| 摘要 |
PURPOSE:To enable the discrimination of the moving direction when a reflecting member is displaced with respect to an ultrasonic vibrator by converting an electrical signal into an ultrasonic wave to be beamed through a propagation medium while an ultrasonic vibrator is used and provided with a terminal to enable the transmitting and receiving of the electrical signal. CONSTITUTION:A continuous sine wave signal which was generated from an oscillator 12 for oscillating sine waves at the resonance frequency of an ultrasonic vibrator 3 is inputted into an ultrasonic wave position sensor 14 through a buffer circuit 13. When the continuous sine wave signal is applied to the vibrator 3 in the position sensor 14, the vibrator 3 beams ultrasonic waves continuously through an ultrasonic propagation medium 2. The ultrasonic wave travels through the medium, reaches an ultrasonic wave reflecting member 4 and then reflected to return to the vibrator 3 again. The position of the reflecting member 4 is movable longitudinally. At this point, if the frequency of the ultrasonic signal is higher by several MHzs, the ultrasonic wave travels straight as light does and is reflected. When an ultrasonic wave propagation path is relatively short, the condition of the wave front (within several tens cm) is satisfactory and the ultrasonic wave signal with the phase arrayed properly reciprocates through the medium. |
