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The definition of sensor and classification

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One, the high speed of the headway that the technology of definition information processing of sensor gains and microprocessor and computer technology develops, need to there is corresponding progress in the development respect of sensor. Microprocessor had received wide application in measure and controlling a system now. As the buildup of these systematic capacity, the front that collects a system as information is unit, the effect of sensor is mainer and mainer. Sensor already made the crucial part in automation system and robot technology, regard a structure in the system as composition, its importance becomes clearer and clearer. Most for broad sense ground, sensor is one kind can transform physical quantity or chemical quantity into facilitate the parts of an apparatus of the telegraphic name that use. International Electrotechnical Committee (IEC:IThe definition of NternationalElectrotechnicalCommittee) is: "Sensor is the component of the one buy before planting in surveying a system, it changes input variable into can offer metrical signal " . The view that waits according to Gopel is: "Sensor is to include to bear the weight of body and circuit connective sensing element " , and " sensor system is combination has some kind of information processing (imitate or number) the sensor of ability " . Sensor is a component of sensor system, it is the first col that signal be metricaled inputs. The principle block diagram of sensor system is shown at graph 1-1, the signal range that enters sensor is very small, and jumbly have interference signal and noise. To go to the lavatory subsequently processing process, want to become signal plastics the weaveform that has optimal character above all, still need to turn line sex sometimes, with etc by amplifier, filter circuit of a few imitate completes this work. Below certain circumstance, the one part of these circuit is with sensor component of direct look adjacent. The signal after figuration is changed into digital signal subsequently, input microprocessor. Germany and Russia scholar think sensor should be comprised by 2 parts, feel the circuit part of the sensing element part of signal be metricaled and initiative processing signal directly namely. Understand by this kind, sensor still included signal figuration implement circuit part. The function of sensor system basically depends on sensor, sensor changes the energy of some kind of form into the energy of another kind of form. Have two kinds of sensor: Of active with passive. Active sensor can transform form of a kind of energy directly another kind, the sources of energy that outside needing, receives or incentive source (consult graph 1-2(a)) . Active (A) and passive (the sensor of signal flow passive of B) sensor cannot change energy form directly, but it can control the energy that carries an input from another input or drive can the job that sensor assumes the specific character a certain object or process to be changed into the amount. Its " object " can be solid, liquid or gas, and their condition can be a static state, also can be dynamic (namely process) . After object character is quantified by changeover, can detect through a variety of means. The character of the object can be physical property, also can be chemistry. According to its job principle, sensor becomes object character or condition parameter changeover the electricity quantity that can determine, come out depart of this report signal next, send sensor system to try evaluation or designation. All sorts of physics effect and working mechanism are used at making the sensor of different function. Sensor can contact object be metricaled directly, also need not contact. The working mechanism that is used at sensor and effect type increase ceaselessly, the processing course that its include is increasingly perfect. Constant the function of sensor and mankind 5 old sensory photographs are likened to: Photosensitive sensor -- visual  sound quick sensor -- hearing is angry quick sensor -- olfactory  chemical sensor -- taste is pressed quick, sensor of Wen Min, fluid -- touch and contemporary sensor photograph are compared, human sentience is good much, but the sensory function that also a few sensor compare a person is advantageous, for example the mankind is felt without ability ultraviolet or infrared radiate, the feeling is less than gas of electromagnetism field, colorless dull to wait. To sensor set a lot of technology requirements, having a few is applicable to all type sensor, also have an applicable to specific type sensor special demand. The main demand that all needs in different situation in the light of the working principle of sensor and structure is: The stability of tall sensitivity interference rejection (not sensitive to noise)   linear adjusts easily (calibration is simple and easy) high reliability of   high accuracy does not have life of arrearage sex work to grow (durable sex)   but repeatability fights ageing tall answer rate to fight an environment to affect (hot, vibration, : Their changeover principle (the elementary physics that sensor works or chemical effect) ; Their utility; Their output signal type and the material that make them and craft. According to sensor job principle, can dividing what for physical sensor and chemical sensor the classified physics sensor of principle of job of 2 kinds of big sensor applies is physical effect, such as piezoelectric effect, magnetism causes adjustable appearance, report of ionization, polarization, pyroelectricity, photoelectricity, magnetism is equivalent should. The little change of the semaphore that be measured becomes changeover telegraphic name. Chemical sensor includes those to be causal sensor with the phenomenon such as reaction of chemical adsorption, electrochemistry, the little change of the semaphore that be measured also becomes changeover telegraphic name. Some sensor both neither can differentiate physics kind, also cannot differentiate for chemistry kind. Most sensor is run for the foundation with physical principle. Issue of chemical sensor technology is more, for example dependability problem, the possibility that dimensions produces, price issue, solved this kind of difficult problem, the application of chemical sensor will have tremendous growth. The applied domain of common sensor and working principle rank are expressed 1.

1. According to its utility, sensor can classify for: Pressure quick and Li Min sensor of sensor  position sensor of  specific power consumption of sensor of face of     fluid  heats up sensor of     speed quick sensor of acceleration of sensor     sensor of  ray radiate     is oscillatory magnetism of   of sensor   of sensor  Shi Min quick sensor  is angry quick sensor.   of      outputs signal to be able to be sensor cent the standard with its: Imitate sensor -- the blame that is measured electricity quantity is changed into imitate telecommunication date. Sensor of number of   of      -- the transition of blame electricity volume that will be measured outputs signal into the number (include to be mixed directly indirect changeover) . Sensor of number of bear of   of      -- the output that changes the semaphore that is measured into frequency signal or short period signal (include) of direct or indirect changeover. Sensor of switch of   of      -- when the signal that should be measured reachs a certain specific threshold value, sensor outputs the low n of a set or tall n signal accordingly.    falls in the action of outside element, all material can be made corresponding, the reaction that has diagnostic sex. Those the most sensitive to outside action data in them, namely those stuff that have functional character, be used to the sensing element of the sensor that make. Set out from the material viewpoint of place application can divide sensor into following a few kinds: (1) separates mixture of  of pottery and porcelain of polymer  of  of metal of   of      according to the category that its use data   of   of      (the physical property that 2) presses material divides dielectric of  of   conductor   of   of   of   of  of material of  semiconductor  magnetism (, can reduce is undermentioned 3 direction:   of   of      (1) explores new phenomenon, effect and reaction in known material, make they can get be used actually in sensor technology next.   of   of      (the material with 2) new exploration, apply those foregone phenomena, effect and reaction to improve sensor technology.   of   of      (new phenomenon of the exploration on the foundation that 3) is studying to new profile expects, new effect and reaction, try in sensor technology specific carry out. The progress of manufacturing industry of    contemporary sensor depends on the new data that is used at sensor technology and the development intensity of sensing element. The basic trend that sensor develops is the application with semiconductor and medium material is close and associated. Express 1.

2 in gave out a few can be used at sensor technology, the material that can change energy form.   of      according to its workmanship, can distinguish sensor for: Compositive sensor  is filmy sensor of sensor  thick film sensor of  pottery and porcelain is compositive sensor is the production that uses a level the engineering technology of silicon radical semiconductor integrated circuit makes. Still will use at the first treatment to be measured normally the partial circuit of signal is compositive also go up in same chip.    filmy sensor is to pass deposit to be in medium underlay (substrate) go up, the film of corresponding and sensitive data forms. When using mixture technology, can make partial circuit likewise go up in this substrate. Sensor of    thick film is the oar material that uses relevant data, besmear Fu is in radical of pottery and porcelain piece on make, base piece normally Al2O3 is made, have heat treatment next, thickening film figuration. The technology of pottery and porcelain that sensor of pottery and porcelain uses a level or its some kind of varietal craft (sol - gel) production. After    finishs proper preliminary sex to operate, already the component of figuration undertakes agglomeration in high temperature. Thick film and sensor of pottery and porcelain have a lot of collective character between these 2 kinds of craft, in some way, one kind when can think thick film craft is craft of pottery and porcelain changes model. Every kinds of engineering technology has  from already advantage and inadequacy. The capital that needs as a result of research, development and manufacturing place is devoted and inferior, and the reason such as the tall stability of sensor parameter, use pottery and porcelain and thick film sensor more reasonable. CNC Milling