Abstract: A high frequency film actuator for the micropump is proposed based on the bridge-type mechanism. The bridge-type mechanism contributes to the improvement in the amplification ratio, and the linkage mechanism is employed to eliminate the output drift. The ideal model and the elastic theory are respectively used to establish the kinematic characteristics and the deformation of the film actuator in order to investigate the displacement amplification ratio and the output drift. It is possible for the rotational symmetric configuration to reduce the thermal deformations. By the finite element analysis in ANSYS software and prototype experiments the mechanical design and the displacement amplification ratio are evaluated. The prototype was made by MEMS technology, and had the maximum output displacement of 50 μm and the displacement amplification ratio of 23. If the geometric relation agrees with the developed conditions, the output displacement is only relative to the mean of the input displacements, and no output radial displacement exists because of the difference among the inputs.

Key words: film actuator, bridge-type mechanism, elastic theory, displacement amplification ratio