BUCKLED ACTUATOR WITH ENHANCED RESTORING FORCE

An electrostatic actuator device including a stationary support (11) and a buckled, moveable support mounted positioned to enter into contact with the stationary support (13). At least three electrodes (15, 17, 19) are employed. The first (15) is mounted on the moveable support (13) and a second (17) electrode is on the stationary support. A third electrode (19) is mounted on one of the supports such that the electrodes are positioned to form two pairs of electrodes for electrostatic attraction therebetween. The electrodes are powered by a voltage supply (25, 27, 29) to provide electrostatic attraction between pairs of electrodes and move them into electrostatic contact. The buckled electrode (13) has a shape configured to transmit a restoring force to its portion in contact with stationary support upon application of voltage to another pair of electrodes. The preferred voltage provides a two phase driving force including a voltage to the first pair of electrode for a period of time in a cycle of operation and a voltage to the second pair of electrodes for a period of time in the same cycle, preferably with an interim period of time with no voltage applied after each applicatio n of voltage.