Research On The Technology Of Rapid Sorting Of High Power LED Reliability

High-power LED is a new semiconductor light source which has attracted much research attention because of its incomparable performance such as high Lumen efficiency, long-life and less power-consumption. Recently, with high-power LED entering the market, the development of high-power LED is fast, so higher reliability of high-power LED is required.This thesis focuses on the relationship between heat-sensitive parameters and the reliability of high-power LEDs and the relationship between ideal factors of high-power LEDs and their lifetime. A method in which heat-sensitive parameters and the ideal factor can be used to appraise the quality and reliability of high-power LEDs fast and without scathe is presented. The main contribution and results are as follows:1,Lighting mechanism of LEDs, the potential markets for LEDs and the published research on the reliability test of high-power LEDs.2,Detailed description of high-power LEDs photoelectric parameters and their calculation methods are given.3,In view of the increasing of High-power LED PN junction temperature, High-power LED's optical, electrical and thermal properties will change. Then the relationship between junction temperature and thermal resistance of high-power LEDs is analyzed. At the same time heat-sensitive parameters could show the relationship between junction temperature,thermal resistance and the reliability of high-power LEDs.4,The electric current accelerated aging experiments are carried out. The ideal factors of high-power LEDs and their lifetime are got by using the least square method. And the relationship between ideal factors of high power LEDs and their lifetime could be got.5,The digital circuit design based on microcontroller AT89c51, and the analog circuit design including numerical control constant current source,constant voltage source and measurement circuit are designed.6,The working flow of the measurement and control unit and the main program of this part are introduced. The setting of the serial communication port and the serial communication protocol between the microcontroller and the host computer is designed. At last the host application software is designed by Visual C++ programminglanguage.7,Conclusions and future research work are given.