Generally speaking, the display screen is not very large, the area is generally less than 1 square meter to more than ten square meters, and the dot density is high. When used in non-direct sunlight or light environment, the viewing distance is several meters away, and the screen body does not have sealing and waterproof ability. The indoor display screen is mainly dot matrix module, because the brightness of the display screen is not high when it is used indoors, and the use of dot matrix module has a high cost performance. So the price is higher. Outdoor LED

The display screen can be large or small, and the area generally ranges from several square meters to dozens or even hundreds of square meters. According to different customer requirements, the dot density is sparse (mostly 1000-4000 dots/square meter) and the luminous brightness is 3000-6000cd/ square meter (different directions require different brightness). It can be used in direct sunlight with a viewing distance of tens of meters. The screen body has good weather resistance. Semi-outdoor LED

The display screen is between outdoor and indoor, with high luminous brightness, and can be used outdoors without direct sunlight. The screen has a certain tightness, usually under the eaves or in the windows. 2, according to the color is divided into monochrome display, two-color display, three-color LED.

Monochrome of display screen means that the display screen has only one color of luminescent material, mostly single red. Two-color screens generally use red and yellow-green luminescent materials. The three-color screen is divided into full colors, consisting of red, green (wavelength 570nm) and blue; True color consists of red, pure green (wavelength 525 nm) and blue. 3. According to the control mode, synchronous and asynchronous synchronous means that the LED display screen works in the same way as the computer monitor. It maps the image to the computer monitor point by point at the update rate of at least 30 fields/second, and usually has the ability of multi-gray color display, which can achieve the effect of multimedia advertising. Asynchronous mode means that the LED screen has the ability of automatic storage and playback. The edited text and gray-free pictures on PC are transmitted to LED screen through serial port or other network interfaces, and then the LED screen automatically plays offline. Generally, it does not have the ability of multi-gray display, and is mainly used to display text information, which can be networked on multiple screens. 4. Dividing pixels by point spacing At present, the common indoor dot matrix screen screens are P4, P5, P6, P7.62, P8, P 10. The pixel diameter of the indoor screen will basically not exceed 10 mm, mainly due to the small visual distance and the image display effect. At present, there is no uniform standard for pixel diameter and pixel spacing of outdoor screens. According to the number of pixels per square meter, there are about 2500 points, 3086 points, 3906 points, 5 102 points and so on. Common outdoor screens are: P 10, P 12, P 16, P20, P25. Basically, LED lamps are mainly in-line modules. In order to overcome the influence of illumination, outdoor screens need high-brightness LED lights. At the same time, the visual distance of the display screen is related to the pixel diameter, so outdoor screens are basically above P 10. 5, according to the implementation performance

According to the display performance, LED display screen can be divided into: monochrome graphic screen, two-color graphic screen, two-color video screen, synchronous display screen, three-color video screen (full color screen), monochrome bar screen, two-color bar screen, market display screen and various graphics cards. Quotation LED display screen generally includes LED display screens for securities, interest rates, futures and other purposes, which are used to display information, announcements and so on. (1) text display screen, which can only display text and support txt. (2) Graphic display screen: supports files such as TXT and BMP, and can display simple plane pictures. At the same time, it also has the function of offline operation. If you don't change the display content, you can only turn on the power supply of the screen body without turning on the control machine. The display mode supports more than ten modes such as expansion and instant. Content retention can be adjusted arbitrarily (including static) between 0-255 seconds, and different content that users want to display can be displayed automatically and circularly, which can be divided into three types: permanent retention, temporary retention and real-time. After the production is completed, it is sent to the screen through RS232 and RS485 serial ports. (3) Video display screen: The display content is synchronized in real time, and the display screen size can be conveniently selected at will. Color-changing combination * * * 256x256 =16,777,216, the scanning field frequency is more than 200 Hz, which makes people almost invisible to the naked eye, and realizes the correction design of gamma high-speed without gray loss. These parameters can be determined by equipped with advanced and perfect control, production and playback software, which is easy to learn and use. It has dozens of playing modes, can play video information, and has the function of automatically turning off the screen when the computer is turned on and off, which improves the service life of the display screen and avoids the untidiness of the display screen interface when the computer is turned on and off. (4) Screen: Generally, it is one or two lines of monochrome or two colors, and a special remote controller can be used. It has the function of offline operation, that is, the display content is edited and sent to the display screen. There are three storage methods for display content: permanent storage, temporary storage and real-time storage. It can scroll different contents and display 4000 Chinese characters. After the production is completed, it is generally sent to the screen through RS232 serial port and controlled by remote controller. The communication line adopts twisted pair, which has strong anti-interference ability. The communication distance within 100 meters adopts RS232 interface, and the communication distance within 100-500 meters adopts RS485 interface.