Precise measurement of grinded aspherical and freeform optical surface shape by digital holography

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61389021%3A_____%2F16%3A00463474" target="_blank" >RIV/61389021:_____/16:00463474 - isvavai.cz</a>

Result on the web

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DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Precise measurement of grinded aspherical and freeform optical surface shape by digital holography

Original language description

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.

Czech name

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Czech description

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Type

D - Article in proceedings

CEP classification

JA - Electronics and optoelectronics

OECD FORD branch

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Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2016

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Article name in the collection

Proceedings of the 6th International Conference on Optical Measurement Techniques for Structures & Systems III, OPTIMESS2015

ISBN

978-90-423-0439-0

ISSN

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e-ISSN

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Number of pages

12

Pages from-to

181-192

Publisher name

Shaker Publishing

Place of publication

Maastricht

Event location

Antwerp

Event date

Apr 8, 2015

Type of event by nationality

WRD - Celosvětová akce

UT code for WoS article

000373413300018