A Study Of Radiating Of High-power LED And Design Of Heat Sinks

High-power white LED is a new semiconductor solid state lighting which has advantages in the following aspects: high reliability, low cost of power, high efficiency, wide applicability, quick response, changeable light color and environment friendliness. However, as the power of LED increases, LED generates more heat, and cooling gets more important. The purpose of this paper is to study the cooling of high-power LED chips and modules and to design and optimize heat sinks.Various kinds of heat sinks are designed for LED chips and an extensive numerical investigation of the heat sink design performance is conducted and verified by experiment data. The effects of heat sink structure, adhesive, heat sink materials and environment temperature are investigated.Concerning the single chip LED, the results show that, heat sinks with vertical fins have better performance than the one with parallel fins. Heat sinks with more fins lead to lower junction temperature because of larger surface. Concerning the 12 chips module, the results show that, the optimized heat spreader thickness and fin thickness are 2mm and 0.5mm respectively for Pb category heat sinks, and that the optimized inner column diameter is 7mm for Cp category heat sinks, and that the optimized inner column diameter and gap width are 10mm and 1.5mm respectively for Yp category heat sinks. Increasing the surface of heat sink leads to better thermal performance in terms of junction temperature and junction-ambient thermal resistance.It can be seen that the higher the thermal conductivity of the adhesive, the thinner the thickness of the adhesive, the higher the thermal conductivity of the heat sink materials, the lower the junction temperature and junction-ambient thermal resistance are. As the ambient temperature increases, the junction temperature increases linearly while the junction-ambient thermal resistance changes little.