| 摘要 |
An ultrasonic switching device comprising a piezoelectric substrate, an input- and an output interdigital transducers formed on an upper end surface of the piezoelectric substrate, and a nonpiezoelectric plate, a lower end surface of the nonpiezoelectric plate being cemented on the upper end surface of the piezoelectric substrate. The output interdigital transducer has a finger-overlap zone Ri (i=1), or has N finger-overlap zones Ri (i=1, 2, . . . , N) and N-1 finger-overlap zones Qi {i=1, 2, . . . , (N-1)} between two finger-overlap zones Ri and R(i+1). Each finger-overlap zone Ri comprises three zones Ria, Rib and Rim. The finger direction of the zones Ria and Rib runs parallel with that of the input interdigital transducer. The finger direction of the zone Rim is slanting to that of the input interdigital transducer by an angle alpha . The finger direction of the finger-overlap zone Qi is slanting to that of the input interdigital transducer by an angle +/- beta . The input- and output interdigital transducers form N pairs of ultrasound propagation lanes Zia and Zib (i=1, 2, . . . , N), on the upper end surface of the nonpiezoelectric plate. If an ultrasound on an ultrasound propagation lane Zxa attenuates by touching with a finger or others on the upper end surface of the nonpiezoelectric plate, an electric signal Exb corresponding to an ultrasound propagation lane Zxb is delivered at the output interdigital transducer.
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