Lifetime Prediction of Ultraviolet Light-emitting Diodes with Accelerated Wiener Degradation Process

The estimation of lifetime for highly reliable products including Ultraviolet Light-emitting Diodes (UV LEDs) has been challenging based on traditional lifetime tests that records time to failure. Recently constant stress and step stress degradation tests are used to gather degradation path data and modeling the degradation of performance characteristics has been applied. In this paper, a step stress accelerated degradation test (SSADT) designed to capture the degradation path and study the lifetime of UV LEDs. The radiation power degradation path was analyzed based on the IES TM-21 least square regression (LSR) and Wiener process approach. With its advantage of requiring smaller sample size and shorter test time, the SSADT provides a degradation path suitable for the proposed Wiener process modeling. The lifetime estimation for UV LEDs based on the proposed wiener process approach shows better prediction accuracy compared to the TM-21 LSR approach. By using this method, dynamic changes and degradation of the UV LEDs can be easily studied, and it can effectively estimate their remaining useful lifetimes.