Research On The Reliability Of LED Lamps Affecting Factors And Evaluation Method

For the enormous potential of long lifetime and energy efficiency, LED is predicted to bethe mainstream lighting sources of the21st century. Lifetime is representative in all parameterfor the reliability of LED lamps. Both LED manufacturers and users, the lifetime of LED isone of the most concern problems in the industry. So it has great practical significa nce toresearch the lifetime of LED. And now, the research on the lifetime of LED is still stay on thelight source. However, people pay more attention on the lifetime of LED lamps for using. But,it is different than LED light source, the affecting factors on the lifetime of LED lamps arenumerous and complicated. At the same time, the degree to each factors affects the lifetime ofLED lamps varies. So, there isn’t a reasonable and effective method to predict its lifetime inthe word. Fuzzy comprehensive evaluation method could make overall evaluation for somethings or phenomenon which affected by various factors, and it could well solve the vagueand hard to quantify problem. The method is widely used evaluating the reliability of railway,bridge and other complex system affected by various factors. So it is significance forpredicting the lifetime of LED lamps in the method.In this thesis, LED light source and LED lamps will be researched, the specific work andachievements are as follows:The existing method that evaluate the lifetime of LED uses flux maintenance rate asparameter. However, color parameter drift is an important indicator to evaluate the lifetime ofLED. So it is need establish a new method to evaluate the lifetime of LED use colorparameter as indicator. Research on the lifetime of several LED light source by currentaccelerated life tests and temperature accelerated life tests. It is obtained the samples practicallifetime respectively are67136h and14572h.It is comprehensive analyzed the affecting factors on the lifetime of LED lamps in LEDcomponent, power driver, heat dissipates system, and the working conditions. At the sametime, divided the second level factors aims at the first level factors. Based on the differentdegree of each affecting factor, it evaluated through investigating20experts in the field of LED lighting, so make the evaluation results more accurate and convincing. Based on theweight of each affecting factors on the lifetime of LED lamps, it is proposed the predictmodel on the lifetime of LED lamps by the fuzzy comprehensive evaluation method. Themethod is effective to evaluate the complex systems. It is simulated calculated of two LEDlamps by this method, and the calculation results are obviously different to change oneaffecting factor merely. It is also proved that it is certain credibility to predict the lifetime ofLED lamps by this method. But it need experimental test to promote the method.