Introduction to Dfroboti2c Oled-2864 Display

Overvoltage protection circuit technology of DC-DC converter for spacecraftIn the design of DC-DC converter, the protection of electric load and the protection of DC-DC converter due to the failure of electric load should be considered. Due to the special requirements of high reliability and non maintainability of DC-DC converter for spacecraft, failure mode and impact analysis should be carried out at the beginning of design, that is, considering the impact of various faults that may occur in all components and components of DC-DC converter on DC-DC converter, as well as corresponding corrective measures in design, so as to ensure that it will not cause disastrous consequences.The stability requirements of electronic circuit loads on the power supply are generally not more than 1% of the power supply voltage and not more than 5% in extreme cases. The stability requirements of electromechanical loads on the power supply are relatively wide. In order to ensure the safe and reliable operation of electrical equipment, overvoltage protection circuit should be designed according to various failure modes of components and line elements in the circuit. Irrelevant double faults are not considered in the analysis of overvoltage failure mode, that is, it is considered that the simultaneous failure of different components of two unrelated circuits is a minimum probability event.Failure mode analysis of overvoltage of secondary power supplyDC-DC converter is a closed-loop feedback system. The fault points of output overvoltage caused by different circuit topologies are different. For example, for a non isolated buck converter, once the drain source of the series power MOSFET is short circuited, the input voltage will be directly connected to the output. For another example, the multi-channel output DC-DC converter using magnetic isolation sampling and output secondary voltage stabilization, and the input and output short circuit of the three terminal voltage regulator used for secondary voltage stabilization will also lead to output overvoltage. For another example, for a multi-channel output DC-DC converter, the difference in cross adjustment rate will increase the output voltage of a certain channel.For general single output isolated DC-DC converters, the failure modes that may cause output overvoltage are shown in Table 1. Design of general overvoltage protection circuitGenerally, the overvoltage protection at the output end can be realized by forced method, that is, overvoltage clamping and fast breaking. For example, the clamping output is realized by parallel connection of Zener diode or thyristor at the output end. See Figures 1 and 2.In addition to the fault mode of output overvoltage caused by transformer primary stage short circuit can be overcome by transformer insulation design, for the other overvoltage failure modes listed in Table 1, an output voltage limiting protection circuit based on PWM is designed in this paper.Output voltage limiting protection circuit based on PWM

High power LED can provide long working life, low power consumption and low maintenance requirements that incandescent lamp or CFL lamp cannot provide. These factors make led more and more popular in outdoor applications. However, LED is a sensitive electronic component, which is easily damaged by transient overvoltage and overcurrent caused by system switching, electrostatic discharge and adjacent lightning strikes. In addition, the switching power supply driving the LED does not provide transient overvoltage or overcurrent protection for the inductive LED lighting electronic ballast.In the application of street lights or airport runway lighting, a string of LED failure may lead to the overall light brightness darkening or completely blackening, resulting in unimaginable safety problems. In outdoor LED advertising display applications, this may produce white spots and lead to revenue loss. In any of the above applications, the failure of a string of LEDs often leads to expensive maintenance problems in outdoor applications.In order to solve this problem, many suppliers have successively launched led protection components of various sizes, such as Bourns, Littelfuse, te (former Tyco Electronics), ansenmey and Vishay. The next six months will be a period when the demand for high-power LED protection will change from low production cost, high maintenance rate and high maintenance cost to low maintenance rate, high reliability, low maintenance and even maintenance free cost. It is also a key time for LED protection components to be accepted and recognized by the market.The traditional LED protection mainly considers the surge caused by lightning and ESD, as well as the damage caused by the reverse connection of the positive and negative poles of the power supply. However, for the high-power LED applied to outdoor lighting, it is also necessary to consider how the LED string works reliably and reduce the maintenance cost. The LED protection elements launched by Bourns, Ritter and other suppliers can fully meet all the above requirements. The LED protection element can not only prevent lightning, surge and reverse connection, but also ensure the normal lighting of other LEDs when there is an open circuit caused by the damage of individual LEDs in the LED string.The LED protection element can also effectively protect the LED from the impact of adjacent surge voltage / current sources such as lightning strike and ESD discharge. In addition, the LED protection element contains a reverse current diode, which can protect the LED string from the reverse connection of power polarity.The LED protection element is connected in parallel with each LED in series. If an LED is open, the LED protection element connected to it will turn on and direct the current that should have passed through the fault led to the LED protection element. This ensures that other LEDs in the lamp string can work normally, so only a single LED is extinguished, while the whole lamp string can still work normally, greatly reducing the later maintenance cost of outdoor lighting.When not turned on, the LED protection element passes only a few microamperes of current, so it will not affect the whole circuit. In the triggered state, it will carry all the current of the lamp string and produce a voltage drop of about 1.3 volts.

Company name: Shanghai guangyuruixin Microelectronics Co., LtdEnglish Name: Shanghai Sino IC Microelectronics Co., LtdRegion: ShanghaiManufacturer type: Design Manufacturercompany website: http://www.sino-ic.netData provided by: Shanghai IC Industry AssociationCompany profileShanghai guangyuruixin Microelectronics Co., Ltd., located in Zhangjiang High Tech Park, Pudong, Shanghai, is a high-tech enterprise specializing in the design and sales of semiconductor overvoltage protection devices and integrated circuits. It is one of the domestic suppliers who master the core technology of semiconductor overvoltage protection devices and integrated circuit design. The company's main products include: interface protection of communication system, interface protection of portable products, overcharge and discharge protection of lithium battery, overvoltage protection of power supply system and led overvoltage protection devices; And regulators, power MOSFET devices, Schottky devices and led driving circuits.Benefiting from the rapid development of China's electronic information industry, the company consistently focuses on the improvement of technology, team construction, improvement of management, market development and innovation of operation mode. The company has achieved initial success in China's Microelectronic Design Industry; It has become the main design unit of semiconductor overvoltage protection devices in China. Its product quality, product specification and cost performance are leading in the industry, and has successfully developed a number of substitutes for similar foreign products.Adhering to the development concept of "people-oriented", the company strives to create a good working environment and first-class infrastructure for employees. At present, the company has gathered a high-quality talent team with doctors and masters as the main body, and its technical level and R & D scale are among the best in domestic peers.Ruixin microelectronics is based on the concept of customer first, coexistence and common prosperity with suppliers, each employee is a responsibility unit, and the company is a team; We are willing to sincerely cooperate with colleagues in the industry and customers from all walks of life, face opportunities, meet challenges and create the future with information technology.Company productsPower management chipOther chipsprotection circuit logical circuitElectronic componentsdiodetriodeField effect transistor

Today's mobile phones and other portable devices are becoming smaller and thinner. At the same time, they are integrating more and more new functions or features, such as large-size display screen, high-resolution camera module, high-speed data interface, Internet access, TV reception, etc., making the data rate and clock frequency of portable devices higher and higher. In this way, portable devices are faced with many potential electromagnetic interference (EMI) / radio frequency interference (RFI) sources, such as switching load, power supply voltage fluctuation, short circuit, inductive switch, lightning, switching power supply, RF amplifier and power amplifier, interconnection between ribbon cable and video display screen, high-frequency noise of clock signal, etc. Therefore, designers need to select a suitable EMI / RFI filtering scheme for portable devices according to multiple locations such as audio jack / headset, USB port, speaker, keyboard, microphone, camera and display interconnection.For EMI / RFI filters, from the perspective of architecture, the most common architecture is "Pi" filter. As the name suggests, this architecture is similar to the Greek letter "". There are two common type filters: c-r-c (capacitance resistance capacitance) filter and c-l-c (capacitance inductance capacitance) filter. Among them, c-r-c filter (see Figure 1a) is also known as RC - filter or RC filter, which is used for audio and low-speed data filtering applications; C-l-c filter (see Fig. 1b) is also called LC - filter or LC filter, which is used for audio, low-speed and high-speed data filtering applications. filter also has an expansion type, that is, ladder shaped filter. The most common is LC (inductance capacitance) ladder filter (see Fig. 1c). This filter bears higher data rate, but when the filter elements (inductance or capacitance) increase, the size and cost will become a problem, resulting in higher material cost and larger packaging.Figure 1: structural diagram of common EMI / RFI filter types: a) type RC; b) type LC; c) LC ladder.Among these types of EMI / RFI filters, from the comparison of frequency amplitude response, type RC filter has the widest transition band and the lowest rolloff; - type LC filter has low turning rate but moderate transition band; Trapezoidal filter can achieve very high turning rate and narrow transition bandwidth.In terms of EMI / RFI filtering, taking mobile phone applications as an example, a traditional reference frequency is 800 MHz, because 800 MHz is close to the starting frequency of the frequency band used by mobile phones. In most cases, mobile phone design engineers require filtering at frequencies above 800 MHz, which generally means a minimum signal attenuation of 30 dB. With the increase of functions in mobile phones and the classification of clock and data signals, the reference frequency is decreasing. Many portable electronics manufacturers require EMI / RFI filtering at 400 MHz and may require EMI / RFI filtering at lower frequencies in the future.Integrated EMI filtering and ESD protectionIn portable products, the filter is generally located adjacent to the connection port, microphone and speaker. These locations may also face electrostatic discharge (ESD) events. Taking the audio line as an example, if the discrete component scheme is adopted for EMI filtering and ESD protection respectively, the number of components required to perform these two functions will be faced. For EMI filter, if a discrete type LC filter is used, two surface mount capacitors and one surface mount inductor are required. In order to provide ESD protection, an additional type of surface mount transient voltage suppressor (TVS) diode needs to be added. In this way, EMI filtering and ESD protection of an audio line require four independent components. The precious space of portable devices occupied by these components has not been mentioned here. If there is more than one audio line, it is more impractical to adopt the discrete component scheme.Therefore, the simplest solution is to integrate EMI filtering and ESD protection functions in the same element. Firstly, the integrated TVS diode in the integration scheme also provides the capacitance required for EMI filtering; Secondly, improving the process technology can also greatly improve the quality of integrated inductors. By integrating these integrated components into the silicon wafer, the original scheme that requires multiple independent components can adopt the integrated EMI filtering ESD protection scheme (see Figure 2).Among them, in terms of ESD protection level, IEC61000-4-2 standard specifies the system level test conditions and protection levels in detail, which are divided into four types. Portable applications usually need level 4 protection, that is, under the IEC61000-4-2 test conditions of 8 kV contact discharge or 15 kV air discharge, portable equipment needs to be able to withstand the impact of ESD events.In general, by cost-effective integration of EMI filtering and ESD protection, portable application designers can reduce costs, reduce the number of bill of materials (BOM) components, and reduce the space occupied by circuit boards.EMI filtering ESD protection scheme for specific application of portable equipmentIn the portable device market, mobile phones occupy an important position. Naturally, many locations in the mobile phone will be applied to filters with integrated ESD protection. For mobile phone applications, in addition to LC and RC filters, there are common mode choke EMI filters, which help reduce parasitic inductance and provide better common mode filtering. The type bandwidth spectrum of these mobile phone filters is shown in Figure 3.Figure 3: bandwidth spectrum of mobile phone filter type.Different mobile phone applications need different filters. Generally speaking, the higher the data rate of the application, the smaller the total capacitance of the filter line. For mobile phone applications with relatively low data rate such as audio lines, the standard capacitance of EMI filter in the range of hundreds of PF is enough to provide excellent filtering performance and minimum signal interference.Among them, in audio applications such as speakers, microphones, audio jacks / headphones, LC or RC filters can be selected, such as nuf2441fct1g, nuf2450mut1g, nuf2114mnt1g, nuf2116mnt1g and nuf420mnt1g of ansenmey semiconductor. These filters are integrated with ESD protection function to protect 2 to 4 audio lines, and the diode capacitance is between tens of PF and 240 PF. Taking nuf2441fc as an example, this LC filter provides EMI filtering and IEC61000-4-2 level 4 ESD protection functions for two audio lines. It is encapsulated by flip chip, and a single IC replaces two inductors, four capacitors and four TVs diodes to help save cost and reduce the occupied space of the circuit board.Nuf2450mut1g is also a two-wire LC type EMI filter and ESD protection device, providing attenuation greater than - 30 dB in the frequency range of 800 MHz to 5.0 GHz; This device uses space saving udfn 1.2 one point eight The 0.5mm ultra small package provides a 20 MHz cut-off frequency and minimal line impedance, which is ideal for audio applications requiring low bandpass attenuation. Nuf2114mnt1g is a two-wire RC type EMI filter and ESD protection device. It is packaged in dfn8 and provides attenuation greater than - 30 dB at the frequency of 900 MHz to 3.0 GHz. It also replaces up to 10 discrete components with a single IC to help reduce cost and save space.In mobile phone applications, the bandwidth of data lines such as display screen and camera is higher than that of audio, and RC filter can be used. For example, ansenmey semiconductor adopts a series of devices such as nuf40xx, nuf60xx and nuf80xx encapsulated by udfn. In addition, ansenmey semiconductor also launched X3 series RC filters in very small wdfn / udfn packages for data line filtering applications, including nuf4310mn and nuf4110mn. This new series of 4-channel RC filters has a line capacitance of only 17 pf at 2.5 V and integrates 40 discrete components to provide a very small footprint (1.0 one point four 0.75 mm/1.0 one point six 0.75 mm), extremely low impedance (100 ) and industry-leading ESD protection (IEC61000-4-2 level 4), supporting up to 120 Mbps bandwidth, suitable for high-resolution camera module and display screen of portable products such as mobile phone, mobile interconnection device (MID), portable media player (PMP), digital camera, laptop or netbook.In the above data applications such as high-resolution display screen of mobile phone and camera interface, high-speed LC filter can also be used, such as nuf2900mn of ansenmey semiconductor. Compared with the traditional RC filter, the high-speed LC filter has higher cut-off frequency, greater broadband attenuation and lower insertion loss. For example, the typical cut-off frequency of nuf2900mn is 350 MHz, which provides attenuation greater than - 30 dB at frequencies from 800 MHz to 6.0 GHz, and the insertion loss performance is also more advantageous. See Figure 4.Figure 4: comparison of response performance between typical RC EMI filter and high-speed LC EMI filter (nuf2900).It is worth mentioning that there are more and more high bandwidth applications in mobile phones, with larger display size, higher resolution and limited space, which promote the conversion of parallel data to serial data. The solution is to use low-voltage differential signaling (LVDS) to serial MDDI, MPPI, USB 2.0 and userdes data, and adopt common mode choke (CMC) EMI / RFI filter accordingly, Through the high bandwidth differential signal, the unwanted common mode EMI / RFI signal is filtered at the same time. In this regard, the nuc2401mn high-speed serial data filter of ansenmey semiconductor can be used. This is the industry's first CMC filter integrating ultra-low capacitance (0.8 PF) ESD protection and common mode filtering technology, using a small 2.0 In 2.2 mm DFN package, a single element is suitable for a variety of high-speed designs such as USB2.0 (480 Mbps), IEEE1394 (400 Mbps), MDDI (up to 550 Mbps), Mipi (up to 1.0 Gbps) and HDMI 1.2 (up to 1.32 Gbps per channel), eliminating common mode noise and providing pure data stream for these applications.Figure 5: integrated CMC filter nuf2401mn with ultra-low Capacitance ESD protection for high-speed applications such as USB2.0.It is worth mentioning that nuc2401mn provides better ESD clamping performance compared with silicon competitive devices with a capacitance of less than 1 PF. It is very suitable for EMI filtering and ESD protection applications of high-speed data lines.summaryWith the improvement of data rate and clock frequency, portable devices such as mobile phones increasingly need high-performance EMI filtering and ESD protection schemes. Ansenmey Semiconductor provides a new integrated EMI filter. While providing excellent EMI / RFI filtering performance, it also provides ESD protection function in accordance with IEC61000-4-2 level 4 standard. A single IC replaces 10 or even dozens of discrete components. It is very suitable for audio and data line applications in portable applications such as mobile phones.Source; Mobile China

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."