Failure Analysis And Reliability Optimization Of LED Lighting Appliances

With the rapid development of LED lighting technology,China’s LED lighting market scale is also enlarging.However,many problems still lie in the domestic LED lighting industry.To begin with,this thesis will analyze the problems existing in the development of LED industry from the perspectives of national policy,industry standard,enterprise technical level,industrial layout and so on.because the lighting electrical appliance industry belongs to the high-tech,high added value,high investment industry,so the technical content of its products is relatively high,which need to have a strong research and development ability.Therefore,it is an important means to improve the service life,safety and reliability of LED lamps to study the failure mechanism and failure mode of the whole and each key subsystem.This thesis intends to take LED lamps as the research object and uses the means of life acceleration experiment combined with finite element simulation to conduct in-depth research on the failure mechanism of LED lamps under high stress conditions.Combined with practical applications,the life prediction model of LED lamps under high stress conditions is established.It is of great scientific significance and economic value to provide theoretical basis and technical support for reliability evaluation of LED lamps under high stress conditions.Based on the above reasons,the main work of this thesis is as follows:1)This thesis studied the failure mode and failure mechanism of test samples under high stress state based on reliability analysis method,which start from the luminescence principle and internal structure of LED lighting appliances,combining with the structure and performance characteristics of test samples,and the test samples were divided into three sub-systems,so as to better judge the weak links of test samples.Then the reliability of the test sample is evaluated comprehensively.2)On the basis of failure mode analysis,this thesis carried out reliability test of LED lamps,determined the stress level required for accelerated test,designed reasonable and reliable test methods,completed the constant temperature aging test of LED lamps and accelerated life test of LED lamps,analyzed the test results combined with the test data and found out the main environmental factors affecting the reliability of LED lamps.The finite element method was used to conduct thermal and modal analysis on the drive circuit board system of LED packaging and LED lamps.According to the simulation results,the causes and positions of failures of LED lamps and lamps were found,and the weaknesses of LED packaging and PCBA were revealed: chip and electrolyte capacitance.3)On the basis of obtaining a large amount of test data,the Arrhenius model combined with the least square method and significance analysis method was adopted to realize the life prediction of LED lighting system and establish the life model of LED lighting system.By using FMECA reliability analysis method,the main failure forms of LED lighting appliances are obtained: chip material defects lead to light decay and silicone performance degradation.According to the defects of LED lighting appliances,it is improved to make its quality and reliability perfect.