Transparent Synchronous Electrostatic Actuator for Long-Stroke Planar Motion

This paper reports a development of a transparent planar electrostatic actuator, which is useful for constructing interactive human-computer interfaces on flat panel displays. The actuator is a pair of transparent plastic films with strip electrodes in three-phase connections. Half of the electrodes in each film are X electrodes, and the rest are Y electrodes; electrostatic forces excited by applying three-phase voltage to these electrodes drive the actuator at speeds proportional to the excitation frequency. The stator film of the actuator has its X and Y electrodes alternately arranged in a four-by-four checkerboard pattern. The slider is a square film with its side twice that of a single square in the stator, with its electrodes separated by diagonal lines. A geometric analysis shows that this electrode arrangement brings position independence of overlapping areas of electrodes. The position independence gives the actuator a uniform thrust force characteristic required for long-stroke planar motion. Based on this concept, we fabricated a prototype by screen-printing. The prototype could exert approximately 100-mN thrust force with an excitation by a pair of 500-V three-phase voltages, and could travel along straight and curved paths within a 132 mm by 132 mm movable range.