傳感器英文文獻(xiàn)翻譯-光電傳感器

1、傳感器英文文獻(xiàn)翻譯光電傳感器報(bào)告人 :業(yè)：師：Photoelectric sensorKey word: photoelectric effect photoelectric element photoelectric sensor classification sensor application characteristic s.Abstract: in the rapid development of science and technology in the modern society, mankind has into the rapidly changing informatio

2、n 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 listed in one of the priority to the developme

3、nt 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 structure, non-contact, high reliability, high

4、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 composition.Text:First, theoretical foundation -

5、photoelectric effectPhotoelectric 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 large enough electronic electronic will overcome bo

6、und from material surface and enter the outside space, which changes photoelectron materials, this kind of phenomenon become the conductivity of the photoelectric effectAccording to Einstein's photoelectron effect, photon is moving particles, each photon energy for hv (v for light frequency, h f

7、or 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 increase, increased energy part of the fetter, positive ions u

8、sed to overcome another part of converted into electronic energy. According to the law of conservation of energy:12m h -A2Type, 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 th

9、e 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

10、9;t 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 optical effects. It belongs

11、 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 corresponding cavities

12、. 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 according to the optoelectr

13、onics 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 light illuminate the pheno

14、menon 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 characteristicsAccording to the outside optoelectronics manufacturing optoelectronic dev

15、ices 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

16、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 increase h. When

17、 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 energyPhototubes normal work, anode p

18、otential 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 intensity increases, the nu

19、mber 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 c

20、onversion. 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 voltagePhototubes photoelectric characteristics fig.03 shows, from the graph

21、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 structure schematic dra

22、wing.圖 4 光電倍增結(jié)構(gòu)示意圖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 multiply electrode,. Usu

23、ally, 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 irradiation, cathodic K es

24、cape 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 acceleration, converged on

25、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 multiplication of rate is

26、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 good. Photomultiplier tu

27、bes 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 transparent window sealed in

28、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 is called dark current.2)

29、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 resistance added voltage and

30、 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 photoconductive resistance, lest than

31、 shown dotted lines of power consumption area5, photoelectric characteristics photoconductive resistance between the poles, light when voltage fixed the relationship between with bright current photoelectric characteristics. Called Photoconductive resistance photoelectric characteristics is nonlinea

32、r, 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 sensitivity called spectral ch

33、aracteristics. 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. Similarly, in stop light photo-curr

34、ent also need, over a period of time (down time) to restore the its dark current, this is photoconductive resistance delay characteristics. Photoconductive resistance rise response time and falling response time about 10-1 10-3s, namely the frequency response is 10Hz 1000Hz, visible photoconductive

35、resistance cannot be used in demand quick response occasion, this is one of the main photoconductive resistance shortcomings.8, and temperature characteristic photoconductive resistance by temperature affects greatly, temperature rise, dark current increase, reduced sensitivity, which is another pho

36、toconductive resistance shortcomings.9, frequency characteristic frequency characteristics refers to an external voltage and incident light, strong must be photo-current I and incident light modulation frequency, the relationship between the f, photoelectric diode is the frequency characteristic of

37、the photoelectric triode frequency characteristics, this is because of the photoelectric triode shot "yankees there capacitance and carrier base-combed need time's sake. By using the principle of the photoelectric efficiency of optoelectronics manufacturing frequency characteristics of the

38、worst, this is due to capture charge carriers and release charge need a certain time's sake.Three, photoelectric sensorsPhotoelectric sensor is through the light intensity changes into electrical signal changes to achieve control, its basic structure, it first figure 6 by measuring the change of

39、 change of converting the light signal, and then using photoelectric element further will light signals into electrical signal by photoelectric sensor general.Illuminant, optical path and optoelectronics. Three components of photoelectric detection method has high precision, fast response, non-conta

40、ct wait for an advantage, but measurable parameters of simple structure, sensors, form flexible, therefore, photoelectric sensor in the test and control is widely used.By photoelectric sensor generally is composed of three parts, they are divided into: transmitter and receiver and detection circuit

41、shown, as shown in figure 7, transmitter aimed at the target launch beam, the launch of the beam from semiconductor illuminant, general light emitting diode (LED), laser diode and infrared emission diode. Beam uninterrupted launch, or change the pulse width. Receivers have photoelectric diode, photo

42、electric triode, composed si-based ones. In front of the receiver, equipped with optical components such as lens and aperture, etc. In its back is detection circuit, it can filter out effective signal and the application of the signal. In addition, the structural components in photoelectric switch a

43、nd launch plate and optical fiber, triangle reflex plate is solid structure launch device. It consists of small triangle cone of reflective materials, can make a beam accurately reflected back from plate, with practical significance. It can be in with the scope of optical axis 0 to 25, make beams ch

44、ange launch Angle from a root almost after launch line, passes reflection or from the rotating polygon.some basic returns.圖7Photoelectric sensor is a kind of depend on is analyte and optoelectronics and light source, to achieve the relationship between the measured purpose, so the light source photo

45、electric sensor plays a very important role, photoelectric sensor power if a constant source, power is very important for design, the stability of the stability of power directly affect the accuracy of measurement, commonly used illuminant have the following kinds:1, leds is a change electric energy

46、 into light energy semiconductor devices. It has small volume, low power consumption, long life, fast response, the advantages of high mechanical strength, and can match and integrated circuits. Therefore, widely used in computer, instruments and automatic control equipment.2, silk light bulb that i

47、s one of the most commonly used illuminant, it has rich infrared light. If chosen optoelectronics, constitutes of infrared sensor sensitive colour filter can be added to the visible tungsten lamps, but only filter with its infrared does illuminant, such, which can effectively prevent other light int

48、erference.3, compared with ordinary light laser laser with energy concentration, directional good, frequency pure, coherence as well as good, is very ideal light sources. The light source, optical path and photoelectric device composition photoelectric sensor used in photoelectric detection, still m

49、ust be equipped with appropriate measurement circuit. The photoelectric effect to the measurement circuit of photoelectric element of widerange caused changes needed to convert the voltage or current. Different photoelectric element, the measurement circuit required is not identical also. Several se

50、miconductor introduces below optoelectronic devices commonly used measurement circuit.Semiconductor photoconductive resistance can through large current, be in so usually, need not equipped with amplifier. In the output power of demand is bigger, can use figure 8 shows circuit.Figure 9 (a) with temp

51、erature compensation given the photosensitive diode bridge type measuring circuit. When the incident light intensity slow change, the reverse resistance photosensitive diode is the slow change, the change of the temperature will cause the bridge output voltage, must compensate. Drift Picture a photo

52、sensitive diode as the test components, another into Windows, in neighboring bridge, the change of the temperature in the arms of the influence of two photosensitive diode, therefore, can eliminate the same output with temperature bridge road drift.Light activated triode incident light in work under

53、 low illumination, or hope to getbigger output power, also can match with amplifying circuit, as shown in figure 9 shows.Because even in the glare photosensitive batteries, maximum output voltage also only 0.6 V, still cannot make the next level 1 transistor have larger current output, so must add p

54、ositive bias, as shown in figure 9 (a) below. In order to reduce the transistor circuit impedance variations, base si-based ones to reduce as much as possible without light, when the reverse bias inherit in parallel a resistor si-based ones at both ends. Or like figure 9 (b) as shown by the positive

55、 ge diode produces pressure drop and test the voltage produced when exposed to light, make silicon tube e stack, b the voltage between actuators than 0.7 ,Vand conduction work. This kind of circumstance also can use silicon light batteries, as shown in figure 10 (c) below.Semiconductor photoelectric

56、 element of photoelectric circuit can also use integrated operational amplifier. Silicon photosensitive diode can be obtained by integrating op-amp larger output amplitude, as shown in figure 11 (a) below. When light is produced, the optical output voltage in order to guarantee photosensitive diode

57、is reverse biased, in its positive to add a load voltage. Figure 11. (b) give the photocell transform circuit, because the photoelectric si-based ones short-circuit current and illumination of a linear relationship between, so will it up in the op-amp is, inverse-phase input, using these two potenti

58、al difference between the characteristics of close to zero, can get better effect. In the picture shows conditions, the outputvoltageThe photoelectric element by flux the role of different made from the principle of optical measurement and control system is varied, press the photoelectric element (o

59、ptical measurement and control system) output nature, namely, can be divided into second analog photoelectric sensor and pulse (switch) photoelectric sensor. Analog photoelectric sensors will be converted into continuous variation of the measure, it is measured optical with a single value relations between analog photoelectric sensor. According to be measured (objects) method detection of target can be divided into transmission (absorption) type, diffuse type, shading type (beam resistance ge