The purpose of this paper is to explain in more detail some of the ideas first presented at earlier Institute of Physics and S.P.I.E. conferences, and to give an update on the work that has been done by the authors and others to develop online tutorial materials, particularly for those who do not intend to specialise in optical design. The latest additions to these courses, involving real lens design and analysis tasks, are now available on the Ancient and Modern Optics web site in unrestricted download format.
Instruments intended for use with the human eye almost always suffer from field curvature, because nearly all the components in them are of positive power. This paper will look at some standard eyepiece designs, and also one of the designs undertaken by Ancient and Modern Optics, comparing the calculated dioptre variation across the field with the subjective impressions of the user. Finally a design methodology for visual systems will be proposed which takes into account the asphericity, as well as the curvature, of the field presented to the eye, and the ability of the eye preferentially to select the best of the two astigmatic fields presented to it.
The history of lens design software is sadly littered with accounts of excellent programs which fell by the wayside for lack of support. Others evolved through various package formats to form the foundation of today's very successful commercial software. One example of this is the Imperial College lens design program developed throughout the 1960s, 1970s and 1980s by Charles Wynne, Michael Kidger, Prudence Wormell, and others. This program (best known as the Kidger Optics Ltd SIGMA) produced many excellent designs over the years. One reason was that the ray patterns and weighting factors for operands in the default merit function had been carefully honed through experience, to produce rapid convergence on the global optimum from a likely starting point. This paper describes a suite of optimisation raysets and weighted operands written in the C-like OSLO compiled macro language CCL, and modeled on the Imperial College tradition. It is available for free download from http://www.lambdares.com/techsupport/kb/index.phtml. Its prime function is to provide a fast, easily understood introduction to merit function construction for the beginner. One version is for use on OSLO EDU, the free version of OSLO, which is also available from the Lambda Research Corporation website. This paper demonstrates how OPIC can be used to locate, from a remote starting point, the global minimum of the "monochromatic quartet," the lens design problem from the SPIE 1990 International Lens Design Conference.