| 摘要 |
<p>PURPOSE:To improve the detecting accuracy of coordinates with a simple constitution by using two sheets having electrodes formed at two counter sides of resistance sheet having uniform surface resistance and superposing these sheets to make the sides of the electrodes orthogonal to each other. CONSTITUTION:The currents conducting to lead wires 28-31 are equal to the currents conducting to feedback resistances 48-51. Therefore the voltage change generated at output terminals 44-47 of amplifiers 32-35 when the non-conductive state between transparent resistance sheets 21 and 22 changes to a short circuited state at a contact point 54 is proportional to the current conducting to the wires 28-31. Therefore the horizontal and vertical coordinates of the point 54 are obtained from the voltage change ratio generated between output terminals 44 and 45 and output terminals 46 and 47 respectively. Then the offset voltage of the amplifiers 34 and 35 is set at zero with no contact secured between lead wires 30/31 and electrodes 25/26. In such a way, the vertical coordinates of the point 54 can be obtained by a coordinate discriminating circuit 52 from the output voltage ratio between amplifiers 34 and 35.</p> |
