Thermal design of a ultra-slim notebook computer

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