Process Variation of Pixel Definition and Effects of Flexible OLED Luminance Degradation

We focus on the effects of process variation of the pixel definition layer (PDL) on luminance degradation following a 2-parameter stretched exponential decay (SED) model. It is found that when the shape parameter $(\boldsymbol{\beta}) > 1.1$ in the blue pixel, the predicted lifetime can meet the target reliability. It is also exhibited that the scale parameter ($\boldsymbol{\tau}$) is somewhat sensitive to the process variation of an active area size. As long as the process variation varies within $3\boldsymbol{\sigma}$, the reliability exists within the target. Using the model of 2-parameters ($\beta, \tau$) and acceleration factor (n) extracted from the long-term luminance acceleration test, an expected lifetime in the process variation can be accurately predicted. Detailed design rule for the active area of the PDL will be further discussed from reliability perspectives.