38‐3: A Study on the Improvement of Low Gray Mura

This study investigates the factors affecting the low gray mura in OLED displays. It was determined that the most significant factor influencing low gray mura is the current distribution in the low gray region of the driving Thin‐Film Transistor (TFT) within the compensation circuit. Additionally, the impact of the OLED material’s capacitance on mura was explored using Monte Carlo simulations. Among the OLED materials tested, the aperture ratio of the green pixel demonstrated a high sensitivity to variations in subthreshold slope (SS). Monte Carlo simulations, which incorporated the low‐current distribution of the Driving TFT (DTFT), were performed to assess these effects. The simulations revealed that when the green aperture ratio decreased to 70%, the mura level, evaluated at 2 nit and 32 gray, decreased by approximately 10%. This finding suggests that adjusting the aperture ratio alone, without requiring process modifications or material changes, can significantly reduce mura.