IEC 62977-2-2:2020

IEC 62977-2-2 ®
Edition 1.0 2020-09
INTERNATIONAL
STANDARD
colour
inside
Electronic displays –
Part 2-2: Measurements of optical characteristics – Ambient performance
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IEC 62977-2-2 ®
Edition 1.0 2020-09
INTERNATIONAL
STANDARD
colour
inside
Electronic displays –
Part 2-2: Measurements of optical characteristics – Ambient performance

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 31.120; 31.260 ISBN 978-2-8322-8816-0

– 2 – IEC 62977-2-2:2020 © IEC 2020
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 9
2 Normative references . 9
3 Terms, definitions, abbreviated terms and symbols . 9
3.1 Terms and definitions . 9
3.2 Abbreviated terms . 10
3.3 Symbols . 10
4 Standard measuring conditions . 11
4.1 Standard measuring environmental conditions . 11
4.2 Viewing direction and light source coordinate system . 12
4.3 Standard lighting conditions . 12
4.3.1 General . 12
4.3.2 Standard measuring darkroom conditions . 13
4.3.3 Standard ambient illumination . 13
4.3.4 Standard illumination geometries . 14
4.4 Standard setup conditions . 20
4.4.1 General . 20
4.4.2 Adjustment of display . 20
4.4.3 Starting conditions of measurements . 21
4.4.4 General conditions of measuring equipment . 21
4.5 Reflection standards . 22
4.5.1 General . 22
4.5.2 Diffuse reflectance standard . 22
4.6 Locations of measurement field. 23
5 Darkroom luminance and spectra. 23
5.1 General . 23
5.2 Test pattern . 23
5.2.1 General . 23
5.2.2 Simple box test patterns . 23
5.2.3 Multi-colour test pattern . 24
5.2.4 Measuring conditions . 25
5.2.5 Measuring method . 25
6 Reflection measurements . 26
6.1 General . 26
6.2 Measuring conditions . 26
6.3 Measuring the hemispherical diffuse reflectance . 27
6.4 Measuring the reflectance factor for a directed light source. 28
7 Ambient optical performance . 30
7.1 General . 30
7.2 Ambient contrast ratio . 30
7.2.1 General . 30
7.2.2 Measuring conditions . 30
7.2.3 Measuring method . 30
7.3 Ambient display colour . 31

7.3.1 General . 31
7.3.2 Measuring conditions . 31
7.3.3 Measuring method . 31
7.4 Ambient colour gamut volume . 33
7.4.1 General . 33
7.4.2 Measuring conditions . 34
7.4.3 Measuring method . 34
Annex A (normative) RGB boundary colours for CIELAB gamut volume measurements . 37
A.1 General . 37
A.2 Equally-spaced 98 boundary colours on the RGB cube . 37
A.3 Recommended 602 boundary colours on the RGB cube . 40
Annex B (informative) Calculation method for CIELAB gamut volume. 54
B.1 Purpose . 54
B.2 Procedure for calculating the colour gamut volume . 54
B.3 Number of sampled colours . 55
B.4 RGB cube surface subdivision method for CIELAB gamut volume calculation . 55
B.4.1 General . 55
B.4.2 Assumption . 55
B.4.3 Uniform RGB grid algorithm . 55
B.4.4 Software example execution . 57
Bibliography . 67

Figure 1 – Representation of the viewing direction (direction of measurement) and
coordinate system used for light source configuration . 12
Figure 2 – Illustrated examples for directional illumination . 15
Figure 3 – Example of the measuring setup using directional illumination where
θ = 40° and θ = 30° . 16
S R
Figure 4 – Example of ring light illumination measuring setup where θ ± ∆ = 35 ± 5
S
and θ = 20° . 17
R
Figure 5 – Detailed schematic of ring light characteristics . 18
Figure 6 – Example of measurement geometries for hemispherical illumination using
an integrating sphere (left) or sampling sphere (right) . 19
Figure 7 – Layout diagram of measurement setup . 22
Figure 8 – Example of centre box test patterns using the standard 4 % and
10 % area boxes . 24
Figure 9 – Standard medium APL RGBCMYWx test pattern used for centre luminance
and spectra measurements with 25 % APL . 25
Figure 10 – Example of the range in colours produced by a display . 36
Figure B.1 – Analysis flow chart for calculating the CIELAB gamut volume . 54
Figure B.2 – Example of tessellation using 5 × 5 grid of surface colours on the
RGB cube . 57
Figure B.3 – Example of tessellation for the RGB cube using a 3 × 3 grid . 59
Figure B.4 – Example of tessellation for the CIELAB gamut volume using a 3 × 3 grid . 59

Table 1 – Measurement structure from optical quantities to evaluation and to results
(top down) . 8
Table 2 – Summary of symbols . 11
Table 3 – Eigenvalues M and M for CIE daylight Illuminants D50, D65, and D75 . 28
1 2
– 4 – IEC 62977-2-2:2020 © IEC 2020
Table A.1 – Equally-spaced 98 RGB boundary colours used for CIELAB gamut volume
measurements . 38
Table A.2 – Recommended RGB boundary colours used for CIELAB colour gamut

volume measurements . 41
Table B.1 – Example RGB boundary colours used to demonstrate how the CIELAB
colour gamut volume can be calculated . 58

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRONIC DISPLAYS –
Part 2-2: Measurements of optical characteristics
...