THERMALLY CONDUCTIVE LED ASSEMBLY

• US 20080074871A1
• Filed: 06/01/2007
• Published: 03/27/2008
• 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: Korpela, Susan L., Meis, Michael A., Aeling, Ellen O., Janssen, Jeffrey R., Hager, Patrick J.
• Granted Patent: US 8,581,393 B2
• Time in Patent Office: Days
• US Class Current: 362/218
• 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 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, and 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 disposed along the length of the elongate conductor cable and each light emitting diode being in electrical communication with the first conductor and the second conductor.

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

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

7. A thermally conductive LED assembly according to claim 1, wherein the elongate conductor cable comprises thermally conducting particles dispersed in a polymeric binder.

8. 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.

9. 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.

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

11. 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.

12. 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.

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

-cm²/W.

14. A method of forming a thermally conductive LED assembly, comprising:

disposing a thermally conductive and electrically insulating polymer layer between a first conductor and second conductor and disposing a second electrically insulating polymer layer on the first conductor or second conductor to form a length of an elongate conductor cable, the electrically insulating polymer layer having a thermal impedance value in a range from 2.5 to 15 C°

-cm²/W; and

placing a plurality of LEDs on the length of elongate conductor cable, wherein each LED is in electrical connection with the first conductor and the second conductor to form a thermally conductive LED assembly.

15. The method according to claim 14, further comprising combining a polymeric material with thermally conductive particles to form the thermally conductive and electrically insulating polymer layer.

16. The method according to claim 14, further comprising disposing a lens on the plurality of LEDs.

17. The method according to claim 14, further comprising disposing a pressure sensitive adhesive layer on the elongate conductor cable, the pressure sensitive adhesive layer having a thermal impedance value in a range from 2.5 to 15 C°

-cm²/W.

18. The method according to claim 14, wherein the placing step comprises placing a plurality of LEDs along the length and a width of the elongate conductor cable, forming a two dimensional array of light emitting diodes.

19. The method according to claim 14, wherein disposing step comprises disposing a thermally conductive and electrically insulating polymer layer between a first conductor patterned grid layer and a second conductor patterned grid layer to form a length of an elongate conductor cable.