IEC 62679-4-2:2016

Electronic paper displays - Part 4-2: Environmental test methods

IEC 62679-4-2:2016(E) specifies the environmental conditions to determine the environmental reliability of electronic paper display (EPD) panels and/or modules for storage under the assumed usage environment. The scope of this document is restricted to EPDs using either segment, passive, or active matrix with either monochromatic or colour type displays. The measuring methods are intended for EPDs operated in a reflective mode.

General Information

• Status: Published
• Publication Date: 28-Aug-2016
• ICS: 31.120 - Electronic display devices
• ICS: 31.260 - Optoelectronics. Laser equipment
• Technical Committee: TC 110 - Electronic displays
• Drafting Committee: WG 7 - TC 110/WG 7
• Current Stage: PPUB - Publication issued
• Start Date: 29-Aug-2016
• Completion Date: 15-Dec-2016

IEC 62679-4-2:2016 - Electronic paper displays (EPD) - Environmental test methods

Overview

IEC 62679-4-2:2016 defines environmental test methods to determine the environmental reliability of electronic paper displays (EPDs) - panels and modules - during storage under assumed usage conditions. The scope is limited to segment, passive and active matrix EPDs, in monochrome or colour, and is intended for devices operated in reflective mode. The standard sets out measuring conditions, recovery procedures and test methods relevant to storage, temperature, humidity, pressure and light exposure.

Key topics and requirements

• Measuring and reference conditions
  • Standard measuring environmental conditions and atmospheric reference conditions for repeatable measurements.
  • Defined recovery conditions and procedures to assess reversible/irreversible effects after stress.
• Environmental storage tests
  • High temperature and low temperature storage tests to verify long‑term stability in extremes.
  • Temperature shock tests (two‑chamber) and specified temperature change rate tests (one‑chamber) to assess robustness to rapid thermal transitions.
• Temperature/humidity tests
  • Combination temperature/humidity test and temperature/humidity cycling to simulate real-world moisture and thermal cycling.
• Low air pressure
  • Low pressure (altitude) test method for storage when evacuated or transported at reduced pressure.
• Light exposure and solar simulation
  • Procedures for light exposure including direct sunlight, daylight through window glass and inner part exposures.
  • Guidance on solar spectral irradiance, use of xenon‑arc lamps and calibration against CIE solar spectra.
• Reporting
  • Required information to include in specifications and test reports for traceability and comparability.

Practical applications - who uses this standard

• EPD manufacturers - to validate storage robustness, material choices and module assembly.
• Test laboratories and qualification teams - to execute standardized environmental and light exposure tests.
• OEMs and integrators - to specify storage and transport requirements for e‑readers, signage and low‑power reflective displays.
• Procurement, reliability and warranty engineers - to set acceptance criteria and reduce field failures related to environmental stress.

Related standards and references

• IEC 62679-1-1 (Terminology)
• IEC 62679-3-1 (Optical measuring methods)
• IEC 60068-1 and IEC 60068-2-38 (environmental testing general guidance and composite temp/humidity cyclic tests)
• CIE 085-1989 (Solar spectral irradiance) - used for light exposure references

Using IEC 62679-4-2 ensures consistent, repeatable environmental qualification of reflective EPDs, improving product reliability, field performance and supply‑chain confidence.

Standards Content (Sample)

IEC 62679-4-2 ®
Edition 1.0 2016-08
INTERNATIONAL
STANDARD
colour
inside
Electronic paper displays –
Part 4-2: Environmental test methods

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IEC 62679-4-2 ®
Edition 1.0 2016-08
INTERNATIONAL
STANDARD
colour
inside
Electronic paper displays –
Part 4-2: Environmental test methods

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 31.120; 31.260 ISBN 978-2-8322-3607-9

– 2 – IEC 62679-4-2:2016 © IEC 2016
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 atmospheric conditions for reference measurements and tests . 7
4.3 Recovery conditions . 8
4.3.1 General . 8
4.3.2 Controlled recovery conditions . 8
4.3.3 Recovery procedure . 8
5 Measuring methods of environmental properties . 9
5.1 High temperature storage test . 9
5.1.1 Purpose . 9
5.1.2 Storage conditions . 9
5.2 Low temperature storage test . 9
5.2.1 Purpose . 9
5.2.2 Storage conditions . 9
5.3 Temperature shock test – Two chambers . 9
5.3.1 Purpose . 9
5.3.2 Storage conditions . 9
5.4 Specified change rate test of temperature – One chamber . 10
5.4.1 Purpose . 10
5.4.2 Storage conditions . 11
5.5 Combination temperature/humidity test . 12
5.5.1 Purpose . 12
5.5.2 Storage conditions . 12
5.6 Combination temperature/humidity cycle test . 12
5.6.1 Purpose . 12
5.6.2 Storage conditions . 12
5.6.3 Test cycle . 13
5.7 Low air pressure test . 16
5.7.1 Purpose . 16
5.7.2 Storage conditions . 17
5.8 Reporting . 17
6 Measuring methods of light exposure properties . 17
6.1 General remarks . 17
6.1.1 Overview . 17
6.1.2 Irradiance of the sunlight . 17
6.1.3 Spectral irradiance of the sunlight . 18
6.2 Conditioning . 18
6.2.1 General . 18
6.2.2 Temperature . 19
6.2.3 Humidity . 19
6.2.4 Surface contamination . 19
6.2.5 Mounting of device(s) . 19

6.2.6 Test facility . 19
6.2.7 Test apparatus . 19
6.2.8 Laboratory light source . 20
6.3 Procedures . 22
6.3.1 General . 22
6.3.2 Test patterns. 22
6.3.3 Measurements . 23
6.4 Light exposure testing . 23
6.4.1 General . 23
6.4.2 Procedure A – Direct sunlight . 23
6.4.3 Procedure B – Daylight through window glass . 23
6.4.4 Procedure C – Inner parts . 24
6.5 Reporting . 24
6.5.1 Information to be given in the relevant specification . 24
6.5.2 Reporting . 25
Bibliography . 26

Figure 1 – Temperature profile . 10
Figure 2 – Temperature profile . 11
Figure 3 – Combination temperature/humidity cycle followed by exposure to cold . 15
Figure 4 – Combination temperature/humidity cycle not followed by exposure to cold . 16
Figure 5 – Global solar spectral irradiance at sea level . 18
Figure 6 – Examples of test pattern for black and white EPD and for colour EPD . 23

Table 1 – Standard conditions for reference measurements and tests . 7
Table 2 – Spectral irradiance (condensed from CIE 085-1989, Table 4) . 18
a b
Table 3 – Relative spectral irradiance of xenon-arc lamps with daylight filters . 21
ab
Table 4 – Relative spectral irradiance for xenon-arc lamps with window glass filters . 22
Table 5 – Exposure cycles . 24

– 4 – IEC 62679-4-2:2016 © IEC 2016
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRONIC PAPER DISPLAYS –
Part 4-2: Environmental test methods

FOREWORD
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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 62679-4-2 has been prepared by IEC technical committee 110:
Electronic display devices.
The text of this standard is based on the following documents:
CDV Report on voting
110/730/CDV 110/773A/RVC
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 62679 series, published under the general title Electronic paper
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
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– 6 – IEC 62679-4-2:2016 © IEC 2016
ELECTRONIC PAPER DISPLAYS –
Part 4-2: Environmental test methods

1 Scope
This part of IEC 62679 specifies the environmental conditions to determine the environmental
reliability of electronic paper display (EPD) panels and/or modules for storage under the
assumed usage environment. The scope of this document is restricted to EPDs using either
segment, passive, or active matrix with either monochromatic or colour type displays. The
measuring methods are intended for EPDs operated in a reflective mode.
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 62679-1-1, Electronic paper displays – Part 1-1: Terminology
IEC 62679-3-1, Electronic paper displays – Part 3-1: Optical measuring methods
IEC 60068-1, Environmental testing – Part 1: General and guidance
IEC 60068-2-38:2009, Environmental testing – Part 2: Tests – Test Z/AD: Composite
temperature/humidity cyclic test
CIE 085-1989, Solar spectral irradiance
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 62679-1-1,
IEC 60068-1 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
air mass
path length that light from a celestial object takes through the earth’s atmosphere relative to
the length at the zenith where air mass = 1
Note 1 to entry: The air mass is 1/sin (gamma), where gamma is the elevation angle of the sun.
3.2
black standard temperature
temperature of an insulated stainless-steel plate, having a black coating

Note 1 to entry: The black standard temperature represents the maximum surface temperature of specimens
exposed to radiation.
Note 2 to entry: The black coated surface absorbs at least 90 % of the incident radiation flux below λ = 2 500 nm.
Note 3 to entry: The plate is attached to a 5 mm thick baseplate made of a weather resistant polymer for the
insulation.
3.3
black panel temperature
temperature of an un-insulated stainless-steel plate, having a black coating
Note 1 to entry: The back of the metal plate is open to the atmosphere.
3.4
solar constant
E
irradiance by the sunlight on a plane perpendicular to the incident radiation outside the earth's
atmosphere at the mean earth-sun distance
Note 1 to entry: The value of the solar constant is E = 1 367 W/m .
3.5
optical depth
measure of how much light is absorbed when travelling through a medium
Note 1 to entry: A completely transparent medium has an optical depth of zero.
4 Measuring conditions
4.1 Standard measuring environmental conditions
Measurements shall be carried out under the 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.
4.2 Standard atmospheric conditions for reference measurements and tests
If the parameters to be measured depend on temperature, pressure and humidity and their
dependence on temperature, pressure and humidity is unknown, the atmospheres to be
specified shall be selected from the following values, as shown in Table 1. The selected
values shall be noted in the relevant specifications.
Table 1 – Standard conditions for reference measurements and tests
a a, b a
Temperature Relative humidity Air pressure
°C % RH kPa
45 to 75 86 to 106
20, 25, 30, and 35 ± 3
a
Including extreme values.
b 3
Absolute humidity ≤ 22 g/m .
– 8 – IEC 62679-4-2:2016 © IEC 2016
4.3 Recovery conditions
4.3.1 General
After the conditioning period and before making the final measurements, the specimens
should be allowed to stabilize at the ambient temperature, i.e. the temperature at which the
measurements are to be made.
The controlled recovery conditions (see 4.3.2) shall be applied if the electrical parameters to
be measured are affected by the absorbed humidity or surface conditions of the specimens
and change rapidly, for example if the insulation resistance rises considerably within
approximately 2 h after removal of the specimens from a humidity chamber.
If the electrical parameters of the specimens affected by the absorbed humidity or surface
conditions do not vary rapidly, recovery may be carried out in the conditions of 4.2.
If recovery and measurements are performed in separate chambers, the combination of
temperature and humidity conditions shall be such that condensation on the surface of the
specimens does not occur when the specimen is transferred to the measurement chamber.
Most test procedures give the appropriate recovery conditions and duration. These conditions
apply unless otherwise prescribed by the relevant specification.
4.3.2 Controlled recovery conditions
The controlled recovery conditions are as follows:
• Temperature: actual laboratory temperature ± 1 °C provided that it is within the limits fixed
in 4.2, that is, between + 15 °C and + 35 °C.
• Relative humidity: between 45 % and 75 %.
• Air pressure: between 86 kPa and 106 kPa.
• Recovery period: to be stated in the relevant specification if different from that given in the
appropriate method of test.
If, for specific cases, different recovery conditions are necessary, they shall be prescribed by
the relevant specification.
4.3.3 Recovery procedure
The specimen shall be placed in the recovery chamber within 10 min of removal from the
conditioning environment. Where the relevant specification requires measurements to be
made immediately after the recovery period, these measurements shall be completed within
30 min of removal from the recovery chamber. Those characteristics which are expected to
change most rapidly after the specimen is removed from the recovery atmosphere shall be
measured first.
In order to prevent moisture being absorbed or lost by the specimen when removed from the
recovery chamber, the temperature of the recovery chamber shall not deviate from the
laboratory ambient temperature by more than 1 °C. This necessitates the use of a chamber
having good thermal conductivity in which the relative humidity can be closely controlled.

5 Measuring methods of environmental properties
5.1 High temperature storage test
5.1.1 Purpose
The purpose of this non-operational test is to measure the ability of EPD panels and modules
to withstand high temperature in storage.
5.1.2 Storage conditions
Standard measuring is implemented under the standard environmental conditions.
Temperature and duration time are as follows:
a) Temperature
The temperature shall be selected from the values given below depending on application.
The temperature used shall be noted in the report.
(100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30 ± 3) °C
b) Duration time
The duration shall be selected from the values given below depending on application. The
duration used shall be noted in the report.
2 h, 16 h, 24 h, 48 h, 72 h, 96 h, 120 h, 168 h, 192 h, 240 h, 300 h, 500 h and 1 000 h
5.2 Low temperature storage test
5.2.1 Purpose
The purpose of this non-operational test is to measure the ability of EPD panels and modules
to withstand low temperature in storage.
5.2.2 Storage conditions
Standard measuring is implemented under the standard environmental conditions.
Temperature and duration time are as follows:
a) Temperature
The temperature shall be selected from the values given below depending on application.
The temperature used shall be noted in the report.
(–50, –45, –40, –35, –30, –25, –20, –15, –10, –5, 0 ± 3) °C
b) Duration time
The duration shall be selected from the values given below depending on application. The
duration used shall be noted in the report.
2 h, 16 h, 24 h, 48 h, 72 h, 96 h, 120 h, 168 h, 192 h, 240 h, 300 h, 500 h and 1 000 h
5.3 Temperature shock test – Two chambers
5.3.1 Purpose
The purpose of this non-operational test is to measure the ability of EPD panels and modules
to withstand rapid changes of ambient temperature.
5.3.2 Storage conditions
Standard measuring is implemented under the standard environmental conditions.

– 10 – IEC 62679-4-2:2016 © IEC 2016
The schematic diagram of temperature profile is shown in Figure 1.
Temperature, duration time, transition time and number of cycles are as follows:
a) High temperature
The temperature shall be selected from the values given below depending on application.
(100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30 ± 3) °C
The temperature used shall be noted in the report.
b) Low temperature
The temperature shall be selected from the values given below depending on application.
(–50, –45, –40, –35, –30, –25, –20, –15, –10, –5, 0 ± 3) °C
The temperature used shall be noted in the report.
c) Duration time
3 h, 2 h, 1 h, 30 min, 10 min
d) Transition time
2 min to 3 min, 20 s to 30 s, less than 10 s
e) Number of cycles
5 or 10
T
H
t
Time
t
t t
2 2
T
L
First cycle
IEC
T High temperature
H
T Low temperature
L
t Duration time
t Transition time
Figure 1 – Temperature profile
5.4 Specified change rate test of temperature – One chamber
5.4.1 Purpose
The purpose of this non-operational test is to measure the ability of EPD panels and modules
to withstand specified change rate of ambient temperature.
Temperature
5.4.2 Storage conditions
Standard measuring is implemented under the standard environmental conditions.
The schematic diagram of temperature profile is shown in Figure 2.
Temperature and duration time are as follows:
a) High temperature
The temperature shall be selected from the values given below depending on application.
(100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30 ± 3) °C
The temperature used shall be noted in the report.
b) Low temperature
The temperature shall be selected from the values given below depending on application.
(–50, –45, –40, –35, –30, –25, –20, –15, –10, –5, 0 ± 3) °C
The temperature used shall be noted in the report.
c) Temperature change rate
1 °C/min ± 0,2 °C/min, 3 °C/min ± 0,6 °C/min, 5 °C/min ± 1 °C/min, 10 °C/min ± 2 °C/min,
15 °C/min ± 3 °C/min
d) Duration time
3 h, 2 h, 1h, 30 min, 10 min
e) Number of cycles
5 or 10
t
T
H
Time
T
L
t
First cycle
IEC
T High temperature
H
T Low temperature
L
t Duration time
Figure 2 – Temperature profile
Temperature
– 12 – IEC 62679-4-2:2016 © IEC 2016
5.5 Combination temperature/humidity test
5.5.1 Purpose
The purpose of this non-operational test is to measure the ability of EPD panels and modules
to withstand a combination of temperature and relative humidity (RH).
5.5.2 Storage conditions
Standard measuring is implemented under the standard environmental conditions.
Temperature and duration time are as follows:
a) Temperature
The temperature shall be selected from the values given below depending on application.
(100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30 ± 3) °C
The temperature used shall be noted in the report.
b) Humidity
(80, 85, 90, 93 ± 3) %RH
c) Duration time
The duration time at test temperature and humidity shall be selected from the values given
below d
...