New a-IGZO Pixel Circuit Composed of Three Transistors and One Capacitor for Use in High-Speed-Scan AMOLED Displays

An amorphous indium-gallium-zinc-oxide (a-IGZO) pixel circuit with three transistors and one capacitor is proposed for use in high-speed-scan active-matrix organic light-emitting diode (AMOLED) displays. The proposed pixel circuit can compensate for the threshold voltage shifts in both normally-off and normally-on a-IGZO TFTs. Based on the simulation results with ±1 V threshold voltage shifts of the driving TFT, the relative error rates of OLED currents are less than 4.46% for the entire range of data voltages (-9.9 V ~ 5 V).