First: What is the led display?
LED display (LED panel): LED is light emitting diode, light emitting diodes in abbreviation, abbreviated LED. It is a semiconductor light-emitting diode by controlling the display of its appearance is probably many months from the little red light is usually formed by the bright lights off to show character. Used to display text, graphics, images, animations, quotes, video, video signals and other information on the display screen.
Graphic display and LED display into the video display by the LED matrix blocks. Graphic displays can be synchronized with the computer display Chinese characters, English text and graphics; video display using micro computer control, graphic, image, and Mao, real-time, synchronization,,10.4 Inch Touch Screen LCD Monitor clear message to the broadcast transmission of various information, but also shows two dimensional, three-dimensional animation, video, TV, VCD programs and live on. LED display shows the screen brightly colored, three-dimensional sense of strong, static, such as painting, moving as the film is widely used in finance, tax, business, telecommunications, sports, advertising, industrial enterprises, transport, education systems, stations, docks, airports, shopping malls, hospitals, hotels, banks, securities markets, construction market, auction houses, industrial enterprises in management and other public places.
LED display can show changes in the numbers, text, graphics and video; not only can be used in the indoor environment can also be used for outdoor environment, with a projector, TV wall, LCD screen can not match advantage.
LED reason attention has been attached and rapid development, is that it itself has the advantage inseparable. To sum up these advantages are: high brightness, low voltage, power consumption, small size, long life, impact resistance and stable performance. LED's development prospect is extremely broad, the current is moving in a higher brightness, higher weather resistance, higher luminous density, higher luminous uniformity, reliability, full color of direction.
Second: LED display Category:
1, color by color can be divided into
Single-color display: Single color (red or green).
Two-color display: red and green dual-color, 256 gray scale levels, can display 65,536 colors.
Full-color screen: red, green, blue color, 256 grayscale full color display can display more than 16 million kinds of colors.
2, according to display device classification
LED digital display: seven segment display devices for the digital control code, suitable for production of the clock screen, the interest rate screens, showing the number of electronic display.
LED dot-matrix graphic display: display device is arranged by a number of uniform composition of the dot-matrix LED display modules, suitable for broadcast text, image information.
LED video display: display devices are composed of many light-emitting diodes that can display video, animation and other video files.
3, by using the occasion categories
Indoor Display: LED spots smaller, general Φ3mm - Φ8mm, shows the general area of a few to more than ten square meters.
Outdoor Display: dozens of square meters in size to several hundred square meters, high brightness, can work in the sun, with wind, rain, water resistant.
4, classified by light spot diameter
Indoor screen: Φ3mm, Φ3.75mm, Φ5mm,
Room external screen: Φ10mm, Φ12mm, Φ16mm, Φ19mm, Φ20mm, Φ21mm, Φ22mm, Φ26mm
Room external screen as the basic unit of light emitting tube, LED tube principle is a set of red, green, and blue light-emitting diode sealed in a plastic barrel and jointly develop
5. Display a static, horizontal scroll, vertical scroll and flip display. One block module control drive 12 (up to control 24) 8X8 Dot Matrix, a total of 16X48 dot matrix (or 32X48 dot matrix), is a single block of MAX7219 (or PS7219, HD7279, ZLG7289 and 8279, and the like LED display driver module) 12 times (or 24 times)! Can use "cascade" approach the composition of any large dot matrix display. Effects, good power consumption, and the MAX7219 circuit than the use of lower cost.
The technological advantages of the third led display Review:
Existing common indoor full color program comparison:
1. Dot-matrix program modules: the first design, the interior pseudo-color dot-matrix screen developed from
Advantages: The most advantageous raw material costs and production and processing process is simple, stable quality.
Cons: poor color consistency, mosaic phenomena more serious, show less effective.
2. Single-lamp program: To solve the problem matrix color screen, drawing a program of outdoor display technology, while outside the pixel multiplexing (also known as pixel-sharing technology, virtual pixel) ported to the interior display.
Advantages: color consistency better than dot-matrix module approach.
Disadvantages: blending effect of poor little perspective, about watching a horizontal color. Processing more complex and demanding anti-static. The actual pixel resolution is more difficult to achieve 10,000 points or more.
3. Patch program: SMD LED used to show the program components.
Advantages: Color consistency, perspective and other important indicators show the best of existing programs in a particular three in one surface-mount mixing effect is very good.
Disadvantages: trouble processing costs are too high.
4. Sub-surface mount options: single-light program is actually an improvement, is still under improvement.
Advantage: the display color consistency, perspective and other programs the primary target and stickers little difference, but the lower cost, display good resolution in theory can do more than 17,200.
Disadvantages: Processing is more complex and demanding anti-static.
Fourth: LED display key technical indicators:
Pixels out of control rate
Pixels out of control rate refers to the smallest screen imaging units (pixels) does not work correctly (control) proportion. The pixel control has two modes: one blind spot, that is, blind spots, in the time it does not need bright light, called blind spots; second, often highlight the need but does not shine when it has been lit, called the regular highlights. In general, the composition of pixels have 2R1G1B (2 颗 red light, a green and a blue light, following the same reason), 1R1G1B, 2R1G, 3R6G so out of control is generally not the same pixel in the red, green, and blue light while all the out of control, in which a lamp out of control as long as we believe that this pixel is out of control. For simplicity
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we have by the color LED display (red, green, blue) pixels, respectively out of control and calculation of statistics, which take the maximum out of control as the display pixel rate.
The number of pixels out of control accounted for the total number of full-screen pixel ratio, which we call "full-screen pixel out of control rate." Moreover, to avoid loss of control of any one pixel region, we proposed "regional pixels out of control rate", that is, 100 × 100 pixels in the region, out of control the number of pixels and the total pixel area (ie 10,000) of the same. The index of the "LED display general specification" SJ/T11141-2003 in "out of control pixels were discrete distribution" requirements were quantified, convenient and intuitive.
Currently the LED display in the factory will be aging (roast machine), the LED lights on the control pixels are maintained or changed, "the entire screen pixels out of control rate" control in the 1 / 104 s, the "regional pixels out of control rate" control 3 / 104 is no problem within, and even some corporate standards of individual manufacturers before delivery does not allow out of control pixels, but this is bound to increase the manufacturer's manufacturing and maintenance costs and extend the shipping time. In different applications, the pixel control the rate of actual requirements can have great differences,10.4 Inch TFT LCD Touch Screen Monitor in general, LED display for video playback, the indicator control in 1 / 104 is acceptable within, is to be achieved; If the characters for simple information dissemination, the indicator control is reasonable within 12/104
Gray Scale
Gray is the so-called color scale or gray scale, is the degree of brightness of light and shade. The digital display technology, the gray is the determinant of the number of display colors. Generally speaking, the higher the gray, richer color display screen and the more delicate, more details of the performance of the rich.
Gray level depends on the system's A / D converter bits. Of course the system of video processing chips, memory, and the median transmission system must provide the appropriate support Caixing. Currently the main uses 8-bit LED display processing system, namely 256 (28) gray scales. Simple to understand that from a total of 256 black to white brightness variations. Using RGB primary colors constitute a 256 × 256 × 256 = 16777216 colors. Known as 16 trillion colors. Major international brands with 10-bit display processing system, that is 1024 gray scale, RGB color RGB constitute 1.07 billion.
Although the number of gray color determinants of the decision, but bigger is better not to say unlimited. Because the first resolution of the human eye is limited, Moreover the system will involve dealing with the improvement of the median to the system video processing, storage, transmission, scanning and other links of change, the cost of sharp increases in cost reduction rather than. General civil or commercial grade products can be 8-bit systems, broadcast-level products in a 10-bit systems.
Differential brightness level
Brightness level is the identification of the human eye to distinguish the image from the black to the brightness level between the most white. Mentioned earlier, the gray scale of some very high, can reach 256 or even 1024. However, due to the sensitivity of brightness the human eye is limited, and can not identify these gray levels. That is probably many neighboring gray level is the same as the human eye looks. And the resolving power of each eye varies. For the display, identify the level of the human eye is naturally the more the better, because the displayed image, after all, be looked at. The brightness of the human eye can distinguish more levels means greater display color space, indicating the greater potential for rich color. Brightness level can identify specific software to test, generally up to 20 or more screens to even better levels of.
Gray nonlinear transformation
Gray is the gray nonlinear transformation of data in accordance with the empirical data or a non-linear relationship between the arithmetic transform and then provided to the screen display. As the LED is a linear device, with the traditional display of non-linear display characteristics of different. In order to make LED display can meet the traditional data sources without loss of gray level, usually in the LED display system will do after the gray-level data, the nonlinear transformation, the transformed data the median increase (to ensure no loss of gray degree of data). Internal control systems are now a number of suppliers so-called gray or 16 384 4096 or later are gray through nonlinear transformation that gray space. 4096 is used 8-bit source to 12-bit nonlinear transform space, 16,384 is the use of 8-16 nonlinear transform. By the 8-bit source as nonlinear transformation, the transformed space is certainly higher than 8-bit source large. Usually at least 10. As gray as this parameter is not bigger is better, generally 12 to do enough to change the.
Fifth: LED display commonly used terms explained
1, LED brightness
Brightness LEDs with luminous intensity of the general (Luminous Intensity) that the unit is the candela cd; 1000ucd (micro candela) = 1 mcd (cents Candela), 1000mcd = 1 cd. Indoor Single LED's light intensity is generally 500ucd-50 mcd, and outdoor LED single light intensity is only general should be 100 mcd-1000 mcd, 1000 mcd or more.
2, LED pixel module
LED arranged in matrix or document segment into a standard-size prefabricated modules. Common indoor display 8 * 8 pixel blocks, 8 characters 7 digital module. Outdoor display pixel module has 4 * 4,8 * 8,8 * 16 pixels and other specifications. Outdoor display with pixel blocks because each pixel formed by the two or more LED tubes, solid tubes, also known as the module for the set.
3 pixels (Pixel) and pixel diameter
LED display for each can be individually controlled LED light unit (point) is called pixels (or pixel). ∮ pixel diameter is the diameter of each pixel, the unit is mm.
For indoor display, usually one for a single LED, form a circle. Common indoor display pixel diameter schools have ∮ 3.0, ∮ 3.75, ∮ 5.0, ∮ 8.0, of which the ∮ 5.0 ∮ 3.75 and up.
In the outdoor environment, to enhance brightness, increase the line of sight, a pixel contains two or more cluster LED; as two or more cluster LED generally not circular, solid outdoor display pixels with 22 pixels in diameter generally average distance that : □ 10, □ 11.5, □ 16, □ 22, □ 25.
4, point spacing, pixel density and information content
LED display 22 pixels from the center or point spacing (Dot Pitch); unit area, the number of pixels called pixel density; unit area, called the number contained in the information display capacity. This is the essence of the three described the same concept: the point spacing is 22 pixels to reflect the distance between the pixel density and pixel density of the distance between the physical properties of the display; information capacity is the pixel density of the information carrying capacity the number of units.
The smaller the distance between points, the higher pixel density, the more information capacity, for closer viewing distance.
Points, the greater the spacing, the lower pixel density, the less information content, the farther the distance for viewing.
5, resolution
LED pixel screen ranks as the number of LED display resolution. Pixel display resolution is the total, which determines the information capacity of a display.
6, LED display (LED Panel)
The LED pixel module assembly arranged in accordance with the actual needs of the size of matrix, together with the dedicated display driver circuit, DC power supply, software, frameworks and external decoration, which constitutes a LED display.
7, gray
Light gray is the pixel brightness level change, a color of gray are generally from 8 to 1024. For example, if each color of gray for the 256, for two-color color screen, the display colors for the 256 × 256 = 64K colors, also known as the screen display to 256 colors.
8, two-color
Today most of the color LED display is a two-color color screen, that is, each pixel has two LED dice: one red die, a die for the green light. Die red light when the pixel is red, bright green die when the pixels are green, red and green light when you die while the pixel yellow. In which red, green as color.
9, full-color
Two-color plus red, green and blue color, three color constitute full color. Constitute a full-color as the blue tube and pure green die more expensive, so far, a relatively small color screen.
Sixth: led display market outlook
Status: led display due expensive now, mainly used in more upscale places, mainly in the bustling city sites as part of multi-media advertising. Single color led display are mainly used in transport, highways, banks, securities trading and other financial establishments.
After: With the improvement of living standard, outdoor led display will gradually be used in various industries.
VII of the advantages of LED display technology
(1) imported LED die production of high-quality full-color display: a large angle, low power consumption, uniform color, thickness of ultra-thin screen, screen light weight, low failure rate, easy maintenance advantage.
(2) The PCTV card: The card 10.4 Inch Touch screen Monitoris an excellent set of performance show, acquisition, video capture features such as multimedia video card, the card comes with a Studio editing software. Studio is a company Pinnacle Systems award-winning software common with existing ordinary compared Multimedia Card
It has the following advantages:
① enables the user to their PC, making digital movies, capture video, edit and add the style of the title change, or even their own music and digital video production of narrative.
② Studio allows users to choose to MPEG or AVI file format to store the output video and CD disc, or Web site display, or create video email. As Pinnacle Systems Studio can capture the company's range of devices to work Video capture has become not easy before.
③ Studio applications are from like a VCR is easy to use with good, better, best quality format, and calculate how much the computer can store the video. Studio automatically find and record the scene changes so that editing becomes easy
④ use Studio to create a fast and interactive process. Use instant preview window can be edited at any time preview of the film, that is, one can see that income.
⑤ If you do not like the title or effect, you can make a change and you can immediately see this change, video editing has never been this fast and fun. Enough freedom and enough individual, also has background music, voice-over and other effects.
(3) using the latest DVI interface technology: DVI Interface (Digital Visual Interface) is a PC, and digital flat panel displays (including) the industry standard interface, we all know, 10.4 Inch Touch Screen LCD
the computer is digital, that it dealt with all digital information , but so far the most widely used CRT monitors (such as TV) is analog. So in dealing with good data sent to the computer display, you must be a D / A converter (D / A), such treatment caused the loss of information and display the results of the defect. LCD, PDP, HDTV and other Xinyi Dai Xian Shiqi Ben Shen of the digital, the traditional approach, computer graphics output from the card (analog) still have further analog-digital conversion (A / D) can be sent to the display, which in turn resulted in new losses and troubles. using DVI interface, the development of LED display systems directly from the PC, the DVI interface to obtain the number of cards like the Galaxy do not need a dedicated graphics card, do not need special the collection card, PC, the limit can not, because there is no D / A conversion process and the MD, to avoid the image detail is lost, thus ensuring the computer image10.4 Inch Touch screen VGA Monitor on the screen in a perfect reproduction. same time, because DVI is an industry standard Suoyisuiran Bandwidth up to 83MHZ, also work well. now DVI supports VGA (640 × 480) to HDTV (1920 × 1080) and QXGA (2048 × 1536) of all the display modes. In addition to using DVI interface, the development of LED display system, stable and reliable display data based on a number of important functions can be integrated
For example: ① no data loss, ② is not limited by the PC machine, ③ easy to upgrade, general graphics card memory 8M, and the card memory for the 128-256M, ④ window position and size of the adjustment; ⑤ frame rate up to 60HZ; ⑥ non- linear adjustment of the output is more suitable for the human eye viewing; ⑦ 100 级 Screen brightness control; ⑧ constant current drive; ⑨ unit board red, green and blue light were adjusted to eliminate the mosaic.
(4) with indoor full color system: the chip display data in addition to the completion of the allocation of tasks, their identity is to receive the 8-bit (8 bit) display data into 12-bit PWM output pulse that allows the display to achieve 4096 ( 12bit) level gray scale control, nonlinear 256 to ensure the realization of visual gray scale, to all true color of the visual effects, can be a fundamental solution to the digital display system as data transmission system caused by excessive complexity.
Has the following characteristics:
① simplicity as the most complex data conversion system parts in order to achieve the form of internal logic chip, the system becomes very simple.
② easy maintenance and simplicity of the system directly related to ease of maintenance, eliminating the need for complex control as part of system maintenance into one by a junior technician can complete the work, which not only reduces the overall maintenance costs , but also improves customer satisfaction.
③ high reliability control system will bring some of the simpler system of high reliability, which was mainly due to separation compared to integrated chip technology has several times the stability of the device technology.
④ cost-effective system to achieve the most reliable performance of 4096 gray screen color control, image display vivid, natural and effective to achieve the same display control.
⑤ unit, structural design and direction of the current development of the industry consistent with a large screen display system in the body of the structure of modular design, the system is simple to connect directly, not only ensure the physical screen size can be adjusted according to8 Inch Touch Screen LCD Panel need stitching, And the system's installation, commissioning and maintenance becomes very easy to minimize the display system failure rate is not visible.
⑥ industrial design system reliability, modular design, replacing the traditional design of a large number of separation devices, the system greatly improved the reliability and stability.
⑦ complete program that contains the data source component systems, transmission equipment, data processing, data distribution and software management tools to enable the construction of LED display into a simple standard. In practical applications, the technology continued to develop and perfect, has become a the most mature, stable, easy to implement system solutions.
⑧ equivalent CRT display LED display most of the core indicators of performance for each primary color (red, green, blue) realized that the brightness level of gray, the display of the current international standard is that each color to achieve Vision 256 gray. special grayscale control chip processing logic can be built out to 4096's gray, and from selection and fitting of CRT display with 256 gray scale output, the overall picture was more clear, vivid, full of infectious .
⑨ high resolution and high refresh rate in addition to gray level, the display of the other two performance indicators are the resolution and refresh rate. As the LED display their own characteristics and requirements, the traditional solution to the loss of which often one or two criteria as another indicator of the price increase. As chips per second per pin data output reached 1 trillion, far beyond the traditional program data output capability8 Inch VGA Monitor
, so that the problem is fundamentally be resolved. The full-color system can simultaneously support 1024 × 768 screen resolution and screen refresh rate up to 300Hz, far beyond the traditional performance solutions to enable the display stable, no flash, no tail.
(5) constant current drive: This circuit technology is mature and reliable, full-color display has been widely used, high cost performance, many companies now commonly used for the constant current driver chip, a better solution of discrete LED tube pressure drop good performance of the defect and eliminate the mosaic.
(6) optical fiber transmission, no attenuation of the fiber-optic transmission technology:
① optical transmission frequency bandwidth, large capacity communication. Fiber available bandwidth is about 1.25G, frequency bandwidth, increase the scanning frequency and the refresh rate, the company designed LED full color screen refresh frequency ≥ 200Hz / s.
② low loss optical fiber transmission, long distance relay. The maximum repeater distance is up to 15,000 meters, improved reliability and stability.
③ optical transmission against electromagnetic interference. Fiber is an insulator material, it is not natural lightning interference, ionosphere interference changes and sunspot activity, but also from high-voltage electrified railway feeder and industrial electrical equipment interference.
④ fiber diameter thin, light weight, soft. Fiber core diameter is very small, about 0.1mm, it is only one per cent of single-tube coaxial cable; cable diameter is small, 8-core optical fiber cross-sectional diameter about 10mm, while the standard coaxial cable to 47mm. use this feature fiber8 Inch TFT LCD Monitor, so little space occupied transmission system. so convenient and fast construction cabling.
⑤ optical fiber transmission has more than obvious advantages but also has strong corrosion resistance, anti-nuclear radiation, the advantages of small energy consumption
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