Constant-stress accelerated life test of white organic light-emitting diode based on least square method under Weibull distribution

It is currently hard to estimate the reliability parameters of organic light-emitting diodes (OLEDs) when conducting a life test at normal stress, due to the remarkably improved life of OLEDs to thousands hours. This work adopted three constant-stress accelerated life tests (CSALTs) to predict the life of white OLEDs in a short time. The Weibull function was applied to describe the life distribution, and the shape and scale parameters were estimated using the least square method. The experimental test data were statistically analyzed using a self-developed software. The life of white OLEDs predicted via this software is in good agreement with that reported from the customers. The numerical results indicated that the assumptions of CSALT are correct, and that CSALT can be used to predict the life of white OLEDs. This work confirmed that the life of white OLEDs meets the Weibull distribution, and that the accelerated life equation conforms to the inverse power law. Furthermore, the precise accelerated parameters were shown to be particularly useful in enabling the rapid estimation of white OLEDs' life.