OPTICAL PROJECTION SYSTEM

An optical projection system of unit magnification for transmitting a real erect image of an object from an object plane to an image plane, comprises a plurality of lenses having parallel optical axes and being arranged in one or more rows. Each lens comprises three or four lens elements arranged along a common optical path extending between the object and image planes, and includes at least two aperture masks which subtend light rays from the axial and off-axis object points in the object plane. These aperture masks are arranged in positions where the image-forming pencil of light rays passing through the lens has a relatively large cross-section.