photoelectric sensor

Overviewofthesensor

Thephotoelectricsensorisgenerallycomposedoftwoparts:aprocessingpathandaprocessingelement.Thebasicprincipleisbasedonthephotoelectriceffect,whichconvertsthemeasuredchangesintoopticalsignalchanges,andthenfurtherconvertsnon-electricalsignalsintoelectricalsignalswiththehelpofphotoelectricelements.Thephotoelectriceffectreferstoilluminatinganobjectwithlight,whichcanbeseenasaseriesofphotonswithacertainenergybombardingtheobject.Atthistime,theenergyofthephotonistransferredtotheelectron,andtheentireenergyofaphotonisallatonce.Whentheelectronisabsorbed,thestateoftheelectronwillchangeafteritreceivestheenergytransferredbythephoton,sothattheobjectirradiatedbythelightproducesacorrespondingelectriceffect.Thephotoelectriceffectisusuallydividedintothreecategories:(1)Thephenomenonthatcancauseelectronstooverflowthesurfaceoftheobjectundertheactionoflightiscalledtheexternalphotoelectriceffect,suchasphotoelectrictube,photomultipliertube,etc.;(2)ThephenomenonthatcanmaketheobjectundertheactionoflightThephenomenonthattheresistivitychangesiscalledtheinternalphotoelectriceffect,suchasphotoresistors,phototransistors,etc.;(3)Thephenomenonthatanobjectgeneratesacertaindirectionalelectromotiveforceundertheactionoflightiscalledthephotovoltaiceffect,suchasphotovoltaiccells.

Thephotoelectricdetectionmethodhastheadvantagesofhighaccuracy,fastresponse,non-contact,etc.,andhasmanymeasurableparameters.Thesensorhasasimplestructureandflexibleforms.Therefore,thephotoelectricsensoriswidelyusedindetectionandcontrol..

Photoelectricsensoristhekeyelementtorealizephotoelectricconversioninvariousphotoelectricdetectionsystems.Itisadevicethatconvertslightsignals(visibleandultravioletlaserlight)intoelectricalsignals.

Thephotoelectricsensorisasensorthatusesaphotoelectricdeviceasaconversionelement.Itcanbeusedtodetectnon-electricalphysicalquantitiesthatdirectlycausechangesinlightintensity,suchaslightintensity,illuminance,radiationtemperaturemeasurement,gascompositionanalysis,etc.;itcanalsobeusedtodetectothernon-electricalquantitiesthatcanbeconvertedintolightvolumechanges,suchaspartdiameter,surfaceroughness,Strain,displacement,vibration,speed,acceleration,aswellastherecognitionoftheshapeandworkingstateoftheobject,etc.Photoelectricsensorshavethecharacteristicsofnon-contact,fastresponse,reliableperformance,etc.,sotheyarewidelyusedinindustrialautomationdevicesandrobots.Theemergenceofnewphotoelectricdevices,especiallythebirthofCCDimagesensors,hasopenedanewpageforthefurtherapplicationofphotoelectricsensors.

Principle

Theopticalmeasurementandcontrolsystemmadebythedifferentprincipleoftheluminousfluxonthephotoelectricelementisdiverse,andcanbedividedaccordingtothenatureoftheoutputofthephotoelectricelement(opticalmeasurementandcontrolsystem)Thesecondcategoryisanalogphotoelectricsensorandpulse(switch)photoelectricsensor.Theanalogphotoelectricsensorconvertsthemeasuredintoacontinuouslychangingphotocurrent,whichhasasinglevaluerelationshipwiththemeasured.Theanalogphotoelectricsensorcanbedividedintotransmission(absorption)typeanddiffusereflectionaccordingtothemethodofbeingmeasured(detectingtargetobjects)Threetypes:shadingtype(beamblocking).Theso-calledtransmissivetypemeansthatthemeasuredobjectisplacedinthelightpath,andthelightenergyemittedbytheconstantlightsourcepassesthroughthemeasuredobject,andafterpartofitisabsorbed,thetransmittedlightisprojectedontothephotoelectricelement;theso-calleddiffusereflectiontypereferstothelightemittedbytheconstantlightsourceProjectedontheobjecttobemeasured,andthenreflectedfromthesurfaceoftheobjecttobemeasuredandthenprojectedontothephotoelectricelement;theso-calledshadingtypereferstothelightfluxthatisprojectedontothephotoelectricelementwhenthelightfluxemittedbythelightsourceisshieldedbythelightofthemeasuredobjectChange,thedegreeofchangeisrelatedtothepositionofthemeasuredobjectinthelightpath.

Photodiodesarethemostcommonlightsensors.Theappearanceofthephotodiodeisthesameasthatofanormaldiode.Whenthereisnolight,itisthesameasanormaldiode.Thereversecurrentisverysmall,whichiscalledthedarkcurrentofthephotodiode.Whenthereislight,thecarriersareexcitedtoproduceelectron-empty.Holesarecalledphotoelectriccarriers.Undertheactionofanexternalelectricfield,photoelectriccarriersparticipateinconductionandformareversecurrentmuchlargerthanthedarkcurrent.Thisreversecurrentiscalledphotocurrent.Thesizeofthephotocurrentisproportionaltothelightintensity,soanelectricalsignalthatchangeswiththelightintensitycanbeobtainedontheloadresistance.

Inadditiontothephotodiode'sfunctionofconvertinglightsignalsintoelectricalsignals,thephototransistoralsohasthefunctionofamplifyingelectricalsignals.Theshapeofthephotosensitivetriodeisnotmuchdifferentfromthatofthegeneraltriode.Generally,thephotosensitivetriodeonlyleadsouttwoelectrodes-emitterandcollector.Thebaseisnotleadout,andtheshellalsohasawindowtoallowlighttoenter.Inordertoincreasetheillumination,theareaof​​thebaseareaismadelarge,theemissionareaissmall,andtheincidentlightismainlyabsorbedbythebasearea.Whenworking,thecollectorjunctionisreversebiased,andthelaunchjunctionisforwardbiased.Whenthereisnolight,thecurrentflowingthroughthetubeisthedarkcurrentIceo=(1+β)Icbo(verysmall),whichissmallerthanthepenetrationcurrentofageneraltriode;whenthereislight,alargenumberofelectron-holepairsareexcited,makingThecurrentIbgeneratedbythebaseincreases,andthecurrentflowingthroughthetubeatthismomentiscalledthephotocurrent,theemittercurrentIe=(1+β)Ib,itcanbeseenthatthephototransistorhashighersensitivitythanthephotodiode.

Workingprinciple

Thephotoelectricsensoriscontrolledbyconvertingthechangeoflightintensityintothechangeofelectricalsignal.

Undernormalcircumstances,thephotoelectricsensorconsistsofthreeparts,whicharedividedinto:transmitter,receiveranddetectioncircuit.

Thetransmitterisaimedatthetargettoemitalightbeam,andtheemittedlightbeamgenerallycomesfromasemiconductorlightsource,lightemittingdiode(LED),laserdiodeandinfraredemittingdiode.Thebeamisemitteduninterrupted,orthepulsewidthischanged.Thereceiveriscomposedofaphotodiode,aphototransistor,andaphotocell.Infrontofthereceiver,opticalcomponentssuchaslensandapertureareinstalled.Behinditisthedetectioncircuit,whichcanfilterouttheeffectivesignalandapplythesignal.

Inaddition,thereareemissionplatesandopticalfibersinthestructuralelementsofthephotoelectricswitch.

Classificationandworkingmethod

⑴Slotphotoelectricsensor

Placealightemitterandareceiverfacetofaceonbothsidesofaslottoformaslot形光光。Shapephotoelectric.Theilluminatorcanemitinfraredlightorvisiblelight,andthelightreceivercanreceivelightwithoutobstruction.Butwhenthedetectedobjectpassesthroughtheslot,thelightisblocked,thephotoelectricswitchwillact,andoutputaswitchcontrolsignaltocutofforturnontheloadcurrent,therebycompletingacontrolaction.Thedetectiondistanceoftheslotswitchisgenerallyonlyafewcentimetersduetothelimitationoftheoverallstructure.

⑵Thethrough-beamphotoelectricsensor,ifthelightemitterandthelightreceiverareseparated,thedetectiondistancecanbeincreased.Alightemitterandalightreceiverformathrough-beamseparatedphotoelectricswitch,referredtoasOn-beamphotoelectricswitch.Thedetectiondistanceofthethrough-beamphotoelectricswitchcanreachseveralmetersoreventensofmeters.Whenthethrough-beamphotoelectricswitchisused,thelightemitterandthelightreceiverarerespectivelyinstalledonbothsidesofthepassingpathofthedetectionobject,andthelightpathisblockedwhenthedetectionobjectpasses,andthelightreceiveractstooutputaswitchcontrolsignal.

⑶Reflectiveplatetypephotoelectricswitch

Placethelightemitterandthelightreceiverinthesamedevice,installareflectorinthefront,andusetheprincipleofreflectiontocompletethephotoelectriccontrolfunction.Itisareflectorreflectiontype(ormirrorreflectiontype)photoelectricswitch.Undernormalcircumstances,thelightsourceemittedbytheilluminatorisreflectedbythereflectorandthenreceivedbythereceiver;oncethedetectedobjectblocksthelightpathandthereceivercannotreceivelight,thephotoelectricswitchwillactandoutputaswitchcontrolsignal.

⑷Diffuse-reflectivephotoelectricswitch

Thedetectionheadofthediffuse-reflectivephotoelectricswitchisalsoequippedwithalightemitterandalightreceiver,butthereisnoreflectioninthefrontofthediffuse-reflectivephotoelectricswitchplate.Undernormalcircumstances,thelightreceiverfromtheilluminatorcannotbefound.Duringdetection,whenthedetectedobjectpassesthroughandblocksthelight,andpartiallyreflectsthelightback,thereceiverreceivesthelightsignalandoutputsaswitchsignal.

Thereasonwhythereisnosignaloutput

Thefirstthingtoconsideristhewiringorconfiguration.Forthethrough-beamtypephotoelectricsensor,itmustbeusedincombinationwiththelight-emittingpartandthelight-receivingpart,andpowerisrequiredatbothends;whiletheretro-reflectivetypemustbeusedincombinationwiththesensorprobeandtheretro-reflectiveplate;atthesametime,theusermustprovideastablepowersupplyforthesensor,ifitisForDCpowersupply,thepositiveandnegativepolesmustbeconfirmed.Ifthepositiveandnegativepolesareconnectedincorrectly,theoutputsignalwillbemissing.

Theabovereasonanalysisistheconsiderationofthephotoelectricsensoritself.Whatwealsoneedtoconsideristhepositionofthedetectedobject.Ifthedetectedobjectisnotinthedetectionarea,suchdetectionisfutile.Thedetectionobjectmustbewithintheareathatthesensorcandetect,thatis,withintherangethatthephotoelectriccandetect.Secondly,itisnecessarytoconsiderwhethertheopticalaxisofthesensorisaligned.Theopticalaxisofthethrough-beamtypeprojectingpartandthelightreceivingpartmustbealigned,andthecorrespondingretro-reflectiveprobepartandtheopticalaxisofthereflectormustbealigned.Thesamethingtoconsideriswhetherthedetectionobjectmeetsthestandarddetectionobjectortheminimumdetectionobjectstandard.Thedetectionobjectcannotbesmallerthantheminimumdetectionobjectstandard,soastoavoidcausingthethrough-beamtypeandthereflectiontypetonotbeabletodetecttransparentobjectswell,likethereflectiontype.Thecolorofthedetectedobjectisrequired.Thedarkerthecolor,thecloserthedetectiondistance.

Iftheaboveconditionscanbeclearlyeliminated,whatweneedtodoistodetecttheinterferencefactorsoftheenvironment.Forexample,thelightintensitycannotexceedtheratedrange;ifthereisdustinthesiteenvironment,weneedtocleanthesurfaceofthephotoelectricsensorproberegularly;ormultiplesensorsareinstalledcloselyandinterferewitheachother;thereisalsoelectricalinterferencethathasagreaterimpact.High-powerequipmentmusthavecorrespondinganti-interferencemeasureswheninterferenceoccurs.Ifyouhavedonetheabove-mentionedinvestigationsonebyone,andthesefactorscanbeclearlyeliminatedorthereisnosignaloutput,itisrecommendedtoreturntothemanufacturerforinspectionandjudgment.

Structuralanalysis

Photoelectricsensorsusuallyconsistofthreeparts:transmitter,receiveranddetectioncircuit.

Thetransmitterisequippedwithacalibrationlenstofocusthelighttowardsthereceiver,andthereceivercableconnectsthedevicetoavacuumtubeamplifier.Thereisasmallincandescentlampasthelightsourceinthemetalcylinder.Thesesmallandsturdyincandescentlampsensorsaretheembryonicformoftoday'sphotoelectricsensors.

Thereceiveriscomposedofphotodiodes,phototransistorsandphotocells.Photodiodesarenowthemostcommonsensors.Theappearanceofthephotodiodeofthephotoelectricsensoristhesameasthatofageneraldiode,exceptthatthereisawindowembeddedinglassontheshellofthephotoelectricsensor,sothatlightcanenter.Inordertoincreasethelightreceivingarea,theareaof​​thePNjunctionismadelarger,andthephotodiodeworksInthereverse-biasedworkingstate,andinserieswiththeloadresistance,whenthereisnolight,itisthesameasanordinarydiode,thereversecurrentisverysmall,calledthedarkcurrentofthephotodiode;whenthereislight,thecarriersareExcitedtogenerateelectron-holes,calledphotoelectriccarriers.

Inaddition,thereareemissionplatesandopticalfibersinthestructuralelementsofthephotoelectricsensor.Thecornerreflectorisastronglaunchingdevice,whichiscomposedofasmalltriangularpyramidreflectingmaterial,whichcanmakethelightbeamaccuratelyreturnfromthereflector.Itcanchangetheemissionanglefrom0to25relativetotheopticalaxis,sothatthelightbeamisalmostfromanemissionline,andafterreflection,itstillreturnsfromthisreflectionline.

Type

⑴Slot-typephotoelectricsensor

Alightemitterandareceiveraremountedface-to-faceonbothsidesofaslotisaslot-shapedphotoelectricsensor.Theilluminatorcanemitinfraredlightorvisiblelight,andthelightreceivercanreceivelightwithoutobstruction.Butwhenthedetectedobjectpassesthroughtheslot,thelightisblocked,andthephotoelectricswitchisactivated.Outputaswitchcontrolsignaltocutofforswitchontheloadcurrenttocompleteacontrolaction.Thedetectiondistanceoftheslotswitchisgenerallyonlyafewcentimetersduetothelimitationoftheoverallstructure.

⑵Through-beamphotoelectricsensor

Ifthelight-emittingdeviceandthelight-receivingdeviceareseparated,thedetectiondistancecanbeincreased.Thephotoelectricswitchcomposedofalightemitterandalightreceiveriscalledathrough-beamseparatephotoelectricswitch,orathrough-beamphotoelectricswitchforshort.Itsdetectiondistancecanreachseveralmetersoreventensofmeters.Wheninuse,thelightemitterandthelightreceiverarerespectivelyinstalledonbothsidesofthepassingpathofthedetectedobject,andthelightpathisblockedwhenthedetectedobjectpasses,andthelightreceiveractstooutputaswitchcontrolsignal.

⑶Reflectiveplatetypephotoelectricswitch

Putthelightemitterandthelightreceiverintothesamedevice,installareflectorinfrontofit,andusethereflectionprincipletocompletethephotoelectriccontrolfunctionItiscalledthereflectorreflectiontype(ormirrorreflectiontype)photoelectricswitch.Undernormalcircumstances,thelightemittedbythelightemitterisreflectedbythereflectorandreceivedbythelightreceiver;oncethelightpathisblockedbythedetectionobjectandthelightreceivercannotreceivelight,thephotoelectricswitchwillactandoutputaswitchcontrolsignal.

⑷Diffusereflectiontypephotoelectricswitch

Italsohasalightemitterandalightreceiverinthedetectionhead,butthereisnoreflectorinthefront.Undernormalcircumstances,thelightreceiverfromtheilluminatorcannotbefound.Whenthedetectionobjectpassesthroughandblocksthelightandreflectspartofthelightback,thereceiverreceivesthesignalandoutputsaswitchsignal.

Classification

Standardtype

1)Diffusereflectiontype:generaltypeorenergytype(-8),focustype(-8-H),withBackgroundsuppressionfunctiontype(-8-H),backgroundanalysisfunctiontype(-8-HW)

2)Reflectortype:generaltype(-6),polarizationfilterfunctiontype(-54,-55),withtransparentbodydetectionfunction(-54-G),withforegroundsuppressionfunction(-54-V)

3)through-beamtype

4)Slottype

5)Fiberopticsensor:plasticfibertype,glassfibertype

6)Colormarksensor,colorsensor,fluorescencesensor

7)Opticalcommunication

8)Laserranging:triangularreflectionprincipletype,phasedifferenceprincipletype,timedifferenceprincipletype

9)grating

10)explosion-proof/flameprooftype

Safetytype

1)Safetythrough-beamphotoelectric

2)Safetygrating

3)Safetylightcurtain

4)Safetycontroller

Gatecontroltype

1)Radarsensor:areadetectiontype

2)Activesensor:singlebeamtype,multipleBeamtype,areadetectiontype

3)Passivesensor:areadetectiontype

4)Elevatorlightcurtain

5)Generaloptoelectronics:troughshape,throughbeamType,etc.

Features

①Longdetectiondistance

Ifthedetectiondistanceofmorethan10misreservedinthethrough-beamtype,otherdetectionmethods(magnetic,Ultrasonic,etc.)Cannotdetectremotely.

②Therearefewrestrictionsondetectingobjects

Becausethedetectionprincipleisbasedontheshadingandreflectioncausedbythedetectingobject,itisnotlikeaproximitysensorthatlimitsthedetectingobjecttometal.Almostallobjectssuchasglass,plastic,wood,liquid,etc.aretested.

③Shortresponsetime

Thelightitselfishigh-speed,andthesensorcircuitiscomposedofelectronicparts,soitdoesnotincludemechanicalworkingtime,andtheresponsetimeisveryshort.

④Highresolution

Highresolutioncanbeachievedbyusingadvanceddesigntechnologytoconcentratetheprojectingbeamonasmallspot,orbyformingaspeciallight-receivingopticalsystem.Itcanalsodetectsmallobjectsandhigh-precisionpositiondetection.

⑤Canrealizenon-contactdetection

Itcanrealizedetectionwithoutmechanicallytouchingthedetectionobject,soitwillnotcausedamagetothedetectionobjectandsensor.Therefore,thesensorcanbeusedforalongtime.

⑥Canrealizecolordiscrimination

Thereflectanceandabsorptivityofthelightformedbythedetectionobjectvaryaccordingtothewavelengthofthelightprojectedandthecolorcombinationofthedetectionobject.Usingthisproperty,thecolorofthedetectedobjectcanbedetected.

⑦Easytoadjust

Inthetypeofprojectedvisiblelight,theprojectedbeamisvisibletotheeyes,whichisconvenientforadjustingthepositionofthedetectedobject.

Application

Photoelectricsensorsthatusephotoelectricelementsassensitiveelementshaveawidevarietyofapplicationsandarewidelyused.Accordingtothenatureoftheoutputofthephotoelectricsensor,itcanbedividedintotwocategories:(1)Thephotoelectricmeasuringinstrumentmadebyconvertingthemeasurementintoacontinuouslychangingphotocurrentcanbeusedtomeasuretheintensityoflightandthetemperature,transmittance,anddisplacementoftheobject.Physicalquantitiessuchassurfaceconditions.Forexample:illuminancemeterformeasuringlightintensity,photoelectricpyrometer,photoelectriccolorimeterandturbiditymeter,photoelectricalarmtopreventfire,constituteautomaticdetectiondeviceforcheckingthediameter,length,ovalityandsurfaceroughnessofprocessedpartsandTheinstrumentanditssensitivecomponentsareallphotoelectriccomponents.Semiconductoroptoelectroniccomponentsarenotonlywidelyusedinthecivilianindustry,butalsohaveanimportantpositioninthemilitary.Forexample,leadsulfidephotoresistorscanbemadeintoinfrarednightvisiondevices,infraredcamerasandinfrarednavigationsystems,etc.;(2)Convertthemeasuredintoacontinuouslychangingphotocurrent.Variousphotoelectricautomaticdevicesaremadewiththecharacteristicsof"with"or"without"electricalsignaloutputwhenphotoelectricelementsareirradiatedbylightornolight.Thephotoelectricelementisusedasaswitch-typephotoelectricconversionelement.Forexample,thephotoelectricinputdeviceoftheelectroniccomputer,theswitchtypetemperatureadjustingdeviceandthedigitalphotoelectricspeedmeasuringinstrumentoftherotationalspeedmeasurement,etc.

1.Smokeanddustturbiditymonitor

Preventingindustrialsmokeanddustpollutionisoneoftheimportanttasksofenvironmentalprotection.Inordertoeliminateindustrialsmokeanddustpollution,wemustfirstknowtheamountofsmokeanddustemissions.Therefore,thesourceofthesmokeanddustmustbemonitored,automaticallydisplayedandalarmedforexceedingthestandard.Theturbidityofthesmokeanddustintheflueisdetectedbythesizeofthechangeduringthetransmissionoflightintheflue.Iftheflueturbidityincreases,thelightemittedbythelightsourceisabsorbedandrefractedbythesootparticles,andthelightreachingthephotodetectordecreases.Therefore,thestrengthoftheoutputsignalofthephotodetectorcanreflectthechangeofflueturbidity.

2.Barcodescanningpen

Whenthescanningpenheadmovesonthebarcode,ifitencountersablackline,thelightoftheLEDwillbeabsorbedbytheblackline,Thephotosensitivetriodecannotreceivethereflectedlight,presentsahighimpedance,andisinacut-offstate.Whenencounteringthewhiteinterval,thelightemittedbythelight-emittingdiodeisreflectedtothebaseofthephotosensitivetriode,andthephotosensitivetriodegeneratesaphotocurrenttoconduct.Aftertheentirebarcodehasbeenscanned,thephototransistordeformsthebarcodeintoindividualelectricalpulsesignals,whichareamplifiedandreshapedtoformapulsetrain,whichisthenprocessedbythecomputertocompletetheidentificationofthebarcodeinformation.3.Productcounter

Whentheproductisrunningontheconveyorbelt,itcontinuouslyshieldsthelightpathfromthelightsourcetothephotoelectricsensor,sothatthephotoelectricpulsecircuitgeneratesanelectricpulsesignal.Everytimetheproductisshaded,thephotoelectricsensorcircuitgeneratesapulsesignal.Therefore,thenumberofoutputpulsesrepresentsthenumberofproducts.Thepulseiscountedbythecountingcircuitanddisplayedbythedisplaycircuit.

Four.Photoelectricsmokealarm

Whenthereisnosmoke,thelightemittedbythelight-emittingdiodetravelsstraight,andthephototransistordoesnotreceivethesignal.Whenthereisnooutput,whenthereissmoke,thelightemittedbythelight-emittingdiodeisrefractedbythesmokeparticles,sothatthetriodereceivesthelight,hasasignaloutput,andsendsanalarm.

Five.Measuringthespeed

Coattherotatingshaftofthemotorwithblackandwhitecolors.Whenrotating,reflectedlightandnon-reflectedlightalternatelyappear.Thephotoelectricsensorcorrespondinglyintermittentlyreceivesthereflectedsignalofthelight,andoutputstheintermittentelectricalsignal,andthenisamplifiedandshapedbytheamplifierandtheshapingcircuittooutputthesquarewavesignal,andfinallytheelectronicdigitaldisplayoutputsthemotorspeed.

6Theapplicationofphotocellsinphotoelectricdetectionandautomaticcontrol

Whenphotocellsareusedasphotoelectricdetection,itsbasicprinciplesSameasphotodiodes,buttheirbasicstructureandmanufacturingprocessarenotexactlythesame.Sincethephotovoltaiccelldoesnotrequireanexternalvoltagewhenworking;ithashighphotoelectricconversionefficiency,widespectralrange,goodfrequencycharacteristics,lownoise,etc.,ithasbeenwidelyusedinphotoelectricreadout,photoelectriccoupling,gratingranging,lasercollimation,filmsoundrecovery,etc.,UVmonitorsandflameoutprotectiondevicesforgasturbines,etc.

Applicationcase

Theapplicationofphotoelectricsensortolaserweapons

Becausephotoelectricsensorissensitivetoinfraredradiation,orvisiblelight,orbothTheyareextremelysensitive,sotheyaremorelikelytobetargetsoflaserattacks.Inaddition,theelectronicsystemandthesensoritselfareextremelysusceptibletotheinterferenceofthermalnoiseandelectromagneticnoisegeneratedbythelaserandcannotworknormally.Thelaserweaponsonthebattlefieldattackthephotoelectricsensormainlyinthefollowingways:Usealaserbeamofappropriateenergyto"blind"thesensorsothatitcannotdetectorcontinuetotrackthetargetthathasbeendetected.Or,ifthesensorisguidingtheweapontothetarget,blindingwillmakeitlosethetarget.Insummary,becausesensorsplayanincreasinglyimportantroleonthebattlefield,andatthesametimearevulnerabletolaserattacks,theyhavebecomethepreferredtargetoflow-energylaserweapons.

Photoelectricsensorsareusedinautomaticmeterreadingsystems

Withthedevelopmentofmicroelectronicstechnology,sensortechnology,computertechnologyandmoderncommunicationtechnology,photoelectricsensorscanbeusedSensorstodevelopautomaticmeterreadingsystem.Thealuminumplateoftheelectricenergymeterisdriventorotatebythetorquegeneratedundertheactionoftheelectriceddycurrentandthemagneticfield.Thephotoelectricsensorcanconvertthenumberofrevolutionsofthealuminumplateintothenumberofpulses.Forexample,iftherotatingbrightaluminumplateispartiallyblacked,andequippedwithareflectivephotoelectrictransmittingandreceivingpairtube,whenthealuminumplaterotates,pulsesaregeneratedinthepartiallyblackedarea,andthenumberofrevolutionsofthealuminumplatecanbesampledItisconvertedintothecorrespondingpulsenumber,andsenttotheT0portoftheCPUforcountingprocessingthroughthephotoelectriccouplingisolationcircuit.Theuseofphotoelectriccouplingisolatorcaneffectivelypreventinterferencesignalsfromenteringthemicrocomputer.Combinedwithothertransmissionmethods,anautomaticmeterreadingsystemcanbeformed.

Thephotoelectricsensorisusedtomonitorsmokepollution

Thephotoelectricsensorisasmallelectronicdevice,whichcandetectitsreceivingThechangeofthereceivedlightintensityrealizesthecontrolfunctionbyconvertingthechangeofthelightintensityintothechangeoftheelectricalsignal.Becausephotoelectricsensorshavethecharacteristicsofnon-contact,fastresponse,reliableperformance,etc.,theyarewidelyusedinindustrialautomationdevicesandrobots.Wecanusethecharacteristicsofphotoelectricsensorstodetectsmokeanddust,sotheoutputsignalofphotoelectricsensorsisstrongorweak.Itcanreflectthechangeofflueturbidity.

Sanitaryanti-flushingphotoelectricsensor

Theanti-flushingsensorcanprovideextremelyhighreliabilityandcomfort,andreduceoperatingcostslowest.WiththeIO-LinkinterfaceandtheproTect+sealingconceptthatcangreatlyextendtheservicelife,thesetwonewsensorsaresuitableforharshapplicationenvironmentsandcanberegardedasidealsolutionsforthefoodandbeverageindustry.

Characteristics

1)Widetransientresponserange,strongharmonicmeasurementcapability

TheprosandconsoftransientcharacteristicsaretojudgewhetheratransformercanbeAnimportantparametertobeappliedinthepowersystem,especiallythecoordinationwiththeactiontimeoftherelayprotection.Traditionalelectromagnetictransformershavepoorresponsecharacteristicstohigh-frequencysignalsduetotheexistenceofironcores,andcannotaccuratelyreflectthetransientprocessontheprimaryside.Thefrequencyrangeofthephotoelectrictransformerismainlydeterminedbytheelectroniccircuitpart,andthereisnoproblemofironcoresaturation,soitcanaccuratelyreflectthetransientprocessoftheprimaryside.Generally,itcanbedesignedto0.1Hzto1MHz,andspecialcanbedesignedto200MHzbandpass.Thestructureofthephotoelectricsensorcanmeasureharmonicsonhigh-voltagepowerlines.Theelectromagneticinductiontransformerisdifficulttoachieve.

2)Digitalinterface,strongcommunicationability

Becausethephotoelectricsensordownloadstheopticaldigitalsignal,itiseasytointerfacewiththecommunicationnetwork,andthereisnomeasurementerrorinthetransmissionprocess.Atthesametime,withthewidespreadadoptionofmicrocomputerizedprotectionandcontrolequipment,thephotoelectrictransformercandirectlyprovidedigitalquantitiestothesecondaryequipment,sothattheconverterandA/Dsamplingpartintheoriginalprotectiondevicecanbeomitted,sothatthesecondaryequipmentcanobtainGreatsimplification,topromotetheresearchofnewprinciplesofprotection.

3)Smallsize,lightweight,andeasytoupgrade,meetingtherequirementsofminiaturizationandcompactnessofsubstations.Sincephotoelectricsensorsrelyonsensorheadsandelectroniccircuitsforsignalacquisitionandprocessing,theyaresmallinsizeandweight.Generallybelow1000kg,itiseasytointegrateinAISorGIS,whichwillgreatlyreducetheareaof​​thesubstationandmeettherequirementsofminiaturizationandcompactnessofthesubstation.Atthesametime,thephotoelectrictransformerisconnectedwiththesecondaryequipmentthroughasmallnumberofopticalcables,whichcangreatlyreducethecabletrenchandcable.

Marketfield

Themainapplicationfieldofphotoelectricsensor:carentertainment/navigation/DVDsystembacklightcontrol,sothattheidealbacklightbrightnesscanbedisplayedunderallambientlightconditions;Displaybacklightcontrolforrearseatentertainment;instrumentclusterbacklightcontrol(speedometer/tachometer);automaticrearviewmirrorbrightnesscontrol(usuallytwosensorsarerequired,oneisforwardandtheotherisbackward);automaticheadlightsAndrainwatersensorcontrol(dedicated,changedaccordingtodemand);rear-viewcameracontrol(dedicated,changedaccordingtodemand).Ithasbecomeoneofthemosteffectivesolutionsinprovidingmorecomfortabledisplayquality.Ithassimilarcharacteristicstothehumaneye,whichisessentialforautomotiveapplications,becausetheseapplicationsrequirethatitcanbeachievedunderallambientlightconditionsFullbacklighteffect.Forexample,inthedaytime,theuserneedsthemaximumbrightnesstoachievethebestvisibility,butthisbrightnessistoobrightfornightconditions,soalightsensorwithgoodspectralresponse(goodIRattenuation),appropriateThedynamicrangeandoverallgoodoutputsignaladjustmentcaneasilyautomatetheseapplications.Theendusercansetseveralthresholdlevels(suchaslow,medium,bright),orcandynamicallychangethesensor'sbacklightbrightnessatwill.Thisalsoappliestothebrightnesscontrolofcarrearviewmirrors.Intelligentbrightnessmanagementisrequiredwhenthemirrorbecomesdarkerand/orbrighter,whichcanbedonebytheambientlightsensor.

Forportableapplications,iftheuserdoesnotchangethesystemsettings(usuallybrightnesscontrol),thenadisplaywillalwaysconsumethesameamountofenergy.Inparticularlybrightareassuchasoutdoors,userstendtoincreasethebrightnessofthedisplay,whichwillincreasethepowerconsumptionofthesystem.Whentheconditionschange,suchasenteringabuilding,mostuserswillnotchangethesettings,sothesystempowerconsumptionremainshigh.However,byusingalightsensor,thesystemcanautomaticallydetectchangesinconditionsandadjustsettingstoensurethatthedisplayisatthebestbrightness,therebyreducingoverallpowerconsumption.Ingeneralconsumerapplications,thiscanalsoextendbatterylife.Formobilephones,pencomputers,PADsanddigitalcameras,theambientlightsensorfeedbackcanbeusedtoautomaticallycontrolbrightness,therebyextendingbatterylife.

Notanewidea.Thisideahasbeenrealizedbyphotodiodesandphotoresistorsdecadesago.Theso-callednewconceptmeansthatitcanreduceuselessinfraredandultravioletlightwhilebeingsensitivetoambientlight,anditcanalsoachieveasmallpackagewhilesupportingthestrictrequirementsoftheautomotivespecificationAECQ-1000,especiallytoensurethatthetemperatureis-40degreesto+Operationinthetemperaturerangeof105degrees(level2)tomeettherestofthespecifications.HowtomaintainworkqualitystandardsandmeettheAECQ-1000level2workrequirementsisachallengefacedinallopticaldesignsolutionstoday.WhenusingalightsensororLEDtransmitterorreceiver,anyopticalsolutionwillfacetheproblemofpackagediscoloration(itwilldarkenorturnyellow)whenexposedtoaconstanthightemperature(>+85degrees).Itisalsoworthmentioningthat,sofar,alltheapplicationsofambientlightsensorsarelimitedtothecabin,andthereisnolightsensorapplicationintheengineroomoroutdoorenvironment.Infact,evenifsuchapplicationsappear,opticalpackagesarenotdesignedforsuchharshconditions(+125or+150degreeconditions).Therefore,underthecurrentopticalpackagingtechnology,theymaynotbeabletowithstandsuchharshconditions.conditionsof.

Thelatestadvancesinthedevelopmentofsemiconductor-likesensorsandpackaginghaveenabledenduserstohaveawiderchoiceoflightsensors.Smallpackage,lowpowerconsumption,highintegrationandeaseofusearethereasonswhydesignersaremoreadoptingopticalsensors,andtheirapplicationsinvolveconsumerelectronics,industrialapplicationsandtheautomotivefield.

Newtechnologiesandapplications

1.256photocellarrayfour-quadrantCMOSphotoelectricsensorfortargettrackingandcoordinatepositioning

CombiningthetraditionalquadrantsensorwiththecurrentCombiningtherapidlydevelopingCMOSimagesensor,a256-unitphotoelectrictubearrayfour-quadrantCMOSphotoelectricsensorusingactivesensorarraylightisproposed.

Thephotosensitiveunitofthesensoradoptstheactivepixelsensor(ActivePixelSensor,APS)designusedintheCMOSimagesensor.Thephotoelectricsignalpreprocessingcircuitdirectlygeneratesthesensorinthephotosensitiveunit.Thephotoelectricsignalisconvertedintoalargerelectricalsignaloutput,whichavoidstheprocessingofweaksignalsandreducestheinfluenceofnoise.Thesensorusesthearraytocollecttheopticalsignal,whichcandirectlydeterminethecoordinatepositionofthetargetlightsourceandrealizequickadjustmentinonestep.ThesensorismanufacturedusingastandardCMOSprocess,andthesensorarrayandthesignalprocessingcircuitareintegratedonthesamechip,whichcanrealizetheSOCintegrationandintelligent(SmartSensor)designofthesensor.Itiswidelyusedinlasersighting,guidance,tracking,searchdevices,precisionmeasurement,suchaslasermicro-positioning,displacementmonitoring,andphotoelectriccontrolofprecisionmachinetools.Itisanewtypeofintegratedarrayfour-quadrantCMOSphotoelectricsensorfortargettrackingandcoordinatepositioning.

2.CMOSdigital-analoghybridsensorintegratedcircuitcompatiblewithphotosensitivequadrantarrayandmagneto-sensitivelinearray

Quadrantsensorsbasedonsiliconphotoelectricsensorsarewidelyusedinlasertrackingguidanceanddisplacementmonitoring,Precisionmachinetoolsandothercontrolfields.Silicon-basedsemiconductormagneticsensorsarewidelyusedinvariousmagneticfieldmetersformeasuringmagneticfieldstrength,variousmagneticheadsforreadinginformationonmagneticmedia,anddetectorsfornon-magneticsignals.

3.WeaksignaldetectionofSPRbiosensorsusingphotodiodearrays

Toimprovethedetectioncapabilitiesofsurfaceplasmonresonancebiomedicalsensors,usehigh-performancephotodiodearraysforphotoelectricconversionThedevicedemonstratesandimplementsadetectionmethodthatcaneffectivelysuppressnoise.Usingthecharacteristicsofphotodiodearraydevicesthatcanoutputreferencenoisesignals,throughcoherentdenoisingcombinedwithwaveletsoftthresholddenoising,theoutputsignal-to-noiseratiooftheSPRsensorisincreasedfromabout40dBTomorethan52dB.ExperimentsusingSPRsensorstodetectthespecificbindingofhumanimmunoglobulin(IgG)moleculesshowthatthismethodsignificantlyimprovestheresolutionoftheSPRsensor,sothatitcanaccuratelydetecttheIgGcontentinthesamplesolutionfrom10to(-3)mg/mL.Withaslightchangeintheorderofmagnitude,theaccuracyandresolutionareimprovedbymorethananorderofmagnitude.

4.Applicationofphotoelectricdetectionsensorarrayinmovingobjectdetection

AphotoelectricdetectionsensorarraybasedoncoveragetheoryandKalmanfilteralgorithm,thearrayhascollectionandprocessingarraycoverageThefunctionoftheinformationoftheperceivedobjectintheareaistodetectanddescribetheexistence,movementandtrajectoryoftheperceivedobject.

Researchstatusofphotoelectricsensorsathomeandabroad

Becausetheapplicationofphotoelectricsensorsinvolvesawiderangeoffields,itsresearchanddevelopmenthaveattractedgreatattentionintheworld,Countriesareracingtoresearchanddevelopandcausefiercecompetition.Ithasgraduallydevelopedfromitsinitialmilitaryapplicationtocivilaffairs,andiscloselyrelatedtoourlives.Itshouldbesaidthatmodernlifecannotbeseparatedfromtheparticipationofphotoelectricsensors,suchasfaxmachines,copiers,scanners,printers,garagedooropeners,liquidcrystaldisplays,colorThelistisendless,includingmeter,spectrometer,automobileandmedicaldiagnosticequipment.

TheUnitedStatesisoneoftheearliestandhighest-levelcountriesinthestudyofphotoelectricsensors,anditsapplicationsinthemilitaryandcivilianfieldsaredevelopingveryrapidly.Intermsofmilitaryapplications,researchanddevelopmentmainlyinclude:underwaterdetection,aviationmonitoring,nuclearradiationdetection,etc.TheUnitedStatesisalsothefirstcountrytousephotoelectricsensorsinthecivilianfield.Suchastheuseofphotoelectricsensorstomonitorimportantparameterssuchascurrentandtemperatureofthepowersystem,andtodetectbacteriaandvirusesinmeatandfood.TheUnitedStateshastheworld'smostcomprehensivephotoelectricsensorproductline,withmorethan12,000productsincludingself-containedorseparatedamplifiers,limitswitchappearanceorsmallsensors,precisiondetectionorlong-distancedetectionsensors,anddetectiondistancesupto305m.Andhasthemostcompletestandardopticalfiberandcustomizedopticalfiberproductsintheindustry.TheprotectionlevelofmostproductsreachesNEMA6PandIP67.JapanandWesternEuropeancountriesalsoattachgreatimportancetoandinvestalotofmoneyintheresearchanddevelopmentofphotoelectricsensors.Inthe1990s,avarietyoffirst-classcivilianphotoelectricsensorswereresearchedanddeveloped.Japaneseelectricalappliancesarewell-knownworldwidefortheirmoderatepricesandgoodquality.LargeenterprisesfromWesternEuropeancountrieshavealsoactivelyparticipatedintheR&Dandmarketcompetitionofphotoelectricsensors.Thestarttimeofphotoelectricsensorresearchinmycountryisnotfarfromthatintheworld.Hundredsofunitshavebeenworkinginthisfield,mainlyinthefieldsofphotoelectrictemperaturesensors,pressuregauges,flowmeters,liquidlevelgauges,andgalvanometers.Hundredsofscientificresearchresultshavebeenobtained,andsomeReachtheworld'sadvancedlevel.

However,comparedwithdevelopedcountries,thereisstillabiggapinthelevelofresearchinmycountry,whichismainlymanifestedincommercializationandindustrialization.Mostvarietiesarestillintheexperimentaldevelopmentstageandcannotbeputintomassproductionandproduction.Engineeringapplication.

Developmentdirection

Developmentdirectionofproduction

(1)Makephotoelectricsensorsdeveloprapidlyfromtheoreticalresearchtoaone-stopindustrializationmodelofproduction,andtakeindependentinnovationTheleapfrogdevelopmentpathcombinedwithinternationalcooperationhasmademycountryamajorproducerofsensorsintheworld;

(2)Thephotoelectricsensorproductstructureiscomprehensive,coordinated,andsustainable.Productvarietiesshouldbetiltedtowardshightechnologyandhighaddedvalue,especiallytofillthe"blank"varieties;

(3)Theproductionpatternshouldbedevelopedtowardsspecialization.Thatistosay,theproductionofsensorcategoriesissmallandprecise,andacertaintypeofsensorseriesproductsrequiredbyacertainapplicationfieldarespeciallyproducedinordertoobtainahighermarketshare,andthespecializedcooperativeproductionofvarioussensorcompanies;

(4)Themassproductiontechnologyofphotoelectricsensorsisdevelopingtowardsautomation.Therearemanytypesandvarietiesofphotoelectricsensors,andthesensitivematerialsusedaredifferent,whichdeterminesthediversityandcomplexityofsensormanufacturingtechnology.Lookingattheoverviewofthecurrentphotoelectricsensorprocessline,mostprocesseshaveachievedstand-aloneautomation,buttherearestillmanydifficultiesinthefullautomationoftheproductionprocess.ItneedstobewidelyusedinthefuturetomakebreakthroughsbyusingCAD,CAM,advancedautomationequipmentandindustrialrobots;

(5)Thekeytechnologicaltransformationofenterprisesshouldstrengthentheshiftfromrelyingonimportedtechnologytothedirectionofdigestionandabsorptionofimportedtechnologyandindependentinnovation;

(6)EnterprisemanagementshouldacceleratetheshiftfromthedomesticmarkettothemainTheinternationalizationofthecombinationofdomesticandforeignmarketsdevelopsleapsandbounds;

(7)Thecorporatestructurewilldeveloptowardapatternof"large,medium,andsmallsimultaneously"and"groupandspecializedproductioncoexistence"..

Developmentdirectionofresearch

Therapiddevelopmentofphotoelectricsensorsandrelatedtechnologiesmeetsthehigherrequirementsofvariouscontroldevicesandsystems,andmakesthedegreeofautomationinvariousfieldsmoreandmoreThehigher,theimportanceofphotoelectricsensorscontinuestoincreaseatthesametime.Atpresent,themainresearchdirectionsofphotoelectricsensorsare:(1)Multi-purpose.Thatis,aphotoelectricsensorcannotonlytargetonephysicalquantity,butalsomeasuremultiplephysicalquantitiesatthesametime;(2)Developmentofnewsensingmaterials,sensingtechnologies,etc.;(3)Underharshconditions(hightemperature,highpressure,etc.)Thedevelopmentandapplicationoflow-costsensors(connection,installation,etc.);(4)Thedevelopmentofmicro-opticaltechnologycombiningphotoelectricsensorswithothermicro-technology.

Prospects

Thesensormarketreportshowsthattheglobalsensormarketcapacityin2008was50.6billionU.S.dollars,andtheglobalsensormarketisexpectedtoreachover60billionU.S.dollarsin2010.ThesurveyshowsthatEasternEurope,Asia-PacificandCanadahavebecomethefastest-growingregionsinthesensormarket,whiletheUnitedStates,Germany,andJapanarestilltheregionswiththelargestsensormarketdistribution.Asfarastheworldisconcerned,thefastest-growingsensormarketisstilltheautomotivemarket,andtheprocesscontrolmarketisthesecondlargest,whichisoptimisticabouttheprospectsofthecommunicationsmarket.

Somesensormarketssuchaspressuresensors,temperaturesensors,flowsensors,andlevelsensorshaveshownthecharacteristicsofamaturemarket.Themarketsizeofflowsensors,pressuresensors,andtemperaturesensorsisthelargest,accountingfor21%,19%,and14%oftheentiresensormarket,respectively.Themaingrowthofthesensormarketcomesfromemergingsensorssuchaswirelesssensors,MEMS(Micro-Electro-MechanicalSystems)sensors,andbiosensors.Amongthem,thecompoundannualgrowthrateofwirelesssensorsin2007-2010isexpectedtoexceed25%.

Theglobalsensormarketisshowingatrendofrapidgrowthamidever-changinginnovations.Relevantexpertspointedoutthatthemaintechnologyinthesensorfieldwillbeextendedandimprovedontheexistingbasis.Countrieswillcompetetoacceleratethedevelopmentandindustrializationofanewgenerationofsensors,andcompetitionwillbecomeincreasinglyfierce.Thedevelopmentofnewtechnologieswillredefinethefuturesensormarket,suchastheemergenceofnewsensorssuchaswirelesssensors,opticalfibersensors,smartsensors,andmetaloxidesensorsandtheexpansionofmarketshare.

Intelligentdevelopmentofphotoelectricsensors

Intelligentphotoelectricsensorsareahotresearchtopicintheinternationalscienceandtechnologycommunity,andthereisnounifiedandprecisedefinition.Atpresent,scholarsathomeandabroadgenerallybelievethatthesmartphotoelectricsensoriscomposedofatraditionalphotoelectricsensorandamicroprocessor(ormicrocomputer).Adjustitsinternalbehaviortomakethecollecteddatathebest.

Thefunctionsofthesmartphotoelectricsensorare:self-compensationcapability,self-calibrationfunction,self-diagnosisfunction,numericalprocessingfunction,two-waycommunicationfunction,informationstorageandmemoryfunction,digitaloutputfunction.Withthedevelopmentofscienceandtechnology,thefunctionsofsmartsensorswillgraduallyincrease.Itwilluseartificialneuralnetworks,artificialintelligence,andinformationprocessingtechnologies(suchassensorinformationfusiontechnology,fuzzytheory,etc.)toenablesensorstohavemoreadvancedintelligence,analysis,andJudgment,self-adaptation,andself-learningfunctionscancompletecomplextaskssuchasimagerecognition,featuredetection,andmulti-dimensionaldetection.