LED daylight lamp and the Principle of its light-emitting

一 .The frame of LED and the principle of it’s light-emitting,people knew the basic knowledge that the simiconductor materials can emit lights 50 years ago.and the first LED produced for commercial use in 1960.LED is the abbreviation of light emitting diode.and it’s basic frame is the light-emitting simiconductor material and then putted on a shelf which have a lead line,then sealed with epoxy resin,in this way,the chips contained it can be proteced very well.so it has high ability of resisting vibration.the essential part of LED is consist of P simiconductor and N simiconductor,between the two simiconductors has a over layer,which is call P-N knot.in some simiconductor material’s P-N knot,minor carriers combinated with many other carriers inputed in it can converse the extra energy into light and then release it.so it can transfer power into light directly.however,if the PN knot is inputed with reverse voltage,minor carriers can’t be injected,so there is no light can be produced. This kind of diod that use the priciple of ligh-emitting is called light emitting diod,which is generally named LED.when it in a forward working position,(the two ends connected with positive voltage),the current flow from anode to cathode.the simiconductor chip will produce various colors from ultraviolet to infrared.the stength of light is close to the current.

二. The characteristics of power supplier 1.voltage:LED uses low power supplier,and the inputed voltage is between 6-24v,and it can be adjusted according to different products.so it’s a safer power supplier compared with the high power supplier and especialy suitable for the public places. 2.efficiency:power consumption is less than 80% compared with the other daylight lamp with the same brightness. 3.adoptability:each LED chip is very small,which is a rectangle of 3 to 5 square meters,so it can be made different types of compliances and suitable for variable environment. 4.stability:100 thousand hours,light failure is half of the initial value. 5.environmental protection:contains no mercury or lead. 6.reponse time:the general kind of daylight lamp is counted by millisecond, but the LED daylight lamp is counted by NS. 7.color:the led tube can display various colors such as Red,Yellow,Blue and any other colors by using chemical modification method,adjusting materials’ band structure and gap.

三. The types of sigle color and it’s development of history The supplier power of LED firstly used the principle of light-emitting was founded in the early of 1960s,the material used at that time is GaAsaP,which emit red light (λp=650nm),when the driving current is around 20 MA,the flux is a few part per thousand lumen,and the light-emitting efficiency is about 0.1 Lumen/watt. In the middle of 1970,by using the elements of IN and N, LED produced green light(λp=555nm),yellow light(λp=590nm) and orange light(λp=610nm),and the light-emitting efficiency was enhanced to 10 lumen/watt. In the early of 1990s,two new materials which produce red and yellow,green and blue light were produced respectively.as a result,the LED’s light-emitting efficiency was greatly enhanced. In 2000,the LED’s light-emitting efficiency that produced by the former was enhanced to 100lumen/watt,and by the latter was enhanced to 50lumen/w.

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