SIST EN 62595-1-2:2012

SLOVENSKI STANDARD
01-maj-2012
=DVORQ/&']RVYHWOLWYLMRR]DGMDGHO7HUPLQRORJLMDLQþUNRYQLVLPEROL
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 (arbitrary shape) with unique optical characteristics that is set at the rear of a
transmissive or transflective display panel for the purpose of image recognition on the panel
Note 1 to entry: For an example, see Figure A.1.
———————
Identical to CIE 17.4.
– 6 – 62595-1-2  IEC:2011
3.2.2
edge-lit backlight unit
side-lit backlight unit
edge-light backlight unit
side-light backlight unit
backlight unit in which an optically transparent media (light-guide plate) is used in proximity
with the light source for introducing the light from the side surface of the media
Note 1 to entry: For an example, see Figure A.2.
3.2.3
direct-lit backlight unit
direct-view backlight unit
backlight unit in which a light chamber is used in combination with light sources that are
mounted inside the chamber to illuminate a transmissive LCD panel mounted on the chamber
for modulating spatially the displayed two-dimensional information on the panel for the
purpose of image recognition
Note 1 to entry: For an example, see Figure A.3.
3.2.4
side-driven direct-lit backlight unit
backlight unit in which a light chamber is used in combination with light sources that are
mounted on the inner sides of the chamber to illuminate a panel mounted on the chamber for
modulating spatially the displayed two-dimensional information on the panel for the purpose of
image recognition
3.2.5
static backlight unit
single or integrated flat illumination system that operates with direct or alternative current and
possesses a unique optical characteristic
3.2.6
dynamic backlight unit
single or integrated illumination units that possess a unique electro-optical and spatial
characteristics which change with the local picture contents of the display panel
3.2.7
blinking backlight unit
backlight unit that is intentionally, usually regularly or periodically, switched on and off for
synchronically illuminating a display panel
3.2.8
scanning backlight unit
backlight unit that is divided spatially into few line blocks and regularly or periodically
switched on and off block by block for synchronous illumination of the display panel
3.2.9
spatio-temporal backlight unit
backlight unit that is divided spatially into few horizontal blocks and regularly or periodically
switched on and off from top to bottom under a time chart for illuminating or flashing red,
green, or blue light in synchronization with a field-sequential colour display
3.2.10
field alternative backlight unit
backlight unit that includes a single light-guide plate (LGP) with distinctive upper and lower
light sources or a plate that is spatially divided into two upper and lower plates for cooperation
with a display panel for illuminating or flashing alternatively the panel with respect to
displayed half image by the upper or lower part of the panel

62595-1-2  IEC:2011 － 7 －
3.2.11
single-side emission backlight unit
backlight unit that emits light from a single side (front or rear) for illuminating a single display
panel
3.2.12
double-side emission backlight unit
backlight unit that emits light from both front and rear for illuminating two display panels
3.2.13
segmented backlight unit
backlight unit that is block-wised or segmented two-dimensionally to be synchronized with a
display panel for illuminating individually each block or segment of the display
3.2.14
quasi-monochromatic backlight unit
backlight unit that uses only quasi-monochromatic light source for illuminating transmissive
passive display panel
3.2.15
multi-colour backlight unit
backlight unit that consists of few primaries or quasi-monochromatic light sources for
illuminating a display that is used for wide colour gamut display of printer, professional design
monitor or field alternative wide colour gamut display panel
3.2.16
mobility enhanced backlight unit
backlight unit that employs light materials and few optical components for the sake of
enhancing lightness for mobility
3.2.17
corner driven backlight unit
edge-lit backlight unit in which the light is driven from the corner of a rectangular light-guide
plate using single or few light sources
3.2.18
stack backlight unit
backlight unit in which more than a single light control media or light-guide plate is used in
stack form in the structure for light controlling
3.2.19
colour reproduction backlight unit
backlight unit that uses primaries for the sake of colour production on a display panel
3.2.20
RG-white backlight unit
backlight unit that uses RG-white LEDs as light sources
3.2.21
RGW backlight unit
backlight unit that uses distinct red, green and pseudo-white LEDs as light sources
3.2.22
three primaries (R,G,B) backlight unit
backlight unit that uses three primary colours of red, green, and blue quasi-monochromatic
LEDs as light sources
– 8 – 62595-1-2  IEC:2011
3.2.23
six primaries (R ,G ,B ,R ,G ,B ) backlight unit
1 1 1 2 2 2
backlight unit employing two groups of red, green and blue light sources for illuminating a
display panel which is used for reproduction of colours of photographs
3.2.24
single-flash backlight unit
backlight unit that flashes periodically and is synchronized with the display panel for the
purpose of inserting black or grey frame in order to enhance the moving image quality on the
display
3.2.25
multi-flash backlight unit
spatially and linearly segmented backlight unit for scanning or field-sequential colour display
that flashes periodically and is synchronized with the display for the purpose of inserting
colour fields, black or grey fields in order to enhance the image quality on the display or
spatially mix the colours for displaying coloured images
3.2.26
multi-primary colours backlight unit
backlight unit that employs multiple LED or laser light sources which have different peak
wavelengths
3.2.27
tandem backlight unit
backlight unit that is an integration of multiple distinct and overlapped edge-lit backlight units
3.2.28
spectral power distribution
power per unit area per unit wavelength of a backlight unit, or a bound of light spectral
distribution with a power per wavelength, S(λ), that emerges from a unit area on the backlight
and is measured using a spectrometer or an optical spectrum analyser
Note 1 to entry: For an example, see Figure A.4.
3.2.29
chromaticity
chromaticity coordinates (see IEC 60050-845:1987, 845-03-33) based on CIE 1931 standard
colorimetric system (see IEC 60050-845:1987, 845-03-28), x, y, z on a backlight unit are
obtained using the tristimulus values, X, Y, Z that is the result of measurement of spectral
power distribution, S(λ) (see 3.2.28)
Note 1 to entry:
where
K  is given as K = 683 lm/W;

m m
λ  is in the range of 360 nm to 830 nm (definition), or 380 nm to 780 nm (actually);
,   are the colour-matching functions

62595-1-2  IEC:2011 － 9 －
3.3 Terms related to passive optical components
3.3.1
light-guide plate
LGP
transparent media that is used generally in an edge-lit backlight unit for forming the required
light distribution spatially for transmissive or transflective display panels
3.3.2
functional
...