Gallium nitride-based blue light LED junction temperature and temperature distribution testing method

The invention discloses a gallium nitride-based blue light LED junction temperature and temperature distribution test method. The method comprises the following steps: firstly, collecting LED self-luminous pictures at different temperatures under excitation current; providing rated working current while applying excitation current, disconnecting the working current after the junction temperature is kept stable, and continuously collecting pictures to obtain self-luminous pictures before and after switching; selecting a certain position of the device on the self-luminous pictures at different temperatures, and fitting to obtain a change relation of a pixel value along with the temperature; selecting the first self-luminous picture after current switching, obtaining a pixel value of the same position, and obtaining junction temperature according to a change relation of the pixel value along with temperature; and finally, selecting different positions to obtain temperature distribution of the device. A switching