IEC TR 62908-1-3:2021

Touch and interactive displays - Part 1-3: Generic – General introduction to pen touch technology

IEC TR 62908-1-3:2021, which is a technical report, provides general information on pen touch technology with the aim toward standardization. This document includes an overview of the pen touch technology, critical performance characteristics, issues of characteristics measurements, and other information. The purpose of this documents is to provide an overview of the different products available in pen touch technology.

General Information

• Status: Published
• Publication Date: 27-Jul-2021
• ICS: 31.120 - Electronic display devices
• Technical Committee: TC 110 - Electronic displays
• Drafting Committee: WG 9 - TC 110/WG 9
• Current Stage: PPUB - Publication issued
• Start Date: 28-Jul-2021
• Completion Date: 02-Sep-2021

Standards Content (Sample)

IEC TR 62908-1-3 ®
Edition 1.0 2021-07
TECHNICAL
REPORT
colour
inside
Touch and interactive displays –
Part 1-3: Generic – General introduction to pen touch technology
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IEC TR 62908-1-3 ®
Edition 1.0 2021-07
TECHNICAL
REPORT
colour
inside
Touch and interactive displays –

Part 1-3: Generic – General introduction to pen touch technology

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 31.120 ISBN 978-2-8322-1009-2

– 2 – IEC TR 62908-1-3:2021 © IEC 2021
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms, definitions and abbreviated terms . 7
3.1 Terms and definitions . 7
3.2 Abbreviated terms . 7
4 Generic information on pen touch technology . 8
4.1 General . 8
4.2 Classification . 8
4.3 Sensing technology for touch pen . 9
4.3.1 General . 9
4.3.2 Resistive type panel structure and sensing method . 10
4.3.3 Capacitive type panel structure and sensing method . 10
4.3.4 EMI type panel structure and sensing method . 11
4.3.5 Optical type panel structure and sensing method . 12
4.3.6 Ultrasonic type panel structure and sensing method . 12
4.4 Touch pen architecture . 13
4.4.1 General . 13
4.4.2 Passive stylus pen . 13
4.4.3 Active stylus pen . 14
5 Pen touch characteristics . 17
5.1 General . 17
5.2 Basic characteristics of pen touch . 18
5.3 Unique and important characteristics of pen touch . 18
5.3.1 General . 18
5.3.2 Tracking speed . 19
5.3.3 Writing comfort . 19
5.3.4 Position parallax . 19
5.3.5 Minimum area and minimum pressure . 20
5.3.6 Pressure sensitivity . 20
5.3.7 Tilt angle . 21
6 Application example for each pen touch technology . 21
6.1 General . 21
6.2 Passive stylus pen . 21
6.3 Active stylus pen . 21
6.3.1 General . 21
6.3.2 EMI pen . 21
6.3.3 Universal pen for PCAP type . 22
6.3.4 Type MPP . 22
6.3.5 Type AP . 23
6.3.6 Type WA Active ES stylus. 23
6.3.7 Type U (multiple use) . 23
7 Issue of future pen touch technology . 23
7.1 General . 23
7.2 Tracking speed . 23

7.3 Writing comfort . 24
7.4 Combinational use of finger and pen touch . 24
7.5 Palm rejection area and pen positional relationship . 24
8 Collaboration of hardware and software . 25
Bibliography . 26

Figure 1 – Resistive Type Panel Structure . 10
Figure 2 – Capacitive type panel structure . 11
Figure 3 – EMI type panel structure . 12
Figure 4 – Optical type panel structure . 12
Figure 5 – Ultrasonic type panel structure . 13
Figure 6 – Example of conductive fibre tip . 14
Figure 7 – Example of transparent disk tip . 14
Figure 8 – Example of exclusive pen . 14
Figure 9 – Example of EMI pens (Type WE) . 15
Figure 10 – Position parallax . 20
Figure 11 – Pen tablet for animation/illustration . 22
Figure 12 – Examples of note PCs . 23

Table 1 – Comparison among pointing devices . 8
Table 2 – Classification of touch pen . 9
Table 3 – Correspondence between touch panel and touch pen . 10
Table 4 – Performance comparison of touch pens for PCAP/EMI . 17
Table 5 – Basic pen touch characteristics . 18
Table 6 – Unique and important characteristics of touch pen . 18

– 4 – IEC TR 62908-1-3:2021 © IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
TOUCH AND INTERACTIVE DISPLAYS –

Part 1-3: Generic – General introduction to pen touch technology

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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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.
IEC TR 62908-1-3 has been prepared by IEC technical committee 110: Electronic displays. It
is a Technical Report.
The text of this Technical Report is based on the following documents:
Draft Report on voting
110/1311/DTR 110/1331/RVDTR
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 Technical Report 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/standardsdev/publications.
A list of all parts in the IEC 62908 series, published under the general title Touch and
interactive 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,
 replaced by a revised edition, or
 amended.
IMPORTANT – The "colour inside" logo on the cover page of this document indicates that it
contains colours which are considered to be useful for the correct understanding of its
contents. Users should therefore print this document using a colour printer.

– 6 – IEC TR 62908-1-3:2021 © IEC 2021
INTRODUCTION
With the spread of smartphones in recent years, finger touch technology has become
widespread throughout the world. The field of popularization has started from smartphones,
and has spread from information terminals such as notebook (laptop) PCs and tablets to
kiosks, ATMs, sales equipment in the field of social infrastructure, medical equipment for
professional use, and construction-related items.
Finger touch has several challenges, such as malfunction due to usage environment, such as
wearing of gloves or water droplets, in addition to the difficulty of fine drawing with finger
touch, signature input, and so on.
Initially, for the pen touch, the operating system and application software supported only the
same function as finger touch, but recently a new concept of digital ink has enabled to use not
only the data of the entered trajectory, but also the progressing data such as writing pressure,
pen angle and drawing, being digitized and saved together with the trajectory data. This
means that a new technique with pen input has been developed, which goes beyond the
conventional technology of finger touch input.
Based on the above situation, this document aims to focus on the issues related to future
standardization by summarizing the sensing methods of pen touch, the types of touch pens
and the corresponding technologies, and the market trends of pen touch technology.

TOUCH AND INTERACTIVE DISPLAYS –

Part 1-3: Generic – General introduction to pen touch technology

1 Scope
This part of IEC 62908, which is a technical report, provides general information on pen touch
technology with the aim toward standardization. This document includes an overview of the
pen touch technology, critical performance characteristics, issues of characteristics
measurements, and other information.
The purpose of this documents is to provide an overview of the different products available in
pen touch technology.
NOTE The companies and products named in this document do not constitute an endorsement by IEC of these
products.
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 60068-1, Environmental testing – Part 1: General and guidance
IEC 62908-1-2, Touch and interactive displays – Part 1-2: Generic – Terminology and letter
symbols
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60068-1 and
IEC 62908-1-2 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
3.2 Abbreviated terms
AES Active electrostatic
AP Apple pencil
API Application program(ing) interface
AR/VR Augmented reality / virtual reality
ATM Automated [automatic] teller machine
DSC Digital Stationery Consortium
EMI Electromagnetic induction
– 8 – IEC TR 62908-1-3:2021 © IEC 2021
EMR Electromagnetic resonance
ES Electrostatics
IC Integrated circuit
MPP Microsoft Pen Protocol
OS Operating system
PCAP Projected capacitive touch panel
SDK Software developer's kit
SNR Signal to noise ratio
USI Universal Stylus Initiative
WA Wacom AES
WE Wacom EMR
4 Generic information on pen touch technology
4.1 General
In Clause 4, the classification of pen types, the corresponding sensing technology, and the
touch panel structure and principle are described.
4.2 Classification
To clarify the performance of the touch pens, a comparison is made between a finger touch, a
pen touch, and a mouse as a pointing device, as shown in Table 1.
The first major difference is that the finger touch and pen touch specify the absolute position
of the screen, but the mouse specifies the relative position of the screen, because it operates
at a different place from the screen.
The next point is regarding the accuracy of the position. The pen touches directly a specific
position of the screen, so the pen touches have the highest position accuracy. The second
highest accuracy is the mouse, because the mouse can control the precise position, and the
lowest accuracy is the finger touch, because the point area of a finger is larger than a certain
area on the screen.
On the other hand, the finger touch is suitable for multi-point designation and intuitive gesture
motion.
In addition, as a pen is a general writing tool, the pen touch is most suitable for drawing
pictures and signs, and also most suitable for manual input letters without using a keyboard.
Table 1 – Comparison of pointing devices

Finger Pen Mouse
Coordinates Absolute coordinates Absolute coordinates Relative coordinates
Positional accuracy Poor Excellent Fair
Multi points Available Available N.A.
Gesture operation Excellent Fair Poor
Drawing performance Fair Excellent Poor
Conformance of the signature Fair Excellent Poor
Compatibility with digital ink N.A. Available N.A.

Next, the types of touch pens can be classified as shown in Table 2. In Table 2 the first
category is whether the pen has an electrical circuit or not. The next category is about the
method of detecting the pen touch. In the third category, there are two types, one-way
communication (unidirectional) and two-way communication (bidirectional) with the pen and
the detection panel or the system side.
Table 2 – Classification of touch pen
Circuits Pen touch sensing 1 Unidirectional or
Pen type/ protocol
method bidirectional
built-in or not
Passive pen Resistive General commercial pen Unidirectional
(without circuits)
PCAP General commercial pen Unidirectional
Active pen PCAP Type MPP Bidirectional
(built-in circuits)
Type WA Bidirectional
Type AP Bidirectional
Type USI Bidirectional
Universal pen Bidirectional
EMI Old type Bidirectional
Type WE Unidirectional
Optical Exclusive Bidirectional

The active stylus pen which supports the PCAP touch panel is most in use for smartphones,
tablets, and note PCs. Some companies have recently developed their own methods which
compete with each other.
The optical pen is developed exclusively for a specific system, and there are many types, but
in this document the detailed technology is omitted.
4.3 Sensing technology for touch pen
4.3.1 General
There are two types of panel structure for the sensing pen touch:
1) Use of the touch panel sensing method (resistive type, capacitive type, optical type, or
ultrasonic type).
2) Use of the additional digitizer panel sensing method (EMI method).
Table 3 summarizes the relationship between the touch panel system and the touch pen.
In 4.3.2 to 4.3.6, the structure of each touch panel and the detection method are described.
___________
Microsoft Pen Protocol, Apple Pencil, Wacom AES and Wacom EMR are examples of suitable products
available commercially. This information is given for the convenience of users of this document and does not
constitute an endorsement by IEC of these products.

– 10 – IEC TR 62908-1-3:2021 © IEC 2021
Table 3 – Correspondence between touch panel and touch pen
Type Resistive Capacitive Optical Ultrasonic EMI panel
panel panel panel panel
Passive stylus Mainly used Mainly used Available Available N.A.
pen
Active stylus Available Mainly Used Available N.A. N.A.
pen
EMI pen Available N.A. N.A. N.A. Mainly used
NOTE 1 An electronic circuit is not included in the "passive stylus pen" (e.g., resonant circuits).
NOTE 2 Depending on the material of the passive stylus pen, detection can be by an optical method or an
ultrasonic method.
NOTE 3 Active stylus pens are generally made for capacitive type panel.
NOTE 4 There are also special pens for specific products on the market.

4.3.2 Resistive type panel structure and sensing method
The resistive type touch panel, which is shown in Figure 1, is configured with two resistive
films and a gap between these films.
By "pressing" the top resistive film with a finger or a pen, the pressed position is electrically
short-circuited. The driving and controlling IC detects this short-circuited position by
measuring the resistance value of this resistive film.
The pen has sufficient rigidity to short the two layers of resistive film electrically.

Figure 1 – Resistive type panel structure
4.3.3 Capacitive type panel structure and sensing method
The capacitive type panel, which is shown in Figure 2, has a structure in which two types of
electrodes are arranged in a matrix.
Since the two types of the adjacent electrodes are capacitively coupled, and the capacitive
component of the human body changes a parasitic capacitance of the point where a finger or
a pen touches, then the drive circuit detects this point.
In the case of the passive stylus pen, this pen needs the conductivity in order to transfer the
parasitic capacitance of the human body to the touch panel.
In the case of the active stylus pen, it has a built-in circuit to change the electric field
generated by the touch panel at a similar level as that of the finger touch. This touch pen has
a conductivity that can transmit a sufficient signal to the touch panel. In addition, there are

various structures forming the two types of adjacent electrodes on one substrate, for example
electrodes are formed on two pieces of glass or film.

Figure 2 – Capacitive type panel structure
4.3.4 EMI type panel structure and sensing method
As shown in Figure 3, the EMI panel structure has a plurality of rectangular antenna coils
arranged in parallel in a two-dimensional (X-axis, Y-axis) direction orthogonal to each other.
The detection method of the digitizer uses the electromagnetic induction between a plurality
of antenna coils stretched around the digitizer panel and a touch pen.
As shown in Figure 3 a), the initial touch pen has a transmitter coil, a power supply for
continuously generating an alternating magnetic field from the coil, a driver circuit, and an
oscillator circuit.
The digitizer's main body sequentially changes the switch of the antenna coil to scan the
sensor panel surface. The position of the touch pen was calculated by using the signal level.
Where the touch pen is closest to the panel, the strongest signal is detected from the antenna
coil, and a relatively weak signal is from the coil adjacent to the pen.
Further, information such as the switch data of the touch pen and the writing pressure has
been sent to the digitizer's main body by modulating the response signal from the touch pen
side by changing the capacity inside the touch pen.
In recent years, the "penable technology type digitizer" (see Figure 3b) WE type) has been
commercialized and occupies the market. In this method, the touch pen has no power source,
and the position is detected by exchanging electromagnetic energy between the touch pen
and the antenna coil of the digitizer body. [1]
___________
Numbers in square brackets refer to the Bibliography.

– 12 – IEC TR 62908-1-3:2021 © IEC 2021

a) Original type b) WE type
Figure 3 – EMI type panel structure
4.3.5 Optical type panel structure and sensing method
There are various types of optical touch panels, such as a scanning type, a projection type,
and an image (camera) type. Among them, a scanning panel structure will be described as a
typical example. This type panel has a structure in which a light emitting element array and a
light receiving element array are arranged as a set on opposite sides, as shown in Figure 4.
As for the detection method, the optical touch panel detects the position by shading the light
at the place where the pen hits.

Figure 4 – Optical type panel structure
4.3.6 Ultrasonic type panel structure and sensing method
In the structure of the ultrasonic touch panel, as shown in Figure 5, ultrasonic transmitters
and receivers are arranged on adjacent sides. The ultrasonic waves transmitted from each
side are sequentially reflected by Reflector 1 at 90° from the side closer to the transmitter Y in
Figure 5, and propagate to the panel. The ultrasonic wave received from the panel is reflected
by Reflector 2 at 90° and propagates to the receiver in sequence.
In the vicinity of the Y transmitter, the ultrasonic wave will be immediately reflected by
Reflector 1 at 90°, after being propagated to the panel; it will be again reflected at 90° by
Reflector 2 near the Y receiver, and will be received by the Y receiver in a short time after
transmission.
In an area far away from the Y transmitter, the propagation distance inside Reflector 1 and 2
becomes long, and t
...