| 摘要 |
<p>PURPOSE:To reduce an error to half by vibrating a vibrating means by plural pulses so that a vibration which is detected obtains a vibration having plural peaks, and calculating a coordinate data from the time of said plural peaks are detected. CONSTITUTION:By a pulse 4-1 which is sent to a vibrator pen 1-1, a piezoelectric vibrator in the vibrator pen 1-1 executes an electro-mechanical conversion, and an elastic wave is generated in a glass plate 1-3. In such a state, two pulse trains are driven by a combined driving waveform at suitable time intervals so that an envelope 4-2 is obtained on the glass plate 1-3. With regard to peaks P1, P2 of the waveform 4-2, a crest and a trough of the wave which forms the envelope are aligned so that the peak P1 and the peak P2 go to a part (a) and a part (b), respectively. In such a case, by detecting the Tp4 and Tp5, {Tp4+(Tp5-Tp4)/2} is set as a position of this detected waveform. In such a way, it goes to a 1/2 period portion of the wave which forms the envelope, an error goes to a 1/2 period portion, and an error range is reduced exactly to 1/2.</p> |
