SJ/T 11281-2017 English PDF (SJT11281-2017)

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SJ/T 11281-2017: Measure methods of light emitting diode (LED) displays
SJ/T 11281-2017
SJ
ELECTRONICS INDUSTRY STANDARD
ICS 31.120
L 47
Filing No..
Replacing SJ/T 11281-2007
Measure methods of light emitting diode (LED) displays
ISSUED ON. NOVEMBER 07, 2017
IMPLEMENTED ON. JANUARY 01, 2018
Issued by. Ministry of Industry and Information Technology of PRC
Table of Contents
Foreword... 3
1 Scope... 5
2 Normative references... 5
3 Terms, definitions, symbols... 5
4 General requirements... 5
5 Test method... 7
Appendix A (Normative) The slope of the constant dominant wavelength line of the
CIE 1931 chromaticity diagram standard illuminant E (equal energy light source)... 31
Appendix B (Normative) Supporting test software... 35
Measure methods of light emitting diode (LED) displays
1 Scope
This standard specifies the test methods for the mechanical, optical, electrical and other
main technical performance parameters of light-emitting diode (LED) display.
This standard applies to the test of light-emitting diode (LED) display (hereinafter
referred to as display).
2 Normative references
GB 4208 Degrees of protection provided by enclosure (IP code)
SJ/T 11141-2017 Generic specification for LED displays
CIE 1931 Chromaticity diagram
3 Terms, definitions, symbols
The terms, definitions, symbols as established in SJ/T 11141-2017 apply to this standard.
4 General requirements
4.1 Test conditions
4.1.1 Atmospheric conditions
Unless otherwise specified, the test conditions are as follows.
a) Ambient temperature. 15 °C ~ 35 °C;
b) Relative humidity. 20%RH ~ 80%RH;
c) Atmospheric pressure. 86 kPa ~ 106 kPa.
4.1.2 Standard atmospheric conditions for arbitration test
Unless otherwise specified, the standard atmospheric conditions for arbitration test are
as follows.
a) Ambient temperature. 25 °C ± 1 °C;
b) Relative humidity. 48%RH ~ 52%RH;
c) Atmospheric pressure. 86 kPa ~ 106 kPa.
4.1.3 Other environmental conditions
Unless otherwise specified, other environmental conditions shall comply with the
following provisions.
a) AC power supply. (220 ± 22) V, (50 ± 1) Hz;
b) Recommended computer configuration. Mainstream computer hardware
configuration, Windows operating system, graphics card with DVI output;
c) The measurement environment shall be free of mechanical vibration,
electromagnetic, photoelectric interference that may affect the test accuracy;
d) The display shall be debugged to the best state before testing; the configuration
parameters and working state of the display shall not be changed during the test;
e) Before the photoelectric performance test of the display, all light-emitting diodes
shall be lit at 30% of the maximum brightness; the preheating time shall be no
less than 15 minutes.
4.2 Test instruments and software
Unless otherwise specified, the performance of all test instruments shall meet the
specific requirements of the test.
a) Color analyzer (similar instruments for measuring optical properties such as
brightness and chromaticity are also acceptable);
b) Light intensity meter;
c) Illuminance meter;
d) Oscilloscope. Bandwidth not less than DC ~ 100 MHz;
e) Vernier caliper. Graduation value 0.02 mm;
d) Feeler gauge. Graduation value 0.01 mm;
f) Protractor. Graduation value 1°;
g) Steel ruler. Length 1 m;
h) Vibration table. Amplitude greater than 2 mm, resonant frequency 1 Hz ~ 500 Hz,
vibration direction vertical and horizontal;
c) Place the display module to be tested on the bracket; use the geometric center of
the measured area as the axis, to keep the bracket horizontal; rotate it to the left
and right sides respectively, keeping the color analyzer probe always aimed at the
original measured area. When the brightness value drops to LF/2, use a protractor
to measure the angle θSX of the bracket rotation;
d) Measure the horizontal viewing angle of each primary color in the same way; take
the minimum value as the horizontal viewing angle θS of the display.
5.2.2.4.2 Vertical viewing angle
Measure as follows.
a) Place the LED on a bracket by rotating it 90° clockwise facing the LED emitting
surface;
b) Same as 5.2.2.4.1.a);
c) Same as 5.2.2.4.1.b);
d) Same as 5.2.2.4.1.c);
e) Measure the vertical viewing angle of each primary color in the same way; take
the minimum value as the vertical viewing angle θC of the display.
5.2.3 Maximum contrast
5.2.3.1 Purpose
Measure the maximum contrast of the display under specified conditions.
5.2.3.2 Measurement principle
Same as 5.2.1.
5.2.3.3 Measurement conditions
The measurement conditions are as follows.
a) The illuminance in the normal direction of the indoor display is 10 × (1 ± 10%)
lx;
b) The illuminance in the normal direction of the outdoor display is 5000 × (1 ± 10%)
lx;
c) The acquisition range of the color analyzer shall not be less than 16 adjacent pixels.
5.2.3.4 Measurement steps
g) The maximum value is the brightness uniformity LMJ of the display module of the
screen.
5.2.7.3 Display module brightness uniformity
5.2.7.3.1 Purpose
Measure the brightness consistency between modules in the same display.
5.2.7.3.2 Measurement principle
Same as 5.2.1.2.
5.2.7.3.3 Measurement conditions
The measurement conditions are as follows.
a) The change in ambient illumination is less than ±10%;
b) The acquisition range of the color analyzer shall not be less than 16 adjacent pixels.
5.2.7.3.4 Measurement steps
Measurement is carried out according to the following steps.
a) During the measurement process, the angle between the observation line and the
display remains unchanged;
b) 9 display modules are randomly selected within the full screen range (9 display
modules are randomly selected in the black screen state);
c) At the highest grayscale level and the highest brightness level, a primary color is
displayed on the full screen;
d) The brightness values of the 9 display modules are measured by a color analyzer;
then the arithmetic mean is calculated;
e) The brightness uniformity LMJ of the primary color display module of the display
is calculated by formula (9).
Where.
LMJ - Brightness uniformity of the display module;
L - Brightness of the display module, in candela per square meter (cd/m2);
- Arithmetic mean of the brightness of the 9 display modules, i.e.
, in candela per square meter (cd/m2).
f) Using the same method, measure and calculate the three primary colors of red,
green, blue respectively;
g) The maximum value is the brightness uniformity LMJ of the display module of the
screen.
5.3 Electrical performance
5.3.1 Frame frequency
5.3.1.1 Purpose
Measure the update frequency of the screen information on the display.
5.3.1.2 Measurement principle
Make a special test video, which sets different graphics frame by frame. The number of
different graphics that can be displayed on the display is the frame frequency.
5.3.1.3 Measurement conditions
The measurement conditions are as follows.
a) The size of the display meets the requirements of the test software
b) The computer installed with test software outputs graphics to the display.
5.3.1.4 Measurement steps
Perform the measurement as follows.
a) Start the test software; select the frame rate test function (see Appendix B); set an
area on the display, ...