Thin-Film PZT Lateral Actuators With Extended Stroke

Many microelectromechanical system applications require large in-plane actuation forces, with stroke lengths ranging from submicrometer to tens of micrometers in distance. Piezo electric thin films are capable of generating very large actuation forces, but their motion is not easily directed into lateral displacement in microscale devices. A new piezoelectric thin-film actuator that uses a combination of piezoelectric unimorph beams to generate lateral displacement has been developed. The piezoelectric actuators were fabricated using chemical-solution-derived lead zirconate titanate thin films. These actuators have demonstrated forces greater than 7 mN at displacements of nearly 1 mum, with maximum stroke lengths at 20 V greater than 5 mum in a 500-mum-long by 100-mum-wide actuator. Force and displacement capabilities can be manipulated through simple changes to the actuator design, while actuator nonlinearity can produce dramatic gains in work capacity and stroke length for longer actuators.