Basic knowledge of LED display

Basic knowledge of LED display:

1. What is LED? LED is the English abbreviation for Light Emitting Diode (Light emitting diode). The "LED" in the display industry refers to LEDs that can emit visible light.

2. What is a pixel? The small light-emitting pixels of the LED display have the same meaning as "pixels" in ordinary computer monitors.

3. What is the pixel pitch (dot pitch)? The distance from the center of one pixel to the center of another pixel.

4. What is the LED display unit module? It is a small unit composed of several display pixels, which is structurally independent and can constitute an LED display screen. Typical examples are "8 * 8", "8 * 16", "16 * 16", etc., which can be assembled into modules through specific circuits and structures.

5. What is DIP? DIP is the abbreviation of Double In-line Package, double in-line assembly.

6. What is SMT? What is SMD? SMT is Surface Mounted Technology (abbreviation of Surface Mounted Technology), which is a popular technology and process in the electronic assembly industry; SMD is Surface Mounted Device (abbreviation of Surface mounted device) .

7. What is an LED display module? The basic unit determined by the circuit and the installation structure, which has a display function and can realize the function of the display screen by simple assembly.

8. What is an LED display? Through a certain control method, a display screen composed of LED device arrays.

9. What is a lamp insertion module? What are the advantages and disadvantages? It means that the DIP-encapsulated lamp passes the lamp foot through the PCB board and fills the tin with solder in the lamp hole. The module made by this process is the plug-in lamp module; the advantages are large viewing angle, high brightness and good heat dissipation The disadvantage is that the pixel density is small.

10. What is a surface mount module? What are the advantages and disadvantages? The surface mount is also called SMT. The SMT packaged lamp is welded to the surface of the PCB board through a welding process. The lamp pin does not need to pass through the PCB board. The module made by this process is called a surface mount module; the advantages are: good display effect , The pixel density is large, suitable for indoor viewing; the disadvantage is that the brightness is not high enough, and the heat dissipation of the lamp itself is not good enough.

11. What is sub-surface stick module? What are the advantages and disadvantages? Sub-surface mount is a product between DIP and SMT. Its LED lamp has the same packaging surface as SMT, but its positive and negative level pins are the same as those of DIP. It is also soldered through the PCB during production. The advantages are: high brightness and good display effect. The disadvantages are: complex process and difficult maintenance.

12. What is 3-in-1? What are its advantages and disadvantages? Refers to the packaging of LED chips of three different colors of R, G, and B in the same gel; the advantages are: simple production, good display effect, and the disadvantages are: difficult to split the color, high cost; PLCC-4 SMD (3528, TOP) plastic leaded chip carrier PLCC (Plastic Leaded Chip Carrier).

13. What is 3 and 1? What are its advantages and disadvantages? The difference between CHIP SMD and PLCC SMD (3 in 1, 3 in 1) 3 in 1 means that the SMT lamps of three independent packages of R, G and B are vertically juxtaposed at a certain distance, so that not only has 3 in 1 Each of the advantages can also solve the various shortcomings of 3 in 1.

14. What is a dual primary color, pseudo color, full color display? Different display screens can be composed of light-emitting diodes of different colors. The dual primary color is composed of two colors of red, green or yellow-green, the pseudo color is composed of three different colors of red, yellow-green and blue, and the full color is composed of red , Pure green, pure blue three different colors.

16. What is the brightness level? The level of manual or automatic adjustment of the brightness of the whole screen from 1 low to high 1 brightness.

17. What is gray scale? Under the same brightness level, the technical processing level of the display from dark to bright.

18. What is 1 brightness? Under certain environmental illuminance, the basic color of Maipu Glossy LED display is at 1 large brightness and 1 large gray level.

19. What is PCB? PCB is (abbreviation of Printed Circuit Board) printed circuit board.

20. What is BOM? BOM is (abbreviation of Bill of material) bill of materials. 21. What is white balance? What is white balance adjustment? The white balance we mean refers to the white balance, that is, the balance of the brightness ratio of the three colors of R, G, and B; the adjustment of the brightness ratio and the white coordinates of the three colors of R, G, and B is called white balance adjustment . 22. What is contrast? Under a certain ambient illumination, the ratio of the large brightness of the LED display 1 to the background brightness.

23. What is color temperature? When the color of the light emitted by the light source is the same as that of the black body at a certain temperature, the temperature of the black body is called the color temperature of the light source. 24. What is the frame change frequency? The number of times that the information on the display screen is updated in a unit of time. 25. What is the refresh rate? The number of times the display screen is repeatedly displayed by the display.

26. What is a perspective? What is perspective? What is a suitable perspective? The viewing angle is the angle formed by the two observation directions and the normal direction of the same plane when the brightness of the observation direction drops to 1/2 of the brightness of the normal direction of the LED display screen. 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 angle of view is the angle formed by the direction in which the image content is clear and the normal line.

27. What is suitable for line-of-sight? It is the vertical distance of the position where the content on the display screen can be seen completely and without color shift, and the position where the image content is clear relative to the screen body.

28. What is a runaway point? How many kinds? Pixels whose luminous state does not meet the control requirements; out-of-control points are divided into: blind spots (also known as dead spots), constant bright spots (or dark spots), and flash points.

29. What is a 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, which requires a row control circuit; It can be clearly seen from the driver board: static drive does not require a line control circuit, and the cost is higher, but the display effect is good, the stability is good, the brightness loss is small, etc .; the scan drive requires a line control circuit, but the cost is low Poor display effect, poor stability, large loss of brightness, etc.

30. What is a constant current drive? What is a constant voltage drive? Constant current refers to the constant output current value specified in the driver IC's allowed working environment; constant voltage refers to the constant output voltage value specified in the driver IC's allowed working environment.

31. What is nonlinear correction? If the digital signal output by the computer without correction is displayed on the Maipu Glory LED display, color distortion will appear, so in the system control circuit, the original computer output signal is calculated by a non-linear function. Because of the non-linear relationship between the front and back signals, we often call it a non-linear correction;

32. What is the rated working voltage? What is the operating voltage? What is the supply voltage? Rated working voltage refers to the voltage when the appliance is working normally; working voltage refers to the voltage value of the appliance within the rated voltage range during normal operation; the supply voltage is divided into AC and DC supply voltages, and our display AC supply voltages are all It is AC220V ~ 240V, DC power supply voltage is 5V.

33. What is color distortion? Refers to the difference between the same object displayed in nature and on the display screen, and the sensory vision of the human eye.

34. What is a synchronous system and what is an asynchronous system? Synchronous and asynchronous are relative to the computer. The so-called synchronous system refers to the LED display control system that displays the content displayed on the display and the computer monitor. The asynchronous system is It means that the display data edited by the computer is stored in the display screen control system in advance, and the normal display of the LED display screen will not be affected after the computer is shut down. Such a control system is an asynchronous system.

35. What is the blind spot detection technology? Through the host computer software and the underlying hardware, the blind spots (LED open and short circuit) on the display can be detected, and a report is formed to tell the LED screen manager that such a technique is called blind spot detection technology.

36. What is power detection? Through the host computer software and the underlying hardware, the working conditions of each power supply on the display can be detected, and a report is formed to tell the LED screen manager that such a technology is called power detection technology.