OLED luminance prediction using impedance measurements

Luminance is the main feature to follow an OLED degradation. Beside using photo-diodes, the luminance decay can be predicted with the help of the electrical characteristics of the OLED. Analysis of the impedance revealed a strong correlation between the luminance and the impedance time constant. As a result, the time constant is chosen as the main feature to track OLED degradation. The evolution of this latter is exponentially modelled through time at different stress levels using the design of experiments (DoE) methodology. Simultaneously, an exponential relation between the luminance and this time constant is selected, enabling the luminance degradation prediction through time. This method is an accurate novel solution for luminance tracking in particular and the OLED degradation in general with a total prediction error of 2%.