Research On Heat Dissipation Of The High Power COB LED

Light emitting diode(LED)is made of compound semiconductor light emitting components,through electron-hole combined to convert electrical energy into light.With the LED power rating is growing,the LED junction temperature will become larger,this will lead to LED device life shortening and light extraction efficiency becomes low,so the research on heat dissipation of the LED is necessary.The encapsulation function is to provide sufficient protection for the chip to prevent long-term exposure or mechanical damage to the chip in the air or even failure.This paper introduces the basic thermal design theory of high power LED chip,the heat dissipation model of the high power COB LED is established by COMSOL software based on this theory,and its heat dissipation is studied and optimized.First of all,the influence of the insulating layer on the thermal performance of the high power COB LED is studied by the heat dissipation model of the high power COB LED in this paper.The results show that when the thermal conductivity of the insulating layer increases from 0.5W/(m·K)to 2.5W/(m·K),the junction temperature of the high power LED decreases obviously,the thermal conductivity of insulating layer plays a decisive role in the junction temperature of the high power LED.However,its thermal conductivity exceeds 6.5W/(m·K),the influence of the insulating layer can be ignored.Then,the influence of the thickness of the insulating layer on the junction temperature under different thermal conductivity was studied.The results show that the high power LED junction temperature can be effectively reduced by reducing the thickness of insulation layer when the thermal conductivity of insulating layer is less than 2.5W/(m·K).Finally,the high power LED chip is optimized according to the insulating layer.The first option: microporous insulating layer optimization;the second program: the high power LED chip package in the electrical insulating radiator directly.Simulation shows that the two schemes have a good optimization effect,the high power LED junction temperature decreased respectively by 28.3? and 13? when the power rating is 11 W.Secondly,the influence of radiator on the junction temperature of the high power multi-chip COB LED is studied in this paper.The results show that the maximum junction temperature of the high power LED decreases with the increase of air heat transfer coefficient,and the air heat transfer coefficient is between 5W/(m~2K)and 15W/(m~2K)for 3×3 chip high power COB LED module maximum junction temperature reduction significantly.Then,the effect of chip distance on chip junction temperature was studied.The results show that when the chip spacing is 4.0mm,the maximum junction temperature range of the 3×3 chip high power COB LED is very small,the thermal coupling phenomenon is very weak.Finally,simulation of temperature field distribution of the high power LED module in 2×8,4×4 two layouts.The results show that the maximum junction temperature of the 2×8 layout is lower,the temperature difference is smaller,and the 2×8 chip high power COB LED module has better heat dissipation than the 4×4 chip high power COB LED module.