Accelerated life test of white OLED based on lognormal distribution

Abstract

In order to acquire the life information of white organic light-emitting diode (WOLED), an accelerated life test (ALT) model was established with increased working current. The lognormal distribution was applied to describe the life distribution, while the least square method (LSM) was employed to estimate the logarithm mean value and the logarithm standard deviation. Statistics and analysis on constant stress and step stress test data were performed by using the self-developed software. The numerical results show that the WOLED life is consistent with lognormal distribution and the accelerated model meets the inverse power law. The key acceleration parameter, which was calculated accurately, enables a rapid estimation of WOLED life.