Patent ID: 8902440
Filing Date: 2014-12-02
Classification: G02B,G03G,G06K

Abstract:
1. An optical scanning apparatus, comprising: a light source unit emitting beam from an emitting point; a deflection unit which deflects a beam from the light source unit for scanning a surface to be scanned in a main scanning direction; an incident optical system which forms a focal line image of the emitting point; and an imaging optical system including a plurality of optical surfaces for forming an image of the emitting point by using the beam deflected by the deflection surface on the surface to be scanned or a vicinity thereof, wherein at least one of the plurality of optical surfaces has a non-circular shape in a sub-scanning section perpendicular to the main scanning direction, and a non-circular amount of the non-circular shape changes along the main scanning direction, and wherein the following conditions are satisfied: where ds(Y=0) represents a paraxial field curvature in the sub-scanning section at a center position within an effective scanning range of the surface to be scanned in the main scanning direction and ds(Y=Ymax) represents a paraxial field curvature in the sub-scanning section at a maximum image height within the effective scanning range.