Second LED history and development
50 years ago, people have to understand miconductor materials can produce light of the weird是什么意思
basic knowledge, the first commercial diodes in 1960. English is the LED light emitting diode (LED) acronym, and its basic structure is an electroluminescent miconductor materials, placed in a wire rack, then aled with epoxy resin around, that is, solid package, Therefore, the protection of the internal batteries can play the role of line, so the ismic performance LED good.
LED is the core of the P-type miconductor and components of the N-type miconductor chips, the P-type miconductor and N-type miconductor between a transition layer, called the PN junction. In some miconductor 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 relea, thus the power to direct conversion of solar energy. PN junction on rever voltage, a few hard-carrier injection, it is not luminous. This u 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, miconductor crystals on the issue from the ultraviolet to infrared light of differefemale是什么意思
nt colors, light and the strength of the currents.
Instruments ud 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 ud 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 cau. 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 irradi
ating a yellow, the peak 550 nm. Blue-chip installed in the LED-bad Wanxing reflection in the cavity, covered with a resin mixed with YAG thin layer, about 200-500 nm. LED-bad 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 u the most.
数量的英文The development of LED display can be divided into the following phas: first pha 1990 to 1995, mainly monochrome and 16 color graphics screen. Ud to display text and simple images, mainly ud in railway stations, financial curities, banks, post offices and other public places, as public information display tools. The cond 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 s
tmc奥巴马毕业演讲pecial 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 enterpris in-depth rearch and development work, using red, green, and blue LED production of full-color display has been widely ud , 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 ud 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 ud for rental after the event, as the performance of national policies such as public places, tools relead by 上海中级口译报名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.
ipad越狱是什么意思Third LED advantages
Conductor light-emitting diode (LED) as a third-generation miconductor 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) hi
gh 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 miconductor light can be ud under normal circumstances 50 years, even if the long life of the people, life will be ud 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) respon time is short: to adapt to frequent and high-frequency switching operation of occasions. 找碴
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