Lifetime prediction of white OLED based on MLE under lognormal distribution

To predict the lifetime of a white organic light-emitting diode (OLED) and reduce test time and cost, we conducted two constant stress and one step stress accelerated lifetime tests to obtain the failure time data of samples, described the lifetime distribution of white OLED with the lognormal distribution function, estimated the log mean and log standard deviation by using maximum likelihood estimation (MLE), achieved statistics and analysis of lifetime data, and developed lifetime prediction software by ourselves. Numerical results shows that white OLED lifetime follows the lognormal distribution, that the acceleration model is consistent with inverse power law, and that the acceleration parameters, which are accurately calculated, make fast estimation of white OLED lifetime possible.