1, Packaging technology:
Above P2 led display screen
generally uses SMD 1515, 2020, 3528 of the lamp, LED pin shape using J or L package. Side welding pin, welding area will be reflective, ink color effect is poor, it is necessary to increase the mask to improve contrast. The density further increases, the L or J's encapsulation cannot satisfy the application demand, must adopt the QFN package method. This process is characterized by no lateral welding pins, no reflective welding area, which makes the color rendering effect very good.
In addition, the whole black integrated design molding, the contrast of the picture increased by 50%, showing the effect of the application of the image contrast to the previous display better.
2, Mount Technology:
Fine pixel pitch LED display of the RGB device location of the small offset will result in the display of the screen is uneven, it is bound to require a higher precision mounting equipment.
3, Welding technology: Reflow soldering temperature rise too fast will lead to uneven wetting, it is bound to cause the device in the wetting imbalance in the process caused by migration. Too much wind cycle can also cause the displacement of devices. As far as possible to choose more than 12 reflow soldering machine, chain speed, temperature rise, cycle wind as a strict control project, that is, to meet the requirements of welding reliability, but also reduce or avoid the device shift, as far as possible to control the demand range.
Generally, the 2% range of pixel spacing is used as the control value.
4, Printed circuit board technology: With the development trend of fine pixel pitch LED display, the 4-layer, 6-layer Board is adopted, the printed circuit board will adopt micro-hole and buried hole design, printed circuit graphic wire thin, micro-porous narrow spacing, processing in the mechanical way drilling technology has been unable to meet the requirements,
The rapid development of laser drilling technology will meet the micro-hole processing.
5, printing technology:
Too much, too little solder paste volume and printing offset directly affect the small pixel pitch LED display
lamp welding quality. The correct PCB pad design needs to communicate with the manufacturers to implement the design, the screen plate opening size and the correct printing parameters are directly related to the amount of solder paste printing. General 2020RGB devices using 0.1-0.12mm thickness of the electric polishing Laser Steel Network, 1010RGB the following devices recommend the use of 1.0-0.8 thickness of the steel net. The thickness, opening size and the amount of tin increased.
Micro-spacing LED welding quality is closely related to solder paste printing, with thickness detection, SPC analysis and other functions of the printing presses will play an important role in reliability.
6, screen assembly:
Assembly of the finished box needs to be assembled into a screen to display the fine screen, video. However, the size tolerance and assembly accumulative tolerance of the box itself can not be neglected in the fine pixel pitch LED display assembling effect. The recent device pixel spacing between box and box is too large and too small will result in the display of dark lines, bright line. Dark lines, bright line problem is now fine pixel pitch LED display can not be ignored, the need to overcome the difficult problem.
Some of the companies through the Paste 3m tape, box micro adjustment nut Adjustment to achieve the best results.
7, Cabinet assembly:
The box is formed by splicing different modules, and the smoothness of the box and the gap between the modules are directly related to the overall effect of the box assembly. Aluminum plate processing box, cast aluminum box is the current application of a wide range of box types, flatness can reach 10 wire. The stitching gap between modules is evaluated by the nearest pixel spacing of the two modules, two pixels too close to the light line, two pixels too far can lead to dark lines.
Before assembling, it is necessary to measure and calculate the assembly seam, then use the relative thickness of the metal sheet as the fixture prior to the assembly.
8, System Card selection:
Fine pixel pitch LED display
light and dark line and uniformity, color difference is led device differences, IC current differences, circuit design layout differences, assembly differences, such as the accumulation of complaints, some system card companies through the software correction can reduce light and dark lines and brightness, chroma uneven. Select High-performance System Card, the micro-spacing LED display brightness, chroma correction, so that the display screen to achieve better brightness and chroma uniformity, achieved a better display effect.