Patent ID: 7745981

Claim:
A piezoelectric actuator comprising: a ceramic sintered body comprising: an active section having a structure that is distorted during operation of the piezoelectric actuator and including piezoelectric ceramic layers and internal electrodes each disposed between adjacent ones of the piezoelectric ceramic layers included in the active section; and inert sections including piezoelectric ceramic layers and dummy internal electrodes arranged in a thickness direction, the inert sections having a structure that is not being distorted during operation of the piezoelectric actuator, the thickness direction being defined by a direction along the thickness of the piezoelectric ceramic layers included in the inert sections, each of the inert sections being disposed on at least one side of the active section in the thickness direction, each of the dummy internal electrodes being disposed between adjacent ones of the piezoelectric ceramic layers included in the inert sections; wherein a thickness of the piezoelectric ceramic layers included in the inert sections increases with increasing distance from the active section.