Abstract

In an earlier paper¹ simple criteria for color correction were derived from the dispersion formulas of Hartmann, Cauchy, Schmidt, Conrady, and Buchdahl. These criteria were used to develop a simple method for selecting optical materials that can be used for designing lens systems with color correction for at least three wavelengths. Glass combinations found by this method have been used to design superachromatic objectives of the Gauss type that are well corrected for monochromatic aberrations and color corrected at four widely separated wavelengths in a spectral band extending from the visible to the near infrared regions of the electromagnetic spectrum. The design configurations of objectives comprising six lens elements made of two different optical glasses and design examples using three glass types are presented. The performance evaluation of these designs at relative apertures of F/4 (12° field) and F/5 (20° field) is shown.

© 1989 Optical Society of America