With the demand of the economic market and the rapid progress and maturity of micro-spacing LED display technology, the point spacing of micro-spacing LED display is getting smaller and smaller. Now the market has launched P1.4, P1.2, P0.9 and other micro-spacing LED display, and is widely used in video conference, command and control, monitoring center, radio and television media and other fields.During the past few years, the distance between the LED display screen hd display, high refresh rate, seamless splicing, convenient and flexible in assembling and disassembling, good heat dissipation system, the characteristics of energy conservation and environmental protection industry has been the majority of the users, however, further, said to the small distance between the LED screen concrete technology, the general public has rarely known, "a man who knows one second", the lack of professional knowledge, directly LED to the emergence of the blind spot of choose and buy.
From the technical level, the smaller the pixel spacing of the micro-spacing display screen, the higher the requirements for LED mounting, assembly, splicing process and structure.In this paper, the micro-spacing LED display technology for a brief analysis, so that users more thorough understanding of micro-spacing LED products.
The display screen with density above P2 generally adopts lights of 1515, 2020 and 3528, and the shape of LED pin adopts J or L packaging.Side welding pin, welding area will have reflective, poor ink effect, it is necessary to increase the mask to improve the contrast.With the further increase of density, the encapsulation of L or J cannot meet the application requirements, so QFN encapsulation must be adopted.This process is characterized by no side welded pins, no reflective welding area, so that the color effect is very good.In addition, the all-black integrated design is used for molding. The contrast of the picture is improved by 50%, and the picture quality effect of the display application is better than that of the previous display screen.
2. PCB technology:
With development trend of micro space display, 4 layer and 6 layer board, printed circuit board using micro hole and buried hole design, printed circuit graphics fine wires, micro Kong Hua narrow spacing, used for the processing way of mechanical drilling technology can not meet the requirements, the rapid development of laser drilling technology will meet the micro hole machining.
3. Printing technology:
Too much or too little solder paste and printing offset directly affect the welding quality of microspacing display lamp tube.The correct PCB solder plate design should be implemented in the design after communication with the manufacturer. The size of the screen opening and the correct printing parameters are directly related to the amount of solder paste for printing.Generally, the 2020RGB devices use the electropolished laser steel mesh with a thickness of 0.1-0.12mm, while the devices below 1010RGB are recommended to use the steel mesh with a thickness of 1.0-0.8.The thickness, opening size and tin amount increase proportionally.Micro-spacing LED welding quality is closely related to solder paste printing, and the use of belt thickness detection, SPC analysis and other functional printing presses will play an important role in reliability.
4. Mounting technology:
The slight deviation of each RGB device position in the micro-spacing display screen will result in uneven display of the screen body, which is bound to require higher precision of the mounting device.
5. Welding process:
Too fast temperature rise of reflow soldering will lead to unbalance of wetting, which is bound to cause deviation of the device in the process of unbalance of wetting.Excessive wind circulation can also cause device displacement.Reflow soldering machines above 12 temperature zones should be selected as far as possible. Chain speed, temperature rise and circulating wind force should be taken as strict control items. In other words, soldering reliability needs should be met, and device displacement should be reduced or avoided to be controlled within the demand range as far as possible.Generally, 2% range of pixel spacing is used as the control value.
6. Box assembly:
The box body is assembled with different modules, and the flatness of the box body and the gap between modules are directly related to the overall effect of the box body after assembly.Aluminum plate processing box and cast aluminum box are widely used box types at present, and the flatness can reach within 10 wires. The stitching gap between modules is evaluated by the distance between the nearest pixel of the two modules.Before assembly, it is necessary to measure and calculate the assembly seam of the module, and then insert the metal pieces of relative thickness as the jigs for assembly.
7. Screen assembly:
The assembled box body needs to be assembled into a screen body before the refined screen and video can be displayed.However, the dimensional tolerance of the box itself and the cumulative tolerance of the assembly can not be ignored for the assembly effect of the micro-spacing display screen.Box and box between the nearest device pixel spacing is too large, too small will lead to display dark lines, bright lines.The problem of dark and bright lines is a problem that cannot be ignored and needs to be solved urgently.Some companies make adjustments by attaching 3m tape and cabinet nut for the best effect.
8. System card selection:
The light-dark lines and uniformity and color difference of micro-space display screen are the accumulated defects of LED device differences, IC current differences, circuit design layout differences, assembly differences, etc. Some system card companies can reduce the light-dark lines, brightness and color differences through software correction.High performance system card is selected to correct the brightness and chromaticity of micro-spacing LED display screen, so that the display screen can achieve better brightness and chromaticity uniformity and achieve better display effect.
"Hand in hand with jia qian, win-win vision", to meet the customer precision display, energy saving, stable and reliable, the ultimate quality of micro-spacing LED display products is micro-spacing LED manufacturers production requirements, only to achieve the relevant raw materials and production technology control, micro-spacing LED display can give users a higher end of the display effect.