LAYERED PIEZOELECTRIC ELEMENT AND PIEZOELECTRIC PUMP

摘要

A piezoelectric element that is capable of achieving a larger amount of displacement and in which migration between electrodes hardly occurs, is included in a piezoelectric pump. The piezoelectric pump includes a first excitation electrode opposed to a second excitation electrode via a first piezoelectric layer in a central area of a layered piezoelectric body, a third excitation electrode opposed to a fourth excitation electrode via a second piezoelectric layer and a third excitation electrode opposed to a fourth excitation electrode via the second piezoelectric layer in peripheral portions of the layered piezoelectric body. A polarization direction and a direction in which an electric field is applied in a first driving area where the first excitation electrode opposes the second excitation electrode are equal to a polarization direction and a direction in which the electric field is applied in second driving areas where the third excitation electrode opposes the fourth excitation electrode and the third excitation electrode opposes the fourth excitation electrode, and bending and displacement in the layered piezoelectric element where the second excitation electrode is isolated from the third excitation electrodes and in a thickness direction and in a central portion of the layered piezoelectric element are used to discharge liquid.