Superlens, 300 mm Aperture, Four(4) Focal Length Missile Tracking Telescope, Used to Illustrate Tolerance Assignment Techniques

ASSIGNING TOLERANCES FOR MINIMUM COST

CONSULTING, SHORT COURSES, AND SOFTWARE

The assignment of tolerances to the various dimensions and parameters of an optical system is a CRITICAL element in determining the resulting performance and cost of the system. This has historically been complex and ill-defined and therefore a distasteful aspect which the designer has had to deal with in one way or another. Much of the tolerancing of systems in practice has been done by art and experience more than by scientific calculation. We make the ENGINEERING principles as simple and clear as possible so that they may be applied in a straightforward manner. We use the term "engineering" to imply that practical approximations based on empirical data are used to reduce the problem to terms that can be handled in the real world. That is to further imply that we are dealing here with the application of optical design to produce a functional set of hardware as opposed to the theory and/or science of lens design as an exact and abstract study.

We discuss what makes up the cost of a lens and the effects of tolerances and other factors of that cost. This results in a lens cost estimation formula. We describe the interactions of lenses and lens cells from the tolerance viewpoint. We explain the principles whereby the system tolerances can be determined which will give the minimum cost system which meets the performance requirements. We include examples from real life of the application of the principles.

Tolerencing Optical Systems Papers

Ref. R. R. Willey and M. E. Durham, "Maximizing production yield and performance in optical instruments through effective design and tolerancing," SPIE CR43, Optomechanical Design, Paul R, Yoder, ed., (1992).

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