Display lighting unit - Part 1-4: Glass light guide plate

IEC TR 62595-1-4:2020(E), which is a Technical Report, provides general information for judging the necessity of future standardization of glass light guide plates for display lighting units, which include backlight units for transmissive displays such as LCDs, and frontlight units for reflective displays.

General Information

Publication Date
Technical Committee
Drafting Committee
Current Stage
PPUB - Publication issued
Start Date
Completion Date
Ref Project

Buy Standard

Technical report
IEC TR 62595-1-4:2020 - Display lighting unit - Part 1-4: Glass light guide plate
English language
24 pages
sale 15% off
sale 15% off

Standards Content (Sample)

IEC TR 62595-1-4 ®
Edition 1.0 2020-07
Display lighting unit –
Part 1-4: Glass light guide plate
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 info@iec.ch
CH-1211 Geneva 20 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 corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform Electropedia - www.electropedia.org
The advanced search enables to find IEC publications by a The world's leading online dictionary on electrotechnology,
variety of criteria (reference number, text, technical containing more than 22 000 terminological entries in English
committee,…). It also gives information on projects, replaced and French, with equivalent terms in 16 additional languages.
and withdrawn publications. Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Just Published - webstore.iec.ch/justpublished
Stay up to date on all new IEC publications. Just Published IEC Glossary - std.iec.ch/glossary
details all new publications released. Available online and 67 000 electrotechnical terminology entries in English and
once a month by email. French extracted from the Terms and Definitions clause of
IEC publications issued since 2002. Some entries have been
IEC Customer Service Centre - webstore.iec.ch/csc collected from earlier publications of IEC TC 37, 77, 86 and
If you wish to give us your feedback on this publication or CISPR.

need further assistance, please contact the Customer Service

Centre: sales@iec.ch.
IEC TR 62595-1-4 ®
Edition 1.0 2020-07
Display lighting unit –
Part 1-4: Glass light guide plate

ICS 31.120; 31.260 ISBN 978-2-8322-8618-0

– 2 – IEC TR 62595-1-4:2020 © IEC 2020
1 Scope . 6
2 Normative references . 6
3 Terms, definitions and abbreviated terms . 6
3.1 Terms and definitions . 6
3.2 Abbreviated terms . 6
4 Overview . 7
4.1 General . 7
4.2 Light guide plate technologies and its typical materials . 7
4.3 Advantages of and issues with GLGP . 8
5 Optical characteristics . 9
5.1 Factors affecting optical characteristics of GLGP . 9
5.2 Optical absorption of the glass materials for LGP . 9
5.3 Optical absorption and scattering loss caused by the dot pattern . 11
5.4 Incident loss . 11
5.5 Effect of the reflection tapes . 12
5.6 Discussions for possible future standardization . 12
5.6.1 Applicability of existing standards . 12
5.6.2 Mechanical structure and interface . 13
5.6.3 Hotspot influence caused by LED light source . 13
5.6.4 Non uniformity around edge . 13
5.6.5 Optical absorption of glass materials for LGP . 13
6 Mechanical and environmental characteristics . 13
6.1 General . 13
6.2 Rigidity . 14
6.3 Thermal expansion and heat resistance/noninflammability . 15
6.4 Humidity absorption . 17
6.5 Impact resistance . 18
6.6 Discussions for possible future standardization . 19
7 Additional functions and possible future standardization . 19
7.1 General . 19
7.2 Local dimming for HDR TV . 19
7.3 Curved GLGP for curved LCD . 20
7.4 Quantum dot coating and quantum dot coated film LCD . 21
7.5 Frontlight . 21
7.6 Transparent LCD . 21
7.7 Combination with PDLC . 22
Bibliography . 23

Figure 1 – Structure of edge-lit BLU and LGP . 7
Figure 2 – Light propagation in LGP . 8
Figure 3 – Examples of internal transmittance spectra at 50 cm in optical path length . 10
Figure 4 – Chromaticity gradient against the distance from incident edge . 10
Figure 5 – Variation of the relative BLU luminance against the thickness of the GLGP . 12
Figure 6 – Weight /thickness dependence of the rigidity of PMMA and glass for LGPs . 15

Figure 7 – Schematics of the simulation setup for the deformation calculation of the
LGP by pulling up one corner and fixing the other three corners . 15
Figure 8 – Horizontal bowing of polymeric LGPs under elevated temperature . 16
Figure 9 – Simulated temperature distribution of (a) GLGP and (b) PMMA LGP . 17
Figure 10 – Simulated thermal deformation of (a) GLGP and (b) PMMA LGP due to

LED lighting . 17
Figure 11 – Increase in the horizontal length of LGP with temperature change for a 65”
diagonal LGP . 18
Figure 12 – Example of curved LCD using a curved GLGP . 20
Figure 13 – Example of transparent LCD . 21
Figure 14 – Example of transparent LCD with GLGP including PDLC . 22

Table 1 – Comparison between polymers and glasses for LGP . 8
Table 2 – Physical properties of commercial glass for LGP and PMMA . 14
Table 3 – Comparison of thickness, weight, and calculated deformation between
GLGP, PMMA LGP, and PMMA combined with steel plate . 15
Table 4 – Comparison of GLGP and polymer LGP in confined structure under humid

condition . 18
Table 5 – Impact resistance with different machining . 19

– 4 – IEC TR 62595-1-4:2020 © IEC 2020
Part 1-4: Glass light guide plate

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
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.
The main task of IEC technical committees is to prepare International Standards. However, a
technical committee may propose the publication of a technical report when it has collected
data of a different kind from that which is normally published as an International Standard, for
example "state of the art".
IEC TR 62595-1-4, which is a Technical Report, has been prepared by IEC technical
committee 110: Electronic displays.
The text of this Technical Report is based on the following documents:
Enquiry draft Report on voting
110/1174/DTR 110/1200/RVDTR
Full information on the voting for the approval of this technical report can be found in the
report on voting indicated in the above table.

This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 62595 series, published under the general title Display light

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.