Research on thermal shock test for the optical and electrical properties of white LEDs

The objective of this paper is to investigate the optical and electrical properties of white LED chips changes in the thermal shock test process. In the experiment, we used a high-frequency electromagnetic heating equipment to carry out the thermal shock test, and the Cree-Xlamp-Mx-6 white LED chips were used as samples. We designed a set of experiments, putting the non-operating chips on the working table, enduring from 40°C to 150°C rapid alternating heating and cooling cycles in 10s. ANSYS software was used to simulation the temperature variation on LED chips surface and integrating sphere device was employed to measure the key optical and electrical parameters change with the aging time, including luminous efficiency, luminous flux, correlated color temperature, peak wavelength, color rendering index, forward voltage and then analyzed the failure mechanism.