| 摘要 |
<p>PURPOSE:To provide the coordinate input device which enables input operation even at a place where a plane can not be secured by detecting a frequency-shift due to Doppler effect and computing the movement quantity of the body of the coordinate input device. CONSTITUTION:The oscillation circuit 101 of the coordinate input device outputs an AC signal of frequency f1 to a drive circuit 102 to generate a driving voltage of frequency f1. With this driving voltage, a transducer 103 generates an ultrasonic wave of frequency f1. Denoting the frequency when the ultrasonic wave of frequency f1 radiated by the transducer 103 is received by an ultrasonic wave receiver 104 as f2, the frequency shifts through Doppler effect and f1 and f2 become equal to each other. With the output 107 of a frequency comparison circuit 106 which detects that, a movement quantity detection part 111 detects the movement quantity. Two detection parts like this are prepared and movement quantities in two directions are detected to input coordinates.</p> |
