光電傳感器(中英文對照版)

PhotoelectricsensorKeyword:photoelectriceffectphotoelectricelementphotoelectricsensorclassificationsensorapplicationcharacteristics.Abstract:intherapiddevelopmentofscienceandtechnologyinthemodernsociety,mankindhasintotherapidlychanginginformationera,peopleindailylife,theproductionprocess,relymainlyonthedetectionofinformationtechnologybyacquiring,screeningandtransmission,toachievethebrakecontrol,automaticadjustment,atpresentourcountryhasputdetectiontechniqueslistedinoneoftheprioritytothedevelopmentofscienceandtechnology.Becauseofmicroelectronicstechnology,photoelectricsemiconductortechnology,opticalfibertechnologyandgratingtechnicaldevelopmentmakestheapplicationofthephotoelectricsensorisgrowing.Thesensorhassimplestructure,non-contact,highreliability,highprecision,measurableparametersandquickresponseandmoresimplestructure,formetc,andflexibleinautomaticdetectiontechnology,ithasbeenwidelyappliedinphotoelectriceffectasthetheoreticalbasis,thedevicebyphotoelectricmaterialcomposition.Text:First,theoreticalfoundation-photoelectriceffectPhotoelectriceffectgenerallyhavethephotoelectriceffect,opticaleffect,lightbornvoltseffect.Thelightshinesinphotoelectricmaterial,accordingtotheelectronicabsorptionmaterialsurfaceenergy,ifabsorbedenergylargeenoughelectronicelectronicwillovercomeboundfrommaterialsurfaceandentertheoutsidespace,whichchangesphotoelectronmaterials,thiskindofphenomenonbecometheconductivityofthephotoelectriceffectAccordingtoEinstein'sphotoelectroneffect,photonismovingparticles,eachphotonenergyforhv(vforlightfrequency,hforPlanck'sconstant,h=6.63*10-34J/HZ),thusdifferentfrequencyofphotonshavedifferentenergy,light,thehigherthefrequency,thephotonenergyisbigger.Assumingalltheenergyphotonstophotons,electronicenergywillincrease,increasedenergypartofthefetter,positiveionsusedtoovercomeanotherpartofconvertedintoelectronicenergy.Accordingtothelawofconservationofenergy:Type,mforelectronicquality,vforelectronicescapingthevelocity,Amicroelectronicstheworkdone.Fromthetypethatwillmaketheoptoelectroniccathodesurfaceescapethenecessaryconditionsareh>A.Duetothedifferentmaterialshavedifferentescaping,soreactivetoeachkindofcathodematerials,incidentlighthasacertainfrequencyisrestricted,whenthefrequencyofincidentlightunderthisfrequencylimit,nomatterhowthelightintensity,won'tproducephotoelectronlaunch,thisfrequencylimitcalled"redlimit".Thecorrespondingwavelengthfortype,cforthespeedoflight,Areactiveforescaping.Whenisthesun,itselectronicenergy,absorbtheresistivityreduceconductivephenomenoncalledopticaleffects.Itbelongstothephotoelectriceffectwithin.Whenlightis,ifinsemiconductorelectronicenergybigwithsemiconductorofforbiddenbandwidth,theelectronicenergyfromthevalencebandjumpintotheconductionband,form,andatthesametime,thevalencebandelectronicleftthecorrespondingcavities.Electronics,cavitationremainedinsemiconductor,andparticipateinelectricconductiveoutsideformedunderthecurrentrole.Inadditiontometalouter,mostinsulatorsandsemiconductorhavephotoelectriceffect,particularlyremarkable,semiconductoropticaleffectaccordingtotheoptoelectronicsmanufacturingincidentlightinherentfrequency,whenlightresistanceinlight,itsconductivityincreases,resistancedrops.Thelightintensityisstrong,itsvalue,ifthesmaller,itsresistancetostoplightbacktotheoriginalvalue.Semiconductorproducedbylightilluminatethephenomenoniscalledlightemf,bornvoltseffectontheeffectofphotoelectricdeviceshavemadesi-basedones,photoelectricdiode,controlthyristorandopticalcouplers,etc.Second,optoelectroniccomponentsandcharacteristicsAccordingtotheoutsideoptoelectronicsmanufacturingoptoelectronicdeviceshavephotoelectron,inflatablephototubesandphotoelectrictimesoncetube.1.Phototubesphototubesarevariousandtypicalproductsarevacuumphototubesandinflatablephototubes,lightitsappearanceandstructureasshowninfigure1shows,madeofcylindricalmetalhalfcathodicKandislocatedinthewirescathodicaxisofanodeinApackageofsmokeintothevacuum,whenincidentlightwithinglassshellinthecathode,illuminateAsinglephotontookallofitsenergytransfertothecathodematerialsAfreeelectrons,soastomakethefreedomelectronicenergyincreaseh.Whenelectronsgainenergymorethanescapeofcathodematerials,itreactiveAmetalsurfaceconstraintscanovercomeescape,formelectronemission.Thiskindofelectroniccalledoptoelectronics,optoelectronicescapingthemetalsurfaceforafterinitialkineticenergyPhototubesnormalwork,anodepotentialthanthecathode,showninfigure2.Inoneshotmorethan"redlightfrequencyispremise,escapefromtheoptoelectroniccathodesurfacebypositivepotentialattractedtheanodeinphotoelectrictubeformingspace,calledthecurrentstream.Theniflightintensityincreases,thenumberofphotonsbombardedthecathodemultiplied,unitoftimetolaunchphotoelectronnumberarealsoincreasing,photo-currentgreatens.Infigure2showscircuit,currentandresistanceisthevoltagedropacrosstheonlyafunctionoflightintensityrelations,soastoachieveaphotoelectricconversion.WhentheLTToptoelectroniccathodeK,electronicescapefromthecathodesurface,andwasthephotoelectricanodeisanelectriccurrent,powerplantsabsorbdeoxidizationdeviceintheloadresistance-I,thevoltagePhototubesphotoelectriccharacteristicsfig.03shows,fromthegraphinfluxknowable,nottoobig,photoelectricbasiccharacteristicsisastraightline.triodeshot"yankeestherecapacitanceandcarrierbase-combedneedtime'ssake.Byusingtheprincipleofthephotoelectricefficiencyofoptoelectronicsmanufacturingfrequencycharacteristicsoftheworst,thisisduetocapturechargecarriersandreleasechargeneedacertaintime'ssake.Three,photoelectricsensorsPhotoelectricsensoristhroughthelightintensitychangesintoelectricalsignalchangestoachievecontrol,itsbasicstructure,itfirstfigure6bymeasuringthechangeofchangeofconvertingthelightsignal,andthenusingphotoelectricelementfurtherwilllightsignalsintoelectricalsignalbyphotoelectricsensorgeneral.Illuminant,opticalpathandoptoelectronics.Threecomponentsofphotoelectricdetectionmethodhashighprecision,fastresponse,non-contactwaitforanadvantage,butmeasurableparametersofsimplestructure,sensors,formflexible,therefore,photoelectricsensorinthetestandcontroliswidelyused.Byphotoelectricsensorgenerallyiscomposedofthreeparts,theyaredividedinto:transmitterandreceiveranddetectioncircuitshown,asshowninfigure7,transmitteraimedatthetargetlaunchbeam,thelaunchofthebeamfromsemiconductorilluminant,generallightemittingdiode(LED),laserdiodeandinfraredemissiondiode.Beamuninterruptedlaunch,orchangethepulsewidth.Receivershavephotoelectricdiode,photoelectrictriode,composedsi-basedones.Infrontofthereceiver,equippedwithopticalcomponentssuchaslensandaperture,etc.Initsbackisdetectioncircuit,itcanfilterouteffectivesignalandtheapplicationofthesignal.Inaddition,thestructuralcomponentsinphotoelectricswitchandlaunchplateandopticalfiber,trianglereflexplateissolidstructurelaunchdevice.Itconsistsofsmalltriangleconeofreflectivematerials,canmakeabeamaccuratelyreflectedbackfromplate,withpracticalsignificance.Itcanbeinwiththescopeofopticalaxis0to25,makebeamschangelaunchAnglefromarootalmostafterlaunchline,passesreflectionorfromtherotatingpolygon.somebasicreturns.圖7Photoelectricsensorisakindofdependonisanalyteandoptoelectronicsandlightsource,toachievetherelationshipbetweenthemeasuredpurpose,sothelightsourcephotoelectricsensorplaysaveryimportantrole,photoelectricsensorpowerifaconstantsource,powerisveryimportantfordesign,thestabilityofthestabilityofpowerdirectlyaffecttheaccuracyofmeasurement,commonlyusedilluminanthavethefollowingkinds:1,ledsisachangeelectricenergyintolightenergysemiconductordevices.Ithassmallvolume,lowpowerconsumption,longlife,fastresponse,theadvantagesofhighmechanicalstrength,andcanmatchandintegratedcircuits.Therefore,widelyusedincomputer,instrumentsandautomaticcontrolequipment.2,silklightbulbthatisoneofthemostcommonlyusedilluminant,ithasrichinfraredlight.Ifchosenoptoelectronics,constitutesofinfraredsensorsensitivecolourfiltercanbeaddedtothevisibletungstenlamps,butonlyfilterwithitsinfrareddoesilluminant,such,whichcaneffectivelypreventotherlightinterference.3,comparedwithordinarylightlaserlaserwithenergyconcentration,directionalgood,frequencypure,coherenceaswellasgood,isveryideallightsources.Thelightsource,opticalpathandphotoelectricdevicecompositionphotoelectricsensorusedinphotoelectricdetection,stillmustbeequippedwithappropriatemeasurementcircuit.Thephotoelectriceffecttothemeasurementcircuitofphotoelectricelementofwiderangecausedchangesneededtoconvertthevoltageorcurrent.Differentphotoelectricelement,themeasurementcircuitrequiredisnotidenticalalso.Severalsemiconductorintroducesbelowoptoelectronicdevicescommonlyusedmeasurementcircuit.Semiconductorphotoconductiveresistancecanthroughlargecurrent,beinsousually,neednotequippedwithamplifier.Intheoutputpowerofdemandisbigger,canusefigure8showscircuit.Figure9(a)withtemperaturecompensationgiventhephotosensitivediodebridgetypemeasuringcircuit.Whentheincidentlightintensityslowchange,thereverseresistancephotosensitivediodeistheslowchange,thechangeofthetemperaturewillcausethebridgeoutputvoltage,mustcompensate.DriftPictureaphotosensitivediodeasthetestcomponents,anotherintoWindows,inneighboringbridge,thechangeofthetemperatureinthearmsoftheinfluenceoftwophotosensitivediode,therefore,caneliminatethesameoutputwithtemperaturebridgeroaddrift.Lightactivatedtriodeincidentlightinworkunderlowillumination,orhopetogetbiggeroutputpower,alsocanmatchwithamplifyingcircuit,asshowninfigure9shows.Becauseevenintheglarephotosensitivebatteries,maximumoutputvoltagealsoonly0.6V,stillcannotmakethenextlevel1transistorhavelargercurrentoutput,somustaddpositivebias,asshowninfigure9(a)below.Inordertoreducethetransistorcircuitimpedancevariations,basesi-basedonestoreduceasmuchaspossiblewithoutlight,whenthereversebiasinheritinparallelaresistorsi-basedonesatbothends.Orlikefigure9(b)asshownbythepositivegediodeproducespressuredropandtestthevoltageproducedwhenexposedtolight,makesilicontubeestack,bthevoltagebetweenactuatorsthan0.7V,andconductionwork.Thiskindofcircumstancealsocanusesiliconlightbatteries,asshowninfigure10(c)below.Semiconductorphotoelectricelementofphotoelectriccircuitcanalsouseintegratedoperationalamplifier.Siliconphotosensitivediodecanbeobtainedbyintegratingop-amplargeroutputamplitude,asshowninfigure11(a)below.Whenlightisproduced,theopticaloutputvoltageinordertoguaranteephotosensitivediodeisreversebiased,initspositivetoaddaloadvoltage.Figure11.(b)givethephotocelltransformcircuit,becausethephotoelectricsi-basedonesshort-circuitcurrentandilluminationofalinearrelationshipbetween,sowillitupintheop-ampis,inverse-phaseinput,usingthesetwopotentialdifferencebetweenthecharacteristicsofclosetozero,cangetbettereffect.Inthepictureshowsconditions,theoutputvoltageThephotoelectricelementbyfluxtheroleofdifferentmadefromtheprincipleofopticalmeasurementandcontrolsystemisvaried,pressthephotoelectricelement(opticalmeasurementandcontrolsystem)outputnature,namely,canbedividedintosecondanalogphotoelectricsensorandpulse(switch)photoelectricsensor.Analogphotoelectricsensorswillbeconvertedintocontinuousvariationofthemeasure,itismeasuredopticalwithasinglevaluerelationsbetweenanalogphotoelectricsensor.Accordingtobemeasured(objects)methoddetectionoftargetcanbedividedintotransmission(absorption)type,diffusetype,shadingtype(beamresistancegears)threecategories.So-calledtransmissionstylemeanstheobjecttobetestedinopticalpathinconstantlightsource,thelightenergythroughthings,partofbeingmeasuredbyabsorption,transmittedlightontophotoelectricelement,suchasmeasuredliquid,gastransparencyandphotoelectricBiSeJietc;speed.gratifyingTheso-calleddiffusestylemeanstheconstantlightbythelightontotheanalytefromtheobjecttobetested,andprojectedontosurfacesreflectonafteroptoelectronicdevices,suchasphotoelectriccolorimetricthermometerandlightgaugeetc;Theso-calledshadingstylemeansthewhenilluminantissuedbythefluxoflightanalytecoveredbyapartJingoptoelectronics,makeprojectiononthefluxchange,changetheobjecttobetestedandextentofthepositionwiththelightpath,suchasvibrationmeasurement,thesizemeasurement;Andinpulsephotoelectricsensorinthesensors,photoelectricelementacceptableopticalsignalisintermittentchange,thereforephotoelectricelementinswitchworkofthestate,thecurrentoutputitisusuallyonlytwosteadystateofthesignal,thepulseformusedforphotoelectriccountingandphotoelectricspeedmeasurementandsoon.Andinfraredphotoelectricsensorclassificationandworkingwaygenerallyhavethefollowingkinds:1,groovephotoelectricsensorputalightemitterandareceiverinaslotface-to-faceoutfitareonoppositesidesofthephotoelectricgroove.Lighteremitsinfraredlightorvisiblelight,andinunimpededcaseslightreceptorscanreceivelight.Butwhentestedobjectsfromslotzhongtongobsolete,lightoccluded,photoelectricswitchesandaction.Outputaswitchcontrolsignal,cutofforconnectloadcurrent,thuscompletingacontrolmovement.Grooveswitchistheoverallofdetectiondistancebecausegeneralstructurelimitsonlyafewcentimeters.2,DuiShetypeoptoelectronicsensorifyouputlighterandreceivelightisseparated,canmakethedetectiondistanceincrease.ByalighterandaninboxlightsensorintoaphotoelectricswitchiscalledDuiSheseparatephotoelectricswitches,referredtoDuiShephotoelectricswitch.Itsdetectiondistancecanreachafewmetersandevenadozenmeters.Whenusinglight-emittingdeviceandreceivelightdeviceareinstalledintestobjectthroughthepathofthesides,testobjectbyblockinglightpath,acceptlightimplementactionoutputaswitchcontrolsignals.3,reflexplate.itphotoelectricswitchlight-emittingdevicetypeandreceivelightdeviceintothesamedeviceinside,initsfrontpackareflexplate.theusingthereflectionprincipleofcompletephotoelectriccontrolfunctioniscalledreflexplate.itreflex(orreflectorreflex)photoelectricswitch.Undernormalcircumstances,lighterthelightreflectedbyreflexplate.itisreceivedbyacceptlight;Oncethelightpathbetestobjecttoblock,acceptlight,thelightisnotreceivephotoelectricswitchisaction,outputaswitchcontrolsignals.4,diffusionreflectivephotoelectricswitchesitsdetectionheadwithalighterandalsoaninboxlightware,butnoreflexplate.itahead.Normallylighterforthelightcollectlightisnotfound.Whentestobjectbyblockingthelight,andthelightreflectedlight,receivepartimplementreceivedlightsignals,outputaswitchsignals.Four,I'mtheideaofphotoelectricsensorWiththedevelopmentofscienceandtechnologypeopleonmeasuringaccuracyhadthehigherrequest,thishaspromptedthepacewithTheTimesphotoelectricsensorhaveupdated,improvethemainmeansphotoelectricsensorperformanceistheapplicationofnewmaterials,newtechnologymanufacturingperformanceismoresuperiorphotoelectricelement.Forexample,todaytheprototypeofthephotoelectricsensorisasmallmetalcylindricalequipment,withacalibrationlens,transmitterintoreceiverfocusedlight,thereceiveroutofcabletothedevicegotavacuumtubeamplifiersinmetalcylinderontheincandescentlightbulbinsideasmallasthelightsourceastrongincandescentlampsensor.Duetothesensorvariousdefectsexistinginthefields,graduallyfaded.Toappear,becauseofitoffiberofexcellentperformance,thenappearedwithsensorssupportingtheuseofopticalpassivecomponents,anotherfiberwithoutanyinterferenceofelectromagneticsignal,andcanmakethesensoroftheelectroniccomponentsandotherelectricaldisturbanceinisolation.Haveapieceofplasticopticalfibercoreorglasslightcore,lightoutsideametalliccoreskinsandbreadthislayermetalcorticaldensitylowerthanlightcore,solow,thebeamrefractioninthetwomaterialsaccordingtotheborder(incidentAnglewithinacertainrange,reflected),isall.Basedonopticalprinciple,allbeamscanbemadebyopticalfibertotransmission.TwoincidentbeamAngleinanAngle(alongthefiberlengthdirectionwithin)bymultiplereflectionsfromtheotherendafterinjection,anotherincidentanglesthanaccepttheincidentlightinmetalskin,loss.ThisacceptAnglewithinthebiggestincidentAnglethantwotimes,thisisbecausefiberslightlylargerfromairintodensitylargerfibermaterialshittingmayhaveaslightrefraction.Inlightoftheopticalfibertransmissionfrominsidetheinfluenceoffiberbending(whethermorethanbendingradiusminimalbendingradius).Mostopticalfiberisflexible,easytoinstallinthenarrowspace.Photoelectricsensorisakindofnon-contactmeasurementsmallelectronicmeasurementequipment,relyondetectitsreceivesthelightintensitychange,toachievemeasurementpurposes,andit'salsoavulnerabletoexternaldisturbanceandlosethemeasurementaccuracyofthedevice.Whenbebeingdesignedsobesidesthechoiceoptoelectroniccomponents,stillmustsetGSCCsignalandtemperaturecompensatingmeasuresusedtoweakenoreliminatetheimpactofthesefactors.Photoelectricsensormustpassalightmodulation,likeradiowavesoflightmodulationofsendsandreceives,theradiotoastation,canignoreotherradiosignalsensorswithoutmodulationlong-focal-lengthonlythroughtheuseofmechanicalshielded,scenesthatreceivertransmitteronlycanreceivetheemissionoflight,canmakeitsenergybecomesveryhigh.Incontrast,throughmodulationtransceiverscanignoreambientlight,onlytoownlightorwiththesamemodulationfrequenciesoflightwithoutmodulationresponse.Thesensorusedtotesttheinfraredraysoraroundtheradiation,ifjustbakedredbottle,inthisapplicationsituationifuseothersensor,maybeincorrectactions.Photoelectricsensorduetonon-contact,highreliability,etc,andtochangeinmeasurement,damagetheobjecttobetestedSosinceitsinventioninfieldssinceplayasignificantrole,atpresentithasbeenwidelyusedinmeasuringmechanicalquantity,thermalquantity,weight,intelligentvehiclesystemintoetc.Nowitinpowersystemautomaticallygriddeviceplaysaveryimportantrole,becausegeneratorinputpowergridoperationoftenUSESaccuratewithlaw,mustmeet:three-phaselinesequenceisconsistent,frequency,phaseagreeunanimously,voltageamplitudeequal,oneoftheconditionsinsystemdesignhasbeensatisfied,afterthreeconditionsmustalsomeettogrid,ofcourse,artificiallygridismoredifficult,photoelectricgridiseasier.Thedevelopmentoftimes,scienceandtechnologyintheupdate,photoelectricsensortypesareincreasingandapplicationdomainmoreandmorewidely,suchasarecentkindofinfraredalreadyinintelligentvehicleelectricalsensorsintotheapplication,oneofwhichhadbasedoninfraredsensoristhecoreofintelligentvehicle,reflectivetypeinfraredsensorusingreflexinfraredsensordesignpathdetectionmoduleandspeedmonitoringmodule;Anothermethodbasedoninfraredsensorusingthecartracingistocollectinfraredsensordata.Photoelectricsensorhascannotbereplacedbyothersensorssuperiority,soitdevelopmentforegroundisverygood,theapplicationwillalsobecomemorewidespread.光電傳感器關(guān)鍵字：光電效應(yīng)光電元件光電特性傳感器分類傳感器應(yīng)用摘要：在科學(xué)技術(shù)高速發(fā)展的現(xiàn)代社會中，人類已經(jīng)入瞬息萬變的信息時代，人們在日常生活，生產(chǎn)過程中，主要依靠檢測技術(shù)對信息經(jīng)獲取、篩選和傳輸，來實現(xiàn)制動控制，自動調(diào)節(jié)，目前我國已將檢測技術(shù)列入優(yōu)先發(fā)展的科學(xué)技術(shù)之一。由于微電子技術(shù)，光電半導(dǎo)體技術(shù)，光導(dǎo)纖維技術(shù)以及光柵技術(shù)的發(fā)展，使得光電傳感器的應(yīng)用與日俱增。這種傳感器具有結(jié)構(gòu)簡單、非接觸、高可靠性、高精度、可測參數(shù)多、反應(yīng)快以及結(jié)構(gòu)簡單,形式靈活多樣等優(yōu)點，在自動檢測技術(shù)中得到了廣泛應(yīng)用，它一種是以光電效應(yīng)為理論基礎(chǔ)，由光電材料構(gòu)成的器件。正文：一、理論基礎(chǔ)——光電效應(yīng)光電效應(yīng)一般有外光電效應(yīng)、光導(dǎo)效應(yīng)、光生伏特效應(yīng)。光照在照在光電材料上，材料表面的電子吸收的能量，若電子吸收的能量足夠大是，電子會克服束縛脫離材料表面而進(jìn)入外界空間，從而改變光電子材料的導(dǎo)電性，這種現(xiàn)象成為外光電效應(yīng)根據(jù)愛因斯坦的光電子效應(yīng)，光子是運動著的粒子流，每種光子的能量為hv(v為光波頻率，h為普朗克常數(shù)，h＝6.63*10-34J/HZ)，由此可見不同頻率的光子具有不同的能量，光波頻率越高，光子能量越大。假設(shè)光子的全部能量交給光子，電子能量將會增加，增加的能量一部分用于克服正離子的束縛，另一部分轉(zhuǎn)換成電子能量。根據(jù)能量守恒定律：式中，m為電子質(zhì)量,v為電子逸出的初速度,A微電子所做的功。由上式可知，要使光電子逸出陰極表面的必要條件是h>A。由于不同材料具有不同的逸出功，因此對每一種陰極材料，入射光都有一個確定的頻率限，當(dāng)入射光的頻率低于此頻率限時，不論光強多大，都不會產(chǎn)生光電子發(fā)射，此頻率限稱為“紅限”。相應(yīng)的波長為式中，c為光速，A為逸出功。當(dāng)受到光照射時，吸收電子能量，其電阻率降低的導(dǎo)電現(xiàn)象稱為光導(dǎo)效應(yīng)。它屬于內(nèi)光電效應(yīng)。當(dāng)光照在半導(dǎo)體上是，若電子的能量大與半導(dǎo)體禁帶的能級寬度，則電子從價帶躍遷到導(dǎo)帶，形成電子，同時，價帶留下相應(yīng)的空穴。電子、空穴仍留在半導(dǎo)體內(nèi)，并參與導(dǎo)電在外電場作用下形成的電流。除金屬外，多數(shù)絕緣體和半導(dǎo)體都有光電效應(yīng)，半導(dǎo)體尤為顯著，根據(jù)光導(dǎo)效應(yīng)制造的光電元件有固有入射光頻率，當(dāng)光照在光電阻上，其導(dǎo)電性增強，電阻值下降。光強度愈強，其阻值愈小，若停止光照，其阻值恢復(fù)到原阻值。半導(dǎo)體受光照射產(chǎn)生電動勢的現(xiàn)象稱為光生伏特效應(yīng)，據(jù)此效應(yīng)制造的光電器件有光電池，光電二極管，管控晶閘管和光耦合器等。二、光電元件及特性根據(jù)外光電元件制造的光電元件有光電子，充氣光電管和光電倍曾管。1.光電管光電管的種類繁多，典型的產(chǎn)品有真空光電管和充氣光電管，光它的外形和結(jié)構(gòu)如圖1所示，半圓筒形金屬片制成的陰極K和位于陰極軸心的金屬絲制成的陽極A封裝在抽成真空的玻殼內(nèi)，當(dāng)入射光照射在陰極上時，單個光子就把它的全部能量傳遞給陰極材料中的一個自由電子，從而使自由電子的能量增加h。當(dāng)電子獲得的能量大于陰極材料的逸出功A時，它就可以克服金屬表面束縛而逸出，形成電子發(fā)射。這種電子稱為光電子，光電子逸出金屬表面后的初始動能為光電管正常工作時，陽極電位高于陰極，如圖2所示。在人射光頻率大于“紅限”的前提下，從陰極表面逸出的光電子被具有正電位的陽極所吸引，在光電管內(nèi)形成空間電子流，稱為光電流。此時若光強增大，轟擊陰極的光子數(shù)增多，單位時間內(nèi)發(fā)射的光電子數(shù)也就增多，光電流變大。在圖2所示的電路中，電流和電阻只上的電壓降就和光強成函數(shù)關(guān)系，從而實現(xiàn)光電轉(zhuǎn)換。當(dāng)光線照射到光電陰極K上時，電子從陰極表面逸出，并被光電陽極的正電廠吸收，外電路產(chǎn)生電流I，在負(fù)載電阻上的電壓光電管的光電特性如圖3所示，從圖中可知，在光通量不太大時，光電特性基本是一條直線。圖3光電管的光電特性圖2光電管測量電路圖1光電光結(jié)構(gòu)示意圖圖3光電管的光電特性圖2光電管測量電路圖1光電光結(jié)構(gòu)示意圖2.光電倍曾管由于真空光電管的靈敏度低，因此人們研制了具有放大光電流能力的光電倍增管。圖4是光電倍增管結(jié)構(gòu)示意圖。圖4光電倍增結(jié)構(gòu)示意圖圖4光電倍增結(jié)構(gòu)示意圖從圖中可以看到光電倍增管也有一個陰極K和一個陽極A，與光電管不同的是在它的陰極和陽極間設(shè)置了若干個二次發(fā)射電極，D1、D2、D3…它們稱為第一倍增電極、第二倍增電極、…，倍增電極通常為10～15級。光電倍增管工作時，相鄰電極之間保持一定電位差，其中陰極電位最低，各倍增電極電位逐級升高，陽極電位最高。當(dāng)入射光照射陰極K時，從陰極逸出的光電子被第一倍增電極D1加速，以高速轟擊D1，引起二次電子發(fā)射，一個入射的光電子可以產(chǎn)生多個二次電子，D1發(fā)射出的二次電子又被D1、D2問的電場加速，射向D2并再次產(chǎn)生二次電子發(fā)射……，這樣逐級產(chǎn)生的二次電子發(fā)射，使電子數(shù)量迅速增加，這些電子最后到達(dá)陽極，形成較大的陽極電流。若倍增電極有n級，各級的倍增率為σ，則光電倍增管的倍增率可以認(rèn)為是σN，因此，光電倍增管有極高的靈敏度。在輸出電流小于1mA的情況下，它的光電特性在很寬的范圍內(nèi)具有良好的線性關(guān)系。光電倍增管的這個特點，使它多用于微光測量。3、光敏電阻光敏電阻的工作原理是基于內(nèi)光電效應(yīng)。在半導(dǎo)體光敏材料的兩端裝上電極引線，將其封在帶有透明窗的管殼里就構(gòu)成了光敏電阻。光敏電阻的特性和參數(shù)如下：1）暗電阻光敏電阻置于室溫、全暗條件下的穩(wěn)定電阻值稱為暗電阻，此時流過電阻的電流稱為暗電流。2)亮電阻光敏電阻置于室溫和一定光照條件下測得穩(wěn)定電阻值稱為亮電阻，此時流過電阻的電流稱為亮電流。4、伏安特性光敏電阻兩端所加的電壓和流過光敏電阻的電流間的關(guān)系稱為伏安特性，如圖5所示。從圖中可知，伏安特性近似直線，但使用時應(yīng)限制光敏電阻兩端的電壓，以免超過虛線所示的功耗區(qū)。圖5光敏電阻的伏安特性5、光電特性光敏電阻兩極間電壓固定不變時，光照度與亮電流間的關(guān)系稱為光電特性。光敏電阻的光電特性呈非線性，這是光敏電阻的主要缺點之一。6、光譜特性入射光波長不同時，光敏電阻的靈敏度也不同。入射光波長與光敏器件相對靈敏度間的關(guān)系稱為光譜特性。使用時可根據(jù)被測光的波長范圍，選擇不同材料的光敏電阻。7、響應(yīng)時間光敏電阻受光照后，光電流需要經(jīng)過一段時間（上升時間）才能達(dá)到其穩(wěn)定值。同樣，在停止光照后，光電流也需要經(jīng)過一段時間（下降時間）才能恢復(fù)到其暗電流值，這就是光敏電阻的時延特性。光敏電阻上升響應(yīng)時間和下降響應(yīng)時間約為10-1～10-3s，即頻率響應(yīng)為10Hz～1000Hz，可見光敏電阻不能用在要求快速響應(yīng)的場合，這是光敏電阻的一個主要缺點。8、溫度特性光敏電阻受溫度影響甚大，溫度上升，暗電流增大，靈敏度下降，這也是光敏電阻的另一缺點。9、頻率特性頻率特性是指外加電壓和入射光強一定是，光電流I與入射光的調(diào)制頻率f之間的關(guān)系，，光電二極管的頻率特性較光電三極管的頻率特性好，這是由于光電三極管的基射結(jié)存在電容和載流子基區(qū)需要時間的緣故。利用內(nèi)光電效率原理制造的光電元件的頻率特性最差，這是由于俘獲載流子和釋放電荷都需要一定時間的緣故。三、光電傳感器光電傳感器是通過把光強度的變化轉(zhuǎn)換成電信號的變化來實現(xiàn)控制的，它的基本結(jié)構(gòu)如圖6，它首先把被測量的變化轉(zhuǎn)換成光信號的變化,然后借助光電元件進(jìn)一步將光信號轉(zhuǎn)換成電信號.光電傳感器一般由光源,光學(xué)通路和光電元件三部分組成.光電檢測方法具有精度高,反應(yīng)快,非接觸等優(yōu)點,而且可測參數(shù)多,傳感器的結(jié)構(gòu)簡單,形式靈活多樣,因此,光電式傳感器在檢測和控制中應(yīng)用非常廣泛.光電傳感器一般由三部分構(gòu)成，它們分為：發(fā)送器、接收器和檢測電路，如圖7所示，發(fā)送器對準(zhǔn)目標(biāo)發(fā)射光束，發(fā)射的光束一般來源于半導(dǎo)體光源，發(fā)光二極管(LED)、激光二極管及紅外發(fā)射二極管。光束不間斷地發(fā)射，或者改變脈沖寬度。接收器有光電二極管、光電三極管、光電池組成。在接收器的前面，裝有光學(xué)元件如透鏡和光圈等。在其后面是檢測電路，它能濾出有效信號和應(yīng)用該信號。此外，光電開關(guān)的結(jié)構(gòu)元件中還有發(fā)射板和光導(dǎo)纖維，三角反射板是結(jié)構(gòu)牢固的發(fā)射裝置。它由很小的三角錐體反射材料組成，能夠使光束準(zhǔn)確地從反射板中返回，具有實用意義。它可以在與光軸0到25的范圍改變發(fā)射角，使光束幾乎是從一根發(fā)射線，經(jīng)過反射后，還是從這根反射線返回。圖7光電傳感器是一種依靠被測物與光電元件和光源之間的關(guān)系，來達(dá)到測量目的的，因此光電傳感器的光源扮演著很重要的角色，光電傳感器的電源要是一個恒光源，電源穩(wěn)定性的設(shè)計至關(guān)重要，電源的穩(wěn)定性直接影響到測量的準(zhǔn)確性，常用光源有以下幾種：1、發(fā)光二極管是一種把電能轉(zhuǎn)變成光能的半導(dǎo)體器件。它具有體積小、功耗低、壽命長、響應(yīng)快、機械強度高等優(yōu)點，并能和集成電路相匹配。因此，廣泛地用于計算機、儀器儀表和自動控制設(shè)備中。2、絲燈泡這是一種最常用的光源，它具有豐富的紅外線。如果選用的光電元件對紅外光敏感，構(gòu)成傳感器時可加濾色片將鎢絲燈泡的可見光濾除，而僅用它的紅外線做光源，這樣，可有效防止其他光線的干擾。3、激光激光與普通光線相比具有能量高度集中，方向性好，頻率單純、相干性好等優(yōu)點，是很理想的光源。由光源、光學(xué)通路和光電器件組成的光電傳感器在用于光電檢測時，還必須配備適當(dāng)?shù)臏y量電路。測量電路能夠把光電效應(yīng)造成的光電元件電性能的變化轉(zhuǎn)換成所需要的電壓或電流。不同的光電元件，所要求的測量電路也不相同。下面介紹幾種半導(dǎo)體光電元件常用的測量電路。半導(dǎo)體光敏電阻可以通過較大的電流，所以在一般情況下，無需配備放大器。在要求較大的輸出功率時，可用圖8所示的電路。圖9（a）給出帶有溫度補償?shù)墓饷舳O管橋式測量電路。當(dāng)入射光強度緩慢變化時，光敏二極管的反向電阻也是緩慢變化的，溫度的變化將造成電橋輸出電壓的漂移，必須進(jìn)行補償。圖中一個光敏二極管做為檢測元件，另一個裝在暗盒里，置于相鄰橋臂中，溫度的變化對兩只光敏二極管的影響相同，因此，可消除橋路輸出隨溫度的漂移。光敏三極管在低照度入射光下工作時，或者希望得到