| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a coordinate reader capable of omitting a power source of a coordinate input tool main body while suppressing increase of device cost. SOLUTION: Power supply to a pen is performed by plural loop coils 23 arranged in vertical and horizontal directions to detect an alternate magnetic field to be generated by the pen. Specifically, electromotive force is generated at a coil of the pen by electromagnetic induction by impressing high frequency voltage to the loop coil 23 to detect the alternate magnetic field. Namely, the loop coil 23 to detect the alternate magnetic field is commonly used as a coil of a power supply device to supply power to the pen. Thus, the power source to generate the power to the pen main body is dispensed and the increase of the device cost is simultaneously suppressed since no separate coil for power supply to the pen is required.</p> |
