| 摘要 |
PURPOSE:To obtain a short ultrasonic pulse by closely bringing a sound propagating medium having an uneven upper surface into contact with the upper surface of the upper electrode of a piezoelectric body. CONSTITUTION:When high frequency voltage is applied to a piezoelectric body 1 from a high frequency pulse power supply through lead wires 5a, 5b, the piezoelectric body 1 is resonated to generate an ultrasonic wave. This ultrasonic wave is divided into ultrasonic waves 18a, 18b propagating to the upper and under surfaces of the piezoelectric body 1. The ultrasonic wave 18a propagating to the under surface of the piezoelectric body 1 propagates in piping through a couplant 10 to become an ultrasonic wave effective for inspection. The ultrasonic wave 18b propagating to the upper surface of the piezoelectric body 1 propagates through the packing material 16 provided to the upper surface of said piezoelectric body 1. Since an uneven irregular reflection layer 17 is applied to the upper surface of the packing material 16, the ultrasonic wave 18b reaching the uneven surface of said layer 17 is irregularly reflected to be scattered and the ratio of the ultrasonic wave returning to the under surface of the piezoelectric body 1 is reduced. Therefore, the waveform of the ultrasonic pulse generated in the piezoelectric body 1 becomes almost same to that of a high frequency pulse and the pulse width thereof becomes short. |
