Angel Dehaven

In recent years, the characteristics of high-definition display, high refresh rate, seamless splicing, good heat dissipation system, convenient and flexible disassembly and assembly, energy saving and environmental protection of small-pitch LED display screens have been well known by the majority of industry users, but, going further, when it comes to small The specific process technology of pitch LED screens is rarely known to the general public, "only knowing one but not the other". The lack of professional knowledge directly leads to the emergence of blind spots in purchasing. From a technical point of view, the smaller the pixel pitch of a small-pitch display, the higher the requirements for the LED mounting, assembly, splicing process and structure. This article will analyze the various process technologies of small-pitch LED display screens, so that users can have a more thorough understanding of small-pitch LED products. Packaging Technology: Display screens with a density above P2 generally use 1515, 2020, 3528 lights, and the LED pin shape adopts J or L packaging. If the pin is welded sideways, the welding area will reflect light, and the ink color effect will be poor. It is necessary to add a mask to improve the contrast. If the density is further increased, the L or J package cannot meet the application requirements, and the QFN package must be used. The feature of this process is that there are no lateral welding pins, and there is no reflection in the welding area, which makes the color rendering effect very good. In addition, the all-black integrated design is used for compression molding, and the contrast ratio of the screen is increased by 50%, and the image quality of the display application is better than that of the previous display. Printed circuit board process: With the trend of high density, 4-layer and 6-layer boards are adopted, printed circuit boards will adopt micro-via and buried hole design, printed circuit pattern wires are fine, micro-holes are narrowed, and mechanical drilling used in processing Hole technology can no longer meet the requirements. The rapid development of laser drilling technology will meet the processing of micro holes. Printing Technology: Too much or too little amount of solder paste and printing offset directly affect the welding quality of high-density display lamps. The correct PCB pad design needs to be implemented in the design after communicating with the manufacturer. Whether the opening size of the stencil and the printing parameters are correct or not is directly related to the amount of solder paste printed. Generally, 2020RGB devices use an electropolished laser steel mesh with a thickness of 0.1-0.12mm, and devices below 1010RGB are recommended to use a steel mesh with a thickness of 1.0-0.8. Thickness, opening size increases proportionally to tin amount. The quality of high-density LED soldering is closely related to solder paste printing, and the use of printing machines with functions such as thickness detection and SPC analysis will play an important role in reliability. Mounting technology: The slight deviation of the position of each RGB device of the high-density display will lead to uneven display of the screen, which will inevitably require higher precision of the placement equipment. Welding process: Excessive temperature rise in reflow soldering will lead to uneven wetting, which will inevitably lead to device offset during the process of wetting imbalance. Excessive wind circulation can also cause device displacement. Try to choose a reflow soldering machine with a temperature zone above 12, chain speed, temperature rise, circulating wind, etc. as strict control items, that is, to meet the welding reliability requirements, and to reduce or avoid device displacement, and try to control it within the required range. Generally, video wall solutions the range of 2% of the pixel pitch is used as the control value. Box assembly: The box body is spliced by different modules, and the flatness of the box body and the gap between the modules directly affect the overall effect of the box body after assembly. Aluminum plate processing boxes and cast aluminum boxes are widely used box types at present, and the flatness can reach within 10 wires. The splicing gap between modules is evaluated by the distance between the nearest pixels of the two modules. If the two pixels are too close to each other, they will be bright Lines, two pixels too far will result in dark lines. Before assembling, it is necessary to measure and calculate the seam of the module, and then select a metal sheet of relative thickness as a jig and insert it in advance for assembly. Screen assembly: The assembled cabinet needs to be assembled into a screen before it can display refined pictures and videos. However, the dimensional tolerance of the cabinet itself and the cumulative tolerance of assembly cannot be ignored for the assembly effect of high-density display screens. If the pixel pitch of the nearest device between the cabinets is too large or too small, dark lines and bright lines will be displayed. The problem of dark lines and bright lines is a problem that cannot be ignored in high-density display screens and needs to be solved urgently. Some companies make adjustments by pasting 3m adhesive tape and finely adjusting nuts on the cabinet to achieve the best results. System card selection: Bright and dark lines and uniformity and color difference of high-density display screens are the accumulated criticisms of LED device differences, IC current differences, circuit design layout differences, and assembly differences. Some system card companies can reduce bright and dark lines and brightness and chromaticity differences through software correction. all. The brightness and chromaticity correction system launched by Nova has been applied to various high-density display screens and achieved good display effects.

The application of architectural glass in modern buildings is increasing, with more and more varieties and more complete functions. The application amount, application type and function of glass curtain wall in buildings can be used as a sign to evaluate the modernization degree of buildings. In particular, the decorative performance of LED display screens on architectural glass curtain walls can be said to be ever-changing. Without architectural glass, there will be no modern buildings. So what advantages does the glass curtain wall LED display have in the building lighting project? 1. High transparency, high light transmittance The transmittance of the Aureida glass curtain wall led display (also known as "transparent led display") can reach 65%-90%, and the thickness of each LED light strip is only 2mm, and the gaps between the light strips form a transparent effect . It is generally installed on the inside of the glass curtain wall of a commercial building, and the outdoor display is installed indoors, which completely breaks the limitations of the application of traditional LED displays on glass. 2. Simple structure and light weight The glass curtain wall LED display adopts a hollow strip design. Compared with the traditional LED display box, its structure is more flexible. The size of the box can be customized in combination with the specific size of the glass to better fit the glass curtain wall and reduce the load. pressure. Taking the Aureida P16 glass curtain wall LED display as an example, the weight per square meter is only 10KG, which is one-fifth of the weight of a normal outdoor LED display box, and is very popular among lighting engineering customers. 3. Quick installation and easy maintenance The structure of the glass curtain wall led display is relatively flexible, light in weight, and quick to install. The Aureida glass curtain wall LED display adopts the front maintenance method. When a certain LED light bar is damaged, only a single light bar needs to be replaced without replacing the entire module. The maintenance is completed indoors, with high efficiency and low cost. 4. Green and energy-saving, good heat dissipation performance Due to its high transparency, no noise, low power consumption and other good performances, the glass curtain wall LED display does not need any auxiliary heat dissipation equipment, and can let the wind force it to dissipate heat naturally. When it plays video advertisements, the part of the playing content displays light, and the rest does not. It saves energy by more than 30% than conventional LED displays. This playback method can also reduce energy consumption and light pollution, which responds to the national energy conservation and emission reduction. call. Glass curtain wall pixel led video wall display screens are generally installed in commercial buildings, shopping centers, banks, shopping malls, commercial streets, chain stores, hotels, municipal public buildings, landmark buildings and other scenes. It has both the practicality of led display screens and certain aesthetics and concealment. Glass curtain wall LED display is a high-end building lighting product, which plays an irreplaceable role in modern urban building lighting projects.

Glass curtain wall is a modern and fashionable architectural decoration, which adorns the city and makes the city more beautiful. The glass curtain wall LED display used with the glass curtain wall is even more sought after by the market. Its high transparency, invisible installation, green and energy-saving excellent performance make it stand out from many display products. So, how to make the glass curtain wall LED display achieve a better display effect? First, standardize the glass design. Glass is an important carrier for the installation of transparent LED display screens, and its size and shape directly affect the display effect of glass curtain wall LED display screens. When installing display screens with irregular and odd-shaped glass, not only the screen body needs to be customized, but also the cost is high; when designing the glass curtain walls of shops and buildings, owners should try to use glass with uniform size and reduce the use of special shapes , This can reduce the difficulty of installing the LED display screen on the glass curtain wall, reduce the keel, further improve the permeability, and make the screen display more transparent and beautiful. Second, choose the appropriate sharpness. Clarity is the resolution referred to in the industry, and it is also the loading point of the LED display. The clarity of the glass curtain wall LED display is mainly affected by its screen area and pixel spacing. The larger the screen area, the smaller the pixel spacing, and the higher the clarity. Owners can choose the appropriate definition according to the actual audience range and viewing distance of the advertisement to achieve economical and applicable effects. Again, brightness adjustment. Although the glass curtain wall LED display screen broadcasts advertising information to the outside world, it is essentially a type of indoor LED display screen and is installed in an indoor environment. Because outdoor led video screen advertisements require high brightness during the day, and low brightness is required at night, brightness adjustment is very necessary at this time. The conventional glass curtain wall LED display also uses a light-sensing probe and cooperates with related software to adjust the brightness, so as to ensure the comfort of tourists watching the screen, and then generate interest in the product and increase sales. In fact, there are still many ways to make the glass curtain wall LED display achieve better display effects. In life, everyone can pay more attention to store decoration and advertising effects, and make reasonable adjustments to achieve greater economic benefits.

A qualified small-pitch LED display that can stand the test must have undergone strict relevant tests before leaving the factory. Only in this way, after it is officially delivered to customers, can it guarantee a long period of normal operation and good display effect, and reduce the failure rate. Let's take a look at the evaluation standards and methods of government purchasers for small-pitch led screen (click to investigate) LED displays 1. Test methods and conditions for small-pitch LED displays (1) Equipment: 1 Blu-ray high-definition player with 1080P (1920×1080 full frame) resolution; 1 high-performance computer with 1080P HDMI output; 1 video signal splitter with 1-to-4 component component output. (2) Standard video sources, pictures, etc. for testing: blue light source disk; professional test video Hi-Definition Reference (select multiple scenes); DisplayX, SJ/T 11281-2007 "Light Emitting Diode (LED) Display Screen Test Method" standard Test software; computer-generated 1080P standard color scale, full-color gradient, gray scale and pictures from the Internet, pictures intercepted or generated by the above two items, etc., night scene pictures of highway bridges. (3) Test method: Before the official evaluation, each manufacturer is allowed to conduct on-site debugging for its own LED\large screen (due to the limited size of the site, it is recommended to test the resolution 720P or 1080P line of the splicing screen) to achieve the best results of their respective products. best effect. Beginning at the specified time, a review team will be composed of a number of experts with rich experience in image transmission, video display, and LED large-screen hardware to evaluate the actual application effect. 2. Evaluation requirements for small-pitch LED displays (1) Grayscale image test ①Grayscale and color scale tests have always been an important indicator reference for large screens such as DLP/plasma/LCD/LED or spliced large screens, and are used to evaluate the gray scale transition capabilities of large screen splicing and controllers (if any), and Black and white conversion capability, etc. The more obvious the contrast, the stronger the ability of the display system to process the color picture. The bidirectional grayscale signal is used to test the at least 16 grayscale levels that the system should display. If each level can be distinguished, 3 points will be awarded; if there is less resolution, 1 point will be reduced, and the lowest point for this item is 0 points. 25 + 2 levels of gray scale images must be able to distinguish the darkest 3 gray levels A, B, C and the brightest 3 gray levels U, V, W on the screen at the same time. A, B, and C must have layers and cannot look black; similarly, U, V, W must also have layers and cannot look white. If there is any color/color cast in the large-screen image during playback, points should be deducted. If there is no color difference (black and white impurity and other colors), add 2 points. If there is color cast, deduct 1 to 2 points as appropriate. ②Comprehensive test of sharpness and gray scale. This scene is used to comprehensively test the line count, gray scale, geometric distortion and other performance of the entire system. Under 1080P (1920×1080), each gray level and number of lines should be clearly identifiable, and the black and white purity of the gray scale can also be tested. 1 point is deducted for one question; minimum 1 point. ③Grayscale real scene map. The more black and white levels are displayed, the better the gray scale processing capability of the system can be reflected. Minimum 2 points, maximum 5 points. (2) Color picture test ①Comprehensive test of the dark part of color pictures. This scene is a night scene, which focuses on the changes in the strength of color light and shade and halo, and is used to test the system's color, grayscale, and detail display and other performance. The boat on the left under the bridge and the top halo above the main tower and the cables on the bridge deck can be clearly distinguished, scoring 4 points. If there is a problem, 1-2 points will be deducted depending on the severity. If there is no problem in distinguishing light and dark changes in other details, add 1 point. ②Highlight detail test: A test of detail restoration ability based on bright white. The scene is a dining table and dressing table with relatively high brightness. The main test is the restoration ability of the white part of the system under high light and the dynamic range of grayscale. The details of the texture of the window curtain, cloth, brush and other objects should be completely preserved. All items are met, 5 points. If there is any non-compliance, 0.5 points will be deducted for each item, and a maximum of 2 points can be deducted in total. ③ Face detail sharpness test. This scene is a close-up static picture of a girl and flowers, reflecting the fidelity of the large-screen stitching system to various details such as skin color and spots on the face and the authenticity of the skin color. The total score is 5 points, if the facial details are not clear, 0.5 points will be deducted. If the facial color is impure, 1 point will be deducted ④ Color reproduction test. Mainly test the uniformity of color and the purity of white. It is very important to restore the various ingredients and fruit colors in the kitchen, the pure white crystals on the tray and the barrel of the colored pencil, the wood grain part, the grassland, and the cloud layer. If the white is impure, 1-3 points will be deducted depending on the purity of the color cast. The full score is 5 point . ⑤ Color saturation and detail test. The fluff at the edge of the ball of wool should be clearly visible, as should the grain of the spool and the padding. 5 points out of 5. If the fluff is not clear, 1 point will be deducted; if the texture of the spool is not clear, 1 point will be deducted; if the texture of the doily is not clear, 1 point will be deduct d. (3) Dynamic scene t st Waves and Reefs (ROCK&WAVE, Blu-ray video source: 00014.m2ts). This scene is a reef scene, which is used to test the image quality of the device against a static background containing a lot of small movements, especially the white balance and detail resolution. In addition, the Fog (water mist) produced by the waves at the 20-27s playback place should be clearly distinguished. 5 points for a full score, if the level of waves and reefs is not clear, 0.1 to 1 point will be deducted as appropriate. If the FOG is not clearly displayed, 0.5 to 2 points will be deducted as appropria e. ① Light and dark detail test (Tokyo Night, Blu-ray video source: 00019.m2ts). This scene is a moving image of the Tokyo night scene, which is mainly divided into 4 scenes: the tower illuminated by lights; the Christmas tree embedded with lights; the night scene of the bridge and both sides; the night scene around the Ferris wheel. The main test system is the color reproduction ability and the dynamic range of light and dark contrast during dynamic video playback. The mesh details in high-brightness neon lights, Christmas tree details, dark details on both sides of the bridge, bright parts of the Ferris wheel and dark details of the street should be completely preserved. The minimum score is 2 points, and the maximum score is 5 points (if the details and levels of each item are unclear, 0.1 to 1 point will be deducted as appropria e). ②Black and white contrast test (Black&White, Blu-ray video source: 00020.m2ts). It mainly tests the edge resolution ability of black and white scenes and black and white dressed people. The highest score is 5 points, and the black background and the edge of the black clothes can be clearly distinguished, and the score is 3 points. If the white background and the edge of the white clothes can be clearly distinguished, 2 points will be awarded. If the edge of the same color is unclear, 1 to 2 points will be deducted as appropri te. ③Color expressiveness: accessories (Accessory, blue light test source: 00021. m2ts). The main scenes are flowers and accessories (necklaces, gloves, feather accessories, etc.), mainly testing the permeability of colors and the texture of items. In addition, the display of the tiny fluttering details of feathers is also very important. The highest score is 5 points, if the level of the flower is not enough, 1 point will be deducted; if the feather details are not clear, 1 point will be deducted; if the color is not transparent, 1 point will be deduc ed. ④ Dark detail test (Black Image Blu-ray test source: 00027.m2ts). The more black and white levels are displayed, the better the system's ability to handle dark details, and the higher the number of gray levels that can be displayed and restored. If the black level is clearly distinguished, the full score is 10 points; if the level of the black part is insufficient, 2 to 6 points will be deducted as appropr ate. The rest of the tests will not be described in de ail. (4) Professional software testing (DisplayX se ies) ①Pure color: Black, RGB, P (purple), Y, C (cyan), White. Black and white and 6 solid colors are displayed, and the overall color is uneven, with a total deduction of 0 to 1 point, compared with the same period last year. If there is a bad pixel, 2 to 3 points will be deducted depending on the number of bad pixels, compared with the same period last year. Maximum 5 po nts. ②Color and gray scale: Gradient test (no polarization). The R/G/B three-color signal with chromaticity gradient from left to right and the Y/Purple/Cyan after the two colors are mixed are used to test the chromaticity and grayscale changes of the system. The gradient has no sense of step, that is, the smoother the transition, the higher the grayscale level of the system. The gradient of each color is transparent, and there are no faults and vertical steps, the full score for this item is 5 points. Different colors are graded according to the degree of severity, and 1-3 points will be deducted compared with the same period last ear. ③Full color gradient. Full chromatogram gradient and no polarization change, the brighter and more transparent the color, the better. If there are more steps in each color, the less ideal, the corresponding points shall be deducted during the evaluation; the closer the display of each color is to the vertical, it proves the gray scale of each color The more synchronized the changes, the better. Gradient and transparent, without faults and vertical steps, this item is 4 points. If there is no uneven color change during the gradient, another 1 point will be awarded for this item. Depending on the severity of color faults, 1 to 3 points will be deducted compared with the same period last year.

According to reports, a research team led by Professor Keon Jae of the Department of Materials Science and Engineering and Daesoo Kim, a professor of the Department of Biological Sciences, developed a flexible vertical Micro LED Mesh for Outdoor Media Façade (micro light emitting diode) (f-VLEDs) technology. At the same time, the team also successfully controlled animal behavior through the optogenetic stimulation of this Micro LED technology. Thanks to the characteristics of ultra-low power consumption, fast response speed and superior flexibility, flexible Micro LED has become a strong candidate for next-generation displays. However, previous Micro LED technology faced critical issues such as poor component efficiency, low thermal reliability, and insufficient interconnect technology for high-resolution Micro LED displays. The report pointed out that the research team designed a new transfer device and fabricated an f-VLED array (50×50) through the precise alignment of ACF bonding technology, using synchronous transfer and interconnection technology. Compared with lateral Micro LEDs, these f-VLEDs have 3 times higher optical power density (30 mW/mm2), and can improve thermal reliability and extend operating life by reducing the amount of heat generated inside thin-film LEDs. (Source: KAIST) It is reported that these f-VLEDs (thickness: 5 microns; size: under 80 microns) are suitable for optogenetic control of neuron cells and brain behavior. Optogenetic control, as opposed to electrical stimulation that triggers all neurons in the brain, stimulates specific excitatory or inhibitory neurons in localized cortical regions of the brain, facilitating precise analysis, as well as high-resolution mapping of animal brains and neuronal modulation. During the research, the team implanted the newly invented f-VLEDs into the narrow space between the skull of the mouse and the surface of its brain, and successfully controlled the mouse by illuminating the motor neurons on the two-dimensional cortical area deep in the brain surface. the behavior of. According to Professor Li, such flexible vertical Micro LEDs can be used in low-power smart watches, mobile device displays and wearable lighting products. In addition, this flexible optoelectronic device is also suitable for biomedical applications such as brain science, light therapy and contact lens biosensors. It is understood that the research results entitled "Optogenetic control of limb movement on the surface of the brain through flexible vertical light-emitting diodes" have been published in the journal "Nano Energy" in February 2018. It is reported that Professor Li recently established a start-up company (FRONICS) based on Micro LED technology and is looking for global partners to commercialize Micro LED.

According to reports, a research team led by Professor Keon Jae of the Department of Materials Science and Engineering and Daesoo Kim, a professor of the Department of Biological Sciences, developed a flexible vertical Micro LED (micro light emitting diode) (f-VLEDs) technology. At the same time, the team also successfully controlled animal behavior through the optogenetic stimulation of this Micro LED technology. Thanks to the characteristics of ultra-low power consumption, fast response speed and superior flexibility, flexible Micro LED has become a strong candidate for next-generation displays. However, previous Micro LED technology faced critical issues such as poor component efficiency, low thermal reliability, and insufficient interconnect technology for high-resolution Micro LED Mesh for Outdoor Media Façade displays. The report pointed out that the research team designed a new transfer device and fabricated an f-VLED array (50×50) through the precise alignment of ACF bonding technology, using synchronous transfer and interconnection technology. Compared with lateral Micro LEDs, these f-VLEDs have 3 times higher optical power density (30 mW/mm2), and can improve thermal reliability and extend operating life by reducing the amount of heat generated inside thin-film LEDs. (Source: KAIST) It is reported that these f-VLEDs (thickness: 5 microns; size: under 80 microns) are suitable for optogenetic control of neuron cells and brain behavior. Optogenetic control, as opposed to electrical stimulation that triggers all neurons in the brain, stimulates specific excitatory or inhibitory neurons in localized cortical regions of the brain, facilitating precise analysis, as well as high-resolution mapping of animal brains and neuronal modulation. During the research, the team implanted the newly invented f-VLEDs into the narrow space between the skull of the mouse and the surface of its brain, and successfully controlled the mouse by illuminating the motor neurons on the two-dimensional cortical area deep in the brain surface. the behavior of. According to Professor Li, such flexible vertical Micro LEDs can be used in low-power smart watches, mobile device displays and wearable lighting products. In addition, this flexible optoelectronic device is also suitable for biomedical applications such as brain science, light therapy and contact lens biosensors. It is understood that the research results entitled "Optogenetic control of limb movement on the surface of the brain through flexible vertical light-emitting diodes" have been published in the journal "Nano Energy" in February 2018. It is reported that Professor Li recently established a start-up company (FRONICS) based on Micro LED technology and is looking for global partners to commercialize Micro LED.