IEC 62715-5-1:2017

IEC 62715-5-1 ®
Edition 1.0 2017-05
INTERNATIONAL
STANDARD
colour
inside
Flexible display devices –
Part 5-1: Measuring methods of optical performance
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 IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

IEC Central Office Tel.: +41 22 919 02 11
3, rue de Varembé Fax: +41 22 919 03 00
CH-1211 Geneva 20 info@iec.ch
Switzerland www.iec.ch
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.

IEC Catalogue - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
The stand-alone application for consulting the entire The world's leading online dictionary of electronic and
bibliographical information on IEC International Standards, electrical terms containing 20 000 terms and definitions in
Technical Specifications, Technical Reports and other English and French, with equivalent terms in 16 additional
documents. Available for PC, Mac OS, Android Tablets and languages. Also known as the International Electrotechnical
iPad. Vocabulary (IEV) online.

IEC publications search - www.iec.ch/searchpub IEC Glossary - std.iec.ch/glossary
The advanced search enables to find IEC publications by a 65 000 electrotechnical terminology entries in English and
variety of criteria (reference number, text, technical French extracted from the Terms and Definitions clause of
committee,…). It also gives information on projects, replaced IEC publications issued since 2002. Some entries have been
and withdrawn publications. collected from earlier publications of IEC TC 37, 77, 86 and

CISPR.
IEC Just Published - webstore.iec.ch/justpublished

Stay up to date on all new IEC publications. Just Published IEC Customer Service Centre - webstore.iec.ch/csc
details all new publications released. Available online and If you wish to give us your feedback on this publication or
also once a month by email. need further assistance, please contact the Customer Service
Centre: csc@iec.ch.
IEC 62715-5-1 ®
Edition 1.0 2017-05
INTERNATIONAL
STANDARD
colour
inside
Flexible display devices –
Part 5-1: Measuring methods of optical performance

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 31.120 ISBN 978-2-8322-4354-1

– 2 – IEC 62715-5-1:2017  IEC 2017
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms, definitions and abbreviated terms . 8
3.1 Terms and definitions . 8
3.2 Abbreviated terms . 9
4 Structure of measuring equipment . 9
4.1 Measuring configuration – Display mounting . 9
4.1.1 General . 9
4.1.2 Display mounting for uniformity measurements . 10
4.1.3 Display mounting for viewing direction measurements . 10
4.2 Light measuring device . 11
4.3 Light source configurations . 13
4.3.1 General . 13
4.3.2 Uniform hemispherical diffuse illumination . 13
4.3.3 Directed source illumination . 14
5 Standard measuring conditions . 15
5.1 Standard measuring environmental conditions . 15
5.2 Standard lighting conditions . 15
5.2.1 Dark room conditions . 15
5.2.2 Standard ambient illumination spectra . 15
5.2.3 Standard illumination geometries . 17
5.2.4 Diffuse reflectance standard . 17
5.3 Standard setup conditions . 17
5.3.1 Adjustment of display modules . 17
5.3.2 Starting conditions of measurements . 17
5.3.3 Conditions of measuring equipment . 18
5.4 Standard locations of measurement field. 18
6 Optical measuring methods in dark room conditions . 18
6.1 Luminance and its uniformity. 18
6.1.1 General . 18
6.1.2 Measuring equipment . 19
6.1.3 Screen centre luminance measuring method . 19
6.1.4 Luminance uniformity measuring method . 19
6.1.5 Luminance uniformity definition and evaluation . 20
6.2 Contrast ratio . 20
6.2.1 General . 20
6.2.2 Measuring equipment . 20
6.2.3 Measuring method . 20
6.2.4 Definition and evaluation . 20
6.3 Chromaticity, colour uniformity, and colour gamut area . 21
6.3.1 General . 21
6.3.2 Measuring equipment . 21
6.3.3 Screen centre chromaticity measuring method . 21
6.3.4 Screen centre colour gamut and colour gamut area measuring method . 22

6.3.5 Colour uniformity measuring method . 24
6.4 Peak white field correlated colour temperature . 25
6.4.1 General . 25
6.4.2 Measuring equipment . 25
6.4.3 Measuring method . 25
6.5 Viewing direction dependence . 25
6.5.1 General . 25
6.5.2 Measuring equipment . 25
6.5.3 Measuring method . 26
6.5.4 Definition and evaluation . 27
6.6 Cross-talk with display in bent state . 28
6.6.1 General . 28
6.6.2 Measuring equipment . 28
6.6.3 Measuring method . 29
7 Optical measuring method under ambient illumination . 31
7.1 Reflection measurements . 31
7.1.1 General . 31
7.1.2 Measuring conditions . 32
7.2 Ambient contrast ratio . 35
7.2.1 General . 35
7.2.2 Measuring conditions . 36
7.2.3 Measuring method . 36
7.3 Ambient display colour . 36
7.3.1 General . 36
7.3.2 Measuring conditions . 37
7.3.3 Measuring method . 37
7.4 Ambient colour gamut volume . 38
7.4.1 General . 38
7.4.2 Measuring conditions . 38
7.4.3 Measuring method . 38
7.4.4 Reporting . 40
Annex A (informative) Calculation method of ambient colour gamut volume . 42
A.1 Purpose . 42
A.2 Procedure for calculating the colour gamut volume . 42
A.3 Surface subdivision method for CIELAB gamut volume calculation . 44
A.3.1 Purpose . 44
A.3.2 Assumptions . 44
A.3.3 Algorithm . 44
A.3.4 Software example execution . 45
Bibliography . 49

Figure 1 – Example of the coordinate system used for a convex display of a constant
radius of curvature about the y-axis . 10
Figure 2 – Top view example of how a convex display can be rotated within the
measurement field . 10
Figure 3 – Top view example of display mount that rotates in the x-z plane for viewing
direction measurements . 11
Figure 4 – Optical characteristics of a spot photometer, colorimeter, or
spectroradiometer . 12

– 4 – IEC 62715-5-1:2017  IEC 2017
Figure 5 – Example of the relationship between measurement field diameter and
inclinations angles . 13
Figure 6 –
...