IEC 62629-52-1:2024

IEC 62629-52-1 ®
Edition 1.0 2024-01
INTERNATIONAL
STANDARD
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3D displays –
Part 52-1: Fundamental measurement methods of aerial display – Optical

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IEC 62629-52-1 ®
Edition 1.0 2024-01
INTERNATIONAL
STANDARD
colour
inside
3D displays –
Part 52-1: Fundamental measurement methods of aerial display – Optical

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 31.120; 31.260 ISBN 978-2-8322-8174-1

– 2 – IEC 62629-52-1:2024 © IEC 2024
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 (quantity symbols and units) . 8
4 Standard measurement conditions . 8
4.1 Standard environmental conditions . 8
4.2 Power supply . 8
4.3 Warm-up time . 8
4.4 Darkroom condition . 8
5 Measurement systems . 9
5.1 Measurement equipment . 9
5.1.1 Goniometer . 9
5.1.2 Light measuring device (LMD) . 9
5.2 Test patterns. 10
5.2.1 General . 10
5.2.2 Geometrical test pattern . 10
5.2.3 Solid colour patterns . 11
5.3 Measuring points . 11
5.4 Standard coordinate system . 11
6 Measurement methods for optical characteristics . 14
6.1 General . 14
6.2 Preparations . 15
6.3 Position and size of aerial image area and floating distance . 15
6.3.1 General . 15
6.3.2 Measurement procedure . 15
6.3.3 Calculation . 15
6.3.4 Report . 16
6.4 Luminance and luminance non-uniformity . 17
6.4.1 General . 17
6.4.2 Measurement procedure . 17
6.4.3 Calculation . 18
6.4.4 Report . 18
6.5 Contrast ratio . 19
6.5.1 General . 19
6.5.2 Measurement procedure . 19
6.5.3 Calculation . 20
6.5.4 Report . 20
6.6 Chromaticity and white chromaticity . 20
6.6.1 General . 20
6.6.2 Measuring procedures . 20
6.6.3 Calculation . 21
6.6.4 Reports. 21

6.7 Image luminance variation within the design viewing space . 21
6.7.1 General . 21
6.7.2 Measurement procedure . 21
6.7.3 Calculation . 22
6.7.4 Report . 22
Bibliography . 24

Figure 1 – Geometrical test pattern with vertical, horizontal and diagonal lines . 10
Figure 2 – Measuring points for the centre and multi-point measurement . 11
Figure 3 – Relation between the spherical coordinate system and the Cartesian
coordinate system . 12
Figure 4 – Definition of floating distance and end points of design viewing space of
aerial display . 14
Figure 5 – Measuring the aerial image positions . 17

Table 1 – Letter symbols (quantity symbols and units) . 8
Table 2 – Example of measurement results of luminance and luminance non-uniformity . 19
Table 3 – Example of measurement results of luminance and luminance non-uniformity
within the design viewing space . 23

– 4 – IEC 62629-52-1:2024 © IEC 2024
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
3D DISPLAYS –
Part 52-1: Fundamental measurement methods of aerial display – Optical

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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IEC 62629-52-1 has been prepared by IEC technical committee 110: Electronic displays. It is
an International Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
110/1593/FDIS 110/1616/RVD
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 International Standard 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 62629 series, published under the general title 3D displays, 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.
IMPORTANT – The "colour inside" logo on the cover page of this document 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 62629-52-1:2024 © IEC 2024
3D DISPLAYS –
Part 52-1: Fundamental measurement methods of aerial display – Optical

1 Scope
This part of IEC 62629 specifies the standard measurement methods and measurement
conditions for determining the optical properties of aerial displays. This document excludes
image quality of aerial displays, such as modulation transfer function (MTF) and resolution
measurements.
2 Normative references
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 62629-1-2:2021, 3D display devices – Part 1-2: Generic – Terminology and letter symbols
ISO/CIE 19476, Characterization of the performance of illuminance meters and luminance
meters
3 Terms, definitions, abbreviated terms and letter symbols
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in 62629-1-2 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
aerial display
display that forms a real image in mid-air by use of an incoherent light-source and a passive
optical component to converge diverging light from the light-source
Note 1 to entry: Details of aerial display, including the principles and typical optical components to form a real
image, are given in IEC TR 62629-51-1 [1].
[SOURCE: IEC 62629-1-2:2021, 3.1.20, modified – in the definition, the term "display" is
removed from the light source description because the light source is not limited to display, and
Note 1 has been expanded.]
3.1.2
aerial image area
two-dimensional area in mid-air where the aerial display exhibits information via electrically
generated images
3.1.3
design viewing space
three-dimensional space within which the user places both eyes and can see the entire aerial
image area
Note 1 to entry: Unlike the eye box of the eyewear display, the design viewing space of the aerial display usually
has no upper limit in the viewing distance; the width and height are quite larger than the interpupillary distance. Both
eyes of the viewer in the design viewing space will see the entire aerial image area meet a specified performance
metric.
3.1.4
design viewing position
design location at which the midpoint of both eyes is placed to achieve the optimal performance
when using an aerial display
Note 1 to entry: The design viewing position is not limited to the front centre of the aerial image area.
3.1.5
hardware reference point
design location on the aerial display hardware that is used for the origin of the coordinates
Note 1 to entry: The hardware reference point serves as the origin location of the measurement.
Note 2 to entry: The design viewing position is located along the line from the hardware reference point to the
centre of the aerial image area.
3.1.6
floating distance
distance from the centre of the aerial image area to the hardware reference point
3.1.7
design viewing distance
distance from the design viewing position to the centre of the aerial image area
Note 1 to entry: The summation of the design viewing distance and the floating distance becomes the distance
between the hardware reference point and the design viewing position.
3.2 Abbreviated terms
AIA aerial image area
CCD charge-coupled device
DUT device under test
DVP design viewing position
DVS design viewing space
HRP hardware reference point
LMD light measuring device
MTF modulation transfer function

– 8 – IEC 62629-52-1:2024 © IEC 2024
3.3 Letter symbols (quantity symbols and units)
The letter symbols for aerial displays are shown in Table 1.
Table 1 – Letter symbols (quantity symbols and units)
Quantities Symbols Units
P
Measuring point (i = 0: centre)
i
L
Luminance
v
cd/m
L
Maximum luminance
max cd/m
L
Minimum luminance
min cd/m
L
Average luminance (spatial)
va cd/m
Luminance non-uniformity NU
Contrast ratio CR
4 Standard measurement conditions
4.1 Standard environmental conditions
Unless otherwise specified, all tests and measurements for aerial displays shall be carried out
after sufficient warm-up time for the illumination sources and DUT (see 4.3), under the standard
environmental conditions as follows:
– temperature 25 °C ± 3 °C,
– relative humidity 25 % to 85 %, and
– atmospheric pressure 86 kPa to 106 kPa.
When different environmental conditions are used, they shall be noted in the report.
4.2 Power supply
In order to stabilize the performances of the DUT, the power supply for driving the DUT shall
be adjusted in accordance with the specification of the DUT.
NOTE When the DUT is driven by the battery, it is less susceptible to power supply fluctuations.
4.3 Warm-up time
The optical performances of the DUT can be affected by the temperature. It takes a certain time
for the luminance output of the DUT to achieve a steady state. If the luminance output is not
within ±3 % variation, it shall be reported. All measuring conditions shall be kept constant during
the measurements.
NOTE If the measuring result does not become steady state, it might be influenced by the output fluctuation of the
DUT or fluctuation of the LMD such as noise, or both.
4.4 Darkroom condition
The luminance contribution from the background in the test room reflected off the measurement
space shall be less than 1/20 of 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 Measurement equipment
5.1.1 Goniometer
A biaxial goniometer shall be assembled to be capable of measuring the azimuth (horizontal)
and elevation (vertical) angles. The angular accuracy should be 0,1° or less. A translation stage
can be applied to move the position of the biaxial goniometer.
5.1.2 Light measuring device (LMD)
The configurations and operating conditions of the equipment should comply with the structures
specified in each item. To ensure the accurate measurements, the following requirements shall
be applied. Otherwise, the differences shall be noted in the report. ISO/CIE 19476 is available
for reference to the LMD evaluation procedures.
The optics of the LMD (a spot LMD or a 2D imaging LMD) shall be equivalent to the human eye.
The LMD shall be equipped with the finder. The position of the entrance pupil (aperture) of the
LMD shall be provided by the manufacturer or the supplier. The entrance pupil size of the LMD
should be set between 2 mm and 5 mm. 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 veiling glare and lens flare (i.e., scatters in the LMD optical system);
– timing of data-acquisition, low-pass filtering and aliasing-effects;
– linearity of detection and data-conversion;
– measurement field size (number of the image pixels).
The LMD shall be located on the goniometer. The goniometer rotation centre shall be located
at the centre of the LMD entrance pupil.
NOTE 1 If the eye box is small and the influence of the eye-ball rotation is taking place, the rotation centre of the
gon
...