Comprehensive answers to common questions about LED display selection and application

What are the factors that consider the screen area that the user's site can allow?

(1) The relationship between effective sight distance and actual site size;

(2) Pixel size and resolution;

(3) unit-based area estimation;

(4) Screen mechanical installation and maintenance operation space;

(5) The influence of screen inclination angle on distance.

What playback effects do users need?

(1) Text display: depends on the text size and resolution required;

(2) Ordinary video display: 320×240 dot matrix;

(3) Digital standard DVD display: ≥640×480 dot matrix;

(4) Complete computer video: ≥800×600 pixels;

What are the brightness requirements of the screen based on the ambient brightness?

The general brightness requirements are as follows:

(1) Indoor: >800CD/M2

(2) Semi-indoor: >2000CD/M2

(3) Outdoor (facing south): >4000CD/M2

(4) Outdoor (facing north and south): >8000CD/M2

What are the brightness requirements for red, green and blue in white?

Red, green, and blue contribute differently to the color of white. The fundamental reason is that the retina of the human eye

The film has different perceptions of light of different wavelengths. After a lot of experimental tests, the following approximate ratios are obtained for reference design:

The simple red, green and blue brightness ratio is: 3:6:1

The precise red, green and blue brightness ratio is: 3.0:5.9:1.1

Why do high-end full-color displays use pure green tubes?

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 to make the color triangle area in the chromaticity diagram as close to the tongue-shaped color spectrum curve as possible to meet the requirements of rich colors and sufficient brightness. The top of the tongue-shaped curve is 515nm wavelength light, so high-end LED display screens 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 conditions of clear brightness and point density requirements?

The calculation method is as follows: (taking two reds, one green, and one blue as an example)

Red LED light brightness: Brightness (CD)/M2÷number of 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 dots per square meter, 2R1G1B, brightness requirement per square meter is 5000 CD/M2, then:

The brightness of the red LED 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) The DVI display card interface is a display interface that complies with international computer standards;

(2) It can be easily installed without opening the chassis;

(3) High video memory and strong dynamic image display capability;

(4) Strong software and hardware compatibility;

(5) Support all operating systems and application software, with flexible and convenient display;

(6) Mass production, low cost and easy maintenance.

Can the display be controlled by a laptop? Why?

No. The graphics card of the laptop is built-in and cannot be connected to the control system. Currently, BOE has a laptop with a DVI interface that can realize laptop control.

What are the differences between using Nichia tubes and domestic tubes for full-color screens, except for price?

(1) Die: Nichia produces its own die, while domestic tubes generally use die from American or Taiwanese companies;

(2) Packaging: Nichia Company independently packages, there is no domestic production factory, and there are many domestic tube packaging manufacturers;

(3) Consistency: The wavelengths of the same batch of Nichia tubes have little difference and good consistency, while the consistency of domestic tubes is relatively poor;

(4) Service life: Nichia tubes have a relatively long service life, while domestic tubes have a more serious attenuation;

What is the difference between indoor module full-color screen and SMD full-color screen?

(1) Luminous part: The display module of the full-color module screen is generally yellow-green, and the pure green module is more expensive; the full-color SMD screen generally uses a pure green tube core;

(2) Display effect: The pixel points of the module full-color screen have a rough visual feeling, low brightness, and are prone to mosaic phenomenon; the full-color screen of the patch has better consistency and higher brightness;

(3) Maintenance: Full-color modules are not easy to maintain, and the cost of replacing the entire module is high; full-color SMDs are easy to maintain, and single lamps can be repaired and replaced;

Can outdoor screens use SMD LEDs? Why?

No. The outdoor screen installation structure has strict requirements, and SMD LEDs cannot adapt to the harsh outdoor environment;

The brightness requirements for outdoor screens are relatively high, and currently SMD LEDs cannot meet the brightness requirements for outdoor screens.

Why is the production cycle of outdoor screens so long?

(1) Raw material procurement: The procurement cycle of LED lamps is relatively long, especially for imported tube cores, which require an order cycle of 4-6 weeks;

(2) The production process is complex: it requires PCB design, cover production, glue filling, white balance adjustment, etc.

(3) Strict structural requirements: Generally, it is a box design, and it is necessary to consider wind protection, rain protection, lightning protection, etc.

How to help users choose the right display?

(1) The need to display content;

(2) Confirmation of viewing distance and viewing angle;

(3) Screen resolution requirements;

(4) Installation environment requirements;

(5) Cost control;

What is the general aspect ratio of a 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.

How many points can a control system control?

Communication screen A card: monochrome, dual color 1024×64

Communication screen B card: monochrome: 896×512 dual color: 896×256

DVI dual color screen: 1280×768

DVI full color screen: 1024×512

What factors are generally considered in the size design of the display?

There are three important factors when designing the screen size:

(1) The need to display content;

(2) Site space conditions;

(3) Display unit template size (indoor screen) or pixel size (outdoor screen).

Display screens with a power of more than 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.

Install the communication cable according to the length standard of the display model to be installed.

Communication lines must not be routed in the same conduit as power lines.

Installation requirements: The display screen should be installed horizontally, and no backward tilt is allowed.

For hoisting, an upper and lower adjustment rod should be installed.

Install the forward tilting hook before wall mounting

For floor installation, positioning support bolts must be added.

What are the display power consumption indicators and power requirements?

The power consumption of the display screen is divided into average power consumption and maximum power consumption. Average power consumption is also called working power consumption, which is the actual power consumption in normal times. Maximum power consumption is the power consumption in extreme situations such as startup or full brightness. Maximum power consumption is a factor that must be considered for AC power supply (wire diameter, switch, etc.). 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 operation, its 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 is connected to the computer case.

What are the installation requirements for the display?

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, three live wires and one ground wire;

The cross-sectional area of ​​the live wire and the zero wire is the same;

Display screens with a power of more than 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.

Install the communication cable according to the length standard of the display model to be installed.

Communication lines must not be routed in the same conduit as power lines.

Installation requirements: The display screen should be installed horizontally, and no backward tilt is allowed.

For hoisting, an upper and lower adjustment rod should be installed.

Install the forward tilting hook before wall mounting

For floor installation, positioning support bolts must be added.

What issues should be considered in the design and installation of outdoor screens?

The main problems of outdoor screens are as follows:

(1) The display screen is installed outdoors, often exposed to the sun and rain, wind and dust, and the working environment is harsh. Electronic equipment that is wet or severely damp can cause short circuits or even fire, leading to failures or even fires, causing losses;

(2) The display screen may be attacked by strong electricity and strong magnetic fields caused by lightning;

(3) The ambient temperature varies greatly. The display screen will generate a certain amount of heat when it is working. If the ambient temperature is too high and the heat dissipation is poor, the integrated circuit may not work properly or even burn out, making the display system unable to work properly;

(4) The audience is wide, and the viewing distance and field of view are required to be long; the ambient light changes greatly, especially the possibility of being exposed to direct sunlight.

In view of the above special requirements, outdoor display screens must:

(1) The screen body and the joints between the screen body and the building must be strictly waterproof and leakproof; the screen body must have good drainage measures so that water can be discharged smoothly in case of accumulation;

(2) Install lightning protection devices on the display screen and buildings. The display screen body and shell should be well grounded, with a grounding resistance of less than 3 ohms, so that the large current caused by lightning can be discharged in time;

(3) Install ventilation equipment to cool down the screen so that the internal temperature is between -10℃ and 40℃. Install an axial fan on the back and top of the screen to discharge heat;

(4) Use industrial-grade integrated circuit chips with an operating temperature between -40℃ and 80℃ to prevent the display screen from failing to start due to low temperatures in winter. ;

(5) In order to ensure long-distance visibility under strong ambient light, ultra-high brightness light-emitting diodes must be used;

(6) The display medium uses a new wide-angle tube with a wide viewing angle, pure and consistent colors, and a service life of more than 100,000 hours. The outer package of the display medium is the most popular square cylinder with a shielding edge, silicone seal, and non-metallic assembly; its appearance is exquisite and beautiful, sturdy and durable, and has the "five protection" characteristics of anti-direct sunlight, dustproof, waterproof, high temperature, and circuit short circuit.