Heat spreader with thermally coductive foam core

• US 9,813,082 B2
• Filed: 10/08/2015
• Issued: 11/07/2017
• Est. Priority Date: 10/08/2015
• Status: Active Grant

• Current Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Inventors: Bai, Mo, Gektin, Vadim
• Primary Examiner(s): Nguyen, Duc M
• Application Number:
  US14/878,894
• Publication Number:
  US 20170104500A1
• Time in Patent Office: 761 Days
• Field of Search: 36167946, 36167952, 36167954, 361688, 361696, 361697, 361702, 361709, 361714-724, 16510411
• CPC Class Codes: F28F 13/003 by using permeable mass, perforated or porous materials F28F13/18 takes precedence
• CPC Class Codes: G06F 1/20 Cooling means
• CPC Class Codes: H01L 23/34 Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements thermal treatment apparatus H01L21/00
• CPC Class Codes: H01L 23/3672 Foil-like cooling fins or heat sinks being part of lead-frames H01L23/49568
• CPC Class Codes: H04B 1/036 Cooling arrangements
• CPC Class Codes: H05K 7/2039 characterised by the heat transfer by conduction from the heat generating element to a dissipating body arrangements for increasing/decreasing heat-transfer, e.g. fins details, F28F13/00
• CPC Class Codes: H05K 7/20854 Heat transfer by conduction from internal heat source to heat radiating structure H05K7/20863 takes precedence

Abstract

A heat spreader and a method for making a heat spreader are disclosed. In an embodiment the heat spreader includes an enclosure with a hollow core and a foam core located in the hollow core.

Claims

1. A remote radio unit (RRU) comprising:

a rear side of the RRU comprising a base plate and sidewalls;

a single cover for the RRU, the cover covering the rear side, wherein the rear side and the cover form an outside of the RRU and enclose an inside; and

electronic transceiver circuitry located in the inside of the RRU,

wherein the cover, the base plate or the sidewalls includes an enclosure with a hollow core formed within the cover, the base plate or the sidewalls, and

wherein a foam core that comprises pores or voids is disposed and sealed within the hollow core formed within the cover, the base plate or the sidewalls.

2. The remote radio unit according to claim 1, wherein the enclosure comprises a solid thermally conductive material with an average weight of less than 5 mg per mm³ and an average thermal conductivity of more than 150 W per (m*K), and wherein the foam core comprises an average weight of less than 4 mg per mm³ and an average thermal conductivity of more than 100 W per (m*K).

3. The remote radio unit according to claim 1, wherein the enclosure comprises a solid thermally conductive material with an average weight between 2 mg per mm³ and 3.5 mg per mm³ and an average thermal conductivity between 150 W per (m*K) and 300 W per (m*K), and wherein the foam core comprises an average weight between 1.5 mg per mm³ and 2.5 mg per mm³ and an average thermal conductivity between 100 W(m*K) and 200 W(m*K).

4. The remote radio unit according to claim 1, wherein the enclosure comprises aluminum.

5. The remote radio unit according to claim 4, wherein the enclosure comprises elemental aluminum.

6. The remote radio unit according to claim 4, wherein the foam core comprises aluminum.

7. The remote radio unit according to claim 6, wherein the foam core comprises elemental aluminum.

8. The remote radio unit according to claim 1, wherein the foam core comprises a three dimensional matrix structure having matrix elements and the pores or the voids.

9. The remote radio unit according to claim 8, wherein the matrix elements comprise a thermally conductive material and the pores or voids comprise air.

10. A remote radio unit (RRU) comprising:

a rear side of the RRU comprising a base plate and sidewalls;

a single cover for the RRU, the cover covering the rear side, wherein the rear side and the cover form an outside of the RRU and enclose an inside; and

electronic transceiver circuitry located in the inside of the RRU,

wherein the base plate, the sidewalls, or the cover form(s) a hollow base plate, hollow sidewalls or a hollow cover, and wherein a foam core, which comprises pores or voids, is disposed and sealed within the hollow base plate, the hollow sidewalls or the hollow cover.

11. The remote radio unit according to claim 10, wherein the cover comprises cooling fins, wherein the cooling fins are of a solid material, and wherein a material of the solid material is the same as a material of the hollow cover.

12. The remote radio unit according to claim 10, wherein the foam core comprises a three dimensional matrix structure having matrix elements and the pores or the voids.

13. The remote radio unit according to claim 12, wherein the matrix elements comprise a thermally conductive material and the pores or the voids comprise air.

14. The remote radio unit according to claim 12, wherein the matrix elements comprise a thermally conductive material and the pores or the voids comprise an inert gas.

15. The remote radio unit according to claim 12, wherein the hollow cover comprises a solid thermally conductive material with an average weight of less than 5 mg per mm³ and an average thermal conductivity of more than 150 W per (m*K), and wherein the foam core comprises an average weight of less than 4 mg per mm³ and an average thermal conductivity of more than 100 W per (m*K).