Useful lifetime of white OLED under a constant stress accelerated life testing

A constant stress accelerated life testing has been implemented to obtain the useful lifetime of white organic light emitting displays (OLEDs) based on the lognormal distribution. However, other distributions such as Weibull and log-logistic may offer a better fit for failure time data at each stress level. The mean time to failure (MTTF) of a white OLED at each stress level will be estimated by the best fit statistical model. A response model based on an inverse power (exponential) law for all MTTFs under different stress levels is then used to predict the useful lifetime of a white OLED under normal conditions. In addition, the confidence interval of MTTF for a white OLED is provided. The results show that the MTTF of a white OLED is about 15,912 h.