LAUSR

Abstract In order to shorten the accelerated aging time, it is necessary to select a reasonable thermal stress without changing the failure mechanism. In this paper, a short-cycle step-stress test is introduced to determine the stress limitation of LED, which is about 90 °C for the samples used in this work. The online method which means the lumen degradation of samples is obtained at aging condition is applied, and the error of measured luminous flux is simulated by the software of Tracepro. In data procession, the exponential fitting and Bayesian method are firstly carried out to get the lifetime and failure probability of each lamp under accelerated stress. Then the characteristic lifetime and shape parameter of samples is calculated according to Weibull distribution. Finally, the Weibull distribution curve at room temperature can be obtained by using the Arrhenius model. For the samples in this work, the correspondent lifetimes are respectively obtained to be 32,251 h with the failure probability of 63.2%. And compared with the method of Energy Star standards, it is confirmed that the method is effective.