Heat spreader for display device

• US 7,303,820 B2
• Filed: 01/28/2005
• Issued: 12/04/2007
• Est. Priority Date: 10/14/2003
• Status: Expired due to Fees

• Current Assignee: NeoGraf Solutions, LLC
• Original Assignee: Graftech International Holdings Inc (Graftech International Limited)
• Inventors: Reis, Bradley E., Smalc, Martin David, Clovesko, Timothy, Norley, Julian, Capp, Joseph P.
• Primary Examiner(s): McNeil; Jennifer C.
• Assistant Examiner(s): Miller; Daniel
• Application Number:
  US11/045,457
• Publication Number:
  US 20060098413A1
• Time in Patent Office: 1,040 Days
• Field of Search: 428/408, 345/60, 185/165, 423/448
• US Class Current: 428/408
• CPC Class Codes: B32B 2250/42 Alternating layers, e.g. ABAB(C), AABBAABB(C)
• CPC Class Codes: B32B 2264/108 Carbon, e.g. graphite particles
• CPC Class Codes: B32B 2266/0207 Materials belonging to B32B25/00
• CPC Class Codes: B32B 2307/302 Conductive
• CPC Class Codes: B32B 2307/748 Releasability
• CPC Class Codes: B32B 2457/20 Displays, e.g. liquid crystal displays, plasma displays
• CPC Class Codes: B32B 5/16 characterised by features of a layer formed of particles, e.g. chips, powder or granules layer formed of natural mineral particles B32B19/00; layer being formed of wood fibres, chips or particles B32B21/02
• CPC Class Codes: B32B 5/18 characterised by features of a layer of foamed material
• CPC Class Codes: B32B 5/22 characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed layer formed of natural mineral fibres or particles next to a foam layer B32B19/047, next to a layer made of particles B32B19/048, or next to a fibrous or filamentary layer B32B19/06; paper layer or cardboard layer next to a paper layer or cardboard layer B32B29/005, next to a foam layer B32B29/007, next to a fibrous or filamentary layer B32B29/02, or next to a particulate layer B32B29/04
• CPC Class Codes: B32B 5/30 one layer being formed of particles, e.g. chips, granules, powder
• 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: H01J 2217/492 Details
• 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 428/30 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, which includes at least one sheet of compressed particles of exfoliated graphite having two major surfaces, both of which have a layer of an adhesive thereon.

Claims

1. A heat spreader for a display device, comprising at least one sheet of compressed particles of exfoliated graphite having two major surfaces, each of the major surfaces having a layer of an adhesive material thereon, wherein the heat spreader further comprises a biasing material which comprises a foam and which forces the heat spreader against a display device to which the heat spreader is applied in response to pressure applied to the biasing material by the structural chassis of the display device, to increase thermal contact between the heat spreader and the display device.

2. The heat spreader of claim 1 wherein the surface area of one of the major surfaces of the spreader is greater than the surface area of that part of the back surface of a display device where a localized region of higher temperature is generated.

3. The heat spreader of claim 2, wherein the display device is an emissive display device, and 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.

4. The heat spreader of claim 3 wherein the emissive display device comprises a plasma display panel.

5. The heat spreader of claim 4 wherein 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.

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

7. The heat spreader of claim 6 wherein the laminate comprises layers of a non-graphitic material.

8. The heat spreader of claim 1 wherein the heat spreader comprises a release material positioned on each major surface thereof such that the adhesive on each major surface is sandwiched between the at least one sheet of compressed particles of exfoliated graphite and the release material.

9. The heat spreader of claim 8 wherein the adhesive on each major surface thereof achieves a minimum lap shear adhesion strength of at least about 125 grams per square centimeter.

10. The heat spreader of claim 9 wherein the adhesive on each major surface thereof achieves an average lap shear adhesion strength of at least about 700 grams per square centimeter.

11. The heat spreader of claim 10 wherein the thickness of the adhesive on at least one of the major surfaces of the at least one sheet of compressed particles of exfoliated graphite is no greater than about 0.015 mm.

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

20. The heat spreader of claim 1 wherein the foam comprises a material selected from the group consisting of rubber foams, silicone foams, filled silicone foams, or combinations thereof.

21. The heat spreader of claim 20 which further comprises a layer of adhesive on the surface of the biasing material facing away from the at least one sheet of compressed particles of exfoliated graphite.

13. A heat spreader for a display device, comprising at least one sheet of compressed particles of exfoliated graphite having two major surfaces, at least one of the major surfaces having a layer of an adhesive material thereon, one of the major surfaces further having a biasing material having two major surfaces adhered thereto such that a first major surface of the biasing material is adhered to the at least one sheet of compressed particles of exfoliated graphite, wherein the biasing material comprises a foam and forces the heat spreader against a display device to which it is applied in response to pressure applied to the biasing material by the structural chassis of the display device, to increase thermal contact between the heat spreader and the display device.

14. The heat spreader of claim 13 wherein the foam comprises a material selected from the group consisting of rubber foams, silicone foams, filled silicone foams, or combinations thereof.

15. The heat spreader of claim 13 which further comprises a layer of adhesive on the surface of the biasing material facing away from the at least one sheet of compressed particles of exfoliated graphite.

16. The heat spreader of claim 13, wherein the display device is an emissive display device, and 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.

17. The heat spreader of claim 13 wherein the heat spreader comprises a laminate comprising a plurality of sheets of compressed particles of exfoliated graphite.

18. The heat spreader of claim 17 wherein the laminate comprises layers of a non-graphitic material.

19. The heat spreader of claim 13 which further comprises at least one sheet of compressed particles of exfoliated graphite having two major surfaces adhered to the second major surface of the biasing material.

22. A display device, comprising:

(a) a display device having a structural chassis;

(b) a heat spreader applied to the display device, wherein the heat spreader comprises at least one sheet of compressed particles of exfoliated graphite having two major surfaces, at least one of the major surfaces having a layer of an adhesive material thereon, one of the major surfaces further having a biasing material having two major surfaces adhered thereto such that a first major surface of the biasing material is adhered to the at least one sheet of compressed particles of exfoliated graphite, wherein the biasing material comprises a foam and forces the heat spreader against the display device in response to pressure applied to the biasing material by the structural chassis, for greater thermal contact.

23. The display device of claim 22 wherein the foam comprises a material selected from the group consisting of rubber foams, silicone foams, filled silicone foams, or combinations thereof.

24. The display device of claim 22 which further comprises a layer of adhesive on the surface of the biasing material facing away from the at least one sheet of compressed particles of exfoliated graphite.

25. The display device of claim 22, wherein the display device is an emissive display device, and 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.

26. The display device of claim 22 wherein the heat spreader comprises a laminate comprising a plurality of sheets of compressed particles of exfoliated graphite.

27. The display device of claim 26 wherein the laminate comprises layers of a non-graphitic material.

28. The display device of claim 22 which further comprises at least one sheet of compressed particles of exfoliated graphite having two major surfaces adhered to the second major surface of the biasing material.