Simultaneous study of thermal and optical characteristics of light-emitting diode

This paper deals with the simultaneous study of thermal and optical behaviors of light-emitting diode (LED) through various measuring conditions. The conditions such as different types of thermal interface materials (TIMs) and increases of driving current have been selected for detailed investigation. The results revealed that the measuring conditions led to a greater impact on thermal properties than optical properties of the LED. The determined junction-to-ambient thermal resistance and junction temperature were enhanced about 1.35% and 0.78%, respectively by replacing alumina to silver thermal compound. This indicates that the application of silver thermal compound provided a slightly weaker heat transfer from the packaged LED to ambient. On the other hand, it was only 0.5% deviation on the overall optical performance was found between both the TIMs. Despite, it was observed that the increase of driving current caused an augment in optical power, and adversely decreased the efficiency of the LED. Finally, the study of real thermal resistance of the LED was performed as to improve the accuracy of the measurement.