EN 61747-6:2004

SLOVENSKI SIST EN 61747-6:2005

STANDARD
december 2005
Prikazalniški elementi s tekočimi kristali in polprevodniki – 6. del: Merilne
metode za module s tekočimi kristali – Presojni tip (IEC 61747-6:2004)
Liquid crystal and solid-state display devices – Part 6: Measuring methods for
liquid crystal modules – Transmissive type (IEC 61747-6:2004)
ICS 31.120 Referenčna številka
©  Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

EUROPEAN STANDARD EN 61747-6
NORME EUROPÉENNE
EUROPÄISCHE NORM May 2004
ICS 31.120
English version
Liquid crystal and solid-state display devices
Part 6: Measuring methods for liquid crystal modules –
Transmissive type
(IEC 61747-6:2004)
Dispositifs d'affichage à cristaux liquides Flüssigkristall- und Halbleiter-Anzeige-
et à semiconducteurs Bauelemente
Partie 6: Méthodes de mesure Teil 6: Messverfahren
pour les modules à cristaux liquides - für Flüssigkristall-Module –
Type transmissif Transmissive Ausführung
(CEI 61747-6:2004) (IEC 61747-6:2004)

This European Standard was approved by CENELEC on 2004-05-01. 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 Central Secretariat 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 Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden,
Switzerland and United Kingdom.

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels

© 2004 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 61747-6:2004 E
Foreword
The text of document 110/13/FDIS, future edition 1 of IEC 61747-6, prepared by IEC TC 110, Flat
panel display devices, was submitted to the IEC-CENELEC parallel vote and was approved by
CENELEC as EN 61747-6 on 2004-05-01.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2005-02-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2007-05-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 61747-6:2004 was approved by CENELEC as a European
Standard without any modification.
__________
- 3 - EN 61747-6:2004
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
NOTE Where an international publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
Publication Year Title EN/HD Year
ISO 13406-1 1999 Ergonomic requirements for work with EN ISO 13406-1 1999
visual displays based on flat panels
Part 1: Introduction
ISO 13406-2 2001 Part 2: Ergonomic requirements for flat EN ISO 13406-2 2001
panel displays
NORME CEI
INTERNATIONALE IEC
61747-6
INTERNATIONAL
Première édition
STANDARD
First edition
2004-04
Dispositifs d'affichage à cristaux liquides
et à semiconducteurs –
Partie 6:
Méthodes de mesure pour les modules
à cristaux liquides –
Type transmissif
Liquid crystal and solid-state display devices –
Part 6:
Measuring methods for liquid crystal modules –
Transmissive type
© IEC 2004 Droits de reproduction réservés ⎯ Copyright - all rights reserved
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électronique ou mécanique, y compris la photocopie et les photocopying and microfilm, without permission in writing from
microfilms, sans l'accord écrit de l'éditeur. the publisher.
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Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch
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PRICE CODE W
Commission Electrotechnique Internationale
International Electrotechnical Commission
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Pour prix, voir catalogue en vigueur
For price, see current catalogue

61747-6 © IEC:2004 – 3 –
CONTENTS
FOREWORD.5
1 Scope and object .9
2 Normative references.11
3 Chromaticity and pixel definitions .11
4 Standard measuring conditions .13
4.1 Standard measurement equipment and setup.13
4.2 Standard measurement positions .17
4.3 Standard device operation conditions.19
4.4 Standard ambient conditions.19
4.5 Standard measuring process .19
5 Measuring methods.21
5.1 Luminance and luminance uniformity .21
5.2 Warm-up characteristics.23
5.3 Response times (turn-on time, turn-off time, rise time and fall time) .25
5.4 Flicker (multiplexed displays) .31
5.5 Luminance contrast ratio.33
5.6 Peak viewing direction – Viewing angle range .37
5.7 Viewing angle range without gray-scale inversion .39
5.8 Specular reflectance from the active area surface .41
5.9 White chromaticity and its uniformity (matrix displays only).45
5.10 Reproduction of colour (matrix displays only) .47
5.11 Display resolution (high resolution matrix displays only) .49
5.12 Cross-talk.51
5.13 Power consumption.55
Annex A (informative) Standard measuring conditions .61
Annex B (informative)  Measuring methods for liquid crystal display devices
(segment type) .63
Figure 1 – Measuring system and its configuration.13
Figure 2 – Definition of polar coordinates θ, ϕ.15
Figure 3 – Standard measurement positions at the centres of all rectangles p0-p24 .17
Figure 4 – Example of warm-up characteristic .25
Figure 5 – Relationship between driving signal and optical response times .29
Figure 6 – Frequency characteristics of the integrator (response of human visual system) .33
Figure 7 – Example of power spectrum.33
Figure 8 – Example of gray-scale inversion.41
Figure 9 – Example of standard set-up for specular reflection measurements .43
Figure 10 – Checker-flag pattern for current and power consumption measurements .55
Figure 11 – Example of measuring block diagram for current and power consumption of
a liquid crystal display device .57

61747-6 © IEC:2004 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LIQUID CRYSTAL AND SOLID-STATE DISPLAY DEVICES –
Part 6: Measuring methods for liquid crystal modules –
Transmissive type
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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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 61747-6 has been prepared by IEC technical committee 110: Flat
panel display devices.
This part of IEC 61747 series completes the full revision of IEC 60747-5(1992) and its
amendments.
The text of this standard is based on the following documents:
FDIS Report on voting
110/13/FDIS 110/19/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.

61747-6 © IEC:2004 – 7 –
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
This standard should be read in conjunction with IEC 61747-1.
The committee has decided that the contents of this publication will remain unchanged until
2005. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
61747-6 © IEC:2004 – 9 –
LIQUID CRYSTAL AND SOLID-STATE DISPLAY DEVICES –
Part 6: Measuring methods for liquid crystal modules –
Transmissive type
1 Scope and object
This part of IEC 61747 gives details of the quality assessment procedures, inspection
requirements, screening sequences, sampling requirements and test and measurement
procedures required for the assessment of liquid crystal display modules.
This standard is restricted to transmissive liquid crystal display (LCD) modules using either
segment, passive or active matrix and achromatic or colour type LCDs (see Clause 3,
chromaticity and pixel definitions) that are equipped with their own integrated source of
illumination or without their own source of illumination.
For both rear projection-display systems and front projection-display systems, optical
performance on the screen is not only determined by the panel performance as described in
this standard, but also by the lighting system, such as the projection lens, screen, light filter,
etc. Therefore, this standard is not applicable to such projection-display systems.
(Nevertheless, for the determination of "on the screen" optical performance of rear projection-
display systems, this standard may be used as a guideline).
In order to achieve a useful and uniform description of the performance of the display devices
covered in this standard, specifications for commonly accepted relevant parameters are
provided and fall into the following categories:
a) general type (e.g. pixel resolution, diagonal, pixel layout);
b) optical (e.g. contrast ratio, response time, viewing direction, cross-talk, etc.);
c) electrical (e.g. power consumption, EMC);
d) mechanical (e.g. module geometry, weight);
e) passed environmental endurance test;
f) reliability and hazard/safety.
In most categories, the specification is self-explanatory. For some, however, notably in the
area of optical and electrical performance, the specified value may depend on the measuring
method.
The object of this standard is to indicate and list the procedure-dependent parameters and to
prescribe the specific methods and conditions that are to be used for their uniform numerical
determination.
It is assumed that all measurements are performed by personnel skilled in the general art of
radiometric and electrical measurements as the purpose of this standard is not to give a
detailed account of good practice in electrical and optical experimental physics. Furthermore,
all equipment needs to be suitably calibrated by competent personnel, and records of the
calibration data and traceability need to be kept.

61747-6 © IEC:2004 – 11 –
2 Normative references
The following referenced documents are indispensable for the application of this document. For
dated references, only the edition cited applies. For undated references, the latest edition of
the referenced document (including any amendments) applies.
ISO 13406-1:1999, Ergonomic requirements for work with visual displays based on flat
panels – Part 1: Introduction
ISO 13406-2:2001, Ergonomic requirements for work with visual displays based on flat
panels – Part 2: Ergonomic requirements for flat panel displays
3 Chromaticity and pixel definitions
Several points of view with respect to the preferred terminology concerning "monochrome",
"achromatic", "chromatic", "colour", "full-colour", etc. can be encountered in the field amongst
spectroscopists, physicists, colour-perception scientists, physical engineers and electrical
engineers. In general, all LCDs demonstrate some sort of chromaticity (e.g. as a function of
viewing angle, ambient temperature or externally addressable means). Pending detailed official
description of the subject, the pre-fix pertaining to the chromaticity of the display will be used to
describe the colour capability of the display that is externally (and electrically) addressable by
the user. This leads us to the following definitions (see also ISO 13406-1, Chapter 3:
Terminology):
a) a monochrome display has no user-addressable chromaticity ("colours"). It may or may not
be "black and white" or a-chromatic;
b) a colour display has at least two user-addressable chromaticities ("colours"). A 64-colour
display has 64 addressable colours (often made using 2 bits per primary), etc. A full-colour
display has at least 6 bits per primary (≥ 260 000 colours).
Within this document, the official definition of pixel is employed, which may or may not include
a multitude of constituent dots.

61747-6 © IEC:2004 – 13 –
4 Standard measuring conditions
4.1 Standard measurement equipment and setup
4.1.1 High resolution matrix displays ( ≥≥ 320 ×× 240 pixels)
≥≥ ××
> 500 pixels
e.g. ∅4 cm diaphragm
°
θ < 5
accept
e.g  50 cm
Device under test Light measuring device
IEC  282/04
Figure 1 – Measuring system and its configuration
Three different instruments may be applied to the measurements of the light transmitted and/or
reflected by the device under test (DUT); a luminance meter, tristimulus photometer or a
spectro-radiometer. The optical system is schematically shown in Figure 1 and shall allow for
measurement of well-defined spot sizes (field of view) on the DUT. When measuring matrix
displays, these meters should be set to a circular or rectangular field of view that includes more
than 500 pixels on the display under normal observation (the standard measurement direction).
The total acceptance angle of detection by these meters, θ , shall be less than 5° (see Figure 1).
accept
This can be obtained, for example, by use of a measuring distance between the meters and
display area centre of 50 cm (recommended) and a diameter of the detector pupil of 4 cm; see
Figure 1. If measuring segment displays, the field of view should be set to a single segment,
and not include any of its surroundings.
Viewing direction and angle range are given by polar coordinates θ and ϕ as defined in
Figure 2. θ = 0 is referred to as the 3 o'clock direction (the "right"), θ = 90 as the 12 o'clock
ϕ ϕ
direction ("upward"), θ = 180 as the 9 o'clock direction ("left") and θ = 270 as the 6 o'clock
ϕ φ
("bottom"). In the standard measurement direction, the photometer observes the DUT under
vertical viewing angle (θ = 0°). While scanning θ and/or ϕ, the centre of the measuring spot on
the DUT shall stay fixed.
61747-6 © IEC:2004 – 15 –
θ
12 o’clock = 12 h
ϕ
IEC  283/04
12 o'clock pertains to "top" of the display area, 3 o'clock to "right" of the display area (as viewed under "normal"
operating viewing conditions)
Figure 2 – Definition of polar coordinates θθθθ, ϕϕϕϕ
Any condition (either measuring spot on the DUT, meter aperture angle, viewing angle, meter
spectral sensitivity, resolution etc.) that is not compliant to the required condition described in
this shall be recorded in the detail specifications.
If the DUT is not equipped with its own source of illumination, external illumination shall be
done in either of two ways:
a) by means of an externally applied diffuse light source with specified (spatial and angular
distribution of) luminance and spectrum (this is, for example, used for measurements on
direct view displays);
b) by means of an externally applied directional light source with calibrated spatial uniformity
of illumination at the plane of the DUT, full opening angle of illumination at the location of
the measuring spot in the plane of the DUT of less than 30°, and (if needed) (calibrated)
distribution of spectral irradiation in the visible region of radiation (mostly used for
measurements on projection-display modules).
In both cases, records of the light source (intensity distribution, temporal stability, opening
angle, etc.) and its distance to the device under test shall be added to the detail specification.
The temporal drift in luminance shall be less than 1 % of the stabilized value per minute. Care
shall be taken that the temperature of the DUT has stabilized and is not affected by the
illumination system. The temperature of the DUT shall be measured and specified.
Any deviation from the above described standard measurement equipment or setup shall be
added to the detail specification.
4.1.2 Low resolution (<<<< 320 ×××× 240 pixels) and segment display specific remarks
Default measurement conditions are the same as those prescribed for high-resolution matrix
displays. However, for low resolution and segment displays the measurement field may contain
fewer than 500 pixels. For matrix displays, a minimum of 9 is recommended. For measuring
segment displays, the field of view should be set to a single segment, and not include any of its
surroundings under any measurement angle.

61747-6 © IEC:2004 – 17 –
4.2 Standard measurement positions
4.2.1 Matrix displays
P23 P24 P9 P10
P11
P22 P8 P1 P2 P12
P21 P7 P0 P3 P13
P20 P5
P6 P4 P14
(5/10)V
(3/10)V
P19 P18 P17 P16 P15
(1/10)V
(1/10)H
(3/10)H
(5/10)H
IEC  284/04
NOTE Height and width of each rectangle is 20 % of display height and width respectively.
Figure 3 – Standard measurement positions at the centres of all rectangles p0-p24
Luminance, radiance distribution and/or tristimulus values may be measured at several
specified positions on the DUT surface. To this end, the front view of the display is divided into
25 identical imaginary rectangles, according to Figure 3. Unless otherwise specified,
measurements are carried out in the centre of each rectangle. Care shall be taken that the
measuring spots on the display do not overlap. Positioning of the measuring spot on the thus
prescribed positions in the x and y direction shall be to within 7 % of X and Y respectively
(where X and Y denote the length of the active display area in the x and y direction,
respectively).
While scanning the position of the measuring spot over the surface of the DUT, the polar
angles shall stay fixed.
Any deviation from the above-described standard positions shall be added to the detail
specification.
4.2.2 Segment displays
Standard measurement positions are the same as those prescribed for matrix displays
in 4.2.1. However, for segment displays, all measurements shall be performed at the centre of
a segment and the chosen segment should be as close as possible to the centre of the
designated rectangle. Thus, when measurements on position p (i = 0 to 24) are requested, the
i
geometrical centre of the segment closest to the centre of box p should be used for positioning
i
of the detector.
Any deviation from the above described standard positions shall be added to the detail
specification.
61747-6 © IEC:2004 – 19 –
4.3 Standard device operation conditions
The module being tested shall be physically prepared for testing. It shall be warmed up for the
stable operation of liquid crystal display devices at a specified period of less than 1 h. Testing
shall be conducted under nominal conditions of input voltage, current, etc. The bias setting
(if any) of the module shall be specified and set to those expected under typical use.
Any deviation from the standard device operation conditions shall be added to the detail
specification.
4.4 Standard ambient conditions
4.4.1 Temperature, humidity and pressure conditions
The standard measuring ambient for the liquid crystal display devices is (25 ± 2) °C for
temperature, (25 to 85) % for relative humidity and (86 to 106) kPa for pressure.
4.4.2 Illumination conditions
Three possible ambient illumination variants are defined as follows:
– darkroom condition: illuminance of the measuring spot on the DUT below 1 lx; directionality
unspecified;
– hemispherical diffused light condition: state of illumination of the measuring spot on the
DUT where the illuminance is not quantified but Lambertian;
– room illumination condition: illuminance of the measuring spot on the DUT with an intensity
between 300 lx and 1000 lx. The intensity of the incident light is equal in all directions
(Lambertian illumination).
Records of the measured ambient illumination should be kept on the measuring data sheet.
Any deviation from the standard ambient conditions shall be added to the detail specification.
4.5 Standard measuring process
Due to the physics of LCDs almost all optical properties of these devices vary with the direction
of observation (i.e. viewing direction). Therefore, it should be understood that for the
determination of several of the parameters below, good (mechanical) control and specification
of the viewing direction is necessary. Also, the distance between the light measuring device
and the measuring spot on the DUT shall remain constant for all viewing directions.
All light sources used for illumination of the DUT during the measurement shall be constant in
intensity and spectrum, at least over the time-period of measurements that are related to each
other in the evaluation (e.g. bright and dark state of a display for contrast evaluation). The
luminance or illuminance of the arrangement used for illumination of the DUT shall be constant
to within ±1 % over a time period of minimum 15 min and shall not exhibit short-term
fluctuations (e.g. ripple, PWM modulations, etc.).
The standard measuring process consists of the following steps:
a) prepare the measurement equipment and set-up, device-under-test and ambient conditions
to the specified (standard) values;
b) make records of standard condition choices and of deviations from standard conditions;

61747-6 © IEC:2004 – 21 –
c) measure the necessary parameters in a darkroom;
d) if an external light source is used, measure the following parameters of the light source in
the plane of the DUT. At p0 (Figure 3), measure and specify
1) spectrum of emission,
2) luminance L,
3) temporal stability of the luminance L(t),
4) luminance distribution with viewing angle L(θ,ϕ).
When measuring window contrast ratio (5.5.3.2), chromaticity uniformity (5.9), display
uniformity (5.1) or cross-talk (5.12), measure the spectrum of emission, luminance and
luminance distribution with viewing angle also at the other relevant positions p1-p24
(Figure 3).
e) add a drawing or photo of the exact geometry of arrangement between light source, DUT
and light measuring device to the specification.
The illumination apparatus shall be specified in detail since corrections to the standard
conditions are not possible.
5 Measuring methods
5.1 Luminance and luminance uniformity
5.1.1 Purpose
This method is applied to the measurements of luminance and its lateral uniformity (i.e. in the
active area) of the liquid crystal display devices with a built-in backlight system.
5.1.2 Measuring equipment
The measuring instruments shall consist of a luminance meter, a driving power supply and a
driving signal generator for liquid crystal display devices.
5.1.3 Measuring method
5.1.3.1 Maximum luminance
Measurements are performed in a darkroom under standard measuring conditions and design
viewing direction.
Supply the signals to the device as it would be used under normal operating conditions, e.g.
maximum contrast ratio, and specify these signals, then apply the data-input signal for
maximum luminance.
5.1.3.1.1 Matrix displays
Measure the luminance L at position p0 (the centre of the active area of the display).
5.1.3.1.2 Segment displays
Measurement shall be carried out at the centre of a segment, where the measurement spot is
smaller than the segment.
61747-6 © IEC:2004 – 23 –
5.1.3.2 Luminance non uniformity
Measurements are performed in a darkroom under standard measuring conditions. All 25
rectangles are addressed with 100 % data-input signal-level (WHITE). Measure the luminance
L at the rectangles i = 11, 15, 19, 23 or i = 9, 11, 13, 15, 17, 19, 21, 23 and the centre position
i
(i = 0). The luminance non uniformity (LNU) is calculated from the individual luminances L and
i
the average luminance L according to
av
ª º
§ ·
L − L
av i
¨ ¸
LNU = max ×100% (1)
« »
¨ ¸
L
« av »
© ¹
¬ ¼
where LNU = 0 % indicates a perfectly uniform display.
5.1.4 Specified conditions
Records of the measurement shall be made in order to describe deviations from the standard
measurement conditions and shall include the following information:
– driving signals (waveforms, voltage and frequency);
– measuring points.
5.2 Warm-up characteristics
5.2.1 Purpose
This method is applied to the measurements of turn-on luminance transient characteristics for
the transmissive type liquid crystal display devices with built-in backlight system (these effects
are mostly due to warm-up).
5.2.2 Measuring equipment
The measuring instruments shall consist of a luminance meter, a driving power supply and a
driving signal generator for liquid crystal display devices.
5.2.3 Measuring method
5.2.3.1 Matrix displays
The measurement shall be performed under dark-room and standard measurement conditions,
unless otherwise specified.
The device under test (DUT) shall be supplied with all voltages and input data required to
obtain the maximum transmittance of the LCD. The measurement of the luminance as a
function of time shall be carried out at position p0 and the luminance is recorded versus time
until the observed fluctuations of luminance become less than 1 % of the mean value. This
mean value shall be obtained by taking at least 10 measurements over a period of typically
15 min. The mean luminance level after having settled to the stable state is called the
"luminance value after stabilization, L ". All measuring conditions shall be kept stable over
stab
the time period of recording the luminance.

61747-6 © IEC:2004 – 25 –
1 10 100
0,1
Time (minutes)
IEC  285/04
Figure 4 – Example of warm-up characteristic
Values of characteristics can be derived from the recorded luminance versus time values by
computation of, say, t (time period required for the luminance to reach 90 % of L ).
90 stab
When the time dependent luminance data are required for other positions, measure the
luminance at these positions.
5.2.3.2 Segment displays
The same requirements as for matrix displays are applicable.
5.2.4 Specified conditions
Records of the measurement shall be made in order to describe deviations from the standard
measurement conditions and shall include the following information:
– driving signals (waveforms, voltage and frequency);
– timing of data acquisition (sampling frequency and integration period).
5.3 Response times (turn-on time, turn-off time, rise time and fall time)
5.3.1 Purpose
The purpose of this test is to determine the time needed to change from light to dark (dark to
light) by application of the driving voltage.
By convention, the response of LCDs to an increase in driving voltage is called "turn-on"
whereas the relaxation following a decrease of the driving voltage is called "turn-off". While this
definition is straightforward in the case of segment and low resolution LCDs, it is significantly
more complicated in the case of high resolution matrix LCD screens, due to the complex data-
processing included in such a display.
___________
As a consequence, ISO 13406-2 uses the term "image formation time" (sum of turn-on and turn-off) with the
distinction of positive and negative contrast polarity (the turn-on process in the case of positive contrast polarity
is then the switching from "bright" to "dark" as required to generate an image on the bright background).
Luminance (cd/m )
61747-6 © IEC:2004 – 27 –
5.3.2 Measuring equipment
These typical times are measured using a luminance meter with sufficient frequency response,
power supply, driving signal generator, trigger signal generator and recorder.
5.3.3 Measurement method
Measurements are performed in a darkroom under standard measurement conditions. The
electrical signal of the detector, which is positioned under the design viewing direction at
position p0 (see Figure 3), is recorded as a function of time. The display is driven by an
invertible plain field signal from a signal generator. Upon inverting, the signal shall go from
start level to end level without displaying any intermediate level on the display. The frequency
of inversion shall be low enough to allow the display to obtain optical equilibrium in each of the
two states. A trigger signal is sent to the recorder upon inversion of the video at position p0. If
the trigger signal has another timing (e.g. at the beginning of the field), corrections shall be
made to allow for the scanning time t needed for video signal inversion to arrive at position p0.
s
The luminance meter measures the optical response. Ripples in the detected signal due to
irrelevant effects (e.g. originating from the display frame frequency) shall be eliminated from
the response. The luminance in the WHITE (100 % input data signal) mode is chosen as 100 %
and in the BLACK (0 % input data signal) mode as 0 %.
Caution: For high resolution displays (> 320 × 240 pixels), care should be taken that the
measured response times are not significantly influenced by the time needed by the display for
the (line sequential) “scanning” of the measuring spot. If the display frame time is indicated by
T = 1/f (with f being the frame frequency), the display has N rows with a vertical
FRM FRM row
pixel-pitch of V , leading to a display height (i.e. display dimension in the “scanning
pitch
direction”) of H = N ×V , and the diameter of the measuring spot in the same direction is
row pitch
given by S, then the measured response times t (see below) should obey
S
≥ 5 (2)
t T
H
5.3.4 Specification of dynamic characteristics
Thus, for all types of LCDs, the times needed for the luminance at position p0 to change from
0 % --> 90 % (t ) and 100 % --> 10 % (t ) are measured (see Figure 5). Also, at the same
1 2
position, the times needed for the luminance to change from 10 % --> 90 % (τ ) and 90 % -->
10 % (τ ) are measured. The turn-on and turn-off time t and t are then defined for the
2 on off
normally white (normally black) DUT according to
= ( ) (3)
t t t
on 2 1
and = ( ) (4)
t t t
off 1 2
and the rise time (t ) and fall time (t ) according to
r f
(5)
= ( )
t τ τ
r 2 1
and = ( ) (6)
t τ τ
f 1 2
61747-6 © IEC:2004 – 29 –
Both on and off times, as well as rise and fall times, are examples of (dynamic) response
times, also called “switching” times; in other words, the (dynamic) response time and switching
time are general terms that are not strictly defined. The difference between turn-on and turn-off
times on the one hand, and rise and fall times on the other, is called the delay time.
t t
Luminance 1 2
100 %
Normaly withe
90 %
10 %
Normaly black
0 %
Time
τ τ
1 2
On
Driving
signal
Off
IEC  286/04
Figure 5 – Relationship between driving signal and optical response times
5.3.5 Specified conditions
Records of the measurement shall be made in order to describe deviations from the standard
measurement conditions and shall include the following information:
– driving signals (waveforms, voltage and frequency);
– filtering applied to remove frame response and refresh artifacts;
– dynamic properties of light measuring device and data sampling and recording;
– if use is made of the term switching time or (dynamic) response time, explanation of the
use should be given in the detail specification, and deviations from the above prescribed
nomenclature should be given when using other names for any of these times.

61747-6 © IEC:2004 – 31 –
5.4 Flicker (multiplexed displays)
5.4.1 Purpose
This method is used for assessment of the temporal variation of display luminance for
multiplexed and/or matrix displays. Although this is often called “flicker” by people active in the
field, the latter name is, strictly speaking, reserved for the perceptual effects of this temporal
variation. The actual flicker, i.e. the visual perception of temporal fluctuations, is a complicated
matter depending amongst other things on the brightness and colour of the light source as well
as the direction at which it is observed. The perceptual side will not be discussed here; instead,
determination of the temporal fluctuations is considered. Only the frequency response of the
human visual system is taken into account to determine this flicker. More relevant information
about the technical and perceptive issues of display flicker can be found in ISO 13406-2,
Annex B.
5.4.2 Measuring equipment
The measuring instruments shall consist of a power supply, a driving signal generator and a
luminance meter with a cut-off frequency of at least three times the display frame frequency.
5.4.3 Measuring method
Measurements are performed under darkroom standard measuring conditions. First, the
contrast ratio is adjusted to the maximum value. Next, the luminance is adjusted to 50 % of its
maximum (by selecting the appropriate grey level or video input signal). Thereafter, measure
the luminance at the centre of the active area or the segment of interest by the luminance
meter as a function of time. In order to account for the frequency response of the human visual
system, the signal from the luminance meter may be passed through an integrator with visual
sensitivity characteristics (see Figure 6) before the recording of the frequency response on the
frequency analyzer. (Alternatively, the frequency response of the human visual system may be
taken into account by numerical multiplication of the measured power-spectrum with the
response-function given in Figure 6). Next, for each thus found frequency 60 Hz > f > 0 Hz,
determine the power present in the spectrum and find the component with the highest power
value P . The flicker level F is obtained according to
fmax
§ ·
P
f max
¨ ¸
F =10 ×log [dB] (7)
¨ ¸
P
© ¹
61747-6 © IEC:2004 – 33 –
–6
–3
–10
–12
–20
–30
–40
–40
–50
–60
–70
10 20 30 40 50 60 70
Frequency (Hz)
IEC  287/04
Figure 6 – Frequency characteristics of the integrator
(response of human visual system)
P0
Pf1
Pf2
30 60
Frequency Hz
IEC  288/04
Figure 7 – Example of power spectrum
5.4.4 Specified conditions
Records of the measurement shall be made in order to describe deviations from the standard
measurement conditions and shall include the following information:
– driving signals (waveforms, voltage and frequency);
– the absolute value of the luminance at which the flicker measurement was performed (i.e.
50 % of the maximum value of the device).
5.5 Luminance contrast ratio
5.5.1 Purpose
The purpose of this method is to determine the luminance contrast ratio (in short "contrast
ratio") of the LCD device.
Level (dB)
Power
61747-6 © IEC:2004 – 35 –
5.5.2 Measuring equipment
The measurement instruments shall consist of a luminance meter, driving power supply and
driving signal generator.
5.5.3 Measuring method
The contrast ratio of LCDs is not directly measurable with non-imaging detectors. It shall be
evaluated as the quotient of two luminance values that are sequentially measured in the bright
and the dark state of the display. It shall be assured that all conditions besides the electrical
driving remain constant during the measurement of both luminance values (e.g. temperature,
illumination, etc.).
Measurements are performed under darkroom and standard measurement conditions. The
luminance meter is positioned under θ = 0°.
5.5.3.1 Plain field contrast ratio (high resolution display)
The module is driven by a plain field test pattern signal from a signal generator (i.e. all 25
rectangles have the same grey level). The luminance is measured at position p0 on the DUT
(centre of the display area, see Figure 3) in the WHITE mode (100 % input data-signal or video
level) and in the BLACK mode (0 % input data signal or video level), leading to L and
white,
L , respectively. Care shall be taken that the reading of the luminance meter due to stray
black
light is less than 1 % of the luminance reading . The plain-field contrast ratio CR is defined
PF
as
L
white
= (8)
CR
PF
L
black
5.5.3.2 Window contrast ratio (high resolution display)
The module is driven by a test pattern that generates WHITE (100 % input data signal or video
level) on all 25 rectangles except for rectangle p0 which is driven BLACK (0 % input data signal
or video level). This leads to a (black) window of 4 % of the display area. (Alternatively, it is
allowed to shrink the window homogeneously to an area of 2,77 %, i.e. a window of 1/6 x 1/6 of
the total display area).
Furthermore, the background can be made BLACK and rectangle p0 driven WHITE. These
situations lead to the "dark image contrast ratio on a light field", CR , and the "light image
dol
contrast ratio on a dark field", CR , respectively. Luminance of rectangles p3 and p7 are
lod
measured. Indicating the luminance within rectangle i by L , we define
i
+
L3 L7
(9)
CR =
dol
L
L
and (10)
CR =
lod
+
L3 L7
___________
The contrast ratio can only be determined reliably if stray light does not constitute a significant part of the
measured signal. The allowable (absolute) deviation is larger for higher luminance values.

61747-6 © IEC:2004 – 37 –
Note that cross-talk may adversely affect the values of CR and CR , which is not the case
lod dol
in the determination of CR . In addition, extra straylight can be generated by the DUT duri
...