IEC 61747-30-5:2019

IEC 61747-30-5 ®
Edition 1.0 2019-01
INTERNATIONAL
STANDARD
colour
inside
Liquid crystal display devices –
Part 30-5: Optical measuring methods of transmissive transparent LCD modules
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IEC 61747-30-5 ®
Edition 1.0 2019-01
INTERNATIONAL
STANDARD
colour
inside
Liquid crystal display devices –

Part 30-5: Optical measuring methods of transmissive transparent LCD modules

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 31.120 ISBN 978-2-8322-6420-1

– 2 – IEC 61747-30-5:2019  IEC 2019
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms, definitions, symbols and units . 6
4 Measurement conditions . 7
4.1 Standard measurement environmental conditions . 7
4.2 Standard measurement darkroom conditions. 8
4.3 Standard measurement locations . 8
5 Measurement methods of on-screen properties . 8
5.1 Measurement equipment and its setup . 8
5.2 Measurement methods . 9
6 Measurement methods of through-screen properties . 10
6.1 Luminous transmittance and its uniformity . 10
6.1.1 Purpose . 10
6.1.2 Measurement conditions . 10
6.1.3 Measurement methods . 10
6.2 Transmitted haze . 11
6.2.1 Purpose . 11
6.2.2 Measurement conditions . 11
6.2.3 Test apparatus . 11
6.2.4 Procedure . 13
6.2.5 Results . 14
6.2.6 Reporting . 14
6.3 Colour shift . 14
6.3.1 Purpose . 14
6.3.2 Measurement conditions . 14
6.3.3 Test apparatus . 14
6.3.4 Procedure . 15
6.3.5 Reporting . 15
6.4 Contrast ratio offset . 16
6.4.1 Purpose . 16
6.4.2 Measurement conditions . 16
6.4.3 Test apparatus . 16
6.4.4 Procedure . 16
6.4.5 Reporting . 17
6.5 Sharpness . 17
6.5.1 Purpose . 17
6.5.2 Measuring conditions . 17
6.5.3 Test apparatus . 17
6.5.4 Procedure . 18
6.5.5 Results . 18
6.5.6 Reporting . 20
6.6 MTF and Michelson contrast ratio . 20
6.6.1 Purpose . 20
6.6.2 Measurement conditions . 20
6.6.3 Measurement methods . 20

6.6.4 Reporting . 22
7 Contrast ratio and colour coordinates with the incident illumination originating
from objects behind the screen . 22
7.1 Purpose . 22
7.2 Measurement method with white light source . 24
7.2.1 General . 24
7.2.2 Measurement conditions . 24
7.2.3 Measurement method . 24
7.3 Measurement method with collimated or directional light source . 25
7.3.1 Purpose . 25
7.3.2 Measurement conditions . 25
7.3.3 Measurement method background . 26
7.3.4 Measurement method . 26
Bibliography . 27

Figure 1 – Measurement points . 8
Figure 2 – Measurement equipment and its configuration . 9
Figure 3 – Measurement configuration with light source . 10
Figure 4 – Schematic arrangement of the apparatus (TOP view) . 13
Figure 5 – Measurement system and its configuration . 15
Figure 6 – Reference object and its configuration . 16
Figure 7 – Example reference object and its configuration . 18
Figure 8 – Luminance curve of reference object . 19
Figure 9 – Definition of test parameters . 20
Figure 10 – Reference object and its configuration. 21
Figure 11 – Relationship between stripe frequency and MTF . 22
Figure 12 – Geometry of the transparent display and the bright background object . 23
Figure 13 – Case with bright backgrounds . 23
Figure 14 – Measurement configuration for transparent display with background object . 25

Table 1 – Measurements . 13
Table 2 – Measurement results . 16
Table 3 – Data summary for contrast offset . 17
Table 4 – Example of reported specification of two-dimensional LMD . 18

– 4 – IEC 61747-30-5:2019  IEC 2019
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LIQUID CRYSTAL DISPLAY DEVICES –

Part 30-5: Optical measuring methods of transmissive
transparent LCD modules
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
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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 61747-30-5 has been prepared by IEC technical committee 110:
Electronic display devices.
The text of this International Standard is based on the following documents:
FDIS Report on voting
110/1047/FDIS 110/1070/RVD
Full information on the voting for the approval of this International Standard 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 the parts in the IEC 61747 series, under the general title Liquid crystal display
devices, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document 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.
– 6 – IEC 61747-30-5:2019  IEC 2019
LIQUID CRYSTAL DISPLAY DEVICES –

Part 30-5: Optical measuring methods of transmissive
transparent LCD modules
1 Scope
This part of IEC 61747 specifies the standard measurement conditions and measuring
methods for determining the optical properties of transparent liquid crystal display modules
which operate in a transmissive mode.
More specifically, this document focuses on three particular aspects of the transparent
properties, i.e. transmittance, haze, and image distortion.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements 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.
IEC 61747-1-2, Liquid crystal display devices – Part 1-2: Generic – Terminology and letter
symbols
IEC 61747-30-1, Liquid crystal display devices – Part 30-1: Measuring methods for liquid
crystal display modules – Transmissive type
ISO 11664-1, Colorimetry – Part 1: CIE standard colorimetric observers
ISO 11664-2, Colorimetry – Part 2: CIE standard illuminants
ISO 14782, Plastics: Determination of haze for transparent materials
3 Terms, definitions, symbols and units
For the purposes of this document, the terms, definitions, symbols and units given in
IEC 61747-1-2, as well as the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
transparent liquid crystal display module
direct-view liquid crystal display module that can show the information on the screen and
allow real objects to be viewed through the screen
3.2
on-screen property
visual properties when the focus of the viewer is on the display screen

3.3
through-screen property
visual properties when the focus of the viewer is on the object behind the display screen
3.4
transmittance
ratio of the transmitted radiant or luminous flux to the incident flux in the given conditions
[SOURCE: IEC 60050-845:1987, 845-04-59, modified – The text in brackets after the term has
been omitted.]
3.5
transmitted haze
percentage of transmitted light that is scattered more than 2,5° from the direction of the
incident beam relative to the total transmitted light
3.6
sharpness
apparent blurring of the border between two adjacent areas with different brightness
3.7
colour shift
change in chromaticity of an object when viewed through transparent liquid crystal display
devices
3.8
contrast ratio offset
change in contrast ratio of the reference object when viewed through transparent liquid crystal
display devices
3.9
MTF
modulation transfer function
ratio of the final to the initial signal amplitude as a function of the spatial frequency of the
initial signal
[SOURCE: IEC 60050-881:1983, 881-04-65, modified – The abbreviated term "MTF" has been
added, and the Note to entry, omitted.]
4 Measurement conditions
4.1 Standard measurement environmental conditions
Measurements shall be carried out under standard environmental conditions:
• temperature: 25 °C ± 3 °C;
• relative humidity: 25 % RH to 85 % RH;
• atmospheric pressure: 86 kPa to 106 kPa.
When different environmental conditions are used, they shall be noted in the measurement
report.
– 8 – IEC 61747-30-5:2019  IEC 2019
4.2 Standard measurement darkroom conditions
The luminance contribution from unwanted background illumination reflected off the test
display shall be less than 1/20 the display's black state luminance. If this condition is not
satisfied, then background subtraction is required and it shall be noted in the test report. In
addition, if the sensitivity of the light measure device (LMD) is inadequate to measure at these
low levels, then the lower limit of the LMD shall be noted in the test report.
4.3 Standard measurement locations
Luminance, radiance distribution and/or tristimulus values may be measured at several
specified positions on the surface of the device under test (DUT), see Figure 1. Unless
otherwise specified, measurements are carried out in the centre of each circle. Care shall be
taken to ensure that the measuring spots on the display do not overlap.
Any deviation from the above-described standard positions shall be added to the detail
specification.
P P P
P P
23 24 10
9 11
P P P P
P
22 8 2
1 12
P P P P P
21 7 0 3 13
P P P P
P
20 6 5 4
P P P
P P
19 17 16
18 15
(1/10)V
(3/10)H
(1/10)H
(5/10)H
IEC
Figure 1 – Measurement points
5 Measurement methods of on-screen properties
5.1 Measurement equipment and its setup
Three different instruments may be applied to measure the light transmitted and/or reflected
by the DUT: a luminance meter, colorimeter or spectroradiometer. The optical system is
shown schematically in Figure 2 and will allow for measurement of well-defined spot sizes
(measurement field) on the DUT.
(5/10)V
(3/10)V
IEC
Figure 2 – Measurement equipment and its configuration
When the measure matrix displays, the above-mentioned meters should be set to a circular or
rectangular field of view that includes more than 500 pixels on the display, and measured
perpendicular to the screen surface (the standard measurement direction). Total angular
aperture of detection by these meters: angular aperture shall be less than 5° and the
measurement field angle should be less than 2° (see Figure 2). This can be obtained, for
example, by having a measuring distance of 50 cm between the meters and the display area
centre (recommended) (see Figure 2). If measuring segmented displays, the measurement
field should be located completely inside a single segment, and should not include any of its
surroundings.
For DUTs not equipped with their own source of illumination, an external backlight source
should be used to provide uniform illumination to the DUT.
The isolated directed light source is the preferred directed source. If the display exhibits
strong asymmetric scatter, then integrating spheres with the sample port close to the screen
shall be used (e.g., Figure 3).
Measure the following parameters of the light source:
a) spectrum of emission;
b) luminance, L;
c) temporal stability of the luminance, L(t);
d) luminance distribution with viewing angle, L(θ, ϕ).
Unless otherwise specified, it is recommended to use a spectrally smooth broadband light
source that approximates the spectrum of CIE-D .
5.2 Measurement methods
For on-screen properties, such as luminance, chromaticity, viewing angle, reflection and so on,
the test methods specified in IEC 61747-30-1 shall apply.
The choice of the appropriate tests depends on the application of the display modules. The
relevant specification shall state which tests are applicable.

– 10 – IEC 61747-30-5:2019  IEC 2019
6 Measurement methods of through-screen properties
6.1 Luminous transmittance and its uniformity
6.1.1 Purpose
The purpose of this method is to determine the transmittance and the uniformity of
transmittance of a transparent LCD panel under test.
6.1.2 Measurement conditions
For this measurement, the following conditions shall be applied.
a) Apparatus: an integrating sphere with standard light source; a light measurement device
that can measure the luminance; driving power source, and driving signal equipment. The
measurement geometry is as shown in Figure 3.
b) Standard environmental conditions for measurements: darkroom conditions; standard
setup conditions.
c) The distance between the light measurement device and integrating sphere should be
consistent during the test, for example, set at 50 cm.
IEC
Figure 3 – Measurement configuration with light source
6.1.3 Measurement methods
The transmittance of the liquid crystal display device is obtained by comparing the luminous
value of the DUT to the light source. It shall be ensured that all conditions remain constant
during the measurement of both luminance values (temperature, illumination, etc.).
Proceed as follows:
a) allow the apparatus sufficient time to reach thermal equilibrium before making any
measurements;
b) measure the luminance of the light source L at the centre position P ;
1 0
c) mount the transparent LCD panel in front of the light source;
d) apply a full-screen white signal at a 100 % grey level;
e) measure the transmitted luminance L at position P .
2 0
Calculate the luminous transmittance, τ, as a percentage, using Equation (1):

L
τ= (1)
L
To achieve transmittance uniformity, proceed as follows.
1) Measure the luminous transmittance at specific points, P. Either 5 or 9 measurement
i
, P , P , P , and P . For 9 points, use P , P ,
points shall be used. For 5 points, use P
0 11 15 19 23 0 9
P , P , P , P , P , P , and P .
11 13 15 17 19 21 23
2) The average transmittance is as per Equation (2) or (3):
τ ()τ+τ+++τττ (2)
av 0 11 15 19 23
or
τ ()τ+τ+τ+++ττ τττ +++τ
(3)
av 0 9 11 13 15 17 19 21 23
3) The transmittance non-uniformity (TNU) is calculated from the individual transmittance τ
i
in accordance with Equation (4):
and the average luminance τ
av


ττ−
av i
TNU max ×100 %
 (4)

τ

av


The measuring distance and other factors that can affect the measurement result should be
reported.
6.2 Transmitted haze
6.2.1 Purpose
The purpose of this method is to evaluate the transmitted haze of a transparent LCD module.
ISO 14782 shall be applied for this test item.
6.2.2 Measurement conditions
Standard measuring is implemented under the standard environmental conditions.
6.2.3 Test apparatus
Proceed as follows.
a) The apparatus shall consist of a stabilized light source, an associated optical system, an
integrating sphere with ports, and a photometer comprising a photodetector, signal
processor and display unit or recorder (see Figure 4).
b) The light source and the photometer shall be used in conjunction with a filter to provide an
output corresponding to the photopic standard luminous efficiency V(λ) (as defined in
IEC 60050-845:1987, 845-01-57). V(λ) is identical to the colour-matching function y (λ);
reference shall be made to ISO 11664-1 under CIE standard illuminant D as specified in
ISO 11664-2. By measuring the spectral power distribution of the light source in advance
using the detector, the measured spectral information is used to determine the equivalent
result for a D65 light source. The output of the photodetector shall be proportional to the
incident flux, to within 1 % of the incident flux, over the range used. The spectral and
photometric characteristics of the light source and photometer shall be kept constant
during measurements.
=
=
=
– 12 – IEC 61747-30-5:2019  IEC 2019
c) The light source and its associated optical system shall produce a parallel light beam, no
ray of which shall make an angle of more than 0,05 rad (3°) with the beam axis. This
beam shall not be vignetted at either port of the integrating sphere.
d) The design of the instrument shall be such that the reading is zero in the absence of the
light beam.
e) The integrating sphere used to collect the transmitted light may be of any diameter (but
preferably no less than 150 mm in order to be able to accommodate large specimens), as
long as the total port area does not exceed 3,0 % of the internal reflecting area of the
sphere.
f) The integrating sphere shall have an entrance port, an exit port, a compensation port and
a photodetector port (see Figure 4). The entrance and exit ports shall be centred on the
same great circle of the sphere, and there shall be an angle of (3,14 ± 0,03), rad
(180° ± 2°) between the centres of the ports. The exit port shall subtend an angle of
(0,140 ± 0,002), rad (8° ± 0,1°) at the centre of the entrance port. The exit and
compensation ports shall be the same size. The entrance and compensation ports and the
photodetector shall not lie on the same great circle of the sphere. The compensation port
shall be positioned at an angle of less than 1,57 rad (90°) from the entrance port. The
compensation port is used to compensate for changes in the efficiency of the integrating
sphere, which depends on the area of the inner surface, the number of ports and the way
in which they are covered.
g) When the beam is unobstructed by a transparent LCD module, its cross section at the exit
port s
...