novel 3 - d super - thermal conducting heat management design and delayed cooling using phase change materials are adopted to lower the temperature inside leds and other devices . the cooling mechanism uses a fin structure with hollow fins to dissipate heat to the environment . the hollow space inside the fins is connected to an interior chamber , where a liquid to vapor phase change material is provided to transfer heat from the led chips to the surface of the hollow fins . the led chips are mounted on an evaporator located at the bottom of the chamber . a liquid reservoir is provided , and the evaporator surface is hydrophilic with an additional wick structure to transport the l - v pcm liquid to the evaporator surface . the fins are parallel to each other and are either parallel or perpendicular to the evaporator surface . this structure has superior performance and is inexpensive to manufacture .