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

Kód výsledku v IS VaVaI

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Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

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

Popis výsledku v původním jazyce

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.

Název v anglickém jazyce

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

Popis výsledku anglicky

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.

Druh

D - Stať ve sborníku

CEP obor

JA - Elektronika a optoelektronika, elektrotechnika

OECD FORD obor

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Projekt

Výsledek vznikl pri realizaci vícero projektů. Více informací v záložce Projekty.

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2016

Kód důvěrnosti údajů

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

Název statě ve sborníku

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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Počet stran výsledku

12

Strana od-do

181-192

Název nakladatele

Shaker Publishing

Místo vydání

Maastricht

Místo konání akce

Antwerp

Datum konání akce

8. 4. 2015

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

000373413300018