Study On The Electrothermal Characteristics Of High-power LED And Its Influence On Light Decay Of Array Light Source

High-power LED have the advantages of high brightness,long life,energy saving and environmental protection,which make them occupy an important position in the field of lighting.In this thesis,the structure of general array light sources have been optimized based on point light source simulation,and an array structure light source that takes into account the uniformity of illuminance and temperature distribution has been determined.The light decay prediction of the array light source has been carried out to verify,and the effect of the electrothermal characteristics of high-power LED on the change of light decay of the array light source has also been studied in depth.It is of great engineering value for the production and application of high-power LED light source system in lighting market.Firstly,the electrothermal characteristics and the mechanism of light attenuation of high-power LEDs are analyzed^and the main stresses that cause the change of light decay of LED light source system under actual working conditions have been found in this thesis.Then the voltage and junction temperature model with temperature stress as the parameter have been designed,and the transfer function of forward voltage and junction temperature has also been obtained.The influence of the temperature dynamic change on the stability of the system has been analyzed.On the basis of point light source simulation,the illumination evaluation function of array structure has been designed,and the structure of experimental array light source has also been obtained combine with numerical optimization algorithm.To ensure that the illumination and temperature distribution were uniform at the same time,the array light source has been subjected to ray tracing and temperature finite element analysis The rationality of the design scheme of array light source has been verified.Secondly,the light decay model of array light source has been designed according to the insulation performance of electrified materials.And the temperature acceleration test has also been designed based on the model,including the determination of limit boundary curve,acceleration factor design,theoretical prediction curve of light attenuation under different junction temperatures,the time length of light attenuation with temperature acceleration replacement,and the design of junction temperature ladder and heat dissipation.The temperature distribution simulation and actual measurement of the array light source under each junction temperature condition have been compared,the junction temperature setting error has been reduced to ensure the invariance of the accelerated test temperature condition.Finally,the theoretical calculation of the light decay time has been performed by combining the theoretical prediction curve and the acceleration factor.The experimental samples of array light source have been assembled to carry out actual temperature acceleration test and routine work test,and the changes of light flux of the light source system under different junction temperature conditions have been measured and analyzed in real time.Under the condition of temperature acceleration,the light decay time has reached the design requirements,which efficiency has been proved.