Optical measurements of OLED panels for lighting applications

Optical characteristics of organic light-emitting diode (OLED) panels have been investigated for the purpose of developing a test method for OLED panels for lighting applications. The electrical characteristics, total luminous flux and chromaticity (x, y), and their dependence on supply current, stabilization time, ambient temperature, and operating position, were measured and evaluated. Directional characteristics of these panels, including angular luminous intensity and chromaticity distributions as well as spatial non-uniformity of luminance and temperature, were also measured and evaluated. From the data obtained, critical optical characteristics to be measured for OLED panels and suitable measurement methods and conditions for testing OLED panels are discussed.