1、传感器英文文献翻译光电传感器传感器英文文献翻译-光电传感器光电传感器报告人: 学 号: 专 业: 老 师: 2011年 6月 2日 Photoelectric sensor Key word: photoelectric effect photoelectric element photoelectric sensor classification sensor application characteristics . Abstract: in the rapid development of science and technology in the modern society, man
2、kind 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 present our country has put detection techniques l
3、isted in one of the priority to the development of science and technology. Because of microelectronics technology, photoelectric semiconductor technology, optical fiber technology and grating technical development makes the application of the photoelectric sensor is growing. The sensor has simple st
4、ructure, non-contact, high reliability, high precision, measurable parameters and quick response 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 comp
5、osition. Text: First, theoretical foundation - photoelectric effect Photoelectric effect generally have the photoelectric effect, optical effect, light born volts effect. The light shines in photoelectric material, according to the electronic absorption material surface energy, if absorbed energy la
6、rge 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 According to Einsteins photoelectron effect, photon is moving particles, each pho
7、ton energy for hv (v for light frequency, h for Plancks 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 increase, increased en
8、ergy part of the fetter, positive ions used to overcome another part of converted into electronic energy. According to the law of conservation of energy: 12 m,h,-A2 Type, m for electronic quality, v for electronic escaping the velocity, A microelectronics the work done. From the type that will make
9、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
10、 matter how the light intensity, wont produce photoelectron launch, this frequency limit called red limit. The corresponding 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 opti
11、cal effects. It belongs to the photoelectric effect within. When light is, if in semiconductor electronic energy big with semiconductor 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
12、 corresponding cavities. Electronics, cavitation remained in semiconductor, and participate in electric conductive outside formed under the current role. In addition to metal outer, most insulators and semiconductor have photoelectric effect, particularly remarkable, semiconductor optical effect acc
13、ording to the optoelectronics manufacturing incident light inherent frequency, when light resistance in light, its conductivity increases, 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 li
14、ght illuminate the phenomenon is called light emf, born volts effect on the effect of photoelectric devices have made si-based ones, photoelectric diode, control thyristor and optical couplers, etc. Second, optoelectronic components and characteristics According to the outside optoelectronics manufa
15、cturing 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 me
16、tal 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 electro
17、nic energy increase 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 initial kinetic energy Pho
18、totubes normal work, anode potential than the cathode, shown in figure 2. In one shot more than red light frequency is premise, escape from the optoelectronic cathode surface by positive potential attracted the anode in photoelectric tube forming space, called the current stream. Then if light inten
19、sity increases, 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 ach
20、ieve 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 Phototubes photoelectric characteristics fig.03
21、 shows, from the graph in flux knowable, not too big, photoelectric basic characteristics is a straight line. 2. Photoelectric times had the sensitivity of vacuum tube due to low, so with people developed has magnified the photomultiplier tubes photo-current ability. Figure 4 is photomultiplier tube
22、 structure schematic drawing. 图4光电倍增结构示意图 From the graph can see photomultiplier tubes also have A cathode K and an anode A, and phototubes different is in its between anode and cathode set up several secondary emission electrodes, D1, D2 and D3. They called the first multiply electrode, the second
23、multiply electrode,. Usually, double electrode for 10 15 levels. Photomultiplier tubes work between adjacent electrode, keeping a certain minimum, including the cathode potential potentials, each multiply electrode potential filtering increases, the anode potential supreme. When the incident light i
24、rradiation, cathodic K escape from the optoelectronic cathode multiplied by first accelerated, by high speed electrode D1 bombarded caused secondary electron emission, D1, an incident can generate multiple secondary electron photonics, D1 emit of secondary electron was D1, D2 asked electric field ac
25、celeration, converged on D2 and again produce secondary electron emission. So gradually produce secondary electron emission, make electronic increased rapidly, these electronic finally arrived at the anode, form a larger anode current. If a n level, multiply electrodes at all levels for sigma, the m
26、ultiplication of rate is the multiplication of photomultiplier tubes can be considered sigma n rate, therefore, photomultiplier tube has high sensitivity. In the output current is less than 1mA circumstances, it in a very wide photoelectric properties within the scope of the linear relationship with
27、 good. Photomultiplier tubes this characteristic, make it more for light measurement. 3 and photoconductive resistance photoconductive resistance within the working principle is based on the photoelectric effect. In semiconductor photosensitive material ends of mount electrode lead, it contains tran
28、sparent window sealed in the tube and shell element photoconductive resistance. Photoconductive resistance properties and parameters are: 1) dark resistance photoconductive resistance at room temperature, total dark conditions stable resistance called dark resistance, at the current flow resistance
29、is called dark current. 2) light resistance photoconductive resistance at room temperature and certain lighting conditions stable resistance measured, right now is called light resistance of current flow resistance is called light current. 4, volt-ampere characteristics of both ends photoconductive
30、resistance added voltage and current flows through photoconductive resistance of the relationship between called volt-ampere characteristics shown, as shown in figure 5. From the graph, the approximate linear volt-ampere characteristics that use should be limited, but when the voltage ends photocond
31、uctive resistance, lest than shown dotted lines of power consumption area 5, photoelectric characteristics photoconductive resistance between the poles, light when voltage fixed the relationship between with bright current photoelectric characteristics. Called Photoconductive resistance photoelectri
32、c characteristics is nonlinear, this is one of the major drawback of photoconductive resistance. 6, spectral characteristics is not the same incident wavelength, the sensitivity of photoconductive resistance is different also. Incidence wavelength and photodetector the relationship between relative
33、sensitivity called spectral characteristics. When used according to the wavelength range by metering, choose different material photoconductive resistance. 7, response time by photoconductive resistance after photo-current need light, over a period of time (time) rise to reach its steady value. Simila
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