Micro heatpipe integrated with LED silicon substrate

Light-emitting diodes (LEDs) offer the electric lighting market a new and revolutionary light source that saves energy and improves light quality. With the increasing illumination intensity of LEDs, thermal management became a critical issue in its design. In this paper, an LED module integrated with a micro heat pipe and heat sink was designed and fabricated. Micro grooves were fabricated on the silicon wafer to serve as micro wick. An aluminum heat sink and a glass cover plate were bonded to the wafer on the groove side respectively. Thus, the silicon wafer and the heat sink composed an integrated LED substrate, and only one thermal interface, which is chip/silicon interface, from LED chips to ambient. Thermal testing experiments were carried out to study the module's heat dissipation capability. the thermal resist of the silicon-aluminum heat pipe and heat sink had the thermal resist of 2.36 K/W and 3.01 K/W at the input power of 2.5 W and 3.0 W respectively. The effective thermal conductivity of the silicon-glass micro heat pipe was 1528.0 W/m·k. The results demonstrated that these kinds of design could average the heat produced by the LED chips to the whole device effectively and efficiently and protect the LEDs from overheating.