US Patent 7126249 Electrostatic actuator including stable electrode column and wall

An electrostatic actuator allows a movable electrode to move in response to the generation of electrostatic attraction between the movable electrode and the first stable electrode wall as well as between the movable electrode and the second stable electrode wall. An insulating solid piece is interposed between the first and second stable electrode walls so as to connect the first and second stable electrode walls to each other. The insulating solid piece serves to enhance the rigidity of the first and second stable electrode walls. A higher rigidity can be established in the first and second stable electrode walls of the electrostatic actuator even if the wall thickness of the first and second stable electrode walls is reduced. The reduced wall thickness of the first and second stable electrode walls enables arrangement of the first and second stable electrode walls as many as possible within a limited space. As the number of the stable electrode walls, opposed to the movable electrode, gets increased, a larger driving force can be generated to act on the movable electrode in the electrostatic actuator.