Design Of A Gradient Index Binocular Objective

The color correction of a gradient index lens was investigated bythe Gradient Index Design Group at the University of Rochester. The object of the analysis was to meet the specifications of an f/3 binocular objective with a 7° field of view consisting of four homogeneous elements. A series of radial gradient singlets, each with a different base glass, was designed to meet these criteria. A study was made of the effects of varying the dispersion of the gradient on the imaging quality of the lens. It was then possible to compute the dispersion that was needed to achromatize the singlet. This calculation was compared with the dispersions in lenses produced by the ion exchange technique and these results will be reported. An extensive tolerance analysis was performed for the various designs. Each coefficient of the index distribution, the surface curvatures, and the thickness were toleranced. Also the tilt and decentration of the gradient within the singlet were toleranced. Methods of tolerancing the dispersion of the gradient were examined and tolerances in terms of relevant parameters were found.