IEC TR 63145-202-40:2026

Eyewear display - Part 202-40: General information of AR type - Frontal stray lights

IEC TR 63145-202-40:2026 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.

General Information

• Status: Published
• Publication Date: 11-Feb-2026
• ICS: 17.180.99 - Other standards related to optics and optical measurements
• ICS: 31.120 - Electronic display devices
• Technical Committee: TC 110 - Electronic displays
• Drafting Committee: WG 12 - TC 110/WG 12
• Current Stage: PPUB - Publication issued
• Start Date: 12-Feb-2026
• Completion Date: 20-Feb-2026

Overview

IEC TR 63145-202-40:2026 is a technical report published by the International Electrotechnical Commission (IEC) that provides essential information and guidance on frontal stray light in optical see-through (OST) augmented reality (AR) eyewear displays. The standard outlines the technology framework, defines the phenomenon of frontal stray light, categorizes its various types, and discusses optical characteristics relevant to AR device design and evaluation. This report addresses important aspects such as social acceptance and privacy concerns arising from unintended light emissions, helping manufacturers, designers, and evaluators optimize user experience and safety.

Keywords: eyewear display, augmented reality, AR, optical see-through, frontal stray light, IEC standard, OST, stray light evaluation.

Key Topics

Optical See-Through Combiner Technologies

• Half-tone combiners: Utilize semi-transparent coatings to balance reflection and transmission, commonly used in bug-eye and birdbath optics.
• Polarization combiners: Rely on orthogonal polarization to combine real-world and virtual images with minimal luminance loss, ideal for polarized display engines like LCD and LCOS.
• Wavelength-selective combiners: Use diffractive or holographic elements (DOE/HOE) to reflect specific light wavelengths, enabling selective virtual image display.
• Spatial half-tone combiners: Employ spatially separated mirrors to simultaneously render both real and virtual scenes, adjusting brightness ratio by their proportion.

Frontal Stray Light Phenomenon

The document categorizes frontal stray light in AR eyewear into five types:

• Frontal surface reflection: Reflection of ambient light at the device’s outer surface, observed regardless of device activity.
• Direct transmission: Virtual image leak from the display engine, visible externally when the device is on.
• Facial reflection: Reflection of virtual images off the user’s face or eyes.
• Frontal diffraction: Unintended light directed outwards due to symmetrical diffraction in DOE/HOE-based optics.
• Frontal reflection: Mirror-like reflection of virtual images away from the user’s eye-box, typical in birdbath optics.

Methods to Reduce Frontal Stray Light

• Anti-reflection coatings: Minimize surface reflections on both optical and mechanical parts.
• Angle adjustment: Redirect stray light by tilting or wrapping the optics, though this does not reduce the light itself.
• Optical filtering: Use polarization or spectral filters to block unwanted light while maintaining transparency.

Evaluation Considerations

• Recommendations for environmental conditions (e.g., dark room measurements) to ensure consistent evaluation.
• Utilization of light measuring devices (LMD) placed at standardized distances and angles to assess luminance and area of stray light.
• Social acceptance metrics-such as maximum stray light luminance and size-as well as privacy assessment via modulation transfer function (MTF) analysis.

Applications

IEC TR 63145-202-40:2026 is valuable for a range of applications:

• AR device design and manufacturing: Guides designers in minimizing visible stray light, improving user comfort, privacy, and social acceptance.
• Product testing and evaluation: Provides methodologies for reliably measuring and comparing frontal stray light between AR devices.
• Compliance and quality assurance: Supports industry professionals in meeting current international standards and expectations for augmented reality eyewear.
• Privacy-sensitive environments: Offers guidelines to assess and mitigate privacy risks posed by visible virtual images projected towards onlookers or bystanders.

Related Standards

For a holistic approach to eyewear display evaluation, the following IEC standards offer complementary guidance:

• IEC 63145-1-2 - Eyewear display - Part 1-2: Generic - Terminology
• IEC 62977-2-1 - Electronic displays - Part 2-1: Fundamental measurements of optical characteristics
• IEC TR 62977-2-5 - Electronic display devices - Transparent displays optical measurements
• IEC 62715-5-1 - Flexible display devices - Measuring methods of optical performance

By following IEC TR 63145-202-40:2026, stakeholders can effectively evaluate and mitigate frontal stray light in AR eyewear, enhancing both user safety and industry-wide confidence in augmented reality technologies.

Standards Content (Sample)

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
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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
...