| 摘要 |
A scanner system includes a light source for producing a light beam and a multifaceted polygon for scanning the light beam in a scan plane along a scan line a predetermined distance from the polygon, such as at the surface of a photoreceptor or a document to be read. The system also includes a post-facet lens system that includes first and second elements configured to compensate for field curvature and wobble without compensating for scanner non-linearity. Preferably, the first element and second elements are so disposed that the light beam passes first through the first element and then through the second element. In addition, the first element preferably includes first and second surfaces such that the light beam passes from the first surface to the second surface, the first surface being spherical and the second surface being cylindrical with curvature in the scan plane and essential no curvature in the cross-scan plane. Furthermore, the second element preferably includes first and second surfaces such that the light beam passes from the first surface to the second surface, the first surface being spherical and the second surface being toroidal with a first curvature in the scan plane and a second curvature in the cross-scan plane.
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