Patent ID: 7963637

Claim:
A method of driving a piezoelectric actuator which is constituted of a lower electrode film, a piezoelectric film and an upper electrode film that are layered successively onto a diaphragm, the piezoelectric film being oriented in an orientation direction from the lower electrode film toward the upper electrode film, the method comprising the steps of: applying an electric field to the piezoelectric film in a direction opposite to the orientation direction of the piezoelectric film while continuously changing an intensity of the electric field from a first electric field intensity to a second electric field intensity, the first electric field intensity being smaller than a coercive electric field of the piezoelectric film, the second electric field intensity being larger than the coercive electric field of the piezoelectric film; and applying another electric field to the piezoelectric film in a direction that is parallel with the orientation direction of the piezoelectric film when the piezoelectric actuator is not being driven.