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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
发光二极管(LED)显示屏测试方法 1 范围 本标准规定了发光二极管(LED)显示屏的机械、光学、电学等主要技术性能参数的测试方法。 本标准适用于发光二极管(LED)显示屏(以下简称显示屏)的测试。 2 规范性引用文件 下列文件对于本文件的应用是必不可少的。凡是注日期的引用文件，仅注日期的版本适用于本文件。凡是不注日期的引用文件，其最新版本(包括所有的修改单)适用主本文件。 GB 4208 外壳防护等级(IP代码) SJ/T 11141—2017 发光二极管(LED)显示屏通用规范 CIE 1931 色度图 3 术语、定义和符号 SJ/T 11141—2017中确立的术语、定义和符号适用于本标准。 4 一般要求 4.1 试验条件 4.1.1 大气条件 除另有规定外，测试条件如下： a) 环境温度：15℃～35℃； b) 相对湿度：20％RH～80％RH； c) 大气压力:86 kPa～106 kPa。 4.1.2 仲裁试验的标准大气条件 除另有规定外，仲裁试验的标准大气条件如下： a) 环境温度：25℃±1℃； b) 相对湿度：48％RH～52％RH； c) 大气压力：86kPa～106kPa。 4.1.3 其他环境条件 除另有规定外，其他环境条件应按下列规定： a) 交流电源：(220±22)V、(50±1)Hz； b) 推荐计算机配置：主流计算机硬件配置，Windows操作系统，带有DVI输出的显卡； c) 测量环境应无影响测试准确度的机械振动、电磁和光电等干扰； d) 测试前将显示屏调试到最佳状态，测试过程中不得改变显示屏的配置参数和工作状态； e) 显示屏在进行光电性能测试前，应以最高亮度的30％点亮全部发光二极管，预热时间不少于15min。 4.2 测试仪表及软件 除另有规定外，所有测试仪器仪表性能应满足测试具体要求。 a) 彩色分析仪(用于测量亮度、色度等光学性能的同类仪器也可)； b) 光强仪； c) 照度计； d) 示波器：频带宽度不低于DC～100 MHz； e) 游标卡尺：分度值0.02 mm； d) 塞 规：分度值0.01 mm； f) 量角器：分度值1°； g) 钢 尺：长度1 m； h) 振动台：振幅大于2 mm，谐振频率1 Hz～500 Hz，振动方向垂直和水平； i) 温度计； j) 光电传感器：频率响应大于50 MHz； k) 测试软件应满足实际测量要求。 注：测量设备的不确定度应符合相关规范的技术要求并检定合格。在检定周期内，按有关操作规程进行测量。 5 测试方法 5.1 机械性能 5.1.1 外壳防护等级 按GB4208的规定方法进行。 5.1.2 拼装精度 5.1.2.1 平整度 5.1.2.1.1 目的 测量LED显示屏拼装的平整度。 5.1.2.1.2 测量原理 凹差测量原理见图1。
塞规放置处 钢尺 图1 凸差测量原理见图2。
塞规放置处 钢尺 图2 5.1.2.1.3 测量条件 被测显示屏断开电源，为黑屏状态。 5.1.2.1.4 测量步骤 按如下步骤进行测量： a) 将1 m长钢尽的侧面放置在显示屏屏面任意位置； b) 对于凹差的测量,按照图1的方法，用塞规测量钢尺侧面与显示屏屏面之间的最大空隙H即为平整度P； c) 对于凸差的测量，按照图2的方法，用塞规测量钢尺侧面与显示屏屏面之间的最大空隙H，平整度P＝H/2； 5.1.2.2 像素中心距相对偏差 5.1.2.2.1 目的 测量任意相邻像素之间的中心距，通过公式计算实测中心距和标称值的相对误差。 5.1.2.2.2 测量原理 像素中心距相对偏差的测量原理见图3和图4。
a) b) 像素间距 像素间距 图3 5.1.2.2.3 测量条件 被测显示屏断开电源，为黑屏状态。 5.1.2.2.4 测量步骤 按如下步骤进行测量： a) 对于多个LED组成的像素，找出两个像素中相同位置的LED，如图3方法用分度值为0.02mm的通用量具测量像素中心距； b) 对于单个LED组成的像素，如图4方法用分度值为0.02 mm的通用量具测量像素中心距；
