LED manufacturing supplier
The history of LED
Source: | Author:sunpzone | Publish time: 2015-10-06 | 3350 Views | Share:
LED

First LED Summary LED (Light Emitting Diode), light-emitting diode, is a solid state semiconductor devices, which can be directly converted into electricity to light.

LED is the heart of a semiconductor chip, the chip is attached to one end of a stent, is the negative side, the other end of the power of the cathode, the entire chip package to be epoxy resin. Semiconductor chip is composed of two parts, part of the type semiconductor, it inside the hole-dominated, the other side is the N-type semiconductor, here is mainly electronic. But linking the two semiconductors, among them the formation of a "PN junction." When the current through the wires role in this chip, will be pushing e-P, P zone in the hole with electronic composite, and then to be issued in the form of photon energy, and this is the principle of LED luminescence. The wavelength of light that is the color of light, is formed by the PN junction of the decisions of the material. Second LED history and development 50 years ago, people have to understand semiconductor materials can produce light of the basic knowledge, the first commercial diodes in 1960. English is the LED light emitting diode (LED) acronym, and its basic structure is an electroluminescent semiconductor materials, placed in a wire rack, then sealed with epoxy resin around, that is, solid package, Therefore, the protection of the internal batteries can play the role of line, so the seismic performance LED good.

LED is the core of the type semiconductor and components of the N-type semiconductor chips, the type semiconductor and N-type semiconductor between a transition layer, called the PN junction. In some semiconductor materials in the PN junction, the injection of a small number of carrier-carrier and the majority of the extra time will be in the form of light energy to release, thus the power to direct conversion of solar energy. PN junction on reverse voltage, a few hard-carrier injection, it is not luminous. This use of injection electroluminescent diodes is produced by the principle of light-emitting diodes, commonly known as LED. When it in a positive state of the work (that is, at both ends with forward voltage), the current flows from the LED anode, cathode, semiconductor crystals on the issue from the ultraviolet to infrared light of different colors, light and the strength of the currents. Instruments used for the first LED light source instructions, but all kinds of light colored LED lights in traffic and large screen has been widely applied, have a very good economic and social benefits. The 12-inch red traffic lights as an example, is used in the United States have long life, low-efficiency 140 watt incandescent lamp as a light source, it produced 2,000 lumens of white light. The red filter, the loss-90 percent, only 200 lumens of red light. In the light of the new design, Lumileds companies have 18 red LED light source, including the loss of circuit, a total power consumption of 14 watts to generate the same optical effect. Automotive LED lights is also the source of important areas. For general lighting, people need more white light sources. The 1998 white LED successful development. This is the GaN LED chip and Yttrium Aluminum Garnet (YAG) package together cause. GaN chip of the Blu-ray (λ p = 465nm, Wd = 30nm), made of high-temperature sintering of the Ce3 + YAG phosphors excited by this Blu-ray after irradiating a yellow, the peak 550 nm. Blue-chip installed in the LED-based Wanxing reflection in the cavity, covered with a resin mixed with YAG thin layer, about 200-500 nm. LED-based tablets issued by the Blu-ray absorption part of the phosphor, the phosphor another part of the Blu-ray and a yellow light mixed, can be a white. Now, the InGaN / YAG white LED, YAG phosphor by changing the chemical composition of the phosphor layer and adjust the thickness of the 3500-10000 K color temperature can be colored white. This blue LED through the method by white, constructed simple, low-cost, high technology is mature, so use the most. The development of LED display can be divided into the following phases: first phase 1990 to 1995, mainly monochrome and 16 color graphics screen. Used to display text and simple images, mainly used in railway stations, financial securities, banks, post offices and other public places, as public information display tools. The second stage is from 1995 to 1999, there have been 64, 256 level gray-scale two-color video screen. Video control technology, image processing, optical fiber communication technology applications will enhance the LED display to a new level. LED display control LSI chips special at this time developed by domestic companies, and can be applied. The third stage, from 1999, red, pure green, blue LED in bulk into China, while domestic enterprises in-depth research and development work, using red, green, and blue LED production of full-color display has been widely used , poured into sports stadiums, convention centers, squares and other public places, which will bring the domestic large-screen full-color era. With the rapid development of LED materials market, surface mount device is available from 2001, mainly used in indoor full color, and its high brightness, colorful, low temperature characteristics, the point spacing can be adjusted by different price Requirements were accepted, in just two years time, product sales have more than 300 million yuan, surface mount full-color LED display application market entered the new century.

To meet the 2008 Olympic Games, "downsizing" plan, Liard developed a surface mount dual color displays, a lot of time for the training center and game scoring. Full color in Olympic venues, in order to tighten investment, full color way is mostly detachable, live during the Olympic Games as a tool can be used for rental after the event, as the performance of national policies such as public places, tools released by In this way cost recovery as soon as possible. On the market, China's accession to WTO, Beijing's successful Olympic bid and so on, into the development of LED display industry, a new opportunity. Domestic LED display market continues to grow, currently in the domestic market, domestic LED display market share of nearly 95%. LED display the international market capacity is expected to 30% a year growth rate. Currently, LED display manufacturers concentrated primarily in Japan, North America, China LED manufacturers in which the insignificant share of exports. According to incomplete statistics, the world, there are at least 150 manufacturers full color, in which products are complete, the larger company has some 30 or so. Third LED advantages Conductor light-emitting diode (LED) as a third-generation semiconductor lighting source.

This fantastic product has a lot of advantages: (1) efficient light: spectra of almost all concentrated in the visible light frequency, the efficiency can reach 80% -90%. The luminous efficiency of incandescent visible light efficiency of almost 10% -20% only. (2) high quality of light: not as a result of spectrum UV and infrared, there is no heat, no radiation, is typically a green light illumination. (3) energy consumption of the small: single power generally 0.05-1w, through the cluster can be tailored to meet different needs, and waste very little. As a light source, under the brightness in the same power consumption of only ordinary incandescent 1/8-10. (4) long life: flux attenuation to 70% of the standard life expectancy is 100,000 hours. A semiconductor light can be used under normal circumstances 50 years, even if the long life of the people, life will be used up to two lights. (5) durable and reliable: No tungsten wire, glass and other easily damaged components, non-normal retirement rate is very small, very low maintenance costs. (6) the application of flexibility: small size, can flat pack, easy to develop into a short thin products, make point, line, face various forms of specific applications. (7) Security: working voltage 1.5-5v or less in between the current 20-70mA in between. (8) green: recyclable waste, no pollution, unlike fluorescent lamps containing mercury as ingredients. (9) response time is short: to adapt to frequent and high-frequency switching operation of occasions.

Fourth Classification of LED display 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: 7 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 formed by a number of 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 according to light spot diameter Indoor screen: Φ3mm, Φ3.75mm, Φ5mm, Room external screen: Φ10mm, Φ12mm, Φ16mm, Φ19mm, Φ20mm, Φ21mm, Φ22mm, Φ26mmRoom 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. Fifth LED applications It is a semiconductor light-emitting diode by controlling the display, which probably look like that from lots of small red lights are 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, graphics, images, and Mao, real-time, synchronization, clear message to the broadcast of a variety of information dissemination, 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. Sixth LED screen test method A look at Screen size, appearance, smoothness, with the screen connection and so on Second look after the dead pixel screen light up, not in not within the scope of (in general the screen is basically gone now) Color consistency, display text is normal, display pictures, play full screen full color to white, red, green, and blue.