Patent ID: 7449816

Claim:
A piezoelectric actuator comprising: a vibration plate; a supporting member having a non-interference portion which does not interfere with deformation of the vibration plate, and a joining portion joined to the vibration plate; a piezoelectric layer arranged on a side of the vibration plate opposite to the supporting member; a first electrode arranged on a surface of the piezoelectric layer on a side of the vibration plate; a second electrode arranged at an area facing the non-interference portion, the area being on a surface of the piezoelectric layer on a side opposite to the vibration plate; a wiring which has a contact point and which extends, on the surface of the piezoelectric layer on the side opposite to the vibration plate, from the second electrode to an area facing the joining portion; and a wiring member which has a terminal joined, with an electrically conductive material, to the contact point of the wiring, and which supplies drive voltage to the second electrode; wherein a cavity is provided at a portion of at least one of the vibration plate and the joining portion, the portion facing the wiring and being disposed between the second electrode and the contact point.