LED display with high brightness, low voltage and power consumption of small, micro and easy to match with the integrated circuit, driving a simple, long life, impact resistance, stability, performance, etc., involving the application of social and economic life in many areas, such as securities Trade, financial information; port of the station to guide visitors information; stadiums, road traffic information; scheduling information center; indoor and outdoor display advertising.

LED screen in the 1980s is gradually emerging electronics, home appliances and therefore part of the maintenance staff on the LED display selection and maintenance of the knowledge is still relatively unfamiliar, give a description of this article. We look forward to inspire commitment to the LED and LED display other products of interest.

I, LED display classification

1. By the way the work of two major sub-categories: full-screen functionality and intelligent displays. Both the use of international standards 8 × 8LED matrix assembled from modules (the same screen surface, the basic display). The main difference between the two:

Intelligent display usually no need to connect PC screen with built-in CPU, power-down to save a number of images can be independent from the PC to run. There are some screen time clock chip that automatically display clock and calendar. When the need to amend the content of the show, through the RS232 interface to connect your PC to amend. The full-function display must connect a computer to work.

Intelligent display screen less often, only the pop-up, pull-screen, roll-on, roll-under, and other shows several ways. The full-function display shows various ways (if using professional software to broadcast programs, shows that there are limitless ways).

Smart Display is simple: full-screen functionality should be available to maintain operations (if the production of animation programs, expertise needed).

2. There are different types of color monochrome and color displays. Monochrome displays adoption of the standard 8 × 8 matrix monochrome LED modules of standard components. General red, shows a variety of text, data, two-dimensional graphics. Indoor monochrome display economical and practical, just some color monotone.

Color display a standard double-base 8 × 8 matrix LED modules, each pixel with red, green and two light-emitting diodes. 2 When the light at the same time, showed yellow. Therefore, two-color board may issue a red, green and yellow colors, color display can be a variety of text, data, animation and so on. In addition, the device can also connect with a wide range of data, real-time display of dynamic data and advertising, the better the effectiveness of the information display, which is currently the most widely used LED display.

Gray color display standard double-base 8 × 8 matrix LED modules, each pixel has red, yellow and green colors, each color there are 16 × 16 = 256 level gray or gray-level 256 × 256 = 64k colors, and even more colors. Gray-scale levels of rich color screen, excellent performance of the force. Can display photos, images, three-dimensional graphics, animation and video images, delicate performance of the rich, vivid and moving visual effects.

3. According to the density of lattice points are common-density and high-density display. The screen pixel density and diameter, the smaller the diameter of pixels, the higher the density of the screen. In the specific selection, to watch the nearer distance, should be the higher density of the screen; viewing distance farther, the display may be appropriate to reduce the density. Standard room for 8 × 8LED matrix module, φ5mm and φ3.7mm the most common.

Second, LED display of the performance requirements

1. LED is the most important in the light-emitting LED die selection. At present, in the light-emitting high-grade core of the pipe manufacturers are Japan's Nichia Corporation, Toyota, the United States Corina, Hewlett-Packard, Siemens AG of Germany Wai, Taiwan, the League of Nations, Yuan Ding and Guanglei companies, , Japan, the United States and Europe, mainly in the production of Chunlan pure green LED-based core, and Taiwan's production of red and green are the main core pipe.

From the current level of practical application and color with red and green, a red screen of the four green, red tube is used in the four elements of red, green tube is used in the three elements of the green. Die in the use of, the League of Nations in general use of Taiwan's Hung 712SOL core pipe, using Taiwan's Ting Yuan 113YGU Green core pipe, which die with the current two-color indoor display a higher allocation . In addition, there are 2 Red Green's pure plus 1 configuration (two-color outdoor).

2. Integrated optical components driving circuit can be spread to the computer to receive from the distribution of cards in the digital signal, the driver of the light-emitting dark and thus we need the text or graphics, the quality of its reliability and stability, directly determines whether the light-emitting-normal工作. At present, the external screen from the room to run, the failure rate highest in the optical drive, because the selected integration IC devices directly determines the quality of the optical drive of some of the quality. At present, the outdoor display general chip is used in 4953 and matched HC595. The higher the grade, using a dedicated drive chip production in Texas and the United States 6B of the 595 series chips.

3. LED display of the power supply requirements to ensure that the 5-year failure of less than 1% of the power of good or bad depends on the quality of the components of the filter and power supply manufacturer of quality control. At present, the market power of the brand more, the Chinese have a joint Changzhou, Guy, Shanghai and Taiwan's Fu Heng-wei-ming. From a practical point of view the use of domestic power Changzhou Star power stability, long service life.

4. Editing systems and system software to play the general requirements of the system software is able to provide a simple and interactive programming / broadcast environment, levels of use, modular design, good reliability and scalability.

Third, the basic structure of the graphic display and control methods

1. The basic structure of the LED graphic display screen, the computer controller, dot-matrix display modules and components such as power supply. Figure 1 for the LED display circuit diagram.

(1) Ping-ping the main part of the dot matrix display, the ranks of the drive circuit, or other circuits (not hard and fast rule, according to the needs and layout of the printed circuit board). The use of dot-matrix display 8 × 8 two-color or monochrome display unit by splicing. For example, 32 × 128 screen of the article, all 64 8 × 8 display units, according to the 4 × 16 block composed of the way.

(2) intelligence unit showed that the unit is independent of the completion of the mission show a small system as a whole, or LED graphic display of a local system, it can display Chinese characters, simple lines, as well as graphics. Control devices are generally used single-chip, and there is the expansion of RS-485 communication interface, and Hanzi Ku shows such as buffers. Intelligence shows that each unit has its own number or address. According to the LED graphic display system size needs to choose the appropriate number of smart display units.

(3) the master control devices using single-chip, and there is the expansion of Hanzi Ku, with brown-out protection, data storage, real-time clock and the calendar of the two HS-485 communications interface, and so on, they are embedded LED graphic Display system. The two communication interfaces, and a computer communications, communication distance of up to several hundred meters; with the completion of all the other intelligent display of the communications unit.

The master of the main functions: to receive commands sent by the computer and display data; command or data will be transmitted to the smart display units, and is responsible for the intelligent display module displayed simultaneously.

In practice, by the master and intelligence units comprising LED display graphic display system that can function independently of the display system.

(4) computer and computer software to complete the appropriate application of the main functions: to be replaced when the content of the show, the updated data to show that in the master; when the need to change the display mode, the master sent to the corresponding Orders; when the need for on-line dynamic display, to the master display real-time data transmission.

As the graphic display of the data showed that only on-off information, including but not gray, not the amount of data, plus the show's content updated more slowly, so, the next bit of data between machines can be used to send serial Asynchronous communication. Serial communication interface level may need to select RS232, RS422 or RS485 standards.

2. LED-screen control by the application of a wide range of different applications and application of environmental requirements may be different control methods. (1) group for its explicit on-screen graphic number, and each screen shows the contents are the same occasion, such as shopping malls, such as the venue. Explicit group on the stage can be a bit more audience-connected machine (graphic screen), shown in Figure 2. It is a unified PC control, use of radio communications: a signal from the PC, all at the same time receive the next bit machine.

When the various needs of different screen graphic content, through to the next bit machine code for the distinction. PC send a message, send the data show that before sending the information needed to receive the next bit machine code, all under the crew received the code, to determine if they should receive the following data show. In this way, should only receive data shows that the next crew to continue to receive, and other places under the follow-up data on the plane ignored, can be realized by all the different screen display. (2) infrared remote control in a number of occasions-and-screen graphic display of the content is relatively simple, which is not frequent changes can not be considered PC. By the crew under its own store a number of necessary data show that, by infrared remote control method, by the staff on duty to choose the content of the scene. We can use the TV's infrared remote control into the screen by remote control.

(3) some type of wireless remote control applications, the graphic layout of the screen is very dispersed, screen and the distance between the screen may be very long. In such a case. PC and next-machine communication between the media and then using cable way. May be unrealistic or not the economy. At this time, wireless can be taken on the way, the next bit of communication between machines. Fourth, the choice of display

LED display to choose its own needs, space constraints, as well as investment and other factors. For example: look at the screen is used indoors or outdoors; the main purpose is to show that the main text, or the main show pictures and simple text, or a variety of major broadcast video, animation, text and images and so on; In addition, the display Viewing distance and which is prepared to take control (control of synchronous or asynchronous control or wireless control, etc.) is also very important factors.

In general, if the image and high visibility distance, the choice of standard high-density point of the two-color or full-color display; words, if a large quantity of players, select a low-density specifications. In addition, funds should be based on the choice of full color, two-color or monochrome display, according to the different circumstances of the decoration timber frame, according to the characteristics of the use of different control methods.

Specifically, the optional LED display should pay attention to the following points:

1. As far as possible wide selection of a new perspective Let it be broad perspective, pure color, consistent coordination, life expectancy more than 100,000 hours.

2. The display outside the package to choose the most popular package is outside the shelter along with a square cylinder, seal silica gel, metal-free assembly. Its sophisticated appearance beautiful, durable, with anti-direct sunlight, dust-proof, waterproof, anti-high-temperature, anti-anti-V characteristics of the circuit short-circuit.

3. According to the different characteristics of the LED display, combined with the user's actual needs, choose the right screen.

(1) for the stations, terminals, market access, the elevator to guide the flow of people, the use of d5.0mm monochrome display. Font with a clear, inexpensive, the advantages of group control.

(2) For banks, shopping malls and so on display for the corporate image, advertising, and other applications requiring low cost, the use of φ3.75mm two-color display. If the results show that good can be used φ5mm full-color screen.

(3), and other large hall for the occasion, φ5mm the use of two-color display. If the results show that the use of φ10mm full-color screen.

(4) for banks, postal services, electricity, and other business lobby, for services to the definition functionality of the window, the use of φ3mm or φ5mm display screen, at any time in order to facilitate the replacement of windows services.

4. Because the use of outdoor display conditions for a higher quality requirements, it is necessary to consider many factors.

(1) from the point of use, full-color screen is the mainstream in the future. Because of their high-brightness, full-color, full-Hou, but high prices. (2) application from the point of view, to meet the needs of users of the products exist there. Two-color screen to display text in color modest, there is no occasion for the blue, with its low cost, occupy very mature and stable market.

(3) towards the external screen room, away from price plays a decisive role. The farther the distance, the greater the pixels, the higher the brightness. Towards the north-east than the south-west towards the screen is much cheaper.

(4) screen-and-screen combination with the construction of the Department must be strictly leak-proof water-proof. Ping-good drainage, stagnant water in the event of a successful emissions.

(5) display in the building and install lightning protection devices. The main display case and maintain a good grounding, grounding resistance is less than 3Ω, so that the lightning caused by the large current discharge in a timely manner.

(6) the installation of ventilation cooling, so that the internal body temperature in the screen -10 ℃ ~ 40 ℃ between. Is also available on-screen installed behind the top of the axial flow fan, exhaust heat.

(7) selected in the operating temperature -40 ℃ ~ 80 ℃ between the IC chip industry level, the winter temperature is too low to prevent the display could not be activated.

Fourth, and common Fault approach

1. Screen does not show

(1) screen check-in power supply, use or Shidian Bi multimeter detection switch to connect with the Office whether there are electrical power. Switch problems, or whether the inspection line break.

(2) and the simultaneous computer screen, first check whether the computer into hibernation; if we went into hibernation, first into the Control Panel, click Power Management, the system will wait and monitor the closure of the options to choose from options, so that The computer will not sleep, can display work; if not into hibernation, you can open the box, the control card to see whether the plug cable and communications firm to check whether there is a broken communications cable. 2. Documents show that incomplete or wrong location

(3) Check the software screen shows the location and size parameters, with the engineers to install the line. If we do not know the parameters in the first few on-screen look long and the width of the pixel point, when the screen size to determine, on-screen look at the difference between the number of display area, and then return to the Department of Computer adjusted until the location of the match so far .

(4) shows that if there is not comprehensive, should be done by checking the file size screen with the screen-size line.

(5) open the box, check to control whether or not there is a short circuit on the card. 3. Communication is not on display communication

(6) Check whether the parameters of the software engineers to install and to the agreement.

(7) Check whether the serial port access in prison, whether there is a line of communication lines.

2. Display jitter, bar

Check your computer to connect the ground wire is a total loose, loose or whether the communications cable. If operators can not determine the cause of the problem, or the computer is not very well, do not easily separate chassis, and then contact the manufacturers to deal with it.

Reference link: http://www.17led.com/LEDdisplay/2008-05/76.html