Patent ID: 8425014

Claim:
A method for actuating a pumping chamber, comprising: generating a voltage differential for a time period between a drive electrode and a reference electrode of a piezoelectric actuator to expand the pumping chamber, wherein: the pumping chamber is a cavity formed in a substrate, the cavity being covered by a membrane that is operable to expand or contract the pumping chamber by flexing; the piezoelectric actuator is supported on the membrane and comprises a piezoelectric layer disposed between a drive electrode layer and a reference electrode layer; the piezoelectric layer comprises a continuous planar piezoelectric material spanning the chamber and having a uniform poling direction that is substantially perpendicular to the continuous planar piezoelectric material; the drive electrode layer comprises the drive electrode in contact with the continuous planar piezoelectric material, the drive electrode being in the shape of a ring, disposed over a peripheral portion of the membrane, and being the sole drive electrode over the membrane in the drive electrode layer; the reference electrode layer comprises the reference electrode spanning at least an area covered by the drive electrode; and the creation of the voltage differential between the drive electrode and the reference electrode generates an electric field in the continuous planar piezoelectric material, the electric field resulting in actuation of the continuous planar piezoelectric material to flex the membrane.