oSIST prEN ISO 14880-3:2023

SLOVENSKI STANDARD
oSIST prEN ISO 14880-3:2023
01-junij-2023
Optika in fotonska tehnologija - Vrste mikroleč - 3. del: Preskusne metode za
optične lastnosti, razen odstopanja valovne fronte (ISO/DIS 14880-3:2023)
Optics and photonics - Microlens arrays - Part 3: Test methods for optical properties
other than wavefront aberrations (ISO/DIS 14880-3:2023)
Optik und Photonik - Mikrolinsenarrays - Teil 3: Prüfverfahren für optische Eigenschaften
außer Wellenfrontaberrationen (ISO/DIS 14880-3:2023)
Optique et photonique - Réseaux de microlentilles - Partie 3: Méthodes d'essai pour les
propriétés optiques autres que les aberrations du front d'onde (ISO/DIS 14880-3:2023)
Ta slovenski standard je istoveten z: prEN ISO 14880-3
ICS:
31.260 Optoelektronika, laserska Optoelectronics. Laser
oprema equipment
oSIST prEN ISO 14880-3:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 14880-3:2023

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oSIST prEN ISO 14880-3:2023
DRAFT INTERNATIONAL STANDARD
ISO/DIS 14880-3
ISO/TC 172/SC 9 Secretariat: DIN
Voting begins on: Voting terminates on:
2023-04-11 2023-07-04
Optics and photonics — Microlens arrays —
Part 3:
Test methods for optical properties other than wavefront
aberrations
Optique et photonique — Réseaux de microlentilles —
Partie 3: Méthodes d'essai pour les propriétés optiques autres que les aberrations du front d'onde
ICS: 31.260
This document is circulated as received from the committee secretariat.
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
ISO/CEN PARALLEL PROCESSING
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
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STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
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WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 14880-3:2023(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. © ISO 2023

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oSIST prEN ISO 14880-3:2023
ISO/DIS 14880-3:2023(E)
DRAFT INTERNATIONAL STANDARD
ISO/DIS 14880-3
ISO/TC 172/SC 9 Secretariat: DIN
Voting begins on: Voting terminates on:

Optics and photonics — Microlens arrays —
Part 3:
Test methods for optical properties other than wavefront
aberrations
Optique et photonique — Réseaux de microlentilles —
Partie 3: Méthodes d'essai pour les propriétés optiques autres que les aberrations du front d'onde
ICS: 31.260
This document is circulated as received from the committee secretariat.
COPYRIGHT PROTECTED DOCUMENT
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
© ISO 2023
ISO/CEN PARALLEL PROCESSING
THEREFORE SUBJECT TO CHANGE AND MAY
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
NOT BE REFERRED TO AS AN INTERNATIONAL
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on STANDARD UNTIL PUBLISHED AS SUCH.
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WHICH REFERENCE MAY BE MADE IN
Reference number
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NATIONAL REGULATIONS.
Website: www.iso.org ISO/DIS 14880-3:2023(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
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ii
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PROVIDE SUPPORTING DOCUMENTATION. © ISO 2023

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oSIST prEN ISO 14880-3:2023
ISO/DIS 14880-3:2023(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Substrate test . 1
5 Microscope test method .1
5.1 Principle . 1
5.2 Measurement arrangement and test equipment . 2
5.2.1 General . 2
5.2.2 Test system . 3
6 Procedure .4
6.1 General . 4
6.2 Measurement of effective back or front focal length . 4
6.3 Measurement of chromatic aberration . 4
6.4 Measurement of the uniformity of the focal spot positions . 5
7 Results and uncertainties . 5
8 Coupling efficiency, imaging quality.6
9 Test report . 6
Annex A (informative) Measurements with wavefront measuring systems .8
Annex B (informative) Confocal measurement of effective backor front focal length of lens
array .10
Annex C (informative) Coupling efficiency, imaging quality .12
Annex D (normative) Measurement of the uniformity of the focal spot positionsof a
microlens array .13
Bibliography .14
iii
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oSIST prEN ISO 14880-3:2023
ISO/DIS 14880-3:2023(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 172, Optics and Photonics, Subcommittee
SC 09, Laser and electro-optical systems.
This second edition cancels and replaces the first edition (ISO 14880-3:2006), which has been
technically revised.
The main changes are as follows:
— Introduction revised.
— Reference documents and numbering updated.
A list of all parts in the ISO 14880 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
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oSIST prEN ISO 14880-3:2023
ISO/DIS 14880-3:2023(E)
Introduction
This document specifies methods of testing optical properties, other than wavefront aberrations, of
microlens arrays. Examples of applications for microlens arrays include three-dimensional displays,
coupling optics associated with arrayed light sources and photo-detectors, enhanced optics for liquid
[12][13][15][16]
crystal displays, and optical parallel processor elements .
The testing of microlenses is in principle similar to testing any other lens. The same parameters need
to be measured and similar techniques used. However, in many cases the measurement of very small
lenses presents practical problems which make it difficult to use the standard equipment that is
[15][16]
available for testing normal size lenses .
The market in microlens arrays has generated a need for agreement on basic terminology and test
methods. Standard terminology and clear definitions are needed not only to promote applications
but also to encourage scientists and engineers to exchange ideas and new concepts based on common
understanding.
This document contributes to the purpose of the series of ISO 14880 standards which is to improve the
compatibility and interchangeability of lens arrays from different suppliers and to enhance development
of the technology using microlens arrays.
Characteristic parameters are defined and examples of applications given in ISO 14880-1, Vocabulary.
It has been completed by a set of three other International Standards, i.e. Part 2, Test methods for
wavefront aberrations, Part 3, Test methods for optical properties other than wavefront aberrations and
Part 4, Test methods for geometrical properties.
This document describes the measurement of 1) focal length, 2) coupling efficiency, 3) imaging quality
and 4) focal spot positions.
The focal length of the microlens is defined more precisely in 14880-1 as effective back (front) focal
length.
The measurement of effective back (front) focal length is described in the body of this part of ISO 14880
and the use of an alternative technique, interferometry, is described in Annex A.
Measurement of the focal length of an array of microlenses, using a confocal technique, is described in
the main body and Annex B.
Coupling efficiency and imaging quality are discussed in Annex C.
Measurement of the focal spot positions of an array of microlenses in parallel, using the Shack-Hartmann
technique, is described in Annex D.
Wavefront aberrations and characteristics other than optical properties are specified in ISO 14880-2
and ISO 14880-4 and ISO/TR 14880-5.
v
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oSIST prEN ISO 14880-3:2023

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oSIST prEN ISO 14880-3:2023
DRAFT INTERNATIONAL STANDARD ISO/DIS 14880-3:2023(E)
Optics and photonics — Microlens arrays —
Part 3:
Test methods for optical properties other than wavefront
aberrations
1 Scope
[1]
This document specifies methods for testing optical properties, other than wavefront aberrations, of
microlenses in microlens arrays. It is applicable to microlens arrays with very small lenses formed on
one or more surfaces of a common substrate and to graded-index microlenses.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 14880-1, Optics and photonics — Microlens arrays — Part 1: Vocabulary
ISO 10110-5, Optics and photonics — Preparation of drawings for optical elements and systems — Part 5:
Surface form tolerances
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 14880-1 apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Substrate test
The optical quality of the substrate contributes to the quality of the focal positions defined by the
microlenses and shall be quantified in accordance with ISO 10110-5.
5 Microscope test method
5.1 Principle
The basic principle is to locate, by optical means, the surface of the microlens under test. The effective
back (front) focal length is determined by measuring the axial displacement necessary to locate the
focal position.
1
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oSIST prEN ISO 14880-3:2023
ISO/DIS 14880-3:2023(E)
5.2 Measurement arrangement and test equipment
5.2.1 General
The testing of microlenses is similar in principle to testing larger lenses. In many cases however, the
measurement of very small lenses presents practical problems which make it difficult to use standard
equipment. In general, two optical techniques can be used. One is based on microscopy, the other is
[2]
based on interferometry .
The first technique uses a microscope to locate, by focusing, the vertex of the microlens. The effective
back (front) focal length is deduced from a measurement of the displacement necessary to refocus the
microscope on the image of a distant source as shown in Figure 1.
A focusing aid in the microscope such as a split-field focusing graticule enables the featureless vertex of a
microlens to be more readily located when viewing with reflected light. For focal length measurements
the distant point source may be the end face of an illuminated optical fibre or an illuminated test
graticule. Tests may be performed with white light or monochromatic illumination.
The second technique uses wavefront sensing to locate the test surface or the centre of curvature. The
location test may be carried out with the help of one of the following devices:
— Fizeau interferometer,
— Twyman-Green interferometer,
— lateral shearing interferometer, or
— Shack-Hartmann device.
[1][2]
These are more fully described in ISO 14880-2 and ISO/TR 14999-1. One advantage of interferometry
is that for strongly aberrated lenses, the variation in focal length with aperture radius can be readily
deduced from the interference patterns. A disadvantage is that tests are restricted to the wavelength of
the interferometer light source.
Key
1 distant point source
2 substrate and microlens producing focused spot
3 microscope objective
4 axial adjustment of microscope to locate lens surface and focus
5 beamsplitter
6 source for focus location on lens surface
7 imaging array
Figure 1 — A collimated source and microscope used to measure the effective back or front
focal length of a microlens
2
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oSIST prEN ISO 14880-3:2023
ISO/DIS 14880-3:2023(E)
Clauses 5 to 9 concentrate on the microscope technique while an interferometric technique is described
in Annex A and a Shack-Hartmann technique in Annex D.
The confocal measurement of the effective focal lengths of lens arrays is described in Annex B.
5.2.2 Test system
5.2.2.1 General
The test system consists of a microscope fitted with displacement transducers, suitable light source,
test object, microscope video camera, monitor and image analyser (line intensity scan).
5.2.2.2 Microscope
A microscope fitted with a focusing aid such as a split-image rangefinder is required to enable focus
settings to be made on a featureless surface such as the vertex of the microlens surface. The mechanical
design shall allow the distant point source or test graticule to be placed below the stage carrying the
test lens. Ideally, the test lens should be supported with no additional optical component such as a glass
plate between it and the distant point source or test graticule. The displacement of the test surface
relative to the microscope objective is measured with a calibrated displacement transducer.
The numerical aperture (NA) of the microscope objective shall be larger than the numerical aperture of
the test lens at the focal point.
5.2.2.3 Light source
A light source emitting radiation in the band of wavelengths or at a specific wavelength required for
the test shall be used. The properties of the light source shall be described in the experimental results
report.
White light can be provided by a quartz-halogen lamp in combination with a suitable aperture stop.
Narrow band filters can be used where a restricted range of wavelengths is required. A laser or LED
can be used for monochromatic illumination and higher intensities.
5.2.2.4 Test object (Test graticle)
The distant point source can be approximated using the end face of an illuminated optical fibre. The
distant point source shall be placed on axis with the lens and at an effectively large distance to enable
the focal length to be determined.
Alternatively, the object may be a graticule. This enables the optical properties at particular spatial
frequencies and field angles to be studied.
The detection of the focus spot may be susceptible to under-sampling by the detector array.
The distant point source or test graticule used shall be described in the documentation of the test
report.
5.2.2.5 Image display
If the image generated by the microscope is relayed by a video camera to a video display, an electronic
intensity display can be used to assist in locating the posi
...