IEC 63145-20-10:2019

IEC 63145-20-10 ®
Edition 1.0 2019-08
INTERNATIONAL
STANDARD
colour
inside
Eyewear display –
Part 20-10: Fundamental measurement methods – Optical properties
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IEC 63145-20-10 ®
Edition 1.0 2019-08
INTERNATIONAL
STANDARD
colour
inside
Eyewear display –
Part 20-10: Fundamental measurement methods – Optical properties

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 17.180.99; 31.120 ISBN 978-2-8322-7269-5

– 2 – IEC 63145-20-10:2019  IEC 2019
CONTENTS
FOREWORD . 4
1 Scope . 6
2 Normative references . 6
3 Terms, definitions, abbreviated terms and letter symbols . 6
3.1 Terms and definitions. 6
3.2 Abbreviated terms . 7
3.3 Letter symbols (symbols for quantities and units) . 7
4 Standard measurement conditions . 8
4.1 Standard environmental conditions . 8
4.2 Power supply . 8
4.3 Warm-up time . 8
4.4 Dark room condition . 9
5 Measurement systems . 9
5.1 Standard coordinate system . 9
5.2 Measurement equipment . 10
5.2.1 Light measuring device (LMD) . 10
5.2.2 Stage conditions . 11
5.2.3 Setup conditions . 12
5.3 Test patterns . 14
5.3.1 General . 14
5.3.2 Checkerboard pattern . 14
5.3.3 Solid colour patterns . 14
5.4 Measuring points . 14
6 Measurement methods for optical characteristics . 15
6.1 General . 15
6.2 Preparation . 15
6.3 Luminance and luminance uniformity (non-uniformity) . 16
6.3.1 General . 16
6.3.2 Measurement procedure . 16
6.3.3 Calculation . 16
6.3.4 Report . 17
6.4 Chromaticity and colour gamut . 17
6.4.1 General . 17
6.4.2 Measurement procedure . 17
6.4.3 Calculation . 17
6.4.4 Report . 18
6.5 Chromaticity uniformity . 18
6.5.1 General . 18
6.5.2 Measurement procedure . 18
6.5.3 Calculation . 18
6.5.4 Report . 18
6.6 Contrast ratio . 19
6.6.1 General . 19
6.6.2 Measurement procedure . 19
6.6.3 Calculation . 19
6.6.4 Report . 19

6.7 Field of view (FOV) . 20
6.7.1 General . 20
6.7.2 Measurement procedure . 20
6.7.3 Calculation . 21
6.7.4 Report . 22
6.8 Eye-box based on luminance . 23
6.8.1 General . 23
6.8.2 Measurement procedure . 23
6.8.3 Report . 24
6.9 Pixel angular density . 24
6.9.1 General . 24
6.9.2 Measurement procedure . 24
6.9.3 Report . 25
Annex A (informative) Estimating the eye point . 26
A.1 General . 26
A.2 Eye point based on full field luminance method . 26
A.2.1 General . 26
A.2.2 Measurement procedure . 26
A.3 Eye point based on Michelson contrast method . 27
A.3.1 General . 27
A.3.2 Measurement procedure . 27
Annex B (informative) Explanation of measurement results . 29
B.1 Geographic coordinate chart . 29
B.2 Visual field . 29
Bibliography . 31

Figure 1 – Spherical coordinate system . 9
Figure 2 – Three-dimensional Cartesian coordinate system . 10
Figure 3 – Example of LMD structure . 11
Figure 4 – Examples of measurement setup . 13
Figure 5 – Example of 5 x 5 checkerboard pattern . 14
Figure 6 – Measuring points for the centre and multi-point measurement . 15
Figure 7 – Example of FOV boundary . 21
Figure 8 – Example of pixel angular density measurement . 24
Figure A.1 – Example of luminance image . 27
Figure A.2 – Example of image of resolution test pattern . 28
Figure B.1 – Example of geographic coordinate chart . 29
Figure B.2 – Example of visual field . 30

Table 1 – Letter symbols (symbols for quantities and units) . 8

– 4 – IEC 63145-20-10:2019  IEC 2019
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
EYEWEAR DISPLAY –
Part 20-10: Fundamental measurement methods – Optical properties

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
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2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 63145-20-10 has been prepared by IEC technical committee TC
110: Electronic displays.
The text of this International Standard is based on the following documents:
FDIS Report on voting
110/1105/FDIS 110/1131/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 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 "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.
A bilingual version of this publication may be issued at a later date.

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.
– 6 – IEC 63145-20-10:2019  IEC 2019
EYEWEAR DISPLAY –
Part 20-10: Fundamental measurement methods – Optical properties

1 Scope
This part of IEC 63145 specifies the standard measurement conditions and measurement
methods for determining the optical properties of eyewear displays. This document applies to
non-see-through type (virtual reality “VR” goggles) and see-through type (augmented reality
“AR” glasses) eyewear displays using virtual image optics.
Contact lens-type displays and retina direct projection displays are out of the scope of this
document.
2 Normative references
There are no normative references in this document.
3 Terms, definitions, abbreviated terms and letter symbols
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1.1
entrance pupil of the LMD
optical image of the physical aperture stop, as ‘seen’ through the front of the LMD lens
system
Note 1 to entry: If there is no lens in front of the aperture, the entrance pupil’s location and size are identical to
that of the aperture stop.
3.1.2
eye-box
qualified viewing space
three-dimensional space within which users place their eye so as to be able to properly see
the entire virtual image without moving the head or making any other adjustment (other than
the natural rotation of the eye)
Note 1 to entry: “Able to properly see” means that the display image fulfils all the requirements indicated in the
product specification.
3.1.3
eye point
design location at which the entrance pupil of the eye is placed to achieve the optimal
performance when using an eyewear display and which serves as the origin location of the
measurement
Note 1 to entry: An estimating example is shown in Annex A.
3.1.4
eye relief
distance from the cornea of the eye to the closest optical element of the virtual-image display
3.1.5
field of view
angular region subtending the proper active area of the virtual image as observed from the
eye point of the eyewear display
Note 1 to entry: “Proper” means that the display image fulfils all the requirements indicated in the product
specification, for example the limits of luminance, resolution, etc.
3.1.6
measurement direction
direction from which the eye point views the virtual image, as measured relative to the optical
axis of the eyewear display using spherical coordinates
Note 1 to entry: See Figure 1.
3.1.7
pixel angular density
pixel number per unit degree
3.2 Abbreviated terms
AR augmented reality
CCD charge-coupled device detector
DUT device under test
FOV field of view
LMD light measuring device
VR virtual reality
3.3 Letter symbols (symbols for quantities and units)
The letter symbols for eyewear displays are shown in Table 1.

– 8 – IEC 63145-20-10:2019  IEC 2019
Table 1 – Letter symbols (symbols for quantities and units)
Quantities Symbol Unit
P
Measuring point (i = 0: centre)
i
Arbitrary luminance of a position (x, y, z) and direction
(x, y; z, α, Ψ)
L
cd/m
v
(α, Ψ) on the eyewear display
L
Maximum luminance
cd/m
vM
L
Minimum luminance cd/m
vm
L
Average luminance (spatial) cd/m
va
L
Centre luminance
cd/m
vC
Luminance uniformity U %
Luminance non-uniformity NU %
A
Angle of horizontal FOV degree
h
A
Angle of vertical FOV degree
v
A
Angle of diagonal FOV degree
d
W
Width of eye-box mm
box
H
Height of eye-box mm
box
CIE 1976 chromaticity coordinates at P u’ , v’

i i i
Chromaticity difference in CIE 1976 uniform-
∆u’v’
chromaticity-scale diagram
Contrast ratio CR
D
Pixel angular density pixel per degree (ppd)
L
Solid angle of measurement field Ω sr

4 Standard measurement conditions
4.1 Standard environmental conditions
Unless otherwise specified, all tests and measurements for eyewear displays shall be carried
out after sufficient warm-up time for the illumination sources and DUT (see 4.3), under the
following standard environmental conditions:
– temperature 22 °C to 28 °C,
– relative humidity 25 % to 85 %, and
– atmospheric pressure 86 kPa to 106 kPa.
When different environmental conditions are used, they shall be reported in detail in the
specification.
4.2 Power supply
In order to stabilize the performances of the DUT, the power supply for driving the DUT shall
be adjusted according to the specification of the DUT.
NOTE When the DUT is driven by a battery, it is less susceptible to power supply fluctuations.
4.3 Warm-up time
The optical performances of DUT are affected by the transient temperature behavior of the
device. It takes a certain time for the luminance output of the DUT to achieve a steady state.

If the luminance output is not within a ±3 % variation, it shall be reported. All measuring
conditions shall be kept constant during the measurements.
NOTE If the measurement result does not become a steady state, it might be influenced by the output fluctuation
of the DUT and/or the fluctuation of the LMD such as noise.
4.4 Dark room condition
The luminance contribution from the background in the test room reflected off the
measurement space shall be less than 1/20 of the minimum luminance output from the DUT. If
the condition is not satisfied, then background subtraction is required and it shall be noted in
the report.
5 Measurement systems
5.1 Standard coordinate system
To indicate the spatial positions of virtual images, a spherical coordinate system of elevation
(latitude) and azimuth (longitude) shall be used in the measurements; the polar axis is
vertically oriented as shown in Figure 1. The angles measured in the vertical half plane of the
data are elevation angles, denoted as α, and the horizontal angles to the half plane are
azimuth angles, denoted as Ψ. The origin direction (α = 0, Ψ = 0) of the spherical coordinate
system shall be coincident with the optical axis of the DUT.
NOTE 1 The spatial positions of the virtual image can be expressed in a geographic coordinate chart, as shown in
Annex B.
A three-dimensional Cartesian coordinate system (x, y, z) is used to indicate the positional
relationship among the eye-box, eye point, eye relief of the DUT, entrance pupil of the LMD
and so on, as shown in Figure 2. Unless specified otherwise, the eye point of the DUT is
placed at the centre of the entrance pupil of the eye, and defined as the origin of the
coordinate system. The manufacturer or supplier of the DUT shall specify the eye point
position or the eye relief.
The origins of both the spherical coordinate system and the Cartesian coordinate system shall
be located at the eye point.
NOTE 2 In the case of a binocular eyewear display, the left ocular can be used as the origin of the Cartesian
coordinate system.
Figure 1 – Spherical coordinate system

– 10 – IEC 63145-20-10:2019  IEC 2019

NOTE This figure is an example of the entrance pupil of the eye located at the eye point of the DUT.
Figure 2 – Three-dimensional Cartesian coordinate system
5.2 Measurement equipment
5.2.1 Light measuring device (LMD)
5.2.1.1 General
The configurations and operating conditions of the equipment should comply with the
structures specified in each item. To ensure accurate measurements, the following
requirements shall be applied. Otherwise, the differences shall be noted in the report.
ISO/CIE 19476 [8] describes the LMD evaluation procedures.
The optics of the LMD (a spot LMD or a 2D imaging LMD) shall be equivalent to the human
eye, as shown in Figure 3. The LMD shall be equipped with a finder. The position of the
entrance pupil (aperture) of the LMD shall be provided by the manufacturer or the supplier.
The size of the entrance pupil of the LMD should be set between 2 mm and 5 mm, and shall
be smaller than the output light field of the DUT. The LMD to measure the optical
characteristics such as luminance and colour shall be calibrated with the appropriate
photometric or spectrometric standards. The LMD should be carefully checked before
measurements, considering the following points:
– sensitivity of the measured quantity to measuring light;
– errors caused by the veiling glare and lens flare (i.e., stray light in the optical system);
– timing of data-acquisition, low-pass filtering and aliasing-effects;
– linearity of detection and data conversion;
– measurement field size.
NOTE See IEC TR 63145-1-1:2018 [1], 6.2.
_____________
Numbers in square brackets refer to the Bibliography.

Figure 3 – Example of LMD structure
5.2.1.2 Spectrometer-type LMD
When a spectrometer-type LMD such as a spectroradiometer is used, the wavelength range
shall be at least 380 nm to 780 nm, the spectral bandwidth shall be 5 nm or smaller, and the
wavelength accuracy shall be 0,3 nm or smaller.
5.2.1.3 Filter-type LMD for measuring luminance
When a filter-type LMD such as a luminance meter is used to ensure the luminance accuracy
for the intended DUT light sources, its spectral responsivity should comply with the spectral
luminous efficiency for CIE photopic vision or it should be compared with a calibrated
spectrometer. The spectral mismatch correction factor can be applied, if necessary.
NOTE CIE-f ’ indicates the spectral mismatch factor between the spectral responsivity of the filter-type LMD and
the CIE photopic luminous efficiency function. Details of the spectral mismatch correction factor are given in
ISO/CIE 19476 [8].
5.2.1.4 Filter-type LMD for measuring colour
When a filter-type LMD such as a colorimeter is used to ensure the colour accuracy for the
intended DUT light sources, its spectral responsivity should comply with the CIE colour-
matching functions for the CIE 1931 standard colorimetric observer (see ISO 11664-1 [7]) or it
should be compared with a calibrated spectrometer. The colour correction factors can be
applied, if necessary. The filter-type LMD shall not be used for absolute colour quantities, but
for relative colour quantities such as colour uniformity.
5.2.1.5 2D imaging LMD
The 2D imaging LMD (using a two-dimensional sensor such as a CCD) is a kind of a filter-
type LMD. The performances of the 2D imaging LMD shall comply with 5.2.1.3 and 5.2.1.4.
The valid measurement field angle of the 2D imaging LMD shall be confirmed and the
peripheral image of the 2D imaging LMD shall confirm the absence of vignetting. The number
of pixels of the 2D imaging LMD should not be less than four times the virtual image sub-
pixels number within the measurement field.
NOTE 1 The measurement field of some 2D imaging LMDs is affected by the smaller entrance aperture.
NOTE 2 The 2D imaging LMD using a colour filter array might cause moiré.
5.2.2 Stage conditions
5.2.2.1 General
The stage shall be used to realize the coordinate system specified in 5.1. The stage should be
constructed with the equivalent of a biaxial goniometer and an orthogonal three-axis
translation stage.
– 12 – IEC 63145-20-10:2019  IEC 2019
5.2.2.2 Goniometer
A biaxial goniometer shall be assembled to be capable of measuring the azimuth (horizontal)
and elevation (vertical) angles in the spherical coordinate system as shown in Figure 1.
Examples of a five-axis stage are shown in Figure 4. The angular accuracy should be 0,1° or
less. The goniometer can be pivoted at the centre of the entrance pupil of the LMD or 10 mm
behind the entrance pupil.
5.2.2.3 Translation stage
An orthogonal three-axis translation stage is assembled with an adequate range to cover the
measuring distance such as the eye-box volume, and, if necessary, to cover the interpupillary
distance for binocular DUTs, as in the examples shown in Figure 4. The translation accuracy
should be 0,05 mm or less.
5.2.3 Setup conditions
The DUT shall be mounted on a stable platform to ensure image stability. The LMD position
relative to the DUT shall be moved, and it can use a five-axis system (a biaxial goniometer
and orthogonal three-axis translation stage). Examples of a measuring setup are shown in
Figure 4. The eye point of the DUT shall match the origin of the biaxial goniometer. The
optical axis of the DUT which is decided by the manufacturer or supplier shall be adjusted to
the optical axis of the LMD and shall be aligned with the z-axis of the orthogonal three-axis
translation stage. The aspect of the virtual image of DUT shall be adjusted to the x- and y-
axes of the orthogonal three-axis translation stage.
To measure the condition from an anterior view, when the DUT does not suppose a change of
gaze angle (eye rotation), the origin of a biaxial goniometer shall be assumed as the entrance
pupil of the eye (i.e. eye point of the DUT), not the rotation centre of the eyeball (eye
movement). When the origin of the biaxial goniometer does not match the eye point of the
DUT, the coordinate correction shall be required and shall be reported. When the DUT
supposes a change of the gaze angle, the detailed information such as the position of the
rotation centre shall be specified by the manufacturer or the supplier and shall be reported.
NOTE 1 The cornea position is about 3 mm in front of the iris position. Some optical designs are used based on
the cornea position.
NOTE 2 The rotation centre of the eyeball is located about 10 mm behind the iris (entrance pupil of the eye).

a) LMD mounted on a biaxial goniometer and an orthogonal three-axis translation stage

b) DUT mounted on a biaxial goniometer and an orthogonal three-axis translation stage
NOTE 1 When the LMD is installed on the biaxial goniometer, the elevation stage is set on the azimuth stage.
NOTE 2 Some eyewear displays change their virtual image depending on their orientation.
Figure 4 – Examples of measurement setup

– 14 – IEC 63145-20-10:2019  IEC 2019
5.3 Test patterns
5.3.1 General
The following test patterns shall be specified by the manufacturer or the supplier, and the
applied test pattern shall be noted in the report. When other test patterns are applied, they
shall be noted in the report.
NOTE Unlike a conventional display, the boundary of the display area is not clear, and the choice of test pattern
might affect the measurement results.
5.3.2 Checkerboard pattern
The checkerboard pattern as shown in Figure 5 should be used to measure the applicable
properties and can be used for alignment of the DUT and LMD optics. The checkerboard
pattern with crosses, whose example is specified in ISO 9241-305 [6], should also be used for
alignment of the DUT and LMD optics. Both patterns of white and black at the centre can be
used. Usually, a white and black checkerboard pattern is used, but a checkerboard pattern of
another colour (red, green, blue and so on) and black can be used if necessary.

NOTE The 5 x 5 checkerboard pattern is helpful in navigating across the virtual image and focusing the LMD.
Figure 5 – Example of 5 x 5 checkerboard pattern
5.3.3 Solid colour patterns
The solid colour patterns can be used to measure the optical qualities. The colours should be
defined in terms of the display primaries as white, black, red, green and blue. The pattern (full
screen) is filled with a single colour.
5.4 Measuring points
The centre point (one point) or the multi-point (five points or nine points) measurements shall
be applied, which are provided by the manufacturer or supplier. The measuring point(s) of
one-point, five-point, and nine-point measurements are P , P to P , and P to P ,
0 0 4 0 8
respectively, as shown in Figure 6. When using other measuring points the manufacturer or
the supplier should point out these positions. The applied measuring points are defined in
each measuring item. If other measuring points are applied, this shall be defined in the
relevant specification.
NOTE The centre point measurement is carried out to measure the typical characteristics of the DUT. The five-
point and nine-point measurements are carried out to measure the deviations, averages, and uniformities.

Figure 6 – Measuring points for the centre and multi-point measurement
6 Measurement methods for optical characteristics
6.1 General
In order to evaluate the optical characteristics of an eyewear display, the luminance, colour
(chromaticity coordinates), contrast ratio, FOV, eye-box and pixel angular density shall be
measured. The FOV and eye box are calculated based on the luminance and contrast ratio.
6.2 Preparation
The eyewear display to be measured (DUT) should be placed in the measurement
arrangement specified in 5.2.3 using the chekerboard pattern specified in 5.3.2. The entrance
pupil of the LMD and the eye point of the DUT shall match the origin position of the five-axis
system (x = 0, y = 0, z = 0, α = 0, Ψ = 0).
NOTE In case the pivoting point of the LMD is 10 mm behind the entrance pupil, this pivoting point can be used,
instead of the entrance pupil, to match the origin position of the measurement.
The DUT-adjustable conditions which are related to the optical properties shall be specified
by the manufacturer or supplier and reported. Some DUTs use image processing, and if a
setting for the image processing is also adjustable, the default setting specified by the
manufacturer or the supplier shall be applied and reported.
The focus of the LMD shall be adjusted through the image finder to become the clear virtual
image. A raster pattern with a high resolution (the highest resolution is one-by-one line pair)
which is appropriate for the DUT and provided by the manufacturer or the supplier, can be
applied for adjustment of the virtual image focus.
The optical measurement capabilities of the LMD, such as luminance and spectral radiance,
should be traceable to national metrology standards under the same conditions (for example
entrance pupil size, measurement field angle and focus distance in some structures).

– 16 – IEC 63145-20-10:2019  IEC 2019
The optical quantities at different measuring points (directions) should be measured at the
steady state after the required time specified in 4.3.
NOTE Some eyewear displays have eye-tracking capabilities for optimizing the image. The gaze direction of the
LMD might not agree with the gaze direction as detected by the DUT for a true eye.
6.3 Luminance and luminance uniformity (non-uniformity)
6.3.1 General
The purpose of this method is to measure the luminance and luminance uniformity of the DUT,
by positioning the entrance pupil of the LMD at the eye point. The LMD will pivot at the
entrance pupil to point to the desired virtual image measurement position.
NOTE 1 In case the pivoting point of the LMD is 10 mm behind the entrance pupil, this pivoting point can be used,
instead of the entrance pupil, to match the eye point of the DUT.
The standard measurement conditions (Clause 4), standard coordinate system (5.1),
measurement equipment (5.2) and checkerboard pattern (5.3.2) shall be applied.
NOTE 2 For wide-field-of-view DUTs, the checkerboard pattern might not be accurate enough. In that case, the
manufacturer or supplier will specify the pattern.
6.3.2 Measurement procedure
The luminance values, L (0, 0, 0, α, Ψ), of the nine points on the virtual image are measured

v
using the as following procedure:
a) Position the DUT.
b) Display the checkerboard pattern with the white centre.
c) Adjust the LMD to match the entrance pupil at the eye point of the DUT and focus at a
specified virtual image distance.
d) Adjust the measurement direction of the LMD to align to position P (i = 0 to 8).
i
e) Measure the luminance L (0, 0, 0, α , Ψ ) of the DUT at position P .
vi i i i
f) Repeat for the other ocular, if applicable.
6.3.3 Calculation
Luminance non-uniformity, NU, is calculated by using the following formula:
LL−
vM va
NU= x 100 % (1)
L
va
where
L is the maximum luminance value of the measurement points;
vM
L is the average luminance value, which is calculated by the following formula:
va
LL= (2)
va ∑ vi
i=0
where
L is the luminance value of the measurement at position P .

vi i
For some applications, luminance uniformity, U, is applied and is calculated by the following
formula:
U 100− NU % (3)
6.3.4 Report
The following items should be reported:
– luminance L (0, 0, 0, α , Ψ ) of each position P , with the elevation angle α and the
vi i i i i
azimuth angle Ψ ;
i
– luminance non-uniformity (or luminance uniformity);
– eye point (eye relief);
– pivot rotation;
– type of LMD and aperture size;
– accuracy of sample stage; and
– correction methods for the measurement, if possible.
NOTE Some eyewear displays are designed as non-uniform displays to give priority to other features such as a
large FOV.
6.4 Chromaticity and colour gamut
6.4.1 General
The purpose of this method is to evaluate the chromaticity area and colour gamut of the DUT
as viewed from the eye point. In case of multi-primary displays, the gamut shall be measured
by the white and primary colours at the maximum input of the RGB channels in sequence, and
may also include a measurement of the secondary colours.
The standard measurement conditions (Clause 4), the standard coordinate system (5.1), the
measurement equipment (5.2) and the solid colour patterns (5.3.3) shall be applied. An LMD
that can measure colour quantities shall be used.
6.4.2 Measurement procedure
Measure the chromaticity of the DUT using the following procedure:
a) Move the entrance pupil of LMD at the eye point and adjust the optical axis of the LMD so
that it is orientated toward the DUT centre.
b) Display the full-screen pattern (white, red, green or blue) on the DUT. Allow the luminance
to stabilize.
, y ) for solid colour (p = W, R, G, B).
c) Measure the chromaticity coordinates (x
p p
d) Repeat from b) to measure each displayed pattern.
e) Repeat for the other ocular, if applicable.
6.4.3 Calculation
a) The CIE 1976 UCS chromaticity coordinates (u’, v’) for each primary pattern (R, G, B) are
calculated from the CIE 1931 chromaticity coordinates (x, y) as follows:
49x y
u′′, v
(4)
−+2xy12 + 3 −+2xy12 + 3
b) The colour gamut area metric is defined as the percent colour space area enclosed by the
colour gamut relative to the entire spectrum locus in the CIE 1976 UCS. It is calculated as
follows:
GA 256,1(u '− uv' )( '− v' )−(u '− uv' )( '− v' )
uv′′ R B G B G B R B
(5)
=
==
=
– 18 – IEC 63145-20-10:2019  IEC 2019
6.4.4 Report
The following items should be reported:
– CIE 1976 UCS chromaticity coordinates (u’ , v’ ) of white;
0 0
– CIE 1976 UCS chromaticity coordinates (u’ , v’ ) of each primary colour;
p p
– colour gamut area;
– eye point (eye relief);
– type of LMD and aperture size;
– accuracy of sample stage; and
– correction methods for the measurement, if possible.
6.5 Chromaticity uniformity
6.5.1 General
The purpose of this method is to evaluate the chromaticity uniformity of the DUT as applied to
the black and white checkerboard pattern, by positioning the entrance pupil of the LMD at the
eye point. The LMD will pivot at the entrance pupil to point to the desired virtual image
measurement position.
NOTE In case the pivoting point of the LMD is 10 mm behind the entrance pupil, this pivoting point can be used,
instead of the entrance pupil, to match the eye point of the DUT.
The standard measurement conditions (Clause 4), the standard coordinate system (5.1), the
measurement equipment (5.2) and the black and white checkerboard pattern (5.3.2) shall be
applied. An LMD that can measure colour quantities shall be used.
6.5.2 Measurement procedure
Use the same procedures as for luminous uniformity specified in 6.3.2 to measure the
chromaticity coordinates x and y at the multi-positions P instead of the luminance.
i i i
6.5.3 Calculation
a) The CIE 1976 UCS chromaticity coordinates (u’ , v’ ) are calculated from the CIE 1931

i i
chromaticity coordinates (x , y ) using Formula (4).
i i
b) Use the CIE 1976 chromaticity coordinates u’ , v’ at each location to determine the
i i
chromaticity distance between pairs of sampled colours using the following formula:
2 2
′′ ′ ′ ′ ′
∆=u v u− u+ v− v (6)
( ) ( )
j i ji
where i, j = 0 to 8, and i ≠ j. Chromaticity non-uniformity is defined as the largest sampled
chromaticity distance (∆u’v’) between any two points.
max
c) Repeat for the other ocular, if applicable.
6.5.4 Report
The following items should be reported:
– chromaticity non-uniformity (∆u’v’) ;
max
– CIE 1976 UCS chromaticity coordinates (u’ , v’ ) of each position P , with the elevation
i i i
angle α and the azimuth angle Ψ ;
i i
– eye point (eye relief);
– type of LMD and aperture size;
– accuracy of sample stage; and
– correction methods for the measurement, if possible.
6.6 Contrast ratio
6.6.1 General
The standard measurement conditions (Clause 4) the standard coordinate system (5.1) and
the measurement equipment (5.2) shall be applied. The 5 x 5 checkerboard pattern (5.3.2)
with white centre (corners) and with black centre (corners), respectively, shall be applied.
6.6.2 Measurement procedu
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