Rotational oscillatory optical scanning device

In an optical instrument wherein an assembly consisting of a plurality of optical elements is scanned relative to a base frame about a rotation axis which is external to said elements and to the space between said elements, while said elements remain substantially motionless with respect to each other, said instrument including a counterrotating counterbalance which rotates in the rotational direction opposite said assembly, a vibration reducing apparatus for scanning said assembly comprising:

• an arm to which said assembly is attached;
• means rotating said arm with respect to said base frame about said rotation axis which is external to said elements and to the space between said elements;
• a second counterbalance;
• means for connecting at least said assembly, said arm and said second counterbalance so as to form a superassembly of components adapted to rotate as unit about said rotation axis, said superassembly having a center of mass, the center of mass of said elements and the center of mass of said second counterbalance being located on opposite sides of said rotation axis, and said second counterbalance being located such that said rotation axis passes through the center of mass of said superassembly thereby to provide balancing of said superassembly on said rotation axis;
• and
• power transducing means for applying a time varying torque to said assembly so that said assembly rotates reciprocally about said rotation axis thereby resulting in substantial reduction in the transmission of vibration to said base frame.

In a scanning device including a base frame, a scanned element reciprocally scanned with respect to said base frame in an arc about a rotation axis external to said element, said device including a counterrotating counterbalance adapted to rotate in the opposite rotational direction from said element, means scanning said element while reducing vibration of said base frame comprising:

• an arm spacing said element from said rotation axis;
• a second counterbalance;
• means for connecting at least said element, said arm and said second counterbalance so as to form a superassembly of components adapted to rotate as unit about said rotation axis, said superassembly having a center of mass, the center of mass of said element and the center of mass of said second counterbalance being located on opposite sides of said rotation axis, and said second counterbalance being located within said superassembly such that said rotation axis passes through the center of mass of said superassembly thereby to provide balancing of said superassembly on said rotation axis;
• and
• power transducing means for applying time varying torque to said superassembly such that an associated reaction torque is applied directly to said counterrotating counterbalance instead of to said base frame, such that said element can rotate reciprocally about said rotation axis while substantially reducing the transmission of vibration to said base frame.