0463474 - ÚFP 2017 RIV NL eng C - Conference Paper (international conference)
Lédl, Vít - Psota, Pavel - Vojtíšek, Petr - Doleček, Roman - Dlask, Martin
Precise measurement of grinded aspherical and freeform optical surface shape by digital holography.
Proceedings of the 6th International Conference on Optical Measurement Techniques for Structures & Systems III, OPTIMESS2015. Maastricht: Shaker Publishing, 2016, s. 181-192. ISBN 978-90-423-0439-0.
[International Conference on Optical Measurement Techniques for Structures and Systems III (OPTIMESS2015) /6./. Antwerp (BE), 08.04.2015-09.04.2015]
R&D Projects: GA MŠMT(CZ) LO1206; GA TA ČR(CZ) TA03010893
Institutional support: RVO:61389021
Keywords : digital holography * RMS * aspherical and freeform surfaces
Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
Result website:
https://www.uantwerpen.be/en/conferences/optimess-2015/

A method for measurement of grinded aspherical and freeform surfaces is demonstrated in this paper. Precise measurements of semi-finished optical surfaces, like aspheres and freeforms, is still rather challenging when a high density of measurement points and a submicron precision is required. In the process of optical manufacturing every glass or ceramics element undergoes the so called generating (grinding) phase in which the element gets its basic shape. Due to the ever-growing requirements laid on the shape accuracy, the generating process is done iteratively in order to obtain the right figure before going to the next step in the manufacturing. Iterative process of grinding consists of grinding step followed by measurement step where error map is determined, if errors are too high another grinding step followed by measurement takes place until the right shape is reached. Current techniques of grinded shape measurement have many flaws, they are slow, inaccurate, the density of measurement points is low, and the level of automation is low. Another problem is that some geometries are even unmeasurable with standard methods. We proposed and developed a method based on holographic contouring with multiple illumination directions and phase shifting. This method overcomes most of the weaknesses of the current methods. Here, we demonstrate its ability to measure complex geometries in short time with precision of fraction of pm RMS.
Permanent Link: http://hdl.handle.net/11104/0262668