Hard LED is display of light emitting diodes, which probably is composed of a lot of red LEDs are usually led by the bright lights out to display characters. Used to display text, graphics, images, animation, market, video, video signals and other information display screen. led screen background LED illuminant colour and efficiency and the production of LED material and technics, ball lamp started full Blu ray, but followed by fluorescent powder, according to the different needs of the user, adjust the different color, the currently widely used are red, green, and blue. Due to low working voltage of the LED (only 1.5~3.6V), active luminescence and certain brightness, brightness and voltage (or current) regulation, and impact resistance, vibration resistance, long service life (1 00000 hours), so in large display equipment.
At present, there is no other display mode and LED display mode is equal to. The red and green LED on together as a pixel display for monochrome and color to red, green and blue three LED tube is put together as a pixel of the display color screen or full color. If only one kind of color is called color, make indoor LED screen pixel size is generally 2-20 mm, often adopt several can produce different colors of LED die package as a whole, outdoor LED screen pixel size for 8-32 mm, each pixel consists of a plurality of various monochromatic LED composition, common product called pixel tube, double color pixel tube generally consists of two red, one green, three color pixel tube with red 1 1 green, 1 blue composition. Regardless of the production of a single color, double color or three color screen with LED, to display the image needs to constitute a pixel of each LED brightness must be able to adjust the brightness, the precise level of its adjustment is the gray level of the display screen.
The higher the gray level, the more delicate the image shows, the more rich color, the corresponding display control system is also more complex. General 256 gray level image, the color transition has been very soft, and 16 gray level of color images, the color of the transition line is very obvious. Therefore, the color LED screen is currently required to make the 256 to 4096 gray level. Used in display of the LED luminescent material has the following forms: LED light emitting lamp (or single lamp) general by a single LED chip, reflective bowl, metal anode, metal cathode, outsourcing has light gathering ability of epoxy resin shell. One or more (different colors) of a single light to form a basic pixel, due to high brightness, and more for outdoor display. The LED dot matrix module is composed of a plurality of chips which form a light emitting matrix, and the epoxy resin is encapsulated in a plastic shell. For a scanning drive, easy to form high density display for indoor display.
The patch type LED light-emitting or SMD LED lamp is an LED luminescent lamp stick welding form package, for indoor full color display, can achieve single point maintenance, effectively overcome the mosaic phenomenon. led display screen LED (LED): also called the electronic display screen or floating word screen. Is composed of LED dot matrix and PC LED panel, through the red, blue, white, green LED lights out to display the text, pictures, animation, video, content. We can according to the needs of different occasions to make different regulation, such as the general billboard that flows of calligraphy and painting, is through flash produced a animation, savings in the display of a memory card, through the techniques displayed can according to the different needs change, each component is the modular structure of the display device.
Traditional display screen is usually composed of display module, control system and power supply system. LED, ScreenLED LEDdisplay has received widespread attention and rapid development, and it has the advantages of its own is not open. The advantages are: high brightness, low operating voltage, low power consumption, large scale, long life, impact resistance and stable performance. Led the development prospect is extremely broad, is currently towards a higher brightness, higher resistance to climate, and higher luminous density, higher luminous uniformity, reliability, full color in the direction of development. LED display control with 1024-4096 super gray gray control, display color 16.7M, color clear, strong sense of three-dimensional. The static scanning technique using static latch scanning mode, power drive, and fully guarantee the brightness. Automatic brightness adjustment with automatic brightness adjustment function, can obtain the best playback.
.LED display to maintain the brightness at the same time in different illumination environments, there are also disadvantages, is in the rainy day, LED display after rain, people's eyes for a long time close to the display will easily induce eye diseases, appear tears, this source of pollution, LED display as environmental protection technology should be fully considered to need more light on the people the influence of the spirit, not excessive pursuit of brightness full use of imported large scale integrated circuit greatly improved reliability, easy to debug dimension Support.
The superior performance of LED display,
1) : strong brightness in the visual distance, sun screen surface, display content clearly visible.
2) LED display control with 1024-4096 super gray gray control, display color 16.7M, color clear, strong sense of three-dimensional.
3) static scanning technology, using static latch scanning the way, high power drive, fully guarantee the luminance of automatic brightness adjustment with automatic brightness adjustment function, can obtain the best playback of in different illumination environments) with fully imported large scale integrated circuit greatly improved reliability, convenient maintenance and debugging. digital video processing, advanced technology, distributed scanning.
4) LCD BSV technology of high-definition display, modular design /constant current static drive, automatic brightness adjustment, super Gao Liangchun Color pixels, image clarity, no jitter and re shadow, to eliminate distortion. Video, animation, graphics, text, images and other information display, online display, remote control. LED color and manufacturing process of such materials is different, can produce photons with different energies, whereby you can control the LED emits light of wavelength, is or color spectrum. The history the first led by the use of materials is a GaAs (GA), the positive PN junction voltage (VF can understand light or voltage) 1.424V, a light for infrared spectroscopy.
(As) 2 other commonly used LED material for phosphorus (P) Ga (Ga), the positive PN junction voltage is 2.261V, the light is green. 3. Based on the two materials, early led industrial use GaAs1-xPx materials structure and theory can be produced from infrared to green within the scope of any wavelength of LED, the subscript x represents a phosphorus element to replace the percentage of arsenic. In general through the PN junction voltage can determine the LED wavelength and color. Typical of which there are GaAs0.6P0.4 red LED, GaAs0.35P0.65 orange light LED, GaAs0.14P0.86 yellow light, etc.. Due to the manufacture of gallium, arsenic, phosphorus three elements, so commonly known as these three elements of the LED light-emitting tube.
And GaN (Dan Huajia) of the Blu ray, GaP green LED and GaAs infrared LED, known as the two elements of the luminous tube. At present, the latest technology AlGaInN mix of aluminum (AL), calcium (CA), indium (in) and nitrogen (n) of the four elements of the four elements of the material for manufacturing the four elements of the LED, can cover all visible light and part of UV spectral range. Led LEDled display - color light bulb 4. luminous intensity unit of measure unit of illuminance (Lux Lux) and luminous flux unit lumen (LM), luminous intensity (candela candle power unit 5. 1CD (candles) refers to the complete radiation of objects, in platinum freezing point temperature, every six is one square centimeter area of luminous intensity. (previously referred to as 2.2 cm in diameter, quality is 75.5 g spermaceti candle, per hour to burn 7.78 grams, flame height is 4.5 cm, along the horizontal direction of the luminous intensity). 1L (LM) refers to the CD 1 candle light irradiation at a distance of 1 cm, with an area of 1 square centimeter level of luminous flux. 7.1Lux (Lux) refers to the luminous flux of 1L evenly distributed in the area of 1 square meters of the illumination. 8. General active luminous body the luminous intensity unit candlelight CD, such as incandescent lamps, LED; luminous flux per lumen l reflection or transmission of objects using, such as LCD projector; and unit of illuminance lux lux, generally used for photography and other fields. The three measure is equivalent in value, but it needs to be understood from different angles. For example: if a LCD projector brightness (flux) for 1600 lumens, the projection to the total reflection screen size is 60 inches (1 m2), and the illumination for 1600 lux, assuming the burring 1 cm away from the light source, burring area of 1 square cm, is a light outlet of the luminous intensity is 1600CD. And the real LCD projector due to the loss of light transmission, reflection or transmission loss and light distribution of the film is not uniform, the brightness will be greatly reduced, generally 50% of the efficiency is very good. 9 in practical use, the light intensity calculation is often used to compare the data unit of Surveying and mapping.
For the LED display screen the active luminous body generally use CD /square meters as a unit of luminous intensity, and with the point of view as the auxiliary parameter, the equivalent to the surface of the screen body unit of illuminance lux; will this value and screen effective display area multiplied, get the whole screen body in the best view of luminous intensity, each pixel in the screen body luminescence intensity in the corresponding space constant hypothesis, this value can regarded as the luminous flux of the whole screen body. General outdoor LED display to reach 4000CD/square meters above the brightness before daylight has a more ideal display effect. General indoor LED, the maximum brightness of 700 ~ 2000 CD/square meters. The luminous intensity of a single CD is LED as a unit, and with the angle of view, the luminescence intensity is not related to the color of LED. The single luminous intensity from several mCD to five thousand mCD range.
The luminous intensity given by the LED manufacturer refers to the point where the LED light is lit at the 20mA current, and the maximum luminous intensity at the optimum angle of view and the central position. The shape of the top lens and the position of the LED chip are determined by the shape of the top lens and the position of the LED chip at the top of the LED. In general the same led the visual angle is large, maximum luminous intensity is small, but accumulated in the three-dimensional hemispherical flux unchanged. 10 when a plurality of LED are discharged, the luminous sphere of the luminous surface is mutually overlapped, and the luminous intensity distribution of the whole luminous plane is relatively uniform.
In the calculation display luminous intensity, according to the emissions intensity of LED and led perspective, the manufacturers to provide the maximum emission intensity values are multiplied by 30% ~ 90%, ranging from, as a single average luminous intensity. 11. General LED light-emitting life is very long, manufacturers generally marked as more than 1 00000 hours, actual should also pay attention to the LED brightness decay cycle, such as most for automobile taillight ur red tube light more than a dozen to a few hours after the brightness, the only original half. The period of brightness attenuation is very much related to the material technology of LED production. In general, the four elements of the brightness attenuation should be selected in the condition of economic conditions permit LED. 12. White is the colour is red, green and blue color mixed according to the brightness ratio and, when the brightness of green in the light of 69%, the intensity of red is 21%, the intensity of the blue is 10%, mixed color descendants feel eye is pure white. But the chromaticity coordinates LED red and green and blue as a result of the process etc.