Abstract text

When a piezoelectric actuator, having a lower electrode, an intermediate electrode, and an upper electrode respectively on upper surfaces of a vibration plate, a lower piezoelectric layer, and an upper piezoelectric layer mutually stacked, is produced, a voltage of 30 V is applied to the upper and the intermediate electrodes, and −30 V is applied to the lower electrode so that a second active portion, which is included in portions of the piezoelectric layers interposed between the upper and the lower electrodes and from which a portion opposed to the intermediate electrode is excluded, is polarized downwardly. After that, 0 V is applied to the upper and lower electrodes, and 30 V is applied to the intermediate electrode so that a first active portion, which is included in the upper piezoelectric layer and which is interposed between the upper and the intermediate electrodes, is polarized upwardly.