| 摘要 |
PROBLEM TO BE SOLVED: To provide a vibrator which is available in a wide-band range by using a piezoelectric substance to form an active part of the vibrator, polarizing the active part in the longitudinal direction of a substrate and also applying an electric field in the longitudinal direction of the substrate to make the substrate excite a fundamental vibration of a longitudinal vibration mode. SOLUTION: The inactive parts 28 are formed at both end sides of a substrate 12 of a piezoelectric resonator 10, and the resonance frequency and differenceΔF between the resonance frequency and the anti-resonance frequency are controlled, via the adjustment of both parts 28. That is, the band width of the resonator 10 is adjusted by polishing the end face of the substrate 12 in its longitudinal direction or adding the mass and the like. Furthermore, it is possible to control the resonator 10 by adjusting the number of layers of an active part 26. In other words, the part 26 contains the piezoelectric layers and the internal electrodes 14 which are alternately stacked on each other, and therefore the thickness of a single layer is inversely proportional to the number of layers, when only the number of layers is changed against the same total thickness of the part 26. As a result, the number of degrees of freedom for designing can be increased for the capacity of the resonator.
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