Patent ID: 6999216
Filing Date: 2006-02-14
Classification: G02B

Abstract:
1. A reflective scanning optical system, comprising: a light source unit for emitting a beam; a polygon mirror having a plurality of reflecting surfaces parallel to its rotation axis, for reflecting and dynamically deflecting the beam emitted by the light source unit; and a single fθ optical element having a first surface for refracting the beam dynamically deflected by the polygon mirror and a second surface for reflecting the beam refracted by the first surface and thereby letting the beam emerge from the first surface, for converging the beam on a scan target surface, wherein magnification m wherein the light source unit is set so that a central axis of the beam incident on the polygon mirror from the light source unit is in a plane orthogonal to the rotation axis of the polygon mirror and out of an effective scan range of the beam dynamically deflected by the polygon mirror in regard to a main scanning direction, and wherein the fθ optical element is placed so as to set each reflecting surface of the polygon mirror and the scan target surface optically conjugate with each other in regard to the auxiliary scanning direction and separate the beam incident upon the first surface and the beam emerging from the first surface from each other in the auxiliary scanning direction.