Heat spreader for display device
View Patent ↗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.
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.