| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide technology capable of highly accurately specifying a position in a wide range by an ultrasonic digitizer. SOLUTION: An ultrasonic wave transmitted from the tip of a pen including an ultrasonic oscillator 2 in its inside is received by sensors 3a, 3b fixed on two corners under a tablet and the position of the pen put on an optional position of the tablet is specified from the arrival time of the ultrasonic wave from the pen tip to respective sensors 3a, 3b and the propagation speed of the ultrasonic wave on the tablet and inputted to a computer or the like. The waveform of the ultrasonic wave transmitted from the osicllator 2 is encoded by a code generated from an encoding part 10 and the encoded signal is transmitted to the sensors 3a, 3b. Signals received by the sensors 3a, 3b are decoded by a decoding part 20 and time required up to the reception of the same code as the code of the ultrasonic wave transmitted from the oscillator 2 by the sensors is detected. The position of the pen is specified based on the detected time.</p> |
