Имагингфеатурес
Firstputtheobjectfarawayfromthelens,checkthepositionandsizeoftheimage,thenmovetheobjecttotheconvexlens,andthencheckthesizeandpositionoftheimageVariety.Itcanbeseenfromtheexperiment:
(1)Када је објекат веома удаљен, слика се рађа без фокуса, а слика је веома мала.
(2)Whentheobjectmovestothefrontoftheconvexlens,theimagemovesfromthefocalpointtotheoutsideoftheconvexlens,theimagebecomeslargerandupsidedown.
(3) Када објекат није удаљен од фокуса, слика је веома удаљена, а слика је веома велика.
(4)Објекат је у фокусу, а слика није пронађена, није снимљена.
(5)Theobjectcannotbeimagedinthefocalpoint,buttheeyecanseeamagnifieduprightvirtualimagethroughthelens.
Тхеимагинг принципофмагнифиинггласс
Anopticallensmadeofglassorothertransparentmaterialswithacurvedsurfacecanmagnifyandimageanobject.TheopticalpathdiagramisshowninFigure1.TheobjectABlocatedwithinthefocusFoftheobjectsidehasasizeofy,anditismagnifiedintoavirtualimageA'B'ofsizey'.ThemagnificationofthemagnifyingglassΓ=250/f'where250--thedistanceoftheclearvision,inmmf'--thefocallengthofthemagnifyingglass,inmmThemagnificationreferstotheimageoftheobjectobservedbythemagnifyingglasswithinadistanceof250mmTheratiooftheviewingangletotheviewingangleofanobjectobservedwithoutamagnifyingglass.1.Drawastraightruler2.DrawapointOontheruler,whichistheopticalcenter,anddrawaconvexlensattheOpoint.Marktheone-timefocallengthpointfandthetwo-timefocallengthpoint2fonbothsidesoftheconvexlens.
3. Преграда је подељена на три области на левој и десној страниконвексног сочива.
4.Закон:
Када објектизује бесконачност, фокусирајте се на тачку.
Ствари три (површина) су попут две (површине) мале реално обрнуте
Ствари две (област) као три (површина) су обрнуте велике
Area)Onthesamesideoftheimage,thepositiveandlargevirtualimage
The2Fpointisthedividingpointoftheenlargedandreducedimage
TheFpointisthedividingpointofthevirtualimageoftherealimage.
Веусеарулер при примени и памћењу:
Тхеимагинг принципеофамицросцопе
Microscopeandmagnifyingglassplaythesamerole,thatis,toremovesmallobjectsnearbyIntoamagnifiedimageforhumaneyestoobserve.It'sjustthatamicroscopecanhaveahighermagnificationthanamagnifyingglass.Schematicdiagramofanobjectbeingimagedbyamicroscope.Fortheconvenienceofcalculation,boththeobjectivelensL1andtheeyepieceL2arerepresentedbyasinglelens.TheobjectABislocatedinfrontoftheobjectivelens,andthedistancefromtheobjectivelensisgreaterthanthefocallengthoftheobjectivelens,butlessthantwicethefocallengthoftheobjectivelens.Therefore,afteritpassesthroughtheobjectivelens,itwillinevitablyformaninvertedenlargedrealimageA'B'.A'B'islocatedontheobjectivefocalpointF2oftheeyepiece,orveryclosetoF2.ThenitismagnifiedbytheeyepieceintoavirtualimageA''B''foreyeobservation.ThepositionofthevirtualimageA''B''dependsonthedistancebetweenF2andA'B'.Itcanbeatinfinity(whenA'B'isonF2)orattheobserver'sphotopicdistance(WhenA'B'istotherightoffocusF2inthefigure).Theeyepiecehasthesamefunctionasamagnifyingglass.Thedifferenceisthatwhattheeyeseesthroughtheeyepieceisnottheobjectitself,buttheimageoftheobjectthathasbeenmagnifiedoncebytheobjectivelens.
Импортанттоптицалтецхницалпараметерс
Duringmicroscopicexamination,peoplealwayshopetohaveaclearandbrightidealimage,whichrequirestheopticaltechnicalparametersofthemicroscopetoreachcertainstandardsAnditisrequiredthatwheninuse,therelationshipbetweenthevariousparametersmustbecoordinatedaccordingtothepurposeofthemicroscopyandtheactualsituation.Onlyinthiswaycanwegivefullplaytotheproperperformanceofthemicroscopeandobtainsatisfactorymicroscopicexaminationresults.Theopticaltechnicalparametersofthemicroscopeinclude:numericalaperture,resolution,magnification,depthoffocus,fieldofviewwidth,coveragedifference,workingdistance,andsoon.Theseparametersarenotallashighaspossible.Theyareinterrelatedandrestricteachother.Inuse,therelationshipbetweentheparametersshouldbecoordinatedaccordingtothepurposeofmicroscopyandtheactualsituation,buttheresolutionshouldbeguaranteed..
1.NumericalApertureNumericalapertureisabbreviatedNA.Numericalapertureisthemaintechnicalparameterofobjectivelensandcondenserlens,anditisanimportantindicatorofjudgingtheperformanceofboth(especiallyforobjectivelens).Thenumericalvalueismarkedontheshelloftheobjectivelensandcondenserlensrespectively.Thenumericalaperture(NA)istheproductoftherefractiveindex(n)ofthemediumbetweenthefrontlensoftheobjectivelensandtheinspectedobjectandthehalfsineoftheapertureangle(u).Theformulaisasfollows:NA=nsinu/2Theapertureangleisalsocalled"lensangle",whichistheangleformedbytheobjectpointontheopticalaxisoftheobjectivelensandtheeffectivediameterofthefrontlensoftheobjectivelens.Thelargertheapertureangle,thebrighterthelightenteringtheobjectivelens,whichisproportionaltotheeffectivediameteroftheobjectivelensandinverselyproportionaltothedistanceofthefocalpoint.Duringmicroscopeobservation,ifyouwanttoincreasetheNAvalue,theapertureanglecannotbeincreased.Theonlywayistoincreasetherefractiveindexnofthemedium.Basedonthisprinciple,awaterimmersionobjectivelensandanoilimmersionobjectivelensareproduced.Becausetherefractiveindexnofthemediumisgreaterthan1,theNAvaluecanbegreaterthan1.Themaximumnumericalapertureis1.4,whichhasreachedthelimittheoreticallyandtechnically.Therefractiveindexofbromonaphthaleneis1.66,sotheNAvaluecanbegreaterthan1.4.Itmustbepointedoutherethatinordertogivefullplaytotheroleoftheobjectivelensnumericalaperture,theNAvalueofthecondenserlensshouldbeequaltoorslightlygreaterthantheNAvalueoftheobjectivelensduringobservation.Numericalaperturehasacloserelationshipwithothertechnicalparameters,italmostdeterminesandaffectsothertechnicalparameters.Itisproportionaltotheresolution,proportionaltothemagnification,andinverselyproportionaltothedepthoffocus.AstheNAvalueincreases,thewidthofthefieldofviewandtheworkingdistancewilldecreaseaccordingly.
2.ResolutionTheresolutionofamicroscopereferstotheminimumdistancebetweentwoobjectpointsthatcanbeclearlydistinguishedbythemicroscope,alsoknownasthe"discriminationrate".Thecalculationformulaisσ=λ/NAwhereσistheminimumresolutiondistance;λisthewavelengthoflight;NAisthenumericalapertureoftheobjectivelens.Itcanbeseenthattheresolutionoftheobjectivelensisdeterminedbytwofactors,theNAvalueoftheobjectivelensandthewavelengthoftheilluminatinglightsource.ThelargertheNAvalue,theshorterthewavelengthoftheilluminatinglight,andthesmallertheσvalue,thehighertheresolution.Toimprovetheresolution,thatis,reducethevalueofσ,thefollowingmeasurescanbetaken(1)Reducethevalueofwavelengthλanduseashort-wavelengthlightsource.(2)IncreasethevalueofmediumntoincreasethevalueofNA(NA=nsinu/2).(3)IncreasetheapertureangleuvaluetoincreasetheNAvalue.(4)Increasethecontrastbetweenlightanddark.
3.MagnificationandeffectivemagnificationDuetothetwomagnificationsoftheobjectivelensandtheeyepiece,theoverallmicroscopeThemagnificationΓshouldbetheproductoftheobjectivelensmagnificationβandtheeyepiecemagnificationΓ1:Γ=βΓ1Obviously,comparedwithamagnifyingglass,amicroscopecanhaveamuchhighermagnification,anditcanbeconvenienttoexchangeobjectivesandeyepieceswithdifferentmagnificationsChangethemagnificationofthemicroscope.Themagnificationisalsoanimportantparameterofthemicroscope,butyoushouldnotblindlybelievethatthehigherthemagnification,thebetter.Thelimitofmicroscopemagnificationistheeffectivemagnification.Resolutionandmagnificationaretwodifferentbutrelatedconcepts.Thereisarelationship:500NAnumericalapertureisnotlargeenough,thatis,whentheresolutionisnothighenough,themicroscopecannotdistinguishthefinestructureoftheobject.Atthistime,evenifthemagnificationisincreasedexcessively,theresultcanonlybealargeoutlinebutuncleardetailsTheimageiscalledinvalidmagnification.Conversely,iftheresolutionhasmettherequirementsandthemagnificationisinsufficient,themicroscopehastheabilitytodistinguish,buttheimageistoosmalltobeclearlyseenbythehumaneye.Therefore,inordertogivefullplaytotheresolvingpowerofthemicroscope,thenumericalapertureshouldbereasonablymatchedwiththetotalmagnificationofthemicroscope.
4.DepthoffocusDepthoffocusistheabbreviationofdepthoffocus,thatis,whenusingamicroscope,whenthefocusisonacertainobject,notonlyisitlocatedontheplaneofthepointEverypointcanbeseenclearly,andwithinacertainthicknessaboveandbelowtheplane,itcanalsobeseenclearly.Thethicknessofthisclearpartisthedepthoffocus.Ifthefocaldepthislarge,youcanseethewholelayeroftheobjecttobeinspected,whileifthefocaldepthissmall,youcanonlyseeathinlayeroftheobjecttobeinspected.Thefocaldepthhasthefollowingrelationshipwithothertechnicalparameters:
(1)Thedepthoffocusisinverselyproportionaltothetotalmagnificationandthenumericalapertureoftheobjectivelens.
(2)Thedepthoffocusislargeandtheresolutionisreduced.Duetothelargedepthoffieldofthelow-magnificationobjectivelens,itcausesdifficultieswhentakingpictureswiththelow-magnificationobjectivelens.Itwillbeintroducedindetailinthephotomicrograph.
5.FieldofView(FieldOfView)Whenobservingamicroscope,thebrightcircularareaseeniscalledthefieldofview.Itssizeisdeterminedbytheviewintheeyepiece.Determinedbythefielddiaphragm.Thefieldofviewdiameterisalsocalledthefieldofviewwidth,whichreferstotheactualrangeoftheobjecttobeinspectedinthecircularfieldofviewseenunderthemicroscope.Thelargerthediameterofthefieldofview,theeasieritistoobserve.ThereisaformulaF=FN/βwhereF:fieldofviewdiameter,FN:fieldnumber(FieldNumber,abbreviatedasFN,markedontheoutsideoftheeyepiecelensbarrel),β:objectivelensmagnification.Itcanbeseenfromtheformula:
(1)Thediameterofthefieldofviewisdirectlyproportionaltothenumberoffieldsofview.
(2)Increasethemultipleoftheobjectivelens,thediameterofthefieldofviewwilldecrease.Therefore,ifyoucanseethewholepictureoftheobjectunderinspectionwithalowmagnificationlens,youcanonlyseeasmallpartoftheobjectunderinspectionwithahighmagnificationobjectivelens.
6.PoorcoverageTheopticalsystemofthemicroscopealsoincludesthecoverglass.Becausethethicknessofthecoverglassisnotstandard,thelightpathafterthelightenterstheairfromthecoverglassischanged,resultinginaphasedifference,whichisthecoveragedifference.Poorcoverageaffectsthesoundqualityofthemicroscope.Internationally,thestandardthicknessofthecoverglassis0.17mm,andthepermittedrangeis0.16-0.18mm.Thedifferenceinthisthicknessrangehasbeencalculatedinthemanufactureoftheobjectivelens.The0.17ontheobjectivelensshellindicatesthethicknessofthecoverglassrequiredbytheobjectivelens.
7.WorkingdistanceWDworkingdistanceisalsocalledobjectdistance
Itreferstothedistancebetweenthesurfaceofthefrontlensoftheobjectivelensandtheobjecttobeinspected.