of claim 6 wherein the wiring board has a first portion closer to the heatsink on which are located contact regions to which the electrical leads attach and a second portion overlying the first region at least in part and wherein the electrical leads are captured between the first or second portion and the heatsink.

13. The assembly of claim 6 wherein the through hole in the wiring board has a first diameter through a first portion of the wiring board and a second diameter less than the first diameter through a second, superposed, portion of the wiring board.

14. The assembly of claim 13 wherein the first portion of the wiring board lies closer to the heatsink than the second portion.

15. The assembly of claim 13 wherein the device has a body region with an outer diameter less than the first diameter and greater than the second diameter.

17. The method of claim 11 further comprising placing an electrically insulating thermally conducting layer between the wiring board and the heatsink.

18. The method of claim 11 further comprising clamping the wiring board to the heatsink.

16. A method for forming an electrical assembly, comprising:

providing a heatsink;

providing an electronic device having a top portion, base portion and electrical leads;

providing a wiring board with electrical contact regions and a hole extending between an upper surface and a lower surface of the wiring board;

installing the device on the wiring board such its top portion is exposed from the hole on the top surface, its bottom portion protrudes from the hole beyond the bottom surface and its electrical leads are attached to the electrical contact regions of the wiring board; and

placing the lower surface of the wiring board in close proximity to the heat sink such that the bottom portion of the device is in thermal contact with the heat sink and the electrical leads of the device are positioned between and connected to a portion of the wiring board and the heat sink.