Metal encased graphite layer heat pipe

• US 10,028,418 B2
• Filed: 01/20/2015
• Issued: 07/17/2018
• Est. Priority Date: 01/20/2015
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Inventors: Nikkhoo, Michael, Hurbi, Erin
• Primary Examiner(s): DAVIS, TONY O
• Application Number:
  US14/601,088
• Publication Number:
  US 20160212888A1
• Time in Patent Office: 1,274 Days
• Field of Search: 359630, 361709
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 27/0176 characterised by mechanical features
• CPC Class Codes: G02B 7/008 with means for compensating for changes in temperature or for controlling the temperature; thermal stabilisation
• CPC Class Codes: H05K 7/20963 Heat transfer by conduction from internal heat source to heat radiating structure H05K7/20972 takes precedence

Abstract

A metal encased multilayer stack of graphite sheets used as a passive thermal conductor. In the stack, each sheet has a plane high thermal conductivity along a first axis and a plane of lower thermal conductivity along a second axis. The stack is created to have a three-dimensional shape including a length and a width, and the first axis is aligned parallel to said length, the multilayer stack having a height less than the width. A first metal structure surrounds the multilayer stack of graphite sheets, with the metal structure encasing the multilayer stack along the length, width and height of the multilayer stack.

Claims

1. An apparatus comprising:

heat producing electrical components;

a multilayer stack of graphite sheets, individual graphite sheets having a plane of high thermal conductivity along a first axis and a plane of lower thermal conductivity along a second axis, the multilayer stack having a three-dimensional shape including a length and a width, and the first axis is aligned parallel to said length, the multilayer stack having a height less than the width;

a first rigid metal structure surrounding the multilayer stack of graphite sheets, the first rigid metal structure encasing the multilayer stack along the length, width, and height of the multilayer stack; and

a thermal connector having a first end in contact with the heat producing electrical components and a second end in contact with the encased multilayer stack of graphite sheets, the thermal connector conducting heat from the heat producing electrical components to the encased multilayer stack of graphite sheets.

2. The apparatus of claim 1 wherein the individual graphite sheets are pyrolytic graphite sheets.

3. The apparatus of claim 1 wherein a metal of the first rigid metal structure is selected from one of:

aluminum, copper, silver, aluminum alloy, copper alloy, and silver alloy.

4. The apparatus of claim 1 wherein an uppermost layer in the multilayer stack and a lowermost layer in the multilayer stack contact respective upper and lower surfaces of the first rigid metal structure.

5. The apparatus of claim 1 further including a second multilayer stack of graphite sheets and second metal structure, the second metal structure bonded to the first rigid metal structure by a thermally transmissive material.

6. The apparatus of claim 1 wherein the individual graphite sheets are bonded to neighboring individual graphite sheets of the multilayer stack using an adhesive.

7. The apparatus of claim 1 wherein the individual graphite sheets are in direct mutual contact.

8. The apparatus of claim 7 wherein the first rigid metal structure creates a hermetic vacuum around the multilayer stack.

9. A wearable device, comprising:

a mounting structure including electrical components;

a multilayer stack of graphite sheets thermally bonded to the electrical components, individual graphite sheets of the multilayer stack having a higher thermal conductivity along a first axis and a lower thermal conductivity along a second axis, the multilayer stack having a three-dimensional shape including a length and a width where the first axis aligns parallel to said length, the multilayer stack having a height less than the width; and

a rigid metal structure encasing the multilayer stack to create a hermetic vacuum around the multilayer stack, the rigid metal structure encasing the multilayer stack along the length, width, and height of the multilayer stack.

10. The wearable device of claim 9 wherein the individual graphite sheets comprise pyrolytic graphite sheets.

11. The wearable device of claim 10 wherein a metal of the rigid metal structure is selected from one of:

aluminum, copper, silver, aluminum alloy, copper alloy, and silver alloy.

12. The wearable device of claim 11 wherein an uppermost layer in the multilayer stack and a lowermost layer in the multilayer stack contact respective upper and lower surfaces of the rigid metal structure encasing the multilayer stack.

13. The wearable device of claim 12, further comprising a second multilayer stack and a second metal structure encasing the second multilayer stack, the second metal structure bonded to the rigid metal structure by a thermally transmissive material.

14. The wearable device of claim 9 wherein the individual graphite sheets are bonded to respective individual graphite sheets using an adhesive.

15. The wearable device of claim 9 wherein the multilayer stack comprises a plurality of graphite sheets in direct mutual contact.

16. The wearable device of claim 9 further comprising:

a thermal connector having a first end in contact with the electrical components and a second end in contact with the rigid metal structure encasing the multilayer stack of graphite sheets, the thermal connector conducting heat from the electrical components to the rigid metal structure encasing the multilayer stack of graphite sheets.

17. A head mounted display, comprising:

electrical components comprising control circuits which produce heat;

an optical mounting structure including the heat producing electrical components, the optical mounting structure housing a display optical system coupled to the heat producing electrical components, and first and second temple arms extending away from the heat producing electrical components and the display optical system;

a metal encased multilayer stack of graphite sheets and thermally bonded to the heat producing electrical components and to an exterior surface of the optical mounting structure, each sheet of the graphite sheets having a plane high thermal conductivity along a first axis and a lower thermal conductivity along a second axis, the multilayer stack having a three-dimensional shape including a length and a width and the first axis aligns parallel to said length, the multilayer stack having a height less than the width, a metal structure encasing the multilayer stack along the length, width and height of the multilayer stack; and

a thermal connector having a first end in contact with the heat producing electrical components and a second end in contact with the metal encased multilayer stack of graphite sheets, the thermal connector conducting heat from the heat producing electrical components to the metal encased multilayer stack of graphite sheets.

18. The head mounted display of claim 17 wherein an uppermost layer in the multilayer stack and a lowermost layer in the multilayer stack contact a respective upper and lower surface of the metal structure encasing the multilayer stack.

19. The head mounted display of claim 18 wherein the multilayer stack is comprised of a plurality of sheets of pyrolytic graphite.

20. The head mounted display of claim 19 wherein the multilayer stack comprises a plurality of graphite sheets in direct mutual contact.