Micromachined torsional scanner

A micromachined scanner assembly comprising:

• a micromachined mirror formed on a surface of a silicon wafer island supported within a first wafer section by a pair of opposed torsion bars, said mirror thus supported within the wafer section by said torsion bars exhibiting a plurality of vibrational modes including a principal torsional vibrational mode about an axis that is collinear with said torsion bars, a vertical shaking vibrational mode, a vertical rocking vibrational mode, a lateral shaking vibrational mode, and a lateral rocking vibrational mode, each such vibrational mode of said mirror having a vibrational frequency, the vibrational frequency of the principal torsional vibrational mode being lower by at least 20% than the vibrational frequency of any other vibrational mode of said mirror;
• and
• magnetic drive means for communicating a torsional force to said silicon wafer island, said magnetic drive means including:
• a conductive coil disposed on said silicon wafer island;
• and
• a magnetic field means disposed adjacent to said silicon wafer island in a galvanometric relationship with said conductive coil.

A torsional scanner assembly comprising:

• a planar frame having opposed, axially aligned torsion bars that support a planar, central mirror plate, said frame, torsion bars and mirror plate all monolithically fabricated from a planar semiconductor stress-free single crystal silicon layer of a substrate;
• said central mirror plate thus supported within the planar frame by said torsion bars having a center, defining a mirror rest plane if no external force is applied to said central mirror plate, and also exhibiting a plurality of vibrational modes including a principal torsional vibrational mode about an axis that is collinear with said torsion bars, a vertical shaking vibrational mode, a vertical rocking vibrational mode, a lateral shaking vibrational mode, and a lateral rocking vibrational mode, each such vibrational mode of said central mirror plate having a vibrational frequency, the vibrational frequency of the principal torsional vibrational mode being lower by at least 20% than the vibrational frequency of any other vibrational mode of said central mirror plate;
• and
• drive means for imparting rotary motion to said central mirror plate about the axis that is collinear with said torsion bars.