Patent ID: 6104521
Filing Date: 2000-08-15
Classification: G02B

Abstract:
A scanning optical system, comprising:a light source that emits a beam of light;a first optical system which receives said beam of light, said first optical system changing a cross-sectional shape of said beam of light into an oblong shape extending along a main scanning direction, said first optical system comprising a lens which has a first surface on one side of said lens and a second surface on another side of said lens, said first surface being a toric surface having a rotational axis extending in a sub-scanning direction perpendicular to the main scanning direction and said second surface being a curved surface having a curvature at least in the main scanning direction, at least one of said first and second surfaces comprising a sub-scanning plane aspherical surface, said sub-scanning-plane aspherical surface having a rotational axis extending in the sub-scanning direction;a light deflector that deflects said oblong-shaped beam of light in the main scanning direction; anda second optical system which receives a beam of light deflected by said light deflector and focuses said deflected beam of light onto a scanning surface,said sub-scanning plane aspherical surface correcting a spherical aberration in a sub-scanning plane that extends in the sub-scanning direction, said spherical aberration being caused by said second optical system.