IEC 61988-4-2:2012

IEC 61988-4-2 ®
Edition 1.0 2012-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Plasma display panels –
Part 4-2: Environmental testing methods – Panel strength

Panneaux d’affichage à plasma –
Partie 4-2: Méthodes d'essais d'environnement – Résistance des panneaux
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IEC 61988-4-2 ®
Edition 1.0 2012-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Plasma display panels –
Part 4-2: Environmental testing methods – Panel strength

Panneaux d’affichage à plasma –

Partie 4-2: Méthodes d'essais d'environnement – Résistance des panneaux

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX N
ICS 31.120; 31.260 ISBN 978-2-88912-049-9

– 2 – 61988-4-2 © IEC:2012
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Structure of measuring equipment . 6
5 Standard measuring conditions . 6
6 Measuring methods . 6
6.1 Ball drop strength . 6
6.1.1 Purpose . 6
6.1.2 Measuring equipment . 6
6.1.3 Applicability . 6
6.1.4 Measurement layout . 6
6.1.5 Measuring point . 8
6.1.6 Ball and drop height . 8
6.1.7 Measuring procedure . 9
6.2 Partial heating strength . 9
6.2.1 Purpose . 9
6.2.2 Measuring equipment . 9
6.2.3 Measuring environmental conditions . 10
6.2.4 Measuring layout . 10
6.2.5 System diagram . 12
6.2.6 Measuring positions . 12
6.2.7 Heating rate and maximum temperature . 13
6.2.8 Measuring procedure . 13
Bibliography . 14

Figure 1 – Setting of PDP module (side view) . 7
Figure 2 – Setting of PDP module using spacers (side view) . 7
Figure 3 – Setting of PDP panel (side view) . 7
Figure 4 – Measuring layout of ball drop strength (side view) . 8
Figure 5 – Measuring points . 8
Figure 6 – PDP panel setting . 11
Figure 7 – Setting of thermal sensor (sectional view) . 11
Figure 8 – Set up of measuring equipment . 12
Figure 9 – Measuring positions . 12

Table 1 – Ball and drop height . 9

61988-4-2 © IEC:2012 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PLASMA DISPLAY PANELS –
Part 4-2: Environmental testing methods –
Panel strength
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61988-4-2 has been prepared by IEC technical committee 110:
Electronic display devices.
The text of this standard is based on the following documents:
FDIS Report on voting
110/354/FDIS 110/369/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all the parts in the IEC 61988 series, published under the general title Plasma display
panels, can be found on the IEC website.

– 4 – 61988-4-2 © IEC:2012
Future Part 4-x standards in this series will include the new title component: Environmental
testing methods, as cited above. Titles of existing Part 4-x standards in this series will be
updated accordingly at the time of the next edition.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
61988-4-2 © IEC:2012 – 5 –
PLASMA DISPLAY PANELS –
Part 4-2: Environmental testing methods –
Panel strength
1 Scope
This part of IEC 61988 defines testing methods for evaluating mechanical characteristics of
plasma display modules (PDP modules) in the following areas:
a) Ball drop breaking strength of panels;
b) Partial heating strength of panels.
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.
IEC 60068-1:1988, Environmental Testing – Part 1: General and guidance
IEC 61988-1, Plasma display panels – Part 1: Terminology and letter symbols
IEC 61988-2-1, Plasma display panels – Part 2-1: Measuring methods – Optical and
optoelectrical
IEC 61988-4, Plasma display panels – Part 4: Climatic and mechanical testing methods
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60068-1 and
IEC 61988-1 and the following apply.
3.1
ball drop breaking strength
breaking strength against a ball drop impact measured as a breaking drop height using a ball
whose weight and material are previously determined
3.2
rubber heater
soft and flexible sheet (generally made from thermally conductive rubber) in which electric
heating element is molded
Note 1 to entry: Temperature uniformity of rubber heater is obtained by the layout of heating wire in the sheet and
its material.
3.3
partial heating strength
mechanical strength under a thermal stress caused by heating a limited area of panel

– 6 – 61988-4-2 © IEC:2012
Note 1 to entry: Still images including bright small part(s) located near screen edge surrounded by dark
background emulate significant partial heating at the bright part(s). In some cases, the thermal stress breaks the
panel. Luminous efficacy and heat radiation design affect the thermal stress.
4 Structure of measuring equipment
The system diagrams and/or driving conditions of the measuring equipment shall comply with
the structure specified in each item.
5 Standard measuring conditions
Measurements shall be carried out under the standard environmental conditions defined in
IEC 61988-2-1, i.e. at a temperature of 25 °C ± 3 °C, a relative humidity of 25 % to 85 % and
a pressure of 86 kPa to 106 kPa. PDP modules and PDP panels to be measured shall be kept
in off-state and in the environmental conditions until they reach the stable temperature. When
different conditions are used, these shall be noted on the report.
The standard reference atmosphere defined in IEC 61988-4, i.e. 25 °C and 101,3 kPa, is
applied.
6 Measuring methods
6.1 Ball drop strength
6.1.1 Purpose
The purpose of this method is to measure the impact strength of screen of a PDP module using
ball drop.
6.1.2 Measuring equipment
The following equipment shall be used:
a) ball;
NOTE 1 Three kinds of smooth steel balls with the weights of 5,6 g, 8,3 g and 533 g are used.
b) height scale; and
c) others when used.
NOTE 2 For example a drop guide, which is a straight plastic pipe, whose inner radius is larger than the radius of
ball, and has side holes at the drop heights, can be used.
6.1.3 Applicability
This measurement can be applied to PDP module and PDP panel. In the case that modules
use directly laminated filter, the modules should be measured with the directly laminated filter.
6.1.4 Measurement layout
The PDP module shall be set on a rigid table or a rigid floor with the screen upward and
horizontal avoiding free movement and vibration as shown in Figure 1, or Figure 2 by using
rigid spacers.
In the case of a PDP panel, the panel shall be set on a measurement base with the screen
upward and horizontal as shown in Figure 3, avoiding free movement and vibration. The
measurement base and the cushion sheets should be the chassis and the bonding
material(s)/adhesive sheets respectively, or well-defined ones. The details of the
measurement base and the sheets shall be noted on the report. Non-adhesive sheets may be
put on the adhesive sheets, avoiding free movement and vibration, when the sheets do not

61988-4-2 © IEC:2012 – 7 –
affect the measurement result. In the case of a panel on which a directly laminated optical
filter will be applied, the panel should be measured with the filter.
Hereafter in 6.1, the term “PDP module” means also PDP panel set on the measurement base
as shown in Figure 3.
A height scale shall be set to measure the drop height as shown in Figure 4. The measuring
layout applied shall be noted on the report with the details.

PDP module
Rigid table
Rigid floor
a) On rigid table
b) On rigid floor
IEC  651/12
NOTE The screen of PDP module is set in a horizontal plane and upward. In the case using direct laminated
optical filter, the module is measured with the filter.
Figure 1 – Setting of PDP module (side view)

PDP module
Spacer
Rigid table
Rigid floor
a) On rigid table
b) On rigid floor
IEC  652/12
NOTE The screen of PDP module is set in a horizontal plane and upward.
Figure 2 – Setting of PDP module using spacers (side view)

PDP panel
Cushion sheets, bonding material(s)
or adhesive sheets
Measurement base
Rigid table or floor
IEC  653/12
NOTE The screen of the PDP panel is set in a horizontal plane and upward. Non-adhesive sheets can be put on
the adhesive layer when the sheets do not affect the measurement result.
Figure 3 – Setting of PDP panel (side view)

– 8 – 61988-4-2 © IEC:2012
Height scale
Ball
h
Measuring point
PDP module
Rigid table or floor
IEC  654/12
Key
h drop height at which the ball is released
Figure 4 – Measuring layout of ball drop strength (side view)
6.1.5 Measuring point
The measurement shall be carried out at the specified 9 points or 5 points P (where i is 0 to 8
i
or 0 to 4) on the screen area as shown in Figure 5. The ball drop impact shall be applied in
the screen area and in the circle having a radius of 30 mm and a centre at each specified point.
When other measuring points are measured, it shall be noted on the report.
H/2
V/10
Screen area
P P P
1 5 2
r = 30 mm V/2
P P P
8 0 6
V
Impact area
V/10
P P P
7 3
H/10 H/10
H
IEC  655/12
NOTE P to P are measuring points. H and V are the horizontal and vertical width of the screen respectively.
0 8
Figure 5 – Measuring points
6.1.6 Ball and drop height
The weight of ball shall be selected from Table 1. The ball shall have a smooth and hard
surface made of steel. The weight of applied ball shall be noted on the report. Drop heights
for each ball are listed in Table 1.
The minimum drop height, at which no damage is expected, should be selected from the drop
height list in Table 1. When other kinds of ball and drop heights are applied, it shall be noted
Drop height
61988-4-2 © IEC:2012 – 9 –
on the report. When the drop height exceeds 1 m, a drop guide may be used. The drop guide
may be a straight plastic pipe, whose inner radius is larger than the radius of ball, and which
has side holes at the drop heights listed in Table 1. Some special protections from the
scattered broken glass pieces should be used especially near the maximum height.
Table 1 – Ball and drop height
Weight Diameter Drop height Maximum
mm height
φ
g mm
mm
5,58 11,1 100, 200, 300, 400, 500, 600, 700, 800, 900, 1 000, 1 100, 1 200, 1 500
1 300, 1 400 and 1 500
8,33 12,7 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 1 500
750, 800, 850, 900, 950, 1 000, 1 100, 1 200, 1 300, 1 400 and
1 500
533 50,8 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 200
160, 170, 180, 190 and 200
6.1.7 Measuring procedure
The PDP module shall be set in the standard measuring conditions. The measuring layout is
shown in Figure 4. The measurement shall be done as follows:
a) Set the drop-ball at the selected minimum drop height over the measuring point P .
b) Drop the ball in the circle at P from the drop height.
c) Catch the ball after the first impact, if possible, for preventing the second impact.
d) Observe the measuring point to find any damage by the impact.
1) When no damage is observed, repeat the measurement from a) increasing the drop
height until any damage is observed or the ball drop from the maximum height has
been done. When no breakage is occurred at the maximum height, it shall be noted on
the report e.g. “no breakage at maximum height 1 500 mm.”
2) When panel breakage occurs, record the breaking height on the report. The size of
broken area and the breakage shape should be recorded. Pictures of the broken area
may be included in the report.
e) Change the measuring point and repeat the measurement from a) until measurements of
all measuring points are finished. In the case that the size of broken area is large and/or
the drop impact is large, the panel strength of neighbouring area is usually decreased.
When the damage and/or the panel breakage affects the panel strength of next measuring
point, change to a new module and continue the measurement from the next measuring
point.
When another measuring procedure is applied, it shall be noted on the report.
6.2 Partial heating strength
6.2.1 Purpose
The purpose of this method is to measure the breaking thermal stress of a PDP panel by
partial heating.
6.2.2 Measuring equipment
6.2.2.1 List of measuring equipment
The following equipment shall be used:
a) rubber heater;
b) temperature control unit (including heater power source);

– 10 – 61988-4-2 © IEC:2012
c) thermometer;
d) thermal sensor (e.g. thermocouple); and
e) thermal insulators.
NOTE Paper cups are good thermal insulators for this measurement.
6.2.2.2 Rubber heater
A 200 mm × 200 mm sheet-type rubber heater is used for this measurement. The rubber
heater shall have properties as follows:
a) a square shape with the size of 200 mm × 200 mm;
b) a thickness below 10 mm;
c) good temperature uniformity;
d) maximum temperature limit of over 150 °C;
e) light weight; and
f) soft.
NOTE The rubber heater is usually made of silicone rubber.
The detail of applied rubber heater shall be noted on the report.
6.2.2.3 Temperature control unit, thermometer and thermal sensor
The temperature rise of rubber heater is controlled by the temperature control unit. The
temperature of the rubber heater shall be monitored by a built-in thermal sensor or a film-type
thermal sensor set on the heater. The variables of temperature control unit shall be preset for
smooth temperature rise in time of the heater.
The temperature of PDP panel should be measured using other film-type thermal sensor set
on the screen near the centre of the heating area or in the uniform temperature area as
shown in Figure 7. The connecting wire of the thermal sensor shall be thin enough not to
affect the temperature uniformity of the heating area. Unnecessary vibration and deformation
of the connecting wires shall be avoided for the stable measurement. As long as smooth
temperature rise is established, the thermal sensor set on the screen can be used also as the
temperature monitor of the control unit.
The accuracy of thermometer shall be checked before the measurement. The type of applied
thermal sensor shall be noted on the report with its detailed specification especially the
temperature accuracy.
6.2.3 Measuring environmental conditions
Standard measuring conditions shall be applied. Direct and/or fast air flow to the panel shall
be avoided. When other conditions are applied, they shall be noted on the report.
6.2.4 Measuring layout
The PDP panel shall be set on the thermal insulators with the screen upward and horizontal
as shown in Figure 6. The positions and the numbers of thermal insulators should be chosen
to avoid any obvious bend of the panel. The rubber heater shall be set at a side edge centre
of the screen of the panel, aligning the edge of the heater to the screen edge. One of the
thermal sensor s shall be set at a measuring position using heatproof adhesive tape, if
necessary, to fix the position of the thermal sensor for temperature measurement as shown in
Figure 7. If a rubber heater having no built-in thermal sensor is used, an external thermal
sensor should be mounted on the outer side of the heater for the temperature monitor of the
heater, using heatproof adhesive tape as shown in Figure 7. The position of the external
thermal sensor shall be determined to obtain smooth temperature rise. The connecting wire of

61988-4-2 © IEC:2012 – 11 –
the thermal sensor should be also fixed by heatproof adhesive tape. As long as smooth
temperature rise is established, the thermal sensor set on the screen can be used also as the
temperature monitor of the control unit. The applied measuring layout shall be noted on the
report.
Screen area
Rubber heater
Top view
PDP panel
Thermal insulators
Table
Side view
IEC  656/12
NOTE Paper cups can be used as the thermal insulators.
Figure 6 – PDP panel setting
Connecting wire to temperature
control unit
Thermal sensors
Connecting wire
to thermometer
Heatproof adhesive tape
PDP panel
Screen edge
Rubber heater IEC  657/12
NOTE The side edge of the rubber heater is set at the screen edge. Adhesive tape can be put on the edges of the
rubber heater and on the thermal sensors used to improve the thermal contact between the heater and the panel
and to prevent the free movement of the thermal sensors.
Figure 7 – Setting of thermal sensor (sectional view)

– 12 – 61988-4-2 © IEC:2012
6.2.5 System diagram
The set-up of the measuring equipment is shown in Figure 8.

Temperature monitor
Temperature
control unit
Heater power source
Thermo sensors
Thermometer
PDP panel
Rubber heater
IEC  658/12
Figure 8 – Set up of measuring equipment
6.2.6 Measuring positions
The centres of all the side edges of the PDP panel shall be measured as shown in Figure 9.
Four panels are used for a set of measurement. Broken panels shall not be used for the
measurement. For each measurement, an edge of the rubber heater is aligned to the screen
area edge. When the measurement at the screen corners are defined on the relevant
specification, this method shall be modified and applied. When other position is measured, it
shall be noted on the report.
NOTE 1 Heat stress is caused by discharging a large area of pixels which creates a temperature difference
between the heat generating area and other area, i.e. bright area and surrounding area. As the heat generating
area is in the screen area, so a heating source, i.e. the rubber heater, is set in the screen area. The worst
condition is usually occurred at the panel edge, so the heater is aligned to the screen edge.
NOTE 2 Panel breakage caused by heat stress usually occurs near the edges of panels. The mechanism is as
follows. A small crack, e.g. a scratch, near the panel edge grows larger by the heat stress. The size of the crack
reaches a threshold at which the mechanical strength of the panel is reduced to the level of applied stress. Then
the panel breakage occurs.
P
Screen area
P
P
PDP panel
Position of rubber heater
P
IEC  659/12
NOTE P to P are the measuring positions.
1 4
Figure 9 – Measuring positions

61988-4-2 © IEC:2012 – 13 –
6.2.7 Heating rate and maximum temperature
Heating rate shall be between 1 °C/min and 5 °C/min. A heating rate of 3 °C/min is
recommended. A period in which temperature of a PDP panel driven with a still image in a set
reaches its stable temperature is usually around 30 min. It takes around 25 min the measured
panel reaches 100 °C from room temperature by the heating rate of 3 °C/min. The maximum
temperature of 150 °C is sufficient for normal use. The applied heating rate and the maximum
temperature shall be noted on the report.
6.2.8 Measuring procedure
The PDP panel shall be set in the standard measuring conditions. The room temperature shall
be recorded on the report. The measuring layout and the system diagram are shown in
Figures 6, 7 and 8.
The measurement shall be done as follows:
a) Set the rubber heater at the measuring position P .
b) Set the temperature control unit at a constant heating speed between 1 °C/min and
5 °C/min, and start the temperature rise from the room temperature.
c) Observe the panel temperature of heating area and continue the temperature rise until
panel breakage occurs or the temperature reaches the maximum temperature.
d) When panel breakage occurs, stop the power input to the heater immediately to avoid
extra heating of the heater. Record the breakage temperature and the difference between
the breakage temperature and the room temperature on the report.
d’) When the temperature reaches the maximum temperature, stop the temperature rise and
record the no breakage result on the report.
e) If panel breakage occurs, then change the PDP panel, set the rubber heater at other
measuring position, start the temperature rise and repeat the measurement from b) until
all positions to be measured are d
...