Development of Microactuators Driven by Liquid Crystals : 4th Report, Experiments of Driving a Plate(Fluids Engineering)

Abstract

For the purpose of developing liquid crystalline microactuators, we have performed experiments to drive a plate which is movable in its planar direction, by applying an electric field to a liquid crystal confined with two parallel plates. We have succeeded in moving the upper plate of an experimental cell continuously by applying a square-wave electric field. With the increase in the frequency of the electric field, the speed of the upper plate increases abruptly, reaches the maximum value, and decreases gradually. The maximum value is 120μm/s at the frequency of 175Hz when the applied voltage is 10V, the duty ratio is 5%, and the cell gap is 10μm. This frequency is considerably high compared to the response characteristics of the liquid crystal used in this experiment. It is supposed from the fact that the molecules do not return to the initial posture when the electric field is released. The effects of the applied voltage, the duty ratio and the cell gap on the speed of the upper plate have been studied and an interesting result is that the speed of the upper plate does not monotonically increase with the applied voltage but reaches a constant value.