| 摘要 |
<p>PROBLEM TO BE SOLVED: To securely prevent a dip from becoming undetectable due to the influence of environmental light and to prevent erroneous detection owing to the environmental light. SOLUTION: A coordinate input device is provided with an input control means for switching on a light source 201, inputting light quantity data which the individual light receiving devices of CCD 204 receive as data during lighting, switching out the light source 201 and inputting light quantity data which the individual light receiving devices of CCD 204 receive as data in a light extinguished state and a setting means for setting correction threshold data for the respective light receiving devices on the basis of light extinguished time data of the respective light receiving devices. The threshold is corrected for each light receiving device by using correction threshold data. Lighting state data for each light receiving device is compared with the threshold after correction for each light receiving devices to detect the coordinate on a touch panel.</p> |
