Implementation of ultrasonic touchless interactive panel using the polymer-based CMUT array

An innovative touchless interactive panel based on the ultrasound echo-location principle is proposed. The fabrication process of the polymer-based capacitive micro-arrayed ultrasonic transducer (P-CMUT) array is described. A method is then proposed for determining the position of the user´s finger relative to the screen based upon the time of arrival (TOA) of the acoustic echo signals reflected from the fingertip and the geometrical relationship between the transmitter and the receivers. Various signal processing techniques and supporting algorithms are proposed for obtaining reliable and precise fingertip position estimation. The feasibility of the interactive panel is verified by constructing a prototype model and performing a series of representative pointing operations using a commercial computer application.