Importance

Loading Importance Indicators...

Abstract

An image reading optical system, including: an imaging optical system used for imaging a slit area of a document and includes an optical element having different cross section shapes in a main scanning direction and in a sub-scanning direction; an aperture stop; and an optical phase changing filter disposed adjacent to the aperture stop and including a phase lead area and a phase delay area, in which the optical phase changing filter includes a surface shape component that is symmetric only with respect to a predetermined plane including a surface normal at the center of the incident beam and one of the main scanning direction and the sub-scanning direction, and with respect to a surface that includes the surface normal at the center of the incident beam and is perpendicular to the predetermined plane, one side is the phase lead area, and another side is the phase delay area.

Loading the Abstract Image...

First Claim