SIST EN ISO 14880-3:2006

Optics and phonotics - Microlens arrays - Part 3: Test methods for optical properties other than wavefront aberrations (ISO 14880-3:2006)

ISO 14880-3:2006 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.

Optik und Photonik - Mikrolinsenarrays - Teil 3: Prüfverfahren für optische Eigenschaften außer Wellenfrontaberrationen (ISO 14880-3:2006)

Dieser Teil der ISO 14880 legt Prüfverfahren für die Messung optischer Eigenschaften von Mikrolinsen in Mikrolinsenarrays fest, mit Ausnahme von Wellenfrontaberrationen. Die Norm gilt für Mikrolinsenarrays mit sehr kleinen Linsen, die auf einer oder mehreren Oberflächen eines gemeinsamen Substrats angeordnet sind, und für Gradientenindex-Mikrolinsen.

Optique et phonotique - Réseaux de microlentilles - Partie 3: Méthodes d'essai pour les propriétés optiques autres que les aberrations du front d'onde (ISO 14880-3:2006)

L'ISO 14880-3:2006 spécifie les méthodes d'essai des propriétés optiques, autres que les aberrations du front d'onde, des microlentilles dans les réseaux de microlentilles. Elle s'applique aux réseaux de microlentilles avec de très petites lentilles qui composent une ou plusieurs surfaces d'un substrat commun et aux microlentilles à gradient d'indice.

Optika in fotonska tehnologija - Vrste mikroleč - 3. del: Preskusne metode za optične lastnosti, razen odstopanja valovne fronte (ISO 14880-3:2006)

General Information

• Status: Published
• Publication Date: 30-Jun-2006
• ICS: 31.260 - Optoelectronics. Laser equipment
• Technical Committee: VAZ - Healthcare
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Jul-2006
• Due Date: 01-Jul-2006
• Completion Date: 01-Jul-2006
• Ref Project: EN ISO 14880-3:2006 - Optics and phonotics - Microlens arrays - Part 3: Test methods for optical properties other than wavefront aberrations (ISO 14880-3:2006)

Relations

• Revised: oSIST prEN ISO 14880-3:2023 - Optics and photonics - Microlens arrays - Part 3: Test methods for optical properties other than wavefront aberrations (ISO/DIS 14880-3:2023)
• Effective Date: 18-Jan-2023

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 14880-3:2006
01-julij-2006
2SWLNDLQIRWRQVNDWHKQRORJLMD9UVWHPLNUROHþGHO3UHVNXVQHPHWRGH]D
RSWLþQHODVWQRVWLUD]HQRGVWRSDQMDYDORYQHIURQWH,62
Optics and phonotics - Microlens arrays - Part 3: Test methods for optical properties
other than wavefront aberrations (ISO 14880-3:2006)
Optik und Photonik - Mikrolinsenarrays - Teil 3: Prüfverfahren für optische Eigenschaften
außer Wellenfrontaberrationen (ISO 14880-3:2006)
Optique et phonotique - Réseaux de microlentilles - Partie 3: Méthodes d'essai pour les
propriétés optiques autres que les aberrations du front d'onde (ISO 14880-3:2006)
Ta slovenski standard je istoveten z: EN ISO 14880-3:2006
ICS:
31.260 Optoelektronika, laserska Optoelectronics. Laser
oprema equipment
SIST EN ISO 14880-3:2006 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------

EUROPEAN STANDARD
EN ISO 14880-3
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2006
ICS 31.260

English Version
Optics and phonotics - Microlens arrays - Part 3: Test methods
for optical properties other than wavefront aberrations (ISO
14880-3:2006)
Optique et phonotique - Réseaux de microlentilles - Partie Optik und Photonik - Mikrolinsenarrays - Teil 3:
3: Méthodes d'essai pour les propriétés optiques autres Prüfverfahren für optische Eigenschaften außer
que les aberrations du front d'onde (ISO 14880-3:2006) Wellenfrontaberrationen (ISO 14880-3:2006)
This European Standard was approved by CEN on 3 May 2006.
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 Central Secretariat 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 Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,
Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2006 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 14880-3:2006: E
worldwide for CEN national Members.

---------------------- Page: 2 ----------------------

EN ISO 14880-3:2006 (E)





Foreword


This document (EN ISO 14880-3:2006) has been prepared by Technical Committee ISO/TC 172
"Optics and optical instruments" 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 December 2006, and conflicting national
standards shall be withdrawn at the latest by December 2006.

According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary,
Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.


Endorsement notice

The text of ISO 14880-3:2006 has been approved by CEN as EN ISO 14880-3:2006 without any
modifications.

2

---------------------- Page: 3 ----------------------

INTERNATIONAL ISO
STANDARD 14880-3
First edition
2006-06-01

Optics and photonics — Microlens
arrays —
Part 3:
Test methods for optical properties other
than wavefront aberrations
Optique et photonique — Réseaux de microlentilles —
Partie 3: Méthode d'essai pour les propriétés optiques autres que les
aberrations du front d'onde




Reference number
ISO 14880-3:2006(E)
©
ISO 2006

---------------------- Page: 4 ----------------------

ISO 14880-3:2006(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.


©  ISO 2006
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland

ii © ISO 2006 – All rights reserved

---------------------- Page: 5 ----------------------

ISO 14880-3:2006(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
5.3 Preparation . 4
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 (normative) Confocal measurement of effective back or 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 positions of a microlens
array . 13
Bibliography . 14

© ISO 2006 – All rights reserved iii

---------------------- Page: 6 ----------------------

ISO 14880-3:2006(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 14880-3 was prepared by Technical Committee ISO/TC 172, Optics and photonics, Subcommittee SC 9,
Electro-optical systems.
ISO 14880 consists of the following parts, under the general title Optics and photonics — Microlens arrays:
⎯ Part 1: Vocabulary
⎯ Part 2: Test methods for wavefront aberrations
⎯ Part 3: Test methods for optical properties other than wavefront aberrations
⎯ Part 4: Test methods for geometrical properties
iv © ISO 2006 – All rights reserved

---------------------- Page: 7 ----------------------

ISO 14880-3:2006(E)
Introduction
This part of 14880 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 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 the same 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 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 part of 14880 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.
The measurement of 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
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.
© ISO 2006 – All rights reserved v

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INTERNATIONAL STANDARD ISO 14880-3:2006(E)

Optics and photonics — Microlens arrays —
Part 3:
Test methods for optical properties other than wavefront
aberrations
1 Scope
This part of ISO 14880 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 referenced documents are indispensable for the application 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 optical instruments — 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.
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.
© ISO 2006 – All rights reserved 1

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ISO 14880-3:2006(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 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 emitting tip of an 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.
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 focussed 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 charge-coupled device (CCD) camera
Figure 1 — A collimated source and microscope used to measure the effective back
or front focal length of a microlens
2 © ISO 2006 – All rights reserved

---------------------- Page: 10 ----------------------

ISO 14880-3:2006(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 can be used for
monochromatic illumination and higher intensities.
5.2.2.4 Test objects
The distant point source can be approximated using the emitting tip of an 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 undersampling 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 position of best focus. The intensity of the image at the
detector shall be adjusted to maintain a linear response from the detector system.
5.2.2.6 Standard surfaces
A microlens of known focal length at a defined wavelength shall be used as a calibration artefact to verify the
performance of the measurement system.
© ISO 2006 – All rights reserved 3

---------------------- Page: 11 ----------------------

ISO 14880-3:2006(E)
A step height artefact, for example two thin glass plates held together in optical contact to provide a step of
known height, shall be used to verify the performance of the displacement measurement system.
5.3 Preparation
For consistent results the test equipment shall be maintaine
...

EUROPEAN STANDARD
DRAFT
prEN ISO 14880-3
NORME EUROPÉENNE
EUROPÄISCHE NORM
January 2005
ICS
English version
Microlens arrays - Part 3: Test methods for optical properties
other than wavefront aberrations (ISO/DIS 14880-3:2005)
Réseau de microlentilles - Partie 3: Méthodes d'essai pour Mikrolinsenarrays - Teil 3: Prüfverfahren für optische
les propriétés optiques autres que les aberrations du front Eigenschaften außer Wellenfront-Aberrationen (ISO/DIS
d'onde (ISO/DIS 14880-3:2005) 14880-3:2005)
This draft European Standard is submitted to CEN members for parallel enquiry. It has been drawn up by the Technical Committee
CEN/TC 123.
If this draft becomes a European Standard, 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.
This draft European Standard was established by CEN 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 Management Centre has the same
status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2005 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN ISO 14880-3:2005: E
worldwide for CEN national Members.

---------------------- Page: 1 ----------------------
prEN ISO 14880-3:2005 (E)




Foreword


This document (prEN ISO 14880-3:2005) has been prepared by Technical Committee ISO/TC
172 "Optics and optical instruments" in collaboration with Technical Committee CEN/TC 123
"Lasers and laser-related equipment", the secretariat of which is held by DIN.

This document is currently submitted to the parallel Enquiry.


Endorsement notice

The text of ISO 14880-3:2005 has been approved by CEN as prEN ISO 14880-3:2005 without
any modifications.

2

---------------------- Page: 2 ----------------------
DRAFT INTERNATIONAL STANDARD ISO/DIS 14880-3
ISO/TC 172/SC 9 Secretariat: DIN
Voting begins on: Voting terminates on:
2005-01-13 2005-06-13
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION • МЕЖДУНАРОДНАЯ ОРГАНИЗАЦИЯ ПО СТАНДАРТИЗАЦИИ • ORGANISATION INTERNATIONALE DE NORMALISATION
Microlens arrays —
Part 3:
Test methods for optical properties other than wavefront
aberrations
Réseau de microlentilles —
Partie 3: Méthodes d'essai pour les propriétés optiques autres que les aberrations du front d'onde
ICS 31.260

ISO/CEN PARALLEL ENQUIRY
The CEN Secretary-General has advised the ISO Secretary-General that this ISO/DIS covers a subject
of interest to European standardization. In accordance with the ISO-lead mode of collaboration as
defined in the Vienna Agreement, consultation on this ISO/DIS has the same effect for CEN
members as would a CEN enquiry on a draft European Standard. Should this draft be accepted, a
final draft, established on the basis of comments received, will be submitted to a parallel two-month FDIS
vote in ISO and formal vote in CEN.
In accordance with the provisions of Council Resolution 21/1986 this DIS is circulated in the
English language only.
Conformément aux dispositions de la Résolution du Conseil 21/1986, ce DIS est distribué en
version anglaise seulement.
To expedite distribution, this document is circulated as received from the committee secretariat.
ISO Central Secretariat work of editing and text composition will be undertaken at publication
stage.
Pour accélérer la distribution, le présent document est distribué tel qu'il est parvenu du
secrétariat du comité. Le travail de rédaction et de composition de texte sera effectué au
Secrétariat central de l'ISO au stade de publication.
THIS DOCUMENT IS A DRAFT CIRCULATED FOR COMMENT AND APPROVAL. IT IS THEREFORE SUBJECT TO CHANGE AND MAY NOT BE
REFERRED TO AS AN INTERNATIONAL STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS BEING ACCEPTABLE FOR INDUSTRIAL, TECHNOLOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN NATIONAL REGULATIONS.
© International Organization for Standardization, 2005

---------------------- Page: 3 ----------------------
ISO/DIS 14880-3
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall
not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the
unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
Copyright notice
This ISO document is a Draft International Standard and is copyright-protected by ISO. Except as permitted
under the applicable laws of the user's country, neither this ISO draft nor any extract from it may be
reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, photocopying,
recording or otherwise, without prior written permission being secured.
Requests for permission to reproduce should be addressed to either ISO at the address below or ISO's
member body in the country of the requester.
ISO copyright office
Case postale 56  CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Reproduction may be subject to royalty payments or a licensing agreement.
Violators may be prosecuted.
©
ii ISO 2005 – All rights reserved

---------------------- Page: 4 ----------------------
ISO/DIS 14880-3
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. 2
5.1 Principle. 2
5.2 Measurement arrangement and test equipment. 2
5.2.1 General. 2
5.2.2 Test system . 3
5.3 Preparation . 4
6 Procedure . 4
6.1 General. 4
6.2 Measurement of effective back or front focal length . 4
6.3 Measurement of chromatic aberration . 5
7 Results and uncertainties . 5
8 Test report . 6
Annex A (informative) Measurements with wavefront measuring systems. 8
A.1 Interferometer measurement principle. 8
A.2 Measurement arrangement and test equipment. 8
A.3 Measurement of effective back or front focal length . 9
Annex B (normative) Confocal measurement of effective back or front focal length of lens array. 10
B.1 Measurement principle. 10
B.2 Measurement system for microlens array. 11
Annex C (informative) Coupling efficiency, imaging quality . 12
C.1 Coupling efficiency. 12
C.2 Imaging Quality. 12
Bibliography . 13
© ISO 2004 – All rights reserved iii
DRAFT 2005

---------------------- Page: 5 ----------------------
ISO/DIS 14880-3
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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 14880-3 was prepared by Technical Committee ISO/TC 172, Optics and photonics, Subcommittee SC 9,
Electro-optical systems.
ISO 14880 consists of the following parts, under the general title Microlens arrays:
 Part 1: Vocabulary
 Part 2: Test methods for wavefront aberrations
 Part 3: Test methods for optical properties other than wavefront aberrations
 Part 4: Test methods for geometrical properties
iv © ISO 2004 – All rights reserved
DRAFT 2005

---------------------- Page: 6 ----------------------
ISO/DIS 14880-3
Introduction
This standard 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 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 the same 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 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.
Part 3 contributes to the purpose of ISO 14880 which is to improve the compatibility and interchangeability of
lens arrays from different suppliers and to enhance development of the technology using microlens arrays.
The measurement of focal length is described in the main body 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
Annex B.
Coupling efficiency and imaging quality are discussed in Annex C.
© ISO 2004 – All rights reserved v
DRAFT 2005

---------------------- Page: 7 ----------------------
DRAFT INTERNATIONAL STANDARD ISO/DIS 14880-3
Microlens arrays — Part 3: Test methods for optical properties
other than wavefront aberrations
1 Scope
This standard specifies methods for testing optical properties, other than wavefront aberrations, of
microlenses in microlens arrays. It applies 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 referenced documents are indispensable for the application 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, Microlens array — Part 1: Vocabulary
ISO 14880-2, Microlens arrays — Test methods for wavefront aberrations
ISO 10110-5, Optics and optical instruments — Preparation of drawings for optical elements and systems —
Part 5 : Surface form tolerances
1)
ISO/TR 14999-1 , Optics and photonics — Interferometric measurement of optical elements and optical
systems — Part 1: Definitions and fundamental relationships
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 14880-1and the following apply.
Table 1 — Symbols and units of measure
Symbol Unit Term
wavelength
λµ m, nm
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 according to ISO 10110-5.

1) to be published
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ISO/DIS 14880-3
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.
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 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 emitting tip of an optical fibre or an illuminated test graticule. Tests may be
performed with white light or monochromatic illumination.
The second technique uses interferometry to generate patterns that indicate the location of 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, Twyman-Green, lateral shearing interferometer or a Shack-Hartmann device. 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.
The body of this document concentrates on the microscope technique while an interferometric technique is
described in Annex A.
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ISO/DIS 14880-3
Key
1 distantpoint source
2 substrate and microlens producing focussed 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 CCD camera
Figure 1 — A collimated source and microscope used to measure the effective back or front focal
length of a microlens
5.2.2 Test system
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).
5.2.2.1 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 must
allow the distant point or test graticule to
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