An improved LED junction temperature test method based on FCM

High junction temperature (Tj) of LED will affect the performance and life of LED, so this paper proposes a high-power LED junction temperature test method. Mainly aiming at the problem that the accuracy of the forward current method (FCM) will be affected by the calibration procedure, equipment aging, and technical differences when batch testing LED Tj, this paper uses the relationship between relative current and Tj to calibrate the procedure based on this method, to limit the negative affection of sample heterogeneity. Ten LED samples were tested in the experiment, and the Tj errors under two test methods were obtained. The results showed that the improved method was more accurate than the traditional method. Then, the Tj error of the improved method was compared with that of the forward voltage method, and the error of the new method was smaller.