PROJECT TITLE :

Optimal Design of Life Testing for High-Brightness White LEDs Using the Six Sigma DMAIC Approach

ABSTRACT:

Life testing is an essential reliability assessment procedure to qualify a replacement product or technology before being released to the market. High-brightness white light-weight-emitting diodes (HBWLEDs) with high potency, environmental benefits, and high reliability have attracted increasing interest in the field of lighting systems. However, because of the long lifetime of LEDs, traditional life testing ways for LEDs, that record only failure time, are time consuming and expensive. Thus, planning an optimal life testing process for HBWLEDs is desirable for accelerating LED technology innovation and development. This paper applies the Six Sigma define–live–analyze–improve-control (DMAIC) approach to analyze the restrictions within the traditional life testing for HBWLEDs and optimize the life testing procedure. The goal is to shorten the testing time, reduce the testing operation cost, and maintain accurate reliability estimation. In this work, a general reliability estimation methodology with degradation knowledge is developed by integrating a recursive unscented Kalman filter approach to estimate HBWLED reliability. The results show that, with the help of a recursive UKF, the accuracy of reliability estimation will be improved compared with the normal nonlinear least squares approach. Furthermore, the operation time and cost of LED life testing will be reduced by 57.75% and 71.51%, respectively, compared with traditional life testing.