Design of linear-motion microactuators using piezoelectric thin films

Three types of microactuator for linear displacement are presented which use piezoelectric thin films for the electrical-to-mechanical energy conversion process. One actuator uses a folded-path or meander-line geometry to produce horizontal tethered linear displacements. The second geometry uses a number of unimorph bars arranged in a planar format and mechanically connected in series to produce a tethered displacement perpendicular to the plane containing the unimorphs. The third actuator uses an inertial recoil mechanism in conjunction with an electrostatic clamp to produce incremental stepping motion. Sufficient repetition of the stepping sequence produces virtually unlimited travel range, being limited by practical considerations such as electrical connections. Electromechanical models for all three actuators are developed and are used to quantitatively estimate the performance of microactuators designed to a particular set of dimensions. Fabrication procedures for the microactuators have been developed and the status of the fabrication efforts is presented.