| 摘要 |
PROBLEM TO BE SOLVED: To provide a coordinate input device, a coordinate input system, and a coordinate input method, capable of preventing reduction in detection accuracy in a region with difficulty in position detection by detecting a contact position of an object to be detected using a triangulation method.SOLUTION: A coordinate input device 3A is provided with at least three light receiving means including imaging units 20 and 30 which are arranged at both ends of a side of a light guide plate 20 and an imaging unit 50 which is arranged at least at one end of another side. A detection part 4 is provided with an angle determination part 5 which determines whether the viewing angle of a contact position P is equal to or less than a threshold angle δ on the basis of the outputs from the imaging units 20 and 30 based on a contact position P of a touch pen 40 on the surface of the light guide plate 20, and an alternative output calculation part 6 which obtains the coordinate of the contact point P on the basis of either one of the outputs from the imaging units 20 and 30 and the output from the imaging unit 50 when the viewing angle is determined to be equal to or less than the threshold angle δ. |
