IEC 61988-2-6:2015

IEC 61988-2-6 ®
Edition 1.0 2015-03
INTERNATIONAL
STANDARD
colour
inside
Plasma display panels –
Part 2-6: Measuring methods – APL dependent gamma and colour
characteristics
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 more than 30 000 terms and
Technical Specifications, Technical Reports and other definitions in English and French, with equivalent terms in 15
documents. Available for PC, Mac OS, Android Tablets and additional languages. Also known as the International
iPad. Electrotechnical 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 More than 60 000 electrotechnical terminology entries in
variety of criteria (reference number, text, technical English and French extracted from the Terms and Definitions
committee,…). It also gives information on projects, replaced clause of IEC publications issued since 2002. Some entries
and withdrawn publications. have been 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 61988-2-6 ®
Edition 1.0 2015-03
INTERNATIONAL
STANDARD
colour
inside
Plasma display panels –
Part 2-6: Measuring methods – APL dependent gamma and colour

characteristics
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 31.260 ISBN 978-2-8322-2399-4

– 2 – IEC 61988-2-6:2015 © IEC 2015
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references. 6
3 Terms, definitions and abbreviations . 6
3.1 Terms and definitions . 6
3.2 Abbreviations . 7
4 Measurement equipment . 7
4.1 Video signal generator . 7
4.2 Non-contact LMD (light measurement device) . 7
4.3 Contact LMD . 7
5 Measurement conditions . 7
5.1 General . 7
5.2 Setup conditions . 7
5.3 Measuring layout . 8
5.4 Input signal level and picture level . 9
6 Measuring methods of tone characteristics . 10
6.1 Purpose . 10
6.2 Input signals . 11
6.2.1 General . 11
6.2.2 11-step grey bar with fixed APL . 11
6.2.3 Single grey window with fixed APL . 12
6.2.4 11-step RGB bar and single colour window with fixed APL . 13
6.3 Measuring procedure . 14
6.4 Expression of results . 15
6.4.1 Measurement report . 15
6.4.2 Gamma calculation . 16
7 Measuring methods of colour gamut by APL . 19
7.1 Purpose . 19
7.2 Primary and secondary colour patterns by APL . 19
7.3 Measuring procedure . 19
7.4 Evaluation of colour accuracy . 20
7.5 Evaluation of colour gamut . 20
7.6 Expression of results . 21
Annex A (informative) Use of ITU-R Rec. BT.709-5 signal . 25
Bibliography . 26

Figure 1 − Measuring layout for non-contact measurement . 8
Figure 2 − Measuring layout for contact measurement . 9
Figure 3 – Input signals and signal processing in a PDP module . 10
Figure 4 – An example of an 11-step grey-bar pattern . 12
Figure 5 – Example of 4 % window pattern for measuring the tone characteristics . 12
Figure 6 − RGB bar and single window pattern . 13
Figure 7 − An example of results of gamma characteristics for each APL . 15
Figure 8 − Example plots for calculated gamma values by APL . 17

Figure 9 − Example plots for CCT characteristics by APL . 18
Figure 10 − Example plots for ∆u’v’ characteristics by APL . 18
Figure 11 − 4 % C, M, and Y single window pattern . 19
Figure 12 − ITU-R Rec. BT.709-5 standard coordinates of primary and secondary
colours . 20
Figure 13 – Example showing a measured primary, a reference, and an overlapped
gamut area . 21
Figure 14 − The measured colour gamut plots by APL . 24

Table 1 − An example of a tone measurement report . 15
Table 2 − Example of gamma reporting form (for each APL ) . 17
Table 3 – An example of gamut areas for evaluation of colour gamut . 21
Table 4 − An example of primary and secondary colour measurement report . 22
Table A.1 – Digital data and signal level in ITU-R Rec. BT.709-5 . 25

– 4 – IEC 61988-2-6:2015 © IEC 2015
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PLASMA DISPLAY PANELS –
Part 2-6: Measuring methods –
APL dependent gamma and colour characteristics

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61988-2-6 has been prepared by IEC technical committee 110:
Electronic display devices.
The text of this standard is based on the following documents:
FDIS Report on voting
110/636/FDIS 110/652/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

A list of all the parts in the IEC 61988 series, under the general title Plasma display panels,
can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
– 6 – IEC 61988-2-6:2015 © IEC 2015
PLASMA DISPLAY PANELS –
Part 2-6: Measuring methods –
APL dependent gamma and colour characteristics

1 Scope
This part of IEC 61988 defines the measuring methods for gamma and colour gamut
characteristics as a function of the APL for a PDP module (plasma display module). Generally,
the luminance level of a PDP module is dependent on the APL (average picture level) of input
images. Varying the input levels causes a change of the chromaticity of RGB primary colours.
This standard also defines the measuring methods of tone characteristics and chromaticity
characteristics with varying APLs. This standard is based on the assumption that the inverse-
gamma circuit is inside the module.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60068-1, Environmental testing – Part 1: General and guidance
IEC 60107-1, Methods of measurement on receivers for television broadcast
transmissions − Part 1: General considerations − Measurements at radio and video
frequencies
IEC 61966-5, Multimedia system and equipment – Colour measurement and management –
Part 5: Equipment using plasma display panels
IEC 61988-1, Plasma display panels – Part 1: Terminology and letter symbols
IEC 61988-2-1, Plasma display panels − Part 2-1: Measuring methods − Optical and
optoelectrical
CIE 15:2004, Colorimetry
ITU-R Rec. BT.709-5, Parameter values for the HDTV standards for production and
international programme exchange
3 Terms, definitions and abbreviations
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60068-1,
IEC 60107-1 and IEC 61988-1, as well as the following apply.
3.1.1
tone
characteristics of the relationship between input signal level and output luminance

3.1.2
colour difference
difference between two colour stimuli, defined as the Euclidean distance between the points
representing them in a specific colour space such as CIE 1976 u’v’ colour space.
3.1.3
colour gamut area
two-dimensional maximum area of reproducible colours expressed in the CIE 1976 colour
space defined in CIE 15
3.2 Abbreviations
For the purposes of this document, the following abbreviations apply.
APL Average picture level
CCT Correlated colour temperature
LMD Light measuring device
PDP Plasma display
4 Measurement equipment
4.1 Video signal generator
An analogue video signal generator or a digital video signal generator is used. The signal
characteristics shall match with the measured PDP module. Input signal, in this document,
means a pre-gamma signal and APL means a post-gamma APL.
4.2 Non-contact LMD (light measurement device)
When using a non-contact LMD, the non-contact LMD incorporates a spectroradiometer or a
non-contact colorimeter as shown in Figure 1. The detail conditions are defined in
IEC 61988-2-1, where a non-contact LMD is described as an LMD.
NOTE: See IEC 61966-5.
4.3 Contact LMD
When using a contact LMD, the measurement probe shall be placed perpendicular to the
display surface and include at least 500 pixels in the measurement aperture. It shall be
confirmed that the results measured by the contact LMD are the same as the results
measured by the non-contact LMD.
5 Measurement conditions
5.1 General
The following standard setup conditions shall be used. Each condition shall be noted on the
relevant specification whenever any different conditions other than the standard setup
conditions are applied. (See the measuring conditions in IEC 61966-5 and IEC 61988-2-1.)
5.2 Setup conditions
All measurements shall be carried out in a dark room. Illuminance shall be less than 1 lx
anywhere on the screen of the PDP module. When this illuminance significantly affects the
measurement of the black level, the background subtraction method shall be used. When a

– 8 – IEC 61988-2-6:2015 © IEC 2015
different illuminance or the background subtraction method is used, this shall be noted on the
report.
The warm-up time shall be longer than 30 minutes with a signal input set at 15 % grey level
on full screen without gamma correction, unless other specified measuring methods are used.
When different warm-up conditions are used, they shall be noted on the report.
For the measurement of tone characteristics, the conditions of contrast and colour
enhancement functions to preserve the tone characteristics of the panel itself shall be applied
and noted on the report. The image sticking preventing function (for a still image) shall be
turned off, or some procedures in which the function is kept inactive can be applied.
5.3 Measuring layout
The measuring equipment shall be set as shown in Figure 1 for a non-contact LMD and in
Figure 2 for a contact LMD. The optical axis of the non-contact LMD should be normal to the
centre of the display surface. It is recommended that the measuring distance ℓ of LMD is
2,5V, where V is the effective screen height of the display.
PDP module
V
LMD
Pattern
ℓ
generator
Measuring distance
Control PC
(if used)
IEC
Figure 1 − Measuring layout for non-contact measurement
The measuring layout for a contact LMD is shown in Figure 2. A measurement probe shall be
set to the surface of the display.

PDP module
(Measurement probe)
LMD
Pattern
Control body
generator
Control PC
(if used)
IEC
Figure 2 − Measuring layout for contact measurement
5.4 Input signal level and picture level
For the measurement, analogue video signals or digital video signals are used as input
signals. The input signal level is the level of the analogue video signal and is indicated in
percent (0 % to 100 %, I to I respectively), while the conventional digital input data is
0 % 100 %
N
the level of the digital input video signal having a value from 0 to 2 -1, where N is the number
of the bits for the digital video signal. When N is 8, 256 grey steps are used. Basically these
input video signals are pre-gamma signals having an applied gamma correction of 2,2. The
th
output luminance level is related to 2,2 power of the input signal level. The term picture level,
which relates to luminance, is used for the output luminance level of the post-gamma signal.
Figure 3 shows these relationships.
NOTE In the ITU-R Rec. BT.709-5 8-bit digital video signal, the digital data is compressed to 16 to 235 from 0 to
255. The input signal at level 0 % is the digital data of 16 and the input signal at level 100 % is the digital data of
235. The input digital data is modified to this relationship as shown in Annex A. In this document the procedure of
the conventional digital signal is mainly mentioned.

– 10 – IEC 61988-2-6:2015 © IEC 2015
Digital video Analogue
N a
video signal
signal
I = D/(2 -1) x 100 (%)
Input signal
Digital data
(D) level
(I)
Pre-gamma signal
Reverse gamma conversion
th
(2,2 power of I)
Post-gamma signal
Output
luminance
signal
APL (average picture level):
the average of an image on
Picture
the total screen
level
2,2
(I )
Automatic brightness control (ABL), etc.
Panel
driving
signal
Panel characteristics
Output
luminance
(L)
IEC
a For the use of the ITU-R Rec. BT.709-5 8-bit digital signal, the relationship between the input signal level and
the digital data is as follows:
I = (D-16)/(235-16) × 100 (%)
Figure 3 – Input signals and signal processing in a PDP module
6 Measuring methods of tone characteristics
6.1 Purpose
The purpose of this method is to measure the tone characteristics of a PDP as a function of
the APL. The following items are then measured:
a) APL dependent gamma characteristics,
b) signal level and APL dependent CCT (correlated colour temperature), and
c) signal level and APL dependent chromaticity coordinates (u’v’).
NOTE u' and v' are CIE 1976 UCS
...