IEC 62595-2-5:2021

IEC 62595-2-5 ®
Edition 1.0 2021-05
INTERNATIONAL
STANDARD
colour
inside
Display lighting unit –
Part 2-5: Measurement method for optical quantities of non-planar light sources
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 info@iec.ch
CH-1211 Geneva 20 www.iec.ch
Switzerland
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 corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform IEC online collection - oc.iec.ch
The advanced search enables to find IEC publications by a Discover our powerful search engine and read freely all the
variety of criteria (reference number, text, technical publications previews. With a subscription you will always
committee, …). It also gives information on projects, replaced have access to up to date content tailored to your needs.
and withdrawn publications.
Electropedia - www.electropedia.org
IEC Just Published - webstore.iec.ch/justpublished
The world's leading online dictionary on electrotechnology,
Stay up to date on all new IEC publications. Just Published
containing more than 22 000 terminological entries in English
details all new publications released. Available online and
and French, with equivalent terms in 18 additional languages.
once a month by email.
Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Customer Service Centre - webstore.iec.ch/csc

If you wish to give us your feedback on this publication or
need further assistance, please contact the Customer Service
Centre: sales@iec.ch.
IEC 62595-2-5 ®
Edition 1.0 2021-05
INTERNATIONAL
STANDARD
colour
inside
Display lighting unit –
Part 2-5: Measurement method for optical quantities of non-planar light sources

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 31.120; 31.260 ISBN 978-2-8322-9771-1

– 2 – IEC 62595-2-5:2021 © IEC 2021
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms, definitions, abbreviated terms and letter symbols . 9
3.1 Terms and definitions. 9
3.2 Abbreviated terms . 9
3.3 Letter symbols (quantity symbols/unit symbols). 10
4 Measurement devices . 11
4.1 General . 11
4.2 Spot-type light measuring device . 11
4.3 Spectroradiometer (spectral radiance-meter) . 12
4.4 Electrical measurement devices . 12
4.4.1 Current meter . 12
4.4.2 Voltage meter . 13
4.5 Luminous flux measurement devices . 13
4.5.1 General . 13
4.5.2 Luminous flux . 13
4.5.3 Sample stage . 15
5 General measuring conditions . 15
5.1 Standard conditions . 15
5.2 Darkroom conditions . 16
5.3 Measurement setup . 16
5.4 Setting the electrical characteristics of measurement devices . 16
5.4.1 Conditions . 16
5.4.2 Current . 16
5.4.3 Voltage . 16
5.4.4 Power . 16
5.4.5 Warm-up time . 17
6 Optical measurement methods . 17
6.1 General . 17
6.2 Conditions . 17
6.3 Perceptual visual quality . 17
6.3.1 General . 17
6.3.2 Procedures . 17
6.4 Lateral and directional scanning configuration . 18
6.4.1 General . 18
6.4.2 Lateral scanning configuration . 18
6.4.3 Directional scanning configuration . 20
6.5 Depth-of-field and depth-of-focus in measurement . 22
6.5.1 General . 22
6.5.2 Front and rear depth-of-field (DoF) . 22
6.5.3 Front and rear depth-of-focus (dof) . 23
6.6 Measurement procedures. 23
6.6.1 General . 23
6.6.2 Cylindrical LS mounting for lateral measurements . 23

6.6.3 Lateral luminance . 24
6.6.4 Lateral luminance uniformity . 24
6.6.5 Lateral chromaticity and chromaticity variation . 25
6.6.6 Directional luminance . 25
6.6.7 Directional luminance variations . 26
6.6.8 Directional chromaticity and chromaticity variation . 26
6.6.9 Luminous flux . 27
7 Precautions . 30
7.1 Remarks . 30
7.2 Further remarks . 31
7.2.1 General . 31
7.2.2 Report . 31
Annex A (informative) Measurement field on the curved light source . 32
A.1 General . 32
A.2 NPLS curvature and measurement field . 32
A.3 MFs on planar, convex and concave cylindrical LSs . 33
Annex B (informative) Planar light source measurement . 35
B.1 General . 35
B.2 Luminance meter and measurement field . 35
Annex C (informative) Contours of light measurement fields on plane, cylindrical
convex, and concave light sources . 36
C.1 General . 36
C.2 MF contour on a non-tilt and tilt planar DUT . 36
C.3 Projection of an MF contour on the outer surface of a cylindrical DUT . 37
Annex D (informative) LMD aperture and inclination angle on a cylindrical light source . 41
D.1 General . 41
D.2 Inclination angle. 41
D.3 Inclination angle variation . 42
D.4 Depth-of-field . 43
D.5 Measurement field size on the cylindrical light source . 45
Bibliography . 50

Figure 1 – Cartesian and spherical coordinate systems for NPLS measurement . 11
Figure 2 – Example of LMD with the observation area surrounding the measurement field . 12
Figure 3 – Current and voltage measurements using an ammeter between points C and

D and a voltage meter between points A and B . 13
Figure 4 – Geometry of 4π-sphere measurement . 14
Figure 5 – Measuring points on convex and concave DUTs based on the setups of
Figure 4 . 15
Figure 6 – Example of a mirror type goniometric system . 15
Figure 7 – Planar LS and cylindrical LS (NPLS) in lateral scanning measurement
arrangements . 19
Figure 8 – Planar LS and cylindrical LS (NPLS) in a directional scanning arrangement . 21
Figure 9 – Pictorial illustration of depth-of-field, depth-of-focus and circle of confusion
for an LMD . 22
Figure 10 – Rear depth-of-field in the measurement setup of a cylindrical light source . 23
Figure A.1 – Schematic diagram of the optical characteristics measurement of planar,
convex and concave cylindrical light source . 32

– 4 – IEC 62595-2-5:2021 © IEC 2021
Figure C.1 – Geometry of intersections of a cone and a plane in non-tilt and tilt
conditions . 36
Figure C.2 – Expanded plane of a cone and intersection lines with tilt and non-tilt

planes (see Figure C.1) . 37
Figure C.3 – Simulated intersections of three planar light sources with a cone
(measurement field
...