Technology | The composition of LED display and the working principle of functional modules

The LED display screen is composed of several display units (unit display board or unit display box) that can be combined and spliced to form a screen body, plus a set of appropriate controllers (main control board or control system). Therefore, display panels (or unit boxes) of various specifications can be combined with controllers of different control technologies to form many kinds of LED displays to meet the needs of different environments and different display requirements.

The main components of the LED display

1. The metal structure frame, its function is to form the inner frame, 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 this circuit board is data buffering, generating various scanning signals and duty cycle gray scale control signals.

4. Switching power supply: convert 220V AC power into various DC power supplies for various circuits.

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

6. Main controller: buffer the input RGB digital video signal, transform grayscale, reorganize, and generate various control signals.

7. Special display card and multimedia card: In addition to the basic functions of a computer display card, it also outputs digital RGB signals and line, field, blanking and other signals to the main controller. In addition to the above functions, multimedia can also change the input analog Video signal into a digital RGB signal (that is, video acquisition).

8. Computer or other input devices

Main working principle

The LED display is usually composed of a main controller, a scanning board, a display control unit and an LED display body. The main controller obtains the brightness data of each color of each pixel on a screen from the computer display card, and then distributes it to several scanning boards. The board is responsible for controlling several rows (columns) on the LED display, and the LED display signals on each row (column) are cascaded and transmitted through each display control unit in this row in a serial manner, and each display control unit directly faces the LED display body.

The work of the main controller is to convert the signal of the computer display card into the data and control signal format required by the LED display. The function of the display control single operation is similar to that of the image display screen, and is generally composed of a shift register latch with a gray level control function. It's just that the scale of the video LED display is often larger, so an integrated circuit with a larger integration scale should be used.

The role played by the scanning switch is the so-called link between the previous and the next. On the one hand, it receives the video signal from the main controller; A cascaded scan panel transmission. The differences in space, time, sequence, etc. between video signals and LED display data require the assistance of scanning boards.