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Proceedings Paper

Form, figure, and thickness measurement of freeform and conformal optics with non-contact sensors
Author(s): Scott DeFisher; Edward Fess; Greg Matthews
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Paper Abstract

Advancements in optical manufacturing technology allow optical designers to implement freeform and conformal shapes in their systems. Metrology of the shapes has traditionally been difficult, especially at the sub-micron level. Contact measuring systems typically lack the accuracy required for optical qualification and can damage the surface. Interferometric systems are unable to handle high spherical departures and may require complicated lateral calibration to generate feedback for deterministic grinding and polishing. OptiPro has developed UltraSurf, a noncontact coordinate measuring machine to determine the form, figure, and thickness of freeform and conformal optics. We integrated several non-contact sensors that acquire surface information through different optical principles. Each probe has strength and weaknesses relative to an optic’s material properties, surface finish, and figure error. The measuring probe is scanned over the optical surface while maintaining perpendicularity and a constant focal offset. Measurements of freeform and conformal shapes will be presented. The scanning method of UltraSurf and the non-contact probes will also be shown. The form, figure, and thickness data will highlight the capabilities of UltraSurf to measure freeform surfaces. Comparisons between accuracy and measureable surface departure will be made with current metrology systems such as coordinate measuring machines, interferometers, and profilometers. Additionally, methods for defining a freeform or conformal surface for metrology analysis and manufacturing will be discussed.

Paper Details

Date Published: 22 May 2015
PDF: 6 pages
Proc. SPIE 9453, Window and Dome Technologies and Materials XIV, 94530D (22 May 2015); doi: 10.1117/12.2180445
Show Author Affiliations
Scott DeFisher, OptiPro Systems Inc. (United States)
Edward Fess, OptiPro Systems Inc. (United States)
Greg Matthews, OptiPro Systems Inc. (United States)

Published in SPIE Proceedings Vol. 9453:
Window and Dome Technologies and Materials XIV
Brian J. Zelinski; Randal W. Tustison, Editor(s)

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