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eight aspects for Ultra HD LED display Production process

2016-03-01 Technical support
With the development of science and technology, Ultra HD LED display technology continues to progress, now the indoor screen dot spacing is more and more popular with the market, some LED display manufacturers have now launched P1.4, P1.2 high-density LED display, and began to application in the field of command and control and video monitoring.
 
In the indoor monitor screen market DLP splicing and LCD splicing of these two kinds of display technology occupy the market opportunities, although they have their own advantages, but there are common a problem, that is the flat-fell seam between the display unit.High-density LED display has the congenital advantage can realize seamless splicing.High density display pixels smaller and smaller, more and more high resolution, according to the picture clearer, fine.When high-definition images of the standard, can fully meet the requirements of resolution.If high-density tubes are cheaper, it is bound to high-density LED display will have a larger market in the field of indoor video monitoring.
 
High-density LED display have hd display, high refresh rate, seamless splicing, convenient and flexible in assembling and disassembling, good heat dissipation system, etc.With pixel pitch smaller and smaller, the leds SMT, assembly, splicing process and structure request higher and higher.In this paper, the discussion about some process problems.
 
High-density LED display have hd display, high refresh rate, seamless splicing, convenient and flexible in assembling and disassembling, good heat dissipation system, etc.With pixel pitch smaller and smaller, the leds SMT, assembly, splicing process and structure request higher and higher.In this paper, the discussion about some process problems.
 
More than 1, LED options: P2 density display with 1515, 2020, 3528, lamp, LED tube feet J or encapsulation mode L shape.Lateral welding pin, welding area will be reflective, inky effect is poor, would need to increase the mask to improve contrast.Further improve the density, L or J encapsulation can't meet the demand of minimum electrical spacing, QFN packages must be used.
 
Unique original QFN packages welding process, this process is characterized by no lateral welded tube feet, welding area without a glance, so as to make the color effect is very good.Also use all black with integrated design mould, contrast ratio increased by 50%, according to application effect compared to previous screen quality better.
 
2, printed circuit board technology choices: with high density trend, 4 layer and 6 layer board, printed circuit board using micro hole and the 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.Rapid development of laser drilling technology will meet the micro hole machining.
 
3, printing technology: too little, too much of the amount of solder paste and offset printing directly affects the welding quality of high density display tubes.Right after the PCB pad design needs to communicate with factory to design frawl door opening size and printing parameters are correct or not directly related to the amount of solder paste printing.General 2020 RGB devices with 0.1 0.12 MM thickness of electrolytic polishing laser steel net, the thickness of 1.0 to 0.8 below 1010 RGB devices recommended stencil.Increasing thickness, opening size proportional to the amount of tin.High-density LED welding quality is closely related to solder paste printing, to detect the thickness of the belt, the SPC analysis functions such as the use of the printer will be important for reliability.
 
4, SMT technology: high density displays all the nuances of the RGB components position deviation will result in uneven screen display, certainly will require SMT equipment has higher accuracy, panasonic NPM equipment placement accuracy (QFN + / - 0.03 mm) will meet the P1.0 pasted on these requirements.
 
5, welding technology, reflow soldering temperature rise too fast will lead to wetting is not balanced, will inevitably lead to device in the process of wetting balance offset.Too much wind circulation can cause displacement of the device.Try to select more than 12 zones reflow welding machine, chain as well as wind speed, temperature, cycle as a strict control project, namely to meet the demand of welding reliability, and to reduce or avoid the shift of the device, as far as possible within the scope of control to the requirements.With 2% of the pixel pitch range commonly as the control values.
 
6, the box body assembly: the box body has different modules patchwork, the flatness and the module of the box body the gaps between the overall effect of the direct relationship between the housing assembly.Aluminum processing box, aluminum box is now widely used type of enclosure, can achieve 10 silk smoothness. Splicing gap between modules with two module to evaluate recently pixel spacing, too close to two pixel light is bright line, after two pixels far would result in a darker skin.Before assembling measure need to calculate the mold spellers seam, and then selects the relative thickness of the sheet metal as assembling fixture insert in advance.
 
7, the screen body assembly: assembly completed housing need ChengBing body assembly can be displayed only after fine pictures and video.But the case itself size tolerance and the assembling cumulative tolerance to high density effect of the display assembly have nots allow to ignore.Between casing and casing in recent device pixel spacing is too large, starts to show dark lines, bright line.Dark lines, bright line problem is high density screen now nots allow to ignore to attack the problem, need to wait.Part of the company through the paste 3 m tape, subtle body adjusting nut to adjust, in order to achieve the best effect.
 
8, the system card options: high density screen lines and uniformity of light and shade, color difference is LED device, IC current differences, circuit design, layout, assembly differences such as the accumulation of criticism, some system card companies through software modification can reduce the shade lines and uneven luminance and chrominance.Nova launch luminance and chrominance correction system has been applied to the high density display, and achieved a good display effect.
 
Conclusion: high density displays are fine display effect, must from the material selection, circuit design, temperature control, process, and other aspects.Believe that the high density screen with the progress of technology, the price of public, will be more and broader market share.