功率型LED热特性测试及评价

Thermal Performance Testing and Evaluation of High Power LEDs

针对现有热特性测试及评价标准尚不完善的问题,以功率型发光二极管(LED)的精确热特性测试及评价为目标,采用光热一体化测试技术对不同的LED灯珠进行了热特性测试,研究了测试电流对K值标定及结温测试的影响,分析了热特性随环境温度的变化情况,提出了热性能测试及评价的合理建议。研究结果表明:测试电流对K值标定及结温测试有较大影响,测试电流的合理选取与芯片本身及功率的大小有关;材料的热导率随环境温度变化波动,对于某些高温使用环境,仅25℃的热性能参数数据并不能准确反应LED的热特性;热阻测试的准确性与光功率有关,光热一体化测试有利于得到准确的热特性数据。

The existing criteria of thermal performance testing and evaluation is still not perfect.Aiming at testing and evaluating the thermal performance of high power LEDs accurately, the thermalperformance was test for different LEDs using integrated photothermal techniques. The impact of testingcurrent on the temperature-voltage coefficient ＂ K＂ and junction temperature measurement wasresearched, and the thermal performance with the changes of environment temperature was discussed.The reasonable suggestions for thermal performance testing and evaluation were presented. The resultsshow that the testing current has a significant impact on the ＂K＂ and junction temperature measurement,and the reasonable selection of testing current lies on the chip and the power of LEDs. The conductivity ofmaterials can be changed due to the ambience variation of circumstance temperature. The thermal parameterdata in 25℃ can not accurately reflect the thermal performance of LEDs for some high temperature occasions.The accuracy of thermal resistance measurement is related to optical power, the integrated photothermal testingis helpful to obtain accurate thermal data.