## 5 Conclusions  
Given the complex environment in which LEDs operate, this paper first proposes a multi-stress accelerated degradation evaluation method considering generalized coupling based on the traditional Arenas model. Secondly, a new gradient three-stress accelerated degradation experiment is designed to find out the coupling relationship between current, temperature, and humidity. Then, for the accuracy of the data, the life extrapolation method is not used. A multi-stress generalized coupling parameter MLE method for the entire sample is proposed, and the particle swarm algorithm is used to obtain unknown parameters to solve the multi-parameter estimation problem of the multi-stress accelerated model. Finally, it is verified that current coupling is not negligible in this LED, and the maximum error with the historical life scatter points is 6.5%, which can effectively solve the problem of poor accuracy in LED life prediction. This paper only considers one degradation failure of three-stress coupling, which is still different from the actual working conditions and has some limitations. Considering only the three stresses on LEDs as a benchmark is obviously not comprehensive enough and does not fully address potential confounding factors that may affect the reliability of the results, such as variations in LED manufacturing processes or differences in material quality, changes in humidity levels under high-temperature environments and self-heating conditions, etc. Further research and discussion are needed in tests of more stress coupling environments, such as low temperature, vibration and salt spray, and competition failure between degradation failure and accidental failure. In addition, the failure analysis of different LED materials and structures in multi-stress coupling environments is also a future development direction. Conceptualization, Z.Z. and Y.D. ; methodology, Z.Z., Y.D., and K.L. ; software, Y.D. ; validation, Y.D. and K.L. ; investigation, Z.Z. and X.Y. ; writing--original draft preparation, Y.D. ; writing--review and editing, Y.D. and X.Y. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable. The data that support the findings of this study are available from the author (Y.D.) upon reasonable request. Thanks to all of the authors cited in this article and the referees for their helpful comments and suggestions. The authors declare no conflicts of interest. * (6) [PERSON]; [PERSON] Accelerated life test of high luminosity blue LEDs. _Microelectron. Reliab._**2016**, _64_, 631-634. [CrossRef]
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