Patent ID: 8890804
Filing Date: 2014-11-18
Classification: G01V,G06F

Abstract:
1. A coordinate sensor, comprising: a light-emitting element; at least two line sensors in which a plurality of light-receiving elements are arranged in X direction and Y direction, respectively; and a light-shielding body that prevents light other than light emitted from said light-emitting element from entering said light-receiving elements, a light reception signal detection circuit that converts the light detection amount at each of said light-receiving elements into an electrical signal; a memory that stores electrical signals respectively corresponding to light detection amounts at said light-receiving elements with no detection object present when said light-emitting element was ON and when it was OFF when the coordinate sensor was in an initial condition; and a coordinate detection circuit that determines the location of the detection object based on electrical signals from said light reception signal detection circuit and said memory, wherein said coordinate detection circuit determines coordinates pointed by a detection object in accordance with changes in light detection amounts at said light-receiving elements, wherein said coordinate detection circuit determines that the detection object is present on coordinates corresponding to a light-receiving element when an electrical signal value corresponding to the light detection amount at said light-receiving element when said light-emitting element is ON is smaller than a sum of: wherein said coordinate detection circuit causes the amount of light emitted from said light-emitting element to change from that in the initial condition so as to increase, among the light-receiving elements receiving light from said light-emitting element without being blocked by a detection object, the number of the light-receiving elements in which a difference between (i) the light detection amount when said light-emitting element is ON and (ii) the light detection amount when said light-emitting element is OFF is unchanged since the initial condition.