点子王Photoelectric nsor
Key word： photoelectric effect photoelectric element photoelectric nsor classification nsor application characteristics .
Abstract：我爱足球 in the rapid development of science and technology in the modern society， mankind has into the rapidly changing information era， people in daily life, the production process, rely mainly on the detection of information technology by acquiring, screening and transmission, to achieve the brake control, automatic adjustment， at prent our country has put detection techniques listed in one of the priority to the development of science and technology。 Becau of microelectronics technology， photoelectric miconductor technology, optical fiber technology and grating technical development makes the application of the photoelectric nsor is growing。 The nsor has simple structure, non-contact， high reliability, high precision, measurable parameters and quick respon and more simple structure， form etc, and flexible in automatic detection technology， it has been widely applied in photoelectric effect as the theoretical basis， the device by photoelectric material composition.
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First, theoretical foundation - photoelectric effect
臣诚恐见欺于王而负赵翻译Photoelectric effect generally have the photoelectric effect， optical effect, light born volts effect.
吃东西牙疼The light shines in photoelectric material， according to the electronic absorption material surface energy, if absorbed energy large enough electronic electronic will overcome bound from material surface and enter the outside space， which changes photoelectron materials， this kind of phenomenon become the conductivity of the photoelectric effect
时解脱
According to Einstein’s photoelectron effect， photon is moving particles， each photon energy for hv （v for light frequency， h for Planck's constant, h = 6.63 ＊ 10—34 J/HZ）, thus different frequency of photons have different energy， light， the higher the frequency， the photon energy is bigger. Assuming all the energy photons to photons， electronic energy will increa， incread energy part of the fetter， positive ions ud to overcome another part of converted into electronic energy. According to the law of conrvation of energy：
Type， m for electronic quality, v for electronic escaping the velocity， A microelectronics the work done。
From the type that will make the optoelectronic cathode surface escape the necessary conditions are h > A. Due to the different materials have different escaping， so reactive to each kind of cathode materials, incident light has a certain frequency is restricted， when the frequency of incident light under this frequency limit, no matter how the light intensity, won’t produce photoelectron launch, this frequency limit called ”red limit”. The c
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orresponding wavelength for type， c for the speed of light， A reactive for escaping.
When is the sun， its electronic energy， absorb the resistivity reduce conductive phenomenon called optical effects。 It belongs to the photoelectric effect within. When light is, if in miconductor electronic energy big with miconductor of forbidden band width, the electronic energy from the valence band jump into the conduction band, form, and at the same time， the valence band electronic left the corresponding cavities. Electronics, cavitation remained in miconductor, and participate in electric conductive outside formed under the current role。 祛痰止咳
In addition to metal outer, most insulators and miconductor have photoelectric effect， particularly remarkable, miconductor optical effect according to the optoelectronics manufacturing incident light inherent frequency, when light resistance in light， its conductivity increas, resistance drops。 The light intensity is strong, its value， if the smaller， its resistance to stop light back to the original value。
Semiconductor produced by light illuminate the phenomenon is called light emf, born volt
s effect on the effect of photoelectric devices have made si-bad ones， photoelectric diode, control thyristor and optical couplers， etc。
Second, optoelectronic components and characteristics
According to the outside optoelectronics manufacturing optoelectronic devices have photoelectron， inflatable phototubes and photoelectric times once tube。
1. Phototubes phototubes are various and typical products are vacuum phototubes and inflatable phototubes, light its appearance and structure as shown in figure 1 shows, made of cylindrical metal half cathodic K and is located in the wires cathodic axis of anode in A package of smoke into the vacuum, when incident light within glass shell in the cathode， illuminate A single photon took all of its energy transfer to the cathode materials A free electrons, so as to make the freedom electronic energy increa h。 When electrons gain energy more than escape of cathode materials， it reactive A metal surface constraints can overcome escape， form electron emission。 This kind of electronic called optoelectronics， optoelectronic escaping the metal surface for after initi
al kinetic energy
贸易合同Phototubes normal work, anode potential than the cathode, shown in figure 2。 In one shot more than ”red light frequency is premi, escape from the optoelectronic cathode surface by positive potential attracted the anode in photoelectric tube forming space， called the current stream。 Then if light intensity increas, the number of photons bombarded the cathode multiplied, unit of time to launch photoelectron number are also increasing, photo—current greatens。 In figure 2 shows circuit， current and resistance is the voltage drop across the only a function of light intensity relations， so as to achieve a photoelectric conversion. When the LTT optoelectronic cathode K, electronic escape from the cathode surface, and was the photoelectric anode is an electric current, power plants absorb deoxidization device in the load resistance - I, the voltage
