The commonly used terms of the LED display to be known

LED Display:

LED screen (LED panel): LED is light emitting diode, the English abbreviation of the LED, referred to as LEDs. It is a display screen that controls the display of semiconductor light-emitting diodes to display text, graphics, images, animations, quotes, videos, video signals and other information.

LED display is divided into graphic display and video display, are composed of LED matrix blocks. Graphic display can be synchronized with the computer display of Chinese characters, English text and graphics; video display using microcomputer control, graphics, images and Mao, real-time, synchronous, clear information dissemination way to play a variety of information, but also display two-dimensional, three-dimensional animation, video, television, VCD programs and live. LED display screen bright color, three-dimensional sense of strong, static such as oil painting, moving as film, widely used in stations, terminals, airports, shopping malls, hospitals, hotels, banks, securities markets, construction market, auction houses, industrial enterprises and other public places.

Its advantages: high brightness, low operating voltage, small power consumption, miniaturization, easy to match with integrated circuits, drive simple, long life, impact resistance, stable performance.

Color

Put the red and green LEDs together as a pixel-made display called a two-color screen or a color screen; put red, green, and blue led tubes together as a pixel display called tri-color screen or full color.

Pixel

Production of indoor LED screen pixel size is generally 2-10 mm, often used to produce different colors of the LED tube core package into one. Outdoor LED screen pixel size is more than 12-26 mm, each pixel by a number of various monochrome LEDs, the common product is called the pixel tube. Two-color pixel tube is generally composed of 3 Red 2 green, three-color pixel tube with 2 red 1 green 1 blue composition. Whether using led to make monochrome, two-color or three-color screen, want to display the image needs to constitute a pixel of each LED's luminous brightness must be able to adjust, the fine degree of its adjustment is the gray level of the display. The higher the grayscale level, the more delicate the image is, the richer the color, and the more complex the display control system. General level 256 grayscale image, color transition has been very soft, and 16 levels of gray color image, color transition line is very obvious. Therefore, the color LED screen is now required to make 256 levels of grayscale.

Display speed

Refers to the speed of the LED display to update and convert the screen, usually expressed in frames per second.

Communication distance

General LED display signal input is a microcomputer or other equipment, the display from the signal input devices have a distance, so the need for LED display must support long-distance signal input and restore, basic all LED display support for more than 10 meters of signal input.

Life

Usually LED display is used outdoors, so the need for LED display can adapt to the outdoor changeable environment, in anti-aging and trouble-free operation than other display equipment to slightly better. Generally normal and trouble-free use time can reach more than 5,000 hours.

Interface

Interface is an important parameter indicator of all display devices, LED display as a display device is no exception, below we have a brief explanation of the common interface:

VGA input interface: The VGA interface uses the asymmetric distribution 15pin connection method, its working principle: is the video memory inside the digital format storage image (frame) signal in the RAMDAC to simulate the high frequency signal, then the output to the plasma imaging, so the VGA signal in the input terminal (LED display ), you do not have to go through the conversion of the matrix decoding circuit like other video signals. From the previous video imaging principle that VGA video transmission process is the shortest, so the VGA interface has many advantages, such as no crosstalk without circuit synthesis separation loss.

DVI Input Interface: DVI interface is mainly used to connect with the computer graphics with digital display output function, display the computer's RGB signal. The digital Visual Interface display interface, the digital display Working group abbreviation DDWG, was established by September 1998 at the Intel Developer Forum, The digital display interface standard is established.

DVI Digital terminal than the standard VGA terminal signal is better, the digital interface to ensure that all content in digital format transmission, to ensure that the host to monitor the transmission of data integrity (no interference signal introduction), you can get a clearer image.

Standard video input (RCA) interface: Also known as AV interface, usually is a pair of white audio interface and yellow video interface, it is usually used RCA (commonly known as Lotus Head) to connect, using only the standard AV cable with Lotus Head and the corresponding interface can be connected together. AV interface enables the separation of audio and video transmission, which avoids the loss of image quality due to audio/video mixing interference, but because the AV interface transmission is still a kind of brightness/chroma (Y/C) mixed video signal, still need to display device to light/color separation and chroma decoding to imaging, The process of first mixing and re-separating will inevitably cause the loss of color signal, and the chroma signal and luminance signal will have great opportunity to interfere with each other so as to affect the image quality of the final output. AV also has a certain vitality, but because of its own y/c mixing this insurmountable disadvantage can not be used in some pursuit of visual limits of the occasion.

S Video input: S-video specific English name is called separate video, in order to achieve better video effects, people began to explore a faster and better definition of video transmission, this is the current high-s-video (also known as two-component video interface), separate The meaning of video is to separate the video signal, that is, on the basis of the AV interface, the chroma signal C and luminance signal y are separated, and then transmitted separately with different channels, it appeared and developed in the late 90 's later in the last century, the standard 4-core (without sound) or expanded 7-core (including sound). Graphics and video devices with S-video interface (such as analog video capture/Edit card televisions and quasi-professional monitor TV cards/TV boxes and video projection devices, etc.) are now more prevalent, and since they are no longer y/c mixed transmission because of the AV interface, there is no need for color separation and decoding. and the use of separate transmission channels to a large extent to avoid the video device signal crosstalk caused by the image distortion, greatly improve the sharpness of the image, but the s-video still have two color difference signal (Cr Cb) mixed into a color signal C, transmission and then decoding in the display device as Cb and Cr Processing, so how much will still bring a certain signal loss of distortion (this distortion is very small but can still be found under strict broadcast-level video equipment testing), and because of the mixing of the CR Cb led to the color signal bandwidth also has a certain limit, so s-video although already relatively excellent but far from perfect, S-video is not the best, but it is also the most common video interface to use, taking into account current market conditions and other factors such as integrated costs.

Video chromatic aberration input interface: At present, some professional-grade video Workstation/Edit card professional-level video equipment or high-end DVD player and other home appliances see the YUV YCbCr y/b-y/b-y and other markings on the interface identification, although its marking method and the connector shape is different but refers to the same interface color difference port ( Also called component video interface). It usually uses the YPBPR and the YCBCR two kinds of identification, the former represents the progressive scan chromatic aberration output, the latter represents the interlaced chromatic aberration output. From the above relationship, we only need to know the value of y cr Cb can get G value (that is, the fourth equation is not necessary), so in the video output and color processing in the uniform ignore the green difference CG and only the Y CR CB, this is the basic definition of chromatic aberration output. As the s-video of the advanced product chromatic aberration output will s-video transmission of chroma signal C decomposition to chromatic aberration CR and CB, so that the two-way chromatic aberration mixed decoding and re-separation process, but also maintain the maximum bandwidth of the Chroma channel, Only need to go through the inverse matrix decoding circuit can be restored to RGB tricolor signal and imaging, which minimizes the video source to the video signal channel between the display imaging, to avoid the cumbersome transmission process caused by the image distortion, so the color output interface is the most current video output interface of the best one.

BNC port: Commonly used for workstations and coaxial cable connection connectors, standard professional video equipment input, output port. The BNC cable has 5 connector heads for receiving red, green, blue, horizontal and vertical sync signals. The BNC connector differs from the normal 15-pin D-Sub standard connector's special display interface. by R, G, b three primary color signal and line synchronization, field synchronization of five independent signal connectors. It is mainly used to connect workstations and other systems which require high scanning frequency. The BNC connector can isolate the video input signal, reduce the interference between the signals, and the signal bandwidth is larger than the ordinary D-Sub, which can achieve the best signal response effect.

RS232C serial port: RS-232C Standard (protocol) Full name is the EIA-RS-232C standard, where the EIA (Electronic Industry Association) on behalf of the American Electronics Industry Association, RS (ecommeded) Representative recommendation criteria, 232 is the identification number, C represents the latest modification of RS232 (1969), before this, there are rs232b, rs232a. It provides for connection of cables and mechanical, electrical characteristics, signal functions and transmission processes. The common physical standard also has eia& #0; Rs-232-c, eia& #0; Rs-422-a, eia& #0; rs-423a, eia& #0; RS-485. Only the eia& #0 is introduced here; Rs-232-c (abbreviated as 232,RS232). Computer input and output interface, is the most common serial interface, RS-232C standard interface has 25 lines, 4 data lines, 11 control lines, 3 timing lines, 7 spare and undefined lines, commonly used only 9, often used in conjunction with the 25-pin D-Sub Port, Its maximum transfer rate is 20kbps and the cable length is 15 meters. The rs232c port is used to control the computer signal input to the LED display.

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The commonly used terms of the LED display to be known