Patent ID: 6949869

Claim:
A piezoelectric actuator, comprising: a substrate, formed with a chamber having an opening which is defined by first edges extending in a first direction with a first dimension and second edges extending in a second direction perpendicular to the first direction with a second dimension shorter than the first dimension; a vibration plate, provided on the substrate so as to seal the opening; a first common electrode, formed on the vibration plate and to be fixed at a predetermined potential; a first piezoelectric layer, laminated on the first common electrode so as to oppose the chamber, the first piezoelectric layer extending in the first direction such that both end portions thereof in the first direction are beyond the second edges of the opening; a drive electrode, laminated on the first piezoelectric layer, to which a drive signal is supplied externally; a second piezoelectric layer, laminated on the drive electrode so as to oppose the chamber, the second piezoelectric layer extending in the first direction such that both end portions thereof in the first direction extend beyond the second edges of the opening; and a second common electrode, laminated on the second piezoelectric layer and to be fixed at the predetermined potential, wherein: the first common electrode and the second common electrode are extended beyond one of the second edges in the first direction and electrically connected at a first region; and a length in which the first piezoelectric layer extends beyond one of the second edges toward the first region is longer than a length in which the second piezoelectric layer extends beyond the one of the second edges toward the first region.