功率型白光LED可靠性的实验及仿真建模研究

快速推广LED产品到照明市场最主要的障碍在于长期的可靠性测试问题。由于长期的LED可靠性测试不符合快速且低成本的要求,因此本实验对白光LED进行步进式加速寿命老化测试,步进式环境温度从55oC到145oC变化。同时,对LED进行结温测试,并使用COMSOL仿真软件进行温度场分布仿真来模拟器件的发热情况,结果表明荧光胶处的温度高于LED芯片温度。在长期老化之后,对LED的光度进行测量,可以对LED的失效机理进行分析。通过研究温度对LED的光谱功率分布衰减的影响及光通量衰减的影响,发现在经过近3500 h的老化之后,LED的光衰很严重,表明电流及高温对LED的影响是极大的。

Experimental and Simulation Modeling Study on Reliability of Power White LEDs

A major hurdle for quickly promoting new LED products to the lighting market origi nated from the long-term reliability qualification tests,since conventional LED reliability tests did not meet the needs of a quick and cost-effective qualification.Therefore,step-stress accelerated aging tests of white LED were developed under an increasing accelerated aging temperature from 55℃to 145℃in this study.At the same time,the junction temperature of LED was tested and the tempera ture distribution was simulated by COMSOL simulation software to simulate the heating of the device.The results show that the temperature of phosphor gel is higher than that of LED chip.After a long pe riod of aging,by measuring the luminosity of the LED,the failure mechanism of the LED can be ana lyzed.The influence of temperature on the attenuation of spectral power distribution of LED and the attenuation of light flux are studied.It turns out that after nearly 3500 hours of aging,LED has a very serious light failure,indicating that the influence of current and high temperature on LED is significant.