| US 7,482,728 B2 | ||
| Electrostatic actuator including a switching circuit which selectively sets one of a moving mode and first and second holding modes and driving method therefor | ||
| Akihiro Koga, Kawasaki (Japan); Masayuki Sekimura, Chofu (Japan); and Toshikatsu Akiba, Kisarazu (Japan) | ||
| Assigned to Kabushiki Kaisha Toshiba, Tokyo (Japan) | ||
| Filed on Sep. 23, 2005, as Appl. No. 11/233,091. | ||
| Claims priority of application No. 2004-324389 (JP), filed on Nov. 08, 2004. | ||
| Prior Publication US 2006/0097672 A1, May 11, 2006 | ||
| Int. Cl. H02N 1/00 (2006.01); G02B 7/04 (2006.01); G02B 7/08 (2006.01) | ||
| U.S. Cl. 310—309 [348/357; 396/75; 318/116] | 8 Claims |
| 1. An electrostatic actuator, comprising:
a first substrate equipped with a first stator electrode and a first dielectric film covering the first stator electrode;
a second substrate equipped with a second stator electrode and a second dielectric film covering the second stator electrode,
the second stator electrode being positioned to face the first stator electrode;
a movable part having first and second surfaces that are positioned to face the first and second stator electrodes, respectively,
the movable part being provided with first and second movable electrodes formed on the first and second surfaces of the movable
part, respectively; and
a driving circuit including a switching circuit which selectively sets one of
a moving mode in which first and second moving modes are alternatively switched to move the movable part between the first
and second substrates and
first and second holding modes in which the movable part is held on the first and second substrates, respectively,
wherein the switching circuit is so switched as to
apply a first potential to each of the first movable electrode and the second stator electrode and also apply a second potential
differing from the first potential to the first stator electrode during the first moving mode in which the movable part is
moved toward the first substrate,
apply the first potential to each of the second movable electrode and the first stator electrode and also apply the second
potential to the second stator electrode during the second moving mode in which the movable part is moved toward the second
substrate,
keep one or both of the first stator electrode, and the first movable electrode in an electrical floating state during the
first holding mode in which the movable part is kept attached to the first substrate, and intermittently apply the first potential
to the first movable electrode and apply the second potential to the first stator electrode to maintain the first holding
mode, and
keep one or both of the second stator electrode and the second movable electrode to be electrically floated in an electrical
floating state during the second holding mode in which the movable part is kept attached to one of the first and second substrates,
and intermittently apply the first potential to the second movable electrode and apply the second potential to the second
stator electrode to maintain the second holding mode.
|