What is the working principle of the electronic display screen?

　　The electronic display screen (LCD) is what we commonly call a liquid crystal display. LCDs are not only suitable for monitors but can also be seen in products such as electronic watches, portable devices, and PDAs. Electronic display screens can be divided into Twisted Nematic (TN-LCD), Super Twisted Nematic (STN-LCD), Thin Film Transistor (TFT-LCD), etc. Currently, laptop and most desktop LCD screens are TFT-LCDs, which are used as liquid crystal screens. Just as the main component of a CRT is the cathode ray tube, the main component of an LCD is the LCD panel.

　　The liquid crystal screen contains two layers of sodium-free glass material with a layer of liquid crystal sandwiched in between. When a light beam passes through this liquid crystal layer, the liquid crystals twist side by side or irregularly, so the liquid crystal screen acts like a gate. It can control whether light can pass through or not.

　　The working principle of a CRT is based on an electron gun composed of a filament, cathode, and control grid. When powered, the filament heats up, stimulating the cathode to release an electron stream. The electron stream is accelerated by an internal metal layer with high voltage, passes through lenses to form a very fine electron beam, and hits the phosphor, causing it to emit light. The electron beam is deflected by the magnetic field generated by deflection coils, which can control the beam to point to a specified position on the screen. When the electron beam hits the screen, it forms a luminous spot, and several luminous spots can form an image.

　　RGB tri-color phosphor dots, when hit by electron beams of different intensities, can produce various colors. By controlling the strength and endpoints of the electron beam, various brilliant images are formed. Ordinary shadow mask CRTs have a mesh-like screen inside that looks like a sieve. The electron beam passes through the mesh and hits phosphor dots arranged in triangles. Three electron guns correspond to the RGB colors, hence called "three guns and three beams."

　　What is the configuration of the electronic display screen?

　　1. Electronic display screen metal structural frame

　　Indoor screens usually have an internal frame made of aluminum alloy (angle aluminum or aluminum square tube), with various circuit boards such as display boards and switching power supplies. The external frame is made of brown aluminum square tubes or aluminum shells, stainless steel, or sheet metal integrated. Outdoor screen frames are usually made of angle steel or I-beam steel, and the outline can be decorated with aluminum-plastic panels depending on the screen size and load capacity.

　　2. Display unit

　　The main part of the display screen, composed of luminous materials and driving circuits. Indoor screens are unit display boards of various specifications, while outdoor screens are unit boxes.

　　3. Scan control board

　　The function of the circuit board is to generate various scan signals and data buffers for duty cycle grayscale control signals.

　　4. Electronic display screen power on/off

　　Converts 220V AC into multiple DC voltages to supply various circuits. Folded twisted pair transmission cables carry display data and various control signals generated by the master from the twisted pair cable to the screen.

　　5. Main controller

　　Inputs RGB digital video signal buffering, grayscale conversion, reconstruction, and generates various control signals.

　　6. Electronic display screen dedicated

　　In addition to the basic functions of a computer graphics card, it also outputs digital RGB signals and signals such as line length and clear to the main output. Multimedia, besides these functions, can also convert input analog video signals into digital RGB signals (video capture).