Experiments and numerical simulation on the performance of LED subjected to thermal shock

In this paper, in order to improve the reliability of LED module, the accelerated life test (ALT) for LED was conducted. Experimental measurements were adopted to obtain the temperature variations of LED module. In the experiment, the LED samples are placed in the chamber to conduct the thermal shock between -40°C and 125°C. The powered and unpowered experiments of LED were both tested. The luminous efficiency of LED was tested as a function of time. It was found that some LED samples failed. Numerical simulation was used to obtain the thermal stress distribution of the LED modules. Base on the above experiments and simulations, failure mechanisms were analyzed. The most vulnerable position of LEDs was pointed out.