IEC 62899-402-3:2021

IEC 62899-402-3 ®
Edition 1.0 2021-04
INTERNATIONAL
STANDARD
colour
inside
Printed electronics –
Part 402-3: Printability – Measurement of qualities – Voids in printed pattern
using a two-dimensional optical image
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IEC 62899-402-3 ®
Edition 1.0 2021-04
INTERNATIONAL
STANDARD
colour
inside
Printed electronics –
Part 402-3: Printability – Measurement of qualities – Voids in printed pattern

using a two-dimensional optical image

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 31.180 ISBN 978-2-8322-9671-4

– 2 – IEC 62899-402-3:2021 © IEC 2021
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms, definitions and abbreviated terms . 6
4 Atmospheric conditions for evaluation and conditioning . 7
5 Measuring methods and instruments . 7
5.1 Measuring instrument. 7
5.2 Preparation of specimen . 8
5.3 Measuring method . 8
5.4 Obtaining void-related attributes . 10
6 Report of results . 10
6.1 Measurement identification information . 10
6.2 Instrument system and its specification . 11
6.3 Sampling position . 11
6.4 Results . 11
Annex A (normative) Void threshold . 12
Annex B (normative) Additional attribute from measurement – Size distribution of
voids . 17
Bibliography . 18

Figure 1 – Definition of pattern area and background area in the ROI of the captured
image . 8
Figure 2 – Distribution of the brightness of the pixels of the pattern area and mean
value, and distribution of the brightness of the pixels of the background area and mean
value. 9
Figure 3 – Binarization of pattern and detected voids . 10
Figure A.1 – Different images of a void . 12
Figure A.2 – Dependence of the void threshold on the void threshold index . 12
Figure A.3 – Distribution of the brightness of pixels of the printed pattern and effect of
Z . 13
Figure A.4 – Example of void detection depending on Z . 14
Figure A.5 – Additional examples of void detection depending on Z . 15
Figure A.6 – Total numbers and areas of voids in the sample images of Figure A.4 and
Figure A.5 . 16
Figure B.1 – Size distribution of voids in the sample images of Figure A.3 or Figure A.4 . 17

Table 1 – Reporting items example . 11

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PRINTED ELECTRONICS –
Part 402-3: Printability – Measurement of qualities –
Voids in printed pattern using a two-dimensional optical image

FOREWORD
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International Standard IEC 62899-402-3 has been prepared by IEC technical committee 119:
Printed Electronics.
The text of this International Standard is based on the following documents:
FDIS Report on voting
119/346/FDIS 119/350/RVD
Full information on the voting for the approval of this International Standard can be found in the
report on voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 62899 series, published under the general title Printed electronics,
can be found on the IEC website.

– 4 – IEC 62899-402-3:2021 © IEC 2021
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INTRODUCTION
This document contains fundamental information on the measurement of voids in a printed
pattern in printed electronics. Void in this document is defined as a very small non-patterned
part of a printed pattern, caused by the printing condition and ink properties, and treated as
two-dimensional on a substrate. It can be seen that the terms void and pinhole used in the
electronics and graphic printing industries, and the term void used in this document are different.
There can be three kinds of absence of materials in the pattern. First, an absence of material
inside the solid pattern, which is generally called void in the electronics industry. In this case,
there is a vacancy inside the pattern but no imperfection area observed from a two-dimensional
(2D) top-view. Therefore, it cannot be defined in the graphic printing industry where only two-
dimensional (2D) images are meaningful. Second, there can be a hole penetrating from the
surface of the printing layer to the substrate. This case can be observed as a hole in the printing
area, and is called a pinhole in the electronics industry and a void in the graphic printing industry,
respectively. The third one is a deep hole that does not penetrate into the substrate, therefore
it is observed as a hollow in a 2D top-view of a printing image. In the electronics industry, this
case is called hollow or pit, and in the graphic printing industry, it is called hollow or void in
general. This document deals with the second and third cases, and focuses on the 2D image of
the printed pattern; therefore, the term void is used in this document according to the generally
used definition in the graphic printing industry. Voids should not exist in the printed patterns
which constitute the printed electronics devices to be commercialized for the stable and reliable
performance of the devices. The detection and analysis of voids in the pattern can provide
guidelines to evaluate the printability of the process, inks, and equipment, therefore, it is
possible to manage and control the performance of the printed electronics devices by measuring
and analysing the voids at the patterning process from the point of view of printability. An easy
way to detect voids in the printed pattern can be to use a three-dimensional (3D) prof
...