Catadioptric imaging systems for digital scanner

A projection optical system configured to form an image on an image plane, comprising:

• a catadioptric projection lens including first and second portions in optical communication with one another;
• said second portion configured as a catadioptric optical system including a concave mirror positioned to form an intermediate optical image at a location between elements of the second portion;
• said first portion configured as a dioptric optical system disposed to transfer light from said location to an image plane of the projection optical system to form the image thereon;
• said catadioptric projection lens configured to satisfy a condition of
• 6
• <
• 
• β
• II
• 
• 
• β
• T
• 
• <
• 20
• ,
• wherein βII denotes a magnification of the second portion and βT denotes a magnification of the catadioptric projection lens.

A projection optical system configured to form an image on an image plane, comprising:

• a catadioptric projection lens including first and second portions in optical communication with one another;
• said second portion configured as a catadioptric optical system that includes first and second negative lenses and a concave mirror to form an intermediate optical image at a location between elements of the second portion;
• said first portion configured as a dioptric optical system disposed to form an image of said intermediate optical image at the image plane;
• wherein the first negative lens has concave and convex surfaces, said concave surface of the first negative lens facing away from the concave mirror;
• and
• wherein a concave surface of the second negative lens is immediately adjacent to the concave mirror.