| 摘要 |
A vibration displacement detecting system comprises a piezoelectric substrate, input- and output interdigital transducers formed on an upper end surface of the piezoelectric substrate, a signal analyzing unit connected between the input- and output interdigital transducers, and a monitor. When an input electric signal is applied to the input interdigital transducer, a leaky elastic wave is excited in the piezoelectric substrate. The leaky elastic wave is radiated effectively in the form of a longitudinal wave into a matter being in contact with a lower end surface of the piezoelectric substrate. The longitudinal wave is reflected by a thing located inside the matter, and then, is detected at the output interdigital transducer as a delayed electric signal. If the thing vibrates mechanically, the delay time of the delayed electric signal changes. Thus, a vibration displacement generated by the thing is sensed in terms of a change in the delayed electric signal at the signal analyzing unit, and displayed on the monitor.
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