S5_Apertures&Vignetting

IntroductiontoCODEVAperturesandVignetting•5-1Copyright©2008OpticalResearchAssociates3280EastFoothillBoulevardPasadena,California91107USA(626)795-9101Fax(626)795-0184e-mail:service@opticalres.comWorldWideWeb:http://www.opticalres.comCopyright©2008OpticalResearchAssociatesSection5AperturesandVignettinginCODEVIntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-2WhatIsVignetting?(InCaseYouDidn’tKnow)•Causedbyaperturesonsurfaces,e.g.,IDofaretainingring.–Note:ID=insidediameter,OD=outsidediameter•Theseaperturesclipoff-axisraysnearthepupiledgethatwouldotherwisepassthroughtheaperturestopandhittheimagesurface.•Usefulinreducinglargeoff-axisaberrations(“flare”).•Sometimesnecessarytomeetphysicalrestrictionsinthelens.•Vignettingreducesoff-axisrelativeilluminationintheimage.IntroductiontoCODEVAperturesandVignetting•5-2Copyright©2008OpticalResearchAssociatesIntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-3WhyAreAperturesandVignettingImportantinCODEV?•ThemanydifferentusersandapplicationsofCODEVrequiredifferentapproaches.Examples:–Lenspatentwithnoapertureinformation.Canestimatevignetting,thendetermineappropriateapertures.–Fabricatedlenswithknownapertures.What’sthevignetting?–Needtofitalensinanexistingassemblyorpackagewithknownmechanicalrestrictionssuchasapertures.“Makeitfitinthisbox!”–IRscanningsystem.Coldstopmustbefilled.IntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-4ReferenceRays(ZeroVignettingCase)R1:chiefrayR2:uppermarginalrayR3:lowermarginalrayR4:+xsagittalrayR5:-xsagittalrayEntrancepupilXOBYOBObjectpoint+Y+XR1R2R3R4R5•Defaultaperturesarecalculatedtopassallreferencerays(usingreferencewavelength).•5referenceraysaretracedfromeachfieldpointaccordingtothepupildefinition.Graycellsindicatecalculatedvalue.IntroductiontoCODEVAperturesandVignetting•5-3Copyright©2008OpticalResearchAssociatesIntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-5YOBR1:chiefrayR2:uppermarginalray(usesVUY)R3:lowermarginalray(usesVLY)R4:+xsagittalray(usesVUX)R5:-xsagittalray(usesVLX)XOBObjectpoint+Y+XR1R2R3R4R5VUYVLYVLXVUXEntrancepupilVignettedpupilReferenceRays(PositiveVignettingCase)•Vignettingfactorsareusedifraysareblockedbyuserdefinedaperturesawayfromtheaperturestop.•Resultinnon-circularraybundleattheentrancepupil.•Vignettingfactorscanalsobenegative.IntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-6ReferenceRayAiming•Referencerayaiming(RRAandCRAcommands)canbeusedtodefineareferenceray(R1-R5)byitsintersectiononatargetsurface,ratherthanitspupillocation–Usefulifvignettingfactorswouldchangeduringoptimization•CenterChiefRaybutton:positionsthechiefrayinthecenterofthevignettedraybundle.IntroductiontoCODEVAperturesandVignetting•5-4Copyright©2008OpticalResearchAssociatesIntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-7User-EnteredApertures•Youcanoverridethedefaultwithyourownaperturesofvariousshapes:Circular(CIR)Elliptical(ELX,ELY)Rectangular(REX,REY)•3waystocreatefromGUI:-SurfaceProperties…>Aperture-Review>Apertures-FromLDM(centeredonly)Right-clickRight-clickIntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-81.Restorecooke1.len2.Draw2Dlayout3.Addcircularapertures(clearandedge)toS1,6mmsemi-diameterDemo–SetVignetting**Ifyoumakeanerrorforthesurface#,shape,type,orlabel,youneedtodeleteitandcreateanewone.XYRight-click-or-Left-clickbottomrowtoinsertDouble-clicktochangesurface#,shape,ortypeZIntroductiontoCODEVAperturesandVignetting•5-5Copyright©2008OpticalResearchAssociatesIntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-94.Setvignettinganddrawa2Dlayout5.Addcircularapertures(clearandedge)toS6,6mmsemi-diameter6.Setvignettinganddrawa2DlayoutDemo–SetVignetting!Commands:RESCV_LENS:COOKE1VIE;GOCIRS16;CIREDGS16INCV_MACRO:SETVIGVIE;GOCIRS66;CIREDGS66INCV_MACRO:SETVIGVIE;GO[VerifythevignettingnowmatchesyouraperturesbyzoominginIntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-10ApertureRadiusorDiameter?•IntheGUI,youcansetaflagtoacceptanddisplayfullorsemi-aperturesizes.–Edit>Semi-ApertureMode,or–Tools>Preferences>General>ApertureMode)•Commandsalwaysrefertothesemi-aperture.–UsuallyeasierthanGUIentryCIRSk[CLR|EDG|OBS|HOL][L'label'(3)]radiusREXSk[CLR|EDG|OBS|HOL][L'label'(3)]x_half_rectREYSk[CLR|EDG|OBS|HOL][L'label'(3)]y_half_rectELXSk[CLR|EDG|OBS|HOL][L'label'(3)]x_half_ellELYSk[CLR|EDG|OBS|HOL][L'label'(3)]y_half_ellDELAPESk|Si..j[CLR|EDG|OBS|HOL][L'label'(3)]IntroductiontoCODEVAperturesandVignetting•5-6Copyright©2008OpticalResearchAssociatesIntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-11FourTypesofApertures•Clearaperture–Passesraysinsidetheaperture.–Blocksraysoutsidetheaperture.•Obscuration–Doesthelogicaloppositeofaclearaperture.•Edges/holesonlyusedinNon-sequentialrangesorformodifyingdrawings–Edgeaperture•Definesthephysicalexteriordimensionatthesurface.•Usuallylargerthantheclearaperture!•Canbeusedtohelpfindcorrectrayintersectionsforaspheres.–Hole•Definesthephysicalinteriordimensionatthesurface,i.e.,sizeofhole.IntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-12•2DLensdrawings(VIE,DRA)depictanobscurationasaholeinalensormirror.•3DView(V3D)requiresaholeaperturetodrawanobscurationasaholeApertureTypes-Diagram•Ex.CassegraintelescopeEdgeClearObscuration/holeStopS2IntroductiontoCODEVAperturesandVignetting•5-7Copyright©2008OpticalResearchAssociatesIntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-13ApertureDecenter/Rotation•Anyaperturecanbedecenteredand/orrotatedADXADYAROXYREXREYXY•Shorthandcommandsincludingdecenter/rotation:–CIGradiusadxadyaro–REGx-semi-dimensiony-semi-dimensionadxadyaro–ELGx-semi-axisy-semi-axisadxadyaroIntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-14*Butnotethatpupilaberrationmayresultinnon-zerovignettingaccordingtoCODEV’sdefinition,evenwhenthereisnophysicalvignetting.WhenIstheDefaultUseful?•Becausethedefaultaperturesarecircularanddependonthevignettingfactors,thedefaultoperationismostusefulwhen–Youknowwhatvignettingtouse.(Maybethatmeansnone!*)–Allthefieldsaremeridional.(Ycomponentsonly,noX.)–Thelenshasrotationalsymmetry.•Typicalsuitablesituations:–Cameraandprojectionlenses(CODEV’shistoricalorigin).–Scanlenses(ifscannedinXorYmeridianonly).–Microscopesandtelescopes(objectives,eyepieces,relays).–Zero-fieldsystemssuchaslaseroptics,CDpickups,etc.IntroductiontoCODEVAperturesandVignetting•5-8Copyright©2008OpticalResearchAssociatesIntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-15WhenistheDefaultDangerous?•Systemswithoutrotationalsymmetry.•Systemshavingrectangularlensessuchascylinderlenses.•Off-axissystemssuchasTMAs(three-mirroranastigmats).•Systemswithcompoundfields(bothXandYfieldcomponentsarenon-zero).•Systemsfoldedwithmirrorsorprisms.(Althoughoftenonlytheprismsandmirrorsneednon-defaulttreatment.)IntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-16WhereDoesCODEVUseApertureData?•Apertureinformationisusedtolimitraybundlesorgridsinallanalysisoptionswhichtracegridsofraysacrossthepupil,andmanyotheroptionsaswell(allhighlightedindarkblue).Geometrical>Diffraction>FabricationSupport>System>AlsoLens>EnvironmentalandallFile>Exportoptions.Tolerancing>***(*Apertureswillblockrays,butvignettingfactorsdefinetheraybundlefortheseoptions.)IntroductiontoCODEVAperturesandVignetting•5-9Copyright©2008OpticalResearchAssociatesIntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-17WhenDoesn’tCODEVUseApertureData?•Aperturedataisnotusedinseveralimportantoptions.Generallythevignettingfactorsareusedinstead,unlesstheoptionistracingchiefraysonly.–Analysis>•Diagnostics>–First/Third/FifthOrderAnalysis/Aberrations(ANA,FIO,FIR,FORDERmacro)–RayAberrationCurves(RIM)–GaussianBeamTrace(BEA)–FieldCurves(FIE)•Tolerancing>Distortion(TOD)–Optimization>•AutomaticDesign(exceptMTFoptimization)(AUT)•GlobalSynthesis(AUT;GS)•TestPlateFitting(TES)•ZoomCamDesign(CAM)–1st/3rd-OrderTolerancing(TOL[notinGUI])IntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-18OfParticularInterest...•Display>ViewLens(VIE)–Usesapertureinformationtodrawthelenselements•Size(OD),chamferdiameters,etc.–Vignettingfactorsdeterminewheretheraysaredrawn.–Blockedraysarenotomittedfromdrawingunless“DropCAblocked/obstructedrays”selected.(CABy)•Optimization>AutomaticDesign(AUT)–Tracesitsraygridsinellipticalquadrantswhosesemi-axesarespecifiedbythevignettingfactors.Thisyieldssmootherconvergence,asthesamenumberofraysisalwaystraced.–TheexceptionisMTFoptimization,whichdoesuseapertures.•Analysis>Diagnostics>FootprintPlot(FOO)–Isveryusefulindiagnosingapertureproblems,asweshallsee.IntroductiontoCODEVAperturesandVignetting•5-10Copyright©2008OpticalResearchAssociatesIntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-19IsThereaUser-definedClearApertureontheSurface?CAFlagYesNoUser-definedandUseit.ImposedefaultapertureDefaults(CAYES)DefaultsOnlyIgnoreit.ImposeImposedefaultaperture.(CANO)defaultaperture.User-definedOnlyUseit.Imposenoaperture.*(CAAPE)Noclippingofrays.*ExceptatSTOpsurface,whereadefaultaperturesizedforField1isimposedaswithCAYES.Thisavoidstheunrealisticpossibilityoftotallyunclippedraygrids.WillCODEVUseYourApertures?TheAperturesUsed(CAflag)Setting•Usermustspecifywhethertousedefaultoruser-definedaperture.IntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-20Demo-CAFlag1.Restoresinglet.len.DeletebothsolvesonS2.2.AddcircularclearaperturetoS2,5mmsemi-diameter.3.SetCAflagto“User-DefinedandDefaults”.RunMTF(notegoodMTFfromuserapertureonS2).4.SetCAflagto“DefaultsOnly”.RunMTF(notepoorMTFbecauseuserapertureisignored).5.ChangeapertureonS2to10mmsemi-diameter.6.ReduceEntrancePupilDiameterto10mm.7.SetCAflagto“User-DefinedOnly”.RunMTF(notegoodMTFbecausestopapertureisalwaysimposed).!Commands:RESCV_LENS:SINGLETDELSOLS2CIRS25CAY;MTF;GOCAN;MTF;GOCIRS210;EPD10CAAPE;MTF;GORight-clicknopIntroductiontoCODEVAperturesandVignetting•5-11Copyright©2008OpticalResearchAssociatesIntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-21CAFlagRecommendation***Toensurethedesiredaperturesarebeingusedforanygridcalculation:–Specifyuser-definedaperturesonallsurfaces–AperturesUsed:“User-definedOnly”(CAAPE)IntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-22Aperture-VignettingConsistency•Needtomakesureaperturesandvignettingareconsistentandrepresenttherealworld.ConsistentInconsistentIntroductiontoCODEVAperturesandVignetting•5-12Copyright©2008OpticalResearchAssociatesIntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-23MakingVignettingConsistent•CODEVcan“set”(calculate)thevignettingfactorstomakethemconsistentwiththeapertures:–GUI:Lens>Calculate>SetVignettingData–Command:INCV_MACRO:SETVIG•Youcanalso“set”thePupilSpecification(entrancepupildiameter,numericalapertureinobjectorimagespace,orƒ/number)tobeconsistentwiththeapertures:–GUI:Lens>Calculate>SetPupilSpecification–Command:SETEPD,SETNA,SETNAO,orSETFNO•CODEVcanalso“set”orcreateaperturesforyouthatareconsistentwiththecurrentvignetting:–Mustdeleteexistingaperturestorecalculate–GUI:Lens>Calculate>SetAperturesdialog–Command:SETAPE,SETCAP,SETAAP,SETSAPIntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-24SomePotentialAperturePitfalls•Vignettinginconsistentwithapertures.•Unobtainableornon-physicalvignetting.Noaperturesonexistingsurfacescanclipasdesired.•Cornerclippingwithcompoundfields.•WeirdeffectsinMTForotherdiffractionoptions.•Defaultaperturesnearimages.•LogicallyOR’edapertures.IntroductiontoCODEVAperturesandVignetting•5-13Copyright©2008OpticalResearchAssociatesIntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-25Theserayswillbeclipped.GenerallycanberepairedbySETVIGorbydeletingaperturesandperformingSETAPE(underLens>CalculateintheGUI).VignettingInconsistentwithApertures•Oftenoccurswhenanexistinglenswithaperturesisaltered:–Byoptimization,suchthatelementsmoveorchangediameter.–Bymanuallychangingpupildefinition(e.g.ƒ/number)orfields.•Aperturestakeprecedenceovervignettingfactorsandcliprays.•Canleadtooverlyoptimisticorpessimisticassessmentofimagingperformance(e.g.,MTF)andrelativeillumination.IntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-26UnrealizableVignetting•Unrealizablevignettingoccurswhentherearenodefinableaperturesthatwouldyieldtheindicatedvignetting.•Sometimescanberemediedbyintroducingaperturesonadditionaldummysurfaces.Physically,thiscouldbeamaskorbaffle.Nofeasibleapertureonanexistingsurfacecouldproducethisvignetting.Butaperforatedthinbaffleherecoulddoit.(Clearapertureonadummysurface.)IntroductiontoCODEVAperturesandVignetting•5-14Copyright©2008OpticalResearchAssociatesIntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-27“Corner”ClippingwithCompoundFields•Occurswhentheopticalsystemisrotationallysymmetricorhasonlycircularapertures,andhascompoundfields(simultaneousXandYcomponents).•CausedbyCODEV’suseofonlyfourmarginalreferenceraysforsizingdefaultapertures.•Example(nextslidehasGUIinput):rescv_lens:wideangxan020;yan020incv_macro:unvig!Zerovig.foo;surs1..i-1;dapbla;goWideAngleU.S.Patent2,696,758SURFACE1ORA27-Jul-0739.0MMX=0.000Y=0.000WideAngleU.S.Patent2,696,758SURFACE13ORA27-Jul-0712.8MMX=0.000Y=0.000Clipped“corner”Surface1Surfacei-1ClippingapertureIntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-28“Corner”ClippingGUIInputnoqpIntroductiontoCODEVAperturesandVignetting•5-15Copyright©2008OpticalResearchAssociatesIntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-29•Command:SETCAP(notSETAPE)•GUI:Lens>Calculate>SetApertures“Corner”ClippingRemedySurface1Surfacei-1IntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-30•SymptomiserrormessagefromtheMTFoption:•Errormessageisissuedbecauseoneormoreraysintheedgeroworcolumnpassesthroughtheapertures,suggestingthattheraygridmaybetoosmalltofilltheapertures.•Inthisinstance,lensdrawingandfootprintplotdonotimmediatelyrevealcause.ERROR-Forfield1,wavelength1,raysattheedgeofthepupilmaybeignored.Checkaperturesandvignettingforconsistency.WeirdEffectsinMTF-SymptomFootprintonS1-Nouser-definedapertures.-CAflagsetto“User-DefinedOnly”(CAAPE)soonlyactiveapertureisthestop.IntroductiontoCODEVAperturesandVignetting•5-16Copyright©2008OpticalResearchAssociatesIntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-31IgnoredRaysatthePupilEdge•IftheusertellsCODEVtoonlyuseuser-enteredaperturesandthendoesnotenterany,CODEVassumesanapertureontheStopsurfaceonly–Inthissystem,itallowsanaberratedrayattheedgeofthegridtotracetotheimagesurfaceTheoffendingrayOnlylimitingapertureistheSTOPIntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-32Demo-WeirdMTFDiagnosis1.Restorecooke1.len.Deleteallapertures.SetCAflagto“User-DefinedOnly”.2.RunquickMTF,noteerrormessage.3.CreateapertureonStop,4.4892mmsemi-diameter.IncreaseEPDto26mm(Lens>SystemData…).Thiswillmaintainthecurrentaperturewhileallowingustoseealargerraygrid.Right-clicknoRight-clickpIntroductiontoCODEVAperturesandVignetting•5-17Copyright©2008OpticalResearchAssociatesIntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-33Demo-WeirdMTFDiagnosis4.Draw2Dlayout,22x22raygrid,dropblockedrays.-Noteraysatedgeofgridthatmakeittotheimageplane.5.Runfootprintoption(Analysis>Diagnostics>FootprintPlot),Excludeobscurerays,selectGridmode,#raysacrossdiameter99,showallsurfaces.6.CorrectbycreatinganapertureonS1,7mmsemi-diameter(orCAY).ReduceEPDbackto11.11mm,re-runMTF.\[IntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-34Demo-WeirdMTFDiagnosis!Commands:RESCV_LENS:COOKE1;DELAPESA;CAAPEMTF;GOCIRSS4.4892;EPD26VIE;GRDREC2222;CAB;GOFOO;OBS;BOUN;NRD99;SURS1..I;GOEPD11.11;CIRS17MTF;GOIntroductiontoCODEVAperturesandVignetting•5-18Copyright©2008OpticalResearchAssociatesIntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-35WeirdEffectsinMTF-Remedy•Userhadnoaperturesdefined.•Normally,defaultcircularclearapertureswouldhavepreventedthis,butuserhadsetCAAPE.•Thus,theonlyapertureimposedwasonthestopsurfaceinthereargroup.•Theproblemrayhadgrosssphericalaberrationandwasnotblocked.•REMEDY:UseCAYES.•OtherdiffractionoptionssuchasPSFcangivesimilarerrormessages.•GridinMTFoptionis~25%oversize.Inotherdiffractionoptionsitis100%oversizebydefault,orasdeterminedbytheratioNRD/TGR.IntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-36DefaultAperturesNearImages•Thedefaultaperturesaresizedtopassthereferenceraysatthecenterandedgesofthepupil.•TheassumptionisthatR2throughR5aretheoutermostraysandaresuitablefordeterminingtheappropriatesizeforanaperture.•Nearanintermediateorfinalimage,aberrationsmayinvalidatethisassumption.–Oftenhappensinsystemswithareticle,faceplate,orplaten.•Effectsareattheoutermostfieldonly:–Bogusimagequality(maynotbeobvious)–Lowrelativeillumination(maybeobvious)Defaultaperturesetatmaxreferencerayheight.Raysabovethisareblocked.ReferenceraysinblueIntroductiontoCODEVAperturesandVignetting•5-19Copyright©2008OpticalResearchAssociatesIntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-37DefaultAperturesNearImages(cont.)•Thetransverseaberration(RIM)plotmaylookinnocuous,butactuallyholdsaclue,ifR1,R2,andR3allfallbelowsomepartofthetangentialcurve(forimageheight>0).•Afootprintplot(FOO)atthestopsurfaceinthegridmode(BOUN),lastfieldonly,makestheproblemobvious.•Solution:UseCAAPE,ifappropriate,orputanoversizedaperture(e.g.10%larger)ontheoffendingsurface.CIRSI-11.1*(SDSI-1)worksfineinthisexample.Y=0.000Largeportionofpupilisblocked!-0.05000.0500TANGENTIAL1.00RELATIVEFIELDHEIGHT(20.00)OR1R3R2Raysaboveaxiswillbeblocked.IntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-38Apertures-LogicalCombinations•NormalcombinationofmultipleclearaperturesislogicalAND.–Topass,araymustfallinsidealltheclearaperturesonasurface.–Example:Circlewithflatsontwosides.CIRS1L’A’5;REX3;REY6TruncatedCircularApertureSURFACE1ORA24-Jan-001.25MMX=0.000Y=0.000IntroductiontoCODEVAperturesandVignetting•5-20Copyright©2008OpticalResearchAssociatesIntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-39HexagonAperture•Foraregularhexagonaperture,overlapthreerectangles:REGS1L'A'1.7322000REGS1L'B'1.732200120REGS1L'C'1.732200-120•Note:1.732=√3•TheseaperturesareANDedxy-Restoresinglet.len-AddhexagonalaperturetoS1-VerifywithfootprintplotExercise:IntroductiontoCODEVTraining,“AperturesandVignetting,”Slide5-40LogicallyOR’edApertures•Forsomeshapes,ANDingwon’tdothejob:–Race