Three-Transistor AMOLED Pixel Circuit With Threshold Voltage Compensation Function Using Dual-Gate IGZO TFT

In addition to the gate electrode at the bottom, a dual-gate amorphous InGaZnO4 thin-film transistor (TFT) has a secondary gate electrode on the top. The threshold voltage (Vth) of the TFT using the bottom gate in its normal operation can be controlled by the top gate. Based on this phenomenon, a simple circuit of active-matrix organic light-emitting diode using the top gate to compensate threshold voltage variation is proposed. This new pixel circuit uses only three TFTs and two capacitors. The validity of Vth compensation is verified experimentally.