| 摘要 |
A thickness-extensional piezoelectric resonator using a harmonic of a thickness-extensional vibration mode has a compact size, large electric capacity, and small variations in resonance characteristics, and is not affected by the stray capacitance of a circuit board. The thickness-extensional piezoelectric resonator includes a substantially rectangular-plate piezoelectric body, a first excitation electrode and a second excitation electrode disposed on individual surfaces of the piezoelectric body, and an internal electrode inside of the piezoelectric body. Portions where the first excitation electrode, the second excitation electrode and the internal electrode overlap define a resonating portion. In the length direction of the piezoelectric body, a vibration-attenuating portion is defined at each side of the resonating portion, whereas in the width direction, the vibration-attenuating portion is not provided at each side thereof. In addition, a relationship |Dr-Di|=Di/10 is satisfied, where Dr is the thickness of piezoelectric layers between the excitation electrodes and the internal electrode, Di is substantially equal to T/N, where T is the thickness of the piezoelectric body and N is the order of harmonics of the width extensional vibration mode.
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