Measurements of LEDs Spectral Characteristics and Junction Temperature

The junction temperature and spectral charateristics of AlGaInP based on red,yellow and InGaN based on green,blue and white light-emmiting diodes(LEDs) were measured by using the temperature coefficients of the diode forwared voltage and thermal resistance methode.A linear relation between junction temperature and emission peak wavelength was found for AlGaInP based on red and yellow on LEDs.For the InGaN+YAG white LED,the junction temperature is inversely proportional with the ratio of the total radiation power(W) to the blue radiation power(B) W/B.The experiment results reveal that spectral characteristics measurement method is a good approach for determining junction temperatures of AlGaInP based and phosphor-converted LEDs.