Heat spreader for emissive display device

• US 7,658,999 B2
• Filed: 12/18/2006
• Issued: 02/09/2010
• Est. Priority Date: 10/14/2003
• Status: Expired due to Term

• Current Assignee: NeoGraf Solutions, LLC
• Original Assignee: Graftech International Holdings Inc (Graftech International Limited)
• Inventors: Clovesko, Timothy, Smalc, Martin David, Norley, Julian, Capp, Joseph Paul
• Primary Examiner(s): Sample; David R
• Assistant Examiner(s): MILLER, DANIEL H
• Application Number:
  US11/590,115
• Publication Number:
  US 20070077434A1
• Time in Patent Office: 1,149 Days
• Field of Search: 428/408, 345/60, 185/165, 423/448, 423/447.1
• US Class Current: 428/408
• CPC Class Codes: B32B 43/006 Delaminating
• 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: H01J 2211/66 Cooling arrangements cooling or supporting means not being part of the tube H05K
• CPC Class Codes: H01J 2217/492 Details
• CPC Class Codes: H01J 7/24 Cooling arrangements; Heating arrangements; Means for circulating gas or vapour within the discharge space
• CPC Class Codes: H01J 9/20 Manufacture of screens on or from which an image or pattern is formed, picked up, converted or stored; Applying coatings to the vessel
• 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 428/1314 Contains fabric, fiber particle, or filament made of glass, ceramic, or sintered, fused, fired, or calcined metal oxide, or metal carbide or other inorganic compound [e.g., fiber glass, mineral fiber, sand, etc.]
• CPC Class Codes: Y10T 428/14 Layer or component removable to expose adhesive
• CPC Class Codes: Y10T 428/30 Self-sustaining carbon mass or layer with impregnant or other layer

Abstract

A heat spreader 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 display panel which comprises a plurality of heat sources;

b. a heat spreader having two major surface and which comprises;

i. at least one sheet of compressed particles of exfoliated graphite having two major surfaces and a density of from about 0.8 g/cc to about 2.0 g/cc, one of the major surfaces of the at least one sheet of compressed particles of exfoliated graphite having a surface area greater than the surface area of at least one of the heat sources; and

ii. a facing layer adhered to one of the major surfaces of the at least one sheet of compressed particles of exfoliated graphite for being interposed between the sheet of compressed particles of exfoliated graphite and the display panel; and

c. a layer of adhesive for adhering the heat spreader to the display panel such that substantially all of one of the major surfaces of the heat spreader is in thermal contact with the display panel, the layer of adhesive consisting of a layer of an acrylic or latex adhesive no more than about 0.015 mm in thickness, wherein the adhesive bond between the heat spreader and the display panel is stronger than the structural integrity of the at least one sheet of compressed particles of exfoliated graphite and the structure of the facing layer is stronger than the adhesive bond between the heat spreader and the display panel.

2. The display device of claim 1, wherein the display device is an emissive display device, and one of the major surfaces of the at least one sheet of compressed particles of exfoliated graphite has a surface area greater than the surface area of that part of a discharge cell facing the back surface of the emissive display device.

3. The display device of claim 2 wherein the emissive display device comprises a plasma display panel.

4. The display device of claim 3 wherein one of the major surfaces of the at least one sheet of compressed particles of exfoliated graphite has a surface area greater than the surface area of that part of a plurality of discharge cells facing the back surface of the plasma display panel.

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

6. The display device of claim 5 wherein the laminate comprises layers of a non-graphitic material.

7. The display device of claim 1 wherein the layer of adhesive achieves an average lap shear adhesion strength of at least about 700 grams per square centimeter.

8. The display device of claim 7 wherein the thickness of the layer of adhesive is no greater than about 0.015 mm.

9. The display device of claim 8 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.

10. The display device of claim 8 which further comprises a layer of adhesive interposed between the protective coating and the at least one sheet of compressed particles of exfoliated graphite.

11. The display device of claim 1 wherein at least one of the major surfaces of the at least one sheet of compressed particles of exfoliated graphite is coated with a protective coating sufficient to inhibit flaking of particles of graphite.

12. The display device of claim 11 wherein the protective coating comprises a metal or a thermoplastic material.

13. The display device of claim 12 wherein the protective coating is no more than about 0.025 mm in thickness.

14. The display device of claim 13 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.

15. The display device of claim 1 wherein the facing layer comprises a metal.