Display lighting unit - Part 1-2: Terminology and letter symbols

IEC 62595-1-2:2016(E) gives the preferred terms, their definitions and symbols for display lighting units (DLUs) such as backlight units (BLUs) of transmissive and transflective LCDs, and frontlight units (FLUs) of reflective LCDs and electronic paper (E-paper) displays, with the object of using the same terminology when publications are prepared in different countries. This edition includes the following significant technical changes with respect to the previous edition:
a) change in the series title in order to handle frontlight units;
b) new terms are added considering recent advances in display lighting unit (DLU) technology;
c) some of terms and definitions are corrected and revised, particularly to be consistent with IEC 62595-2;
d) some of the terms and definitions are corrected and revised, particularly to be consistent with IEC 60050 policy;
e) clause structure is rectified for categorizing terms correctly;
f) some of figures in Annex A are added or revised for better understanding.

General Information

Status
Published
Publication Date
17-Feb-2016
Technical Committee
Drafting Committee
Current Stage
PPUB - Publication issued
Start Date
15-Mar-2016
Completion Date
18-Feb-2016
Ref Project

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IEC 62595-1-2 ®
Edition 2.0 2016-02
INTERNATIONAL
STANDARD
colour
inside
Display lighting unit –
Part 1-2: Terminology and letter symbols
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IEC 62595-1-2 ®
Edition 2.0 2016-02
INTERNATIONAL
STANDARD
colour
inside
Display lighting unit –
Part 1-2: Terminology and letter symbols

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 31.120; 31.260 ISBN 978-2-8322-3170-8

– 2 – IEC 62595-1-2:2016  IEC 2016
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 solid-state light sources . 13
3.4.1 Light-emitting diode (LED) . 13
3.4.2 LED light bar . 14
3.5 Terms related to frontlight units . 15
3.6 Terms related to performances and specifications . 16
3.7 Terms related to backlight dimming . 18
4 Letter symbols (quantity symbols / unit symbols) . 20
Annex A (informative) Supplementary figures . 21

Figure A.1 – Backlighting concept for transmissive and transflective LCDs . 21
Figure A.2 – Examples of edge-lit backlight units . 21
Figure A.3 – Example of a direct-lit backlight unit . 22
Figure A.4 – Visual definition of the terms related to passive optical components such
as bezel and case . 22
Figure A.5 – Luminance uniformity on a backlight unit . 23
Figure A.6 – Polar coordinate system for evaluation of the angular luminance
distribution. 23
Figure A.7 – Angular luminance on a backlight unit . 24
Figure A.8 – Examples of spectral power distribution of a display lighting unit . 24
Figure A.9 – Incoherent light spread function for evaluation of optical characteristics of
a block in a block-wise dynamic backlight unit . 24
Figure A.10 – Light spread functions of three BLUs with different optical structures . 25
Figure A.11 – Checkerboard pattern for evaluation of the luminance uniformity
in a BLU . 26

Table 1 – Letter symbols (quantity symbols / unit symbols) . 20

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
DISPLAY LIGHTING UNIT –
Part 1-2: Terminology and letter symbols

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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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:
Electronic display devices.
This second edition cancels and replaces the first edition published in 2011. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) change in the series title in order to handle frontlight units;
b) new terms are added considering recent advances in display lighting unit (DLU)
technology;
c) some of terms and definitions are corrected and revised, particularly to be consistent with
IEC 62595-2;
d) some of the terms and definitions are corrected and revised, particularly to be consistent
with IEC 60050 policy;
– 4 – IEC 62595-1-2:2016  IEC 2016
e) clause structure is rectified for categorizing terms correctly;
f) some of figures in Annex A are added or revised for better understanding.
The text of this standard is based on the following documents:
FDIS Report on voting
110/720/FDIS 110/734/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 62595 series, under the general title Display lighting unit, can
be found on the IEC website.
Future standards in this series will carry the new general title as cited above. Titles of existing
standards in this series will be updated at the time of the next edition.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC website 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.
DISPLAY LIGHTING UNIT –
Part 1-2: Terminology and letter symbols

1 Scope
This part of IEC 62595 gives the preferred terms, their definitions and symbols for display
lighting units (DLUs) such as backlight units (BLUs) of transmissive and transflective LCDs,
and frontlight units (FLUs) of reflective LCDs and electronic paper (E-paper) displays, 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 60050-845, International Electrotechnical Vocabulary – Part 845: Lighting
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60050-845 as well
as the following apply.
3.1 Classification of terms
Terms for display lighting units (DLUs), such as backlight units (BLUs) and frontlight units
(FLUs) are classified as follows:
a) fundamental terms related to display lighting units (3.2);
b) terms related to passive optical components used in display lighting units (3.3);
c) terms related to solid-state light sources used in display lighting units (3.4);
d) terms related particularly to frontlight units (3.5);
e) terms related to performances and specifications (3.6);
f) terms related to backlight dimming (3.7).
The following definitions are applied for international standardization of the backlight units.
3.2 Fundamental terms
3.2.1
display lighting unit
DLU
lighting unit for recognition of the displayed images on a non-emissive electronic display
device
____________
Identical to CIE 17.4.

...

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