Patent ID: 7896477

Claim:
A liquid transport apparatus comprising: a base member having a surface in which a pressure chamber and a liquid flow passage are formed, the liquid flow passage being communicated with the pressure chamber and having a flow passage cross-sectional area smaller than that of the pressure chamber; and a piezoelectric actuator having a pressure-applying portion which applies a pressure to a liquid in the pressure chamber and an opening/closing portion which opens and closes the liquid flow passage, the piezoelectric actuator being formed of a stack including: a vibration plate which is arranged on the surface of the base member and which covers both the pressure chamber and the liquid flow passage; a piezoelectric material layer which is arranged on a surface, of the vibration plate, on a side not facing the base member; a first electrode which is arranged, on one of surfaces of the piezoelectric material layer, at an area thereof corresponding to the pressure chamber; a second electrode which is arranged, on one of the surfaces of the piezoelectric material layer, at an area thereof corresponding to the liquid flow passage; and a third electrode which is arranged on the piezoelectric material layer to face the first electrode and the second electrode, wherein the pressure-applying portion faces the pressure chamber, the opening/closing portion faces the liquid flow passage, and the pressure-applying portion and the opening/closing portion are arranged along the surface of the base member, wherein a low rigidity portion, at which rigidity of the stack is lower locally, is provided between the pressure-applying portion and the opening/closing portion, and wherein the low rigidity portion is a recess formed in the vibration plate at an area thereof facing a boundary between the pressure chamber and the liquid flow passage.