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设计了一种采用双光谱参数表征GaN基蓝色LED结温的新方法。采用光谱仪(OSA)测量不同环境温度、不同脉冲电流驱动下,GaN基蓝色LED的光谱分布,先忽略脉冲电流的热效应,构建驱动电流、质心波长、半高全宽(FWHM)和结温四者之间的关系;然后利用该关系,结合实际点灯条件下LED的光谱分布,计算出对应的LED结温和驱动电流。再根据统计得到的GaN基蓝色LED脉冲电流-结温修正系数,对所得结温进行修正,得到考虑脉冲电流热效应后更准确的LED结温。研究表明,不同类型的LED脉冲电流-结温修正系数差别较小,当脉宽为2ms时,1 W GaN基蓝色LED的脉冲电流-结温修正系数为-5℃/A。与正向电压法相比,采用双光谱参数法得到的结温平均误差约为2℃。因此,双光谱参数法可以较准确地测量GaN基蓝色LED的结温。
A new method to characterize the GaN-based blue LED junction temperature using dual spectral parameters was designed. Using OSA to measure the spectral distribution of GaN-based blue LEDs under different ambient temperatures and different pulse currents, the thermal effects of pulse current were first ignored and the driving current, centroid wavelength, full width at half maximum (FWHM) and junction temperature And then use the relationship, combined with the actual lighting conditions under the LED spectral distribution, calculate the corresponding LED junction temperature and drive current. Then based on the calculated GaN-based blue LED pulse current - junction temperature correction factor, the resulting junction temperature is modified to give more accurate LED junction temperature considering the pulse current thermal effect. The results show that there is little difference between different types of LED pulse current - junction temperature correction coefficient. When the pulse width is 2ms, the pulse current-junction temperature correction coefficient of 1 W GaN-based blue LED is -5 ℃ / A. Compared with the forward voltage method, the average error of the junction temperature obtained by the dual-spectral parameter method is about 2 ℃. Therefore, the dual spectral parameter method can more accurately measure the junction temperature of the GaN-based blue LED.