Patent ID: 7914129

Claim:
A piezoelectric actuator which is joined to a cavity unit having a plurality of nozzles each of which jets a liquid-droplet of a liquid and a plurality of pressure chambers which correspond to the nozzles respectively and which are arranged in a row at a predetermined pitch in a predetermined row-direction, the piezoelectric actuator comprising: a plurality of ceramic sheets stacked in a predetermined stacking direction; a plurality of individual inner-electrodes which correspond to the pressure chambers respectively, and which are arranged in a row between the ceramic sheets; a common inner-electrode which is common to the pressure chambers, and which is arranged to face the individual inner-electrodes so that the ceramic sheets are sandwiched between the common inner-electrode and the individual inner-electrodes; a plurality of individual surface-electrodes arranged on a top surface, of the stacked ceramic sheets, opposite to the cavity unit, each of the individual surface-electrodes being arranged in the row-direction to be shifted with respect to one of the pressure chambers by half the predetermined pitch; a common surface-electrode which is formed 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 a ceramic sheet, of the ceramic sheets, between the individual surface-electrodes and the individual inner-electrodes, and which connect the individual surface-electrodes and the individual inner-electrodes respectively; wherein the connection electrodes include first portions, second portions, and third portions respectively; wherein each of the first portions face one of the individual surface-electrodes in the stacking direction and are connected to one of the individual surface-electrodes; wherein each of the second portions face one of the individual inner-electrodes in the stacking direction, are connected to one of the individual inner-electrodes, and are arranged in the row-direction to be shifted with respect to one of the first portions by half the pitch; and wherein the third portions connect the first portions and the second portions respectively.