Improvement of flicker phenomenon at low frequencies in AMOLED displays by applying compensation scheme of variable reset voltage

In this study, we propose a novel compensation scheme that utilizes variable reset voltage (VRV) to mitigate the flicker phenomenon observed in low temperature poly-Si and oxide (LTPO) active-matrix organic light emitting diode (AMOLED) displays at low frequencies. We have experimentally demonstrated that the flicker caused by luminance fluctuations at low frequencies is the result of interactions between the slow transient de-trapping of the oxide thin film transistor (TFT) and hysteresis of the driving TFT (D-TFT). Although slow transient de-trapping of the oxide TFT is difficult to be compensated, we have demonstrated that D-TFT hysteresis can be modulated by adjusting the gate in panel (GIP) timing and reset voltage. Accordingly, the luminance amplitude component at 1 Hz was significantly reduced from 0.201 cd/m² to 0.093 cd/m² by applying sequentially modulated VRV within the skip frame where image data were not updated. Consequently, the flicker phenomenon was improved at low driving frequencies below 10 Hz.