PURPOSE: To attain the coordinate detection with which the accuracy of detection is improved over a wide effective area by providing a magnetic plate via a nonmagnetic area on the other side surface of a tablet which delivers a signal in response to the position of an electromagnetic device set on one side of a meandering wiring.
CONSTITUTION: The X and Y axis meandering wirings and other desired wirings are printed to a tablet 6. An electromagnetic pen 7 has a coil 7a, and the sine wave voltage is applied to the coil 7a via a lead wire 7b. Thus the electromotive force is produced at each wiring on the tablet 6 in accordance with the position of the pen 7. This electromotive force is extracted every wiring and undergoes the arithmetic processing. Thus the coordinate position of the pen 7 is calculated. The 1st nonmagnetic plate 8 furnctions to keep a proper space between the coil 7a and the tablet 6. An iron plate 10 is set at the lower part of the 2nd nonmagnetic plate 9. Thus the detecting accuracy is improved greatly at an area close to a side edge. This can increase an effective area having high accuracy of detection.
YAMAGUCHI TAKESHI
IRIE AKIRA
| JPS4971836A | 1974-07-11 |