Design of LED Dot Matrix Screen Based on 51 Single Chip Microcomputer

LED dot matrix screen has strong luminous brightness and good indication effect. It can make moving luminous graphics and texts, which is easier to attract people's attention. It has a large amount of information and can be updated at any time. It has a very good advertising and notice effect. The author here makes a brief introduction to the dynamic scanning display of LED dot matrix screen.1. Overview of LED dot matrix display principleFigure 1-1 shows the internal equivalent circuit diagram of an 8X8 LED dot matrix monochrome line common Yang module. For red LED, its working forward voltage is about 1.8V, its continuous working forward current is generally about 10mA, and the peak current can be greater. As shown in the figure below, when a row line is high and a column line is low, the intersection points of its rows and columns are lit. When a row line is low, regardless of the column line, all the points of the corresponding row are dark. LED dot matrix screen display is to scan line by line through a certain frequency, and the data end continuously inputs data for display. As long as the scanning frequency is high enough, due to the visual residual effect of human eyes, you can see the complete text or pattern information. Generally, there are 4, 8 and 16 line scanning modes. The fewer scanning lines, the better the display brightness of the dot matrix, but the corresponding hardware data register needs more.Figure 1-1 internal schematic diagram of dot matrix2. Hardware designThe IO port of the microcontroller cannot flow excessive current. When the LED is lit, there is about 10ms of current. Therefore, the LED dot matrix pin should not be directly connected to the IO port of the MCU, but should first pass through a buffer 74hc573. The IO port of single chip microcomputer only needs a small current to control 74hc573, which can indirectly control a row (or a column) of LED dot matrix, and the output of 74hc573 can also load about 10ms of current. Set the driving current of each LED point as id = 15mA, which has good lighting degree and certain margin. Even if the power output voltage is high, the LED will not be burned. The current limiting resistance value r = (VCC - VCE Vol VLED) / idvcc is 5V power supply, VCE is the saturation voltage between triode C and E, estimated to be 0.2V, Vol is 74hc573, and outputs low level voltage. This value is different for different perfusion currents, It is estimated to be 0.2V. According to the specification, VLED is the red light driving voltage, estimated to be 1.7V. According to the above formula, the current limiting resistance is r = 200R.The LED dot matrix screen needs to receive scanning signals one by one and scan to the corresponding column (or row). The data of the corresponding column (or row) is valid, that is, the information of this column (or row) is displayed. Generally, it is necessary to use a special decoder to generate the scanning signal, such as the three wire eight wire decoder 74HC138. In this way, the hardware can ensure that only one column (or row) is scanning at any time, and the occupation of IO port of microcontroller can be reduced. The 51 development board on the market basically does not use a decoder for the design of LED dot matrix screen. It directly uses MCU IO to generate scanning signal. For compatible software, the author does not add a decoder here. The software ensures that the IO port generates corresponding scanning signal.When the LED points of a column (or row) are on, the current of about 15max8 = 90mA flows through the common end of this column (or row). The IO port of the microcontroller cannot directly drive this current, so it needs to be driven by a triode. Because the low-level perfusion current of 51 single chip microcomputer is large, it is suitable to use PNP triode as the drive. When the base current of the triode is set to 2mA, the triode can be saturated, and the maximum driving current is much greater than 90mA. Base bias resistance RB = (VCC - veb vol) / ibvcc is 5V power supply, veb is the conduction voltage between triode E and B of 0.7V, Vol is the low-level voltage output by IO port of single chip microcomputer, which can be estimated as 0.2V according to the specification, so RB = 2K.Figure 2-1 schematic diagram of 8x8 common cathode LED dot matrix3. Driver implementationThe LED dot matrix data port is connected to port P0, and the scanning selection line is connected to bits 0 7 of port P2. For dynamic scanning, there is a scanning frequency. The lower limit of LED screen scanning frequency is 50Hz. If it is lower than a certain scanning frequency, the display will flash. If the frequency is too high, the brightness is poor and CPU resources are occupied. Generally, the scanning time of the whole screen is about 10ms (i.e. the scanning frequency is 100Hz). We adopt the 8-line scanning mode. The lighting time of each line is 1.5ms and the scanning time is 12ms. To ensure this refresh rate, the dot matrix screen is usually refreshed periodically through a timer.The display screen often involves complex operations such as drawing points, lines and drawings. Changing the information of the screen only needs to process the data in the video memory. Therefore, for the display screen, it is necessary to open up a memory space for video memory. Each point of 8x8 dot matrix can be represented by 1 bit, 1 byte per line and 8 bytes of video memory. Because there are too few pixels on the dot matrix screen, it is not necessary to realize complex operations such as line drawing and drawing. Here, the author only realizes the code implementation of dot matrix screen drawing and text moving up, down, left and right.The matrix. C file of dot matrix screen dynamic display function module is as follows:#includereg52.h#includeMatrix.h//Each LED point needs 1 bit to save, and 8x8 dot matrix needs 8 bytes of video memory//The external module obtains the memory location of video memory through this function for processingreturn FrameBuffer;//Dot matrix refresh ensures that the refresh is called in a certain cycleStatic unsigned char select = 0; / / record the scanned selection line//Column data output to lattice data port//The scanning signal is output to the dot matrix scanning selection portSelect ; / / enter the next line of scanningSelect = 0; / / all lines have been scanned. Return to the first line and start scanning again//LED dot matrix screen dotting function to light and turn off the (x, y) position, and the state is reversedIf (x "7" | Y "7) / / ensure that the position is within the dot matrix screen areareturn;Case set: / / (x, y) position is set, and the lamp is offbreak;The case clear: / / (x, y) position is cleared and the light is onbreak;The case negate: / / (x, y) position is reversed, and the lamp state changesbreak;break;//The LED dot matrix screen is clear, the display memory corresponds to the position of 1, the light is off, and the corresponding light of 0 is onunsigned char i;//Lattice translation, translation 1 in four directions up, down, left and right, and the translation vacancy position is filled with data fillingunsigned char i;Switch (direction) / / judge the direction of balanceCase move_up: / / shift 1 upward, shift the 7th bit to the 6th bit of each column of data, and so onbreak;Case move_down: / / shift down by 1, shift the 0 of each column of data to the 1, and so onbreak;Case move_left: / / shift 1 to the left, move the data in the right column to the current column, and so onbreak;Case move_right: / / shift 1 to the right, move the data in the left column to the current column, and so onbreak;break;We implement the macro definition and interface access macro implementation of the module in the dot matrix screen module header file matrix. H, so that it is convenient to transplant and modify the interface configuration. The module header file also leads to the interface function of the module. For example, matrixscan() is the dot matrix screen refresh function, which needs to be called periodically to refresh the dot matrix screen display. The contents of the dot matrix screen dynamic display function module file matrix. H are as follows:#ifndef__Matrix_H__#define__Matrix_H__#ifdef__cplusplusexternC #endif#Define set 0x1 / / set to 1#Define clear 0x2 / / clear 0#Define negate 0x3 / / reverse operation#Definemove_up 0x1 / / PAN up 1#Definemove_down 0x2 / / pan down 1#Definemove_left 0x3 / / PAN left 1#Definemove_right 0x4 / / PAN right 1//Output column data to port P0//The P2 port outputs the scanning selection line of the corresponding column, and the low is valid#ifdef__cplusplus#endif#endif/*__Matrix_H__*/The external application calls the lattice screen driving function by introducing the lattice screen module header file matrix. H. The simple test call (random translation of heart shape in the lattice screen) is realized as follows:#includereg52.h#includeMatrix.h//Cardioid coordinate dataSource; 21IC

Do you remember the wonderful moment when fireworks bloomed? When I was a child, I always hoped that I could leave the most beautiful moment forever. Finally, today my dream came true. Through their own board, just program a few times!Before showing you the renderings, we must first introduce the LED dot matrix screen! The equivalent circuit of 8 * 8 LED dot matrix is shown in Figure 1. Through analysis, it is not difficult for us to know that as long as the corresponding x-axis and y-axis forward bias, the LED can be lit. For example, if you want to turn on the LED in the upper left corner, Y0 = 1 and x0 = 0, a voltage drop will be formed to turn on the LED in the upper left corner. Here, the horizontal direction is controlled by P2 and the vertical direction is controlled by P0.Fig. 1 equivalent circuit of 8 * 8 LED dot matrixThe functional principle interface diagram of displaying fireworks on the LED dot matrix screen is shown in Figure 2, and the effect diagram is shown in Figure 3. The LED dot matrix can also display static or dynamic graphics, text, etc. If you are interested, you can try it yourselfFig. 2 functional principle interface diagram of displaying fireworks on LED dot matrix screenFig. 3 fireworks display effect groupFigure dynamic display of fireworksDisplay fireworks C source code on LED dot matrix screen#include#include#define uint unsigned int#define uchar unsigned charP0=0;

Do you remember the wonderful moment when fireworks bloomed? When I was a child, I always hoped that I could leave the most beautiful moment forever. Finally, today my dream came true. Through their own board, just program a few times!Before showing you the renderings, we must first introduce the LED dot matrix screen! The equivalent circuit of 8 * 8 LED dot matrix is shown in Figure 1. Through analysis, it is not difficult for us to know that as long as the corresponding x-axis and y-axis forward bias, the LED can be lit. For example, if you want to turn on the LED in the upper left corner, Y0 = 1 and x0 = 0, a voltage drop will be formed to turn on the LED in the upper left corner. Here, the horizontal direction is controlled by P2 and the vertical direction is controlled by P0.Fig. 1 equivalent circuit of 8 * 8 LED dot matrixThe functional principle interface diagram of displaying fireworks on the LED dot matrix screen is shown in Figure 2, and the effect diagram is shown in Figure 3. The LED dot matrix can also display static or dynamic graphics, text, etc. If you are interested, you can try it yourselfFig. 2 functional principle interface diagram of displaying fireworks on LED dot matrix screenFig. 3 fireworks display effect groupFigure dynamic display of fireworksDisplay fireworks C source code on LED dot matrix screen#include#include#define uint unsigned int#define uchar unsigned charP0=0;

It is reported that Apple plans to use cheaper LCD screens on most iPhone models next year, while delaying the full conversion to high-tech organic light emitting diode (OLED) screens, which also reflects consumers' price sensitivity.According to the Wall Street Journal, apple is expected to launch an LCD model and two OLED models this fall, and the LCD model is expected to account for most of its iPhone sales. It is expected that Apple will continue to use LCD next year, which is completely inconsistent with the previous report of a complete transition to OLED.Apple announced in March that it was testing its internal microled screen.Apple's decision to insist on using cheaper LCD screens has brought more uncertainty to its screen suppliers; In addition, Apple's decision to produce its own screen endangers the interests of many suppliers.Since apple is not expected to use these products in its OLED screen, the shares of Apple's three LCD suppliers, including sharp, LG display and Japan display, have fallen sharply in the past year. Subsequently, when it was revealed in March that Apple was already testing its microled screen, the shares of many display suppliers, including Samsung, sharp and LG display, fell again. This also damages the interests of general display and Synaptics. After reports showed that Apple would use more LCD screens than expected, the share price of general display company, which provides OLED display materials, began to fall.The Wall Street Journal pointed out that Apple's decision to postpone the implementation of OLED screens does not necessarily bring opportunities for LCD suppliers. For example, LG display has planned to invest in OLED screens.Apple has been facing the problem of supply shortage in the past. If suppliers have to change their production plans, Apple may face supply shortage again. It is reported that Japan display raised $320 million in April to meet the expected demand for its advanced LCD.According to recent reports, Apple has communicated its transformation plan to its suppliers, including plans to reduce parts procurement from suppliers by nearly 20% this year. At the same time, the uncertainty of the continuous expansion of Apple's supply chain will also make the new iPhone more expensive than ever.

It is reported that Apple plans to use cheaper LCD screens on most iPhone models next year, while delaying the full conversion to high-tech organic light emitting diode (OLED) screens, which also reflects consumers' price sensitivity.According to the Wall Street Journal, apple is expected to launch an LCD model and two OLED models this fall, and the LCD model is expected to account for most of its iPhone sales. It is expected that Apple will continue to use LCD next year, which is completely inconsistent with the previous report of a complete transition to OLED.Apple announced in March that it was testing its internal microled screen.Apple's decision to insist on using cheaper LCD screens has brought more uncertainty to its screen suppliers; In addition, Apple's decision to produce its own screen endangers the interests of many suppliers.Since apple is not expected to use these products in its OLED screen, the shares of Apple's three LCD suppliers, including sharp, LG display and Japan display, have fallen sharply in the past year. Subsequently, when it was revealed in March that Apple was already testing its microled screen, the shares of many display suppliers, including Samsung, sharp and LG display, fell again. This also damages the interests of general display and Synaptics. After reports showed that Apple would use more LCD screens than expected, the share price of general display company, which provides OLED display materials, began to fall.The Wall Street Journal pointed out that Apple's decision to postpone the implementation of OLED screens does not necessarily bring opportunities for LCD suppliers. For example, LG display has planned to invest in OLED screens.Apple has been facing the problem of supply shortage in the past. If suppliers have to change their production plans, Apple may face supply shortage again. It is reported that Japan display raised $320 million in April to meet the expected demand for its advanced LCD.According to recent reports, Apple has communicated its transformation plan to its suppliers, including plans to reduce parts procurement from suppliers by nearly 20% this year. At the same time, the uncertainty of the continuous expansion of Apple's supply chain will also make the new iPhone more expensive than ever.

Led transparent screen is a popular subdivision screen in the LED field in recent years. We often see the figure of transparent screen whether it is glass curtain wall, glass window or shopping mall. As one of the high-end display products, the price problem of the original transparent screen makes many users can only wait and see from a distance.With the rapid development of LED transparent screen, its price has also decreased significantly to the acceptable range of users, and various spacing and special-shaped display products emerge in endlessly. Transparent screen is gradually emerging in the commercial display field because of its unique display style.Scientific and technological progress is the core of social development and the first productive force. The transformation and upgrading of science and technology has not only greatly improved the modern production capacity of enterprises, but also further improved human vision in social development. In recent years, with the strong support of the construction industry in big cities, the glass curtain wall area of commercial buildings has reached a new peak. In this regard, led transparent screen manufacturers have made major technical upgrades to the transparent display scheme of large-area glass curtain wall. As a provider of indoor and outdoor LED transparent screen display solutions, Shenzhen Jingang vision is also very happy to contribute to our strength under the mainstream of this market.In order to expand the scope of commercial display application market, we continue to integrate new technologies and introduce various innovative technologies, products and solutions to the market. In recent years, led transparent screen solutions have become more and more common due to the use of advanced technology and most market participation. This popularity has also prompted the outbreak of urban commercial exhibition industry, which is also due to the continuous improvement of infrastructure and the rapid development of urbanization.When it comes to transparent screens, the market segments are relatively broad, and the market segments are based on products, technologies, components, display types, screen sizes and application scenarios. Based on various segments, led transparent screen can help enterprises choose growth niche market and strategic development, and determine the difference between the core application field of products and the target market.

Principle of touch screen capacitance screenTouch screen is the most friendly computer user interface at present. It is more and more widely used in consumer electronic products. The touch detection device and touch screen controller are good. The mechanical structure of the detection device is damaged in the process of touch screen device, resulting in the decline of touch accuracy and shortening of service life of the touch screen; In addition, the cost of commonly used capacitive and resistive touch screens is relatively high. Inductive touch screen can avoid damage to the touch detection device during touch and prolong the service life of touch screen products.The working principle of inductive touch screen, as well as the hardware circuit and part of the program design of the controller, all of the controller circuits have passed the verification. The non-direct contact touch of inductive touch screen avoids the damage to the touch detection device, prolongs the service life of the whole touch control system, and the repetition accuracy and touch sensitivity of touching the same point meet the expected design requirements.The capacitive induction touch screen is not affected by dirt, dust or oil stains, but it will be affected by the surrounding environment to varying degrees because it adopts the electric field coupling principle. At the same time, the capacitive induction touch screen has serious drift phenomenon.What are the application areas of touch screenTouch screen has become a hot spot in the market. In the market, shopping malls, hotels and other places, it is still dominated by smart phones. The growth momentum of the smartphone market slowed down and entered a period of gentle development. The application of touch screen outside mobile phones, such as automotive electronics, retail, medical treatment, public facilities, leisure and entertainment, will promote the rapid growth of touch screen market.In addition to applications in large fields, touch screens can be innovated in subdivided fields. In the field of "pen writing tablet", innovate the touch screen.The products have been extended to tablet with pen writing function, e-book, all-in-one machine, electronic whiteboard, etc. And the pen and hand can be used at the same time. When one hand is touching, the pen can also write at the same time.The traditional materials of capacitive touch screen are ITO, metal grid, nano silver wire, carbon nanotube, conductive polymer, graphene, etc. Metal mesh and nano silver wire have more supporters. Both materials are metals (silver or copper) and their conductivity is better than ITO.

Fingerprint identification on mobile phones has become an indispensable part of our daily life.Especially during the epidemic, face recognition is mostly paralyzed due to wearing masks, and fingerprint recognition has become the current optimal solution.Of course, if you use a mobile phone without fingerprint identification such as iPhone x, you have to find a way by yourself...9to5mac also gave a tutorial on using face ID with mask Screen fingerprint identification has become the mainstream, and the technology is also very mature. However, Tony saw a news while surfing the Internet today, saying that Tianma, a domestic LCD and LCM design company, released the world's first LCD Screen multi-point fingerprint identification scheme (Ted finger print, referred to as TFP).The strength of this scheme is that the off-screen fingerprint identification mobile phones we use now are basically OLED screens, while the LCD screen basically has no on-screen fingerprint identification...One plus 6T off screen fingerprint identification diagram As we all know, the screen fingerprint unlocking needs the illumination of the light source for fingerprint identification, but the LCD screen is relatively thick and has poor light transmittance; Second, the LCD screen cannot emit light actively, and the backlight will interfere with the identification of optical fingerprints.These two problems make LCD basically bid farewell to screen fingerprint recognition.Therefore, mobile phones with LCD screen basically adopt side fingerprint identification, and some will be combined with the power key on the side of the mobile phone.But OLED screens don't have this problem. Because the OLED screen is thinner and more transparent, it is natural to use fingerprints on and off the screen.Then why do manufacturers not directly on the OLED screen, but want to operate madly on the LCD screen? The reason is also simple: because LCD screens are cheap...Although Lu Weibing, vice president of Xiaomi, said publicly some time ago that Hongmi team successfully realized fingerprint recognition under LCD screen on a redmi note8 Pro prototype, so far, no manufacturer has officially announced this technology, and Tianma is the first.So Tony was surprised when he saw the news. This fingerprint identification scheme can be said to break through the two obstacles of current screen fingerprint identification technology - LCD screen and identification area.If the multi-point fingerprint identification in the LCD screen can achieve mass production, it means that the LCD screen can also use fingerprint identification!Another point is the identification area of off screen fingerprint identification.So far, the identification area of screen fingerprint is basically fixed, almost at the lower position of the screen. People will subconsciously put their fingers at the approximate position when unlocking the mobile phone.But no one can guarantee that every time the finger is pressed on the fingerprint identification area, because the identification area is so large, it is inevitable that there will be deviations...The scheme announced by Tianma this time shows that it can make the whole LCD screen recognize fingerprints!Tony mended his brain, that is, I could identify my fingerprint and unlock my mobile phone by placing my finger anywhere on the screen.If this multi-point fingerprint identification technology can be mass produced, the efficiency of unlocking the screen will be much higher than now. You don't have to find the identification area and poke it on the screen.It can be said that Tianma's operation directly makes the LCD screen ride on the head of OLED in fingerprint identification. Once LCD screens didn't even deserve fingerprint identification. Now they not only have fingerprint identification, but also can identify 5 at a time...As for why the multi-point fingerprint solution in the TFP screen can realize these functions, high integration has played a great role.In short, it is to integrate touch, display and fingerprint identification, replace the previous design of fingerprint identification module and reduce the thickness of the screen, so that the screen fingerprint identification is feasible on the LCD.At the same time, in order to realize fingerprint identification on the whole screen, Tianma covers the whole screen with optical path and sensors.As for how multi-point fingerprint identification can play new tricks, it still depends on the subsequent operations of manufacturers.As for the fate of LCD screen after mass production of this scheme, we still don't know, but before that, LCD screen has never been the first choice for mobile phone manufacturers.After all, the OLED screen is thinner, can emit light by itself, and the color is more bright. The experience is much better than that of LCD, but there are still problems of stroboscopic and screen burning, and the price is relatively expensive.When it comes to the LCD screen, the advantages and disadvantages are reversed...The price of iPhone 11 with LCD screen is lower For most users, OLED screen is their first choice, but there are still a group of people who stick to the LCD screen.In addition to having a larger viewing angle, another reason is that they can't accept the strobe of OLED screen. They think it's really hurting their eyes...Therefore, once the TFP scheme realizes mass production, the defect that the LCD screen has no off screen fingerprint will be supplemented. If the price can be controlled well, the current situation of the screen in the mobile phone market may change a lot.However, before that, the mobile phone market was still dominated by OLED screens, not to mention the suoper AMOLED screens such as Samsung. The evolution of LCD screens has a long way to go...

Every day, new products, new experiences, professional membrane switch proofing factory, 12 hour expedited shipmentFrom the hot sale of Samsung Galaxy edge flagship series to the advent of various curved screen bracelets and TVs, it is no doubt that curved screen technology has been widely valued and sought after by consumers and the industry in recent years. In the future, with the continuous development and improvement of fixed curvature curved screen technology, the flexible touch screen that can realize arbitrary bending will become an important development direction. On the 25th, at the 13th International touch screen and display technology development forum, Huang Hanfeng, deputy general manager of touch R & D from Shenzhen oufeiguang technology, made a detailed introduction to the flexible touch screen from the perspective of the industrial chain around the four key elements of flexible display, flexible touch, flexible cover plate and flexible bonding.Flexible displayFor LCD display, the LCD is usually responsible for controlling the display gray, and the three primary color filters control the display color, which requires them to correspond one by one in order to display normally. If the LCD panel is used as a curved screen, the inner circumference and outer circumference will be unequal, and the original one-to-one corresponding liquid crystal and filter will have position deviation, resulting in color distortion. In addition, it will also cause a series of problems such as light leakage, dark screen ghosting and snowflakes. Therefore, for the curved screen, the OLED display technology represented by AMOLED has almost become the best choice.Huang Hanfeng said that at present, Samsung is the undisputed AMOLED overlord in terms of patents, production capacity, yield and technology accumulation. The sixth generation AMOLED panel that began mass production at the end of 2014 can now produce 50000 pieces per month, and the yield can reach 60%. The second is LG, but LG has been focusing on large screen curved TV. At present, with the increasingly obvious trend of small screen AMOLED, LG is also accelerating the layout of small and medium-sized flexible screens. Although its output is not as good as Samsung, its yield can also reach more than 60%. The latest release of Xiaomi note 2 is the flexible AMOLED screen of LG. In addition, Japan's JDI and sharp (already acquired by Hon Hai), Taiwan's Youda, domestic BOE, Rouyu and other screen manufacturers are also accelerating the layout of their own AMOLED technology. It is the general trend for AMOLED to replace LCD.Flexible touchIn terms of touch control, ITO (indium tin oxide) transparent conductive film has become the most important touch layer material for display screens such as non curved LCD and OLED due to its good light transmittance, low thickness, excellent hardness and conductivity, mature manufacturing technology and many other reasons. However, as ITO itself is a brittle material, it is not suitable for making flexible touch layer with large curvature or even free bending, and the cost and cost are high. At present, it accounts for about 30% - 40% of the cost of the upstream material part of the whole touch screen industry, and uses "indium", a rare metal with limited reserves. Therefore, with the advent of the era of curved surface and flexibility, it is likely to be replaced.Huang Hanfeng said that at present, the main substitutes for ITO materials are graphene, carbon nanotubes, nano silver and metal mesh. Graphene and carbon nanotubes are very good substitutes for ITO from the characteristics of the material itself. However, graphene is still in the R & D stage and is still far from mass production. The industrial mass production technology of carbon nanotubes is not perfect, and the conductivity of the thin film products made of carbon nanotubes is not as good as that of ITO. Therefore, from the perspective of technology and marketization, metal grid and nano silver technology will be the protagonists of development in recent years. Metal grid technology has been applied in some PC display markets.The metal mesh technology mentioned here is a conductive metal mesh formed by pressing metal conductive materials such as silver and copper or oxides on thin film substrates such as pet. Its main advantages are low raw material cost and good folding ability. However, due to the problem of Murray interference ripple caused by yield, output and high-speed pixels, it is more suitable for desktop all-in-one computers, laptops, televisions and other products with low resolution and relatively long-distance use.Nano silver technology means that nano silver ink material is coated on pet or glass substrate, and then laser lithography is used to depict the conductive network of nano silver wire. Its main advantages are high yield, small linewidth, good conductivity and folding resistance, while its disadvantage is high cost. Moreover, compared with metal mesh, nano silver material has smaller radius of curvature and small resistance change rate during bending. In addition, due to the linewidth, it is more suitable for high-resolution close-up scenes such as mobile phones, smart watches and bracelets."By comprehensive comparison, I think nano silver has more advantages than metal grid," Huang Hanfeng said.Flexible cover plateIn order to bend at will, in addition to solving the flexible display and flexible touch, the last and most critical part is the flexible cover plate and fitting. However, due to its hard and fragile characteristics, glass cover plate is not the best choice in the field of flexibility.Huang Hanfeng said that compared with glass, pet and PI (polyimide) materials with high surface hardness and high light transmittance are better choices, but at present, pet and PI also have many problems to be solved. On the one hand, they are not resistant to high temperature and have poor light transmittance: pet and PI will have problems of partial melting and property change at low ambient temperature, and they do not have good light transmittance compared with glass.Secondly, it is difficult to achieve a balance between hardness and folding. Huang Hanfeng said that if you want to meet certain hardness requirements, you need to apply the hardened layer, but after coating the hardened layer, after repeated folding, the hardened layer will crack and reduce the hardness. Therefore, how to achieve a balance between the two is the biggest bottleneck at present.Compared with the flexible cover plate that needs further development, the 3D glass cover plate necessary for curved screen mobile phones has a very good development prospect.Some data show that 2018 may become the outbreak year of 3D glass cover plate. It is expected that the mobile phone penetration rate of 3D glass cover plate will exceed 50% around 2020. With the maturity of 3D glass cover plate processing technology and the decline of unit price, the penetration rate will further improve. It is expected that the market scale will reach more than 19 billion yuan in the future.Huang Hanfeng said that the common manufacturing processes of 1R (single radian bending) and 2R cover plates have been basically mature. They basically achieve a bending effect through hot bending technology. The difference is mainly in the coating of hardened layer. However, the yield is a problem to be solved, which is basically only 30%, and there is no room for improvement in the short term. If 4R is to be done in the future, the yield will be lower. Therefore, the yield is one of the urgent problems to be solved in the manufacture of cover plate.Flexible fitAfter the cover plate is selected, it is fitted, that is, the cover plate is integrated with the touch and display layer below to form a complete module. At present, there are two common methods: roller type and vacuum bonding: the roller has high efficiency and needs to roll the pasted object. The efficiency of vacuum type is relatively low, but it does not need to roll the pasted object, so it is not easy to cause damage to the pasted object.Huang Hanfeng said that if the curvature is large, you can only choose vacuum bonding. However, for the possible 4R bonding in the future, due to its special four side bending characteristics, it is difficult to avoid wrinkles and bubbles in places with large radians even if vacuum is adopted. At present, the industry has adopted customized extrusion airbags or plastic parts to alleviate this problem, but it has not been completely solved. Therefore, the industry still has room for progress in multi surface and high curvature fitting technology.Huang Hanfeng frankly said: "from the perspective of the supply chain, it will take several years for the flexible screen to really realize mass production. At the same time, it also needs the upstream and downstream supply chain to jointly overcome the relevant technical problems."For future development, Huang Hanfeng believes that the integration of various modules will be the general trend. He said: "in the incell technology of LCD, ITO touch film and liquid crystal layer are integrated together, which is a good integration. Now the fingerprint module is independent, and it can also be integrated with touch in the future. I think there will be a process of mutual integration and progress between functional modules in the future."

In the early morning of June 20, Beijing time, according to the English version of Korea Times, in order to further consolidate the leading position in the display market, LG display will mass produce a new version of smart phone flexible display from the fourth quarter of this year and provide it to major customers.LG researchers and technicians said that the purpose of producing flexible display is to meet the growing demand for innovative solutions. LG spokesman Frank Lee said that the company is trying to meet the rapidly growing market demand for advanced display screens. Li stressed that the new display screen is foldable and not fragile, and the product will become a major innovation in display technology.LG said it was investing in flexible displays and high-tech panels for mobile devices, namely OLED panels that support high-definition (UHD) displays. "We have completed the development of the first flexible display and will start mass production from the fourth quarter of this year," LG said in a statementThe E2 production line of the company's display manufacturing plant in pozhou, South Korea, will be responsible for the production of flexible displays. LG said that the OLED flexible display will adopt generation 4.5 glass cutting technology, and the monthly production capacity of the production line will be 12000 pieces.Koo Bon moo, chairman of LG, hopes to revive the enterprise by launching leading products. Therefore, as a major shareholder of LG display, LG Electronics will launch its first flexible display smartphone later this year.LG predicts that flexible display may become the latest trend of mobile devices, so the company may also consider selling flexible display to major mobile device manufacturers.It is reported that LG's competitor Samsung display is also developing similar products. At present, Samsung display is testing flexible display products to improve product quality. Due to manufacturing problems, the upcoming Galaxy note 3 should not be configured with a flexible display in the short term.Kim Yang Jae, an analyst at Woori investment securities in Korea, said: "mobile phone manufacturers are increasingly pursuing bright images, beautiful shapes and thin display screens, while flexible display screens cater to this demand. LG display is expected to help them seize a greater market share." Kim said, LG's strategy of switching to flexible display can break the industry conventions and make the company earn stable profits.In fact, flexible display is only one step for LG to invest in different businesses and seize the global market share of OLED. LG is the first company to mass produce OLED display and foldable OLED screen. At the same time, the company is also developing OLED TV supporting high-definition display.Lim Joo soo, manager of LG OLED Technology Strategy Department, said that in order to remain competitive, LG is trying to reduce costs, reduce power consumption and improve image quality. Lim Joo soo said: "LG display is developing high-definition OLED TV screen. In order to improve the brightness, we plan to replace the existing 'bottom light' technology with 'top light' technology. In addition, the company will develop new materials to extend the service life of OLED display."In the next few years, OLED TV will become the mainstream product, and LG plans to expand the TV screen size to 65 inches and 77 inches. LG said that the above two OLED displays will be produced by the M1 test production line of pozhou factory.