畢業(yè)論文LED工業(yè)應用

1、LED industrial applicationAbstract LED (Light Emitting Diode), light-emitting diode, is a solid state semiconductor devices, which can directly convert electric energy into light energy. LED is the heart of a semiconductor wafer, the wafer is attached LED lamp line on a bracket, is negative, the oth

2、er end is connected to the positive electrode of the power, the wafer is epoxy resin package. Semiconductor chip is composed of two parts, one part is a P type semiconductor, it inside the hole is dominant, the other side is the N type semiconductor, here is mainly electronic. But linking the two se

3、miconductor, a P-N junction is formed between them. When the current through the wires on the chip, the electron will be to P area, complex in area P of electrons and holes, and then to form a photonic energy, this is LED light-emitting principle. The wavelength of light determines the color of ligh

4、t, is formed by the P-N node decisions materialskeyword light-emitting diode P type semiconductor N type semiconductor epoxy resin phosphor electron holeForeword1.1 INTRODUCTION Lighting is the human civilization to a great revolution in the light from the darkness, it reflects the human very intell

5、igent, on behalf of the development of history. With the rapid development of industry, people lighting the lamp is not limited to just the lighting. With the high-tech, human demand of environmental protection continuously increasing, energy saving, no pollution, low energy consumption, more and mo

6、re attention by the people, so LED also slowly into peoples eye. LED lighting technology is good, high content of science, because there is no ordinary light bulb filament burn, easy to produce heat deposition, light conditions, long service life, also known as longevity lamp, life is ten times more

7、 than traditional incandescent lamp. It is rich in color, energy saving and environmental protection, green lighting products lighting industry the most fashionable.Should use The composition of a.LED: LED lighting is from LED III-V compounds, such as GaAs (GaAs), GaP (GAP), GaAsP (GaAsP), made of a

8、 semiconductor, which is the core of PN junction. So it is with the characteristics of I-N P-N node, namely the forward conduction, stop, reverse breakdown characteristics. In addition, under certain conditions, it also has the light emitting characteristics. In the forward voltage, electron from ar

9、ea N injected into the P region, P region, N region by injecting hole. Minority carrier into other areas (minority) and a portion of the majority carrier (multi) compound and light. Theory and practice prove, semiconductor material band gap width of Eg peak wavelength of light and emitting region, i

10、.e. lambda = 1240/Eg (mm) in which Eg is the unit of electron volts (eV). If you can produce visible light (wavelength 380nm in purple to red 780nm), semiconductor materials Eg should be between 3.26 1.63eV. The long light than the red light to infrared light. Now the existing infrared, red, yellow,

11、 green and blue light emitting diodes, but the blue diode cost, the price is high, the use is not widespread. Light-emitting principle of LED: LED is light emitting diode, light-emitting diode, is a semiconductor devices semiconductor divided into intrinsic semiconductor, doped semiconductor, diode

12、is doped semiconductor, add 5 valence elements in semiconductor (the people join hole or electron in a semiconductor, semiconductor electronic failure constraints), the electron elegant action, so that the electronic directional mobile form current. LED is made in the principle of the diode, the P/N

13、 junction with epoxy resin dip sealed up, adding fluorescent powder is packaged with a low voltage, high brightness, long life. The relevant parameters of LED: (1) the maximum allowable power dissipation Pm: allows to both ends of LED positive DC voltage and the current flowing through it of the pro

14、duct. Beyond this value, the LED heating, damage. (2) the maximum DC current IFm: maximum DC current allows the. Beyond this value can damage the diodes. (3) the maximum reverse voltage VRm: maximum reverse voltage allowed by the. Beyond this value, the light-emitting diode may be breakdown. (4) the

15、 ambient temperature range of working environment of topm: light emitting diode can work normally. Below or above this temperature range, light emitting diode will not work properly, the efficiency is greatly reduced.Advantages and application of two.LEDAdvantage. High energy: energy saving and no p

16、ollution for environment protection. DC drive, ultra low power (single 0.03-0.06 Watt) electro-optical power conversion close to 100%, the same lighting effect than the traditional energy-saving light source above 80%. Long service life: LED light source is called longevity lamp, is never extinguish

17、ed the lamp. Solid cold light source, epoxy resin packaging, light and no loose parts of the body, there is no filament light-emitting burnability, thermal deposition, depreciation and other shortcomings, the service life of up to 60000 to 100000 hours, than the traditional light source life 10 time

18、s longer than. Changeable Magic: LED light source can use red, green, blue three primary colors of the computer technology, in under the control of the three colors with 256 gray levels and arbitrary mixed, can produce 256 x 256 x 256=16777216 colors, be the most changeful form a combination of different colors, to realize the dynamic changes and all kinds of rich and colorful images. The benefit of environmental protection: environmental benefits, no ultraviolet and infrared spect