On-line measurement and analysis of high-power LED characters in accelerated life test

Accelerated life test is most frequent used method in electronics and optoelectronics device reliability, failure model and life prediction research. Due to lack of suitable equipment and instruments, for now, the LED properties are measured by off-line methods during the accelerated life test which require the experiment process have to be interrupted. In our work, we built a system which could carry out on-line measurement of LED properties (such as luminous flux, color temperature, junction temperature and thermal resistance) during the accelerated life test. As we all known, the structures of different LED chips (horizontal, vertical and flip) have great influence to their illuminant and thermal performance. In this study we compared the advantage and disadvantage of their performance.