《应用光学》PPT课件.ppt

Insec 4 3wehavementionedthatinordertokeeptheangleoftwomirrorsunchanged thetwomirrorsareusuallymadeonacommonglass 4 4prism 棱镜 anditsunfolding 展开 Thesekindsofopticalelementsarecalledprisms Theprisminfig 4 9iscalledPentaprism 五角棱镜 Fig 4 10showstheappearanceofaright angleprism Itisatrianglecylinder 三角柱体 Theplaneorsectionwhichisperpendiculartoeachprismiscalledmainsection 主截面 Therayslieinthemainsectionwillliestillinthesamesectionafterpassingthroughtheprism Fig 4 10 Basicdefinition B A C Opticalaxis ABC LengthofABC AB BCGeometricallengthofaxis Incidentface ACEmergingface BCWorkingface AC BC ABRidge楞 theintersectionlineofworkingfaceMainsection 主截面 光轴截面 ABCface B A C Opticalaxis themiddlelineofworkingfacePrincipalsection 2 ComplexPrism Equivalentactionofprism F F F Incidentface Emergingface F F Incidentface Emergingface Conclusion Equivalentactionofaprisminopticalsystemcorrespondswithaparellelglassboard 平行平板 unfoldingofprism Thismethod unfoldingtheprism cancelingthereflectionandreplacingprism srefractionsbyglassblock srefraction iscalledprismunfolding 把棱镜的光轴截面沿着它的反射面展开 取消棱镜的反射 以平行玻璃板的折射代替棱镜折射的方法称为 棱镜的展开 Theprismmustbedemandedtomeettworequirements Afterunfoldingtheprism thetwofacesoftheglassblockmustbeparalleltoeachother 棱镜展开后玻璃板的两个表面必须平行 Whentheprismlocatesinconvergingrays theaxismustbeperpendiculartobothincidentandemergentfaces 如果棱镜位于会聚光束中 则光轴必须和棱镜的入射及出射表面相垂直 Methodsofunfolding 按入射光线的顺序 以反射面为镜面 求其对称像 并依次画出反射棱镜的展开图 简单说 逐个作出棱镜经反射面所成的像 A B C O S S C Example1 C A B B A S S S Example2 Sometipicalprisms 4 4 1Right angleprism Theright angleprismcandeviatetheaxisthroughanyangle Fig 4 1 90 2 deviatedtheaxisthrough Fig 4 2Isoscelesprism 4 4 2Pentaprism 五角棱镜 L thelengthoftheaxis光轴长度 D Themaximumaperture通光口径 90 4 5roofsurfacesandroofprisms 屋脊面和屋脊棱镜 Right angleprism Roofprism 两个互相垂直的反射面称为屋脊面 Inordertogetanimagesimilartotheobject twosurfacesat90 whoseintersectionliesinthehypotenuse 斜边 canbeusedtoreplaceoneofthereflectingsurfaces Thesespecialsurfacesarecalledroofsurfaces 屋脊面 Aprismcontainingroofsurfacesiscalledroofprism 屋脊棱镜 Whatistheroleoftheroofprism Theadditionoftherooftotheprismistointroduceanextrainversiontotheimageorchangethetotalreflectingnumberfromoddtoeven keeptheoriginalaxisandimageorientationinthemainsectionunchanged Inthiswaywecanaddareflectionandgetanimagesimilartotheobject 在不改变光轴方向和主截面内成像方向的条件下 使像倒置一次 或使系统总的反射次数由奇数变成偶数 从而达到物像相似的要求 Fig 4 18Principleofroofsurface Planardonationmethodofroomprism屋脊棱镜的平面表示方法 4 6imagingpropertyofparallelglassblockandprismsizecalculation Wementionedintheprevioussectionthatbyusingaprismtoreplacemirrorscorrespondstoaddaparallelglassblock Fig 4 21Parallelglassblock Thatmeansaparallelglassblockonlymakestheimageplaneshiftacertaindistance havingnoinfluenceontheimagingproperty Theequivalentairthickness 4 2 光线移动的距离随入射角的不同而不同同样也随平板的厚度不同而变化 上式表明 L 因不同的I1值不同而不同 即从具有不同入射角的各条光线经平行平面板折射后 具有不同的轴向位移量 这就说明 同心光束经平行平面板后变为非同心光束 成像是不完善的 也可以看出平行平面板的厚度d愈大 成像不完善程度也愈大 4 7determinationofimageorientationsformirrorsandprisms y z x Fig 4 25 a 4 7 1mirrorandprismsystemwithsinglemainsection mirrorandprismsystemwithsinglemainsectionmeansthatallofthemainsectionsofthemirrorsandprismscoincidewithoneanother Ifthereisnoroofsurfaceinthesystemtheorientationofzwhichisnormaltothemainsectionwillbeparalleltoallofthereflectingsurfaces Accordingtothemirrorimagingproperties theobjectandtheimagearesymmetricaltothemirror sotheorientationofz inimagespacewillbeasthesameasthatofzintheobjectspacenomatterhowmanyreflectionshavehappened However ifthereisaroofsurfaceinthesystem accordingtotheroofsurfaceproperty theorientationsz andzwillbereversed Inthiswaywecaneasilydeterminetheorientationofz inamirrorandprismsystemwiththesinglemainsection Firstofall supposethereisnoroofsurfacesinthesystemandmeansz willbethesameorientationasz onthiscondition ifthetotalnumberofthereflectorsiseven theimagewillbesimilartotheobject y andyhavethesameorientationiftheorientationofaxisx coincideswithx asshowninfig 4 25 a Onthecontrary iftheorientationofaxisx isreversedtox y willbeoppositetoy asshowninfig 4 25 b Similarly ifthetotalnumberofthereflectorsisodd theimagewillbeamirrorimage y andyhavetheoppositeorientationofaxisx coincideswithx asshowninfig 4 26 a Onthecontrary iftheorientationoftheaxisx isreversedtox y willhavethesameorientationasy asshowninfig 4 26 b Thus foramirrorandprismsystemwithsinglemainsectionwecangetthefollowingrules asshownintable4 2 Table4 2orientationrulesfory 总结判断单一主截面的平面镜棱镜系统中 主截面内成像的方向规则如下 1 光轴同向 光轴反射次数为偶数 y和y 同向 光轴反射次数为奇数时 y和y 反向 2 光轴反向 光轴反射次数为偶数 y和y 反向 光轴反射次数为奇时 y和y 同向 注意 1 上面提到的光轴 同向和反向是广义的 同向不仅仅指入射光轴和出射光轴平行 凡是光轴偏转角小于90均认为是同向的 大于90认为是反向的 2 当系统中有屋脊棱镜时 不影响主截面内像方向 光轴看成是在棱上反射 计算光轴反射时只计算一次 计算总反射次数时 屋脊面计算两次 Ifthereisaroofsurfaceinthesystem accordingtoitsimagingproperty itdoesnotaffecttheorientationswhichlieinthemansection thus onthisconditiontheaboverulescanalsobeused Fortheroofsurfacetheaxiscanbetakenasifitisreflectedattherooflineandthereflectornumbershouldbecountedasontime However forthetotalnumberofreflectors theroofsurfaceshouldbecountedtwice 方法1 x x 与光轴同向 2 没有或偶数屋脊面时 z 与z同向 奇数屋脊面时 z 与z反向 3 当x 与x同向时 偶次反射y 与y同向 奇次反射y 与y反向 x 与x反向时 偶次反射y 与y反向 奇次反射y 与y同向 ExampleA FIG 4 27 a b y z x y z x y z x y z x 8 Similariamge 7 mirroriamge Fig 4 27 4 7 2Mirrorandprismsystemwithtwomainsectionsperpendiculartoeachther 1 2 3 o1 o2 o3 o4 y x z y z x 1 3 2 Similarimage Fig 4 28 1 2 3 o1 o2 o3 o4 y x z y z x 1 3 2 o1 o2 o3 o4 Forprism1and3 Theaxisrotates180 sox andxisreversed Themumberofreflectoris2 yandy isreversed Forprism2 T