| 摘要 |
PURPOSE:To enable the detection of elastical change with good sensitivity, by obtaining image information from the phase difference between both electrodes of a transducer consisting of a piezoelectric substrate and a transmitting receiving arch shaped interdigital electrode and performing scanning by the relative movement with an object to be inspected. CONSTITUTION:An electric signal is applied to the arch shaped interdigital electrode 16 of a ramming wave device 10 from a signal input terminal 18 to emit a sound wave (a vertical polarized wave) while the sound wave emitted according to formula wherein theta is the angle formed between the normal line of a solid-liquid boundary surface and the emitting direction of a sound wave, VS is the speed of the sound wave 22 propagating through a liquid and VL is the propagation speed of a leaked ramming wave propagating through a piezoelectric body 12 is reflected from the surface or interior of an object 20 to be inspected and received by the arch shaped interdigital electrode 14 to be converted to an electric signal. Further, the phase comparison between a transmitting signal and a receiving signal is performed by a phase comparator 30 and the phase difference dependent on the thickness (d) of a liquid is displayed to a display device 40 according to the address of a reflection point P. Furthermore, the scanning of the reflection point P is mechanically performed in the plane parallel to a piezoelectric body 10 and the frequency of the electric signal applied to a terminal 18 is changed to change the emitting direction theta of the sound wave. |
