Study on the reliability of high-power LEDs under temperature cycle

High-power LEDs have been widely used and have a big potential market due to the many advantages compared to conventional light sources. Reliability is one of the most important issues for the application of LEDs. In order to study the degradation mechanism and the stability of LED withstanding cyclical exposures to temperature variations, life test was carried out under temperature cycle testing. The experiment was designed basing on the EIAJ ED-4701/100. Four groups of 1 W high power LEDs adopting different material and structures were utilized. The temperature cycle accelerated life test under the condition of -25°C/125°C. After the accelerated test, the optical performance of the four kinds of devices were compared and analyzed, and the thermal performance of the LEDs was also tested, analyzed and discussed. At last, the reliability differences of high-power LEDs were analyzed and degradation mechanism of high power LEDs under temperature cycling was discussed.