Application of accelerated life testing principles to project long term lumen maintenance of LED luminaires

Abstract

This work presents our effort to predict the long term reliability of LED arrays using the application of accelerated life testing principles. Assessment of long term reliability and performance of LED arrays is a testing exercise but it is also vital for successful acceptance of Solid State Lighting (SSL) systems. The objective of this work is to analyze IESNA LM-80 test data obtained from the LED manufacturers to study how failure is accelerated by stress and fit an acceleration model to the data. This acceleration model can be used to accurately project the reliability of the LED arrays under normal operating conditions. The methodology was to apply statistical analysis to LM-80 test data and obtain accelerated models for life-stress relationships and life-time distributions. The Arrhenius-Weibull, Generalised Eyring-Weibull and Inverse Power-Weibull models were obtained and were compared for their effectiveness in to predicting the reliability of LED arrays.