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Proceedings Paper

Design of systems involving easily measurable aspheres
Author(s): Paul E. Murphy; Dave Stephenson; Andrew E. W. Jones; Greg W. Forbes
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Paper Abstract

Aspheric surfaces provide significant benefits to an optical design. Unfortunately, aspheres are usually more difficult to fabricate than spherical surfaces, making the choice of whether and when to use aspheres in a design less obvious. Much of the difficulty comes from obtaining aspheric measurements with comparable quality and simplicity to spherical measurements. Subaperture stitching can provide a flexible and effective test for many aspheric shapes, enabling more cost-effective manufacture of high-precision aspheres. To take full advantage of this flexible testing capability, however, the designer must know what the limitations of the measurement are, so that the asphere designs can be optimized for both performance and manufacturability. In practice, this can be quite difficult, as instrument capabilities are difficult to quantify absolutely, and standard asphere polynomial coefficients are difficult to interpret. The slope-orthogonal “Q” polynomial representation for an aspheric surface is ideal for constraining the slope departure of aspheres. We present a method of estimating whether an asphere described by Q polynomials is measurable by QED Technologies’ SSI-A system. This estimation function quickly computes the testability from the asphere’s prescription (Q polynomial coefficients, radius of curvature, and aperture size), and is thus suitable for employing in lens design merit functions. We compare the estimates against actual SSI-A lattices. Finally, we explore the speed and utility of the method in a lens design study.

Paper Details

Date Published: 15 October 2013
PDF: 10 pages
Proc. SPIE 8884, Optifab 2013, 88841D (15 October 2013); doi: 10.1117/12.2031897
Show Author Affiliations
Paul E. Murphy, QED Technologies, Inc. (United States)
Dave Stephenson, JENOPTIK Optical Systems (United States)
Andrew E. W. Jones, QED Technologies, Inc. (United States)
Greg W. Forbes, QED Technologies, Inc. (United States)

Published in SPIE Proceedings Vol. 8884:
Optifab 2013
Julie L. Bentley; Matthias Pfaff, Editor(s)

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