Feasibility Study on Multi-Touch Ultrasound Large-Panel Touchscreen Using Guided Lamb Waves

Abstract

In this paper, we propose a transmission method, analysis, and implementation of an ultrasound touchscreen system based on Lamb waves. The basic principle of this system is to use the signals reflected from the fingertip contact. The inverted phase transmission method, which alternately transmits two opposite phases of input signals, was proposed to improve the signal contrast of the reflected signal from the fingertip. Experimental validation of this system was demonstrated on a 40-inch glass plate (800 mm x 600 mm) containing eight pairs of sensors. For imaging and localization, a simple and common method is used: the delay and sum method for imaging and the center of mass for localization. Compared with existing ultrasound technology, the proposed system is implemented in a large panel without using the training or prepared database. The system also provides reliable contact detection, simplicity, and other advantages of the present acoustic techniques.