Comparison of luminance distribution on the lighting surface of power LEDs

This work presents luminance distributions across the surface of mid- and high-power diodes. The changes in luminance on diode surfaces following changes in the observation angle were verified. Based on the conducted tests, non-uniform luminance distribution on LED surface for diverse observation angles (including the axial direction) was observed. Moreover, it was concluded that luminance changes are not in line with Lambert's law. As a result of research, it was also concluded that alterations of power-supply conditions do not exert any significant impact on the gradient of luminance changes on the surfaces of examined LEDs.