| 摘要 |
PURPOSE:To secure the control for the resonance response by applying the AC electric field to the piezoelectricceramic plate which features the thickness vertical vibration and the thickness shear vibration. CONSTITUTION:Piezoelectric ceramic plate 1 features the thickness vibration, and electrodes 2 and 3 are attached to the upper surface of plate 1 each. Then the output terminals of AC power source 4 are connected to electrodes 2 and 3. Here the AC field is applied to plate 1 featuring the thickness vertical vibration, and thus the voltage featuring the opposite polarity to the polarization direction is applied at least for the half cycle to give the control to the degree of polarization. As a result, both the resonance frequency and the antiresonance frequency can be controlled. On the other hand, with application of the AC field to plate 1 featuring the thickness shear vibrationl the AC voltage is applied in the direction which is orthogonal to the polarization direction. Thus part of the polarization is turned toward the application direction of the AC voltage, and as a result the degree of polarization varies to ensure the control for each frequency. In other words, the resonance response of ceramic plate 1 can be controlled with application of the AC field. |
