Abstract: A piezoelectric actuator (1) includes: a piezoelectric element (3); and a first frictional portion (10) and a second frictional portion (12) that are disposed on one principal surface (2d) of the piezoelectric element (3). The first frictional portion (10) is disposed at a position other than the antinodes of the piezoelectric element (3) at which a distance from one of the end surfaces (2a) is less than ? L, where L represents a length in the longitudinal direction of the piezoelectric element (3). The second frictional portion (12) is disposed at a position other than the antinodes of the piezoelectric element (3) at which a distance from the other of the end surfaces (2b) is less than ? L.

Abstract: In a piezoelectric element, internal stress generated in an inactive portion at the time of sintering when a piezoelectric element is fabricated or stress applied from the outside to the inactive portion is absorbed by a recess of a lower surface of a first through hole conductor and a recess of an upper surface of a second through hole conductor. Accordingly, for example, deformation, rupture, or the like of the through hole conductor is prevented, and conduction failure or disconnection of an electrode layer or a through hole conductor is prevented. Further, in the inactive portion, since a protrusion of the piezoelectric layer enters the recess of the through hole conductor, a holding force of the piezoelectric layer with respect to the through hole conductor increases, and deformation of the through hole conductor is prevented or obstructed.

Abstract: A piezoelectric actuator (1) includes: a piezoelectric element (3); and a first frictional portion (10) and a second frictional portion (12) that are disposed on one principal surface (2d) of the piezoelectric element (3). The first frictional portion (10) is disposed at a position other than the antinodes of the piezoelectric element (3) at which a distance from one of the end surfaces (2a) is less than ? L, where L represents a length in the longitudinal direction of the piezoelectric element (3). The second frictional portion (12) is disposed at a position other than the antinodes of the piezoelectric element (3) at which a distance from the other of the end surfaces (2b) is less than ? L.

Abstract: In a piezoelectric element, internal stress generated in an inactive portion at the time of sintering when a piezoelectric element is fabricated or stress applied from the outside to the inactive portion is absorbed by a recess of a lower surface of a first through hole conductor and a recess of an upper surface of a second through hole conductor. Accordingly, for example, deformation, rupture, or the like of the through hole conductor is prevented, and conduction failure or disconnection of an electrode layer or a through hole conductor is prevented. Further, in the inactive portion, since a protrusion of the piezoelectric layer enters the recess of the through hole conductor, a holding force of the piezoelectric layer with respect to the through hole conductor increases, and deformation of the through hole conductor is prevented or obstructed.