4-Dimensional Sensing in Interactive Displays Enabled by Both Capacitive and Piezoelectric Based Touch Panel

Abstract

Interactive displays have been intensively used in consumer electronics, e.g., smartphones, for providing highly efficient human-machine interactions, assisting users to process a vast amount of data. However, current mainstream interactive displays only support 2-dimensional detection, strongly limiting user experience. In this paper, we present a piezoelectric and capacitive based technique for obtaining 4-dimensional detection, including (x-y axis) location, force, and hovers sensing in interactive displays. Here, electrodes are located on and underneath the piezoelectric layer, constructing a sandwich structured device. A self-capacitance-based technique is employed for location and hover sensing. Force-induced charges are collected and interpreted as force amplitude. As capacitive and piezoelectric sensing techniques occupy different frequency bands, these two signals can be smoothly separated, and 4-dimensional touch sensing is achieved concurrently, with the recognition of static force and hovers touch events.