An IGZO TFT based in-cell capacitance touch sensor

An in-cell active matrix capacitive touch sensor using IGZO TFT is proposed in this paper. The sensor does not need touch deformation, complicated detection mechanisms or extra components. In the sensor, touching events are identified as capacitive coupling between internal detection electrodes and touch objects. Then the coupling can be converted to voltage signal and amplified. TFT sizes are decreased for the high mobility and good uniformity of IGZO, which result in a significantly improved accuracy. A capacitance with the order of 1 fF caused by the coupling could be detected and converted to an adequate output voltage signal.