I-athikili Izinsimbi zokubona iso lomuntu
Izingxenye zeso
I-cornea iyi-membrane ecacile neqinile emboze ingaphambili leso. I-cornea iguqula ukukhanya okungena esweni.
Impunzi iyingxenye emnyama yeso. Impunzi imnyama, ngakho-ke imunca cishe konke ukukhanya. Impunzi iyimbobo lapho ukukhanya kudlula khona esweni. Uma ububanzi bompunzi bukhulu, ukukhanya okuningi kungena esweni futhi uma ubukhulu bompunzi buncane, ukukhanya okuncane kungena esweni.
I-iris ilawula ubukhulu be-pupil. Uma indawo ezungeze iso ikhanya kakhulu, i-iris inciphisa i-pupil. Ngokuphambene nalokho, lapho indawo ezungeze amehlo ingakhanyi kangako, i-iris ikhulisa i-pupil ukuze inani lokukhanya elingena esweni libe likhulu. Uma uke wabona umehluko phakathi kweso lekati emini nasebusuku, khona-ke ungaqonda kalula umsebenzi we-iris.
Imisipha ye-ciliary isebenza ukushintsha ukugoba kwelensi yeso. Izinguquko kulensi yeso zithinta ubude be-focal lens yeso. Uma iso libona izinto kude kakhulu, imisipha ye-ciliary iyakhululeka ukuze i-radius ye-lens curve ikhule futhi ubude be-focal lens bukhule.
Uma iso libheka izinto eduze, imisipha ye-ciliary iyafinyela ukuze i-radius ye-lens curve inciphe kanye nobude be-focal lens bunciphe. Ngakho-ke, ngokungaqondile, umsebenzi wemisipha ye-ciliary ukulawula ubude be-focal lens yeso ukuze iso likwazi ukugxila esithombeni sento ngendlela efanele. Ushintsho kubude be-focal ye-eyepiece lubizwa ngokuthi i-eye accommodation.
Ilensi yeso iyilensi ehambisanayo noma ilensi eqondile noma ilensi enhle. Nakuba kwenzeka ukujikijelwa kokukhanya okwengeziwe ku-cornea, ilensi yeso nayo iyajikijelwa futhi igxilise umsebe wokukhanya ukuze isithombe sakheke ngqo ku-retina. Isithombe kumele sakheke ku-retina ukuze izinto zibonakale kahle. I-retina isebenza ukuguqula amaza okukhanya abe amasignali kagesi, abese edlula emsipheni we-optic aye ebuchosheni.
Indawo yokuhlala ngeso elivamile
Ukulungiswa kwamehlo ukulungiswa kobude be-focal (f) belensi yeso nebanga lento eliso ukuze isithombe sikwazi ukugxila ku-retina. Ubude be-focal belensi yeso yibanga eliphakathi kwelensi yeso kanye nendawo egxile kulensi (F). Uma iso livumela, ukugoba kwelensi yeso kuyashintsha, okubangela ukuthi i-radius yokugoba kwelensi yeso ishintshe futhi ngenxa yalokho ubude be-focal belensi yeso bushintshe.
Uma iso libona into ekude, imisipha ye-ciliary iyakhululeka, okwenza ilensi yeso ibe yisicaba ukuze i-radius yokugoba kanye nobude be-focal lens kukhule. Iphuzu elikude yibanga elide kakhulu iso elingagxila kulo, lapho iphuzu elikude leso elivamile lingenamkhawulo. Lapho imisipha ye-ciliary ikhululeka ukuze ubude be-focal lens yeso bube bude futhi bukwazi ukugxila entweni ekude, iso liba nendawo encane yokuhlala.
Uma iso libona izinto ziseduze, imisipha ye-ciliary iyafinyela, okwenza ilensi yeso igobe kakhulu ukuze i-radius yokugoba kanye nobude be-focal lens yehle. Ibanga lento eya esweni eliseduze elingasagxilwa yiso libizwa ngokuthi iphuzu eliseduze. Umuntu ojwayelekile unephuzu eliseduze elingama-25 cm. Lapho imisipha ye-ciliary ifinyela ukuze ubude be-focal lens yeso bube bufushane futhi bukwazi ukugxila entweni eseduze (25 cm), iso linendawo yokuhlala ephezulu.
Ukwakheka kwesithombe
Iphuzu elikude
Uma into ingenamkhawulo, ilensi yeso iphenduka ibe yi-flat kuze kube yilapho ubude be-focal (f) belensi bulingana nebanga lesithombe (di). Ibanga lesithombe liyibanga eliphakathi kwelensi nendawo lapho umsebe wokukhanya uphambukiswa khona yiso. Iphuzu lapho imisebe yokukhanya ihlangana khona, ihambisana ne-retina. Ngakho-ke kungaphethwa ngokuthi lapho iso libona into engenamkhawulo, ukugoba kwelensi yeso kuphenduka kube yi-flat kuze kube yilapho ubude be-focal belensi (f) bulingana nebanga eliphakathi kwelensi ne-retina. Umsebe wokukhanya kumele uhlangane ne-retina ukuze ukukhanya kuguqulwe kube izimpawu zikagesi ku-retina.
Lokhu okulandelayo kuwubufakazi bezibalo bokuthi kungani uma into ingaphakathi, ubude be-focal belensi (f) bulingana nebanga lesithombe (di). Ubudlelwano phakathi kobude be-focal (f), ibanga lento (do) kanye nebanga lesithombe (di) buvezwa nge-equation elandelayo.
1/f = 1/yenza + 1/di —– Isibalo 1
Ilensi yeso ilensi ehlanganayo. Ngakho-ke, ubude be-focal (f) buyi-positive. Ibanga lento (do) alinamkhawulo, ngakho-ke faka uphawu lwe-infinity esikhundleni sebanga lento (do) ku-equation 1.
1/f = 1/~ + 1/di
1/f = 0 + 1/di
1/f = 1/di
di = f —– Isibalo 2
Isibalo 2 sibonisa ukuthi kumalensi ahlanganayo uma into ingaphakathi, ubude be-focal (f) bulingana nebanga lesithombe (di).
Iphuzu eliseduze
Kuthiwani uma into iseduze neso? Ngaphambilini, kwachazwa ukuthi indawo eseduze yeso elivamile noma ibanga lento eseduze engagxilwa kahle yiso elivamile lingu-25 cm. Ngakho-ke, ubude be-focal (f) belensi yeso kumele bube buncane kunebanga lento (do) elingu-25 cm. Ubude be-focal belensi yeso kumele bube buncane kunebanga elingu-25 cm ukuze ilensi yeso ikhiqize isithombe sangempela. Ilensi yeso ilensi e-convex engakha isithombe esibonakalayo kanye nesithombe sangempela. Isithombe sangempela sikhiqizwa ilensi e-convex lapho ubude be-focal (f) buncane kunebanga lento (do). Lokhu kuxoxwe ngakho esihlokweni sokwakheka kwesithombe selensi e-convex.
Linganisa ubude be-focal (f) besistimu yelensi yeso:
Iphuzu eliseduze leso elivamile lingu-25 cm ukuze ibanga lento eseduze libe ngu-25 cm. Ibanga eliphakathi kwe-cornea ne-retina lingaba ngu-2.5 cm. Isithombe sicacile uma ukukhanya kwehlela ku-retina ukuze ibanga eliphakathi kwe-cornea ne-retina libhekwe njengebanga lesithombe (di). Ngakho-ke, ibanga lesithombe (in) lingu-2.5 cm.
1/f = 1/do + 1/di
1/f = 1/25 + 1/2.5 = 1/25 + 10/25 = 11/25
f = 25/11
f = 2.27 cm
Ngokusekelwe emiphumeleni yezibalo ezingenhla, kungaphethwa ngokuthi ubude be-focal (f) buncane kunebanga lesithombe (di). Umehluko phakathi kwebanga lesithombe (di) nobude be-focal (f) ngu-2.5 cm – 2.27 cm = 0.23 cm. Indawo egxile ohlelweni lwelensi ye-cornea-eye ingu-0.23 cm ngakwesobunxele sesithombe noma i-retina.
Uhlelo lwelensi ye-cornea-eye luyilensi egobile ukuze isithombe sakheke ku-retina yize singokoqobo kodwa siguqukile. Ngisho noma isithombe ku-retina siguqukile, inzwa yobuchopho iyiphendula iqonde phezulu.
