热界面材料对高功率LED热阻的影响

散热不良是制约大功率LED发展的主要瓶颈之一, 直接影响着大高功率LED器件的寿 命、出光效率和可靠性等。本文采用T3ster热阻测试仪和 ANSYS热学模拟的方法对LED器件进行热学分析,以三种热界面材料(金锡,锡膏,银胶)对LE D热阻及芯片结温的影响为例,分析了热界面材料的热导率、厚度对LED器件热学性能的影响 ,实验结果表明界面热阻在LED器件总热阻中所占比重较大,是影响LED结温高低的主要因素 之一；热学模拟结果表明,界面材料的热导率、厚度及界面材料的有效接触率均会影响到LE D器件结温的变化,所以在LED器件界面互连的设计中,需要综合考虑以上三个关键参数的控 制,以实现散热性能最佳化。

Influence of thermal interface material on high power LED thermal resistance

Heat dissipation is one of the bottlenecks which affect the life time, luminous efficiency and reliability of LED devices.This is also the reason reson restrict the development of high power LED devices.Thermal analysis was carried out by combining T3ster thermal resistance tester with ANSYS simulation.The thermal resistance and junction temp erature performances of the three kinds of thermal interface materials(80Au 20Sn,solder paste and silver paste) of HP-LED are compared first,then the interface material thermal conduc tivity,the interface material thickness and the contact ratio between the interf ace material with the chip are simulated respectively.The results show that the rinterface thermal resistance plays an important role on the total thermal resis tance of LED devices,and is one of the main factors which affect the junction te mperature of LED.The simulated results show that the interface material thermal conductivity,the interface material thickness and the contact ratio of the inter face material all can influence of the HP-LED junction temperature.So these thr ee parameters should be made an overall consideration for HP-LED thermal design .