Facet tracking correction system for laser scanners

摘要

An optical system for a beam scanning apparatus comprises a laser beam, a cylindrical first lens, a scanning mirror rotatable about an axis for deflecting and scanning the focused energy beam and a concave, toroidal mirror adapted to deflect the focused energy beam from the rotating mirror and collimate the beam. The toroidal mirror has a radius in a major axis equal to the focal length of the first lens and a radius in a minor axis equal to twice the focal length of the first lens, and is spaced from the first mirror a distance equal to the focal length of the first lens. Preferrably, the axis of rotation of the scanning mirror is non-orthogonal with respect to the direction of the beam from the first lens.