Takashi Yajima

Thermal performance of novel thin heat pipe

Consumer electronics, as exemplified by LCD TVs and notebook PCs, continue to become thinner and smaller. At the same time, the demand for cooling of high heat-generating large scale integrations in a thin and small space becomes ever stronger. We developed a thin yet low heat-resistant thermal transport device that meets these requirements, and we present our findings here. Our device, a thin heat pipe, is a mere 1.3- mm thick, yet it has a power capacity of 63 W for a 40 ÷ 200 mm device, for example, or the equivalent to thermal conductivity of 10,000 W/mk.(The orientation of the device is horizontal. And heat flux is 5.3W/cm2.) The thin heat pipe is constructed of two machined copper plates bonded together to form the body, with a wick bonded internally. The properties of the thin heat pipe can be estimated by calculation. The power capacity is calculated from the balance between capillary force and each type of flow path resistance. The equivalent thermal conductivity is calculated by taking into consideration the flow path resistance of the gas phase and the drop in temperature due to the effect of the condensation sections non-condensable gas. For the flow path resistance of the liquid phase and gas phase, as well as capillary force, actual measurements can be done at each state.