| 摘要 |
A coordinate input device which is capable of performing accurate and appropriate detection of a pen-up/pen-down state over the entire coordinate input surface, based on motion of an indication tool or the like in a direction substantially perpendicular to the coordinate input surface, and realizing a function equivalent to that of an indication tool equipped with a communication function without using the tool. A light-shaded position shaded from light on the coordinate input surface by input of the indication tool on the coordinate input surface is detected, and then the coordinates of the light-shaded position are calculated. Further, the pen-up/pen-down state of the indication tool is determined based on a temporal change in light shading in the light-shaded position.
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