Cause analysis on highly depreciated indoor LED product in CSA020

With application of accelerated luminous depreciation test method of CSA020 which can reduce the lifetime test from 6,000 hours to less than 2,000 hours, LED lighting products with highly lumen depreciation or short lifetime can be easily screened out. Many potential factors can lead to that highly depreciation issue. This paper attempted to perform highly depreciation cause analysis by investigation on the activation energy Ea and junction temperature Tj of the highly depreciation of indoor LED products. Results were shown Ea of Product 4 is 0.29eV, even 0.09eV lower than the reference good product. Junction temperature Tj of Product 4 is 109deg.C, around 30deg.C higher than the reference good product, which means the junction temperature Tj is a key factor which caused highly depreciation. During lifetime design, both Ea and Tj are important and should be considered equally.