Real-time Monitoring System For LED Luminous Degradation In Thermal Aging

LED Lighting is an industry with huge market potential caused by its incomparable advantages to traditional lighting but somehow its development is restricted by a series of issues such as poor reliability,lack of standards,underdeveloped testing method and high price.Therefore,how to improve testing method to accelerate the improvement of LED quality and performance is a study subject of importance.Traditional testing methods require at least 6000 testing hours according to Energy Star of DOE(US)and TM-21,a technical memorandum being published by IESNA.The time consumption of testing slows down LED development process in an obvious and inevitable way,hence drags the LED product evolution to the market.To address this issue,the study subject of this paper is to develop a real time monitoring system for LED luminous degradation to record the real-time changing of performance data in a thermal aging test,which can be applied to rapid lifespan estimation.The focus of the this study subject is to develop a real time monitoring system for LED luminous degradation by introducing and analyzing the theories of LED luminous degradation models,exponential attenuation method and Arrhenius equation,exploring the feasibility of using lux maintenance to replace lumen maintenance in life prediction and finally designing an equipment to realize real-time morning purpose.This equipment is environmental testing chamber based with a group of high precision optical,electrical and thermal sensors/data collectors being set right outside the chamber window.To collect the optical,electrical and thermal parameters of each testing sample,a sample controller is being developed to realize lighting up every LED samples one by one,while illuminance value is being collected by optical sensor,electrical value is recorded by power supply and thermal value is collected by thermocouple module.A software is being developed to collect and store all the testing data in a computer which can be used for data analysis and lifespan estimation.