Heat spreader for display device

• US 7,276,273 B2
• Filed: 09/29/2004
• Issued: 10/02/2007
• Est. Priority Date: 10/14/2003
• Status: Active Grant

• Current Assignee: NeoGraf Solutions, LLC
• Original Assignee: Advanced Energy Technology Inc. (Graftech International Limited)
• Inventors: Smalc, Martin David, Clovesko, Timothy, Norley, Julian, Capp, Joseph Paul
• Primary Examiner(s): Nordmeyer; Patricia L
• Application Number:
  US10/953,917
• Publication Number:
  US 20050142317A1
• Time in Patent Office: 1,098 Days
• Field of Search: 428/40.1, 428/141, 428/143, 428/323, 428/408, 423/448, 257/707, 257751-756, 313 44- 47, 313/493, 313/634, 313/581, 313/582, 313/587, 165/185, 361/704
• US Class Current: 428/40.1
• CPC Class Codes: B32B 2307/302 Conductive
• CPC Class Codes: B32B 2457/20 Displays, e.g. liquid crystal displays, plasma displays
• CPC Class Codes: B32B 7/12 using interposed adhesives or interposed materials with bonding properties
• CPC Class Codes: B32B 9/00 Layered products comprising a layer of a particular substance not covered by groups B32B11/00 - B32B29/00
• CPC Class Codes: B32B 9/007 comprising carbon, e.g. graphite, composite carbon
• CPC Class Codes: B32B 9/041 of metal
• CPC Class Codes: B32B 9/045 of synthetic resin
• CPC Class Codes: G06F 1/1601 Constructional details related to the housing of computer displays, e.g. of CRT monitors, of flat displays constructional details related to flat displays integrated in a portable computer, e.g. laptop, handheld computer G06F1/1637; constructional details related to television receivers H04N5/64
• CPC Class Codes: G06F 1/20 Cooling means
• CPC Class Codes: G06F 2200/1612 Flat panel monitor
• CPC Class Codes: H01J 2211/66 Cooling arrangements cooling or supporting means not being part of the tube H05K
• CPC Class Codes: H01L 23/367 Cooling facilitated by shape of device H01L23/38, H01L23/40, H01L23/42, H01L23/44, H01L23/46 take precedence
• 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 7/20963 Heat transfer by conduction from internal heat source to heat radiating structure H05K7/20972 takes precedence
• CPC Class Codes: Y10T 428/14 Layer or component removable to expose adhesive
• CPC Class Codes: Y10T 428/1438 Metal containing
• CPC Class Codes: Y10T 428/30 Self-sustaining carbon mass or layer with impregnant or other layer

Abstract

A heat spreader (10) for a display device, such as a plasma display panel, a light emitting diode or a liquid crystal display, comprising at least one sheet of compressed particles of exfoliated graphite having a surface area greater than the surface area of that part of the back surface of the display device where a localized region of higher temperature is generated.

Claims

1. A display device, comprising:

a. a liquid crystal display device which comprises a plurality of heat sources; and

b. a heat spreader which comprises at least one sheet of compressed particles of exfoliated graphite having two major surfaces, the heat spreader having a surface area greater than the surface area of that part of the back surface of the display device where a localized region of higher temperature is generated, wherein substantially all of one of the major surfaces of the heat spreader is in thermal contact with the liquid crystal display device and further wherein the heat spreader itself reduces the temperature difference between locations on the display device.

2. The display device of claim 1 wherein the heat spreader comprises a laminate comprising a plurality of sheets of compressed particles of exfoliated graphite.

3. The display device of claim 2 wherein the laminate comprises layers of a non-graphitic material.

4. The display device of claim 1 wherein the heat spreader comprises an adhesive thereon and a release material positioned such that the adhesive is sandwiched between the heat spreader and the release material.

5. The display device of claim 4 wherein the release material and adhesive are selected to permit a predetermined rate of release of the release material without causing undesirable damage to the heat spreader.

6. The display device of claim 5 wherein the adhesive and release material provide an average release load of no greater than about 40 grams per centimeter at a release speed of one meter per second.

7. The display device of claim 6 wherein the adhesive achieves a minimum lap shear adhesion strength of at least about 125 grams per square centimeter.

8. The display device of claim 7 wherein the adhesive achieves an average lap shear adhesion strength of at least about 700 grams per square centimeter.

9. The display device of claim 8 wherein the thickness of the adhesive is no greater than about 0.015 mm.

10. The display device of claim 9 wherein the at least one sheet of compressed particles of exfoliated graphite has edge surfaces, and at least one edge surface is coated with a protective coating sufficient to inhibit flaking of the particles of graphite.

11. The display device of claim 9 which further comprises a layer of adhesive interposed between the protective coating and the at least one sheet of compressed particles of exfoliated graphite.

12. The display device of claim 1 wherein at least one of the major surfaces of the heat spreader is coated with a protective coating sufficient to inhibit flaking of particles of graphite.

13. The display device of claim 12 wherein the protective coating comprises a metal or a thermoplastic material.

14. The display device of claim 13 wherein the protective coating is no more than about 0.025 mm in thickness.

15. The display device of claim 14 wherein the protective coating is effective to electrically isolate the coated major surface of the at least one sheet of compressed particles of exfoliated graphite.

16. The display device of claim 1 which further comprises a facing layer adhered to a surface thereof for being interposed between the sheet of compressed particles of exfoliated graphite and the display device.

17. The display device of claim 16 wherein the facing layer comprises a metal.