1D and 2D analog 1.5kHz air-stable organic capacitive touch sensors on plastic foil

In this work we present both a 1D and a 2D 4x4 capacitive touch sensor built in a dual-gate organic thin-film transistor technology on flexible foil. The maximal sample rate of the sensor read-out is 1.5kS/s, which results in a refresh rate of 93Hz for the 2D touch pad. With the given performance it is technically feasible to increase the sensor area by 4X to ~50cm² with the same accuracy reaching a refresh rate of 23Hz. The analog sensor output can further be interpolated and an example is given that proves at least a single bit of improvement per dimension. The output of the touch sensors is given by a ratio of capacitances and consequently the sensor is insensitive to variations and is air-stable. The 1D and 2D sensors measure 1.0x4.4cm² and 3.5x3.5cm² respectively. The sensor chip micrographs are presented in the figure.