Patent ID: 6400488
Filing Date: 2002-06-04
Classification: G02B

Abstract:
A light beam scanner comprising:a light source unit; a polygon mirror for deflecting an incident beam from the light source unit, the polygon mirror being rotated for having a deflected beam scan a scanned surface in a main scanning direction, a rotational axis of the polygon mirror, a principal ray of the incident beam and a scanning center axis being substantially included in a first plane, the principal ray of the incident beam being substantially parallel with the scanning center axis, wherein the scanning center axis is a principal ray of the deflected beam when the deflected beam bisects a scanning angle, the scanning angle being an angle between positions of the deflected beam at a start and a finish of a scan of the scanned surface; and a housing with a light-transparent window for enclosing the polygon mirror, the window being disposed on a light path of the incident beam from the light source unit to the polygon mirror, a surface of the window being tilted with respect to a second plane that orthogonally intersects with the first plane and is parallel with a sub scanning direction.