ISO/TR 20278:2015

TECHNICAL ISO/TR
REPORT 20278
First edition
2015-12-01
Unwanted reflections from the active
and inactive areas of display surfaces
visible during use
Réflexions non désirées des zones actives et inactives des surfaces de
l’écran visibles durant l’utilisation
Reference number
©
ISO 2015
© ISO 2015, Published in Switzerland
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ii © ISO 2015 – All rights reserved

Contents Page
Foreword .v
1 Scope . 1
2 Terms and definitions . 1
3 Unwanted reflections within the context of the ISO 9241-3xx series .2
3.1 Glare and unwanted reflections . 2
3.2 Direct glare in the context of the ISO 9241-3xx standards series . 2
3.3 Glare by reflection . 3
4 Visual discomfort and glare while using computer displays . 3
4.1 Asthenopia . 3
5 Unwanted reflections from displays . 3
5.1 General . 3
5.2 Glare and unwanted reflections on screens in the ISO 9241-3xx series . 4
6 Pertinent regulations regarding glare and unwanted reflections .4
6.1 European Directive 90-270 — On the minimum safety and health requirements
for work with display screen equipment . 4
6.2 The meaning of disturbing glare within the ISO 9241-3xx series . 4
6.2.1 General. 4
6.2.2 CIE definitions of discomfort glare and disability glare . 4
6.2.3 Unwanted reflections as currently specified and limited in ISO 9241-303,
9241-305 and 9241-307 for the active area of displays (screens) . 5
6.3 Interaction between specular, diffuse and haze reflection components . 6
6.3.1 General. 6
6.3.2 Recognition of the interaction of unwanted reflection components in the
ISO 9241-3xx series . 6
7 Luminance balance . 6
8 Glare and the ambient illumination in the office-working environment .6
8.1 Ambient illuminance . 6
8.2 Arrangement of the computer work area . 7
8.3 Surface finishes (reflectivity) . 7
8.3.1 General. 7
8.3.2 Conversion of specular gloss values to specular reflectance values . 8
9 Literature review of research regarding unwanted reflections from the bezel,
screen housing, or other inactive areas of the display visible during use .8
9.1 General . 8
9.2 Bezel gloss . 8
9.2.1 Howarth and Hodder, 2004 . 8
9.2.2 Béland and Andrén . 8
9.2.3 Howarth and Hodder, 2013 . 8
9.3 Bezel reflectance . 9
9.3.1 General. 9
9.3.2 Hunter, et al. . 9
9.3.3 Soderston, et al. . 9
9.3.4 Béland and Andrén .10
9.3.5 Howarth and Hodder .11
9.3.6 Conclusions from the literature regarding bezel gloss and reflectance .11
10 A review of the literature regarding eyestrain due to vergence and accommodative
demands of glare reflections .11
10.1 Accommodative stress .11
10.2 Vergence stress .12
11 Summary and conclusions .12
Bibliography .14
iv © ISO 2015 – All rights reserved

Foreword
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The committee responsible for this document is ISO/TC 159, Ergonomics, Subcommittee SC 4, Ergonomics
of human-system interaction.
TECHNICAL REPORT ISO/TR 20278:2015(E)
Unwanted reflections from the active and inactive areas of
display surfaces visible during use
1 Scope
This Technical Report provides users a summary of the existing knowledge about ergonomics
requirements for unwanted reflections on electronic displays. The document furthermore provides
some guidance on specification of unwanted reflections.
NOTE ISO 9241 contains normative requirements related to unwanted reflections. It is possible that the
information contained in this Technical Report will be used for a future update of ISO 9241.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1
asthenopia
weakness or tiring of the eyes accompanied by pain, headache, and dim vision
Note 1 to entry: Symptoms include pain in or around the eyes; headache, usually aggravated by using the eyes for
close work; fatigue; vertigo; and reflex symptoms such as nausea, twitching of facial muscles, or migraine.
[SOURCE: Taber’s Medical Dictionary]
2.2
disability glare
glare that impairs the vision of objects without necessarily causing discomfort
2.3
direct glare
glare caused by self-luminous objects located in the visual field, especially near the line of sight
2.4
discomfort glare
glare that causes discomfort without necessarily impairing the vision of objects
2.5
glare
condition of vision in which there is discomfort or a reduction in the ability to see details or objects,
caused by an unsuitable distribution or range of luminance, or by extreme contrasts
2.6
glare by reflection
glare produced by reflections, particularly when the reflected images appear in the same or nearly the
same direction as the object viewed
2.7
gloss (of a surface)
mode of appearance by which reflected highlights of light sources of objects are perceived as
superimposed on the surface due to the directionally selective properties of that surface
2.8
glossmeter
instrument for measuring the various photometric properties of a surface giving rise to gloss
2.9
reflectometer
instrument for measuring quantities pertaining to reflection
2.10
specular gloss
ratio of the luminous flux reflected from an object in the specular direction for a specified source
and receptor angle to the luminous flux reflected from glass with a refractive index of 1,567 in the
specular direction
2.11
veiling glare (imaging)
light, reflected from an imaging medium, that has not been modulated by the means used to
produce the image
3 Unwanted reflections within the context of the ISO 9241-3xx series
3.1 Glare and unwanted reflections
At various places in the ISO 9241-3xx series, we specifically adopt the CIE definition of glare, which
includes both discomfort glare and disability glare. We note that the CIE defines discomfort glare
verbally as:
[11]
“glare which causes discomfort without necessarily impairing the vision of objects”,
and disability glare as
[13]
“glare t
...