>> P.285
Glossary1.N.A.(NumericalAperture)N.A.determinesresolvingpower,depthofeld,andluminosityoftheimage.ThelargertheN.A.thehigheristheresolvingpowerandsmalleristhedepthofeld.N.A.=n•Sinθ7.F(FocalLength)Distancebetweenaprincipalpointandafocalpoint.f1isthefocallengthofanobjective,f2isthefocallengthofatubelens.Magnicationisdeterminedbytheratioofthefocallengthofthetubelenstothatoftheobjective.(Foraninnity-correctedopticalsystem.)nistheindexofrefractionofthemediuminwhichthelensisworking.n=1.0forair.θisthehalf-angleofthemaximumconeoflightthatcanenterorexitthelens.ObjectiveMagnificationofobjective=FocallengthoftubelensFocallengthofobjective(E.g.)1X=200(mm)200(mm)(E.g.)10X=200(mm)20(mm)θAir(n=1)WorkpieceStageglass2.R(ResolvingPower)Minimumdistancebetweenpointsorlinesthatarejustdistinguishableasseparateentities.ResolvingpowerisdeterminedbyN.A.andwavelengthλ.R(µm)=λ2·N.A.3.W.D.(WorkingDistance)Distancebetweenthesurfaceofthespecimenandthefrontfaceoftheobjectivewheninfocus.8.FieldNumberandFOV(RealFieldofView)Theeldnumberofaneyepieceisdeterminedbytheeldstopdiameteroftheeyepieceanditisexpressedinmm.FOVistheareaofspecimenobservableandisdeterminedbytheeldnumberoftheeyepieceandmagnicationoftheobjective.FOV(mm)=FieldnumberofeyepieceMagnificationofobjective(E.g.Usinganeyepieceoffieldnumber24)FOVfor1Xobjective=FOVfor10Xobjective=241=ø24(mm)2410=ø2.4(mm)4.ParfocalizingDistanceDistancebetweenthesurfaceofthespecimenandtheobjective'sseatingsurfacewheninfocus.AreaofspecimenobservableonTVmonitorAreaofspecimenobservableonTVmonitor=Areaofcameraimageelement(VxH)MagnificationofobjectiveIndicationmagnicationonTVmonitorParfocalizingdistanceWorkingdistanceIndicationmagnificationonTVmonitor=MagnificationofobjectivexDiagonallinelengthofmonitorindicationDiagonallinelengthofcameraimageelement5.Innity-correctedopticalsystemAnopticalsysteminwhichtheimageisformedbyanobjectiveandatubelenswithan'InnitySpace'betweenthem,intowhichopticalaccessoriescanbeinserted.InfinityspaceObjectiveObjectivefocalpoint(objectplane)Imaging(tube)lensImaginglensfocalpoint(imageplane)Note:Sizeofcameraimageelement(VxHxDiagonal)1/3inchimageelement:3.6x4.8x6.0mm2/3inchimageelement:6.6x8.8x11.0mm1/2inchimageelement:4.8x6.4x8.0mm9.DOF(DepthofField)Verticaldistanceinthespecimen,measuredfromaboveandbelowtheexactplaneoffocus,whichstillyieldsanacceptableimage.ThelargertheN.A.,thesmallerthedepthofeld.f1f2Magnification=f2/f1Eyepieceobservation(FormuladuetoBerek)6.Finite-correctedopticalsystemAnopticalsysteminwhichtheimageisformedonlybyanobjectivelens.ObjectiveObjectpointImagepointL1L2Magnification=L2/L1±DOF(µm)=ωx250.000N.A.xM+λ2x(N.A.)2λ=Standardwavelength(550nm)ω:Resolutionofhumaneye(Visualangle:5minute)M:Totalmagnification(Objectivemag.xEyepiecemag.)TVmonitorobservation±DOF(µm)=λ2x(N.A.)2λ=Standardwavelength(550nm)7-28
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