Thermal design of an ultraslim notebook computer

We have developed two innovative thermal solutions for ultraslim notebook personal computer (PC) where only natural convection cooling can be used for heat rejection. The first solution is a cooling system for the CPU using the bottom chassis (Mg die-cast) as a heat spreader combining with Al heat transfer plate. The size and geometry were optimized by thermal analysis using finite volume method before making the prototype. As the second solution, a new coating which can reduce the warmth of Mg (magnesium alloy) die-cast enclosure has been developed and has already reached the stage of practical use. This paper describes the outline of these thermal design technologies used for Mitsubishi ultraslim notebook PC "Pedion." As of September 1997 "Pedion" was the world's thinnest at 18 mm thick among A4-size notebook computers for Microsoft(R) Windows(R).