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 temperature performances of the three kinds of thermal interface materials(80Au20Sn,solder paste and silver paste)of HP-LED are compared first,then the interface material thermal conductivity,the interface material thickness and the contact ratio between the interface material with the chip are simulated respectively.The results show that the rinterface thermal resistance plays an important role on the total thermal resistance of LED devices,and is one of the main factors which affect the junction temperature of LED.The simulated results show that the interface material thermal conductivity,the interface material thickness and the contact ratio of the interface material all can influence of the HP-LED junction temperature.So these three parameters should be made an overall consideration for HP-LED thermal design.