基于相对光谱强度的非接触式LED结温测量法

基于一体化封装高导热铝板，利用蓝光芯片及常用YAG荧光粉，制备了大功率白光LED，并研究了其在不同结温下的光谱变化规律。发现白光LED辐射光谱在波长485 nm处辐射强度具有极小值，并且此波长的辐射强度与LED结温存在良好的线性关系，以此为依据给出了该波长辐射强度与结温的关系公式，测量了LED结温，并与正向压降法及光谱法的测量结果进行对比。实验结果显示：所提出的结温测量方法与正向压降法测量结果差距不超过2 ℃，该方法保持了正向压降法的结温测量较为准确的优点，克服了光谱法的光谱漂移过小，对测试结果带来较大误差的缺点，同样也具有光谱法的实用性强、高效直观、非接触测量、不破坏灯具结构的优点。

A New Non-Contact Method Based on Relative Spectral Intensity for Determining Junction Temperature of LED

The high-power white LED was prepared based on the high thermal conductivity aluminum, blue chips and YAG phosphor. By studying the spectral of different junction temperature, we found that the radiation spectrum of white LED has a minimum at 485 nm. The radiation intensity at this wavelength and the junction temperature show a good linear relationship. The LED junction temperature was measured based on the formula of relative spectral intensity and junction temperature. The result measured by radiation intensity method was compared with the forward voltage method and spectral method. The experiment results reveal that the junction temperature measured by this method was no more than 2 ℃ compared with the forward voltage method. It maintains the accuracy of the forward voltage method and overcomes the small spectral shift of spectral method, which brings the shortcoming on the results. It also had the advantages of practical, efficient and intuitive, noncontact measurement, and non-destruction to the lamp structure.