| 摘要 |
A piezoelectric actuator includes a vibration plate which is joined to a flow passage unit to cover a pressure chamber formed in the flow passage unit, a piezoelectric layer arranged on the vibration plate, a first electrode arranged on the piezoelectric layer to face the pressure chamber, a second electrode arranged on the piezoelectric layer while being opposed to the first electrode, and a third area arranged in the remaining area of the piezoelectric layer opposed to the pressure chamber. A first portion of the piezoelectric layer interposed by the first and second electrodes is polarized in parallel to the thickness direction. A second portion of the piezoelectric layer disposed between the first and third electrodes in the plane direction, is polarized in parallel to the plane direction. Accordingly, there are provided the piezoelectric actuator having a high driving efficiency. |
| 主权项 |
1. A piezoelectric actuator comprising:
a vibration plate which is deformable; a base member which has a deformation acceptable section in which a deformation of the vibration plate is acceptable, and a surrounding area, surrounding the deformation acceptable section, on which the vibration plate is joined to cover the deformation acceptable section; a piezoelectric layer arranged on one surface of the vibration plate over the deformation acceptable section; a first electrode arranged in a first area of one surface of the piezoelectric layer, the first area facing the deformation acceptable section; a second electrode arranged in a second area of the other surface of the piezoelectric layer, the second area facing the first electrode; and a third electrode arranged in a third area, the third area being an area of the one surface of the piezoelectric layer different from the first area or being an area of the other surface of the piezoelectric layer different from the second area, wherein a first portion and a second portion of the piezoelectric layer are overlapped with the deformation acceptable section, the first portion being interposed by the first electrode and the second electrode in a thickness direction of the piezoelectric layer, and the second portion being interposed by the first electrode and the third electrode in a plane direction of the piezoelectric layer, wherein the first portion of the piezoelectric layer is polarized in parallel to the thickness direction, and the second portion of the piezoelectric layer is polarized in parallel to the plane direction, wherein one of the first and third areas faces a central portion of the deformation acceptable section, and wherein the other of the first and third areas faces the surrounding area, and the other of the first and third areas circumferentially surrounds the central portion of the deformation acceptable section in a plane parallel to the piezoelectric layer in an undeformed state. |
