Recoverable Residual Image Induced by Hysteresis of Thin Film Transistors in Active Matrix Organic Light Emitting Diode Displays

A recoverable residual image is observed and analyzed in voltage driven active matrix organic light emitting diode (AMOLED) displays of which pixel circuits consist of two thin film transistors (TFTs) and one capacitor. The cause of the residual image is proven to be the hysteresis of the driving TFT in the pixel. The hysteresis of the p-channel TFT can be explained by hole trapping and de-trapping at the interface region of the channel. The recovery time of the residual image also strongly depends on the hysteresis level. We have found that the residual image can be eliminated by reducing the hysteresis level of TFTs.