Abstract

Spherical fits to an aspheric surface provide a measure of the raw asphericity, give an easily generated starting point for its fabrication, and show the amount of aberration to be expected in a center of curvature test. Conoidal fits have similar uses. We have previously shown that a conoidal fit can be substantially closer than a spherical fit. We extend our methods to include fits to sections without any symmetry, even though the base surface has plane or greater symmetry. The fitting process in the conoidal case takes on many of the characteristics of a lens design optimization problem. Although it is not as complex as the typical lens design, it is difficult because the solution has to be obtained completely automatically in a reliable and reasonably efficient manner for many different kinds of surface. We describe the various techniques used to accomplish this and give examples of some actual fits so obtained.

© 1988 Optical Society of America