| 摘要 |
<p>PURPOSE:To eliminate a cord from a pen and to improve the operability by arranging plural long magnetic substances each wound with a coil at a prescribed interval in parallel and using the inductance change in each coil so as to detect the position of the pen when the pen approaches. CONSTITUTION:When the pen 20 incorporating a rod magnet is positioned on the magnetic substances 11a-11h, since the angle between the magnetic flux and each magnetic substance in the lengthwise direction is smaller in a magnetic substance closer to the pen, the inductance of the coil of the magnetic substance closest to the pen is minimized. Thus, the inductance of each coil (12a-12h) is converted into a voltage signal by a converting circuit 30 and a signal selection circuit 40, a voltage difference (differential component) among the coils is taken to calculate the coordinate where the difference is zero.</p> |
