Title
Design of a machine for the universal non-contact measurement of large free-form optics with 30 nm uncertainty
Author
TNO Industrie en Techniek
Henselmans, R.
Rosielle, P.C.J.N.
Steinbuch, M.
Saunders, I.
Bergmans, R.
Contributor
Stahl, H.P. (editor)
Publication year
2005
Abstract
A new universal non-contact measurement machine design for measuring free-form optics with 30 nm expanded uncertainty is presented. In the cylindrical machine concept, an optical probe with 5 mm range is positioned over the surface by a motion system. Due to a 2nd order error effect when measuring smoothly curved surfaces, only 6 position measurement errors are critical (nanometer level). A separate metrology system directly measures these critical errors of the probe and the product relative to a metrology frame, circumventing most stage errors. An uncertainty estimation has been performed for the presented design, including a calibration uncertainty estimation and a dynamic analysis. Machine dynamics certainly cause relative motion between probe and product, but due to the non-contact nature of the measurement and the short metrology loop, these motions do not cause significant measurement errors. The resulting shape measurement error for aspheres up to medium free-forms is between 24 and 37 nm, and 30 - 85 nm for medium to heavily free-form surfaces. The suitability of the proposed design is herewith confirmed. A detailed design and a prototype of the machine are currently being developed.
Subject
Aspherical
Free-form
Measurement
Metrology
Non-contact
Optics
Estimation
Machine design
To reference this document use:
http://resolver.tudelft.nl/uuid:9caaeb1f-7045-4471-98a1-efc961f6cfce
TNO identifier
239039
Publisher
SPIE
ISSN
0277-786X
Source
Optical Manufacturing and Testing VI, 31 July - 1 August 2005, San Diego, CA, USA, 5869 (5869), 1-12
Document type
conference paper