Degradation model of LED based on accelerated life test

Abstract

ALT(accelerated life test) is a right choice to predict the lifetime of LED lighting source that is expected to have much longer lifetime than the conventional lighting sources. Middle power light-emitting diode (LED) accelerated life tests(ALT) were carried out by two kind of test methods (LED PKG level ALT and LED PKG component (chip, phosphor, premold) level ALT). The predicted curve by using component ALT model contained an inflection point caused by degradation characteristics of PKG component (premold). Therefore, we expect that component accelerated model is more accurate and more logical than simple extrapolation methods as used by LM80 and TM21.