Catoptric projection system with a spherical reflecting surface

摘要

A catoptric projection system in which a projection lens and a spherical convex mirror are arranged with their optical axes intersecting at a point on the mirror at an angle with respect to each astigmatism so that an image is projected from the film plane with light after reflection from the mirror onto a light transmissive screen, thereby it being made possible to achieve a much-desired increase in the magnification of image projected on the screen without involving any increase in the magnification power of the projection lens or in the distance between the film plane and the screen. There is provided a cylindrical refracting surface disposed between the projection lens and the mirror to perform a refractive action in a plane containing both of their optical axes and to contribute an amount of astigmation which is balanced out by that of astigmatism introduced by the convex mirror.