| 摘要 |
<p>PURPOSE:To stably execute the input of coordinates with high accuracy by controlling the frequency of a driving signal, which drives an oscillator, to the resonance frequency of the oscillator to correspond to a detected temperature. CONSTITUTION:A user has an oscillating pen 3 in a hand and inputs the coordinates in a position on an oscillation transmitting board 8. The oscillation transmitting board 8 transmits ultrasonic oscillation, which is received from the oscillating pen 3, to oscillation sensors 6a-6c. Signals to be detected by the sensors 6a-6c are respectively given to a signal waveform detecting circuit 9 and from an oscillation transmitting time to the sensor to be obtained by the detecting circuit 9, the position of the oscillating pen 3 is detected in an arithmetic and control circuit 1. At such a time, the temperature of an oscillator in the oscillating pen 3 is detected by a temperature sensor 12 and the frequency of the signal to drive the oscillator 4 is controlled to the resonance frequency of the oscillator 4 to correspond to the detected temperature. Thus, the input of the coordinates can be stably executed with the high accuracy.</p> |
