Analysis of the components and working principle of LED display

                                                  Analysis of the components and working principle of LED display

   

 The LED display is composed of a number of combinable splicing display units  to form the screen, plus a set of appropriate controllers. Therefore, a variety of specifications of display boards with different control technology controllers can form many kinds of LED displays to meet the needs of different environments and different display requirements.

 

一,The main composition of LED display 

   1. The metal structure frame is used to form an inner frame, which is equipped with various circuit boards such as display unit boards or modules and switching power supplies

   2. Display unit: It is the main part of the LED display, which is composed of LED lights and driving circuits. The indoor screen is the unit display board of various specifications, and the outdoor screen is the module box.

   3. Scanning control board: The function of the circuit board is data buffering, generating various scanning signals and duty cycle gray control signals.

   4. Switching power supply: convert 220V alternating current into various direct current and provide it to various circuits.

   5. Transmission cable: The display data and various control signals generated by the main controller are transmitted to the screen by twisted pair cables.

   6. Main controller: buffer, grayscale transformation, reorganization, and generate various control signals of the input RGB digital video signal.

   7. Special graphics card and multimedia card: In addition to the basic functions of computer graphics card, it also outputs digital RGB signals and line, field, blanking and other signals to the main controller at the same time. In addition to the above functions, multimedia can also convert the input analog video signal into a digital RGB signal.

 

二, Analysis of the main functional modules

   1. Video broadcast

Through multimedia video control technology and VGA synchronization technology, various forms of video information sources can be easily introduced into the computer network system, such as radio and television and satellite TV signals, camera video signals, computer animation information, etc., so the following functions can be realized:

Support VGA display, display a variety of computer information, graphics, images.

Support a variety of input methods; Support PAL, NTSC and other standards.

Real-time display of color video images for live broadcasting.

Relay of radio and television, satellite and cable television signals.

Real-time playback of video signals such as TVs, cameras, DVDs, etc.

It has the function of playing different ratios of pictures and text on the left and right at the same time

   2. Computer broadcasting

Graphic stunt display function: It has the functions of editing, zooming, flowing and animating the graphics and texts.

Display a variety of computer information, graphics, images, 2D and 3D computer animations and overlay text.

The broadcast system is equipped with multimedia software, which can flexibly input and broadcast a variety of information.

There are a variety of Chinese fonts and fonts to choose from, and English, Spain, French, German and other characters can also be entered.

There are a variety of playout methods, such as: single/multi-line pan, single/multi-line up/down, left/right pull, up/down, rotation, stepless zoom, etc.

Announcements, announcements, announcements and news are edited, and played instantly and in a variety of fonts to choose from.

   3. Network function

It is equipped with a standard network interface and can be connected to other standard networks.

Collect and broadcast real-time data of each database to achieve remote network control.

The Internet network can be accessed through the network system

It has a sound interface, which can be connected to audio equipment to achieve sound and pan synchronization.

   4. Screen control machine

The on-screen controller controls its corresponding display display. It can automatically run a continuous loop program to obtain relevant display data according to the given program list, or it can manually intervene to produce on-screen display effects. The pixels on the screen and the pixels on the corresponding area of the screen controller display – correspondence, direct mapping.

The screen controller can manually adjust the brightness of the display screen and select the grayscale nonlinear correction data suitable for the current environment, and the screen controller can also automatically adjust the display brightness and select different grayscale nonlinear correction data according to the ambient brightness through the network system.

The screen control machine can adjust the contrast and chromaticity of the image display. The screen controller transmits the information to be displayed to the video processing and control unit for video processing.

   5. Video processing and control unit

The video processing and control unit completes the image processing of the display data, which includes:

The second level of grayscale nonlinear correction can be adjusted automatically or manually.

Automatic or manual stepless brightness adjustment.

The grayscale control system can control the display to display 24-bit data with 8 bits for each primary color, that is, 256 levels of gray for each primary color.

Image noise reduction processing to ensure a cleaner and smoother image.

Image enhancement technology, image edge enhancement technology.

Motion compensation technology, chromaticity adjustment function.

   6. Visual processing

In the system, the brightness of each primary color of a single module can be adjusted separately, the color balance can be adjusted, and the mosaic phenomenon can be basically eliminated.

The video processing and control unit transmits the processed display information to the communication module for long-distance transmission to the display.

   7.A communication module

The communication module ensures that the display content of the screen controller is transmitted to the display over long distances without errors. The communication module encodes and decodes the transmitted information, and carries out long-distance transmission and receiving data processing. The communication module transmits the display information to the data distribution and scanning unit.

 

三,The main working principle of the display screen

The LED display is usually composed of the main controller, the scanning board, the display control unit and the LED display body, the main controller obtains the various color brightness data of each pixel of a screen from the computer display card, and then distributes it to a plurality of scanning plates, each scanning board is responsible for controlling a plurality of rows on the LED display screen, and the LED display signal on each row is transmitted in serial mode through the various display control units of the bank, and each display control unit is directly facing the LED display body. The work done by the main controller is to convert the computer display is the signal of the matching card into the data and control signal format required for the LED display. The display control function is similar to that of the image display, which is generally composed of a shift register latch with a grayscale control function. It's just that the scale of video LED displays tends to be larger, so integrated integrated circuits with a larger scale should be used. On the one hand, it accepts the video signal of the main controller, on the other hand, it transmits the data belonging to this level to its own display control unit, and at the same time, it also transmits the data that does not belong to this level to the next cascade of scanning wrench. The differences between the video signal and the LED display data in terms of space, time, sequence, etc., all need to be coordinated by a scanning board.