Laterally driven thin film PZT actuator with high-aspect-ratio silicon beam for stroke amplification

We present a laterally driven piezoelectric actuator with stroke amplification mechanism in order to make large lateral displacement. In this work, we suggested PZT (lead zirconate titanate) actuator with a serpentine silicon spring that generates lateral displacement by increasing the vertical stiffness and reducing the lateral stiffness. The suggested laterally driven PZT actuator (bellows actuator) consists of a serpentine silicon spring and PZT/electrode layers, which are located at the edge of the serpentine silicon spring. When the PZT layer is shrunken by d31 mode, one side of the serpentine spring is compressed by the shrinkage motion of the PZT and the other side of the serpentine spring is spread out. At this time, high-aspect-ratio serpentine spring guides motion to lateral direction not vertical direction. The edge of the serpentine spring prevents the vertical motion of PZT layer, while the other edge of the serpentine spring makes stroke amplification like leverage structure. The bellows actuator shows the maximum lateral displacement of 3.93 ± 0.2 μm and vertical displacement of 0.22 ± 0.05 μm at 16 V with 1 Hz sinusoidal input signal. Lateral displacement is 16 times larger than vertical displacement at 1 Hz 10 V sinusoidal input signal. In the frequency response test, the fabricated bellows actuator shows consistent displacement from 1 Hz to 1 kHz at 10 V.