A system for providing input to a computer comprises a touchscreen apparatus for generating a grid of horizontal and vertical light beams and producing a set of output signals, each indicating whether a corresponding one of the light beams strikes an object. A scanning device repeatedly scans the states...http://www.google.de/patents/US5025411?utm_source=gb-gplus-sharePatent US5025411 - Method which provides debounced inputs from a touch screen panel by waiting until each x and y coordinates stop altering
