US Patent 8074706 Heat spreader with composite micro-structure

A heat spreader comprising a casing, a micro-structure layer, a support device, and a working fluid is provided. The casing has an inner surface and is defined by a sealed chamber where the working fluid circulates therein. The micro-structure layer is formed on the inner surface of the casing, wherein the micro-structure layer comprises a first structure layer which is formed by the first metallic mesh. Specifically, the first metallic mesh forms the first structure layer on the inner surface through diffusion bonding so that the working fluid can circulate within the micro-structure layer by capillary action. In addition, the support device is disposed in the sealed chamber for supporting the casing. Thus, a heat spreader with a composite micro-structure can not only enhance the capillarity but also reduce the flowing resistance during operation.