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1、A Research&Fabrication of Packaging Technology for High Power White LEDComparing with the traditional incandescent and fluorescent lighting, the high Power white LED has many significant incomparable advantages such as energy saving, envirorunental protection, long life and so on. It represents the
2、development direction of green lighting, and is moving into the field of lighting rapidly. From the packaging technology of 1 W high-bower white LED, the cost and performance of several methods were analyzed and compared for white light LED. Based on this, using the“blue chip&YAG phosphor for produc
3、ing white light LED is the final selection with its good perfounance and proper price. The results show that in improving the light emitting efficiency, unilounity and stability of high-power white LED, it needs further development of new materials and new technology.IntroductionLED use semiconducto
4、r chips of solid as light emitting materials, the use of electric light-emitting. As a light source, LEDs advantages is in energy saving, environmental protection and long-lived three aspects. LED does not depend on heating filament to light-emitting, energy conversion efficiency is very high, in th
5、eory only 10% of the energy consumption of incandescent. compared with fluorescent, LED can be up to 50% of the energy saving effect. Special survey showed that the annual electricity consumption of Chinas lighting is more than 300 billion, to replace all incandescent lamps with LED or in part or to
6、 replace the fluorescent lamp, can save 1 / 3 of the lighting electricity, means that the saving of 1 000 billion kwh, representing the full-years generating capacity of Three Gorges Project which investment of more than 200 billion. Using LED to replace fluorescent lamps, bamboo lamps to avoid the
7、breakdown of a spill of mercury pollution, moreover waste and manufacturing backplane LED (Copper Clad Aluminum) reuse can be recycled. LED by solid package, the structure is deep-set , life expectancy can be up to h. In addition, LED also has a low operating voltage, power consumption in small, hig
8、h luminous efficiency, response time is very short (ns-grade), pure light color, light weight, small size, such as a series of characteristics of rapid development, especially high-power high-brightness white light LED of the invention, by the insider as the lighting the area of the third revolution
9、.following make fire lighting, after Edison invented the lamp .White LED production methodAt present, the way to product white light with LED chips show in the table1.Tab.1 Preparation principle of“blue chip&YAG phosphorThe way of The white light production methodAdvantagesDisadvantagesCaN single gr
10、ain Blue light LED +fluorescent materialSingle grain production method, low cost, electronic circuit, designed is simpleLuminous efficiency is low; of poor color; fluorescent material is not easy to find; limited phosphor coating, so thewhite light is not evenUV LED (375nm) + fluorescent materialPho
11、sphor material is not easy to find, will enable the conversion efficiency higher than the YAG fluorescent material, light-emitting efficiency of space; good colorLuminous efficiency is low; packaging materials are easy to produce ultra-violet by UV light ; limited phosphor coating, so thewhite light
12、 is not evenZnSe single grainBlue LED + ZnSe substrate Single grain product white light, low cost; low drive voltage (2.7); without the use of phosphorLuminous efficiency is 50% lower than CaN, about 8lM / W; short life, only 8000hDual-wave single grainwhite lightSingle grain product white light,Oth
13、er to be done to be doneMulti-grainGreen, blue & red, green and blue multi-color combinationsHigh luminous efficiency; can be dynamically adjusted color-temperature; of good color; natural colorThe needs of three grains, the grain of the need for individual electronic circuit design, high cost; poor
14、 of the close-up color; multi-color LED light-emitting efficiency is not evenAs a result of blue light chips + YAG phosphor have a white LED production method of the lowest cost, practicalitys characteristic has become the mainstream products on the market. Therefore, the experiment chosen this meth
15、od to product white LED.Key processes and technical measures Compared with the ordinary white-light LED, the high-power (W-class power) white LED has a higher power and more heat, therefore, in the packaging process, be considered light, electricity, heat and other factors.Flip-chip technology Insta
16、lled in the traditional way of LED chip package, because of P-type doped GaN difficulties, the current widely used in the preparation of P-type GaN metal transparent electrodes on the ways in which even the spread of current in order to achieve the purpose of light-emitting uniformity. P-type GaN on the transparent electrode metal to absorb 30% to 40% of a light, wh
