| 摘要 |
<p>PURPOSE:To miniaturize an image input part and to simplify an input operation by providing microphones for receiving ultrasonic waves from an image input pen on various positions, detecting time difference and deciding the coordinate of the input pen. CONSTITUTION:In the main body 1 of an input device, microphones 6-1 and 6-2 are provided on various positions so as to receive the ultrasonic waves from an ultrasonic wave generating part 5 fitted to an image input pen 2. When the ultrasonic waves are received, a signal matched with the timing of driving the ultrasonic wave generating part 5 is supplied from a timing signal generation circuit to a time difference detection circuit to output the detecting signal. Then, the time difference detection circuit calculates difference between the timing of inputting the timing signal and the timing of outputting the detecting signal from the microphone 6-1. The difference between the timing of generating the timing signal and the timing of outputting the detecting signal from the microphone 6-2 is similarly calculated and according to these kinds of difference, coordinate calculation circuit calculates a distance between the respective microphones.</p> |
