Influence of thermal interface material on the thermal resistance of high power LED

This work reports on the effect of employing different thermal interface materials on transient dual interface methodology for light emitting diode (LED) packages. The measurements were carried out by setting two different boundary conditions with and without thermal interface materials which were thermal paste and mylar sheets. Analysis based on structure function evaluation reveals that the exact point of separation between junction and board of an LED package can be identified using transient dual interface method. It was also observed that the total junction to ambient thermal resistance for thermal paste was less compared to mylar sheet or without any interface. For an optimum driving current of 350mA, with thermal paste as interface, the total thermal resistance and junction temperature values obtained were 12.36/W and 62.23°C respectively.