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06 Apr 2011
60's in last century, the science and technology worker makes use of semi-conductor PN the knot gives out light of principle,LED light develop LED give out light diode.LED developed at that time, the material used was GaASP, it gave out light the color as red.After 30 years of development, everyone pretty much acquaints with now of LED, can already send out red, orange, Huang, green and blue etc. is various color lights.However lighting white that need to be used light LED just develop just in the recent years, LED flood lighthere introduce toward the reader concerning the lighting to use white light LED.

1.It is thus clear that light of spectrum and LED white light of relate to.Many weeks it, it is thus clear that light the wave-length scope of the spectrum is a 380 nms~the 760 nms is seven color lights that person's eye can feel-red, orange, Huang, green, green, blue and purple, but these lights in seven kinds of colors are all respectively a kind of monochrome light.For example LED the Feng of the red light of the hair is worth wave-length for 565 nms.At it is thus clear that light of have no white light in the spectrum, because the white only isn't a monochrome light, and from various monochrome light synthesize of compound light, LED spot lightpositive such as the sun only from seven kinds of monochrome light synthesize of white light, and color television in of white be only also synthesized by red, green and blue three radicle colors.Be showed from this, make LED send out white light, its spectrum characteristic should include whole it is thus clear that of spectrum scope.But want to make LED of this kind of function, is impossible under the current craft condition.According to people to it is thus clear that light of study, person's eyes can see of the white need two kinds of mixtures of lights at least only, namely two wave-lengths give out light(blue light+yellow light) or three wave-lengths give out light(blue light+green light+red light) of mode.Above-mentioned two kinds of modes of white all need blue light only, LED strip lightso take a blue to only have become the key technique of making the white light, namely at present each big LED manufacturing the company pursue of"blue light technique".International currently up control the manufacturer of "blue only technique" to only have minority of several houses, for example Japan of day second chemistry, the Toyota of Japan synthesizes, CREE of the United States,LED tube light department Lang in Europe of Germany etc., so white only the LED expansion apply, particularly is Gao Liang Du white light LED at our country of the expansion still has a process.

2.White light LED craft structure and white light source.For general illuminate, on the craft structure, white only LED usually adopts two kinds of method formations, the first is the exploitation"blue light technique" and fluorescence powder to match with formation white light;The second is various monochrome lights mixture method.These two kinds of methods can already succeed to produce white light spare part.The first system of method creation white light such as figure 1 show, the chip of LED GaM in diagram delivers blue light(λ p=465 nms), it and YAG(Yi aluminum garnet) fluorescence powder packs together and be the fluorescence powder sends out after being subjected to blue the light stir up yellow light, LED Ceiling Lightresult, blue light and Huang Guang mix formation white light.(constitute LED structure such as figure 2 show)The second method adopts a different color light of the chip pack together and pass each color light mixture but produce white light.

3.white light LED illuminate the applied foreground of new light source.For explaining white only LED characteristics, sees first currently use of the condition of floodlight light source.Incandescent lamp and stew a Wu light, its radiation for 12~24 flow clear/tile;The radiation of the fluorescent lamp and HID light for 50~120 flow clear/tile.Dialogue light LED:In 1998, white light LED radiation only 5 flow clear/tile, arrive in 1999 already arrive 15 flow clear/tile, this index sign is similar to generally household-use incandescent lamp, Educational Baby toysbut in 2000, white light LED radiation already 25 flow clear/tile, this index sign with stew a Wu light close by.Have the company the estimate, till 2005, the LED radiation can reach to 50 flow clear/tile, arrive in 2015, the LED radiation may attain 150~200 flow clear/tile.That time of white light the LED work electric current then can reach ampere class.Be showed from this development white only the LED writer is used lighting light source, will become possible reality.

Common incandescent lamp used in lighting and stew a Wu light although price cheapness, the radiation is low(the hot effect white white of light consumes an electricity), the life span is short and support a work to have great capacity, if use white only LED illuminates, not only radiation Gao, and life span long(continuous for more than 10000 hours working times), almost didn't need to be supported.Currently, the Germany Hella company makes use of white only LED developed airplane reading light;Capital city in Australia may the Pei pull of a street have already used white light LED make street lamp lighting;Our country of transportation in the city manage the light is also using white light LED replace the transportation order of earlier period indicator.Learn MandarinCan foresee near future, white light LED will certainly get into a family to replace existing floodlight.



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