Touch panel having parallax compensation and intermediate coordinate determination

摘要

Disclosed is here a coordinate input apparatus in which light sources and light receiving elements opposing thereto with an input operation space therebetween are arranged in an X-axis direction and in an Y-axis direction. The light sources and said light receiving elements form a plurality of pairs and the light sources are sequentially driven to accomplish a scan operation. Coordinates corresponding to the light receiving element of which a light path is interrupted by a coordinate input scan in the input operation space are outputtted as detection signals and as coordinate input data of a position where the light path is interrupted. The apparatus includes a double-precision coordinate calculate unit for calculating, when light paths of two adjacent light receiving elements are simultaneously interrupted, coordinates of an intermediate point associated with coordinates corresponding to the two light receiving elements and a coordiante value correcting unit for achieving a parallax correction on the coordinates calculated by the double-precision calculate unit by use of a correction table. As an output from the coordinate correcting unit is converted into be coordinates corresponding to the arrangement constituted with the light sources and the light receiving elements so as to be outputted as coordinate input data.