Patent ID: 7166951

Claim:
An electrostatic actuator, comprising: a first stationary member provided with a first electrode group which includes at least three first stationary electrodes each having a first width and sequentially arranged at a pitch in a predetermined direction; a second stationary member arranged to face the first stationary member and provided with a second electrode group which includes at least three second stationary electrodes each having the first width and arranged at the pitch in the predetermined direction; a movable member configured to be movable in the predetermined direction, which is arranged between the first and second stationary members and is provided with first and second movable electrodes faced to the first and second stationary electrodes, respectively; a signal generator configured to generate one of first and second voltage signals having different first and second timing patterns, respectively, and to apply the one of the first and second voltage signals alternately to the first and second stationary electrodes, the movable member being driven in response to the first voltage signal if the first and second stationary electrodes are arranged to be substantially in phase, and in response to the second voltage signal if the first and second stationary electrodes are arranged to be out of phase; a detector configured to detect a movement of the movable member to generate a movement signal in accordance with an application of the one of the first and second voltage signals; and a setting circuit configured to set the one of the first and second timing patterns in response to the movement signal.