How to Make My Computer Display the Screen Full Size?

adjust your screen resolution... if you had adjust it to high and still the same.. get a video card the has a highest resolution.

How to Make My Computer Display the Screen Full Size? 1

1. ???...My laptop display screen needs cleaning...???

there are products available at computer stores, but they mostly are composed of alcohol and other agents, you can safely use Windex and a soft clothes to wipe the screen depending if its glossy or matt, be careful to not scratch the surface with a hard or coarse clothe. spray on the cloth and then wipe, if there are sticky smudge then try to get more windex on it but becaureful you dont get any inside the screen bezel.

2. Utility to display on screen the currently pressed keys

QiPress seems to work for me.There is a lite and a pro version at $30. The lite version is enough for my needs

How to Make My Computer Display the Screen Full Size? 2

3. Laptop display screen won't light up?

the only way that i comprehend to tell for specific if it is the backlight or inverter is to plug a regular solid backlight into the inverter. If it lights then it is the backlight, if no longer it is the inverter. The inverter is a miles less costly, ordinary restoration or it is going to be besides. The backlight section is way less costly yet is complicated (study high priced) to interchange except you pick to aim it your self. It frequently is not the two

4. Why do we call a computer or TV display a "screen?

I discovered a very helpful passage from the book, The Oxford Handbook of Management Information Systems: Critical Perspectives and New Directions(link takes you to the passage)The author notes that the word "screen" originates from the 14th century, andevolved from the Middle English word serene, from the Middle French escren, and from the Middle Dutch scherm. It is a word akin to the Old High German (eighth century) words skirm, which meant shield, and skrank, which meant a barrier of some kind. The word screen also suggests another interesting signification, further away from us in history. It is a word 'probably akin' (MW) to the Sanskrit (1000 BC)" words carman, which meant 'skin', and kn'z'nti, which signifies 'he injures' (MW). These are possible meanings from which the Middle Age words evolved. The Sanskrit clue suggests that the notions of protection, shield, barrier, separation arose, possibly within the older Proto-Indo-European language, as metaphors of the concept of skin-possibly that of human (or animal) skin.So there is a lot to do with protection and barrier which run through the evolution of the word. The author goes on to describe the chronological relations between the words:A barrier or a protection is something raised over and against another something. This 'other' something faces the barrier, as the wind faces the windscreen of a car, which means that the screen protects against something, to be excluded, that moves towards it. That which is moving towards the screen could have been understood as a projection (from the Latin word projectare, which meant 'to throw forward') over a surface-just like the arrows and bullets were projected over the shields, or like the heat is projected onto the fireplace screen. The screen protects and shelters (just as a skin. . . ) because it receives and holds the projection of that which is not to be received 'inside' the cover that the screen provides. But what happens when something stopped by the screen is allowed to pass through? The answer is that it was screened. This means that it was permitted to pass through that barrier, or that it simply passed through it. The screen as a barrier is now understood as a 'system for detecting [for example] disease, ability, attribute' (OPDT 1997: 681-2). This interpretation links, or so we hope, the three central themes of meaning attached to the word screen: hiding/protecting, projecting/showing, and testing/selecting (ibid.).The author goes on to argue that these three themes all have a central intent - a demand for our attention. They provide this table to help show this. P.270I think that should pretty much answer the question. The author has other interesting things to say on the word as well, and explains the phenomenology of the word and relates it to concepts like "the truth in seeing". Interesting stuff!

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Analysis of System Composition and Architecture of LED Display Screen
Analysis of System Composition and Architecture of LED Display Screen
As a high-tech product, LED display has attracted great attention. The intelligent full-color display, which is controlled by computer and integrates light and electricity, has been applied in a wide range of fields. The pixel points adopt LED light-emitting diodes, and many light-emitting diodes are arranged in a dot matrix to form an LED array and then an LED screen. Through different LED driving modes, images with different effects can be obtained. Therefore, the advantages and disadvantages of LED driver chip play an important role in the display quality of LED display screen. LED driver chips can be divided into general chips and special chips.General purpose chips are generally used for low-end products of LED display screens, such as indoor single and dual color screens. The most commonly used general chip is 74HC595, which has the functions of 8-bit latch, serial shift register and three state output. Each channel can output 35mA non constant current at most.Because LED is a current characteristic device, that is, on the premise of saturated conduction, its brightness changes with the change of current, not with the change of voltage at both ends. The biggest feature of the special chip is to provide constant current source output, ensure the stable driving of LED and eliminate the flicker of LED. With the characteristics of high output current and constant current, it is suitable for occasions requiring high current and high image quality, such as outdoor full-color screen, indoor full-color screen, etc.LED driver chip series products for LED display smt5026.smt5026 has built-in CMOS shift register and latch function, which can convert serial input data into parallel output data format.Part II: system architecture of LED display screen(1) Display unitThis is the main part of the LED display screen, which is composed of luminous materials and driving circuits. The indoor screen is the unit display board of various specifications, and the outdoor screen is the unit box.(2) Main controllerThe function is to buffer, transform and reorganize the input RGB digital video signal, and generate various control signals.(3) Switching power supplyThe purpose is to change 220V AC into various DC to supply various circuits.(4) Transmission cableThe display data and various control signals generated by the main controller are transmitted to the screen body by twisted pair cable.(5) Scan controllerThe function of the circuit board is to buffer data and generate various scanning signals and duty cycle gray control signals.(6) Special display card and multimedia card (video card)In addition to the basic functions of the computer display card, the LED full-color display card also outputs digital RGB signals, line, field, blanking and other signals to the main controller. In addition to the above functions, the multimedia card can also change the input analog video signal into digital RGB signal (i.e. video acquisition).(7) Other signal sources and their external devices
With the Rapid Development of Mobile Internet, the Production Qualification Rate of Display Screen I
With the Rapid Development of Mobile Internet, the Production Qualification Rate of Display Screen I
XXX backlight panel manufacturing factoryWith the rapid development of mobile Internet, the software and hardware technology of smart phones have been rapidly improved. At the same time, the price is also developing in the direction of more and more civilians, which makes the development of smart phones in China more and more diversified and the scope of application more and more comprehensive, and plays an extremely important role in people's intelligent life.Mobile phone display screen is an important part of smart phone. The production qualification rate of display screen and the production quality of mobile phone play a very important role in the popularization of mobile phone. Unqualified mark line will lead to product display problems. The traditional mark detection is an artificial naked eye detection method. There is a phenomenon that the detection change range is too large due to the instability of the artificial naked eye, which leads to the problems of inaccurate detection and low efficiency.At present, many types of work requiring precise calculation have been replaced by automation equipment, and the visual inspection of backlight is no exception. Follow the Xiaobian:What problems can be solved?It mainly detects the mark line of the mobile phone backlight, including:Number of mark lines (excessive and missing);Mark line length, accuracy plus or minus 0.1mm;The distance from the mark line to the specified frame, with an accuracy of plus or minus 0.1mm;Camera assemblyDetection processTest effectTake two stations as an exampleTest conclusionFrom the early sample test results, the software can accurately detect the edge of each sample and the mark line on the product, and accurately calculate the length of each mark line, the distance between each mark line and the edge and the number of mark lines. The specific indicators are as follows:(1) Detection accuracy: 0.1mm (compared with the actual product, it is related to the marking and filling method, appearance and measurement benchmark, and there will be corresponding fluctuations)(2) Detection efficiency: it varies according to the number of mark lines, 20 for each piece, and the detection time is within 0.5s;(3) Product model: support multiple models of the same material, with the maximum size of 80 * 160mm.(4) Mark line color: white and black. The detection parameters need to be adjusted.
Aventk UV Color Changing Black Glue 1098 Can Effectively Solve the Reflection Problem of OLED Displa
Aventk UV Color Changing Black Glue 1098 Can Effectively Solve the Reflection Problem of OLED Displa
Reflective problem of OLED display The core of OLED is a transparent organic semiconductor polymer, which can be made into a thin film and emit light by applying an electric field on both sides. Because the structure of OLED panel is very simple in theory, very thin products can be made. At present, the thickness of OLED display screen in mass production is only 0.95mm. Although OLED display is a self luminous product, after removing the backlight, there should be no problem of backlight leakage in theory. However, in terms of actual products, due to the existence of MF coating, there is still a problem of reflection around the edges of the display screen, as shown in the following figure:Therefore, how to solve the reflective problem of OLED display has become a concern of many manufacturers. In this regard, aventk has also studied and tested for many times, and finally determined that aventk 1098 series UV color changing black glue can solve this problem. Aventk UV color changing black glue 1098 can solve the problem. In solving the reflection problem of OLED display screen, most of them used UV black glue before. However, UV black glue needs to take into account UV light irradiation, so the blackness cannot be too deep, otherwise UV light cannot irradiate the cured glue. However, if UV glue black is not enough, it can not achieve good light blocking effect.To solve this problem, aventk 1098 series UV color changing black glue can be solved. Aventk UV color changing black glue contains aventk's exclusive NYX technology. NYX technology is aventk's unique UV light dyeing technology, which perfectly combines UV light with glue dyeing. It is a transparent color before UV curing and can well absorb UV light. After UV curing, it becomes black (or other colors). It not only meets the high efficiency of UV light curing, but also quickly completes the dyeing of glue. Put aventk UV color changing black glue is applied around the OLED display screen and between the screen and pol, which can greatly reduce the problem of reflection. fqj
LED Display Screen Enterprises to Enter the Field of 'price' -Information Industry News
LED Display Screen Enterprises to Enter the Field of 'price' -Information Industry News
Explore what your device can do and how to use it. Always On Display allows you to view the clock, battery and missed phone call/message notifications when the screen is turned off. The Always On Display screen uses less power and also utilizes the proximity sensor to turn off completely when in a purse or pocket. The user can change what appears on the Always On Display screen. Back up and sync your contacts, photos, videos, and more from your device. Bixby Vision gives you a deeper understanding of what you are looking at through your camera by identifying landmarks, translating languages, or showing you where to buy an item. Watch, search, and record your favorite movies and shows, and turn your device into your remote control, with the DIRECTV app on your phone. All of HBO together with new hits, classic favorites, plus new Max Originals. Hello Bixby allows you to quickly set reminders, create voice dictation, search and access content on your phone and on the internet. The Multi Window feature provides split-screen functionality, which allows you to use two applications at the same time. Complete multiple tasks on one screen, take notes while watching a video, or search the web and check your email messages simultaneously. View and pay your AT&T bills online, manage your account, reset passwords, or upgrade your AT&T services.Learn how to find your device and secure your info. Free apps typically get revenue through ads, pop-ups, or notifications. Learn how to manage these on your device. Find My Mobile allows you to manage your device in a secure way by tracking and controlling your device remotely. Secure your personal content and keep it hidden on your device. Lock or unlock your display, set a screen security lock type (pin, password, pattern, fingerprints, or iris and face recognition), get your PUK code, or request your device be unlocked from the ATnT network. Learn how to determine if you might have harmful software (malware) on your device and get tips to help fix the issue.Given current technology, could TV display screens double as video camera sensors?Yes, with interferometry based synthetic aperture imagery, but...It would take several orders of magnitude improvement in digital signal processing technology for it to work at the scale of a video screen. The sensors will need to record at a very high data rate, on the order of petahertz. Every single pixel will be receiving all of the light that is in its field of view, and none of the light will be focused. Fortunately, light is not just photons, it's also electromagnetic waves. The sensors will behave like antennas, rather than eyes, passively collecting the radio waves at the wavelength of visible light.Radio signal sources can be tracked quite easily, by measuring the timing of a wave reaching multiple antennas. The same applies to all sorts of waves; an earthquake's epicenter is calculated by measuring the timing when the waves arrive at seismometers. We even have the same types of sensors built into our own human bodies. : Our ears can taking a wave and determine the direction that it came from, based on changes of intensity and timing. We have already proven the concept using vast antenna arrays to collect unfocused photons, to create a focused image. We imaged the supermassive black hole M87* using the Event Horizon Telescope.Of course, when astronomers use the term "photon" they do not just mean visible light; they mean any coherent electromagnetic wave. This image represents the peak of current engineering feasibility for synthetic aperture imagery. The EHT uses a Very Long Baseline Interferometry, which works in 450 GHz, using very narrowly calibrated equipment designed specifically to tease out the glow of the accretion disk at the wavelengths to detect event horizons around black holes. In order to get meaningful data, though, your sample rate needs to be at least twice the frequency of the signal rate, preferably more than 4 times the signal rate, or you start getting downsampling errors called aliasing. In order to record visible light, which has frequencies between 405 THz to 790 THz, you will need a sample rate that is at least 1.58 PHz.Due to limitations from the speed of light, and the time that it takes electrons to pass through silicon and copper in computers, this is just past the fastest speed that we can record data meaningfully.We would have to pass the data from several sensors in order to build up a meaningful synthetic aperture image from interferometry. We would need specialized recording technology that we just do not have yet.And, there's also the problem that LEDs are not designed to collect light, even though they are capable of doing it. .. just as sound coming out of a microphone would sound terrible, and sound recorded from speakers is also low quality. It would take several generations of iterating on the current science in order to use an LED-based computer monitor to record what is happening it a room, and it will always require specialized systems to just record the data in a meaningful way, much less process it into an image. It took several petabytes of data and 3 years of processing in order to build the EHT's image of M87*. It was faster to hand-carry the hard drives from the telescopes around the world to the datacenter, than it would have been to send the data over high speed internet links. It would take a lot of iterative work to miniaturize the chips necessary to do the calculations, but the technology just barely exists.Such a screen would be prohibitively expensive, as it's much easier to just put a lense in front of a cluster of photodiodes (i. e. , a webcam) and hide that in the corner of the screen, but those leave physical evidence... you can see the lense if you take the screen apart. It could be possible, with non-digital interferometry, to construct such an image of the room in real time. .. but that equipment barely fits in the basements of large telescope observatories, and requires cryogenic cooling. You would not be able to collect it clandestinely, and would be much cheaper (and higher quality) to use a webcam.
What Are the Components of LED Display_ Application Method of LED Display Screen
What Are the Components of LED Display_ Application Method of LED Display Screen
What are the components of LED displayLED display is a flat panel display, which is composed of small LED module panels. It is used to display text, image, video, video signal and other information. The components are as follows:1 LED unit board: it is one of the core components of LED display. The quality of the unit board directly affects the display effect of the display screen. The unit board is composed of LED module, driver chip and PCB circuit board. The LED module is actually composed of many LED light emitting points encapsulated in resin or plastic lattice.2 Connection: it can be divided into data line, transmission line and power line. The data cable is a flat cable used to connect the control card and the LED unit board. The transmission line is used to connect the control card and the computer. The power cord is used to connect the power supply, control card and LED unit board. The copper core diameter of the power cord connecting the unit board shall not be less than 1mm.3 Power supply: the power supply generally uses switching power supply, 220V input and 5V DC output. It should be pointed out that because the LED display screen belongs to precision electronic equipment, switching power supply should be used instead of transformer.4 Control card: we recommend using a low-cost strip screen control card, which can control a 1 / 16 scanned 256x16 point two-color screen and assemble the most cost-effective LED screen. The control card belongs to asynchronous card, that is, the card can save information without power off, and the information stored in it can be displayed without connecting to PC.Application method of LED display screenLED display screen can help a unit to show what they want to say and release some announcements and information, so as to facilitate visitors to understand some basic information of the unit.1. First of all, our equipment has been debugged normally. Turn on the power switch first.2. Open the icon on the computer and enter the operation page, as shown in the figure3. Turn on the switch of LED display screen, as shown in the figure4. Turn on the audio5. The following is the renderingsWonderful reading recommendations:Application place of LED display screen_ Development status and trend of LED displayScanning mode and principle of LED display screen_ What does the P of LED display stand forWhat is the power consumption of LED display_ How to connect LED display screen with mobile phoneHow to change words with U disk for LED display screen_ Steps of importing subtitles with U disk for LEDHow long is the service life of LED display_ Six daily maintenance of LED display
What Aspects Should Be Considered When Selecting LED Display Screen
What Aspects Should Be Considered When Selecting LED Display Screen
Indoor LED screen is favored by advertisers in large hotels and supermarkets because of its good display effect and visual feeling. So what should we pay attention to in the selection of LED display in hotel banquet hall?Generally, in the indoor environment, the screen area will exceed 3 m2. Therefore, in this case, there are three options: ordinary rear projection, DLP (digital liquid crystal rear projection) and LED display.The advantages of ordinary rear projection display screen are small pixels and high definition. The disadvantages are low brightness, small viewing angle and short lens lamp life (only a few thousand hours). DLP has the advantages of small pixel points and high definition. The disadvantage is that it has seam. At present, the minimum seam can reach 1mm. Rear projection and plasma display screens are suitable for close viewing. For indoor LED display, the advantages are high brightness and no seam, while the disadvantages are coarse pixel particles and low definition. At present, the economic model of commercialized indoor full-color LED screen is p5p6, and other models include p3p4p7.62p8. LED display screen is suitable for indoor places with long viewing distance.When selecting LED display in banquet hall, the following aspects can be considered:1 die. Like the outdoor full-color LED screen, it is generally recommended that the LED of the indoor full-color display screen adopt the LED encapsulated by Maipu brilliance, and the tube cores of Japan Riya and Cree of the United States are recommended for high-end products.2. Packaging form. The 3528211010 surface mount package has the advantages of large viewing angle, good luminous consistency and easy automatic welding processing. It is the mainstream product of full-color screen.3 density. Due to the large heating capacity of indoor full-color LED chip and high density of control circuit, the point density of commercial full-color screen can not be very high. The screen models in lianchengfa room include p1.6p22.5p3p4p5, P6, p7.62, P8, etc.4. Driving mode. The driving mode of Maipu Guangcai indoor full-color LED screen is constant current driving and adopts dynamic scanning mode (mainly 1 / 4, 1 / 81 / 16 and other scanning modes).5 refresh rate. Improve the refresh rate, and there is no flicker and tailing when shooting with the camera.Other considerations include the scale and brand, price, purpose, installation location and environment of LED display manufacturers. The above are some suggestions on the selection of LED display in hotel banquet hall.fqj
Application and Technical Index of LED Full Color Display Screen
Application and Technical Index of LED Full Color Display Screen
Since this year, the market demand for LED full-color large screen has shown a rapid upward trend. Just after the Spring Festival, large projects began bidding. In April and may, despite the impact of SARS, it only delayed the implementation plan, not cancelled the project. After SARS, many projects have been stepped up. The contract amount of major LED large screen manufacturers increased by 20% compared with the same period last year, and some even almost doubled compared with last year. There are many new companies entering the field of full-color large screen, and their achievements are also excellent. Compared with previous years, the market sprouted early this year, with many large projects, and more than a dozen projects with more than 10 million yuan have been implemented. In the third quarter, many major projects entered the bidding stage. Another feature is the significant increase in projects invested by enterprises, including applications in commercial advertising. It can be said that led large screen, as a commercial advertising media, has been favored by the advertising industry again after nearly ten years of silence. At the same time, the export situation of full-color screens is also encouraging. In early September, the annual optical Expo was held in Shenzhen. This exhibition is a big exhibition of LED industry in the past year. LED large screen, LED lighting, LED traffic lights, LED production equipment, testing equipment and other dazzling, indicating that the new climax of China's LED industry has come. The author believes that this exhibition is a sign that China's LED industry has reached a turning point of localization. Internationally renowned LED light-emitting tube manufacturers and screen manufacturers have also begun to transfer to mainland China on a large scale. Mainland China will become the manufacturer of LED and its productsManufacturing center. Broad market, good investment environment and low labor cost make China gradually become the manufacturing center of the world's electronic industry. Just like computers, mobile phones, televisions and other electronic products, China is also the manufacturing center of LED large screen industry.As a scientific and technological worker who has been engaged in the research and development of LED large screen for a long time, the author has always paid attention to the development of LED large screen in China and the new achievements of international large screen display industry. Three years ago, in the article on the development of LED large screen, the author talked about several application fields and characteristics of LED large screen in China, and proposed that full-color large screen is mainly an image project in China. It should be said that this general pattern has not changed, but the increasing demand for commercial advertising is also a very important development trend. It can be said that China's LED full-color large screen industry is ushering in a new climax. Seriously studying the new situation of market development and technological progress, taking correct countermeasures, seizing opportunities, rapid improvement and sustainable development should be worthy of study by peers. Here, I venture to raise questions about technical indicators and hope that peers and experts will correct me.Image engineering: Aiming at the international first-class level. Image engineering means that the main purpose of building a large screen is to add style to the city or a major event. It does not directly create economic benefits, but it can enhance the city's popularity, shape the city's image, improve the investment environment and create a business atmosphere, which is conducive to economic development and good social benefits, so as to indirectly create economic benefits. Image engineering is mainly government investment, focusing on social benefits, rather than or mainly obtaining economic benefits through commercial operation. In recent years, the large LED screen of large squares in urban central areas or citizen leisure squares built in many parts of the country is a typical image project. A large number of LED displays in stadiums and gymnasiums are necessary supporting facilities for modern stadiums and gymnasiums, which also belong to this category.Since it is an image project, it is bound to pursue the perfect performance and effect as much as possible, especially high-quality video images. Generally speaking, it is to make a giant color TV, which has been worked hard by many domestic manufacturers for a long time, and has made considerable progress, but it is still far from our ideal goal, and there is still a big gap compared with foreign full-color large screens.At the beginning of this year, the commercial street of Hunan Road in Nanjing invested heavily in the construction of a full-color large screen with an area of 114 square meters. The screen was built by UNITEK company in the UK and has been running for more than half a year. From the effect, it can be called the best large screen in China. The author participated in the formulation of the technical indicators of the screen and the final acceptance test, and felt that many aspects were worthy of learning and imitation by domestic peers.As a large full-color screen, its key technical indicators include: high enough brightness, viewing distance and viewing angle; Good color reduction; Sufficiently high grayscale capability; High enough scan refresh rate. High enough video signal processing capability, especially good consistency, structure and technology. The technical indicators set by Hunan Road Daping during bidding are:The white balance brightness is greater than 5000 CD / m2;White balance color temperature 6500k;The number of video processing bits is greater than 10bit;The gray level of each primary color is greater than 10bit, which can display 1.07 billion colors;Refresh frequency is greater than 400Hz;The display screen has no perceptible color difference, and the color difference of each primary color of the full screen is less than 4nm;There is no perceptible brightness difference on the display screen, and the brightness difference of adjacent pixels is less than 5%. There is no perceptible mosaic when displaying monochrome gray images of red, green and blue;MTBF is greater than 5000 hours and MTTR is less than 30 minutes;Objectively speaking, not only at that time, but also today, the products of domestic manufacturers have not been fully achieved. In many cases, due to the improvement of the level of LED, the brightness of the normally designed large screen is no longer a problem and can meet the requirements. However, brightness is only an important indicator, not all. Now we generally feel that the large screen brightness of domestic manufacturers is more than enough and the softness is insufficient. The overall effect is not as good as that of foreign well-known manufacturers. The reason is that there are more technical problems that have not been solved. The author believes that from a technical point of view, it is necessary to make efforts in the following aspects.(1) Color matching and blendingThe large screen is composed of a large number of light-emitting diodes. The photoelectric parameters of the light-emitting diodes must be designed, calculated and tested in order to achieve a good white balance. Simple estimation and judgment with the naked eye can not have good results. This involves the selection and driving design of LED, which not only affects the photoelectric performance of the screen, but also affects the reliability. Especially in the design of indoor full-color screen, thermal design should be paid enough attention, otherwise the effect and reliability will be a problem.
System Design of LED Display Screen
System Design of LED Display Screen
With the rapid development of science and technology, the development of traditional TV, newspaper and magazine media has lagged behind the development of outdoor media. Here we will introduce the system design of dot matrix LED dot matrix display.Composition of LED dot matrix displayComposition of LED dot matrix display: it is a new display device, which is composed of multiple LED's encapsulated together. In order to explain the principle of LED dot matrix display, a display system including hardware and software is designed and manufactured with single chip microcomputer as the control core. The circuit can realize various display forms such as rolling shutter, moving up and moving left of any number of Chinese characters through key control. It can be widely used in public places such as airports, shopping malls and hospitals for text advertising and information release. Moreover, it has the characteristics of small volume, simple circuit structure and easy implementation.LED dot matrix displaySystem hardware circuitThe hardware circuit of the display controller is mainly composed of three parts: serial communication interface, expansion of external memory, LED dot matrix display driver and interface circuit. Generally speaking, there are many contents to be displayed, so the external data memory must be expanded. Static data memory has the advantages of low cost, low power consumption and fast reading and writing speed. We use two pieces of static ram62256 data memory (64KB in total). Store all the content codes to be displayed in 62256.System software programSoftware program is the core of the whole control system. After the system main program starts, the system environment is initialized first, including setting serial port, timer, interrupt and port. The whole software design is mainly divided into two parts: display part and communication part.Communication part: the upper computer software adopts visual basic programming, and VB is used to provide a powerful communication control MSComm, which controls the message format and protocol setting of serial port and serial port communication, and directly uses the serial port of PC to send data. In order to realize the reliable communication between MCU and PC, both sides must have the same data format and baud rate. The use of the software is relatively simple. When using, you can use Microsoft Word to handle the content to be displayed (note that the width of the page setting should be the same as that of the LED dot matrix display), then select the select all command and copy command in the edit menu, and then run the LED display Download Software v1.1. Select the "clipboard" button in the interface, and the content to be downloaded can be displayed in the preview box, After checking, select the baud rate and connect to the serial port, click the "download" button, and you can download the display. Repeat the above operation when you need to modify or display new content. It is very convenient to use.Display part: use dynamic scanning to realize the control and display functions of Chinese characters, characters, images and data transmission on the display screen. The program divides the data memory into three areas: display buffer, data storage area and receiving buffer. The single chip microcomputer receives the data from the PC through the serial port interrupt, temporarily stores it in the receiving buffer, analyzes and processes it, saves it in the data storage area according to certain rules, and then extracts the data from the data in the memory according to the display mode sequence to display it in the display buffer. The display adopts progressive scanning. The real-time communication part of PC mainly uses the MCU serial port to interrupt the reception of data information and realize the data information transmission with the computer.
Composition and Working Principle of LED Display Screen
Composition and Working Principle of LED Display Screen
In this paper, LED display screen is composed of several display units (unit display board or unit display box) that can be combined and spliced, plus a set of appropriate controller (main control board or control system). Therefore, a variety of display boards (or unit boxes) with different control technologies can form many kinds of LED displays to meet the needs of different environments and display requirements.1 Main composition of LED display screen (taking the more complex synchronous full-color screen as an example)1. The metal structure frame is used to form an inner frame and carry various circuit boards such as display unit board or module and switching power supply2. Display unit: it is the main part of LED display screen, which is composed of LED lamp and driving circuit. The indoor screen is the unit display board of various specifications, and the outdoor screen is the module box.3. Scanning control board: the function of the circuit board is data buffer to generate various scanning signals and duty cycle gray control signals.4. Switching power supply: change 220V AC into various DC to supply various circuits.5. Transmission cable: the display data and various control signals generated by the main controller are transmitted to the screen body by twisted pair cable.6. Main controller: buffer the input RGB digital video signal, transform the gray level, reorganize it, and generate various control signals.7. Special display card and multimedia card: in addition to the basic functions of computer display card, it also outputs digital RGB signals and line, field, blanking and other signals to the main controller. In addition to the above functions, multimedia can also change the input analog video signal into digital RGB signal (i.e. video acquisition).8. Computer and its peripheralsFigure 1 LED display system composition2 Analysis of main functional modules1. Video broadcastThrough multimedia video control technology and VGA synchronization technology, various forms of video information sources can be easily introduced into the computer network system, such as radio and satellite TV signals, camera video signals, VCD video signals of video recorders, computer animation information, etc. Therefore, the following functions can be realized:Support VGA display and display various computer information, graphics and images.Support various input modes; Support pal, NTSC and other systems.Display color video images in real time to realize on-site broadcasting.Broadcast radio and television, satellite television and cable television signals.Real time playback of video signals such as TV, camera and video disc (VCR, VCD, DVD and LD).It has the function of playing pictures and words with different proportions on the left and right at the same time2. Computer broadcastGraphic stunt display function: it has the functions of editing, zooming, flowing and animation.Display various computer information, graphics, images and 2D and 3D computer animation and overlay text.The broadcasting system is equipped with multimedia software, which can flexibly input and broadcast a variety of information.There are a variety of Chinese fonts and fonts to choose from. At the same time, you can also input English, Spanish, French, German, Greek, Russian, Japanese and other languages.There are many broadcast modes, such as single / multiple line translation, single / multiple line up / down, left / right pull, up / down, rotation, stepless zoom, etc.Editing, broadcasting and instant release of notices, announcements, announcements and news, and there are a variety of fonts to choose from.3. Network functionEquipped with standard network interface, it can be connected with other standard networks (information query system, Municipal Publicity network system, etc.).Collect and broadcast real-time data of each database to realize remote network control.You can access the Internet through the network systemIt has a sound interface, which can be connected to audio equipment to achieve audio-visual synchronization.4. Screen controllerThe screen controller controls the display effect of its corresponding display screen. It can automatically run a continuous cycle program to obtain relevant display data according to the given program list, or it can intervene manually to produce the display effect on the screen. The pixels on the screen are directly mapped with the pixels on the corresponding area of the screen controller display.The screen controller can manually adjust the brightness of the display screen and select the gray nonlinear correction data suitable for the current environment. The screen controller can also automatically adjust the brightness of the display screen and select different gray nonlinear correction data according to the ambient brightness through the network system.The contrast and chroma of image display can be adjusted through the screen control machine. The screen controller transmits the information to be displayed to the video processing and control unit for video processing.5. Video processing and control unitThe video processing and control unit completes the image processing of the display data, including:The second level of gray nonlinear correction can be adjusted automatically or manually.Automatic or manual stepless brightness adjustment.The gray level control system can control the display screen to display 24 bit data of 8 bits of each primary color, that is, 256 gray levels of each primary color.Image noise reduction processing to ensure that the image is cleaner and smoother.Image enhancement technology, image edge enhancement technology.Motion compensation technology, chroma adjustment function.6. Visual processingIn the system, the brightness of each primary color of a single module can be adjusted respectively, the color balance can be adjusted, and the mosaic phenomenon can be basically eliminated. The brightness consistency of all modules and display modules is good, and the monochrome display has no visual difference.The video processing and control unit transmits the processed display information to the communication module for long-distance transmission to the display screen.7. Communication moduleThe communication module ensures that the display content of the screen control machine is accurately transmitted to the display screen for a long distance. The communication module encodes and decodes the transmitted information, and processes the long-distance transmission and reception data. The communication module transmits the display information to the data distribution and scanning unit.The LED display screen is usually composed of the main controller, the scanning board, the display control unit and the LED display screen body. The main controller obtains the color brightness data of each pixel of a screen from the computer display card, and then assigns it to several scanning boards. Each scanning board is responsible for controlling the dry lines (columns) on the LED display screen, and each line (column) The LED display signal on the is transmitted in series through each display control unit of the bank, and each display control unit directly faces the LED display body. The work of the main controller is to convert the signal of the computer display card into the data and control signal format required by the LED display screen. The function of display control unit operation is similar to that of image display screen. It is generally composed of shift register latch with gray level control function. However, the scale of video LED display is often larger, so we should use integrated circuits with larger integration scale. The function of the scanning plate is the so-called connecting link. On the one hand, it receives the video signal of the main controller, on the other hand, it transmits the data belonging to the current level to its own display control units, and also transmits the data not belonging to the current level to the next cascade scanning plate. The differences between video signals and LED display data in space, time, sequence and other aspects need to be coordinated by a scanning board.
These Four Factors Need to Be Considered in the Design Scheme of Stage LED Display Screen
These Four Factors Need to Be Considered in the Design Scheme of Stage LED Display Screen
Before the implementation of the stage rental LED display screen project, it is necessary to make a design scheme, especially when designing the screen body, it is necessary to consider important factors such as the display screen model, display content, installation site environment and cost, and ensure that the production process and technical indicators are suitable for the actual indoor application needs, so as to carry out reasonable design.The sense of visual graininess mainly comes from the fact that the human eye has a certain resolution. When the two points are close to a certain extent, the human eye will not be able to distinguish them. In recent two years, with the improvement of LED display manufacturing technology and the continuous improvement of small spacing LED display body resolution, the indoor display design has been improved from the initial selection of the minimum point distance specification scheme to the selection of the appropriate point distance specification scheme.Pixel spacing is the distance between lamp beads, for example, P3 pixel spacing is 3mm; The minimum sight distance is the distance that human eyes can't distinguish pixel particles, but this distance will damage vision if viewed for a long time; The best viewing distance is not only the comfortable distance to watch the screen, but also the clearest distance; The pixel density is the screen definition index. The larger the value, the higher the screen definition; Full HD image and video, screen 16:9 golden ratio, human vision is the best.According to the analysis in the above table, the rental LED display screens of p1.27, p1.54, P1.6, p1.9 and p2.5 are small spacing LED display screens (the point spacing is less than 2.5mm). The minimum viewing distance and the best viewing distance are very close to the viewing requirements of large flat panel TV, and the whole screen resolution is up to 4800 2400, clearer pictures can be displayed on the same screen body, but one HD signal needs to be amplified by 3 4 times on a 12m wide screen, and two HD pictures need to be amplified by 2 times; At the same time, high-resolution display requires high-performance image processing equipment, and the overall cost of the system will be very high.P4 and p4.8 cannot display two high-definition pictures at the same time on a 12m wide screen, which can not meet the display requirements of high-definition conference TV pictures. P3 can meet the requirements of displaying two high-definition pictures at the same time. According to the size of the display screen, P3 with high cost performance is finally selected as the display point distance of the main screen and auxiliary screen of the project, and P4 is selected as the display point distance of the monogram screen.One factor that determines the quality of LED is the main materials, such as chip, bracket, glue (epoxy resin), gold wire, etc. the other factor is the packaging process. Pixel packaging technology is related to the color saturation, viewing angle and other display effects of the whole display screen, production cost and quality stability. It is one of the key indicators for selecting LED display screen.The mainstream indoor LED packaging technologies mainly include in-line dip and SMD mode. The in-line module encapsulates the light-emitting tube into a square shape, and then puts the red, green and blue tubes together to make a pixel module, which is directly inserted and welded on the PCB board. The process is relatively simple, the cost is low and the defect rate is high. It is mainly used in outdoor display screens. Surface pasting refers to pasting the encapsulated light-emitting tube on the circuit board, and then processing the integrated circuit welding process into a screen body. It has good heat dissipation and uniform color, and the whole display screen can be maintained in the front, which greatly reduces the maintenance cost and difficulty; At the same time, metal compounds are filled in the packaging process, which has good color mixing effect and soft luminescence, and is more suitable for indoor application.Three in one surface sticker refers to that three light-emitting points of red, green and blue are encapsulated and synthesized in the same light-emitting tube. When you look closer, it is a point. When you zoom in, it is a line separated from the three light-emitting points. It has high requirements for materials and processes in the production process. It is mainly used for the production of high-end LED displays with small spacing and high density.Three in one surface sticker (separate surface sticker) refers to that the three light-emitting points of red, green and blue are packaged separately. After packaging, they are arranged into one pixel point, and then packaged with a mask for protection, which can prevent dust and scratch, and protect the light-emitting chip. Three in one is the separation of table stickers, three-point separate power supply, low power consumption, single lamp maintenance and low cost.Generally speaking, in order to improve the display effect of indoor screen, three in one surface paste, black light technology, gold wire packaging, etc. are selected.The LED control part is the core part to determine the display effect. The control circuit has a high-performance single-chip micro control chip. The controller sends the control signal and data to the LED driver chip through the internal control program. After receiving the signal, the LED driver chip generates the corresponding action, so as to realize the independent control of each red, green and blue LED light-emitting chip.1. Drive systemThe function of the LED driving part is to receive color data and drive the LED display screen to display according to the brightness value represented by the data. There are usually three modes: constant current, voltage stabilization and constant voltage constant current.The output current of the constant current drive circuit is constant, and the output DC voltage changes with the change of load resistance. The whole circuit is not afraid of load short circuit, but it is strictly prohibited to open the load completely. The voltage stabilizing circuit outputs a fixed voltage, and the output current changes with the increase or decrease of the load. The whole circuit is not afraid of open circuit of the load, but it is strictly prohibited to completely short circuit the load. The first constant voltage and then constant current mode is the most ideal driving circuit. It not only detects the LED current, but also controls the LED voltage, which is conducive to improving the LED life and reducing the power consumption. It is generally used in high-grade LED products.2. Control systemThe display effect of stage LED display screen depends on the size and time of current and voltage through it, so the control system mainly controls the power output of LED. At present, the LED power supply designed by PWM (pulse modulation) control mode has a conversion efficiency of 80% 90%, and the output voltage or current is very stable. It is a high reliability power supply.PWM can control the time ratio of LED on and off. By dividing the time ratio into several levels, the LED displays a corresponding number of gray levels (gray scales). The product of the gray level of the three primary colors is the number of colors that can be reproduced on the display screen in theory, which is generally 256 levels. When the number of colors reaches 16.7M, 24 bit true color information can be displayed.Generally, the frequency of PWM is greater than 100Hz, otherwise there will be flashing and scanning lines when watching. At present, the gray level of Wittem indoor rental screen is 14 bits and above, the refresh frequency is 1920hz and above, and the highest refresh rate in the LED industry is 6800hz. Under the normal viewfinder and rotation of the camera, the LED screen display is stable without flicker, and the gray scale is too smooth at the highest refresh rate without color mixing.3. Combination of drive system and control systemAs the load of the circuit, the connection between LED and the circuit of driving system and control system is related to the stability of the whole display screen. Generally, there are three modes: series, parallel and hybrid. Series connection is a connection method with low reliability, which is often used in low-end products. In the voltage stabilizing driving circuit, when a LED is short circuited, the voltage distributed to other LEDs will rise, which is easy to cause more damage.The parallel mode is applicable to products with low power supply voltage. In the constant current drive circuit, when one LED is disconnected, the current distributed to other LEDs will increase, which is easy to damage all LEDs in the circuit.At present, in order to improve the reliability of products, the mixed connection mode is generally adopted. The number of series and parallel LEDs is evenly distributed, grouped and connected in parallel, and then each group is connected in series. In this way, the voltage distributed on a series of LEDs is the same, the current through each LED is basically the same, and the LED brightness is the same. At the same time, it is best to add LED temperature negative feedback in the constant current output to prevent the LED temperature from being too high.The whole display screen is spliced by multiple module units. In order to ensure the reliability of power supply and data, hybrid connection must also be adopted to realize the loop backup function. When an abnormal fault occurs in one power supply, other power supplies will automatically conduct intelligent current sharing, so as not to affect the normal use of the system and more effectively improve the fault-free operation time of the system, Reduce failure maintenance time.4 Special requirements for screen body of stage cameraAlthough the high refresh rate can ensure that even under the shooting of high-speed camera, the large screen can still respond in time, and the picture conversion and transition are smoother and smoother; However, in the process of use, it will be found that when the camera lens is aimed at the LED display screen, inexplicable water wave like stripes and strange colors occasionally appear, and the water wave will change with the change of shooting angle and the adjustment of camera lens focal length, which will affect the display effect of live broadcast and recording, This is the moire phenomenon brought about by the digitization of TV camera.If the spatial frequency of the CCD (or CMOS) pixel of the photosensitive element is close to the spatial frequency of the (LED) stripe in the image, a molar stripe will be generated. Since the moire phenomenon is caused by the inherent structure of LED display screen, if one of the conditions for the generation of Moire - the grid structure of LED display screen or the grid structure of camera CCD (CMOS) disappears, the moire interference can be completely eliminated in theory.Domestic companies superimpose a layer of optical processing screen on the surface of LED display screen, which is composed of specific proportion of special light absorbing material and surface bead lens coating. Through the use of optical screen, the LED screen changes from grid light to continuous surface light. Through the amplification and display of discrete LED pixels, a continuous high-definition image is finally formed on the surface of optical processing screen, While improving the contrast, it retains high definition and eliminates the moire phenomenon.
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