Patent ID: 8061820

Claim:
A fluid ejection system, comprising: a substrate having a chamber formed therein; a membrane that forms a wall of the chamber and is operable to expand or contract the chamber by flexing; and an actuator supported on the membrane, the actuator comprising: a piezoelectric layer disposed between a drive electrode layer and a reference electrode layer, wherein: 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 a 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; and the reference electrode layer comprises a reference electrode spanning at least an area covered by the drive electrode, where creation of a voltage differential between the drive electrode and the reference electrode generates an electric field in the continuous planar piezoelectric material, and the electric field results in actuation of the continuous planar piezoelectric material to flex the membrane.