| 摘要 |
FACET TRACKING IN LASER SCANNING Method and apparatus for improving the efficiency of laser scanning systems using a multi-faceted rotating polygon as the scanner device. In particular, an acousto-optic Bragg cell is utilized as an active optical element to both modulate and deflect an incident laser beam so that the modulated beam is caused to follow one facet of the scanner during a complete scan and to shift to the adjacent facet for the following scan. An active optical element modulates and deflects a beam of radiant energy in accordance with the information content of a drive signal applied thereto, and the beam is focused to a spot upon the surface of a medium that is sensitive to the radiant energy. A scanning device with at least one reflective surface is positioned in the path of the beam and scans the spot across the medium by rotating the reflective surface a desired angle to impart the information content of the spot to the medium. A start of scan signal is generated and, in response thereto and to the electrical signal that provides the drive signal, the drive signal causes the beam to track the reflective surface during rotation and translation thereof during scan. |
