Measurement of inner centration of an asphere with computer generated holograms compared to an optical profiler

J.-M Asfour; M. Wendel

doi:10.1117/12.2643129

3 October 2022 Measurement of inner centration of an asphere with computer generated holograms compared to an optical profiler

J.-M Asfour, M. Wendel

Author Affiliations +

Proceedings Volume 12221, Optical Manufacturing and Testing XIV; 122210V (2022) https://doi.org/10.1117/12.2643129
Event: SPIE Optical Engineering + Applications, 2022, San Diego, California, United States

Abstract

Centration measurements of lenses usually require two measurements of the center of curvature, one for each side of a lens. For aspheres, the situation is more complex, because an aspherical surface defines a set of centers of curvature for each diameter of the aspherical surface. This makes the measurement and its interpretation more complex. We present three different methods to measure the inner centration of an asphere and discuss accuracies and practical aspects. One approach is the use of a Computer-Generated Hologram in combination with a Fizeau-type interferometer. The CGH is split into a ring area for testing the first side of the asphere and a central circular CGH which is optimized for testing the spherical backside of the lens at the same time. The Zernike coefficients of the two interferometric measurements can be used to back calculate the inner centration. The second approach is based on an optical profiler using multi-wavelength interferometry. It collects surface data from the first and the second surface after another, by turning the lens surfaces using an additional tooling where common fiducials for both sides enable a precise mechanical relation. A third option is also based on this optical profiler, enabling the measurement of the back-surface through the lens. We have applied all three methods for testing one specific asphere and compare and discuss the results we have obtained.

Conference Presentation

Citation Download Citation

J.-M Asfour and M. Wendel "Measurement of inner centration of an asphere with computer generated holograms compared to an optical profiler", Proc. SPIE 12221, Optical Manufacturing and Testing XIV, 122210V (3 October 2022); https://doi.org/10.1117/12.2643129

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available