Touch Sensor Array With Integrated Drivers and Comparator Using a-IGZO TFTs

Abstract

Integration of an amorphous indium-gallium-zinc-oxide thin-film transistor (TFT)-based self-capacitive touch sensor array with its peripheral drivers and readout circuits is reported. Each pixel consists of one touch electrode and five TFTs that enable a pixel-by-pixel driving scheme via integrated row and column drivers made of shift registers. Outputs from all sensor pixels are fed into an integrated comparator and compared with a reference voltage to generate a more readable low or high output level. A ~7 V difference between the touch and untouched states could be detected, making the proposed touch sensor a promising candidate for flexible electronics.