The most comprehensive explanation of LED display

Source: RUI JIN

2018-04-01 09:01:34



The most comprehensive explanation of LED display

      LED display industry people together, it is easy to talk to LED display products: how much the distance between points, how to refresh, how to use constant current drive ... ... if you do not understand, this chat, is not that the pressure is good Big?

      How to do it? Said the term of this thing, today, to share with you the most full explanation of the LED display term, let you switch from LED display white light in 2017 instantly understand the Emperor!

    (Warm reminder, there are more and more applications for English acronyms, and more and more kinds of ambiguities are being made. Remember to remember that you don't make jokes.)

1. What is LED?
     LED is the LIGHT EMITTING DIODE. The LED in the display industry specifically refers to the LED that can emit the visible band;

2. What is a pixel?
     The smallest luminous unit of the LED display has the same meaning as the pixel in the ordinary computer monitor;

3, what is the pixel pitch (point spacing)?
     The distance between the centers of two adjacent pixels, the smaller the distance, the shorter the visual distance. The person in the trade usually abbreviates P to indicate the distance between points;

4, what is the pixel density?
     Also known as lattice density, usually refers to the number of pixels per square meter of display;

5, what is the LED display module?
     A minimum unit consisting of a number of display pixels that is structurally independent and can constitute an LED display. Typical 8*8, 8*7, etc.

6. What is DIP?
     DIP is the abbreviation of DOUBLE IN-LINE PACKAGE, dual inline assembly;

7. What is SMT? What is SMD?
     SMT is the surface mount technology (abbreviation of SURFACE MOUNTED technology), is the most popular technology and process in the electronics assembly industry; SMD is a surface mount device (abbreviation of surface mounted device);

8, what is the LED display module?

     A basic unit that has a circuit and a mounting structure, has a display function, and can realize a display function through simple assembly;

9, what is the LED display?
    Through a certain control method, a display screen composed of LED device arrays;

10. What are the advantages and disadvantages of a plug-in lamp module?
     It refers to the DIP packaged lamp passing the lamp foot through the PCB board and filling the lamp hole with solder. The module made by this process is the plug lamp group. The advantages are: high brightness and good heat dissipation. The disadvantage is that Small pixel density;

11: What is a surface mount module? What are the advantages and disadvantages?
     The surface mount is also called SMT. The SMT packaged lamp is soldered to the surface of the PCB board through the soldering process. The lamp pins do not need to pass through the PCB board. The module made of this process is called the surface mount module. The advantages are: good display effect. High pixel density, suitable for indoor viewing: The disadvantage is that the brightness is not high enough, the lamp itself is not good enough for heat dissipation;

12. What is a sub-adhesive module? What are the advantages and disadvantages?
     Sub-SMT is a product between DIP and SMT. Its LED lamp has the same package surface as SMT, but its positive and negative pins are the same as those of DIP. It is also manufactured through PCB. The advantages are: high brightness and good display effect. The disadvantages are: complicated process and difficult maintenance;

13. What is 3 in one? What are its advantages and disadvantages?
     It means that the SMT lamps encapsulated by three different colors of LED chips of different colors are vertically aligned along a certain distance. This not only has all the advantages of 3-in-1, but also can solve various shortcomings of 3-in-1: the process is complicated and maintenance is difficult. ;

14, what is the three and one?
      RGB three independent packaged SMT lamps are vertically arranged side-by-side with a certain distance. This not only has the advantages of 3-in-1, but also solves the various shortcomings of 3-in-1;

15, what is a dual-color, pseudo-color, full-color display?
     Through different colors of light-emitting diodes can form a different display, dual-color is composed of red, green or yellow-green color, pseudo-color is composed of red, yellow-green, blue three different colors, full-color is from red , pure green, pure blue three different colors;

16, what is the brightness?
       The light intensity emitted by a LED display unit area is expressed in units of CD/square meter, which is simply the intensity of light emitted by a square meter display;

17, what is the brightness level?
       The level of manual or automatic adjustment of the brightness of the entire screen from the bottom to the maximum brightness;

18, what is the gray level?
       At the same brightness level, the number of technical processing levels from the darkest to the brightest display;

19, what is the maximum brightness?
      Under a certain ambient illumination, the primary colors of the LED display are at the maximum brightness and the maximum gray level;

20. What is Moire?
      When shooting a full-color LED display, some irregular water ripples appear on the LED display screen. These water ripples are called "Moore" in physics.

21, what is the PCB?
      PCB is the (printed circuit board abbreviation) printed circuit board;

22. What is a cell board specification?
      Refers to the size of the cell plate, usually expressed as a unit cell length times a wide expression, in millimeters. (48×244);

23, what is the resolution of the cell board?
      Refers to how many pixels a cell board has, usually expressed as the number of rows of cell plate pixels multiplied by the number of columns. (eg: 64×32);

24. What is BOM?
      BOM is a bill of materials (abbreviation of bill of material).

25, what is the white balance, what is the white balance adjustment?
      What we call white balance refers to the white balance, which is the balance of the brightness ratios of the three RGB colors; the RGB three-color brightness ratio and the adjustment of the white coordinates are called the white balance adjustment;

26: What is contrast?
      Under a certain ambient illumination, the ratio of the maximum brightness and the background brightness of the LED display;

27, what is the color temperature?
      When the color emitted by the light source is the same as the radiated color of the black body at a certain temperature, the temperature of the black body is called the color temperature of the light source;

28, what is the color difference?
      The LED display consists of three combinations of red, green, and blue to produce a variety of colors. However, these three colors are made of different materials. The viewing angle is different. The spectrum distribution of different LEDs is changed. These differences that can be observed are called It is color difference. When observing the LEDs through a certain angle, the color of the LED changes, and the ability of the human eye to judge the color of the real picture (such as a movie picture) is better than that of the observation computer.

 29. What is the frame change frequency?
      The number of updates of the display screen information per unit time;

30. What is the refresh rate?
      The number of times the display screen is repeatedly displayed in the display unit per unit time;

31: What is the perspective? What is the perspective? What is the best perspective?
      The viewing angle is when the brightness of the viewing direction drops to 1/2 of the brightness of the normal line of the LED display. The angle between the two observation directions and the normal direction of the same plane. It is divided into horizontal and vertical viewing angles; the viewing angle is the angle between the direction of the image content on the display screen and the normal of the display screen. The best viewing angle is the angle between the normal direction of the image content and the normal line.

32: What is the best line of sight?
      Is the ability to just completely see the contents of the display, and not flat, the image of the most clear position of the vertical distance relative to the screen body;

33: What is the out of control point? Several kinds?
      Pixels that do not correspond to the lighting state and control requirements are divided into three categories: blind spot (also known as dead point), and constantly bright spot (or dark spot) flash point;

34, what is the static drive:? What is a scan driver? What is the difference between the two?
      The "point-to-point" control from the output pin of the driver IC to the pixel is called static drive. The "point-to-column" control from the output pin of the driver IC to the pixel is called scan drive. He needs to control the circuit from: The driver board can be clearly seen: static drive does not need to control the circuit, the cost of teaching, but the display is good, good stability, brightness loss teaching small, etc.; scan drive it requires line control circuit, but the cost is low, display Poor results, loss of brightness, etc.;

35. What is constant current drive? What is a constant voltage drive?
      Constant current refers to the constant current output value specified in the allowable working environment of the driver IC: Constant voltage refers to the voltage value specified in the constant output design within the allowable operating environment of the driver IC.

36. What is the ratio of the length and width of the LED display?
      Graphic screen: Determined according to the content displayed; video screen: generally 4:3 or close to 4:3; ideal ratio is 16:9;

37, a control system can control the number of points?
      Communication screen A card: monochrome, two-color 1024 × 64; communication screen B card: monochrome: 896 × 512 two-color: 896 × 256; DVI dual-color screen: 1280 × 768; DVI full-color screen: 1024 × 512;

38. What is a nonlinear correction?
      If the digital signal output from the computer is displayed without correction on the LED display, color distortion may occur. Therefore, in the system control circuit, the signal output from the computer output signal after a nonlinear function is calculated by the display screen. Because the front and back signals are nonlinear, we often call it nonlinear correction.

39. What is the rated operating voltage? What is the operating voltage? What is the supply voltage?
      The rated working voltage refers to the voltage when the voltage is used normally; the working voltage refers to the voltage value of the electric appliance within the rated voltage range during normal operation: the supply voltage is divided into AC and tributary supply voltages, and our actual AC supply voltage is both AC220V---240V, DC supply voltage is generally 5V DC12V Solar power supply is generally 12V;

40. What is color distortion?
      Refers to the same object displayed in nature and on the display, the difference between the two for the human visual sense;

41. What is a synchronous system and what is an asynchronous system?
      Synchronous and asynchronous are relative to what the computer says. The so-called synchronous system refers to the LED display control system that displays the content displayed on the display screen in synchronization with the computer monitor. The asynchronous system refers to storing the computer-displayed display data in advance. In the display control system, the shutdown of the computer will not affect the normal display of the LED display. Such a control system is an asynchronous control system;

42, what is the blind spot detection technology?
      Through the upper software and the underlying hardware, the blind spot on the display (LED open circuit and short circuit) can be detected and a report can be formed to inform the LED screen administrator. Such a technology is called blind spot detection technology;

43, what is the power test?
      Through the upper software and the underlying hardware, the working conditions of each power supply on the display screen can be detected, and a report is formed to tell the LED screen body manager. Such a technology is called power supply detection technology;

44, what is the brightness test? What is brightness adjustment?
     Brightness in brightness detection refers to the brightness of the environment in which the LED display screen is located. Through the light sensor, the ambient brightness of the display screen is detected. This detection method is called brightness detection; the brightness in the brightness adjustment refers to the LED display screen. The brightness sent out, the detected data feedback to the LED display control system or control computer, and then adjust the brightness of the display according to this data, called brightness adjustment;

45. What is a real pixel? What is a virtual pixel? What are the virtual pixels? What is pixel sharing?
      The real pixel refers to the relationship between the number of physical pixels on the display screen and the actually displayed pixels. The actual number of points on the display screen can only show how many points of image information. The virtual pixel refers to the relationship between the physical pixel number of the display screen and 1:N (N=2, 4) of the actually displayed pixel points. The image pixels that can be displayed are 2 or 4 times more than the actual pixels of the display screen. Pixels can be divided into virtual modes according to their virtual modes: software virtual and hardware virtual: divided into 2 times virtual and 4 times virtual according to multiple relations, and divided into 1R1G1B virtual and 2R1G1B virtual according to the mode of row lights on a module;

46. What is remote control? Under what circumstances?
      The so-called remote is not necessarily a long distance. The remote control includes the main control end and the controlled end in a local area network, and the space distance is not far; and the main control end and the controlled end are in two kinds of distances within a relatively long distance. The customer request or according to the customer control position exceeds the optical fiber directly. Control distance, then use remote control;

47. What is fiber optic transmission? What is a cable transmission?
      Optical fiber transmission is the use of transparent glass fiber transmission to replace electrical signals with optical signals, and cable transmission is the use of metal wires for direct transmission of electrical signals.

48, under what circumstances with network cable? Under what circumstances with fiber?
      When the distance between the display screen and the control computer is less than 100 meters, the cable is used for transmission. When the distance between the two is less than 500 meters and greater than 100 meters, multimode optical fiber is used. When the distance is more than 500 meters, a single-mode optical fiber is used.

49. What is LAN control? What is Internet Control?
      In a local area network, a computer controls another computer or connects to other external devices. This control method is called local area network control. The main controller achieves the purpose of control through the IP address of the controller in the Internet network. It is called the Internet. control;

50. What is DVI? What is VGA?
      DVI is the abbreviation of Digital Video interface, namely digital video interface. It is now a universal digital video signal interface;

51. What is a digital signal? What is a digital circuit?
      The digital signal means that the amplitude of the signal amplitude is discrete, and the amplitude value is limited to two finite values of 0 and 1. The circuit for processing and controlling such a west signal is called a digital circuit;

52, what is the analog signal, what is the analog circuit?
       Analog signal means that the value of signal amplitude is continuous in time; the circuit that processes and controls this signal is called analog circuit;

53. What is a PCI slot?
      PCI slot is based on PCI local bus (PEDPHERD componen