Abstract

Strategies for selecting or creating starting designs vary depending on the designer and the problem. We describe several such techniques and include the basic approach, its advantages, and its limitations. Starting from previous designs is the simplest approach if relevant designs can be found. Most designs come from the literature, including in-house lens design libraries. When the literature is inadequate, the design must be created from scratch. Scratch design approaches vary from "minimum spherical bending" for the simplest cases to application of the designer's knowledge of past designs to provide a "guess" as to the overall configuration type, number of elements, shape, and materials. Experienced designers are often able to sketch the general form they think may apply and then use paraxial ray tracing to adjust the design to the desired values for a starting point. The y–y bar diagram is a tool for synthesizing the first-order properties of optical configurations that are limited by packaging requirements (e.g., periscope and laser beam delivery systems). One can directly specify on the y–y bar diagram such parameters as pupil and image locations, magnification, minimum beam size, and lens barrel diameter constraints. The diagram may then be modified to satisfy these requirements and packaging constraints; detection of system infeasibility is also possible. The diagram does not directly provide aberration performance, but an experienced user can usually infer this and other similar attributes.

© 1990 Optical Society of America