Patent ID: 7497558

Claim:
A piezoelectric actuator on which connection terminals of signal lines transmitting a drive signal to the piezoelectric actuator are connected, the actuator comprising: a plurality of ceramic sheets stacked in a predetermined stacking direction; a plurality of individual inner-electrodes which are arranged in a row in a predetermined row-direction between the ceramic sheets; a common inner-electrode which is arranged to face the individual inner-electrodes so that one ceramic sheet, among the ceramic sheets, is sandwiched between the common inner-electrode and the individual inner-electrodes; a plurality of individual surface-electrodes which are arranged on a top surface of the stacked ceramic sheets, and which are connected to the individual inner-electrodes respectively; a common surface-electrode which is arranged on the top surface of the stacked ceramic sheets, and which is connected to the common inner-electrode; and a plurality of connection-electrodes which are arranged on another ceramic sheet, among the ceramic sheets, between the individual surface-electrodes and the individual inner-electrodes, which face in parallel to the individual surface-electrodes respectively in the stacking direction, and which are arranged in a row in the row-direction corresponding to the individual surface-electrodes respectively, each of the connection-electrodes connecting one of the individual surface-electrodes and one of the individual inner-electrodes, and having an area enough to cover one of the individual surface-electrodes corresponding to each of the connection-electrodes; wherein two individual surface-electrodes, among the plurality of individual surface-electrodes, which are adjacent to each other in the row-direction, are connected to two connection electrodes, among the plurality of connection electrodes, corresponding to the two individual surface-electrodes, at mutually different positions in an orthogonal direction orthogonal to the row-direction, respectively.