IEC 62715-6-22:2026

IEC 62715-6-22 ®
Edition 2.0 2026-06
INTERNATIONAL
STANDARD
REDLINE VERSION
Flexible displays devices -
Part 6-22: Mechanical test methods - Crease and waviness measurement
methods for foldable displays
ICS 31.120 ISBN 978-2-8327-1307-5
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CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms, definitions and abbreviated terms . 6
3.1 Terms and definitions. 6
3.2 Abbreviated terms . 7
4 Standard atmospheric conditions . 7
5 Preparation of specimen for measurement . 7
5.1 General . 7
5.2 Visual examination . 7
5.3 Specimen preparation . 8
5.4 Measurement location . 11
5.4.1 General . 11
5.4.2 Crease . 11
5.4.3 Waviness . 11
6 Measurement methods . 12
6.1 General . 12
6.2 Purpose . 13
6.3 Non-contact topography . 13
6.3.1 General . 13
6.3.2 Test apparatus . 13
6.3.3 Measurement procedure . 17
6.3.4 Data analysis and report . 17
6.4 Non-contact profilometry . 21
6.4.1 General . 21
6.4.2 Test apparatus . 21
6.4.3 Measurement procedure . 23
6.4.4 Data analysis and report . 23
6.5 Contact profilometry . 24
6.5.1 General . 24
6.5.2 Test apparatus . 24
6.5.3 Measurement procedures . 26
6.5.4 Data analysis and report . 27
Bibliography . 28

Figure 1 – Step 1: Preparing the components of the specimen . 8
Figure 2 – Step 2: Turning the back of the panel to face upward . 9
Figure 3 – Step 3: Turning over the base plate and attaching it to the back of the panel . 9
Figure 4 – Step 4: Turning over the base plate with the panel attached . 10
Figure 5 – Example of crease and waviness measuring area . 12
Figure 6 – Example of measurement system . 14
Figure 7 – Analysis flowchart for PMD . 14
Figure 8 – Surface normal vector N, sight ray of a camera p and reflected ray r . 15
Figure 9 – Osculating circle and curvature . 16
Figure 10 – Example of data distribution in the crease measuring area . 17
Figure 11 – Example of data grouping on the vertical direction with folding axis. 18
th
Figure 12 – Example of the N profile data . 18
Figure 13 – Example of data distribution in the waviness measuring area . 20
Figure 14 – Concept of filtering profile . 20
Figure 15 – Schematic of the result of laser scanning . 21
Figure 16 – Schematic diagram of the laser scanning apparatus . 22
Figure 17 – Example of position 1 and position 2 in the crease measuring area . 23
Figure 18 – Schematic diagram of the contact profilometry apparatus . 25
Figure 19 – Schematic diagram of the motion of probe. 25

Table 1 – Example of specimen preparation condition. 11
Table 2 – Example of crease data report using the PMD method . 19
Table 3 – Example of reporting waviness data . 21
Table 4 – Example of laser scanning apparatus condition . 23
Table 5 – Example of reporting crease data by the laser scanning method . 24
Table 6 – Example of stylus condition . 26

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Flexible displays devices -
Part 6-22: Mechanical test methods -
Crease and waviness measurement methods for foldable displays

FOREWORD
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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This redline version of the official IEC Standard allows the user to identify the changes made
to the previous edition IEC 62715-6-22:2023. A vertical bar appears in the margin wherever a
change has been made. Additions are in green text, deletions are in strikethrough red text.

IEC 62715-6-22 has been prepared by IEC technical committee 110: Electronic displays. It is
an International Standard.
This second edition cancels and replaces the first edition published in 2023. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) addition of multiple-folding;
b) addition of new data analysis logic.
The text of this International Standard is based on the following documents:
Draft Report on voting
110/1841/FDIS 110/1852/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts in the IEC 62715 series, published under the general title Flexible 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 webstore.iec.ch in the data related to the
specific document. At this date, the document will be
– reconfirmed,
– withdrawn, or
– revised.
INTRODUCTION
The market for foldable display devices is growing rapidly, as shown in the new form factors for
portable devices. It is expected that various foldable display devices will be released in the near
future.
Typically, the cover for rigid displays is made of glass. A rigid glass cover protects the display
panel from external shock and produces a surface uniformity without visual distortion. In order
to utilize a foldable display, a thin and flexible cover is preferred rather than the thick general
rigid cover. Although cover materials like thin films or plastics can be flexible, their surface is
rougher and can crease more easily. Based on this expectation, there is an anticipation to
standardize the measurement of surface creasing and waviness due to folding in order to
evaluate the surface quality of foldable displays.
There is a wide variety of ways to analyse the surface of an object, and many of them are
already standardized, [1] to [9] . In this document, two of the non-contact methods and one
contact method using a probe are described, and the manner in which to report the values of
crease and waviness of foldable displays from the measured data is specified.

___________
Numbers in square brackets refer to the Bibliography.
1 Scope
This part of IEC 62715 specifies the standard measurement conditions and methods for
determining the surface crease and waviness for the evaluation of foldable displays. The
measurement methods are used to specify the extent of geometrical distortions in foldable
display surfaces. This document applies to foldable display panels and modules (e.g. in-folding
and out-folding) with one axis. If the foldable display panel has two or more folding axes, this
document applies only to the case that folding axes are parallel.
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 60050-845, International Electrotechnical Vocabulary (IEV) - Part 845: Lighting (available
at http://www.electropedia.org)
IEC 62341-1-2, Organic light emitting diode (OLED) displays - Part 1-2: Terminology and letter
symbols
IEC 62341-6-2:2015, Organic light emitting diode (OLED) displays - Part 6-2: Measuring
methods of visual quality and ambient performance
IEC 62715-5-3, Flexible display devices - Part 5-3: Visual assessment of image quality and
defects
IEC 62715-6-1, Flexible display devices - Part 6-1: Mechanical test methods - Deformation tests
ISO 4287, Geometrical Product Specifications (GPS) - Surface texture: Profile method - Terms,
definitions and surface texture parameters
ISO 16610-21, Geometrical product specifications (GPS) - Filtration - Part 21: Linear profile
filters: Gaussian filters
ASME B46.1-2019, Surface Texture (Surface Roughness, Waviness, and Lay)
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 62341-1-2 and
IEC 60050-845 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
– IEC Electropedia: available at https://www.electropedia.org/
– ISO Online browsing platform: available at https://www.iso.org/obp
3.1.1
crease
permanent or temporary linear visual distortion or deformation in the screen due to folding
3.1.2
waviness
long wavelength variation in a surface away from its basic form
Note 1 to entry: Within small areas of the display, distortions can occur in what should be nominally straight features
in images, characters, and symbols. This measurement characterizes the deviations from straightness.
3.1.3
folding area
curved section of the panel due to folding
3.2 Abbreviated terms
CCD charge-coupled device
CMM coordinate measuring machine
CMOS complementary metal-oxide semiconductor
DUT device under test
LIDAR light detection and ranging
PMD phase measuring deflectometry
PSD position sensitive detector
4 Standard atmospheric conditions
The standard atmospheric conditions specified in IEC 62715-6-1 shall apply as follows, unless
otherwise specifically agreed between customer and supplier:
– temperature: 25 °C ± 3 °C
– relative humidity: 25 % RH to 85 % RH
– atmospheric pressure: 86 kPa to 106 kPa
The temperature and humidity conditions shall be reported.
5 Preparation of specimen for measurement
5.1 General
In this document, the measurement object is called specimen, and the specimen consists of a
foldable panel, modules, adhesive, base plate and jig. The description of the specimen's
components and how to configure them is specified in 5.3. All measurements shall be performed
under non-operating conditions.
5.2 Visual examination
The foldable display panel is subjected to visual and dimensional checks under non-operating
conditions and a functional check under operating conditions specified as follows:
a) non-operating conditions: visual damage on the surface of the specimen shall be checked;
b) operating conditions: visual assessment shall be done by the methods specified in
IEC 62715-5-3.
Unless otherwise specified, Visual examination shall be performed under the conditions and
methods specified in IEC 62341-6-2:2015, 5.2.2.1, unless otherwise specifically agreed
between customer and supplier.
NOTE The purpose of 5.2 is to check the surface damage or failure of the DUT before performing the measurement.
5.3 Specimen preparation
The conditions for the preparation of the specimen (e.g. plate, jig), the number of cyclic folding
tests, the folding duration time, and the size of the specimen shall be determined between the
supplier and customer. If a mechanical test (e.g. cyclic folding test) is performed in the process
of preparing the specimen, the mechanical test method and condition shall be determined
between the supplier and customer before the preparation of the specimen. This mechanical
test specified in IEC 62715-6-1 and the test method and condition shall be reported.
NOTE 1 If the mechanical test is not performed in the process of preparing the specimen, the corresponding content
in Table 1 will be empty.
The temperature, humidity, storage time prior to testing, and the delayed time between the
specimen preparation and measurement can affect the crease and waviness, so the specimen
preparation condition and delayed time shall be controlled and reported.
NOTE 2 If the foldable display panel is unfolded and the time is delayed, the measurement result of the crease and
waviness can be smaller or alleviated due to the resilience of the panel. Therefore, the delayed time will be reported
as illustrated in Table 1.
The order and process of preparing the specimen are described as illustrated in Figure 1,
Figure 2, Figure 3, and Figure 4.
Step 1: Preparing the components of the specimen: the foldable display panel should be
unfolded after a specific duration under the conditions outlined in Table 1. The base plate shall
be flat and larger than the foldable display panel. The jig with a flat surface should be fixed to
the base plate and have an adhesive on the top to attach to the back of the panel. The panel
holder is used to prepare the out-folding type panel. It is a tool to maintain the flatness of the
panel while the jig is attached to the back of the panel in step 2 and step 3. The height of the
panel holder should be high enough sufficient to ensure that the folding area does not touch
the ground when the out-folding type panel is placed on it. When the foldable panel has N
folding axes, N+1 sets of jig/adhesive/panel holder are required. Figure 1 is an example of the
components for a specimen with two folding axes.
NOTE 3 Once the jig and the panel are attached, the panel holder is no longer necessary.

Figure 1 – Step 1: Preparing the components of the specimen
Step 2: Turning the back of the panel to face upward: the method and location of the attachment
should not affect the measurement. In order to eliminate the influence of tensile tension that
can occur in the process of attaching the panel to the jig, the foldable panel shall be flipped so
that the back of the panel faces upward. In other words, as shown in Figure 2, the light-emitting
surface of the panel is placed downward. It shall be placed on the panel holder and the folding
axis is positioned between the panel holders.
Figure 2 – Step 2: Turning the back of the panel to face upward
Step 3: Turning over the base plate and attaching it to the back of the panel: the base plate
shall also be flipped so that the adhesive surface faces downward. Then, lower the base plate
from the top down and attach it to the back of the panel. The folding axis should be located in
the centre between the jigs as shown in Figure 3.

Figure 3 – Step 3: Turning over the base plate and attaching it to the back of the panel
Step 4: Turning over the base plate with the panel attached: when the base plate with the
foldable panel attached is turned over, the top of the panel to be measured faces upward and
the specimen preparation is complete, as shown in Figure 4.

Key
a length of jig
b height of jig
c unattached area
d width of jig
Figure 4 – Step 4: Turning over the base plate with the panel attached
The description of each element is as follows:
– a should be longer than the width (length of y-axis) of the foldable display panel;
– b should be high enough that the folding area does not touch the base plate. It can be
affected by the folding radius;
– c should include one folding axis, so if there are N folding axes in the panel, N unattached
areas are made. The minimum value of c should be at least 10 times the foldable panel's
bending radius or higher.
NOTE 4 To measure the crease, a folding area is located in the unattached area c and the measurement location
will include the unattached area c. The folding area depends on the foldable panel's bending radius. The minimum
range of the folding area will be a value obtained by multiplying the bending radius by pi (π). Therefore, to prevent
the effects of the fixation of the adhesive on the crease measurement, the unattached area will be at least 10 times
the foldable panel's bending radius.
– d should not intrude the folding area, and it should support the foldable display panel to
keep it flat.
The values of c and d shall be determined by the supplier and customer and reported.
The measurement object should be a specimen which consists of the foldable panel fixed on
the jig and base plate for reproducibility of the measurement. It is also a similar condition to the
foldable panel inserted in the foldable device. However, the attachment method which consists
of adhesive fixing while preparing specimen should not affect the measurement. In the process
of attaching, it is necessary to attach the panel to the jig with the panel turned over to prevent
the forcible pulling of the panel. This is described in step 2 and step 3, and the attachment
method shall be reported. In the process of measuring the completed specimen after attachment,
care should be taken to measure the original waviness of the panel, not the waviness of the
adhesive or jig. It should also be noted that only the data of the specimens obtained under the
same conditions be compared so that the various factors such as thickness, type, size and
location of adhesive and jig used in the specimen preparation do not affect the data.
An example of reporting the items for specimen preparation described in 5.3 is shown in Table 1.
Table 1 – Example of specimen preparation condition
Foldable
Base plate Folded storage condition
panel
1. Before 2. Folded state storage
3. Unfolded
Unattached
Specimen folding condition
area (c)
no.
Attachment Bending
Mechanical
(≥ 10 times
method radius
test Storage Delayed
the bending
Temp. Humidity
(type/ time time
radius)
number)
Adhesive Cyclic 25 °C ±
1 20 mm 85 % 24 h 15 min 2 R
tape folding/100 3 °C
If a specimen is ready, particles should be removed from the surface before the measurement,
using an appropriate cleaning method for the specimens, for example compressed air, wiping
with isopropyl alcohol, using an anti-static gun, etc.
5.4 Measurement location
5.4.1 General
Crease and waviness measurements can be taken at several specified locations on the surface
of the foldable display panel. If there are multiple measuring areas in one specimen, the location
and the size of each measuring area shall be reported. The height and width of the measuring
area shall be determined by the supplier and customer. Figure 5 is an example of crease and
waviness measuring area in the foldable display panel with two folding axes.
5.4.2 Crease
A folding area which is the curved section of the foldable display panel due to folding shall be
located in the measuring area. This folding area should be located at the centre of the crease
measuring area. Figure 5a) is an example of the crease measuring area in the foldable display
panel.
A folding area shall be located at the centre of the crease measuring area, and only one folding
area shall be included in one measuring area.
5.4.3 Waviness
The measuring area of waviness shall not include an unattached area (c, having a value of
10 times the foldable panel's bending radius or higher, as described in 5.3). In other words, the
measuring area shall be designated from the point at which it is at least 5 times the foldable
panel's bending radius away from the folding axis so that unattached area and waviness
measuring area do not overlap. Figure 5b) is an example of the waviness measuring area in the
foldable display panel.
(a) Example of crease measuring area location (b) Example of waviness measuring area location

Figure 5 – Example of crease and waviness measuring area
6 Measurement methods
6.1 General
In this document, three types of methods are described for implementation:
a) a non-contact method in which a screen is used to measure the surface without contact;
b) a non-contact method using a laser;
c) a contact method in which a stylus contacts the surface for measurement.
The contact method can be used when the non-contact method cannot be performed (e.g. the
display surface becomes matte after applying an anti-glare film and the image is not reflected).
However, the contact method is not recommended since this method can damage the foldable
display surface.
The non-contact topography (see 6.3) can be adopted to measure both crease and waviness.
The non-contact profilometry (see 6.4) and contact profilometry (see 6.5) methods can be
adopted to measure crease. These three methods are one of many ways to analyse the surface
as described in the Introduction. It does not mean that other methods are excluded; these can
be selected by decision between the supplier and the customer. 6.3.4, 6.4.4 and 6.5.4 focus on
how to analyse the measured surface data and express it as crease and waviness of the foldable
display. Data comparisons shall be made between the data measured and analysed under the
same measurement method, environment, and conditions.
6.2 Purpose
The purpose is to measure the crease and waviness of the specimen which would appear in
actual usage. Due to the morphological and geometric changes of crease and waviness, several
issues can appear, such as luminance uniformity, viewing angle, and image distortion.
6.3 Non-contact topography
6.3.1 General
To measure crease and waviness the phase measuring deflectometry (PMD) method is used in
this document since PMD is the proper method to measure large sizes, as it is suitable for
measuring large areas and can yield highly accurate data [10]. The principle of PMD is to display
fringe patterns on a screen which is located far from the DUT, and to observe the fringe patterns
reflected via the surface of the DUT. Any slope variation of the surface of the DUT leads to
distortions of the pattern, so the PMD can measure the slope of the surface with high accuracy
(see [11], [12], [13]). From this measured slope data, the altitude and curvature can be derived
by integration and differentiation, respectively (see [14] and [15]). Altitude and curvature are
used to represent the crease and waviness, and the principle and data analysis are given in
detail in 6.3.2 and 6.3.4.
6.3.2 Test apparatus
Figure 6 shows an example of a measurement system based on PMD. The main devices for
PMD include an imaging device (e.g. charge-coupled device (CCD), digital camera), a screen
(e.g. TFT-LCD monitor) and a computer. Computer-generated fringe patterns are sequentially
displayed on the screen, and the screen shall be flat and sufficiently large so that it can project
on the surface of the DUT without distortion. The patterns displayed on the screen in the PMD
are typically sinusoidal fringes which are smooth intensity curves, and the phase calculation is
not very sensitive to a small amount of out-of-focus effect. The camera captures the reflection
of the patterns displayed on a screen through the surface of the DUT (see [10], [14], [15]). Since
PMD is a method of analysing changes between the reference pattern displayed on the screen
and the reflected image captured by the CCD, it is important to clearly detect the difference
between those two patterns.
Figure 6 – Example of measurement system
There are many academic papers that have conducted experiments by implementing the PMD
method described above (see [14], [16] to [19]).
An example of flowchart for the PMD process is given in Figure 7. After the distortions of the
pattern are captured and recorded, the fringe phases shall be retrieved by using the fringe
analysis method. The fringe analysis includes fringe demodulation (see [20] to [25]) and phase
unwrapping (see [26], [27], [28]) as shown in Figure 7.

Figure 7 – Analysis flowchart for PMD
Once the absolute phase values are retrieved, their location on the screen can be determined
since the period of the fringe pattern on the screen is a known parameter. Using the geometry
relations between the surface of the DUT and the camera, the slope of the local area on the
surface of the DUT is calculated by tracking the normal direction of the reflected ray at each
point on the surface of the DUT.

Figure 8 – Surface normal vector N, sight ray of a camera p and reflected ray r
For easier understanding and analysis, the sight ray of a camera is treated as the light source
in the PMD although the light is actually illuminated from the screen. Surface normal N can be
calculated from the normalized vector of the sight ray of a camera p and reflected ray r. As
illustrated in Figure 8, the surface normal vector N can be determined by Formula (1):

N
x

N =-rp = N
(1)

y

N
z
where
N , N , N are the x-, y- , and z- components of the surface normal N.
x y z
The surface of the DUT's x- and y-slopes (S , S ) are therefore calculated as
x y
N
x
S =-
(2)
x
N
z
N
y
S =-
(3)
y
N
z
The altitude, which is the height distribution z, is reconstructed from the calculated coordinates
(x, y) and slopes (s , s ). This integration process can be expressed as
x y
z=ƒ x,,yS ,S (4)
( )
int2 x y
where
ƒ
( )
int2
is an integration function [6].
The altitude is calculated by the integration process of Formula (4) from the slope which is
calculated by Formula (2) and Formula (3). The difference between the minimum and maximum
value of this altitude can measure the crease depth and it can examine the profile of the overall
surface of the DUT. The data analysis of crease using this altitude is given in detail in 6.3.4.1.
 
dz dz
,
  (5)
 22
dx dy
 
The curvature is calculated by differentiation using Formula (5) from the slope which is
calculated by Formula (2) and Formula (3), and as mentioned in 6.3.1 the curvature can
represent the waviness. The meaning of the curvature to be used to indicate waviness is as
follows (see Figure 9):
a) Example of osculating circles b) Relation between R and κ
Figure 9 – Osculating circle and curvature
The curvature means the degree to which curves bend. When an osculating circle is defined at
the particular point of the surface, the curvature is an inverse number of the osculating circle
radius.
κ= (6)
R
where
κ is the curvature;
R is the radius of the osculating circle.
The smaller the curvature the larger the radius of the osculating circle, and the surface has a
gradual curve. Figure 9 b) shows the relation between the osculating circle radius and the
curvature. The data analysis of waviness using this curvature of the particular point of the
surface is given in detail in 6.3.4.2.
6.3.3 Measurement procedure
The screen, DUT and camera (CCD) are set as described in Figure 8. The screen size, distance
between the screen, and surface of the DUT depend on the DUT. The measurement shall be
performed as follows.
a) Prepare the required number of specimens in accordance with 5.3.
b) Load the specimen on the test apparatus.
c) Level and align the apparatus and specimen as follows:
1) the specimen should be aligned so that the vertical direction of the measuring area
(which is described in 5.4) and the folding axis of the foldable panel are parallel;
2) the specimen should be levelled relative to the apparatus' traverse unit. It means the
test apparatus is adjusted for tilt relative to the specimen until no significant relative tilt
is detected so that the Z value of the X-Y plane of the measuring area is zero.
d) Display the computer-generated sinusoidal fringe patterns on the screen and reflect the
fringe patterns on the surface of the DUT.
e) Capture the reflected image by camera (CCD) and record it.
f) Input the information on the phase difference and the geometry relation of the screen, DUT
and camera (CCD) location.
g) Calculate the slope of the local area data by the logic described in 6.3.2.
h) Data dropouts or noise that can occur during the measurement should be excluded by the
calibration system.
6.3.4 Data analysis and report
6.3.4.1 Crease
Crease shall be analysed as follows.
a) The surface slope of each local point is obtained as described in 6.3.3. Figure 10 shows an
example of this data distribution in the crease measuring area (H × V) which is determined
in 5.4, and measured by the CCD having M × N data resolution.

Figure 10 – Example of data distribution in the crease measuring area
b) Using the procedure described in 6.3.2, the M × N altitude values of each local point shall
be calculated using Formula (4) from the M × N surface slope values of each local point
obtained in a).
c) M × N altitude values can be grouped in the x-axis direction that is vertical with the folding
axis as shown in Figure 11; N data bundles are then obtained. One data bundle can be
drawn as a graph of the change in the z value according to the x value. Figure 12 shows an
th
example of the N row profile data.
Figure 11 – Example of data grouping on the vertical direction with folding axis

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Figure 12 – Example of the N profile data
d) Find the critical points where the sign of the profile slope changes among the M data points
that make up one data bundle. The range shall be limited to the unattached area, c,
described in 5.3. The example of critical points within the c range is shown in Figure 12, and
in this case, 10 critical points (P ~P ) are found. The area where jigs are attached to the
1 10
back of the panel can affect the measurement, so the data should be analysed within the
range of unattached area, c.
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e) In the N row profile graph, the C D value is defined as the difference between the
N N
maximum value of Z and the minimum value of Z among critical points. Figure 12 shows an
example of D , the difference between the Z values of P and P . It can be expressed as
N 6 7
follows:
D Max(ZZ)− Min( )
N NN
(7)
C = Max(Z ) − Min(Z )
N N N
f) C , C , … , C D , D , …, D will be obtained by e). The average of these values is defined
1 2 N 1 2 N
as the 'crease depth', C
d
=
C AVG(DD, , ,… D )
d 12 N (8)
C = AVG(C , C , … , C )
d 1 2 N
g) In order to obtain the distribution of crease depth data within measuring area, the standard
, C , … , C D , D , …, D values are defined as the 'SD of crease depth',
deviation of C
1 2 N 1 2 N
C
d,SD
C STDEV(DD, , …,D )
d,SD 1 2 N
(9)
C = STDEV(C , C , … , C )
d,SD 1 2 N
th
h) In the N row profile graph, the W value is defined as the difference between the X values
N
with the maximum value of Z and the minimum value of Z. It can be expressed as
Formula (10); Figure 12 also shows the meaning of W . The value multiplied by 2 by the
N
average of W , W , … , W will be defined as the 'crease width', C (11) at both ends of
1 2 N w
critical points within the range of unattached area. Figure 12 shows an example of W , the
N
difference between the X values of P and P . It can be expressed as follows:
1 10
WX −X
(10)
N Rightmost critical point Leftmost critical point

i) W , W , …, W will be obtained by h). The average of these values is defined as the 'crease
1 2 N
width', C .
w
C AVG(WW, , ,… W )
(11)
w 12 N
j) Report the 'crease data' results with the conditions such as measuring area, and CCD data
resolution. Table 2 shows an example of reporting crease data. As described in 5.3, since
the conditions of the specimen can affect the result value, the conditions specified in Table 1
shall be reported together with Table 2.
NOTE A gradient of crease can also be calculated by the ratio of the C C value obtained in Formula (8) to the
N d
W C value obtained in Formula (11), which means C C over W C . However, this value cannot represent the
N W N d N W
crease by itself because it is not enough to express the exact dimension of the crease form. Therefore, if the gradient
of crease is used as crease data, it will be reported together with the crease depth and crease width values of
Table 2.
Table 2 – Example of crease data report using the PMD method
Crease data
Measuring area
CCD data
SD of crease
resolution
(H × V) Crease depth Crease width
depth
80 mm × 60 mm 1 000 × 800 -
6.3.4.2 Waviness
Waviness shall be analysed as follows.
a) The surface slope of each local point is obtained as described in 6.3.3. Figure 13 shows an
example of data distribution in the waviness measuring area (H × V) which is determined in
5.4, and measured by the CCD having M × N data resolution.
=
=
=
=
Figure 13 – Example of data distribution in the waviness measuring area
b) Using the method described in 6.3.2, the M × N curvature values (κ, kappa) of each local
point shall be calculated by Formula (5) from the M × N surface slope values of each local
point obtained in a).
c) Determine the spatial sampling length range to separate the waviness profile from the
original profile. By using the profile filter, the curvature value of the desired wavelength
...