AXIALLY ASTIGMATIC SURFACES - DIFFERENT TYPES AND THEIR PROPERTIES

Axially astigmatic surfaces have different curvatures in orthogonal di ameters. Toroidal and spherocylindrical optical surfaces are two mathe matically different special cases of axially astigmatic surfaces as no ted by Menchaca and Malacara (1986), but they are almost identical in the vicinity of the optical axis. The difference between these two sur faces increases when the distance to the optical axis increases. We st udy the general properties of astigmatic surfaces and some special int eresting cases. (C) 1996 Society of Photo-Optical Instrumentation Engi neers.