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Method for a carbon fiber enhanced heat-spreading strap

IP.com Disclosure Number: IPCOM000008970D
Publication Date: 2002-Jul-26
Document File: 4 page(s) / 60K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for a carbon fiber enhanced heat-spreading strap. Benefits include improved thermal performance.

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Method for a carbon fiber enhanced heat-spreading strap

Disclosed is a method for a carbon fiber enhanced heat-spreading strap. Benefits include improved thermal performance.

Background

              The requirement for heat dissipation of electronic packages keeps increasing. Typically, a limited space around the electronic package is available for the cooling device, especially for portable and hand-held devices. A conventional heat spreader is typically used to conduct the heat from the electronic package to a location with more free space to place the cooling solution, such as a heatsink. The heat spreader is commonly made of metals, such as Cu and Al due to their high thermal conductivity. However, these metals are heavy because of their density when compared to other components inside the portable and hand-held devices.

              In some cases, a flat-shape heat pipe is used to reduce the weight, but it is subject to a size limitation. Making the heat pipe thinner than 1.5 mm is very difficult. If the heat pipe is shorter than 2 inches, the heat-spreading effect of a heat pipe may be even worse than a pure metal from a thermal performance viewpoint. As a result, the heat pipe solution is difficult to implement for small portable and hand-held devices.

      Another conventional solution is a heat-spreading strap that is typically made of metals such as aluminum (180 W/m-K) and copper (390 W/m-K) that have high thermal conductivity. The strap is typically 1-mm height, 1 to 2-cm wide, and within 2-in. long. The electronic package is attached to one end of the strap, while a cooling device, such as a heatsink, is attached to the other end. The heat generated by the electronic package is conducted through the strap to the cooling device. This type of application typically occurs for cases with limited space to place the cooling device around the electronic package.

General description

              The disclosed method is a heat-spreading strap made of highly thermal-conductive carbon fibers molded with polymer. The two ends of the strap are machined to be tapered so that it can be filled with metals. The metallic heat spreader on one end can redirect the heat from its source and conduct it along the carbon-fiber direction. The metallic heat spreader on the other end collects all the heat from the carbon fiber and redirects the heat to the cooling device, such as a heatsink.

              The key elements include:

·        High-K carbon fiber with a diameter of 10 µm

·        Carbon fiber that is molded by polymer-type epoxy

·        Two tapered ends of the heat-spreading strap that are filled with metal

Advantages

              The disclosed met...