IEC 62341-6-4:2017

IEC 62341-6-4 ®
Edition 1.0 2017-05
INTERNATIONAL
STANDARD
colour
inside
Organic light emitting diode (OLED) displays –
Part 6-4: Measuring methods of transparent properties
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 Fax: +41 22 919 03 00
CH-1211 Geneva 20 info@iec.ch
Switzerland 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 corrigenda or an amendment might have been published.

IEC Catalogue - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
The stand-alone application for consulting the entire The world's leading online dictionary of electronic and
bibliographical information on IEC International Standards, electrical terms containing 20 000 terms and definitions in
Technical Specifications, Technical Reports and other English and French, with equivalent terms in 16 additional
documents. Available for PC, Mac OS, Android Tablets and languages. Also known as the International Electrotechnical
iPad. Vocabulary (IEV) online.

IEC publications search - www.iec.ch/searchpub IEC Glossary - std.iec.ch/glossary
The advanced search enables to find IEC publications by a 65 000 electrotechnical terminology entries in English and
variety of criteria (reference number, text, technical French extracted from the Terms and Definitions clause of
committee,…). It also gives information on projects, replaced IEC publications issued since 2002. Some entries have been
and withdrawn publications. collected from earlier publications of IEC TC 37, 77, 86 and

CISPR.
IEC Just Published - webstore.iec.ch/justpublished

Stay up to date on all new IEC publications. Just Published IEC Customer Service Centre - webstore.iec.ch/csc
details all new publications released. Available online and If you wish to give us your feedback on this publication or
also once a month by email. need further assistance, please contact the Customer Service
Centre: csc@iec.ch.
IEC 62341-6-4 ®
Edition 1.0 2017-05
INTERNATIONAL
STANDARD
colour
inside
Organic light emitting diode (OLED) displays –

Part 6-4: Measuring methods of transparent properties

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 31.260 ISBN 978-2-8322-4297-1

– 2 – IEC 62341-6-4:2017  IEC 2017
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Measuring conditions . 7
4.1 Standard measuring environmental conditions . 7
4.2 Standard lighting conditions . 7
4.2.1 Darkroom conditions . 7
4.2.2 Ambient illumination conditions . 7
4.2.3 Ambient illumination spectra . 8
4.3 Standard setup conditions . 8
4.3.1 Starting conditions of measurements . 8
4.3.2 Conditions of measuring equipment . 9
5 Measuring methods of transparent properties . 10
5.1 Measuring methods of transmission performance . 10
5.1.1 Hemispherical transmittance factor with specular included . 10
5.1.2 Transmitted haze under hemispherical illumination . 12
5.1.3 Directional transmittance factor . 14
5.1.4 Measurement method of purity . 16
5.1.5 Colour variation caused by a transparent display . 19
5.2 Measuring methods of on-screen performance in a darkroom. 20
5.2.1 Luminance and its uniformity . 20
5.2.2 Chromaticity and colour non-uniformity . 23
5.2.3 Darkroom contrast ratio . 24
5.2.4 Grey scale and gamma characteristics . 25
5.2.5 Colour gamut . 27
5.2.6 Directional optical characteristics . 29
6 Measuring methods of reflection properties . 30
6.1 Hemispherical reflectance factor with specular included . 30
6.1.1 Purpose . 30
6.1.2 Measuring conditions . 30
6.1.3 Measuring method . 30
6.2 Directional reflectance factor . 31
6.2.1 Purpose . 31
6.2.2 Measuring conditions . 31
6.2.3 Measuring method . 31
7 Optical on-screen performance under ambient illumination . 31
7.1 Ambient contrast ratio . 31
7.1.1 Purpose . 31
7.1.2 Measuring conditions . 32
7.1.3 Measuring method . 32
7.2 Display ambient colour measurement . 33
7.2.1 Purpose . 33
7.2.2 Measuring conditions . 33
7.2.3 Measuring method . 34

Annex A (normative) Alternative method for measuring the hemispherical
transmittance factor of a transparent OLED display . 36
A.1 Purpose . 36
A.2 Measuring conditions . 36
A.3 Measuring the transmittance . 36
Bibliography . 39

Figure 1 – Layout diagram of measurement setup . 9
Figure 2 – Side view of measuring concept for the hemispherical transmittance factor
measurement with specular included or excluded . 12
Figure 3 – Schematic arrangement of haze measurement . 14
Figure 4 – Side view of measuring concept for the hemispherical transmittance factor
measurement with specular included or excluded . 16
Figure 5 – Measuring configuration for purity measurement . 18
Figure 6 – Test patterns for purity measurement . 18
Figure 7 – Test pattern for 4 % window luminance . 21
Figure 8 – Example of luminance loading measurement . 22
Figure 9 – Measurement locations . 23
Figure 10 – Measuring patterns for gamma measurement . 26
Figure A.1 – Measurement geometry using a sampling sphere . 37

Table 1 – Standard ambient conditions . 8
Table 2 –Measuring conditions of the ports . 14
Table 3 – Measured example for purity . 19
Table 4 – Working example for colour variation index . 20
Table 5 – Worked example for luminance loading . 22
Table 6 – Example of luminance non-uniformity . 23
Table 7 – Example of colour uniformity measurement . 24
Table 8 – Example of gamma measurement . 26
Table 9 – Reference areas for the colour reproduction range . 28
Table 10 – Example of measurement for the colour gamut variation ratio . 28
Table 11 – Example of measurement for the directional electro-optical characteristic . 30

– 4 – IEC 62341-6-4:2017  IEC 2017
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ORGANIC LIGHT EMITTING DIODE (OLED) DISPLAYS –

Part 6-4: Measuring methods of transparent properties

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 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
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 62341-6-4 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
110/843/FDIS 110/866/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 parts in the IEC 62341 series, published under the general title Organic light
emitting diode (OLED) displays, 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 62341-6-4:2017  IEC 2017
ORGANIC LIGHT EMITTING DIODE (OLED) DISPLAYS –

Part 6-4: Measuring methods of transparent properties

1 Scope
This part of IEC 62341 specifies the standard measurement conditions and measuring
methods for determining the optical performance of transparent properties of organic light
emitting diode (OLED) display panels and modules. This document includes the display
performance under darkroom conditions, and front and back illumination.
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 62341-1-2, Organic light emitting diode (OLED) displays – Part 1-2: Terminology and
letter symbols
IEC 62341-6-1, Organic light emitting diode (OLED) displays – Part 6-1: Measuring methods
of optical and electro-optical parameters
IEC 62341-6-2, Organic light emitting diode (OLED) displays – Part 6-2: Measuring methods
of visual quality and ambient performance
ISO 9241-307, Ergonomics of human-system interaction – Part 307: Analysis and compliance
test methods for electronic visual displays
ISO 11664-2, Colorimetry – Part 2: CIE standard illuminants
CIE 15-2004, Colorimetry
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 62341-1-2 and 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
transmittance factor
ratio of the radiant or luminous flux transmitted in the direction delimited by the given solid
angle cone to that transmitted in the same direction and solid angle cone by a perfect
transmitting diffuser identically irradiated or illuminated
Note 1 to entry: When the term transmittance factor is used in this document, it refers to the photopically-
weighted luminous flux.
3.2
spectral transmittance factor
ratio of the spectral radiant flux transmitted in the direction delimited by the given solid angle
cone to that transmitted in the same direction by a perfect transmitting diffuser identically
irradiated
3.3
transmitted haze
percentage of transmitted luminance, passing through a specimen, which deviates from the
incident light by no more than 0,044 rad (2,5°) by forward scattering
3.4
purity
ratio of the luminance measured in the 0,2° region to the luminance of the total transmitted
light
Note 1 to entry: The purity is defined as how clearly the see-through image could be seen. The purity is derived
from the measurement of distorted light due to diffraction or refraction.
3.5
on-screen performance
optical performance that can be measured on the transparent screen when viewing an image
on the screen
4 Measuring conditions
4.1 Standard measuring environmental conditions
Measurements shall be carried out under the standard environmental conditions:
Temperature: 25 ºC ± 3 ºC
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.
4.2 Standard lighting conditions
4.2.1 Darkroom conditions
The luminance contribution from the background illumination reflected off and/or transmitted
through the test display shall be less than 0,01 cd/m or 1/20 of the display’s black state
luminance, whichever is lower. If these conditions are not satisfied, then background
subtraction is required and it shall be noted in the report. In addition, if the sensitivity of the
light measuring device (LMD) is inadequate to measure at these low levels, then the lower
limit of the LMD shall be noted in the measurement report.
4.2.2 Ambient illumination conditions
Ambient lighting conditions can make a large impact on the performance of a transparent
display. For observers who will watch a transparent display, various ambient conditions shall
be suggested based on previous research. Table 1 shows the standard indoor and daylight
ambient illumination conditions.

– 8 – IEC 62341-6-4:2017  IEC 2017
Uniform hemispherical diffuse illumination will be used to simulate the background lighting in
a room or the hemispherical skylight incident on the display, with sun occluded. The detail
information to simulate those ambient conditions is described in IEC 62341-6-2 and IDMS [1] .
Table 1 – Standard ambient conditions
Design screen Recommended
Indoor and daylight illumination environment
illuminance illumination geometry
(mostly) General building areas (ISO 9241-307) 60 % hemispherical,
Up to 200 lx
40 % directional at 45°
(mostly) General machine work, rough assembly work, 60 % hemispherical,
Up to 300 lx
(general) museum (ISO 9241-307), office environment [8]
40 % directional at 45°
Medium assembly and decorative work, simple inspection, 60 % hemispherical,
Up to 500 lx counters, libraries, (mostly) educational areas, control rooms
40 % directional at 45°
(ISO 9241-307)
Fine work, technical drawing (ISO 9241-307) 60 % hemispherical,
Up to 750 lx
40 % directional at 45°
Precision work, quality control, inspection, medical 60 % hemispherical,
Up to 1 000 lx
examination and treatment (ISO 9241-307)
40 % directional at 45°
High precision work (ISO 9241-307) 60 % hemispherical,
Up to 1 500 lx
40 % directional at 45°
Special workplaces in the medical area (ISO 9241-307) 60 % hemispherical,
> 1 500 lx
40 % directional at 45°
The daylight contrast ratio and colour shall be calculated
15 000 lx hemispherical,
using a combination of hemispherical diffuse illumination (with
80 000 lx
specular included) and directional illumination incident on a
65 000 lx directional at 45°
display surface in a vertical orientation [8][9]

4.2.3 Ambient illumination spectra
The ambient performance of the display can be significantly impacted by the spectral
distribution of the illumination source. Unless it is specified otherwise, the source illumination
shall closely approximate CIE Illuminant D65 (see CIE 15). The source illumination used for
measuring the display reflection and transmission properties shall have a spectrally smooth
and broadband emission. Spectral reflection and transmission measurements can then be
used to predict the ambient display performance for any desired illumination spectra.
When evaluating the display’s ambient indoor performance, it is recommended to use the
same spectral distribution for the hemispherical and directional source illumination. Light
source spectra approximating CIE Illuminant A, Illuminant D50, and Illuminant D65 are
recommended for indoor applications. For simulating outdoor applications, Illuminant D50 is
recommended for the directional illumination, and Illuminant D75 is recommended for
hemispherical illumination.
4.3 Standard setup conditions
4.3.1 Starting conditions of measurements
Standard setup conditions are given below. Measurements shall be started after the
transparent OLED display and measuring instruments achieve stability. Sufficient warm-up
time has to be allowed for the transparent OLED display panels and modules to reach a
___________
Numbers in square brackets refer to the Bibliography.

luminance stability level of less than ±5 % over the entire measurement for a given display
image.
4.3.2 Conditions of measuring equipment
The general conditions of this measurement shall be as follows.
1) The standard measurement setup is shown in Figure 1. The LMD shall be a luminance
meter, colourimeter, or a spectroradiometer capable of measuring spectral radiance over
at least the 380 nm to 780 nm wavelength range, with a maximum bandwidth of 10 nm for
smooth broadband spectra. For light sources that have sharp spectral features, like LEDs
and fluorescent lamps, the spectroradiometer’s maximum bandwidth shall be < 5 nm. The
spectral bandwidth of the spectroradiometer shall be an integer multiple of the sampling
interval. For example, a 5 nm sampling interval can be used for a 5 nm or 10 nm
bandwidth. Care shall be taken to ensure that the device has enough sensitivity and
dynamic range to perform the required task.
2) The light measuring device shall be focused on the image plane of the transparent display
for on-screen performance and on the image plane of the background for transmission
performance. The LMD will be aligned perpendicularly to its surface, unless stated
otherwise.
3) The relative uncertainty and repeatability of all the measuring devices shall be maintained
by following the instrument supplier’s recommended calibration schedule.
Angular field
of view
Angular
aperture
Measurement
field
Measurement-field angle
IEC
Figure 1 – Layout diagram of measurement setup
4) The LMD integration time shall be an integer number of frame periods, synchronized to
the frame rate, or the integration time shall be greater than two hundred frame periods.
5) When measuring matrix displays, the light measuring devices shall be set to a
measurement field that includes more than 500 pixels. If smaller measurement areas are
necessary, equivalence to 500 pixels shall be confirmed.
6) The angular aperture shall be less than or equal to 5°, and measurement field angle shall
be less than or equal to 2° (see Figure 1). The measuring distance and the measurement-
field angle may be adjusted to achieve a measurement field greater than 500 pixels if
setting the above measurement-field angle is difficult.
7) Display modules shall be operated at their design field frequency. When using separate
driving signal equipment to operate a panel, the drive conditions shall be noted in the
performance report.
Any deviations from these conditions shall be noted in the performance report.
Field of view
Acceptance area
– 10 – IEC 62341-6-4:2017  IEC 2017
5 Measuring methods of transparent properties
5.1 Measuring methods of transmission performance
5.1.1 Hemispherical transmittance factor with specular included
5.1.1.1 Purpose
The purpose of this method is to measure the transmitted light, including the specular component,
through a transparent OLED display.
5.1.1.2 Measuring conditions
For this measurement, the following conditions shall be applied.
a) Apparatus:
1) light measuring device that can measure luminance or spectral radiance;
2) driving power source;
3) driving signal equipment;
4) integrating sphere with ports and a stabilized light source (see Figure 2), which shall
be as follows:
i) The light source in the integrating sphere should have a smooth broadband
spectrum approximating CIE standard Illuminant D65, as specified in ISO 11664-2.
The integrating sphere should have a photopic optical detector which monitors the
relative luminance level m inside the sphere. The monitor shall be fitted with
baffles to prevent light from the light source or the sample port from falling on it
directly. The spectral characteristics of the light source shall be kept constant
during measurements on a transparent OLED display. The measurement
conditions shall be such that the transparent OLED display temperature does not
increase while measurements are made.
ii) The integrating sphere may be of any diameter as long as the total port area does
not exceed 4,0 % of the internal area of the sphere. It is recommended that the
diameter of the integrating sphere is not less than 150 mm so that specimens of a
reasonable size can be used. When diameter of the integrating sphere is 150 mm
and the diameters of the sample, compensation and light trap ports are 30 mm, the
ratio of the total port area to the internal area of the sphere is 3,0 %. For specular
included measurements, a port plug or diffuse white standard with similar
reflectance to the inner wall can be used to fill the port. A sphere geometry may
also be used instead for the configuration illustrated in Figure 2 (see Annex A). If
the integrating sphere does not have a compensation port, and placing the OLED
display at the sample port significantly changes the spectral distribution of the light
in the sphere, the alternate sphere method in Annex A shall be used. In addition, if
it is necessary to measure the hemispherical transmittance factor with the OLED
display on, then the alternate sphere method shall be used.
iii) It is recommended to use a sample port between 30 mm to 75 mm. If a
compensation port is used, the sample and compensation ports of the integrating
sphere shall be circular and of the same size. The compensation port shall be
positioned at an angle of less than 1,57 rad (90°) from the sample port. The
sample port, compensation port and light trap port shall not lie on the great circle
of the sphere. The ports shall be designed in such a way that samples placed at
the port will lie at nearly the same surface as the inner sphere wall.
iv) The surfaces of the interior of the integrating sphere and the baffles shall be of
substantially equal luminous reflectance which shall be 90 % or more and shall not
vary by more than ±3 %. The sphere wall reflectance can be determined relative to
a known reflection standard using the method described in Annex A.

v) Using this instrument, the repeatability standard deviation shall be 0,2 % or less.
The within-laboratory reproducibility over long time intervals shall not exceed the
repeatability by a factor of more than 3.
vi) The flat sample shall be held against the sample port so that the normal of the
o
sample is within 2 of the normal of the sample port. The sphere interior should
provide uniform illumination on the screen, with the screen receiving a constant
luminance over its hemispherical inclination angles. This criterion is often satisfied
when the sphere’s internal light source dominates the illuminance inside the
sphere compared to any sample contribution.
vii) The LMD is aligned normal to the centre of the sample port at an approximate
distance of 0,5 m. The measurement field shall be focused on the sample port
plane.
b) Standard measuring environmental conditions:
1) darkroom conditions;
2) standard setup conditions.
5.1.1.3 Measuring method
The method is similar to ASTM D1003 [2], and analogous to ISO 13468-1 [3]. This method
assumes that the transmission properties of the transparent OLED display are not affected by
the illumination level on the display.
1) If the integrating sphere has a light trap port, place a port plug or diffuse white standard at
the port. Turn on the integrating sphere light source and allow the light source and LMD to
stabilize. The measurement configuration in Figure 2 shall be set up in a dark room, and
ingress of external light into the integrating sphere shall be prevented.
2) If the integrating sphere has a compensation port, place the backside of the transparent
OLED display against that port. The display is turned off.
3) Measure the luminance L or spectral radiance at the sample port, and record the
ref
monitor detector value m .
ref
4) Place the backside of the transparent OLED display against the sample port. If the
integrating sphere has a compensation port, place a light trap at that port. Measure the
transmitted luminance (or spectral radiance) at the sample port L , and record the
di/0
monitor detector value m .
di/0
5) Calculate the luminous hemispherical transmittance factor with specular included T
di/0
using Formula (1):
L m
di/0 di/0
T = ⋅
(1)
di/0
L m
ref ref
6) Repeat the readings for L , m , L , and m , making additional readings with the
ref ref di/0 di/0
specimen in positions selected to determine uniformity.
7) Carry out the procedure three times, and use the average of the three calculated results
as the luminous hemispherical transmittance factor value.
8) All details are required to be recorded for identification of the test specimens and the
source of the specimens (type of light source used, information of transparent OLED
display).
If the transmission properties of the transparent OLED display are different in the off from the
on state, then the alternate sphere method in Annex A shall be used.

– 12 – IEC 62341-6-4:2017  IEC 2017
Optical
monitor
Light-trap
Sample
port
Black
Detector
glass
"Exit port"
(sample port)
Compensation port
White
standard
IEC
Figure 2 – Side view of measuring concept for the hemispherical transmittance
factor measurement with specular included or excluded
5.1.2 Transmitted haze under hemispherical illumination
5.1.2.1 Purpose
The purpose of this method is to measure the amount of haze transmitted to the viewer from a
transparent OLED display back-illuminated with hemispherical illumination.
5.1.2.2 Measuring conditions
For this measurement, the following conditions shall be applied.
a) Apparatus:
1) light measuring device that can measure luminance or spectral radiance;
2) driving power source;
3) driving signal equipment;
4) integrating sphere with ports and a stabilized light source (see Figure 2), which shall
be as follows:
i) The light source in the integrating sphere should have a smooth broadband
spectrum approximating CIE standard Illuminant D65, as specified in ISO 11664-2.
The integrating sphere should have a photopic optical detector which monitors the
relative luminance level m inside the sphere. The monitor shall be fitted with
baffles to prevent light from the light source or the sample port from falling on it
directly. The spectral characteristics of the light source shall be kept constant
during measurements on a transparent OLED display. The measurement
conditions shall be such that the transparent OLED display temperature does not
increase while measurements are made.
ii) The total port area of the integrating sphere should not exceed 4,0 % of the
internal area of the sphere. It is recommended that the diameter of the integrating
sphere is not less than 150 mm so that specimens of a reasonable size can be
used. When the diameter of the integrating sphere is 150 mm and the diameters of
the sample, compensation and light trap ports are 30 mm, the ratio of the total port
area to the internal area of the sphere is 3,0 %. If the integrating sphere does not
have a compensation port, and placing the OLED display at the sample port does
not significantly change the spectral distribution of the light in the sphere, the
monitor detector shall be used to compensate for change in the sphere illuminance
due to the presence of the display at the sample port.
iii) A detailed illustration of the specular excluded and transmitted haze geometry is
given in Figure 3.
iv) The sample port and light trap port shall be centred on the same optical axis as
the LMD. The diameter of the sphere z , and the light trap port diameter d shall
s LT
be sized such that the opening of the light trap port shall subtend θ = 8° from the
LT
centre of the sample port. The LMD shall be positioned a distance z away from
LMD
the sphere, producing a measurement field of diameter d focused at the sample
mf
port, where d = z d /(z +z ) and d is the projected measurement field
mf d pmf LMD s pmf
diameter at the light trap port. The LMD and sphere shall be set up such that the
angular gap (annulus) ξ = θ /2 - arctan[d /(2 z )] between the projected
LT pmf s
measurement field diameter d and the light trap port diameter shall give
pmf
ξ = 1,3°. When the above requirements are satisfied, the maximum angle φ that
any measured light ray can have relative to the normal is less than 3°. Ensure that
the LMD measurement field is contained within the image of the light trap port area.
b) Standard measuring environmental conditions:
1) darkroom conditions;
2) standard set-up conditions.
5.1.2.3 Measuring method
The method is similar to ASTM D1003 [2] and analogous to ISO 14782 [4].
NOTE 1 This method assumes that the transmission properties of the transparent OLED display are not affected
by the illumination level on the display.
NOTE 2 This method also assumes that the transmission properties are invariant to the rendered colour on the
display, and allows the transmission properties to be measured with the display turned off.
1) Place a port plug or diffuse white standard at the light trap port. Turn on the integrating
sphere light source and allow the light source and LMD to stabilize. The measurement
configuration in Figure 2 shall be set up in a dark room, and ingress of external light into
the integrating sphere shall be prevented.
2) If the integrating sphere has a compensation port, place the backside of the transparent
OLED display against that port. The display is turned off.
3) Align the LMD normal to the sample port and focus the measurement field at the centre of
the port. Measure the luminance L at the centre of the sample port, and record the
monitor detector value m .
4) Place the backside of the transparent OLED against the sample port. If the integrating
sphere has a compensation port, place a light trap at that port.
5) Measure the transmitted luminance L through the display at the centre of the sample port,
and record the monitor detector value m .
6) Replace the port plug or diffuse white standard at the light trap port with a light trap. If the
integrating sphere has a compensation port, place the port plug or the diffuse white
standard at that port. Measure the transmitted luminance L through the display at the
centre of the sample port, and record the monitor detector value m .
7) Remove the transparent OLED display from the sample port. Measure the luminance L at
the centre of the sample port, and record the monitor detector value m .
8) The luminous hemispherical transmittance factor with specular excluded T is given as:
de/0
 
L L L m
m
1 4 3 2 1
 
T = −
(2)
Q,de/0
L m L L m
 
4 1 3 2 

where each variable is associated with the measurement configuration list in Table 2.
9) The percent luminous hemispherical transmitted haze H is determined by:
de/0
– 14 – IEC 62341-6-4:2017  IEC 2017
m m L
 
L
2 4 1 3
H =100%× × − ×
 
(3)
de/0
m L m L
 4 1 3 1 
 
Table 2 –Measuring conditions of the ports
Measured Sample port Light trap port Compensation port
luminance
L White reference Display sample
L Display sample White reference Light trap
L Light trap White reference
L Display sample Light trap White reference
10) All details are required to be recorded for identification of the test specimens and the
source of the specimens, such as type of light source used, information on transparent
OLED display.
Sphere
Sample
LMD
port
Light trap
θ
LT ξ
port
φ
d
sp
Z Z
S LMD
IEC
Figure 3 – Schematic arrangement of haze measurement
5.1.3 Directional transmittance factor
5.1.3.1 Purpose
The purpose of this method is to measure the transmittance factor of a transparent OLED display
that is back-illuminated with a directional light source.
5.1.3.2 Measuring conditions
For this measurement, the following conditions shall be applied.
a) Apparatus:
1) light measuring device that can measure luminance or spectral radiance;
2) driving power source;
3) driving signal equipment;
4) white reflectance standard;
5) ring light with a stabilized light source, which shall be as follows:
i) Directional illumination shall be simulated by a ring light (Figure 4) centred about
the display normal. A fibre optic ring light designed for a working distance that
approximates 45° light inclination at the centre of the measurement position is
d
mf
recommended. The illumination within the measuring field area on the display shall
be uniform < 5 %.
ii) For the ring light, the source should have an emitter angular subtense of
approximately 0,5°. The ring light emitting plane shall be co-planar with the display
surface and centred about the measurement area. The central clear aperture of
the ring light shall be at least 30 % larger than the effective aperture of the LMD
lens.
iii) The ring light source should have a smooth broadband spectrum approximating
CIE standard Illuminant D65, as specified in ISO 11664-2. The spectral
characteristics of the light source shall be kept constant during measurements on
a transparent OLED display. The measurement conditions shall be such that the
transparent OLED display temperature does not increase while measurements are
made.
b) Standard measuring environmental conditions:
1) darkroom conditions;
2) standard setup conditions.
5.1.3.3 Measuring method
For this measurement, the following method shall be applied.
NOTE 1 This method assumes that the scatter properties of the transparent OLED display are independent of the
illumination level on the display.
NOTE 2 It is noted that it is not uncommon for the OLED transmission properties to be largely invariant with the
rendered colour.
NOTE 3 If that can be demonstrated, then the transmission properties can be measured with the display turned
off.
1) Place a white reflectance standard at the sample plane used for the display
measurements. Unless the viewing distance is specified, position the LMD approximately
0,5 m from the sample plane and align the optical axis of the LMD centred and normal to
the reflectance standard surface. Place the ring light facing the reflectance standard,
centred on the optical axis, and positioned at a distance such that its light is incident at a
45° inclination angle to the centre of the measurement field.
2) Allow the ring light source to stabilize. Ensure that the LMD measurement field is centred
within the uniform illumination of the ring light illumination on the reflectance standard.
Measure the luminance L or spectral radiance L (λ) of the light reflected from the
std std
reflectance standard.
3) Calculate the illuminance E (or spectral irradiance E (λ)) of the ring light at the sample
dir dir
plane using the known luminous reflectance factor R (or spectral reflectance factor
std
R (λ)) of the white standard for the same illumination/detector configuration:
std
πL
std
E =
dir (4)
R
std
The calculation of the spectral irradiance has the same form.
4) Replace the reflectance standard with the transparent OLED display positioned at the
same sample plane, with the back surface normal of the display parallel with the LMD
optical axis. The desired measurement location on the display shall be centred about the
measurement field of the LMD.
5) Move the LMD to the front of the transparent OLED di
...