One Gate Diode-Connected Dual-Gate a-IGZO TFT Driven Pixel Circuit for Active Matrix Organic Light-Emitting Diode Displays

Abstract

A dual-gate (DG) amorphous indium-gallium- zinc-oxide thin-film transistor (TFT)-driven pixel circuit for active-matrix organic light-emitting diode displays is presented. One gate of the DGs serves as a primary gate (PG) and the other as an auxiliary gate (AG). The threshold voltage (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</sub> ) of the DG TFT under the PG operation is modulated by the AG bias voltage. The VTH variation (ΔV <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</sub> ) is compensated with the AG and the drain diode-connected structure. The validity of the presented pixel circuit is experimentally verified. The measured current error rates are less than 3.2% at a ΔV <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</sub> of TFT = ±0.5 V and a ΔV <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">TH</sub> of OLED = 0.5 V with the emission current ranging from 7 nA to 1.13 μA.