| 摘要 |
<p>PURPOSE:To precisely correct finger touch input coordinate information by an unadjusted action by taking out an impressed voltage right after an on/off switch connecting the electrode of a coordinate input sheet and a power source and inputting said voltage as an impressed reference voltage to an A/D converter. CONSTITUTION:A voltage between electrodes 11 and 12, that is, the potential difference between voltage actually impressed on a surface resistance 13, is inputted as a reference voltage and an analog ground to the A/D converter 21, digitally converted, and transmitted to a central information processing circuit. The difference between said potential difference and that between stored set voltages (comparison voltage) is obtained. Together with a finger touch action to the coordinate input sheet 9, a current flows in a Y-axis side coordinate input sheet 9 through a bypass 22, and X-axis coordinate information is inputted to the A/D converter 21 from a divided voltage taking out switch 18. The central information processing circuit corrects the X-axis coordinate information based on the difference, and estimates the precise X-axis coordinate position at a finger touch input point. Switches 14-18 are changed over as broken lines show, thereby estimating the precise Y-axis coordinate position.</p> |
