Patent ID: 7136547

Claim:
An apparatus for directing a radiation beam comprising: a movable member supported for movement by a fixed member such that a coefficient of friction exists between the movable member and the fixed member, said movable member including an optical element fixedly attached thereto; a magnetic element fixedly attached to the movable member; a magnetically permeable stator element that is stationary with respect to the movable member, said stator element and said magnetic element mutually generating a magnetic traction force there between; a current coil wound around at least a portion of the stator element; and a current driver for providing a current in the current coil thereby inducing an electromagnetic force in the stator element, said electromagnetic force acting on the magnetic element for controlling movement of the optical element; wherein said magnetic traction force in combination with the coefficient of friction provides a clamping force for holding the movable element in a stationary orientation when no current is passing through the current coil.