For many just contact LED people, LED is a new product, is a unknown material. Then What 's LED?
I'm from the 2008 Olympic Games in Beijing to hear LED this word. That time I also don't know this is what, long what kind. But then chance occurrences, I have been engaged in this line in zhuhai and wanzhou optoelectronic technology Co., LTD. In the face of slowly understanding it: LED (Light Emitting Diode, meaning is the abbreviation of Light Emitting Diode), is actually a long history of the products, from 1907 Henry Joseph Round for the first time in a piece of silicon carbide observe to electroluminescent phenomenon to now has 105 years. That is, the LED already is a "year-old old man, "but he has always been low-key very just.
That he is "low"? Because of the "LED" issued by HuangGuangTai dark, do not accord with the actual application; More difficult in silicon carbide and electroluminescent cannot be very good to adapt, research is slam the door. The late 20 s and Bernhard Gudden and Robert Wichard in Germany from zinc and copper sulfide use extracted luminous yellow phosphorus again shine for dark and stop. Until 1936, George Destiau published a LiuHuaXin powder launch of the light on the report. With the current applications and widely known, to get out of the "electroluminescent" this term.
And then to the 1950 s, the British scientists in electroluminescent experiment with semiconductor gallium arsenide just invented the first modern sense has LED, and appeared in the s. It is said that in the early days of the experiment, the LED need placed in liquid nitrogen, more need further operation to break through to the efficient work at room temperature. The first commercial LED can only send the invisible infrared radiation, but quickly applied in induction and photoelectric domain. May now use on the remote infrared tubes is from here. Of the s, in the gallium arsenide substrate using phosphating things invented the first red LED. When used materials is GaAsP (gallium arsenic p), glowing red (λ p = 650 nm), in the drive current to 20 ma, flux only to per several lumens, corresponding luminous efficiency about 0.1 lumens/watts. To the mid 70's, the introduction of elements In and N, LED Tubes by double phosphating gallium chip, produce green light (λ p = 555 nm), (a red, a green) can emit yellow (λ p = 590 nm) and orange light (λ p = 610 nm), efficacy also improve to 1 lumens/watts. At this time, Russian scientists using emery invention can emit yellow LED, although it as Europe's efficiency. But in the 70 s, it can emit pure yellow light. In the early 80 s, gallium arsenide phosphating aluminum makes use of the first generation of high brightness LED the birth of the first red (GaAlAs LED light source makes red LED efficiency up to 10 lumens/watts), then is yellow, green. By the early 1990 s, use indium gallium aluminum phosphate production out of the orange red, yellow and green light LED.
The first historic blue LED in 1993 is developed, is also used the emery, with today's technology area measure, it and 70 s Russian yellow as dim light. In the mid 90 s, the emergence of a super bright LED the gallium nitride, then he made out of the high strength of indium gallium green light and nitrogen blue LED. 1997 years develop ultraviolet LED. In 1998, Japan, the two villages of the chemistry professor has invented a white light, in blue LED chips onto a layer above yellow phosphor, blue chip stimulate yellow phosphor and converted into a white light. Now in the use of this technology also production any visible color of light. The two villages inside dr.
Also known as "BaiGuangZhi father". Now this technique also widely used by industry, some may use R \ G \ B mixed to achieve the white light effect, but the luminous efficiency is low and the process is relatively complex, generally don't recommend. In the 21 st century, American companies began to develop High Power lumen (Power) LED, will LED chip packing heat sink in copper, with gold thread connection ends to turn out feet sealed the cooling and the purpose of electrical connections. The first high power LED efficacy only 20 lm/W or so. The industry also USES the most imitated lumens structure, In 2001 to start to provide a white LED; Made of GaAlInP led bulbs lights in red, orange area (λ p = 615 nm) efficiency reached 100 lumens/tile, and made of GaInN in LED green areas (λ p = 530 nm) efficiency can be up to 50 lumens/watts. So the whole visible light field LED has complete monochrome, can satisfy all sorts of monochromatic light application places. In October 2003 the United States Cree company has 1200 lumens of the encapsulation white LED integrated lamp, photosynthetic efficiency for 32 lumens/watts. Development up to now, Cree latest laboratory data for 165 lm/W.
The application of high power LED is very wide, can make it LED street light, LED project-light lamp, LED wash wall lamp, LED buried lights, LED underwater light, LED lawn lamp, LED point source, and other outdoor lamps and lanterns; Still can make it LED light bulb, LED light cup (LED shoot the light), LED lamp (LED fluorescent lamp), LED lanterns day, LED canister light, LED bean pot lamp, wall lamp LED such indoor lamps and lanterns. Along with the development of the LED technology, LED lighting lamps and lanterns can certainly alternatives to traditional lamps and lanterns, become a new generation of truly energy conservation and environmental protection products.
