Patent ID: 7808150
Filing Date: 2010-10-05
Classification: B81B,H02N

Abstract:
1. An actuator comprising: a supporting substrate having an opening; a spacer provided on the supporting substrate; a pair of supporting portions each secured to the supporting substrate through the spacer; a mass portion being arranged between the pair of supporting portions, through elastic connecting portions above the opening of the supporting substrate in such a manner that the mass portion can be rotated with respect to the supporting portions about the elastic connecting portions serving as a rotational axis; a first movable comb electrode and a second movable comb electrode provided in pair at the opposite sides of the mass portion symmetrically with the rotational axis of the mass portion; a first fixed portion and a second fixed portion respectively provided outside the opening of the support substrate symmetrically with the rotational axis of the mass portion and directly affixed to the supporting substrate with no intervention of the spacer so that the first fixed portion and the second fixed portion are in parallel with the mass portion in the thickness direction thereof but at a lower position than a position of the mass portion; and a first fixed comb electrode integrally formed with or connected to the first fixed portion and meshing with the first movable comb electrode in a spaced-apart relationship and a second fixed comb electrode integrally formed with or connected to the second fixed portion and meshing with the second movable comb electrode in a spaced-apart relationship; wherein a part of each of the first fixed comb electrode and the second fixed comb electrode overlaps with a part of the corresponding movable comb electrode in a state where no alternating voltage is applied therebetween in a thickness direction of each of the first fixed comb electrode and the second fixed comb electrode when viewed from the rotational axis of the mass portion, wherein the first fixed comb electrode is initially deflected so as to be inclined toward the supporting substrate with respect to the supporting substrate, and the second fixed comb electrode is initially deflected so as to be inclined away from the supporting substrate with respect to the supporting substrate, and wherein the mass portion is rotated by applying alternating voltages across each of the first movable comb electrode and the second movable comb electrode and the corresponding fixed comb electrode.