Patent ID: 7719163

Claim:
An actuator comprising: a supporting substrate; a spacer provided on the supporting substrate; first supporting portions each secured to the supporting substrate through the spacer; a mass portion having a movable comb electrode and having a rotational axis and adapted to be rotatable with respect to the first supporting portions; elastic connecting portions for interconnecting the mass portion to the first supporting portions, respectively, in such a manner that the mass portion can be rotated with respect to the first supporting portions about the rotational axis; at least one second supporting portion secured to the supporting substrate through the spacer; at least one fixed portion directly affixed to the supporting substrate with no intervention of the spacer so that the fixed portion is in parallel with the mass portion and the second supporting portion in the thickness direction but a lower position than a position of the mass portion and the second supporting portion, and the fixed portion being arranged between the mass portion and the second supporting portion; a fixed comb electrode integrally formed with or connected to the fixed portion and meshing with the movable comb electrode in a spaced-apart relationship; and a bridge portion for directly or indirectly connecting the fixed portion to the second supporting portion, wherein the fixed portion is affixed to the supporting substrate in a state that the fixed portion is deflected toward the supporting substrate with respect to the second supporting portion while bending the bridge portion, thereby initially deflecting the fixed comb electrode so that a part of the fixed comb electrode overlaps in parallel with a part of the movable comb electrode in a state where no alternating voltage is applied therebetween in a thickness direction of the fixed comb electrode when viewed from the rotational axis of the mass portion, wherein the mass portion is rotated by applying alternating voltages across the movable comb electrode and the fixed comb electrode.