IEC 63181-2:2020

LCD multi-screen display terminals - Part 2: Measuring methods

IEC 63181-2:2020 specifies measuring methods for LCD multi-screen display terminals. To evaluate the characteristics of LCD multi-screen display terminals, the following measurement items are specified:
– gap (physical, optical): detailed splicing precision;
– splicing deviation: splicing accuracy of active areas of LCD splicing screen;
– installation deviation: the flatness of terminal surfaces in vertical and horizontal directions;
– luminance uniformity: luminance uniformity of adjacent LCD units;
– chromatic uniformity: chromatic uniformity of adjacent LCD units.

Terminaux d'affichage à plusieurs écrans LCD - Partie 2: Méthodes de mesure

L'IEC 63181-2:2020 spécifie les méthodes de mesure des terminaux d'affichage à plusieurs écrans LCD. Pour évaluer les caractéristiques des terminaux d'affichage à plusieurs écrans LCD, les éléments de mesure suivants sont spécifiés:
– écartement (physique, optique): précision de raccordement détaillée;
– écart de raccordement: précision de raccordement des zones actives de l'écran de raccordement LCD;
– écart d'installation: la planéité des surfaces du terminal dans le sens vertical et le sens horizontal;
– uniformité de la luminance: uniformité de luminance des unités LCD adjacentes;
– uniformité chromatique: uniformité chromatique des unités LCD adjacentes.

General Information

• Status: Published
• Publication Date: 10-Jun-2020
• ICS: 31.120 - Electronic display devices
• Technical Committee: TC 100 - Audio, video and multimedia systems and equipment
• Drafting Committee: PT 63181 - TC 100/PT 63181
• Current Stage: PPUB - Publication issued
• Start Date: 11-Jun-2020
• Completion Date: 26-Jun-2020

Overview

IEC 63181-2:2020 is an international standard developed by the International Electrotechnical Commission (IEC) that specifies measuring methods for LCD multi-screen display terminals. This document is crucial for manufacturers, quality control professionals, and system integrators involved in the design, production, and evaluation of multi-screen LCD display setups. The standard establishes precise methodologies for assessing the mechanical and optical integrity of LCD splicing screens, ensuring consistent performance and user experience.

Key Topics

The standard defines detailed measurement methods across several important aspects of LCD multi-screen display terminals:

• Gap Measurement (Physical and Optical):

  • Physical gap refers to the actual measurable space between adjacent LCD units’ edges, assessed using feeler gauges.
  • Optical gap is the space between the active display areas of adjacent LCD units, measured with callipers under a full white screen condition.

• Splicing Deviation:

  • This measures the pixel-level displacement between active areas of adjacent LCD units to determine the accuracy of image alignment across the multi-screen terminal.
  • Testing involves input of custom test signals (graduation and circle) and analysis of display continuity.

• Installation Deviation:

  • Evaluates the flatness of multi-screen display terminal surfaces in both vertical and horizontal directions, ensuring a smooth and even terminal interface.

• Luminance Uniformity:

  • Measures the consistency of brightness across adjacent LCD units to ensure uniform display output without noticeable variation.
  • Uses specific luminance measurement points and calculations to assess uniformity.

• Chromatic Uniformity:

  • Assesses color consistency between adjacent LCD units, critical for visual quality in video walls and multi-screen displays.
  • Measurement focuses on center points and edge-centre points of adjacent units.

• Standard Environmental Conditions:

  • All measurements are conducted under controlled settings: temperature around 25 ± 3 °C, relative humidity between 25% and 85%, atmospheric pressure 86-106 kPa, and ambient illuminance ≤ 1 lx.

• Measurement Distances:

  • The standard recommends two options for measurement: non-contact distance set at three times the height of a single LCD unit, or direct-contact measurement.

Applications

IEC 63181-2:2020 plays an essential role in the following areas:

• Manufacturing Quality Control: Ensuring consistency in LCD multi-screen terminal assembly with precise splicing accuracy and proper installation.
• Display Wall Assembly: Assisting integrators in configuring multi-screen LCD setups with minimal splicing deviation and high luminance/chromatic uniformity.
• Performance Evaluation: Providing standardized testing methods for manufacturers and customers to evaluate splicing precision and optical-electrical performance.
• Product Development: Guiding engineers in designing multi-screen displays with improved physical and optical alignment, contributing to enhanced user experience in digital signage, command centers, and multimedia installations.

By applying these standardized measuring methods, stakeholders can ensure that LCD multi-screen display terminals meet rigorous quality criteria and operate optimally in diverse environments.

Related Standards

• IEC TS 63181-1: LCD multi-screen display terminals – Part 1: Conceptual model
  This related technical specification provides definitions, models, and terminology used in the series, supporting consistent understanding and application of the measurement methods defined in IEC 63181-2.

• Other IEC standards on display technology may provide complementary guidelines on display characteristics and electrical safety.

---

Keywords: IEC 63181-2:2020, LCD multi-screen display terminals, measurement methods, physical gap, optical gap, splicing deviation, installation deviation, luminance uniformity, chromatic uniformity, LCD splicing screen, international standard, display wall quality assessment, LCD measurement standards.

Standards Content (Sample)

IEC 63181-2 ®
Edition 1.0 2020-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
LCD multi-screen display terminals –
Part 2: Measuring methods
Terminaux d'affichage à plusieurs écrans LCD –
Partie 2: Méthodes de mesure
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IEC 63181-2 ®
Edition 1.0 2020-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
LCD multi-screen display terminals –

Part 2: Measuring methods
Terminaux d'affichage à plusieurs écrans LCD –

Partie 2: Méthodes de mesure
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 31.120 ISBN 978-2-8322-8444-5

– 2 – IEC 63181-2:2020 © IEC 2020
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Measuring conditions . 5
4.1 Standard measuring environmental conditions . 5
4.2 Optical measuring distance . 6
5 Measurement methods of structure test for LCD multi-screen display terminals . 6
5.1 Physical gap . 6
5.1.1 General . 6
5.1.2 Method of measurement . 6
5.2 Optical gap . 7
5.2.1 General . 7
5.2.2 Method of measurement . 7
5.3 Splicing deviation . 7
5.3.1 General . 7
5.3.2 Method of measurement . 8
5.4 LCD multi-screen display terminals installation deviation . 8
5.4.1 General . 8
5.4.2 Method of measurement . 9
6 Measuring methods of LCD multi-screen display terminals' optical-electrical
performance . 10
6.1 Measuring methods of LCD multi-screen display terminals' luminance –
uniformity . 10
6.1.1 LCD splicing screen luminance uniformity . 10
6.1.2 Luminance uniformity of adjacent LCD units . 11
6.2 Measuring methods of chromatic uniformity for LCD splicing screen . 13
6.2.1 Chromatic uniformity of centre points of LCD units . 13
6.2.2 Chromatic uniformity of adjacent edge-centre points of adjacent LCD
units . 13
Bibliography . 15

Figure 1 – Illustration for physical gap and optical gap . 7
Figure 2 – Illustration for test signal . 8
Figure 3 – Illustration for diagonal distances . 9
Figure 4 – Illustration for ∠EBD . 10
Figure 5 – Illustration for testing units . 11
Figure 6 – Example for luminance measurements of edge-centre point pairs . 12

Table 1 – Example for luminance performance calculation of edge-centre point pairs
P . 13
1~4
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LCD MULTI-SCREEN DISPLAY TERMINALS –

Part 2: Measuring methods
FOREWORD
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International Standard IEC 63181-2 has been prepared by IEC technical committee 100:
Audio, video and multimedia systems and equipment.
The text of this International Standard is based on the following documents:
FDIS Report on voting
100/3413/FDIS 100/3441/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 63181 series, published under the general title LCD multi-screen
display terminals, can be found on the IEC website.

– 4 – IEC 63181-2:2020 © IEC 2020
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.
LCD MULTI-SCREEN DISPLAY TERMINALS –

Part 2: Measuring methods
1 Scope
This part of IEC 63181 specifies measuring methods for LCD multi-screen display terminals.
To evaluate the characteristics of LCD multi-screen display terminals, the following
measurement items are specified:
– gap (physical, optical): detailed splicing precision;
– splicing deviation: splicing accuracy of active areas of LCD splicing screen;
– installation deviation: the flatness of terminal surfaces in vertical and horizontal directions;
– luminance uniformity: luminance uniformity of adjacent LCD units;
– chromatic uniformity: chromatic uniformity of adjacent LCD units.
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 TS 63181-1, LCD multi-screen display terminals – Part 1: Conceptual model
3 Terms and definitions
For the purposes of this document, the terms and definitions defined in IEC TS 63181-1 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
4 Measuring conditions
4.1 Standard measuring environmental conditions
Measurements shall be carried out under the following standard environmental conditions:
• Temperature: (25 ± 3) °C;
• Relative humidity: 25 % RH to 85 % RH;
• Atmospheric pressure: 86 kPa to 106 kPa;
• Illuminance range: ≤ 1 lx.
When different environmental conditions are applied, they shall be noted in the measurement
report.
– 6 – IEC 63181-2:2020 © IEC 2020
4.2 Optical measuring distance
Two measurement distance options are provided to perform the measurement:
– Option 1 (recommended): non-contact measurement
In this option, the measurement distance shall be set to 3 times the height of a single LCD
unit; the measurement device shall be perpendicular to the test point(s) during the entire
measurement.
– Option 2: contact measurement
In this option, there is no measurement distance between the LCD units and the
measurement device, which means that the measurement device is in direct contact with
the surface of the LCD units at the test point(s) during the entire measurement.
5 Measurement methods of structure test for LCD multi-screen display
terminals
5.1 Physical gap
5.1.1 General
The purpose of this test is to measure the gap(s) between adjacent screen sides for all the
adjacent LCD units.
5.1.2 Method of measurement
Apply a feeler gauge(s) to measure the gap(s) between the adjacent screen sides for all the
adjacent LCD units. The physical gap is the largest measurement recorded (see Figure 1).

Key
V , H the optical gap
1 1
V , H the physical gap
2 2
NOTE This figure shows a 2-by-2 LCD unit matrix as an example only. The relevant requirements are compatible
for an m-by-n LCD unit matrix, with m + n > 2.
Figure 1 – Illustration for physical gap and optical gap
5.2 Optical gap
5.2.1 General
The purpose of this test is to measure the gap(s) between adjacent active area boundaries for
all the adjacent LCD units.
5.2.2 Method of measurement
a) Input a full white signal to the LCD multi-screen display terminals, set all LCD units of the
LCD splicing screen to standard states that are factory default settings or manufacturer-
specified settings.
b) Use a calliper to measure the gap(s) between adjacent active area boundaries for all the
adjacent LCD units; record the largest measurement as the optical gap (see Figure 1).
5.3 Splicing deviation
5.3.1 General
The purpose of this test is to measure the displacement of active areas (in pixels) of an LCD
splicing screen.
– 8 – IEC 63181-2:2020 © IEC 2020
5.3.2 Method of measurement
a) Set all LCD units in the LCD splicing screen to standard states that are factory default
settings or manufacturer-specified settings.
b) Input a signal which is composed of a graduation and a circle. Then, let the signal roam
over each group of the 2-by-2 (1-by-2 or 2-by-1 are acceptable when 2-by-2 is not
possible) LCD units in the LCD splicing screen, without any overlaps for any adjacent
groups.
c) Preliminarily, measure the effect of the circle signal over the whole group (see Figure 2 a)).
d) Accurately measure the displacement of the adjacent active area boundaries in the
vertical and horizontal directions of the LCD units with the partial graduation signal (see
Figure 2 b).
a) Test signal
b) Partial test signal
Figure 2 – Illustration for test signal
5.4 LCD multi-screen display terminals installation deviation
5.4.1 General
The purpose of this test is to verify the flatness and installation deviation of LCD multi-screen
display terminals, including diagonal deviation, edge flatness, LCD splicing screen display
surface flatness, vertical installation deviation.

5.4.2 Method of measurement
a) Define the four corners of the LCD splicing screen as A, B, C, D (see Figure 3).
b) Measure the edge lengths of AB, BD, CD, AC, compare the lengths of AB and CD with the
width of the LCD splicing screen without installation deviation, record the differences as
ΔL and ΔL ; compare AC and BD with the accurate height of the LCD splicing
width,1 width,2
screen without installation deviation, record the differences as ΔL and ΔL .
height,1 height,2
The differences correspond to the flatness of the edges.
c) Measure and record the length of AD and BC. Then, measure the LCD splicing screen
display surface flatness by calculating the length differences of AD and BC as
ΔLL− L in part b), with the assumption that all the outer edges of LCD splicing
AD BC
screen are aligned. If Δ0L≠ , it means that the surface of the LCD splicing screen is not
flat.
d) Hang a vertical plumb from point B, measure and calculate ∠EBD in degrees, which is the
LCD splicing screen's vertical installation deviation (see Figure 4).

NOTE 1 A, B, C, D are the four vertexes of the LCD splicing screen.
NOTE 2 The ideal gap between LCD units at any installation for calculation is 0.
NOTE 3 This figure shows a 2-by-2 LCD unit matrix as an example only. The relevant requirements are
compatible for an m-by-n LCD unit matrix, with m + n > 2.
Figure 3 – Illustration for diagonal distances
=
– 10 – IEC 63181-2:2020 © IEC 2020

Key
a ∠EBD, the angle between BE and BD
NOTE This figure shows a 2-by-2 LCD unit matrix as an example only. The relevant requirements are compatible
for an m-by-n LCD unit matrix, with m + n > 2.
Figure 4 – Illustration for ∠EBD
6 Measuring methods of LCD multi-screen display terminals' optical-electrical
performance
6.1 Measuring methods of LCD multi-screen display terminals' luminance –
uniformity
6.1.1 LCD splicing screen luminance uniformity
6.1.1.1 General
The purpose of this test is to verify the luminance uniformity of the LCD splicing screen
through each LCD unit in the LCD splicing screen. This test procedure is modified from
IEC 61747-30-1:2012, 6.7.3.2.
6.1.1.2 Method of measurement
a) Input a full white signal to LCD splicing screen, set all LCD units of LCD splicing screen to
standard states that are factory default settings or manufacturer-specified settings.
b) Use a light measurement device (LMD) to measure the centre point luminance for all LCD
units and record as L with i= 1,2,3,. (see Figure 5).
i
c) Calculate the average luminance of the LCD splicing screen (see Formula (2));
d) Calculate the luminance uniformity of LCD splicing screen (see Formula (1) with
U
lum
result expressed as a percentage).
L

i=1,2,3.
U = Max (1)

lum
L
ave
n
LL=
(2)
∑
ave
i=1,2,3,. i
n
where
L is the LCD multi-screen display terminals' average luminance;
ave
n is the total number of LCD units.

W
Key
W represents the full width of each LCD unit
H represents the full height of each LCD unit
NOTE This figure shows a 3-by-3 LCD unit matrix as an example only. The relevant requirements are compatible
for an m-by-n LCD unit matrix, with m + n > 2.
Figure 5 – Illustration for testing units
6.1.2 Luminance uniformity of adjacent LCD units
6.1.2.1 General
The purpose of this test is to verify luminance uniformity of all adjacent LCD units in an LCD
splicing screen.
For all measurements in 6.1.2, to make the measurement methods easily understood, the 3-
by-3 LCD splicing screen is provided as an example (see Figure 6). The actual measurements
shall be made at all adjacent edge-centre point pairs of all LCD units in an m-by-n LCD
splicing screen. Each adjacent edge-centre point pair shall be tested once only, or the
duplicate values will have an effect on the accuracy of the final result.
6.1.2.2 Method of measurement
a) Set all LCD units to standard states that are factory default settings or manufacturer-
specified settings, and ensure the LCD splicing screen displays a full white signal.
b) Use an LMD to measure the luminance of each pair of adjacent edge-centre points for all
pairs P, record and sort the luminance values as ( L , L ) for each pair P
adj,1 adj,2
(see Figure 6).
c) Compare luminance in each pair of adjacent edge-centre points for all pairs P, record and
calculate luminance uniformity all non-redundant adjacent pairs of LCD units U with
adj
Formula (3) and Formula (4) (see Table 1 for the calculation example of P ).
1~4
– 12 – IEC 63181-2:2020 © IEC 2020
Max(LL, )− L Min(LL, )− L
P,n P,n
adj,1 adj,2 adj,1 adj,2
U 1− or 1− (3)
adj
L L
P,n P,n
where
n is the identity number of the adjacent edge-centre points pair P, n = 1,2,3…
LL+
adj,1 adj,2
(4)
LP,n=
where
n is the identity number of the adjacent edge-centre points pair P, n = 1,2,3…

Key
W represents the full width of each LCD unit
H represents the full height of each LCD unit
Luminance values of the adjacent edge-centre points pairs P shall be measured for this example.
1~12
NOTE The distance of all edge-centre points to the corresponding edges are either 1/9 height of a single LCD unit
or 1/9 width of a single LCD unit. Based on the distances in IEC 60107-1:1997, Figure 82.
Figure 6 – Example for luminance measurements of edge-centre point pairs
=
Table 1 – Example for luminance performance calculation
of edge-centre point pairs P
1~4
Example P P P P
1 2 3 4
pairs
Parameters
L L L L L L L L
adj,1 adj,2 adj,1 adj,2 adj,1 adj,2 adj,1 adj,2
Data xx xx xx xx xx xx xx xx
Max (or Min)
M M M M
P,1 P,2 P,3 P,4
in each pair
= Max( L , L ) or = Max( L , L ) or = Max( L , L ) or = Max( L , L ) or
adj,1 adj,2 adj,1 adj,2 adj,1 adj,2 adj,1 adj,2
L , L ) L , L ) L , L ) L , L )
= Min( = Min( = Min( = Min(
adj,1 adj,2 adj,1 adj,2 adj,1 adj,2 adj,1 adj,2
Average
luminance
LL+ LL+ LL+ LL+
adj,1 adj,2 adj,1 adj,2 adj,1 adj,2 adj,1 adj,2
L = L = L = L =
P,1 P,2 P,3 P,4
L of each
P 2 2 2 2
pair
Luminance
uniformity
ML+ ML+ ML+ ML+
P,1 P,2 P,3 P,4
P,1 P,2 P,3 P,4
1− 1− 1− 1−
U of each
adj
L L L L
P,1 P,2 P,3 P,4
pair
In row 4, for each edge-centre points pair, if the measurement purpose is to measure the performance difference
between the Max value and the average value, choose the Max value; otherwise, choose the Min value.
Alternatively, report the maximum value from the U of all pairs as the final result.
adj
6.2 Measuring methods of chromatic uniformity for LCD splicing screen
6.2.1 Chromatic uniformity of centre points of LCD units
6.2.1.1 General
The purpose of this test is to verify the chromatic deviations for all LCD unit centre points in
an LCD splicing screen. This test procedure is modified from IEC 61747-30-1:2012, 6.7.5.2.
6.2.1.2 Method of measurement
a) Set all LCD splicing units to standard states that are factory default settings or
manufacturer-specified settings, and ensure the LCD splicing screen displays a full white
signal.
b) Use an LMD to measure the chromatic coordinates ( u , v ) with i= 1,2,3,. , for all
c,i c,i
centre points of the LCD units (see Figure 5).
c) Set one of the pairs of ( u , v ) as the overall reference pair ( u , v ), calculate the
c,i c,i 0 0
chromatic uniformity Δuv for the LCD splicing screen (see Formula (5)):
c
(5)

Δuv Maxu−u+−v v
( ) ( )
c c,ii0 c, 0


6.2.2 Chromatic uniformity of adjacent edge-centre points of adjacent LCD units
6.2.2.1 General
The purpose of this test is to verify the chromatic uniformity of edge-centre point pairs for all
adjacent edge pairs of all LCD units in the LCD splicing screen.
=
– 14 – I
...