Abstract: A piezoelectric actuator that includes a multilayer body, a low-potential outer electrode, and a high-potential outer electrode. The multilayer body includes multiple alternately stacked piezoelectric ceramic layers and planar electrodes. The planar electrodes include low-potential planar electrodes electrically connected to the low-potential outer electrode and high-potential planar electrodes electrically connected to the high-potential outer electrode. The planar electrode positioned most outwardly on the side of a first main surface of the multilayer body is a low-potential planar electrode. The inner surface of this low-potential planar electrode contacts the ? side of polarization in an active region, and the outer surface of this low-potential planar electrode is exposed on an outside of the multilayer body. On the side of a second main surface of the multilayer body, a high-potential planar electrode is not exposed on the outside of the multilayer body.

Abstract: A piezoelectric actuator that includes a multilayer body, a low-potential outer electrode, and a high-potential outer electrode. The multilayer body includes multiple alternately stacked piezoelectric ceramic layers and planar electrodes. The planar electrodes include low-potential planar electrodes electrically connected to the low-potential outer electrode and high-potential planar electrodes electrically connected to the high-potential outer electrode. The planar electrode positioned most outwardly on the side of a first main surface of the multilayer body is a low-potential planar electrode. The inner surface of this low-potential planar electrode contacts the ? side of polarization in an active region, and the outer surface of this low-potential planar electrode is exposed on an outside of the multilayer body. On the side of a second main surface of the multilayer body, a high-potential planar electrode is not exposed on the outside of the multilayer body.

Abstract: A driving device that causes a movable body to move stably with minimal backward movement. The driving device includes a plate-shaped driving unit with an elastic body and a piezoelectric element joined to a main surface of the elastic body. Moreover, the movable body is disposed into a cavity of the elastic body and is moved by being pitch fed when the driving unit is driven. The driving unit vibrates with flexural vibration and one more other vibration modes or with vibration of a coupled mode in which the flexural vibration and the other vibration mode are coupled with each other.

Abstract: A driving device that causes a movable body to move stably with minimal backward movement. The driving device includes a plate-shaped driving unit with an elastic body and a piezoelectric element joined to a main surface of the elastic body. Moreover, the movable body is disposed into a cavity of the elastic body and is moved by being pitch fed when the driving unit is driven. The driving unit vibrates with flexural vibration and one more other vibration modes or with vibration of a coupled mode in which the flexural vibration and the other vibration mode are coupled with each other.