| 摘要 |
An optical scanning device for raster scanning applications based on galvanometric scanner technology incorporates a nonlinear biasing element, such as a nonlinear magnetic or mechanical spring to assist in the acceleration and deceleration of the motor shaft at the turn around points of the sawtooth motion. The galvanometric scanning device includes a moving magnet motor using more than four poles, e.g., eight poles. The moving magnet motor has a plurality of laminations each having a number of teeth, e.g., eight, extending inward toward the rotor and having coils mounted thereon. In one embodiment, coils are mounted on every other tooth. The motor is driven with a fourth order polynomial sawtooth command signal to reduce resonances caused by high acceleration and deceleration. In addition, the motor may be driven by pulse width modulation to reduce power dissipation. The positioning sensor mirror is coupled to the back of the scanning mirror to reduce structural resonance between the positioning sensor mirror and the scanning mirror. The positioning sensor mirror may be mounted on the scanning mirror or may be integrally formed on the back of the scanning mirror, e.g., by polishing. The rotor and scanning mirror are supported by only two bearings, one bearing supporting the rotor and an outboard bearing supporting the scanning mirror, which advantageously reduces cross axis wobble.
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