IEC 62899-302-1:2017

IEC 62899-302-1 ®
Edition 1.0 2017-08
INTERNATIONAL
STANDARD
colour
inside
Printed electronics –
Part 302-1: Equipment – Inkjet – Imaging based measurement of jetting speed
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IEC 62899-302-1 ®
Edition 1.0 2017-08
INTERNATIONAL
STANDARD
colour
inside
Printed electronics –
Part 302-1: Equipment – Inkjet – Imaging based measurement of jetting speed

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 19.080; 37.100.10 ISBN 978-2-8322-4683-2

– 2 – IEC 62899-302-1:2017  IEC 2017
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 Inkjet jetting speed measurement . 7
4.1 General . 7
4.2 Process for measurement of drop delivery speed (method 1) . 7
4.3 Process for measuring instantaneous jetting speed using single flash mode
(method 2) . 8
4.4 Process for instantaneous jetting speed curve (method 3) . 9
4.5 Process for measurement of instantaneous jetting speed using double flash
(method 4) . 9
Annex A (informative) Additional information on inkjet measurement methods . 11
A.1 Vision-based measurement hardware . 11
A.2 Flash imaging . 11
A.2.1 General . 11
A.2.2 Single event imaging . 11
A.2.3 Multiple event imaging . 11
A.3 Analysis method 2 (instantaneous jetting speed using single flash) . 12
A.4 Analysis method 3 (instantaneous jetting speed curve) . 13
A.5 Analysis method 4 (instantaneous jetting speed using double flash) . 15
A.6 Recorded operating parameters for drop speed measurements . 16
Bibliography . 18

Figure A.1 – Vision measurement method . 11
Figure A.2 – Two different trigger delays for two images . 12
Figure A.3 – Jetting speed measurements using two images . 12
Figure A.4 – Droplet locations in a droplet image . 13
Figure A.5 – Drop formation measurement . 14
Figure A.6 – Double flash using single jetting trigger. 15
Figure A.7 – Jetting speed measurement using double flash method . 16

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PRINTED ELECTRONICS –
Part 302-1: Equipment – Inkjet – Imaging based
measurement of jetting speed
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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2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62899-302-1 has been prepared by Technical committee 119:
Printed electronics.
The text of this standard is based on the following documents:
FDIS Report on voting
119/168/FDIS 119/183/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 document has been drafted in accordance with the ISO/IEC Directives, Part 2.

– 4 – IEC 62899-302-1:2017  IEC 2017
A list of all parts in the IEC 62899 series, published under the general title Printed electronics,
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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INTRODUCTION
Inkjet technology uses micro nozzles to precisely eject droplets. For printing, these droplets
are patterned on a substrate. Inkjet is a mature technology that has been used widely in home,
commercial, and industrial applications. When using inkjet technology, the volume of a droplet
can be controlled down to the tenth of a picoliter (pl). Furthermore, the droplet can be placed
onto the substrate with an accuracy of micrometers (µm). Because of these features and
others, inkjet technology has emerged as one of the most powerful tools for patterning
electronic devices, medical dispensing, high precision industrial applications, and more. Inkjet
patterning for electronics is an additive process wherein the addition of multiple layers of the
pattern does not require the removal of any previously deposited material, unlike the
conventional photolithography process. Inkjet also reduces waste when used in more
traditional printing applications and when it is used for dispensing. As a result, inkjet
technology significantly reduces waste of what are often very expensive materials and is also
more environmentally friendly.
As applications for inkjet broaden, a wider variety of jetting materials should be dispensed
precisely from inkjet heads. For both new and traditional applications, droplet behaviour from
the inkjet head should be measured properly to evaluate and control jetting behaviour. Vision-
based measurement techniques are widely used in inkjet-based manufacturing systems, since
physical insight into jetting behaviour can be obtained from visual images. The droplet jetting
speed and droplet volume are the most frequently measured jetting performance parameters
obtained from droplet images.
Using information obtained from vision-based measurement systems about inkjet droplet
formation and characteristics, developers can adjust ink formulations and jetting parameters,
in order to improve performance.
Note, however, that the measured jet performance and evaluation may vary considerably
according to the measurement method since there is no standard measurement procedure
available. It may be difficult for process engineers to judge the data sheets of jet performance
provided by ink and inkjet head manufacturers since there are no fair test methods, thus
causing potentially untrustworthy results. Therefore, the purpose of this document is to
provide a standard inkjet measurement method.

– 6 – IEC 62899-302-1:2017  IEC 2017
PRINTED ELECTRONICS –
Part 302-1: Equipment – Inkjet – Imaging based
measurement of jetting speed
1 Scope
This part of IEC 62899 specifies the method for determining inkjet drop speed based on
visualized droplet images obtained by a drop analysis system. This measurement
standardization is limited to drop-on-demand-type of inkjet and is not applicable to continuous
inkjet. This document includes the test process, image processing software algorithm, and
analysis of jetting behavior.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
inkjet printing
type of printing in which a digital image is created by propelling droplets of ink onto a
substrate
3.2
drop analysis system
vision-based equipment that can both image and measure inkjet droplets
3.3
drop speed
distance divided by the time it takes the drop to traverse the distance
3.4
drop delivery speed
total distance between the inkjet print-head nozzle plate and the substrate, divided by the
time interval between jet triggering and drop arrival
3.5
drop trajectory
drop’s direction of travel, often characterised as an angle relative to the nozzle plate
3.6
drop repeatability
droplet jetting behaviour whereby each drop ejected from the nozzle is the same as every
other
Note 1 to entry: Drop repeatability is often visualized by displaying individual drops, one per frame, so the
characteristics of each can be compared and contrasted. It is quantified by measuring the standard deviation of the
drops.
3.7
drop trace
plot of droplet locations from sequential images to understand jetting behaviour including
ligament and satellites
3.8
single event imaging
method of capturing each drop image that represents a single jetting event
Note 1 to entry: Raw images of individual drops are in no way added or averaged to produce the final image.
3.9
multiple event imaging
method of capturing each drop image that represents an average or sum of multiple jetting
events
Note 1 to entry: Raw images of individual drops are added or averaged to produce the final image.
3.10
single flash mode
LED or high power light that is flashed once per jetting event
Note 1 to entry: Single flash mode may be used with single- or multiple-event imaging.
3.11
double flash mode
LED or high power light that is quickly flashed twice per jetting event, thereby capturing the
same individual drop in two different locations within the camera field of view
Note 1 to entry: Double flash mode may be used with single or multiple event imaging.
3.12
sequential image
series of jetting images starting from the jetting trigger signal to the time of interest
Note 1 to entry: Sequential images can be obtained from the drop analysis system by increasing the trigger delay
of the flash with respect to jetting signal.
3.13
jetting speed curve
jetting speed plot with respect to time, which is calculated from the drop trace
Note 1 to entry: The information includes the relative jetting speed of the main droplet with respect to satellites.
4 Inkjet jetting speed measurement
4.1 General
Inkjet jetting speed shall be measured by using one of the following methods, unless there is
a user and supplier agreement. See Annex A for additional information on inkjet measurement
methods.
4.2 Process for measurement of drop delivery speed (method 1)
This process describes the measurement method for drop delivery speed from the time of the
jetting trigger to the time the drop reaches the target location.

– 8 – IEC 62899-302-1:2017  IEC 2017
1) Commence printing with the desired specifications (frequency, ink selection, waveform,
etc.). It is recommended to record the jetting conditions, in addition to those described in
Clause A.6.
2) Specify the target stand-off distance S from the nozzle surface, which usually corresponds
to the distance between the nozzle surface and the substrate.
NOTE Stand-off distances between 0,3 mm and 2,5 mm are typical.
3) Determine the time (T) for the leading edge of the droplet to reach the target stand-off
distance by increasing the delay time of the strobe light flash. This process may be
performed automatically, or manually. The duration of the flash should not be greater than
a few hundred nanoseconds to avoid image blur of the droplet. The flash intensity should
be sufficient to allow discrimination between the drop edge and the background, without
saturating the image.
4) The drop delivery speed V can be calculated as:

S
V= (1)
T
5) The calibration factor F (µm/pixel) should be determined at the optical magnification used
by the drop analysis system to determine drop delivery speed (m/s) from Formula (1). The
bottom locations of the droplet are used for the droplet location if the droplet has a long
ligament.
4.3 Process for measuring instantaneous jetting speed using single flash mode
(method 2)
This process describes the measurement method
...