Patent ID: 6091405
Filing Date: 2000-07-18
Classification: G06F

Abstract:
An input device for a visual display screen, the device comprising a first assembly including:a source of diverging light comprising rays directed substantially parallel to the surface of the screen, said rays substantially covering the screena shutter disposed to interrupt a portion of said light before it reaches the screen, said shutter comprising an array of shutter elements, each element having a unique address, further wherein each element has a transparent state in which light from said light source is transmitted and an opaque state in which light from said light source is blocked;shutter drive circuit means coupled to said shutter elements for controlling the state of each of said shutter elements so as to provide a scanning light beam as an output of said shutter; anda photodetector for detecting interruption of said light beam by an article positioned in the plane and for providing a first output signal upon detecting said interruption of said light beam.