Electronic displays - Part 2-1: Measurements of optical characteristics - Fundamental measurements

IEC 62977-2-1:2021(E) specifies standard measurement conditions and measuring methods for determining the optical characteristics of electronic display modules and systems. These methods apply to emissive and transmissive direct view displays that render real 2D images on a flat panel. This document evaluates the optical characteristics of these displays under darkroom conditions. This document applies to the testing of display performance in response to standard analogue or digital input signals that are not absolute luminance encoded. The input signal is relative RGB without metadata information that codes for real luminance, colour space or colour coordinates. These methods are limited to input signals with typical OETFs such as defined in IEC 61966-2-1, ITU BT. Rec. 601, ITU BT. Rec.709, and ITU BT. Rec.2020. The tests in this document are not approved for use with HDR input signals.
NOTE A flat panel or flat panel display is a display with a flat surface and minimal depth that emits visible light from the surface. The display is subdivided into an array of electronically driven pixels which can be light valves modulating a backlight, or self-luminous. Emissive/transmissive/reflective hybrid displays can be flat panel or flat panel displays.

General Information

Status
Published
Publication Date
04-Jan-2021
Technical Committee
Current Stage
PPUB - Publication issued
Completion Date
05-Jan-2021
Ref Project

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IEC 62977-2-1
Edition 1.0 2021-01
INTERNATIONAL
STANDARD
colour
inside
Electronic displays –
Part 2-1: Measurements of optical characteristics – Fundamental measurements
IEC 62977-2-1:2021-01(en)
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IEC 62977-2-1
Edition 1.0 2021-01
INTERNATIONAL
STANDARD
colour
inside
Electronic displays –
Part 2-1: Measurements of optical characteristics – Fundamental measurements
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 31.120; 31.260 ISBN 978-2-8322-9225-9

Warning! Make sure that you obtained this publication from an authorized distributor.

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– 2 – IEC 62977-2-1:2021 © IEC 2021
CONTENTS

FOREWORD ........................................................................................................................... 6

INTRODUCTION ..................................................................................................................... 8

1 Scope .............................................................................................................................. 9

2 Normative references ...................................................................................................... 9

3 Terms, definitions and abbreviated terms ...................................................................... 10

3.1 Terms and definitions ............................................................................................ 10

3.2 Abbreviated terms ................................................................................................. 11

4 General ......................................................................................................................... 11

4.1 Measured basic quantities .................................................................................... 11

4.2 Electrical driving of the display (depending on the nature of the display) ............... 11

4.3 Data acquisition timing and display driving ............................................................ 12

4.3.1 Stationary measurements .............................................................................. 12

4.3.2 Properties of display under test ..................................................................... 12

5 Standard measuring conditions ...................................................................................... 12

5.1 Standard measuring environmental conditions ...................................................... 12

5.2 Standard measuring darkroom conditions ............................................................. 12

5.3 Standard setup conditions ..................................................................................... 12

5.3.1 General ......................................................................................................... 12

5.3.2 Adjustment of display .................................................................................... 12

5.3.3 Starting conditions of measurements ............................................................. 13

5.3.4 Conditions of measuring equipment ............................................................... 13

5.4 Location of measurement field .............................................................................. 15

5.5 Standard test patterns ........................................................................................... 16

5.6 Viewing direction coordinate system ..................................................................... 16

6 Simple box optical measurement methods ..................................................................... 17

6.1 General ................................................................................................................. 17

6.2 Test patterns......................................................................................................... 17

6.3 Luminance ............................................................................................................ 18

6.3.1 Purpose ......................................................................................................... 18

6.3.2 Measuring conditions ..................................................................................... 18

6.3.3 Measuring method ......................................................................................... 18

6.4 Darkroom contrast ratio ........................................................................................ 19

6.4.1 Purpose ......................................................................................................... 19

6.4.2 Measuring conditions ..................................................................................... 19

6.4.3 Measuring method ......................................................................................... 19

6.5 Luminance uniformity ............................................................................................ 20

6.5.1 Purpose ......................................................................................................... 20

6.5.2 Measuring conditions ..................................................................................... 20

6.5.3 Measuring method ......................................................................................... 20

6.6 Chromaticity .......................................................................................................... 21

6.6.1 Purpose ......................................................................................................... 21

6.6.2 Measuring conditions ..................................................................................... 21

6.6.3 Measuring method ......................................................................................... 22

6.7 White chromaticity and correlated colour temperature ........................................... 22

6.7.1 Purpose ......................................................................................................... 22

6.7.2 Measuring conditions ..................................................................................... 22

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IEC 62977-2-1:2021 © IEC 2021 – 3 –

6.7.3 Measuring method ......................................................................................... 22

6.8 Chromaticity non-uniformity .................................................................................. 23

6.8.1 Purpose ......................................................................................................... 23

6.8.2 Measuring conditions ..................................................................................... 23

6.8.3 Measuring method ......................................................................................... 23

6.9 Chromaticity/colour gamut area............................................................................. 24

6.9.1 Purpose ......................................................................................................... 24

6.9.2 Measuring conditions ..................................................................................... 24

6.9.3 Measuring method ......................................................................................... 25

6.9.4 Chromaticity/colour gamut area in CIE 1931 and CIE 1976 chromaticity

diagram ......................................................................................................... 27

6.10 Luminance and colour variation with viewing direction .......................................... 28

6.10.1 Purpose ......................................................................................................... 28

6.10.2 Measuring conditions ..................................................................................... 28

6.10.3 Measuring method ......................................................................................... 28

7 Display multi-colour optical measuring methods ............................................................ 30

7.1 General ................................................................................................................. 30

7.2 Test patterns......................................................................................................... 30

7.3 Luminance ............................................................................................................ 33

7.3.1 Purpose ......................................................................................................... 33

7.3.2 Measuring conditions ..................................................................................... 33

7.3.3 Measuring method ......................................................................................... 34

7.4 Darkroom contrast ratio ........................................................................................ 35

7.4.1 Purpose ......................................................................................................... 35

7.4.2 Measuring conditions ..................................................................................... 35

7.4.3 Measuring method ......................................................................................... 35

7.5 Luminance uniformity ............................................................................................ 35

7.6 Chromaticity, tristimulus values, and spectra ........................................................ 35

7.6.1 Purpose ......................................................................................................... 35

7.6.2 Measuring conditions ..................................................................................... 36

7.6.3 Measuring method ......................................................................................... 36

7.7 White chromaticity and correlated colour temperature ........................................... 36

7.7.1 Purpose ......................................................................................................... 36

7.7.2 Measuring conditions ..................................................................................... 36

7.7.3 Measuring method ......................................................................................... 36

7.8 Chromaticity/colour gamut area............................................................................. 37

7.8.1 Purpose ......................................................................................................... 37

7.8.2 Measuring conditions ..................................................................................... 37

7.8.3 Measuring method ......................................................................................... 37

7.8.4 Chromaticity/colour gamut area in CIE 1931 and CIE 1976 chromaticity

diagram ......................................................................................................... 37

7.9 Chromaticity non-uniformity .................................................................................. 38

7.10 Luminance and colour variation with viewing direction .......................................... 38

7.10.1 Purpose ......................................................................................................... 38

7.10.2 Measuring conditions ..................................................................................... 38

7.10.3 Measuring method ......................................................................................... 38

8 CIELAB colour gamut volume ........................................................................................ 39

8.1 Purpose ................................................................................................................ 39

8.2 Measuring conditions ............................................................................................ 40

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– 4 – IEC 62977-2-1:2021 © IEC 2021

8.3 Measuring method ................................................................................................ 40

Annex A (normative) RGB boundary colours for CIELAB colour gamut volume

measurements ...................................................................................................................... 43

A.1 General ................................................................................................................. 43

A.2 Equally-spaced 98 boundary colours on the RGB cube ......................................... 43

A.3 Recommended 602 boundary colours on the RGB cube ........................................ 46

Annex B (informative) Calculation method for CIELAB gamut volume................................... 61

B.1 Purpose ................................................................................................................ 61

B.2 Procedure for calculating the colour gamut volume ............................................... 61

B.3 Number of sampled colours .................................................................................. 62

B.4 RGB cube surface subdivision method for CIELAB colour gamut volume

calculation ............................................................................................................ 62

B.4.1 General ......................................................................................................... 62

B.4.2 Assumption .................................................................................................... 62

B.4.3 Uniform RGB grid algorithm ........................................................................... 62

B.4.4 Software example execution .......................................................................... 65

Annex C (informative) Significance of Clause 6 .................................................................... 74

C.1 Summary .............................................................................................................. 74

C.2 Significance of Clause 6 during the research and development stage ................... 74

C.3 Significance of Clause 6 during the manufacturing stage ...................................... 75

C.4 Significance of Clause 6 during the evaluation of other test results ....................... 76

Annex D (informative) Colour-signal luminance .................................................................... 77

Annex E (informative) Gamut rings ...................................................................................... 78

E.1 General ................................................................................................................. 78

E.2 Visualization method ............................................................................................. 79

E.3 Software example ................................................................................................. 80

Bibliography .......................................................................................................................... 82

Figure 1 – Layout diagram of measurement setup with terminology....................................... 14

Figure 2 – Example of measurement locations with nine measurement locations

equally spaced in the display active area .............................................................................. 16

Figure 3 – Representation of the viewing direction, or direction of measurement .................. 17

Figure 4 – Example of centre box test patterns using the standard 4 % and 10 % area

boxes .................................................................................................................................... 18

Figure 5 – Example of uniformity measurement locations with nine measurement

locations ............................................................................................................................... 20

Figure 6 – Examples of a display with colour boundaries represented by the black

triangle in two common chromaticity diagrams ...................................................................... 26

Figure 7 – Top view example of configurations for measuring luminance and colour in

the horizontal viewing direction ............................................................................................. 29

Figure 8 – Side view example of configurations for measuring luminance and colour in

the vertical viewing direction ................................................................................................. 30

Figure 9 – Standard medium APL loading version of the colour tile test pattern with red,

green, blue, and white boxes used for luminance and colour measurements ......................... 31

Figure 10 – Medium APL loading version of colour tile patterns illustrating the

sequence of test patterns used for luminance and colour measurements .............................. 31

Figure 11 – Standard medium APL RGBCMY test pattern used for centre luminance

and colour measurements with 25 % APL ............................................................................. 33

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IEC 62977-2-1:2021 © IEC 2021 – 5 –

Figure 12 – Sequence for measuring luminance at the nine display locations for all

coloured tile patterns ............................................................................................................ 34

Figure 13 – Example of range in colours produced by a given display as represented

by the CIELAB colour space ................................................................................................. 42

Figure B.1 – Analysis flow chart for calculating the CIELAB gamut volume ........................... 61

Figure B.2 – Example of tessellation using a 5 x 5 grid of surface colours on the

RGB cube ............................................................................................................................. 64

Figure B.3 – Example of tessellation for the RGB cube using a 3 x 3 grid ............................. 66

Figure B.4 – Example of tessellation for the CIELAB gamut volume using a 3 x 3 grid .......... 66

Figure C.1 – Example of conceptual scheme for the supply chain of displays and the

usage of the measurement methods (MM) of Clause 0 and Clause 0 .................................... 74

Figure C.2 – Conceptual example of the evaluation of the components ................................. 75

Figure C.3 – Example of a mechanical stress test ................................................................. 76

Figure E.1 – Example of transformation of the CIELAB gamut volume (top) illustrated

by L* slices into the concentric areas of the gamut ring representation (bottom) ................... 79

Figure E.2 – Example of calculation of gamut rings using the data from Table B.1 ................ 80

Table 1 – Summary of display characteristics ......................................................................... 8

Table 2 – Example of luminance of white, red, green, and blue measured at nine

screen locations and the resulting average luminance .......................................................... 21

Table 3 – Example of a white colour measured at nine screen locations and the

resulting chromaticity non-uniformity ..................................................................................... 24

Table 4 – Standard digital-equivalent input signals for rendering the white, primary and

secondary colours in test patterns ......................................................................................... 25

Table 5 – Example of report format for CIELAB gamut volume .............................................. 42

Table A.1 – Equally-spaced 98 RGB boundary colours used for CIELAB colour gamut

volume measurements .......................................................................................................... 44

Table A.2 – Recommended RGB boundary colours used for CIELAB colour gamut

volume measurements .......................................................................................................... 46

Table B.1 – Example data format used for CIELAB colour gamut volume

measurements ...................................................................................................................... 65

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– 6 – IEC 62977-2-1:2021 © IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRONIC DISPLAYS –
Part 2-1: Measurements of optical characteristics –
Fundamental measurements
FOREWORD

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International Standard IEC 62977-2-1 has been prepared by IEC technical committee 110:

Electronic displays.
The text of this International Standard is based on the following documents:
FDIS Report on voting
110/1256/FDIS 110/1275/RVD

Full information on the voting for the approval of this International Standard 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.
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IEC 62977-2-1:2021 © IEC 2021 – 7 –

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.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates

that it contains colours which are considered to be useful for the correct understanding

of its contents. Users should therefore print this document using a colour printer.

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– 8 – IEC 62977-2-1:2021 © IEC 2021
INTRODUCTION

This document describes the common optical measurement methods applicable in the field of

electronic display devices, which can overlap with some of the parts of existing documents

developed within TC 110 (IEC 61747-30-1 [1] , IEC 62341-6-1, IEC 61988-2-1 [2],

IEC 62715-5-1 [3]), that describe the optical measurement methods of the individual

technologies, such as LCD, OLED, PDP and others. This document on common optical

measurement methods is intended to be used as the reference document in future documents

and in revisions of existing documents (e.g. IEC 61747-30-1, IEC 62341-6-1, IEC 61988-2-1,

IEC 62715-5-1). The existing documents will be revised in their maintenance time to refer to

this document to the largest extent possible.

All documents in IEC TC 110 that are concerned with the measurement of optical properties of

electronic displays refer to a set of methods and procedures that are similar to each other, or

sometimes even identical. This document is intended to identify these methods and to describe

them, together with suitable precautions and diagnostics, as a reference for forthcoming

documents to make the work of the involved experts more efficient and to avoid duplication of

efforts.

Introduction of the common optical measurement method (COMM) is also related to a structure

where each kind of optical measurement finds its unambiguous position for identification of

similarities to other methods or for clarification of distinctions. This structural classification

together with a general taxonomy is supposed to make the process of document production

easier, faster and thus more effective.

The above characteristics are summarized in Table 1. The display characteristics that are

addressed in this part of IEC 62977 are indicated by a check mark √ in the table.

Table 1 – Summary of display characteristics
Location D
...

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