| 摘要 |
PURPOSE:To obtain the pure thickness longitudinal vibration mode by providing a piezoelectric vibrator having lots of holes in the broadwise direction of a piezoelectric element, that is, a honey-comb piezoelectric vibrator so as to reduce the radial vibration mode oder the lateral vibration mode and its harmonic vibration mode thereby reducing spurious radiation. CONSTITUTION:A piezoelectric vibrator layer 7 is constituted that plural piezoelectric vibrators 71 are arranged with an interval along the lengthwise direction X of an acoustic damper member 1. Each of the piezoelectric vibrator 71 has lots of holes 8 with a proper area ratio in the broadwise direction of the piezoelectric element 711 and has a structure that electrodes 712, 713 are coated on both end faces in the broadwise direction of the hole opening. The shape of the holes 8 can be an optional shape such as a polygon or a cylinder. The direction of polarization of the piezoelectric element 711 is selected as the broadwise direction. Through the provision of the holes 8 above, a characteristic similar to the anisotropic property is given to the piezoelectric vibrator 71 without decreasing the dielectric constant so as to reduce the radial vibrating mode or the lateral vibrating mode thereby reducing the spurious radiation. |
