フリンジ電界により駆動する静電アクチュエータの動作原理の提案

Abstract

This paper proposes a novel electrostatic actuator driven by fringe electric field generated between comb-shaped electrodes on a substrate of stator. Ferroelectric teeth of floating mass on the stator are polarized by means of fringe electric field. The mass is laterally moved within the one pitch of the comb-shape electrode thanks to the electrostatic force generated between polarized charge of the tooth and that inside the electrode. Narrow pitch of comb-shaped electrodes is possible, since fluororesin is deposited on the electrode for preventing the discharge between the adjacent electrodes. The narrower pitch increases the electric field even if the applied voltage between two electrodes is rather low, achieving the higher output force. Therefore, the proposed actuator can work at low input voltage. A practical actuator was fabricated, the electrode width and pitch of which were 20 and 80μm, respectively. When the voltage of 300V was applied between the two electrodes, the maximum displacement and force were 20μm and 4mN, respectively. The force per unit area and square of voltage was 0.8N/(kV2·m2), which is not less than those of reported typical capacitive actuators.