SIST EN ISO 14880-4:2025

SLOVENSKI STANDARD
01-januar-2025
Nadomešča:
SIST EN ISO 14880-4:2006
Optika in fotonska tehnologija - Vrste mikroleč - 4. del: Preskusne metode za
geometrične lastnosti (ISO 14880-4:2024)
Optics and photonics - Microlens arrays - Part 4: Test methods for geometrical properties
(ISO 14880-4:2024)
Optik und Photonik - Mikrolinsenarrays - Teil 4: Prüfverfahren für geometrische
Eigenschaften (ISO 14880-4:2024)
Optique et photonique - Réseaux de microlentilles - Partie 4: Méthodes d'essai pour les
propriétés géométriques (ISO 14880-4:2024)
Ta slovenski standard je istoveten z: EN ISO 14880-4:2024
ICS:
31.260 Optoelektronika, laserska Optoelectronics. Laser
oprema equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 14880-4
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2024
EUROPÄISCHE NORM
ICS 31.260 Supersedes EN ISO 14880-4:2006
English Version
Optics and photonics - Microlens arrays - Part 4: Test
methods for geometrical properties (ISO 14880-4:2024)
Optique et photonique - Réseaux de microlentilles - Optik und Photonik - Mikrolinsenarrays - Teil 4:
Partie 4: Méthodes d'essai pour les propriétés Prüfverfahren für geometrische Eigenschaften (ISO
géométriques (ISO 14880-4:2024) 14880-4:2024)
This European Standard was approved by CEN on 5 August 2023.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 14880-4:2024 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 14880-4:2024) has been prepared by Technical Committee ISO/TC 172 "Optics
and photonics" in collaboration with Technical Committee CEN/TC 123 “Lasers and photonics” the
secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by May 2025, and conflicting national standards shall be
withdrawn at the latest by May 2025.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 14880-4:2006.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 14880-4:2024 has been approved by CEN as EN ISO 14880-4:2024 without any
modification.
International
Standard
ISO 14880-4
Second edition
Optics and photonics — Microlens
2024-11
arrays —
Part 4:
Test methods for geometrical
properties
Optique et photonique — Réseaux de microlentilles —
Partie 4: Méthodes d'essai pour les propriétés géométriques
Reference number
ISO 14880-4:2024(en) © ISO 2024

ISO 14880-4:2024(en)
© ISO 2024
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 14880-4:2024(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Coordinate system . 3
5 Test methods . 3
5.1 Pitch and surface modulation depth measurement .3
5.1.1 Use of stylus instrument .3
5.1.2 Use of confocal microscope .5
5.2 Physical thickness.8
5.2.1 Principle .8
5.2.2 Set-up and preparation .8
5.3 Radius of curvature.8
5.3.1 Principle .8
5.3.2 Measurement arrangement and test equipment .9
5.4 Surface preparation of microlens array for measurement .11
6 Procedure .11
6.1 Measurement of pitch and surface modulation depth (lens sag) .11
6.1.1 Preliminary measurements.11
6.2 Making measurements and interpreting the results .11
6.3 Measurement of physical thickness . 12
6.4 Measurement of radius of curvature . 12
7 Results and uncertainties .12
8 Test report .13
Annex A (informative) Measurement with a Fizeau interferometer system . 14
Annex B (informative) Uniformity of array spacing . 17
Bibliography .20

iii
ISO 14880-4:2024(en)
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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 9,
Laser and electro-optical systems, in collaboration with the European Committee for Standardization (CEN)
Technical Committee CEN/TC 123, Lasers and photonics, in accordance with the Agreement on technical
cooperation between ISO and CEN (Vienna Agreement).
This second edition cancels and replaces the first edition (ISO 14880-4:2006), which has been technically
revised.
The main changes are as follows:
— Introduction revised;
— Updated the references to terms defined in 14880-1;
— Figure 8 replaced;
— References 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
ISO 14880-4:2024(en)
Introduction
Examples of applications for microlens arrays include three-dimensional displays, coupling optics associated
with arrayed light sources and photo-detectors, enhanced optics for liquid crystal displays, and optical
parallel processor elements.
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. It has been
completed by a set of three other International Standards, i.e. ISO 14880-2, ISO 14880-3 and ISO 14880-4.
The measurement of physical characteristics of pitch and surface modulation depth can be made using
a stylus instrument and non-contact optical probe system. Physical thickness can be measured with a
micrometer. The measurement processes are described in the body of this document.

v
International Standard ISO 14880-4:2024(en)
Optics and photonics — Microlens arrays —
Part 4:
Test methods for geometrical properties
1 Scope
This document specifies methods for testing geometrical properties 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
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 14880-1 and the following 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/
NOTE 1 The symbols adopted for this document are chosen for clarity in this application to microlens arrays but
some may not be those commonly used for surface texture measurement.
NOTE 2 The parameters P , P and h are used in this document to describe geometrical parameters encountered in
x y
the measurement of surface texture. P , P are spacing parameters and are defined as the average value of the length
x y
of the mean line section containing a profile peak and adjacent valley. An amplitude parameter, h, is defined as the
average difference between peak of the lens profile and the rim. Figure 1 illustrates the geometrical properties of
microlens arrays which are to be measured.
3.1
pitch
P , P
x y
distance between the centres of adjacent lenses which may vary across the array and will vary with direction
Note 1 to entry: See Figure 1.
Note 2 to entry: The pitch is expressed in millimetres.
[SOURCE: ISO 14880-1:2019, 3.4.1.5]
Note 3 to entry: For a stylus instrument this will generally equate to the mean width of the profile elements, Rsm,
calculated from the roughness profile (see ISO 21920-2:2021, 3.1.14.3).

ISO 14880-4:2024(en)
3.2
surface modulation depth
h
peak-to-valley variation of the surface height
Note 1 to entry: See Figure 1.
Note 2 to entry: For a purely refractive microlens, this will be the same as the lens sag.
Note 3 to entry: The surface modulation depth is expressed in millimetres.
[SOURCE: ISO 14880-1:2019, 3.4.1.8]
Note 4 to entry: For stylus instruments this will generally equate to Rz (see ISO 21920-2:2021, 3.1.14.3).
3.3
physical thickness
T
c
maximum local thickness of the array
Note 1 to entry: See Figure 1.
Note 2 to entry: The physical thickness is expressed in millimetres.
[SOURCE: ISO 14880-1:2019, 3.4.1.9]
3.4
radius of curvature
R
c
distance from the vertex of the microlens to the centre of curvature of the lens surface
Note 1 to entry: See Figure 1.
Note 2 to entry: The radius of curvature is expressed in millimetres.
[SOURCE: ISO 14880-1:2019, 3.3.3]
Note 3 to entry: For rotationally invariant microlenses or cylindrical microlenses.
Key
1 substrate
T physical thickness
c
R radius of curvature
c
P , P pitch
x y
h surface modulation depth (lens sag)
Figure 1 — Geometrical parameters of microlens arrays

ISO 14880-4:2024(en)
4 Coordinate system
To measure the geometrical properties of a microlens array, a Cartesian coordinate system is used, as shown
in Figure 2 (ISO 14880-1:2019, Figure 1). In a right-handed Cartesian set, the X- and Y-axis lie in the substrate
plane and the X-axis provides the direction of trace. The Z-axis is the outward direction from the material to
the surrounding medium.
Key
1 substrate
2 microlens
3 light paths
Figure 2 — Microlens array with a Cartesian coordinate system
5 Test methods
5.1 Pitch and surface modulation depth measurement
5.1.1 Use of stylus instrument
5.1.1.1 Principle
[1][2][3][4]
The basic principle using a stylus instrument is to obtain a profile of the surface of the array . Care
shall be taken to ensure that the profile passes through the centre of each lens and that the stylus remains
in contact with the surface throughout the measurement process. This enables the pitch and surface
modulation depth to be determined.
5.1.1.2 Set-up and preparation
The measurement of the geometrical characteristics of a microlens array is similar in principle to the
measurement of any surface using a stylus instrument. A typical stylus instrument consists of a stylus
that physically contacts the surface and a transducer to convert its vertical movement into an electrical
signal. Other components can be seen in Figure 3 and include the following: a pick-up, driven by a motor and
gearbox, which draws the stylus over the surface at a constant speed; an electronic amplifier to boost the
signal from the stylus transducer to a useful level; a device for recording the amplified signal or a computer
that automates the data collection.
The part of the stylus in contact with the surface of the array is usually a diamond tip with a carefully
manufactured profile. Owing to their finite shape, some styli on some arrays may not penetrate into valleys
and will give a distorted or filtered measurement of the surface. The effect of the stylus forces can have a

ISO 14880-4:2024(en)
significant influence on the measurement results. Too high a force can cause damage to the surface of the
array. Too low a force and the stylus will not stay reliably in contact with the surface.
The stylus instrument shall be used in an environment that is as free as possible from dust, vibration and
direct sunlight in a location where the ambient temperature is maintained in the range 20 °C ± 5 °C (with
a condensation-free humidity below 70 % relative humidity). Remove any gross contamination from the
surface of the instrument preferably by blowing the surface with filtered air. Any oil or grease may be
removed using a suitable solvent.
Due consideration shall be given for testing under more adverse conditions.
Key
1 base
2 fixture
3 microlens under test
4 stylus
5 probe (pick-up)
6 measurement loop
7 column
8 drive unit
Figure 3 — Elements of a typical stylus instrument
The electrical unit on the stylus instrument shall be switched on at least one hour before any measurements
take place. This will allow time for the instrument to stabilize (the manufacturer’s instructions will normally
specify a minimum stabilization time for a given instrument). Calibration of the instrument is essential prior
to measurement. Before calibration of the instrument takes place the stylus should be checked for signs of
wear or damage. A damaged stylus tip can lead to serious errors.
After measurement of the calibration artefact the indicated value shall be compared with the value attached
to the test object. If the measured value differs from the value that is shown on the calibration certificate
then recalibration is required.

ISO 14880-4:2024(en)
5.1.1.3 Stylus size and shape
It is important that the dimension and shape of the stylus are chosen appropriately as this can affect the
accuracy of the traced profile in a number of ways. On arrays with deep, narrow valleys the stylus may not
be able to penetrate fully to the bottom because either the tip radius or the flank angle of the stylus is too
large. In such cases, the value of the surface modulation depth will be smaller than the true value. The ideal
stylus shape is a cone with a spherical tip. This usually has a cone angle of either 60° or 90° with a typical tip
radius of 1 µm, 2 µm, 5 µm or 10 µm.
5.1.2 Use of confocal microscope
5.1.2.1 Principle
[14]
The confocal principle can be used for the measurement of surface topography . Depth is discriminated by
moving the surface of the object through focus and measuring the reflected intensity using a detector and
confocal pinhole. When the object point lies at the focus, the maximum intensity is detected whereas the
signal is reduced when the object point is displaced from the f
...