研究和分析了用LED的发光强度来表征LED的相对辐射强度和结温之间存在的线性关系,据此设计并实现了类似于正向电压法,基于相对辐射强度的非接触式测试系统,使用NI USB6210数据采集卡在虚拟仪器平台上完成了图像采集、图像处理、线性拟合、界面设计的任务,得到相对辐射强度值与结温之间的关系,根据线性拟合关系式可得到被测器件的结温。本系统具有界面简洁、算法可靠和结果稳定的优点,使用该系统分别对单颗LED和LED阵列的实验数据进行拟合发现结温和相对辐射强度之间具有较好的线性关系,从而验证了非接触LED结温测试系统的可靠性。
The light emitting diode( LED) linear relationship,characterized by luminous intensity of LED,between relative radiation intensity and the junction temperature was studied and analyzed. A non-contact method test system based on the relative radiation intensity and similar to forward voltage law was designed to accomplish the objectives of image acquisition,image processing,linear fitting and interface design on virtual instrument by using NI data acquisition card USB6210,and the linear relationship between the relative radiation intensity and the junction temperature was obtained. According to the linear regression equation,the junction temperature can be obtained. The system owns simple interface,reliable algorithms and stable results. Respective measurements on single LED and LED array result good linear relationship between the relative radiation intensity and the junction temperature,which verifies the reliability of the non-contact method of the junction-temperature measurement of LED.