Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces SJ/T 11281-2007 Measure methods of light emitting diode (LED) panels.
The following main changes have been made with respect to SJ/T 11281-2007:
——The version number of the standards cited in the “normative references” are modified (see clause 2);
——The relative humidity in the “measure conditions” is modified (see 4.1);
——The measure methods for “refresh ratio” are modified (see 5.3.2);
——The measure methods for “duty ratio” are deleted (see 4.3.2 and 4.3.3 of Edition 2007);
——The measure methods for "automatic adjustment of luminance of displays” are added (see 5.3.6);
——The table of grading of each parameter index is deleted (see 4.1.1.1, 4.1.2.1.2, 4.1.2.2.2, 4.1.2.3.2, 4.1.2.4.2, 4.2.4.2, 4.2.6.2, 4.2.7.1.2, 4.2.7.2.2, 4.2.7.3.2, 4.3.1.2, 4.3.2.2 and 4.3.7.2 of Edition 2007)
——Other editorial changes and text corrections.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The issuing body of this document shall not be held responsible for identifying any or all such patent rights.
This standard is under the jurisdiction of the China Electronics Standardization Institute (CESI) of Ministry of Industry and Information Technology.
The previous editions of this standard are as follows:
——SJ/T 11281-2003;
——ST/T 11281-2007.
Measure methods of light emitting diode (LED) displays
1 Scope
This standard specifies the measure methods for the parameters of main technical properties, such as mechanical property, optical property and electrical property, of LED displays.
This standard is applicable to the measurement of light emitting diode displays (hereinafter referred to as displays).
2 Normative references
The following referenced documents are indispensable for the application 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.
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 and symbols
For the purposes of this standard, the terms, definitions and symbols given in GB/T 11141-2017 apply.
4 General requirements
4.1 Test conditions
4.1.1 Atmospheric conditions
Unless otherwise specified, the measure conditions shall be as follows:
a) ambient temperature: 15℃~35℃;
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 shall be as follows:
a) ambient temperature: 25℃±1℃;
b) relative humidity: 48％RH~52％RH;
c) atmospheric pressure: 86kPa~106kPa.
4.1.3 Other environmental conditions
Unless otherwise specified, other environmental conditions shall meet the following requirements:
a) AC power supply: (220±22) V, (50±1) Hz.
b) Recommended computer configuration: mainstream computer hardware, Windows operating system, and graphics card with DVI output;
c) The measurement environment shall be free from mechanical vibration, electromagnetic and photoelectric interferences that will affect the accuracy of the measurement;
d) The display screen shall be debugged to the optimal state before the measurement, and the configuration parameters and working state of the displays shall not be changed during the measurement;
e) Before the photoelectric performance test of the displays, all light-emitting diodes shall be lit at 30% of the highest luminance, with the preheating time not less than 15min.
4.2 Instruments and software for measurement
Unless otherwise specified, the performance of all instruments and apparatus for measurement shall meet the specific requirements for measurement:
a) color analyzer (similar instruments for measuring optical properties such as luminance and chromaticity may also be used);
b) light intensity meter;
c) illuminometer;
d) oscilloscope: with the width of frequency band not less than DC~100 MHz;
e) vernier caliper: with a division value of 0.02 mm;
d) feeler gauge: with a division value of 0.01 mm;
f) protractor: with a division value of 1°;
g) steel ruler: with a length of 1m;
h) vibration table: with an amplitude greater than 2 mm, a resonance frequency of 1 Hz~500 Hz, and vibration directions being vertical and horizontal;
i) thermometer;
j) photoelectric sensor: with a frequency response greater than 50 MHz;
k) test software: meeting the actual measurement requirements.
Note: The uncertainty of measuring equipment shall meet the technical requirements of relevant specifications and be verified as qualified. In the verification cycle, measurement shall be carried out according to the relevant operating procedures.
5 Measurement method
5.1 Mechanical property
5.1.1 Degree of protection provided by enclosure
It shall be measured according to the method given in GB 4208.
5.1.2 Assembly accuracy
5.1.2.1 Level up degree
5.1.2.1.1 Purpose
To measure the level up degree of LED displays assembly.
5.1.2.1.2 Measurement principle
See Figure 1 for the principle of concave measurement.
Figure 1
See Figure 2 for the principle of convex measurement.
Figure 2
5.1.2.1.3 Measurement conditions
Disconnect the display under measurement from the power supply, so that it is in black screen state.
5.1.2.1.4 Measurement steps
Measurement shall be carried out by following the steps below:
a) Place a 1 m long steel ruler at any position on the surface of the display;
b) For the measurement of concave, according to the method shown in Figure 1, the maximum gap, H, between the steel ruler and the surface of the displays shall be measured by the feeler gauge, which is the level up degree, P;
c) For the measurement of convex, according to the method shown in Figure 2, the maximum gap, H, between the steel ruler and the surface of the displays shall be measured by the feeler gauge, and the level up degree equals to H/2;
5.1.2.2 Relative deviation of pixel pitch
5.1.2.2.1 Purpose
To measure the center distance between any adjacent pixels, and calculate the relative deviation of the measured center distance from the nominal value using equation.
5.1.2.2.2 Measurement principle
See Figures 3 and 4 for the measurement principle for relative deviation of pixel pitch.
a) b)
Figure 3
5.1.2.2.3 Measurement conditions
Disconnect the display under measurement from the power supply, so that it is in black screen state.
5.1.2.2.4 Measurement steps
Measurement shall be carried out by following the steps below:
a) For a pixel composed of multiple LEDs, LEDs at the same position in two pixels shall be found out, and the pixel pitch shall be measured using a general measuring tool with a division value of 0.02mm according to the method shown in Figure 3;
b) For a pixel composed of a single LED, the pixel pitch shall be measured using a general measuring tool with a division value of 0.02mm according to the method shown in Figure 4;
Foreword i
1 Scope
2 Normative references
3 Terms, definitions and symbols
4 General requirements
5 Measurement method
5.1 Mechanical property
5.2 Optical properties
5.3 Electrical performance
Annex A (Normative) Slope of constant main wavelength line of standard light source E (equal-energy light source) in CIE 1931 chromaticity diagram
Annex B (Normative) Supporting test software
Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard replaces SJ/T 11281-2007 Measure methods of light emitting diode (LED) panels.
The following main changes have been made with respect to SJ/T 11281-2007:
——The version number of the standards cited in the “normative references” are modified (see clause 2);
——The relative humidity in the “measure conditions” is modified (see 4.1);
——The measure methods for “refresh ratio” are modified (see 5.3.2);
——The measure methods for “duty ratio” are deleted (see 4.3.2 and 4.3.3 of Edition 2007);
——The measure methods for "automatic adjustment of luminance of displays” are added (see 5.3.6);
——The table of grading of each parameter index is deleted (see 4.1.1.1, 4.1.2.1.2, 4.1.2.2.2, 4.1.2.3.2, 4.1.2.4.2, 4.2.4.2, 4.2.6.2, 4.2.7.1.2, 4.2.7.2.2, 4.2.7.3.2, 4.3.1.2, 4.3.2.2 and 4.3.7.2 of Edition 2007)
——Other editorial changes and text corrections.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The issuing body of this document shall not be held responsible for identifying any or all such patent rights.
This standard is under the jurisdiction of the China Electronics Standardization Institute (CESI) of Ministry of Industry and Information Technology.
The previous editions of this standard are as follows:
——SJ/T 11281-2003;
——ST/T 11281-2007.
Measure methods of light emitting diode (LED) displays
1 Scope
This standard specifies the measure methods for the parameters of main technical properties, such as mechanical property, optical property and electrical property, of LED displays.
This standard is applicable to the measurement of light emitting diode displays (hereinafter referred to as displays).
2 Normative references
The following referenced documents are indispensable for the application 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.
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 and symbols
For the purposes of this standard, the terms, definitions and symbols given in GB/T 11141-2017 apply.
4 General requirements
4.1 Test conditions
4.1.1 Atmospheric conditions
Unless otherwise specified, the measure conditions shall be as follows:
a) ambient temperature: 15℃~35℃;
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 shall be as follows:
a) ambient temperature: 25℃±1℃;
b) relative humidity: 48％RH~52％RH;
c) atmospheric pressure: 86kPa~106kPa.
4.1.3 Other environmental conditions
Unless otherwise specified, other environmental conditions shall meet the following requirements:
a) AC power supply: (220±22) V, (50±1) Hz.
b) Recommended computer configuration: mainstream computer hardware, Windows operating system, and graphics card with DVI output;
c) The measurement environment shall be free from mechanical vibration, electromagnetic and photoelectric interferences that will affect the accuracy of the measurement;
d) The display screen shall be debugged to the optimal state before the measurement, and the configuration parameters and working state of the displays shall not be changed during the measurement;
e) Before the photoelectric performance test of the displays, all light-emitting diodes shall be lit at 30% of the highest luminance, with the preheating time not less than 15min.
4.2 Instruments and software for measurement
Unless otherwise specified, the performance of all instruments and apparatus for measurement shall meet the specific requirements for measurement:
a) color analyzer (similar instruments for measuring optical properties such as luminance and chromaticity may also be used);
b) light intensity meter;
c) illuminometer;
d) oscilloscope: with the width of frequency band not less than DC~100 MHz;
e) vernier caliper: with a division value of 0.02 mm;
d) feeler gauge: with a division value of 0.01 mm;
f) protractor: with a division value of 1°;
g) steel ruler: with a length of 1m;
h) vibration table: with an amplitude greater than 2 mm, a resonance frequency of 1 Hz~500 Hz, and vibration directions being vertical and horizontal;
i) thermometer;
j) photoelectric sensor: with a frequency response greater than 50 MHz;
k) test software: meeting the actual measurement requirements.
Note: The uncertainty of measuring equipment shall meet the technical requirements of relevant specifications and be verified as qualified. In the verification cycle, measurement shall be carried out according to the relevant operating procedures.
5 Measurement method
5.1 Mechanical property
5.1.1 Degree of protection provided by enclosure
It shall be measured according to the method given in GB 4208.
5.1.2 Assembly accuracy
5.1.2.1 Level up degree
5.1.2.1.1 Purpose
To measure the level up degree of LED displays assembly.
5.1.2.1.2 Measurement principle
See Figure 1 for the principle of concave measurement.
Figure 1
See Figure 2 for the principle of convex measurement.
Figure 2
5.1.2.1.3 Measurement conditions
Disconnect the display under measurement from the power supply, so that it is in black screen state.
5.1.2.1.4 Measurement steps
Measurement shall be carried out by following the steps below:
a) Place a 1 m long steel ruler at any position on the surface of the display;
b) For the measurement of concave, according to the method shown in Figure 1, the maximum gap, H, between the steel ruler and the surface of the displays shall be measured by the feeler gauge, which is the level up degree, P;
c) For the measurement of convex, according to the method shown in Figure 2, the maximum gap, H, between the steel ruler and the surface of the displays shall be measured by the feeler gauge, and the level up degree equals to H/2;
5.1.2.2 Relative deviation of pixel pitch
5.1.2.2.1 Purpose
To measure the center distance between any adjacent pixels, and calculate the relative deviation of the measured center distance from the nominal value using equation.
5.1.2.2.2 Measurement principle
See Figures 3 and 4 for the measurement principle for relative deviation of pixel pitch.
a) b)
Figure 3
5.1.2.2.3 Measurement conditions
Disconnect the display under measurement from the power supply, so that it is in black screen state.
5.1.2.2.4 Measurement steps
Measurement shall be carried out by following the steps below:
a) For a pixel composed of multiple LEDs, LEDs at the same position in two pixels shall be found out, and the pixel pitch shall be measured using a general measuring tool with a division value of 0.02mm according to the method shown in Figure 3;
b) For a pixel composed of a single LED, the pixel pitch shall be measured using a general measuring tool with a division value of 0.02mm according to the method shown in Figure 4;
Contents of SJ/T 11281-2017
Foreword i
1 Scope
2 Normative references
3 Terms, definitions and symbols
4 General requirements
5 Measurement method
5.1 Mechanical property
5.2 Optical properties
5.3 Electrical performance
Annex A (Normative) Slope of constant main wavelength line of standard light source E (equal-energy light source) in CIE 1931 chromaticity diagram
Annex B (Normative) Supporting test software
