Design and fabrication of a parylene-based tunable micromotion amplifier

Presented is a parylene-based tunable micromotion amplifier. Large displacements are produced when long beams are buckled by an axial load generated by attached thermal actuators. Buckled beams can be used as bistable beams and are switched by thermal actuators on both sides of the beam. The amplitude of bistable displacement is determined according to the amount of displacement created by the attached thermal actuators. The parylene-based straight beams can effectively reduce the required force more than silicon-based beams can. Two experimental devices involving silicon- and parylene-based buckled beams were designed and fabricated to verify this theory. The parylene-based buckled beams amplified the thermal actuator displacement by 6 μm by applying 10.5 V to 52 μm of movement at the centre of the buckled beam, and displaced 78 μm of movement between the two equilibrium positions. The attached thermal actuators of the parylene-based device amplified displacement 13-fold. The attached thermal actuators of the silicon-based buckled beams generated less than 1 μm of movement by applying 10.5 V, thus failing to form bistable beams. This design is suitable for application in devices capable of large in-plane displacement and low driving forces.