LINEAR IMAGE FORMING LENS OF SCANNING OPTICAL SYSTEM

摘要

PROBLEM TO BE SOLVED: To make it possible to sufficiently correct the aberrations at a diagonal direction cross-section inclined with a line image direction and orthogonal direction by forming either one face of light source side and deflector side faces as a spherical face and the other face as a progressive toric aspherical face of which the respective cross-sectional shapes parallel with a plane perpendicular to the line image inclusive of an optical axis are arcuate and of which the radius of curvature is set independently from the cross-sectional shape parallel with the line image inclusive of an optical axis. SOLUTION: The linear image forming single lens 12 is constituted by forming its one face as the progressive toric aspherical face of which the respective cross-sectional shapes parallel with the x-z plane perpendicular to the line image inclusive of the optical axis are arcuate and of which the radius of curvature is set independently from the x-y plane shape parallel with the line image inclusive of the optical axis (x). The other face is formed as a spherical face or a toric face having the axis of rotation within the plane parallel with the line image inclusive of the optical axis or a toric face which has the axis of rotation within the plane parallel with the line image inclusive of the optical axis and of which the cross-sectional shape is made non-arcuate or the progressive toric aspherical face of which the respective cross-section shapes parallel with the x-z plane perpendicular to the line image inclusive of the optical axis (x) are arcuate and of which the radius of curvature is set independently from the x-y plane shape parallel with the line image inclusive of the optical axis (x).