IEC TR 63145-202-40:2026

IEC TR 63145-202-40 ®
Edition 1.0 2026-02
TECHNICAL
REPORT
Eyewear display -
Part 202-40: General information of AR type - Frontal stray lights
ICS 17.180.99; 31.120 ISBN 978-2-8327-1016-6

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CONTENTS
FOREWORD . 2
1 Scope . 4
2 Normative reference . 4
3 Terms, definitions and abbreviations . 4
3.1 Terms and definitions . 4
3.2 Abbreviations . 4
4 Optical see-through (OST) combiner technologies . 5
4.1 General . 5
4.2 Half-tone combiner . 5
4.3 Polarization combiner. 5
4.4 Wavelength-selective combiner . 6
4.5 Spatial half-tone combiner . 6
5 Frontal stray light . 6
5.1 General . 6
5.2 Categorization of frontal stray light . 6
5.2.1 General. 6
5.2.2 Frontal surface reflection . 7
5.2.3 Direct transmission . 7
5.2.4 Facial reflection . 8
5.2.5 Frontal diffraction . 8
5.2.6 Frontal reflection . 8
5.3 Techniques to reduce frontal stray light . 8
5.3.1 Anti-reflection coating . 8
5.3.2 Angle adjustment . 8
5.3.3 Optical filtering . 8
6 Considerations for evaluation methods . 8
6.1 General . 8
6.2 Environment . 9
6.3 2D LMD . 9
6.4 Social acceptance. 9
6.5 Privacy . 10
6.6 Measurement of 2D LMD on 3D surfaces . 11
Bibliography . 12

Figure 1 – Concept of optical see-through combiners . 5
Figure 2 – Schematics of the five types of frontal stray light . 7
Figure 3 – Pictures of the five types of frontal stray light . 7
Figure 4 – MTF curve of the frontal stray light . 10

Table 1 – Luminance of frontal stray light for different viewing angles . 9
Table 2 – Area of frontal stray light for different viewing angles . 10

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Eyewear display -
Part 202-40: General information of AR type - Frontal stray lights

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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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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IEC 63145-202-40 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
110/1793/DTR 110/1822/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/publications.
A list of all parts in the IEC 63145 series, published under the general title Eyewear display,
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.
1 Scope
This document provides general information for frontal stray light from optical see-through
augmented reality (AR) displays and offers guidance on how to evaluate it. It includes overview
of the technology, categorization of the phenomenon, and optical characteristics.
2 Normative reference
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 63145-1-2, Eyewear display - Part 1-2: Generic - Terminology
3 Terms, definitions and abbreviations
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 63145-1-2 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
optical combiner
optical element that enables an optical see-through function in an augmented reality device
3.1.2
frontal stray light
unwanted light emission or reflection from the augmented reality device directed towards the
front of the device and front of user
3.1.3
rear stray light
unwanted light emission or reflection from the augmented reality device directed towards the
user but not into the eye-box
3.2 Abbreviations
AR augmented reality
DOE diffractive optical element
DUT device under test
FOV field of view
HOE holographic optical element
LCD liquid crystal display
LCOS liquid crystal on silicon
LMD light measuring device
OST optical see-through
MTF modulation transfer function
dof depth of focus (LMD)
LMD
4 Optical see-through (OST) combiner technologies
4.1 General
The optical combiner is the key element for OST AR devices. Users can see their environment
when the device is tuned off, and displays the virtual information overlaid on the real world
when the device is tuned on. To enable the optical overlay of virtual images, the optical path
from the virtual image and the real world is combined. As illustrated in Figure 1, there are
several technologies to achieve OST function by exploiting the properties of the light, including
intensity, polarization, wavelength, and imaging through an aperture.

a) Half-tone combiner b) Polarization c) Wavelength- d) Spatial half-tone
combiner selective combiner combiner

NOTE Green and red arrows show the direction of rays and blue arrows show the direction of polarization.
Figure 1 – Concept of optical see-through combiners
4.2 Half-tone combiner
The half-tone combiner uses semi-transparent and semi-reflective characteristics of thin metal
or dielectric coatings. The transmission and the reflection ratio of the incident light can be tur
...