Reliability Evaluation of LED Lamp Beads Considering Multi-Stage Wiener Degradation Process Under Generalized Coupled Accelerated Stress

LED lamp beads (hereinafter referred to as LEDs) are complex electronic components, and their degradation process shows multi-stage characteristics. Ignoring the effects of multi-stage degradation and stress coupling will lead to a higher theoretical lifespan. In this paper, a Wiener process model based on generalized coupling is proposed for the staged degradation of LEDs. This paper first conducts accelerated degradation tests on LEDs under different temperature, humidity, and current stress combinations to obtain three index parameters of LEDs. Light output performance (LOP) is selected as the degradation characteristic quantity, and the Shapiro–Wilk test is used to determine whether the parameters conform to the normal distribution. Then, the unknown parameters of the multi-stage Wiener process are estimated and a generalized coupling model is established using the unknown parameters and accelerated degradation test data. Finally, the LED life under standard stress is extrapolated based on the multiple stress acceleration factors. The analysis of LED reliability experimental data shows that the proposed method can realize reliability assessment and has higher lifetime prediction accuracy compared with the multi-stage model without considering stress coupling.