There are two kinds of LED screen: graph-text screen and video screen, both of which are constituted by LED matrix blocks. Graph-text screen can display Chinese characters, letters and pictures synchronous with the computer. Video screen controlled by computer can not only display spot text and graph synchronously and vividly, but also can display two-dimensional, three-dimensional flash, video, TV program, VCD program and live broadcast.

Briefly speaking, LED screen is made up of two parts: main display body which is composed by several display units (display panel units or display cabinet units) that can be connected together and a set of controller (main control board or control system). Multifarious display panels (or cabinet units) with different specifications and controllers with different control technology can be constituted into various kinds of LED screens to satisfy different application environments with diverse requirements.

Classification of LED Screens:

1. According to using environments: Indoor LED screen and outdoor LED screen;

2. According to display colors: single base color LED screen, double base color LED screen and full color LED screen;

3. According to grey scale: 16, 32, 64, 128, 256 grey scale LED screen;

4. According to display performance: text screen, graph screen, synchronous video screen, TV video communication screen and market LED screen and so on.

The Structure of the Screen:

The following is an example of a complex synchronous video communication LED screen:

1. Metal Frame:

Inner frame of indoor screen is usually made up of Al alloy (angle Al or Al alloy tube) to carry the display panel and other circuit boards as well as switching power supply; the outer frame adopts brown Al alloy tube or stainless steels wrapped by Al alloy or a piece of sheet metal. The selection of outdoor screen frames is according to the size of screen and the bearing capability of the frame. Angle iron and I steal are commonly adopted. Al/Plastic board can be adopted to decorate the outer frame.

2. Display Unit

Display unit is the main body of the screen. It is made up of light-emitting materials and driving circuit. The display unit of indoor screen is unit display panel of various specifications; and that of outdoor screen is unit cabinet.

3. Host Controller

The function of the host controller is to cushion the input RGB digital video communication signals meanwhile to change the grey scale and reorganize them to generate all kinks of control signals.

4. Switching Power Supply

It is used to transform the 220V alternating current into all kinds of direct current to support various circuits.

5. Transmitting Cables

The display data and all kinds of controlling signals generated by the host controller are transmitted through twisted-pair cables to the screen.

6. Scanning Control Board

The function of it is to cushion the data, generate all kinds of scanning signals and duty cycle grey scale control signals.

7. Special Videocard and Multimedia Card

The special videocard of full color LED screen not only bear the basic functions of computer videocard, but can also output RGB digital signals and row, field and blanking signals to the host controller. Besides functions the same as the special videocard, multimedia card can also change the input simulated video signals into RGB digital signals (that is the collection of video communication).

8. Other information sources and external devices

Including computer, TV set, blue-ray disc, DVD, VCD, video camera and recorder and so on.