IEC 61747-1-2:2014

Liquid crystal display devices - Part 1-2: Generic - Terminology and letter symbols

IEC 61747-1-2:2014 gives the preferred terms, their definitions and symbols for liquid crystal devices, with the object of using the same terminology when publications are prepared in different countries. This first edition cancels and replaces the first edition of IEC 61747-1 published in 1998 and Amendment 1:2003. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) The former IEC 61747-1, Generic specification was divided into IEC 61747-1-1, Liquid crystal display devices - Part 1-1: Generic - Generic specification and IEC 61747-1-2, Liquid crystal display devices - Part 1-2: Generic - Terminology and letter symbols;
b) In this part of IEC 61747, new terms have been added and some of the terms and the definitions have been updated.

General Information

• Status: Published
• Publication Date: 11-Aug-2014
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 31.120 - Electronic display devices
• Technical Committee: TC 110 - Electronic displays
• Drafting Committee: WG 2 - TC 110/WG 2
• Current Stage: PPUB - Publication issued
• Start Date: 15-Nov-2014
• Completion Date: 12-Aug-2014

Relations

• Replaces: IEC 61747-1:1998 - Liquid crystal and solid-state display devices - Part 1: Generic specification
• Effective Date: 05-Sep-2023
• Replaces: IEC 61747-1:1998/AMD1:2003 - Amendment 1 - Liquid crystal and solid-state display devices - Part 1: Generic specification
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 61747-1-2 ®
Edition 1.0 2014-08
INTERNATIONAL
STANDARD
Liquid crystal display devices –
Part 1-2: Generic – Terminology and letter symbols

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IEC 61747-1-2 ®
Edition 1.0 2014-08
INTERNATIONAL
STANDARD
Liquid crystal display devices –

Part 1-2: Generic – Terminology and letter symbols

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
T
ICS 31.120 ISBN 978-2-8322-1806-8

– 2 – IEC 61747-1-2:2014 © IEC2014
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
3.1 Physical concepts . 5
3.2 General terms . 9
3.3 Terms related to specifications, ratings and characteristics, image quality,
reliability test, measurement . 15
3.4 Extra components . 19
4 Units and symbols . 19
Bibliography . 23

Figure 1 – Block diagram for explanation of supply voltages . 21
Figure 2 – Timing chart for explanation of response times . 22

Table 1 – Letter symbols . 19

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LIQUID CRYSTAL DISPLAY DEVICES –

Part 1-2: Generic – 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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patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61747-1-2 has been prepared by IEC technical committee 110:
Electronic display devices.
This first edition cancels and replaces the first edition of IEC 61747-1 published in 1998 and
Amendment 1:2003. This edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) The former IEC 61747-1, Generic specification was divided into IEC 61747-1-1, Liquid
crystal display devices – Part 1-1: Generic – Generic specification and IEC 61747-1-2,
Liquid crystal display devices – Part 1-2: Generic – Terminology and letter symbols.
b) In this part of IEC 61747, new terms have been added and some of the terms and the
definitions have been updated.

– 4 – IEC 61747-1-2:2014 © IEC2014
The text of this standard is based on the following documents:
CDV Report on voting
110/526/CDV 110/562/RVC
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 61747 series, under the general title Liquid crystal display
devices, can be found on the IEC website.
NOTE The structure of IEC 61747 series and the changes in the numbering are shown in Annex D of IEC 61747-
30-1:2012.
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.
A bilingual version of this publication may be issued at a later date.

LIQUID CRYSTAL DISPLAY DEVICES –

Part 1-2: Generic – Terminology and letter symbols

1 Scope
This part of IEC 61747 gives the preferred terms, their definitions and symbols for liquid
crystal devices, 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 60027 (all parts), Letter symbols to be used in electrical technology
IEC 60050 (all parts), International Electrotechnical Vocabulary (available at
)
IEC 60617, Graphical symbols for diagrams
ISO 80000-1, Quantities and units – Part 1: General
3 Terms and definitions
For the purpose of this document, the following terms and definitions apply.
3.1 Physical concepts
3.1.1
alignment layer
thin layer deposited over the patterned electrodes that determines the direction of the director
at the surface
Note 1 to entry: The alignment layer produces the desired ordering. Alignment such as homeotropic alignment or
planar alignment is achieved by the co-operative ordering of the liquid crystal molecules locally affected by the
surface forces. The alignment layer generates the pretilt angle.
3.1.2
anti-ferroelectric liquid crystal
AFLC
type of smectic liquid crystal having no macroscopic electric polarization at zero external field
Note 1 to entry: An anti-ferroelectric liquid crystal has a paraelectric state with layers of alternating polarity of
permanent dipoles without an external electric field, and it transfers to a ferroelectric state of parallel alignment
when an electric field is applied.
3.1.3
cell gap
thickness of the liquid crystal layer between the two support plates

– 6 – IEC 61747-1-2:2014 © IEC2014
3.1.4
cholesteric phase
liquid crystal phase that exhibits planar nematic ordering in which the directors form a helix
that has its axis perpendicular to the plane
3.1.5
chiral pitch
helical pitch
periodic distance needed for directors to rotate by 360° in a helically structured liquid crystal
3.1.6
chiral nematic phase
liquid crystal phase that exhibits planar nematic ordering in which the directors form a helix
that has its axis perpendicular to the plane
3.1.7
clearing point
phase transition temperature of a liquid crystal for transition toward the isotropic phase
3.1.8
dichroic liquid crystal
liquid crystal exhibiting dichroism, i.e. the property of anisotropic absorption of light
3.1.9
direct addressing
method of addressing by applying a signal to a terminal that corresponds to a single pixel
Note 1 to entry: Hence, all pixels can be addressed individually, in groups or simultaneously
3.1.10
director
axial unit vector describing the local axis of symmetry for the orientational distribution function
of any chosen molecular axis of a liquid crystal
Note 1 to entry: The director co-ordinates define the local alignment of the liquid crystal.
3.1.11
disclination
localized alignment defect (appearing generally in the form of closed or open lines) forming
the boundary between areas exhibiting different alignment states
3.1.12
discotic mesophase
liquid crystal phase of disc-like shaped molecules exhibiting a long range ordering with
respect to the short molecular axis
3.1.13
domain
region having a well-defined boundary in which liquid crystal molecules have the same
director orientation
3.1.14
dynamic scattering
electro-optical effect showing a light scattering caused by turbulent motion in a liquid crystal
layer induced by an electro-hydrodynamic effect

3.1.15
electrically controlled birefringence
electro-optical effect caused by the birefringence of a liquid crystal layer which
...