Thermally conductive LED assembly

• US 8,581,393 B2
• Filed: 06/01/2007
• Issued: 11/12/2013
• Est. Priority Date: 09/21/2006
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Meis, Michael A., Korpela, Susan L., Janssen, Jeffrey R., Hager, Patrick J., Aeling, Ellen O.
• Primary Examiner(s): Weiss, Howard
• Assistant Examiner(s): SKYLES, TIFNEY L
• Application Number:
  US11/756,929
• Publication Number:
  US 20080074871A1
• Time in Patent Office: 2,356 Days
• Field of Search: 257/294, 257/718, 257/720
• US Class Current: 257/720
• 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: F21S 4/10 with light sources attached to loose electric cables, e.g. Christmas tree lights
• CPC Class Codes: F21V 29/70 characterised by passive heat-dissipating elements, e.g. heat-sinks
• CPC Class Codes: F21V 29/74 with fins or blades
• CPC Class Codes: F21V 29/85 characterised by the material liquid coolants F21V29/56
• CPC Class Codes: F21Y 2103/10 comprising a linear 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: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: H01L 33/642 characterized by the shape

Abstract

A thermally conductive LED assembly is disclosed. The thermally conductive LED assembly includes an elongate conductor cable having a first conductor and a second conductor extending along a length of the elongate conductor cable and a thermally conducting and electrically insulating polymer layer disposed between first conductor and second conductor and a second electrically insulating polymer layer is disposed on the first conductor or second conductor. The electrically insulating polymer layer having a thermal impedance value in a range from 2.5 to 15 C.°-cm2/W and a plurality of light emitting diodes are disposed along the length of the elongate conductor cable. Each light emitting diode is in electrical communication with the first conductor and the second conductor.

Claims

1. A thermally conductive LED assembly, comprising:

an elongate flexible conductor cable having a first conductor and a second conductor, both of which extend along a length of the elongate conductor cable;

a thermally conducting and electrically insulating layer surrounding or in contact with the first conductor and the second conductor, the thermally conducting and electrically insulating layer including thermally conducting particles dispersed in a polymeric binder and having a thermal impedance value in a range from 2.5 to 15 C.°

-cm²/W;

a plurality of light emitting diodes disposed along the length of the elongate flexible conductor cable and each light emitting diode in electrical communication with the first conductor and the second conductor;

wherein the plurality of light emitting diodes emit heat and the thermally conducting and electrically insulating layer dissipates the heat along the entire length of the flexible cable.

2. A thermally conductive LED assembly according to claim 1, wherein the elongate conductor cable has a thickness and a width and a width/thickness aspect ratio of greater than 5.

3. A thermally conductive LED assembly according to claim 1, wherein the plurality of light emitting diodes are disposed along the length and a width of the elongate conductor cable, forming a two dimensional array of light emitting diodes.

4. A thermally conductive LED assembly according to claim 1, wherein the first conductor or second conductor is a patterned grid layer.

5. A thermally conductive LED assembly according to claim 1, wherein the first conductor and second conductor are patterned grid layers.

6. A thermally conductive LED assembly according to claim 1, wherein the elongate conductor cable comprises thermally conducting single walled carbon nanotubes dispersed in a polymeric binder.

7. A thermally conductive LED assembly according to claim 1, further comprising a light reflective layer disposed on a major surface of the elongate conductor cable.

8. A thermally conductive LED assembly according to claim 1, wherein the elongate conductor cable comprises a lens disposed on the plurality of LEDs.

9. A thermally conductive LED assembly according to claim 1, wherein the elongate conductor cable comprises a lens disposed on the plurality of LEDs and the lens has a thermal impedance value in a range from 2.5 to 15 C.°

-cm²/W.

10. A thermally conductive LED assembly according to claim 1, further comprising a thermally conductive adhesive layer disposed on the elongate conductor cable, and the thermally conductive adhesive layer has a thermal impedance value in a range from 2.5 to 15 C.°

-cm²/W.

11. A thermally conductive LED assembly of claim 1, wherein the thermally conducting and electrically insulating layer is one of a monolithic element or includes a plurality of layers.

12. A thermally conductive LED assembly of claim 1, further comprising:

projections or fins extending away from a major surface of the elongate conductor cable.

13. A thermally conductive LED assembly of claim 10, further comprising:

a release liner disposed on the thermally conductive adhesive layer.