STRUCTURAL DESIGN OF DOUBLET LENSES WITH PRESPECIFIED ABERRATION TARGETS

The authors present a systematic approach for the structural design of doublet lenses in accordance with a prespecified set of Gaussian para meters and primary aberration targets. This approach obviates the need for heuristic selection of glasses for the constituent lens elements. An identical approach is implemented for the structural design of bot h cemented and broken contact doublets. The optimization procedure is the well-known least-squares method. For facilitating convergence a se cond-derivative damping technique is utilized. Constraints are taken c are of by suitably defined continuously differentiable penalty functio ns that are treated as pseudoaberrations in optimization. A strategy f or dynamic weightage of the components of the defect function is devis ed for overcoming stagnation at the local optimum in the immediate nei ghborhood of the starting point. The strategy is also effective in con straining the glasses of the constituent elements of the doublet withi n the permissible glass domain. Some illustrative examples are given. (C) 1997 Society of Photo-Optical Instrumentation Engineers.