As the market demand and the rapid progress of micro spacing LED display technology and mature, distance between micro-LED display pixel pitch is more and more small, now the market has launched P1.4, P1.2, P0.9 spacing LED display, and widely in the center of the video conference, command and control, monitoring, radio and television media in the fields of application. 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.
On the technical level, the smaller the pixel spacing of the micro-spacing display, the higher the requirements of the LED assembly, assembly, splicing process and structure. This paper will make a brief analysis of the technology of micro-spacing LED display so that users can better understand the micro-spacing LED products.
1. Packaging technology:
The display screen of the density of P2 is 1515, 2020 and 3528, and the shape of LED pin is either J or L. Side to weld tube foot, the weld area will have the reflection, the ink color effect is poor, will need to increase the mask to improve contrast. The density is further improved, and the encapsulation of L or J cannot meet the application requirements, and the QFN packaging method must be adopted. The characteristics of this process are no lateral welded tube foot, no reflection in the welding area, so that the color effect is very good. In addition, the overall black integration design is used to design molding, the contrast of the image is increased by 50%, and the display effect is better than the previous screen.
2. Printed circuit board technology:
With development trend of micro space display, 4 layers 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 cannot meet the requirements, the rapid development of laser drilling technology will meet the micro-hole machining.
3. Printing technology:
An excessive amount of solder paste and the offset of printing directly affect the welding quality of the lamp tube. The correct PCB design needs to be communicated with the manufacturer to realize the design. The opening size and the correct printing parameters are directly related to the amount of the printing paste. Generally, the 2020RGB device adopts the electric polishing laser steel mesh with a thickness of 0.1-0.12mm, and 1010RGB is recommended to use the steel mesh of 1.00-0.8 thickness. The thickness, opening size and the amount of tin are increasing. The quality of micro-spacing LED welding is closely related to the printing of solder paste, and the use of functional printing presses such as thickness detection and SPC analysis will play an important role in reliability.
4. Application technology:
The small deviation of each RGB device position will lead to uneven display, which will require higher precision of the mounting equipment.
5. Welding process:
Reflux welding temperature rise too fast will lead to wetting imbalance, which will lead to the deviation of the device in the process of wetting and imbalance. Excessive wind circulation can also cause the 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. The average pixel spacing is used as a control value of 2%.
6. Cabinet assembly:
The box body is a combination of different modules, and the overall effect of the box body is directly related to the opening of the box body. 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, we need to make a measurement to calculate the modular joint, and then use the metal film of relative thickness as the pre-insertion of the fixture.
7. Screen body assembly:
The finished box needs to be assembled to display the refined image, video. However, the size tolerance and assembly accumulation tolerance of the box can not be ignored. The pixel spacing of the most recent devices between the box and the box is too large and too small will result in a hidden line and a bright line. The problem of hidden lines and bright lines is the difficult problem that is not to be ignored and needs to be solved urgently. Some companies adjust the nuts with 3m tape and box to achieve the best results.
8. System card selection:
The distance between microdisplay lines and uniformity of light and shade, the 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 light and shade lines and uneven luminance and chrominance. The high-performance system card is used for the brightness and color correction of the micro-spacing LED display, so that the display can achieve good brightness and uniformity of color, and the display effect is better.
Meet customer displayed on precision, high efficiency and energy-saving, stable and reliable LED display products, the best quality micro spacing is the production requirement of micro distance between the LED manufacturer, only implement related raw materials and production technology of the control, micro spacing can bring higher-end users to show effect LED display.
