Piezoelectric vs. Capacitive Based Force Sensing in Capacitive Touch Panels

High sensitivity force sensing is a desirable function of capacitance touch screen panels. In this paper, we report on a dynamic force detection technique by utilizing piezoelectric materials. The force-voltage responsivities are investigated for four widely used stack-ups, with various panel thicknesses and touch locations. Based on the theoretical analysis and simulation results, the maximum responsivity and the signal-to-noise ratio are achieved at 0.42 V/N and 59.1 dB, respectively. The proposed technique implements force sensing successfully, enhancing the human-machine interactivity experience.