This paper proposes amorphous indium- gallium-zinc oxide thin-film transistors (TFTs) fourtransistor- two-capacitor (4T2C) pixel circuit in combination with a top-anode organic light-emitting diode (OLED) for the use in 8K4K active-matrix organic light-emitting diode displays (AM-OLEDs). The proposed pixel circuit compensates for driving TFTs threshold voltage (VTH) shifts and mobility variations, VDD current-resistance (I -R) drops, and VSS I -R-induced rises. Both the positive and negative VTH of the driving TFT can be sensed by the proposed circuit. In this paper, we analyze the impact of the driving TFT compensation time for low gray levels. The current error rates are calculated when TFT mobility variations are considered. The proposed pixel circuit allows an increase in the compensation time to reduce the impact of driving TFT VTH and mobility variations on the performance of 4T2C pixel circuit. Conventional twotransistor- one-capacitor, five-transistor-two-capacitor, and proposed 4T2C pixel circuits are simulated and compared in this paper. The proposed pixel 4T2C circuit reduces the current error rates to below 5.79% when the VTH shifts of ±2 V, mobility variations of ±10%, VDD I -R drops of 1 V, and VSS I -R rises of 1 V are all considered. We show that the proposed 4T2C pixel circuit is suitable for 8K4K AM-OLEDs.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering