This paper describes the procedure followed in reoptimizing a laser scan lens to eliminate two undesirable elements of the concentric-meniscus type. The continual reappearance of two weak meniscus elements during several reoptimizations had suggested that there were unneeded elements in the lens. When we reduced the number of elements from six to five and reoptimized, both meniscus elements became ordinary elements, and diffraction-limited performance was obtained. Fitting the existing lens into the optimum minimum region of the Los Alamos National Laboratory optimization code was the most difficult part of the procedure.
Morris M. Klein,
"Optimization To Eliminate Two Lens Elements That Have Undesirable Shapes," Optical Engineering 27(12), 121027 (1 December 1988). https://doi.org/10.1117/12.7978670