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Jul 13,2021| LED Knowledge
LED display is an unfamiliar field for new users. Below we enumerate common problems, hoping to help you
·What are the factors that consider the area of the LED display screen allowed by the user's site?
(1) The relationship between the effective viewing distance and the actual site size;
(2) Pixel size and resolution;
(3) Estimated area based on the unit board;
(4) Space for mechanical installation and maintenance of the screen body;
(5) The influence of the inclination of the screen on the distance.
·What are the playback effects that users need?
(1) Text display: it depends on its text size and resolution requirements;
(2) Ordinary video display: 512×384 pixels;
(3) Digital standard DVD display: ≥640×480 pixels;
(4) Complete computer video: ≥1024×768 pixels;
·What are the brightness requirements for the LED display?
The general brightness requirements are as follows:
(1) Indoor: >800CD/M2
(2) Semi-indoor: >2000CD/M2
(3) Outdoors (sit south and face north): >4000CD/M2
(4) Outdoors (sit north and face south): >6000CD/M2
·What are the brightness requirements of red, green and blue in terms of white composition?
Red, green, and blue contribute differently to the color of white. The fundamental reason is that the retina of human eyes feels differently for different wavelengths of light. After a large number of experimental tests, the following approximate proportions are obtained for reference design:
Simple red, green and blue brightness ratio: 3:6:1
The precise ratio of red, green and blue brightness is: 3.0:5.9:1.1
·Why use pure green tubes for high-end full-color displays?
In the actual production of LED display screens, three primary color LED tubes with high luminous efficiency and rich and bright colors should be selected, so that the area of the color triangle in the chromaticity diagram is as close as possible to the tongue-shaped spectrum color curve. In order to meet the rich colors and emit sufficient brightness, the tongue-shaped curve top is 515nm wavelength light, so high-end LED displays use pure green light LED tubes with a wavelength close to 515nm, such as 520nm, 525nm or 530nm wavelength light LED tubes. .
·How to calculate the brightness of a single tube under the condition of clear brightness and dot density requirements?
The calculation method is as follows: (take two red, one green, and one blue as an example)
Red LED light brightness: brightness (CD)/M2÷points/M2×0.3÷2
Green LED light brightness: brightness (CD)/M2÷points/M2×0.6
Blue LED light brightness: brightness (CD)/M2÷points/M2×0.1
For example: 2500 dot density per square meter, 2R1G1B, brightness requirement per square meter 5000 CD/M2, then:
The brightness of the red LED light is: 5000÷2500×0.3÷2=0.3
The brightness of the green LED light is: 5000÷2500×0.6÷2=1.2
The brightness of the blue LED light is: 5000÷2500×0.1=0.2
The brightness of each pixel is: 0.3×2+1.2+0.2=2.0 CD
·Why choose DVI display interface standard?
(1) DVI display card interface is a display interface that complies with computer international standards;
(2) It is easy to install without opening the case;
(3) High video memory, strong dynamic screen display ability;
(4) Strong software and hardware compatibility;
(5) Support all operating systems and application software, flexible and convenient display;
(6) Mass production, low cost and convenient maintenance.
·Can the LED display be controlled by a laptop, and why?
can. Recently, we have developed an Internet control center control system for Focus Media. The control center controls all outdoor advertising LED displays in different cities and regions. Of course, notebook control is not a problem.
·Except for the price, what are the differences between using Nichia tube and domestic tube for full-color LED display?
(1) Tube core: Nichia independently produces tube cores, and domestically produced tubes generally use American or Taiwanese company cores;
(2) Packaging: Nichia's independent packaging, there is no domestic production plant, and there are many domestic tube packaging manufacturers;
(3) Consistency: Nichia tubes have a small difference in wavelength of the same batch of tube cores, and the consistency is good, while the consistency of domestic tubes is relatively poor;
(4) Service life: Nichia pipes have a relatively long service life, and domestic pipes are attenuated seriously;
·What is the difference between indoor module full-color LED display and SMD full-color display?
(1) Light-emitting part: The display module of the module full-color screen is generally yellow-green, and the pure green module is more expensive; the SMD full-color screen generally uses a pure green tube core;
(2) Display effect: module full-color screen pixels have a thicker visual perception, lower brightness, and are prone to mosaic phenomena; SMD full-color screens have better consistency and higher brightness;
(3) Maintenance: The full-color module is not easy to maintain, and the replacement cost of the whole module is relatively high; the full-color patch is easy to maintain, and the single lamp can be repaired and replaced;
·Why is the production cycle of outdoor screens relatively long?
(1) Raw material procurement: The procurement cycle of LED tubes is longer, especially for imported dies, the order cycle takes 4-6 weeks;
(2) The production process is complicated: PCB design, cover production, glue filling, white balance adjustment, etc. are required;
(3) Strict structural requirements: generally box design, windproof, rainproof, lightning protection, etc. need to be considered.
·How to help users choose a suitable LED display?
(1) The need to display content;
(2) Confirmation of visual distance and viewing angle;
(3) Requirement of screen resolution;
(4) Requirements of the installation environment;
(5) Cost control;
·What is the general aspect ratio of LED display?
Graphic screen: Determined according to the displayed content;
Video screen: Generally 4:3 or close to 4:3; the ideal ratio is 16:9.
·The number of points that can be controlled by a control system?
Communication screen A card: single color, double color 1024×64
Communication screen B card: single color: 896×512 double color: 896×256
DVI two-color screen: 1280×768
DVI full color screen: 1920×1280
· LED display installation requirements?
Power supply requirements: the power supply connection point should be within the size of the screen
220V mains power supply, live wire 0 wire ground wire;
380V mains power supply, 3 live wires, 1 neutral wire, and 1 ground wire;
The cross-sectional area of the live wire and the neutral wire are the same;
The LED display above 10 kilowatts should be equipped with a step-down starting device.
Communication requirements: The communication distance is defined by the length of the communication line.
The communication cable should be installed according to the length of the communication cable used by the model of the installed LED display.
The communication line is forbidden to run in the same conduit as the power line.
Installation requirements: the display screen is installed horizontally on the left and right, and backward tilting is not allowed
Up and down adjustment rods should be installed for hoisting
Before wall-mounting, install forward tilting off hook
Add positioning support bolts for floor installation.
·What factors are generally considered in the size design of LED display?
When designing the screen size, there are three important factors:
(1) The need to display content;
(2) Space conditions of the site;
(3) Screen unit template size (indoor screen) or pixel size (outdoor screen).
·What are the power consumption indicators and power requirements of the LED display?
The power consumption of the LED display is divided into average power consumption and maximum power consumption. Average power consumption, also known as working power, is the actual power consumption in normal times. The maximum power consumption is the power consumption in extreme conditions such as startup or full lighting, and the maximum power consumption is an element that must be considered for AC power supply (wire diameter, switch, etc.). The average power consumption is generally 1/3 of the maximum power consumption.
The display screen is a large-scale precision electronic device. For safe use and reliable work, the AC220V power input terminal or the AC220V power input terminal of the computer connected to it must be grounded.
Note: The AC220V power input ground terminal of the computer has been connected to the computer case.
·What issues should be considered in the design and installation of outdoor screens?
The main problems of outdoor LED display are as follows:
(1) The LED display is installed outdoors, often exposed to the sun, rain, wind and dust, and the working environment is harsh. Electronic equipment being wet or severely damp can cause short circuit or even fire, cause failure or even fire, and cause loss;
(2) The display screen may be attacked by strong electricity and magnetism caused by lightning;
(3) The ambient temperature changes greatly. When the display screen is working, it will generate a certain amount of heat. If the ambient temperature is too high and the heat dissipation is poor, the integrated circuit may not work properly or even be burned, which will make the display system unable to work normally;
(4) The audience is wide, the viewing distance is long, and the field of view is wide; the ambient light changes greatly, especially if it is exposed to direct sunlight.
In response to the above special requirements, outdoor LED displays must:
(1) The junction between the LED screen body and the building must be strictly waterproof and leak-proof, and the screen body must have good drainage measures, and once the accumulation of water occurs, it can be discharged smoothly;
(2) Install lightning protection devices on the display screen and buildings, keep the LED display screen body and shell well grounded, and the grounding resistance is less than 3 ohms, so that the large current caused by lightning can be discharged in time;
(3) Install ventilation equipment to cool down so that the internal temperature of the screen is between -10°C and 40°C. Install an axial fan on the top of the back of the LED screen to dissipate heat;
(4) Use industrial-grade integrated circuit chips whose operating temperature is between -40°C and 60°C to prevent the display from starting up when the temperature is too low in winter.
(5) In order to ensure long-distance visibility under strong ambient light conditions, ultra-high-brightness light-emitting diodes must be selected;
(6) The display medium adopts a new type of wide viewing angle tube, which has a wide viewing angle, pure color, consistent coordination, and a life span of more than 100,000 hours. The outer packaging of the display medium is currently the most popular rectangular tube with a cover, sealed with silicone, and no metalized assembly; its appearance is exquisite and beautiful, sturdy and durable, and has protection from direct sunlight, dust, water, high temperature, and circuit short circuit. Features of "Five Preventions".