Patent ID: 6229601
Filing Date: 2001-05-08
Classification: G06F

Abstract:
A coordinate input apparatus which irradiates a predetermined position on a coordinate input screen with light from a designation unit to form a light spot, and detects the light spot by a coordinate detection unit to generate a coordinate output signal corresponding to the predetermined position on the coordinate input screen, comprising:light emitting control means, arranged in the designation unit, for flashing the light spot in a predetermined cycle;integration means arranged in the coordinate detection unit and constituted by a sensor array prepared by aligning in a line a plurality of photoelectric conversion sensors for detecting the light spot, and a ring-like charge transfer portion for separately integrating signals in light emission and non-light emission states output in synchronism with the predetermined cycle of the light spot from the sensor array;image sensing means arranged in the coordinate detection unit and having difference means for obtaining a difference signal from the signals in light emission and non-light emission states; andcoordinate arithmetic means for digitizing the difference signal between light emission and non-light emission states output from said image sensing means at a data width not less than n bits to perform coordinate calculation, thereby calculating a coordinate value having a resolving power substantially the nth power of 2 of the number of pixels of the sensor array.