Patent ID: 7462974

Claim:
An inertial driving actuator comprising: a fixing member; a moving element that is fixed to the fixing member and generates a small displacement by extension and contraction; an oscillation substrate that is fixed to the moving element and is moved linearly reciprocally by the small displacement; a moving body that is arranged on the oscillation substrate and is moved by inertia with respect to the oscillation substrate upon reciprocal movement of the oscillation substrate; a first driving electrode formed on a surface of the moving body that faces the oscillation substrate; a second driving electrode formed on a surface of the oscillation substrate that faces the moving body; a detection electrode formed on the surface of the oscillation substrate that faces the moving body, an area of a facing portion of the detection electrode and the first driving electrode changing continuously as the moving body moves; an insulating film present between the first driving electrode and the second driving electrode and the detection electrode; a frictional force controller that applies a voltage between the first driving electrode and the second driving electrode to exert an electrostatic force between them to control a frictional force generated between the oscillation substrate and the moving body; and a position detector that detects a position of the moving body with respect to the oscillation substrate on the basis of an electrostatic capacitance of the facing portion of the first driving electrode and the detection electrode.