New External Compensated Circuit to Achieve Uniform OLED Luminance for High-Resolution AMOLED Displays

Abstract

This work proposes a simple-structure pixel circuit composed of low-temperature polycrystalline-silicon thin-film transistors (LTPS-TFTs) and external threshold voltage (VTH) compensation circuit shared by whole row for active-matrix organic light-emitting diode (AMOLED) displays. This proposed circuit combines parallel addressing scheme and voltage-programming method to increase compensation time for accurately detecting threshold voltage variations of driving TFT, and the voltage drop (I-R drop) in power line. Simulation results show that the relative emission current error rates are below 2.93 % and 2.62 % when variations of VTH are ± 0.5 V and VDD I-R drop is ±0.5 V, respectively, verifying that the novel pixel design has great potential for use in high resolution AMOLED displays.