| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a piezoelectric acoustic converter in which failure rate can be improved by preventing short circuit of inner and outer electrodes due to migration and protecting a ceramic layer against cracking at the time of polarization. SOLUTION: A plurality of piezoelectric ceramic layers 31 and 32 are laid in layer to form a multilayer body, and all ceramic layers 31 and 32 are polarized in the same direction in the thickness direction. An AC signal is applied between outer electrodes 33 and 34 provided on the surface and rear of the multilayer body and an inner electrode 35 provided between the ceramic layers, thus causing bending vibration of the multilayer body. A dummy electrode 36 is provided between the piezoelectric ceramic layers 31 and 32 on the outside of the inner electrode 35 through a gap G, wherein a part of the inner electrode 35 is exposed to at least one end face of the piezoelectric ceramic layer and the dummy electrode 36 is exposed to the other end face of the piezoelectric ceramic layer. The outer electrodes 33 and 34 extend to an end face of the piezoelectric ceramic layer other than that where the inner electrode 35 is exposed.</p> |
