LED display quality control

Jul 13,2021| LED Knowledge

LED display quality control standard system:

1. Fan    Wai

This standard specifies the definition, classification, technical requirements, inspection methods, inspection rules, and storage requirements for marking, packaging, and transportation of LED displays. This standard applies to LED display products. It is the main technical basis for LED display product design, manufacturing, installation, use, quality inspection and the formulation of various technical standards and technical documents.

Second, use the standard

The provisions contained in the following standards constitute provisions of this standard through quotation in this standard. At the time of publication of the standard, the editions shown were valid. All standards will be revised, and all parties using this standard should explore the possibility of using the latest version of the following standards.

GB191-90    Packaging, storage and transportation pictorial mark

GB2423.1-89  Basic environmental test procedures for electrical and electronic products  Test A: Low temperature test method

GB2423.2-89  Basic environmental test procedures for electrical and electronic products  Test B: High temperature test method

GB2423.3-89 "Basic environmental test procedures for electrical and electronic products" Test Ca constant damp heat test method

GB4943-95    Information technology equipment (including electrical business equipment) safety

GB6388-86   Transportation packaging receipt and delivery mark

GB6587.4-86  Electronic measuring instrument vibration test

GB6587.6-86  Electronic measuring instrument transportation test

GB6593-86   Electronic measuring instrument quality inspection rules

GB9813-88     general technical conditions of micro digital electronic computer

GB11463-89   Reliability test of electronic measuring instrument

SJ/T10463-93  Requirements for packaging, marking and storage of electronic measuring instruments

3. Definition

This standard uses the following abbreviations and definitions:

3.1  LED light-emitting diode  ligth emitting diode the abbreviation of LED light-emitting diode

3.2 "LED display" "LED" panel" through a certain control method, used to display text, text, graphics, images, animation, market information and other information, as well as TV, video signals and a display screen composed of an array of LED devices.

3.3 "Display unit" "display" unit" is determined by the circuit and installation structure and has the display function to form the smallest unit of the LED display screen.

3.4 "Fatal unqualified" critical" defective" A disqualification that may cause hazards or unsafe conditions to the use and maintenance of the product or the personnel related thereto, or the important characteristics of the unit product do not meet the requirements or the quality characteristics of the unit product seriously do not meet the requirements.

3.5 Out-of-control point "out-of-control" point" light-emitting state does not match the display state required by the control and is a discrete LED basic light-emitting point.

3.6 Pseudo-color LED display pseudo-color LED panel LED display composed of single-color LED devices of different colors are installed in different areas of the LED display.

3.7 Full-color LED display all-color LED panel  is composed of red, green and blue three primary color LED devices and can be adjusted to a multi-color LED display.

Four, classification

LED displays can be classified according to the following conditions:

4.1 "Using environment" The LED display is divided into indoor LED display and outdoor LED display according to the use environment.

4.2 "Display color" The LED display screen is divided into single-color LED display (including pseudo-color LED display), dual-color LED display and full-color (three-color) LED display according to the display color. According to the gray scale, it can be divided into 16, 32, 64, 128, 256 gray scale LED display screens and so on.

4.3 "Display performance" LED displays are divided into text LED display, graphic LED display, computer video LED display, TV video LED display, and market LED display according to display performance. Market LED displays generally include LED displays for securities, interest rates, futures and other purposes.

4.4 In the basic luminous point non-market LED display, indoor LED display can be divided into Φ3mm, Φ375mm, Φ5mm, Φ8mm, and Φ10mm according to the LED single point diameter used; outdoor LED display according to the pixel diameter used Can be divided into Φ19mm, Φ22mm and Φmm26 LED display screens. According to the size of the digital tube used, the market information LED display can be divided into 114.99999999999999pxm (1.8inch), 145px (2.3inch), 190px (3inch) and other LED displays.

Five, requirements

5.1   Hardware usage environment of LED display

The hardware part of the LED display screen includes a general-purpose computer part, a communication line, a special data conversion part and a display part determined according to the type, area, and use site of the LED display. It should be stated in the detailed specification:

a. Requirements for the computer host, various optional plug-in cards, external equipment and communication interfaces;

b. Requirements for communication lines and indicate the maximum communication distance;

c. The communication method between the data conversion part and the host computer;

d. Power supply requirements and structural installation requirements.

5.2  The software environment of the LED display

The LED display screens with different performance should be equipped with display software that can meet their display function requirements. The software has the following functions:

a. Meet the requirements of serialization and standardization, and be able to

b. Use the operating system and language specified in the detailed specification;

c. Equipped with complete self-check procedures and various levels of diagnostic procedures as required;

d. Equipped with corresponding dedicated software for special-purpose LED displays.

5.3  structure and appearance

5.3.1  Structure-The LED display part can be made of steel, aluminum, wood and other materials. The structure is required to be strong and beautiful.

5.3.2   Appearance-LED display frame has no obvious scratches. The pixel tubes of the outdoor LED display should be installed uniformly, without loosening or breaking the tube shell.

5.4 Safety requirements, the LED display is a Class I safety equipment specified by GB4943.

5.4.1  LED display screen protective ground terminal.

5.4.2  safety mark

5.4.2.1 The protective grounding terminal of the LED display should be marked.

5.4.2.2 The LED display should have warning signs at the fuse and switching power supply.

5.4.3 Ground leakage current, the ground leakage current of the LED display should not exceed 3.5mA (AC effective value).

5.4.4  Dielectric strength, the LED display can be tested at 50HZ, 1500V (AC effective value) for 1min without insulation breakdown.

5.4.5 Temperature Rise When using the LED display, the temperature rise of the metal part after the thermal equilibrium is reached does not exceed 45K, and the temperature rise of the insulating material does not exceed 70K.

5.5 LED display performance characteristics

The text LED display screen and the graphic LED display screen shall have the moving in and out mode and display mode specified in the detailed specification.

Animation function--Requires that the LED display animation display is consistent with the display of the corresponding area of the computer monitor;

Text display function--requires stable text display and clear crosstalk;

Grayscale function-requires the level of grayscale specified in the detailed specification.

In addition to the functions of animation, text display, and grayscale, the TV video LED display should be able to show TV and video images. The quotation LED display has the corresponding quotation display capability.

5.6   Uniformity-the requirements for the uniformity of the LED display should be specified in the detailed specification.

5.7   Out-of-control point-the out-of-control point of the indoor LED display should not be more than three ten thousandths, and the out-of-control point of the outdoor LED display should not be less than three thousandths; and it is discrete.

5.8 Power supply--The power supply of the LED display is 220W±10%, 50HZ±5% or 80V±10%, 50HXZ±5%, the maximum power consumption per unit display area of various LED displays should be specified in the detailed specifications Or the total power consumption of the LED display.

5.9 Environmental adaptability

5.9.1 Temperature-The ambient temperature of the indoor screen is: working environment low temperature: 00C; high temperature: +400C. Storage environment: low temperature: -400C; high temperature: +600C. The ambient temperature of the outdoor screen is: working environment low temperature: optional -200C, -100C; high temperature: +500C. Storage environment: low temperature: -400C; high temperature: +600C.

5.9.2 Humidity and heat--At the highest operating temperature, the LED display should be able to work normally under the condition of a relative humidity of 90%.

5.9.3  Vibration-LED display screen withstands the vibration received during transportation, loading and unloading, and moving of cars, trains, airplanes, etc. The on-board screen should be able to work normally during the operation of the installed vehicle.

5.9.4  Transportation-The LED display can be transported by ordinary means of transportation such as cars, trains, and airplanes.

5.10 Reliability requirements, the MTBF (ml) of the LED display unit should not be less than 10000h.

Sixth,   check   test   Fang   method

6.1 "The hardware use environment of the LED display" Use visual inspection to check the hardware use environment of the LED display, and it should meet the requirements of 5.1.

6.2 "The software use environment of the LED display" Use visual inspection to check the software use environment of the LED display, and it should meet the requirements of 5.2.

6.3 "Structure and Appearance" Use visual inspection to check the structure and appearance of the LED display, and it should meet the requirements of 5.3.

6.4 Safety requirements

6.4.1  grounding-check the LED display by visual inspection, which should meet the requirements of 5.4.1.

6.4.2  Safety mark-Check the safety mark of the LED display screen by visual inspection, which should meet the requirements of 5.4.2.

6.4.3  Leakage current to ground--Under 1.1 times the rated power voltage, test the ground leakage current between the power cord of the LED display screen and the metal frame, and it should meet the requirements of 5.4.3.

6.4.4   Dielectric strength-the power switch of the LED display screen is in the on position, and 1500V (AC effective value) is applied between the power input terminal and the metal frame or the metal structure that can be touched for 1 min, which should meet the requirements of 5.4.4 Claim.

6.4.5 Temperature rise-After working for one hour, use a point thermometer to test the temperature of each touchable point on the LED display, which should meet the requirements of 5.4.5.

6.5   performance characteristics-according to the different types of LED display, check the performance characteristics of the LED display, should meet the requirements of 5.5. Use the display test software for the text and graphic LED display to check the moving in and out mode and the display mode by visual inspection. The computer video LED display screen is visually inspected, the computer animation is used to compare the animation function, the LED display screen and the computer monitor are used to check the text display function, and the special test software is used to check the grayscale function. In addition to the above-mentioned animation, text, and gray-scale function checks on the TV video LED display, there should also be a video source check TV and video recording function. For various market quotation LED display screens, the corresponding test software should be used to check the market quotation display function.

6.6   Uniformity—Check the uniformity of the LED display by visual inspection, and it should meet the requirements of 5.6.

6.7   Out of Control Point-Check the out of control point of the LED display by visual inspection, and it should meet the requirements of 5.7.

6.8   Power Supply-Use a wattmeter to measure the power supply of the LED display, and it should meet the requirements of 5.8.

6.9 Environmental adaptability

6.9.1   High temperature load test-The high temperature load test is carried out on the display unit according to the provisions of GB2423.2. The indoor screen is at (40±2) 0C, and the outdoor screen is energized for 8h at (50±2) 0C. , Check once an hour. Check the moving in and out mode, display mode, uniformity and out-of-control points of the text LED display and the graphic LED display. Check the animation function, text display function, gray function, uniformity and out of control of the computer video and TV video LED display. Point. Check the market display function on the market LED display. All should meet the requirements of 5.5, 6.6 and 5.7.

6.9.2   High temperature storage test-The high temperature storage test is carried out on the display unit according to the provisions of GB2423.2. Stored at (60 ± 2) 0C for 4 hours, and after 4 hours at room temperature, the text LED display Check the moving in/out mode, display mode, homogeneity and out-of-control points with the graphic LED display. Check the animation function, text display function, gray scale function, uniformity and out of control points on the computer video and TV video LED display. Check the market display function of the market LED display. All should meet the requirements of 5.5, 5.6 and 5.7.

6.9.3 ``Damp and heat load test-The damp and heat load test is carried out on the display unit according to the provisions of GB2423.3. The indoor screen is at (40±2) 0C, and the relative humidity is 87%  -93%. (50±2) 0C, 8H when the relative humidity is 87%-93%, and check it every hour. Check the moving in and out mode, display mode, uniformity and out-of-control points of the text LED display screen and the graphic LED display screen. Check the market function of the market LED display. All should meet the requirements of 5.5, 5.6 and 5.7.

6.9.4   Constant Humidity and Heat Test--The constant humidity and heat test is carried out on the display unit according to the provisions of GB2423.3. The indoor screen is at (40±2) 0C and the relative humidity is 87%-93%, and the outdoor screen is ( 50 ± 2) 0C, the relative humidity is 87%-93% under the conditions of storage 48H. After the storage test is over, the ground leakage current, dielectric strength and temperature rise shall be measured immediately, which shall meet the requirements of 5.4.3, 5.4.4, and 5.4.5. After returning to 4H at room temperature, check the moving in and out mode, display mode, uniformity and out-of-control points of the text LED display and the graphic LED display. Check the moving in and out mode and display mode of the computer video and TV video LED display. , Uniformity and out-of-control points are fixed. Check the animation function, text display function, grayscale function, uniformity and out-of-control points of the computer video and TV video LED display. Check the market display function of the market LED display. All should meet the requirements of 5.5, 5.6 and 5.7.

6.9.5   Vibration test-Vibration test BG6587.4 is performed on the display unit. Under the conditions of vibration frequency 5H-55H-5H and amplitude of 0.19MM, 5IMN scans once, two directions, and each direction scans twice .After the test, the text LED display and graphic LED


  Article KeyWords:

 

Get In Touch For More Information

JYLED Led Display Whatsapp Contact Number