IEC TR 62977-2-4:2018

Electronic displays - Part 2-4: Transparent displays - Overview of application scenarios

IEC TR 62977-2-4:2018(E) provides a comprehensive overview of application scenarios for transparent displays of the two major display technologies (liquid crystal (LC) and organic light emitting diode (OLED) displays) and introduces the observation and illumination aspects that are taken into account for the establishment of appropriate measurement methods.

General Information

• Status: Published
• Publication Date: 12-Nov-2018
• ICS: 31.120 - Electronic display devices
• ICS: 31.260 - Optoelectronics. Laser equipment
• Technical Committee: TC 110 - Electronic displays
• Current Stage: PPUB - Publication issued
• Start Date: 13-Nov-2018
• Completion Date: 06-Nov-2018

Overview

IEC TR 62977-2-4:2018 is a Technical Report from the International Electrotechnical Commission (IEC) that provides a comprehensive overview of application scenarios for transparent displays. It focuses on the two major direct-view display technologies - liquid crystal (LC/LCD) and organic light emitting diode (OLED) - and introduces the observation and illumination aspects that must be considered when establishing appropriate measurement methods for transparent display performance.

Key topics covered

• Application scenarios and use cases for transparent displays (e.g., shop windows, showcases, refrigerator doors, AR overlays, head-up displays), distinguishing direct-view transparent displays from projection systems.
• Display technologies: the behaviour and implications of LCD (transmissive) and OLED (emissive) transparent displays.
• Performance aspects:
  • On-screen performance - visual information generated by emission (OLED) or transmission (LCD).
  • Through-screen (see-through) performance - visibility and contrast of objects/scenes behind the transparent display screen.
• Intended vs unwanted light contributions: classification of intended visual information and unwanted ambient contributions (reflections, transmitted background light) that reduce contrast and colour saturation.
• Measurement components and considerations (Section 5):
  • Spectral radiance
  • Object/scene characteristics
  • Display-specific parameters for emissive and transmissive devices
  • Practical precautions during measurements (e.g., effects of scattering, diffraction, haze, pixel fill-factor and ambient illuminance)
• Terminology and definitions relevant to transparent display testing (AR, on-screen contrast, through-screen contrast, TDS).

Practical applications and who uses this standard

This Technical Report is useful for:

• Display manufacturers and designers developing transparent OLED or LCD screens.
• Test laboratories and measurement engineers creating or validating measurement protocols for transparent display performance.
• Systems integrators and product engineers for retail signage, appliances (e.g., refrigerator doors), automotive and aerospace HUD concepts, and augmented reality (AR) device makers.
• Standards developers and policy makers seeking terminology and scenario-based guidance for further normative standards.

Practical value: the report helps stakeholders understand how ambient lighting and the interaction of scene and display emissions affect perceived contrast and visibility, guiding realistic measurement setups and informed product specification.

Related standards / context

• IEC TR 62977-2-4 is part of the IEC 62977 series (Electronic displays) and was prepared by IEC TC 110 (Electronic display devices). It is a Technical Report (state-of-the-art overview) and contains no normative references, serving as foundational guidance for developing measurement methods and future standards.

Keywords: IEC TR 62977-2-4, transparent displays, OLED, LCD, liquid crystal, measurement methods, on-screen contrast, through-screen contrast, ambient light, spectral radiance, TDS, augmented reality.

Standards Content (Sample)

IEC TR 62977-2-4 ®
Edition 1.0 2018-11
TECHNICAL
REPORT
colour
inside
Electronic displays –
Part 2-4: Transparent displays – Overview of application scenarios

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IEC TR 62977-2-4 ®
Edition 1.0 2018-11
TECHNICAL
REPORT
colour
inside
Electronic displays –
Part 2-4: Transparent displays – Overview of application scenarios

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 31.120; 31.260 ISBN 978-2-8322-6244-3

– 2 – IEC TR 62977-2-4:2018 © IEC 2018
CONTENTS
FOREWORD . 4
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 Application scenarios . 7
4.1 General . 7
4.2 Performance aspects . 7
4.3 Application cases . 8
4.4 Intended visual information and unwanted contributions from ambient light . 9
4.4.1 General . 9
4.4.2 Visual information on screen . 9
4.4.3 Visual information behind the screen . 10
4.4.4 Intended and disturbing components of light (case 1) . 10
4.4.5 Transmissive transparent display (case 2) . 11
4.4.6 Emissive transparent display (case 3) . 12
5 Component specifications – For measurement . 13
5.1 Spectral radiance . 13
5.2 Object/scene . 14
5.3 Display . 14
5.4 Emissive transparent display. 14
5.5 Transmissive transparent display . 15
5.6 Precautions during the measurements . 15
Bibliography . 19

Figure 1 – Two objects (i.e. a scenery) located behind and seen through a transparent
display . 11
Figure 2 – On-screen contrast generated by electrically controlled transmittance, T
H
and T . 11
L
Figure 3 – Luminance image of a detail of Figure 1 . 12
Figure 4 – Two objects (i.e. a scenery) located behind and seen through a transparent
emissive display (emission shown in green for illustration) . 12
Figure 5 – Example of light which is supposed to be transmitted independently of the
state of the emission, by a transmittance T . 13
e
Figure 6 – Details of Figure 4 . 13
Figure 7 – Emissive and transmissive display screen between the observer and the
object/scene . 14
Figure 8 – Illustration of the effect of diffraction (left) and scattering (right) . 16
Figure 9 – Transparent display's scheme for OLED and LCD without background
ambient illumination . 17
Figure 10 – Transparent display's on-screen performance affected by ambient
illuminance . 17

Table 1 – Application cases . 9
Table 2 – Illustration and explanation of intended and disturbing light components in
the case of transparent display screens (TDS) . 10

– 4 – IEC TR 62977-2-4:2018 © IEC 2018
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRONIC DISPLAYS –
Part 2-4: Transparent displays –
Overview of application scenarios

FOREWORD
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The main task of IEC technical committees is to prepare International Standards. However, a
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data of a different kind from that which is normally published as an International Standard, for
example "state of the art".
IEC TR 62977-2-4, which is a Technical Report, has been prepared by IEC technical
committee 110: Electronic display devices.

The text of this Technical Report is based on the following documents:
Enquiry draft Report on voting
110/972/DTR 110/988A/RVDTR
Full information on the voting for the approval of this technical report 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.
A list of all parts in the IEC 62977 series, published under the general title Electronic displays,
can be found on the IEC website.
Future standards in this series will carry the new general title as cited above. Titles of existing
standards in this series will be updated at the time of the next edition.
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.
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– 6 – IEC TR 62977-2-4:2018 © IEC 2018
ELECTRONIC DISPLAYS –
Part 2-4: Transparent displays –
Overview of application scenarios

1 Scope
This part of IEC 62977, which is a Technical Report, provides a comprehensive overview of
application scenarios for transparent displays of the two major display technologies (liquid
crystal (LC) and organic light emitting diode (OLED) displays) and introduces the observation
and illumination aspects that are taken into account for the establishment of appropriate
measurement methods.
This document only considers direct view displays, it does not include projection displays
(eye-projection and projection to screens.)
2 Normative references
There are no normative references in this document.
3 Terms, definitions and abbreviated terms
For the purposes of this document, the following terms, definitions and abbreviated terms
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 Terms and definitions
3.1.1
AR
augmented reality
overlay of real objects and scenes with artificial visual information
3.1.2
intended visual information
visual information to be presented intentionally
Note 1 to entry: Visual information that is not intended can sometimes be observed, for example reflection of
ambient images.
3.1.3
unwanted contributions from ambient light
visual information that is unintentionally generated (by e.g. reflection of ambient light sources)
and superimposed over the intended visual information, thus creating disturbing visual effects

3.1.4
on-screen contrast
contrast created by the display screen by emission or absorption (transmission), including the
background light transmitted and reflected light, when measured in an ambient lighting
environment
3.1.5
through-screen contrast
contrast of the object or scene behind the transparent display, mainly affected by the
transmissive properties of the transparent display screen, which can also include the
background reflected light and transmitted light outside the regular direction when measured
in an ambient lighting environment
3.2 Abbreviated terms
AR augmented reality
CIE Commission Internationale de l’Eclairage
(International Commission on Illumination)
LC liquid crystal
LCD liquid crystal display
OLED organic light emitting diode
TBLU transparent back-light unit
TDS transparent display screen
VR virtual reality
4 Application scenarios
4.1 General
Transparent displays are considered, for example, for advertising purposes (shop-windows
and showcases, also in combination with touch-screens) and for other similar applications
(e.g. refrigerator doors) where real scenes and objects are overlaid with additional visual
information just as in the case of augmented reality (AR). In airplanes and automobiles head-
up displays are used to present visual information on top of the surrounding scenery. Those
head-up displays, however, use projection optics to display visual information at a certain
distance in front of the observer, so usually no refocusing is required.
Transparent displays may also be realized by a reflective or transmissive screen on which
visual information is being projected, but this case is not considered in this document.
4.2 Performance aspects
Two cases have to be distinguished for the performance of transparent displays:
1) on-screen performance with visual
...