The Effects of Void Ratio in Die Attach Layer on Optical and Thermal Performances of High Power Light Emitting Diode

In order to improve the thermal performances of high power light emitting diode (HP-LED) by the spreading thermal resistance control, the effects of void ratio in the die attach layer on HP-LED thermal properties and optical performances are studied respectively. The effects of the void ratio in the die attach layer on the thermal resistance and the spreading thermal resistance are investigated by experimental test and analytical solution respectively. The tested and the analytical results show that the spreading thermal resistance is the major component of the die attach layer thermal resistances. The tested results show that the spreading thermal resistance be obviously affected by void ratio. It increased exponentially as the index with the void ratio increase which is in accordance with the analytical results.