Ergonomics of human-system interaction — Electronic paper display — Indoor use

ISO/TS 21144:2016 establishes test methods for evaluating electronic paper display (EPD) when used in indoor tasks and environments. It is intended to be applied together with the measurement procedures of ISO 9241-305 and the generic requirements of ISO 9241-303 to define compliance routes suitable for EPD.

Ergonomie de l'interaction homme-système — Affichage de papier électronique — Utilisation à l'intérieure

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Status
Withdrawn
Publication Date
11-Aug-2016
Withdrawal Date
11-Aug-2016
Current Stage
9599 - Withdrawal of International Standard
Completion Date
24-Jun-2020
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TECHNICAL ISO/TS
SPECIFICATION 21144
First edition
2016-08-15
Ergonomics of human-system
interaction — Electronic paper display
— Indoor use
Ergonomie de l’interaction homme-système — Affichage de papier
électronique — Utilisation à l’intérieure
Reference number
ISO/TS 21144:2016(E)
©
ISO 2016

---------------------- Page: 1 ----------------------
ISO/TS 21144:2016(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2016 – All rights reserved

---------------------- Page: 2 ----------------------
ISO/TS 21144:2016(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Electronic paper display for indoor use — Display laboratory method .1
4.1 Intended context of use . 1
4.2 Information about the technology . 4
4.3 Compliance assessment . 5
Bibliography .17
© ISO 2016 – All rights reserved iii

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ISO/TS 21144:2016(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment,
as well as information about ISO’s adherence to the World Trade Organization (WTO) principles in the
Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html
The committee responsible for this document is ISO/TC 159, Ergonomics, Subcommittee SC4, Ergonomics
of human–system interaction.
iv © ISO 2016 – All rights reserved

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ISO/TS 21144:2016(E)

Introduction
The publication of the ISO 9241-300 series of International Standards addressed a wide range of visual
display tasks and environments and provided the means for evaluating them. Not covered by those
standards was the more recently developed electronic paper display (EPD) technology.
Owing to its unique optical characteristics, the current existing measuring methods may not be suitable
for evaluating EPD.
Until measuring methods and compliance routes for EPD can be developed in the ISO 9241-300 series,
this Technical Specification provides intermediate instruction and guidance. Using this Technical
Specification together with ISO 9241-303 and ISO 9241-305 gives a good understanding of how to
analyse an environment for which a specific analysis and compliance method does not yet exist.
© ISO 2016 – All rights reserved v

---------------------- Page: 5 ----------------------
TECHNICAL SPECIFICATION ISO/TS 21144:2016(E)
Ergonomics of human-system interaction — Electronic
paper display — Indoor use
1 Scope
This Technical Specification establishes test methods for evaluating electronic paper display (EPD)
when used in indoor tasks and environments. It is intended to be applied together with the measurement
procedures of ISO 9241-305 and the generic requirements of ISO 9241-303 to define compliance routes
suitable for EPD.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 9241-302, Ergonomics of human-system interaction — Part 302: Terminology for electronic visual
displays
ISO 9241-303, Ergonomics of human-system interaction — Part 303: Requirements for electronic visual
displays
ISO 9241-305, Ergonomics of human-system interaction — Part 305: Optical laboratory test methods for
electronic visual displays
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 9241-302 and the
following apply.
3.1
electronic paper display
EPD
electronic display that shows information by diffuse reflection and holds the image with low power
consumption
3.2
electronic reader
e-reader
electronic device which shows information using EPD
4 Electronic paper display for indoor use — Display laboratory method
4.1 Intended context of use
The attributes of the user, environment, tasks and the use of electronic readers based on electronic
paper display (EPD) are summarized in Table 1. Attributes are derived from analysis of the intended
context of use and are an essential prerequisite for the compliance assessment. Therefore, context
elements different from those described in this method could influence the Pass/Fail criteria.
© ISO 2016 – All rights reserved 1

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ISO/TS 21144:2016(E)

The supplier shall specify the intended context of use as well as the value or value range of an attribute.
The values specified shall match the intended context of use. The intended context of use is part of the
compliance report.
NOTE 1 Electronic readers with a diagonal of the active display area of up to approximately 7,1 inches
(180 mm), corresponding to ISO A6 paper size, and up to 20,2 inches (514 mm), corresponding to ISO A3 paper
size, are considered in this compliance route for typical visual display tasks for indoor use in work environments.
NOTE 2 Automotive environments, such as those of cars, trains and other vehicles, are not addressed here.
Table 1 — Intended context of use
Element Attribute Quantification
User Age and vision User with normal or to normal corrected vision of any age,
7 years or older (any literate user).
Environment Design screen illuminance, E At indoor locations:
S
—  minimum 20 lx
—  maximum 1 500 lx
The supplier shall specify the design screen illuminance
(or its range).
Typical components of the illu- N/A.
mination: large aperture source
There is no evaluation of unwanted reflections.
(15°) and small aperture source
(1°) illumination.
Illuminant For this compliance route CIE illuminant A, D50, D65, F11
[5]
and F12 are considered. The supplier may specify the
intended illuminant.
All these illuminants exist at every illuminance level of
indoors use. Often in combinations. It is assumed that by
verifying that the visual display complies in each of the
illuminants, the visual display will also comply with any
combination of illuminants.
The compliance assessment need only be performed once,
with a spectrally broad-band laboratory illumination. The
compliance calculations are then made using spectral cal-
culations and repeated for each of the specified illumina-
tion levels and illuminants.
Ambient temperature For this compliance route an ambient temperature of
approximate 15°C to 35°C is considered, if not otherwise
specified by the supplier.
2 © ISO 2016 – All rights reserved

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ISO/TS 21144:2016(E)

Table 1 (continued)
Element Attribute Quantification
Task Content and perception For this compliance route the following contexts for
perception of information are considered, if not otherwise
specified by the supplier.
Artificial information
Visualization of objects and scenes that do not have origi-
nals in our world, e.g. text (i.e. alphanumeric characters),
graphical signs, symbols, etc. in monochrome (including
achromatic) and/or multicolour (including full-colour)
presentation.
The Pass/Fail criteria may contain three different require-
ment levels, “High”, “Medium” and “Low”, which determine
the degree to which a criterion is fulfilled:
“High” for visual display tasks require high performance
in e.g. colour gamut, grey scale but also higher comfort
regarding character attributes;
“Medium” for general visual display tasks require suf-
ficient performance to perceive colour and to read the
information without discomfort by the user;
“Low” for visual display tasks require low performance
in e.g. colour gamut and grey scale, but with sufficient
performance to read the information without discomfort
by the user.
Amount of information Preferred screen size for sufficient amount of information
with appropriate object size and resolution.
Image type For this compliance route the visual display shall be capa-
ble of displaying still and quasi-static images.
Design viewing distance, The minimum design viewing distance, D ,
design,view,min
D is > 200 mm.
design,view
The supplier shall specify D .
design,view
Design viewing direction, Within a specific range of angles from the normal. For
Θ , Φ this compliance route, perpendicular viewing direction
D D
is assumed, if not otherwise specified by the supplier.
Therefore, the default design viewing direction, (Θ , Φ ),
D D
is (0°, −).
© ISO 2016 – All rights reserved 3

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ISO/TS 21144:2016(E)

Table 1 (continued)
Element Attribute Quantification
Task Design viewing direction range For this compliance route, a design viewing direction
(angle of inclination and azimuth) range of up to 80° is considered, if not otherwise specified
by the supplier (as shown below).
Therefore, the maximum angle of inclination, Θ, is 40°. The
azimuth angle, Φ, is 0° to 360°
Eye and head position From fixed to moving.
Number of users Typically single.
Usage Display handling For this compliance route, stationary and portable display
handling is considered, unless otherwise specified by the
supplier.
4.2 Information about the technology
The basic physical attributes of electronic readers are given in Table 2.
The supplier shall submit a detailed technical specification which includes
— rated voltage,
— rated frequency,
— rated current,
— rated power consumption,
— panel specification,
— horizontal/vertical pixel size,
— original resolution,
— sub-pixel drawing,
— anti-reflection treatment,
— pixel fault declaration,
— prepared gamma-value, and
— factory setting of brightness, contrast, colour control.
The supplier shall also submit the test pattern, if required.
4 © ISO 2016 – All rights reserved

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ISO/TS 21144:2016(E)

Table 2 — Basic physical attributes of the visual display
Basic physical attribute Description
Optical mode of operation Reflective
Mode of observation Direct-view
Diagonal of the active display area Approximately 7,1 inches (180 mm), corresponding to ISO-A6, and up to
20,2 inches (514 mm), corresponding to ISO-A3 paper sizes.
Aspect ratio Depending on application
Resolution (addressable pixels) Depending on application
Internal light source None or built-in light source.
If an electronic reader has supplement illumination, such as an integrated
lighting unit on an EPD, either remove it or turn it off during testing.
Touch screen None or built-in
4.3 Compliance assessment
The compliance assessment shall be given according to Tables 3 to 13.
Electronic paper displays for electronic readers are used in a wide variety of illumination conditions.
The darkroom or laboratory illumination condition can vary greatly from actual usage conditions. The
approach of this compliance route is to perform the measurements under stable laboratory conditions
with darkroom and laboratory light source illumination and then convert by calculation to the contexts
of use prescribed by the compliance route.
Unless otherwise explicitly defined, a requirement is met only if it is met for all illuminance levels and
illuminants defined in the intended context of use.
Table 3 — Viewing conditions
Attribute Pass/Fail criteria based on requirements and Measuring Assessment and
intended context of use method reporting
Design viewing The design viewing distance is Supplier Use supplier-spec-
distance specification, ified values or
a)   for children, a minimum of 200 mm;
intended con- values obtained from
text of use intended context
b)   for adults, a minimum of 300 mm;
of use. Report the
c)   for elderly people, a minimum of 450 mm.
resulting value.
These requirements need to be considered in con-
junction with the character height requirements.
Design viewing The visual display shall conform to all optical Supplier Use supplier-spec-
direction requirements over a relevant range of viewing specification, ified values or
directions. The design viewing direction (Θ , Φ ), as intended con- values obtained from
D D
well as the design viewing direction range shall be text of use intended context
specified. of use. Report the
resulting value.
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ISO/TS 21144:2016(E)

Table 4 — Reflectance factor and illuminance
Attribute Pass/Fail criteria based on requirements and intended Measuring Assessment and report-
context of use method ing
Illuminance The supplier shall specify the minimum and maximum design Supplier specifi- Use supplier-specified
screen illuminance, E , as well as the illuminant. cation, intended values or values obtained
S
context of use from the intended con-
The following applies.
text of use.
a)  Requirement level “Low”
Report the resulting
values.
All requirements shall be met in at least one specified but not all
lighting conditions.
b)  Requirement level “Medium”
All requirements shall be met in all lighting conditions.
c)  Requirement level “High”
All requirements shall be met in all lighting conditions.
Reflectance factor The visual display shall fulfil the following requirements. ISO 9241-305:2008, Determine the reflection
P 16.1A coefficient according to
a)  Requirement level “Low”
the measuring method
The display shall
ISO 9241-305:2008,
The visual display shall have a minimum reflectance factor
be in its highest
P16.5.
of R = 20 % in order to get a minimum display luminance of
reflective state.
L = R × E /π.
S
Compare the minimum
display reflectance factor
b)  Requirement level “Medium”
for passed or failed as
The visual display shall have a minimum reflectance factor
well as the fulfilled re-
of R = 38 % in order to get a minimum display luminance of
quirement level.
L = R × E /π.
S
c)  Requirement level “High”
The visual display shall have a minimum reflectance factor of
R = 55 % in order to obtain a minimum display luminance of
L = R × E /π, where
S
   L  is the display luminance;
   R  is the reflectance factor (reflectometer value) of the reflec-
tive visual display;
   E is the design screen illuminance.
S
These luminance requirements need to be considered in con-
junction with the contrast requirements.
6 © ISO 2016 – All rights reserved

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ISO/TS 21144:2016(E)

Table 5 — Special physical environments
Attribute Pass/Fail criteria based on requirements and Measuring Assessment and
intended context of use method reporting
Excessive tem- When operation of visual display devices is required Supplier Use a supplier-spec-
peratures in environments where temperatures are approach- specification, ified value or a value
ing 0°C or +40°C, users should take precautions with intended con- obtained from the
equipment and personal precautions to ensure satis- text of use intended context of
factory and safe completion of their tasks. use.
The following applies. Check whether
the supplier has
a)  Requirement level “Low”
specified the use for
All requirements shall be met within the range extreme tempera-
15°C to 30°C. tures and report the
resulting value.
b)  Requirement level “Medium”
All requirements shall be met within the range
0°C to 40°C.
c)  Requirement level “High”
All requirements shall be met within the range
−20°C to 40°C.
Table 6 — Visual artefacts
Attribute Pass/Fail criteria based on requirements and intended Measuring Assessment and report-
context of use method ing
Contrast uniformity a)  Lateral uniformity criteria ISO 9241-305:2008, Evaluate the contrast
P 18.5 for a) uniformity and report the
For an intended uniform appearance, the contrast uniformity,
P 18.8 for b) resulting value for passed
or failed.
   CR = CR /CR ,
uniformity min max
shall exceed 50 %
where CR is the luminance contrast.
b)  Directional uniformity criteria
The visual display shall have a sufficient contrast uniformity
over all relevant viewing directions (see design viewing direc-
tion).
1.  CR shall exceed the limit CR .
min
2.  There shall be no contrast inversion in the intended viewing
direction range.
See Table 9 for CR
min.
Screen and face- The visual display should be in the fault class Class 0, with a ISO 9241-305:2008, Report the supplier’s
Pixel
plate defects recommended maximum of Class I. M 21.7 declaration.
Pixel
If not in Class 0, the supplier shall specify the Class of the It is recom- Evaluate pixel and
Pixel Pixel
visual display in accordance with Table 11. mended that subpixel faults by direct
hemispherical observation.
illumination be
Determine and report the
used.
fault class.
Rounding policy:
round down:
  x,00 to x,49 → x
round up:
   x,50 to x,99 → x + 1
© ISO 2016 – All rights reserved 7

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ISO/TS 21144:2016(E)

Table 7 — Pixel fault classification
Type 3
Cluster with more
Cluster of
(see table footnotes)
Class Type 1 Type 2 than one type 1 or
Pixel
type 3 faults
type 2 faults
Stuck high Stuck low
0 0 0 0 0 0 0
I 1 1 2 1 0 0
(for Type 1 1 1 3 0 0
3 = 5 PSU)
1 1 0 5 0 0
II 2 2 5 0 0 1
(for Type 2 2 5 – 1 × n 2 × n 0 1
II II
3 = 10 PSU)
2 2 0 10 0 1
III 5 15 50 0 0 5
(for Type 5 15 50 – 1 × n 2 × n 0 5
III III
3 = 100 PSU)
5 15 0 100 0 5
8 © ISO 2016
...

TECHNICAL ISO/TS
SPECIFICATION 21144
First edition
Ergonomics of human-system
interaction — Electronic paper display
— Indoor use
Ergonomie de l’interaction homme-système — Affichage de papier
électronique — Utilisation à l’intérieure
PROOF/ÉPREUVE
Reference number
ISO/TS 21144:2016(E)
©
ISO 2016

---------------------- Page: 1 ----------------------
ISO/TS 21144:2016(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2016 – All rights reserved

---------------------- Page: 2 ----------------------
ISO/TS 21144:2016(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Electronic paper display for indoor use — Display laboratory method .1
4.1 Intended context of use . 1
4.2 Information about the technology . 4
4.3 Compliance assessment . 5
Bibliography .17
© ISO 2016 – All rights reserved PROOF/ÉPREUVE iii

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ISO/TS 21144:2016(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 159, Ergonomics, Subcommittee SC4, Ergonomics
of human–system interaction.
iv PROOF/ÉPREUVE © ISO 2016 – All rights reserved

---------------------- Page: 4 ----------------------
ISO/TS 21144:2016(E)

Introduction
The publication of the ISO 9241-300 series of International Standards addressed a wide range of visual
display tasks and environments and provided the means for evaluating them. Not covered by those
standards was the more recently developed electronic paper display (EPD) technology.
Owing to its unique optical characteristics, the current existing measuring methods may not be suitable
for evaluating EPD.
Until measuring methods and compliance routes for EPD can be developed in the ISO 9241-300 series,
this Technical Specification provides intermediate instruction and guidance. Using this Technical
Specification together with ISO 9241-303 and ISO 9241-305 gives a good understanding of how to
analyse an environment for which a specific analysis and compliance method does not yet exist.
© ISO 2016 – All rights reserved PROOF/ÉPREUVE v

---------------------- Page: 5 ----------------------
TECHNICAL SPECIFICATION ISO/TS 21144:2016(E)
Ergonomics of human-system interaction — Electronic
paper display — Indoor use
1 Scope
This Technical Specification establishes test methods for evaluating electronic paper display (EPD)
when used in indoor tasks and environments. It is intended to be applied together with the measurement
procedures of ISO 9241-305 and the generic requirements of ISO 9241-303 to define compliance routes
suitable for EPD.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 9241-302, Ergonomics of human-system interaction — Part 302: Terminology for electronic visual
displays
ISO 9241-303, Ergonomics of human-system interaction — Part 303: Requirements for electronic visual
displays
ISO 9241-305, Ergonomics of human-system interaction — Part 305: Optical laboratory test methods for
electronic visual displays
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 9241-302 and the
following apply.
3.1
electronic paper display
EPD
electronic display that shows information by diffuse reflection and holds the image with low power
consumption
3.2
electronic reader
e-reader
electronic device which shows information using EPD
4 Electronic paper display for indoor use — Display laboratory method
4.1 Intended context of use
The attributes of the user, environment, tasks and the use of electronic readers based on electronic
paper display (EPD) are summarized in Table 1. Attributes are derived from analysis of the intended
context of use and are an essential prerequisite for the compliance assessment. Therefore, context
elements different from those described in this method could influence the Pass/Fail criteria.
© ISO 2016 – All rights reserved PROOF/ÉPREUVE 1

---------------------- Page: 6 ----------------------
ISO/TS 21144:2016(E)

The supplier shall specify the intended context of use as well as the value or value range of an attribute.
The values specified shall match the intended context of use. The intended context of use is part of the
compliance report.
NOTE 1 Electronic readers with a diagonal of the active display area of up to approximately 7,1 inches
(180 mm), corresponding to ISO A6 paper size, and up to 20,2 inches (514 mm), corresponding to ISO A3 paper
size, are considered in this compliance route for typical visual display tasks for indoor use in work environments.
NOTE 2 Automotive environments, such as those of cars, trains and other vehicles, are not addressed here.
Table 1 — Intended context of use
Element Attribute Quantification
User Age and vision User with normal or to normal corrected vision of any age,
7 years or older (any literate user).
Environment Design screen illuminance, E At indoor locations:
S
—  minimum 20 lx
—  maximum 1 500 lx
The supplier shall specify the design screen illuminance
(or its range).
Environment Typical components of the illu- N/A.
mination: large aperture source
There is no evaluation of unwanted reflections.
(15°) and small aperture source
(1°) illumination.
Illuminant For this compliance route CIE illuminant A, D50, D65, F11
[5]
and F12 are considered. The supplier may specify the
intended illuminant.
All these illuminants exist at every illuminance level of
indoors use. Often in combinations. It is assumed that by
verifying that the visual display complies in each of the
illuminants, the visual display will also comply with any
combination of illuminants.
The compliance assessment need only be performed once,
with a spectrally broad-band laboratory illumination. The
compliance calculations are then made using spectral cal-
culations and repeated for each of the specified illumina-
tion levels and illuminants.
Ambient temperature For this compliance route an ambient temperature of
approximate 15°C to 35°C is considered, if not otherwise
specified by the supplier.
2 PROOF/ÉPREUVE © ISO 2016 – All rights reserved

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ISO/TS 21144:2016(E)

Table 1 (continued)
Element Attribute Quantification
Task Content and perception For this compliance route the following contexts for
perception of information is considered, if not otherwise
specified by the supplier.
Artificial information
Visualization of objects and scenes that do not have origi-
nals in our world, e.g. text (i.e. alphanumeric characters),
graphical signs, symbols, etc. in monochrome (including
achromatic) and/or multicolour (including full-colour)
presentation.
The Pass/Fail criteria may contain three different require-
ment levels, “High”, “Medium” and “Low”, which determine
the degree to which a criterion is fulfilled:
“High” for visual display tasks require high performance
in e.g. colour gamut, grey scale but also higher comfort
regarding character attributes;
“Medium” for general visual display tasks require suf-
ficient performance to perceive colour and to read the
information without discomfort by the user;
“Low” for visual display tasks require low performance
in e.g. colour gamut and grey scale, but with sufficient
performance to read the information without discomfort
by the user.
Amount of information Preferred screen size for sufficient amount of information
with appropriate object size and resolution.
Image type For this compliance route the visual display shall be capa-
ble of displaying still and quasi-static images.
Design viewing distance, The minimum design viewing distance, D ,
design,view,min
D is > 200 mm.
design,view
The supplier shall specify D .
design,view
Design viewing direction, Within a specific range of angles from the normal. For
Θ , Φ this compliance route, perpendicular viewing direction
D D
is assumed, if not otherwise specified by the supplier.
Therefore, the default design viewing direction, (Θ , Φ ),
D D
is (0°, −).
© ISO 2016 – All rights reserved PROOF/ÉPREUVE 3

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ISO/TS 21144:2016(E)

Table 1 (continued)
Element Attribute Quantification
Design viewing direction range For this compliance route, a design viewing direction
(angle of inclination and azimuth) range of up to 80° is considered, if not otherwise specified
by the supplier (as shown below).
Therefore, the maximum angle of inclination, Θ, is 40°. The
azimuth angle, Φ, is 0° to 360°
Task Eye and head position From fixed to moving.
Number of users Typically single.
Usage Display handling For this compliance route, stationary and portable display
handling is considered, unless otherwise specified by the
supplier.
4.2 Information about the technology
The basic physical attributes of electronic readers are given in Table 2.
The supplier shall submit a detailed technical specification which includes
— rated voltage,
— rated frequency,
— rated current,
— rated power consumption,
— panel specification,
— horizontal/vertical pixel size,
— original resolution,
— sub-pixel drawing,
— anti-reflection treatment,
— pixel fault declaration,
— prepared gamma-value, and
— factory setting of brightness, contrast, colour control.
The supplier shall also submit the test pattern, if required.
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Table 2 — Basic physical attributes of the visual display
Basic physical attribute Description
Optical mode of operation Reflective
Mode of observation Direct-view
Diagonal of the active display area Approximately 7,1 inches (180 mm), corresponding to ISO-A6, and up
to 20,2 inches (514 mm), corresponding to ISO-A3 paper sizes.
Aspect ratio Depending on application
Resolution (addressable pixels) Depending on application
Internal light source None or built-in light source.
If an electronic reader has supplement illumination, such as an integrated
lighting unit on an EPD, either remove it or turn it off during testing.
Touch screen None or built-in
4.3 Compliance assessment
The compliance assessment shall be given according to Tables 3 to 13.
Electronic paper displays for electronic readers are used in a wide variety of illumination conditions.
The darkroom or laboratory illumination condition can vary greatly from actual usage conditions. The
approach of this compliance route is to perform the measurements under stable laboratory conditions
with darkroom and laboratory light source illumination and then convert by calculation to the contexts
of use prescribed by the compliance route.
Unless otherwise explicitly defined, a requirement is met only if it is met for all illuminance levels and
illuminants defined in the intended context of use.
Table 3 — Viewing conditions
Attribute Pass/Fail criteria based on requirements and Measuring Assessment and
intended context of use method reporting
Design viewing The design viewing distance is Supplier Use supplier-spec-
distance specification, ified values or
a)   for children, a minimum of 200 mm;
intended con- values obtained from
b)   for adults, a minimum of 300 mm; text of use intended context
of use. Report the
c)   for elderly people, a minimum of 450 mm.
resulting value.
These requirements need to be considered in con-
junction with the character height requirements.
Design viewing The visual display shall conform to all optical Supplier Use supplier-spec-
direction requirements over a relevant range of viewing specification, ified values or
directions. The design viewing direction (Θ , Φ ), as intended con- values obtained from
D D
well as the design viewing direction range shall be text of use intended context
specified. of use. Report the
resulting value.
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Table 4 — Reflectance factor and illuminance
Attribute Pass/Fail criteria based on requirements and intended Measuring Assessment and report-
context of use method ing
Illuminance The supplier shall specify the minimum and maximum design Supplier specifi- Use supplier-specified
screen illuminance, E , as well as the illuminant. cation, intended values or values obtained
S
context of use from the intended con-
The following applies.
text of use.
a)  Requirement level “Low”
Report the resulting
values.
All requirements shall be met in at least one specified but not all
lighting conditions.
b)  Requirement level “Medium”
All requirements shall be met in all lighting conditions.
c)  Requirement level “High”
All requirements shall be met in all lighting conditions.
Reflectance factor The visual display shall fulfil the following requirements. ISO 9241-305:2008, Determine the reflection
P 16.1A coefficient according to
a)  Requirement level “Low”
the measuring method
The display shall
ISO 9241-305:2008,
The visual display shall have a minimum reflectance factor
be in its highest
P16.5.
of R = 20 % in order to get a minimum display luminance of
reflective state.
L = R × E /π.
S
Compare the minimum
display reflectance factor
b)  Requirement level “Medium”
for passed or failed as
The visual display shall have a minimum reflectance factor
well as the fulfilled re-
of R = 38 % in order to get a minimum display luminance of
quirement level.
L = R × E /π.
S
c)  Requirement level “High”
The visual display shall have a minimum reflectance factor of
R = 55 % in order to obtain a minimum display luminance of
L = R × E /π, where
S
   L  is the display luminance;
   R  is the reflectance factor (reflectometer value) of the reflec-
tive visual display;
   E is the design screen illuminance.
S
These luminance requirements need to be considered in con-
junction with the contrast requirements.
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Table 5 — Special physical environments
Attribute Pass/Fail criteria based on requirements and Measuring Assessment and
intended context of use method reporting
Excessive tem- When operation of visual display devices is required Supplier Use a supplier-spec-
peratures in environments where temperatures are approach- specification, ified value or a value
ing 0°C or +40°C, users should take precautions with intended con- obtained from the
equipment and personal precautions to ensure satis- text of use intended context of
factory and safe completion of their tasks. use.
The following applies. Check whether
the supplier has
a)  Requirement level “Low”
specified the use for
All requirements shall be met within the range extreme tempera-
15°C to 30°C. tures and report the
resulting value.
b)  Requirement level “Medium”
All requirements shall be met within the range
0°C to 40°C.
c)  Requirement level “High”
All requirements shall be met within the range
−20°C to 40°C.
Table 6 — Visual artefacts
Attribute Pass/Fail criteria based on requirements and intended Measuring Assessment and report-
context of use method ing
Contrast uniformity a)  Lateral uniformity criteria ISO 9241-305:2008, Evaluate the contrast
P 18.5 for a) uniformity and report the
For an intended uniform appearance, the contrast uniformity,
P 18.8 for b) resulting value for passed
or failed.
   CR = CR /CR ,
uniformity min max
shall exceed 50 %
where CR is the luminance contrast.
b)  Directional uniformity criteria
The visual display shall have a sufficient contrast uniformity
over all relevant viewing directions (see design viewing direc-
tion).
1.  CR shall exceed the limit CR .
min
2.  There shall be no contrast inversion in the intended viewing
direction range.
See Table 9 for CR
min.
Screen and face- The visual display should be in the fault class Class 0, with a ISO 9241-305:2008, Report the supplier’s
Pixel
plate defects recommended maximum of Class I. M 21.7 declaration.
Pixel
If not in Class 0, the supplier shall specify the Class of the It is recom- Evaluate pixel and
Pixel Pixel
visual display in accordance with Table 11. mended that subpixel faults by direct
hemispherical observation.
illumination be
Determine and report the
used.
fault class.
Rounding policy:
round down:
  x,00 to x,49 → x
round up:
   x,50 to x,99 → x + 1
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Table 7 — Pixel fault classification
Type 3
Cluster with more
Cluster of
(see table footnotes)
Class Type 1 Type 2 than one type 1 or
Pixel
type 3 faults
type 2 faults
Stuck high Stuck low
0 0 0 0 0 0 0
I 1 1 2 1 0 0
(for Type 1 1 1 3 0 0
3 = 5 PSU)
1 1 0 5 0 0
II 2 2 5 0 0 1
(for Type 2 2 5 – 1 × n 2 × n 0 1
II II
3 = 10 PSU)
2 2 0 10 0 1
III 5 15 50 0 0 5
(for Type 5 15 50 – 1 × n 2 × n 0 5
III III
3 = 100 PSU)
5 15 0 100 0 5
IV 50 150 500 0
...

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