| 摘要 |
An ultrasonic processor operated at multiple frequencies comprises a nonpiezoelectric plate, an input IDT, an output IDT, a first piezoelectric substrate, and a second piezoelectric substrate. The input IDT with a dispersive type of electrode-finger pattern has an overlap length L and interdigital periodicities Pi (i=1, 2, . . . , m). The output IDT with a dispersive-slant type of electrode-finger pattern has the electrode-finger direction slanting to that of the input IDT by an angle theta, and also has an overlap length LP along the electrode-finger direction of the output IDT and interdigital periodicities Qi (i=1, 2, . . . , m) along the orthogonal direction to the electrode-finger direction of the output IDT. The input- and output IDTs, and the first- and second piezoelectric substrates form a transducer-unit. If one of input electric signals Si (i=1, 2, . . . , m) with frequencies fi (i=1, 2, . . . , m) corresponding to the interdigital periodicities Pi, respectively, is applied to the input IDT, a SAW is excited in the first piezoelectric substrate. The SAW is transmitted to the second piezoelectric substrate along an upper end surface of the nonpiezoelectric plate. And then, the SAW is transduced at the output IDT to electric signals Ej (j=1, 2, . . . , n), of which the phase delays linearly correlate to SAW propagation lanes Wj (j=1, 2, . . . , n) between the input- and output IDTs on the upper end surface of the nonpiezoelectric plate.
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