EN 62595-1-2:2012

SLOVENSKI STANDARD
01-maj-2012
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LCD backlight unit - Part 1-2: Terminology and letter symbols
LCD-Hinterleuchtungseinheiten - Teil 1-2: Begriffsbestimmungen und Kurzzeichen
Ecran LCD à rétro-éclairage - Partie 1-2 : Terminologie et symboles littéraux
Ta slovenski standard je istoveten z: EN 62595-1-2:2012
ICS:
01.040.31 Elektronika (Slovarji) Electronics (Vocabularies)
01.075 Simboli za znake Character symbols
31.120 Elektronske prikazovalne Electronic display devices
naprave
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 62595-1-2
NORME EUROPÉENNE
February 2012
EUROPÄISCHE NORM
ICS 31.120; 31.260
English version
LCD backlight unit -
Part 1-2: Terminology and letter symbols
(IEC 62595-1-2:2011)
Ecran LCD à rétro-éclairage -  LCD-Hinterleuchtungseinheiten -
Partie 1-2 : Terminologie et symboles Teil 1-2: Begriffsbestimmungen und
littéraux Kurzzeichen
(CEI 62595-1-2:2011) (IEC 62595-1-2:2011)

This European Standard was approved by CENELEC on 2012-01-18. CENELEC 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 CENELEC 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 CENELEC member into its own language and notified
to the CEN-CENELEC Management Centre has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus,
the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia,
Spain, Sweden, Switzerland, Turkey and the United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Management Centre: Avenue Marnix 17, B - 1000 Brussels

© 2012 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 62595-1-2:2012 E
Foreword
The text of document 110/275/CDV, future edition 1 of IEC 62595-1-2, prepared by IEC TC 110, "Flat
panel display devices" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:
(dop) 2012-10-18
• latest date by which the document has
to be implemented at national level by
publication of an identical national
standard or by endorsement
(dow) 2015-01-18
• latest date by which the national
standards conflicting with the
document have to be withdrawn
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such patent
rights.
Endorsement notice
The text of the International Standard IEC 62595-1-2:2011 was approved by CENELEC as a European
Standard without any modification.

- 3 - EN 62595-1-2:2012
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

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.

NOTE  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.
Publication Year Title EN/HD Year

IEC 60050 Series International electrotechnical vocabulary - -

IEC 62595-1-2 ®
Edition 1.0 2011-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
LCD backlight unit –
Part 1-2: Terminology and letter symbols

Écran LCD à rétro-éclairage –
Partie 1-2: Terminologie et symboles littéraux

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX T
ICS 31.120; 31.260 ISBN 978-2-88912-837-2

– 2 – 62595-1-2  IEC:2011
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
3.1 Classification of terms . 5
3.2 Fundamental terms. 5
3.3 Terms related to passive optical components . 9
3.4 Terms related to light sources . 12
3.4.1 Light Emitting Diode (LED) . 12
3.4.2 LED light bar . 13
3.5 Terms related to light source drivers . 13
3.6 Terms related to frontlight unit . 14
3.7 Terms related to performances and specifications . 15
3.8 Terms related to backlight dimming . 17
4 Letter symbols (quantity symbols / unit symbols) . 18
Annex A (informative) Supplementary figures . 19

Figure A.1 – Backlighting concept for transmissive and transflective LCD . 19
Figure A.2 – Examples of edge-lit backlight units . 19
Figure A.3 – Example of direct-lit backlight units. . 20
Figure A.4 – Examples of spectral power distributions (pseudo-white and RGB LEDs) . 20
Figure A.5 – Polar coordinates for evaluation of the luminance angular distribution . 20
Figure A.6 – Luminance uniformity on a backlight unit . 21
Figure A.7 – Incoherent point spread function for evaluation of a segment in a block-
wise dynamic backlight unit. White and black segments show the on and off conditions,
applied to all segments . 21
Figure A.8 – Incoherent point spread function of a block in a block-wise backlight unit,
with different distributions . 22
Figure A.9 – Angular luminance variation on a backlight unit . 23
Figure A.10 – Checkerboard pattern for evaluation of the uniformity between the

incoherent point spreading functions of the segments of dynamic backlight unit . 23

62595-1-2  IEC:2011 － 3 －
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
LCD BACKLIGHT UNIT –
Part 1-2: Terminology and letter symbols

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 62595-1-2 has been prepared by IEC technical committee 110:
Flat panel display devices.
The text of this standard is based on the following documents:
CDV Report on voting
110/275/CDV 110/323/RVC
Full information on the voting for the approval on 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 62595 series, under the general title LCD Backlight Unit, can
be found on the IEC website.
– 4 – 62595-1-2  IEC:2011
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.
62595-1-2  IEC:2011 － 5 －
LCD BACKLIGHT UNIT –
Part 1-2: Terminology and letter symbols

1 Scope
This part of IEC 62595 gives preferred terms, their definitions and symbols for backlight unit
(BLU) and related display panel lighting systems including frontlight; with the object of using
the same terminology when publications are prepared in different countries.
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 60050 (all parts), International Electrotechnical Vocabulary (available at
)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60050-845:1987
and the following apply.
3.1 Classification of terms
Terms for backlight units (BLUs) are classified as follows:
a) fundamental terms;
b) terms related to passive optical components;
c) terms related to light sources ;
d) terms related to light source drivers;
e) terms related to frontlight unit;
f) terms related to performances and specifications ;
g) terms related to backlight dimming.
The following definitions are applied for international standardization of the backlight units.
3.2 Fundamental terms
3.2.1
backlight unit
BLU
illumination unit (arbitra
...