Scalable cascaded snap-in actuators for large-stroke displacements

This paper will focus on the design, and first measurements of a cascaded in-plane parallel plate snap-in actuator. The actuator is based on a rather simple micro-fabrication process and can achieve a total displacement of several tenths of microns. Compared to classical non-cascaded transducer device based on parallel plates or comb-drive actuator, the actuation voltage is relatively low due to the snap-in phenomenon of electrostatic actuators. The electromechanical response of such a device is sequential. The fabricated 4-stage device shows a total stroke of 75 mum at 60 V. It is possible to easily increase the total stroke of the actuator by increasing the number of stages. Only one input electrode is required. Simulations with CoventorWare showed easy scalability of the concept for up to 19 stages with a total displacement of 350 mum.