Apparatus and method to improve resolution of infrared touch systems

摘要

A touch system using a plurality of infrared ("IR") transmitters and receivers, and a method of determining with increased resolution the location of a touch between the IR transmitters and receivers using on-axis and off-axis detection are disclosed. The inventive touch system and method use, in conjunction with the on-axis and off-axis detection, a coarse and fine sweep of the transmitters and receivers to increase the resolution of identified touch location. The method of determining a touch location involves selection and activation of particular off-axis infrared transmitter and receiver pairs determined from a triangulation interdependence between the x and y coordinates. The increased resolution of the identified touch location is achievable using the inventive system and method without the need for an increased number of IR transmitters and receivers and without the need for higher speed processing capability.