| 摘要 |
PURPOSE:To measure a material to be inspected with high accuracy and good reproducibility by providing the first front surface layer achieving the matching of acoustic impedance and the second front surface layer composed of an elastic member to the front surface of a vibrator. CONSTITUTION:The first front surface layer 2 is arranged to the front surface of a vibrator 1 and shows acoustic impedance being the geometrical mean of the acoustic impedance of said layer 2 and that of a painting film 9 and the thickness thereof 1/4 the wavelength based on the inherent frequency of the vibrator 1. The second front surface layer 3 is arranged to the front surface of the first front surface layer 2 to show the acoustic impedance equivalent to that of the painting film 9 and composed of an elastic member. By this constitution, for example, even when there is unevenness on the surface of the material 7 to be inspected having the painting film, the second front surface layer 3 can be closely adhered to the painting film 9 and, since the acoustic impedances of both of them are equal, they can be regarded to be equivalent to an integrated constitutional product. Therefore, by the matching of the acoustic impedances of the vibrator 1 and the painting film 9 due to the first front surface layer 2, a multiple echo can be suppressed and the propagation efficiency of an ultrasonic wave to the material to be inspected is enhanced and the S/N ratio of the defective echo in the material to be inspected is improved. |
