IEC 62595-1-2:2011

LCD backlight unit - Part 1-2: Terminology and letter symbols

IEC 62595-1-2:2011 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.

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

La CEI 62595-1-2:2011 donne les termes préférentiels, leurs définitions et les symboles pour les écrans à rétro-éclairage (BLU) et les systèmes d'éclairage des panneaux d'affichage associés dont l'éclairage par l'avant. Elle a pour objectif d'utiliser la même terminologie lorsque des publications sont préparées dans différents pays.

General Information

• Status: Published
• Publication Date: 13-Dec-2011
• ICS: 31.120 - Electronic display devices
• ICS: 31.260 - Optoelectronics. Laser equipment
• Technical Committee: TC 110 - Electronic displays
• Drafting Committee: PT 62595-1-2 - TC 110/PT 62595-1-2
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 18-Feb-2016

Relations

• Revised: IEC 62595-1-2:2016 - Display lighting unit - Part 1-2: Terminology and letter symbols
• Effective Date: 05-Sep-2023

Standards Content (Sample)

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

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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
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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
...