White LED light emission as a function of current and junction temperature

The performance of white LED is highly dependent on the current effect and thermal effect. In this work, a measurement equipment is designed and set up to study the relationships among light output, current and junction temperature by controlling the junction temperature. Results revealed that the luminous flux increases nonlinearly with increasing current and decreases as junction temperature increases. Moreover, we presented an integrated model which links the photometric, electrical, and thermal aspects of an LED based on the results of experiment. This model verified by a LED without any thermal control can explain why the LED has a maximum luminous flux and how to obtain the higher current saturation point of luminous flux.