Micro loop heat pipe for mobile electronics applications

Abstract

This study demonstrates a new cooling solution for the thermal management of mobile electronics. It uses a micro loop heat pipe (μLHP) with a thickness of 0.6 mm for the evaporator and 1.0 mm for the vapor line, and is designed to fit in the casing of a smartphone. We fabricated a prototype model of the μLHP by a chemical-etching and diffusionbonding process for thin copper plates. Heat from the heatgenerating components was successfully transferred by optimizing the pressure drop in the vapor and condenser lines. Thermal resistance between the μLHP's evaporator and condenser of 0.8 K/W was achieved at 5 W with an evaporator temperature of 50.5 °C for horizontal operation. We confirmed that the orientation does not significantly affect the operation of the μLHP, which is capable of transferring a heat load of up to 15 W despite different orientations.