4-Dimensional sensing in interactive displays enabled by both capacitive and piezoelectric based touch panel

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.