Izinto zokusetshenziswa kwamehlo ezibonakalayo
Iso liyithuluzi elibonakalayo elitholakala kubantu. Likuvumela ukuthi ufunde isihloko sefiziksi ๐ noma ubheke ubuso besoka elihle noma elihle ๐ Kuthiwani uma amehlo akho engasebenzi kahle? Ngokuqinisekile uyazi impendulo yalo mbuzo. Ngakho-ke, bonga uma usenamehlo aphilile futhi ubona kahle. Umuntu oyimpumputhe ngokuqinisekile akakwazi ukubona futhi angacabanga ngesimo sezwe esiphila kulo namuhla.
Ukuba namehlo anempilo futhi asebenza kahle kuyithemba lawo wonke umuntu. Kodwa-ke, iqiniso ngezinye izikhathi alifinyeleli okulindelwe. Abanye abantu bahloselwe ukubhekana nokungasebenzi kahle kwamehlo, okubavimbela ukubona kahle. Intuthuko kwezesayensi, ikakhulukazi i-physics, yenze kwaba nokwenzeka ukudala izinsiza ezibonakalayo njengezibuko nama-contact lens.
Lesi sihloko sihlola indlela iso elisebenza ngayo, okwenza abantu bakwazi ukubona. Incazelo yokuthi iso lisebenza kanjani kulesi sihloko ihlobene nesihloko se- geometric optics , okuhlanganisa ukugqama kokukhanya, ukugxila, kanye nokwakheka kwezithombe zezinto ngeso. Incazelo eningiliziwe yeso nokuthi lisebenza kanjani empeleni ingaphezu kobubanzi balesi sihloko. Ukungasebenzi kahle kwamehlo, indlela izibuko nama -contact lens asebenza ngayo, kuchazwa ezihlokweni ezilandelayo.
Izingxenye Zeso
I-Cornea noma ulwelwesi lwamehlo iyi-membrane eqinile, ekhanyayo emboza ingaphambili leso. Imisebe yokukhanya engena esweni iphikiswa kakhulu yi-cornea.
Umfundi noma amabhola emehlo Impuphu iyingxenye emnyama yeso lomuntu. Impuphu imnyama, ngakho-ke imunca cishe konke ukukhanya futhi ayibonisi lutho emuva. Impuphu iyindawo lapho ukukhanya kungena khona esweni. Uma impuphu inkulu, ukukhanya kungena kakhulu esweni, futhi ngokuphambene nalokho, uma impuphu incane, ukukhanya okuncane kungena esweni.
Iris noma iris I-iris ilawula ubukhulu bomfundi. Uma indawo ezungeze iso ikhanya kakhulu, i-iris inciphisa umfundi, futhi uma indawo ifiphele, i-iris ikhulisa umfundi, okuvumela ukukhanya okwengeziwe ukuthi kungene esweni. Uma uke wabona umehluko ezimpungeni zekati emini nasebusuku, uzoqonda kalula umsebenzi we-iris.
Imisipha ye-ciliary isebenza ukushintsha ukugoba kwelensi yeso. Izinguquko ekugobeni kwelensi yeso zithinta ubude be-focal lens yeso. Uma iso libona into ekude kakhulu, imisipha ye-ciliary izophumula ukuze i-radius yokugoba kwelensi ikhule futhi ubude be-focal lens bukhuphuke. Uma iso libona into ekude kakhulu, imisipha ye-ciliary iyafinyela ukuze i-radius yokugoba kwelensi inciphe futhi ubude be-focal lens bunciphe. Ngakho-ke ngokungaqondile umsebenzi wemisipha ye-ciliary ukulawula ubude be-focal lens yeso ukuze iso likwazi ukugxila kahle esithombeni sento. Izinguquko ebude be-focal lens yeso zibizwa ngokuthi indawo yokubeka iso.
Ilensi yeso ilensi ehlanganayo, eyaziwa nangokuthi ilensi eqondile, noma ilensi enhle . Nakuba ukukhanya okuningi okungena esweni kuphenduka ku-cornea, ilensi iphinde iphenduke futhi igxilise imisebe yokukhanya ukuze isithombe sento sakheke ngqo ku-retina. Isithombe kumele sakheke ku-retina ukuze izinto zibonakale kahle. I-retina iguqula amaza okukhanya abe izimpawu zikagesi ezidluliselwa nge-optic nerve ziye ebuchosheni.
Indawo yokuhlala ephezulu kanye nephansi
Indawo yokuhlala kwamehlo ukulungiswa kobude be-focal (f) belensi yeso kuya ebangeni lento ebonwa yiso, ukuze isithombe sento sikwazi ukugxila ku-retina. Ubude be-focal belensi yeso yibanga eliphakathi kwelensi nendawo egxile kulensi (F). Izinguquko ekugobeni kwelensi zibangela ukuthi i-radius yokugoba kwelensi ishintshe ngakho-ke ubude be-focal belensi buyashintsha, njengoba kuboniswe esithombeni.
Uma iso libona into ethile iphuzu elikude, imisipha ye-ciliary iyakhululeka (iyakhululeka) okwenza ilensi yeso ibe yisicaba ukuze ubude be-rediyu yokugoba kanye nobude be-focal lens bukhule. Iphuzu elikude yibanga elide kakhulu iso elingagxila kulo, lapho iphuzu elijwayelekile elikude leso lingapheli. Lapho iso lilungisa ubude be-focal lens ukuze ligxile ezintweni ezikude noma ezintweni ezingapheli, iso indawo yokuhlala encane.
Ngakolunye uhlangothi, lapho iso libona into eduze, imisipha ye-ciliary iyaqina (iyafinyela) okwenza ilensi yeso igobe kakhulu ukuze ubude be-rediyu yokugoba kanye nobude be-focal yelensi bukhule. Ibanga lento eseduze neso iso elingagxila kulo libizwa ngokuthi eduze nendawoUmuntu ojwayelekile ucishe abe yi-25 cm ubude. Uma iso ligxile entweni eseduze (25 cm), iso liyakwazi ukwamukela indawo yonke.
Ukwakheka kwesithunzi sento
Ibanga Elikude Kakhulu Lezinto
Uma ibanga lento lingenamkhawulo, ilensi yeso iba yithafa ukuze ubude be-focal belensi bukhule, lapho ubude be-focal (f) kumele bulingane nebanga lesithombe (s'). Ibanga lesithombe yibanga eliphakathi kwelensi nendawo lapho imisebe yokukhanya ephikisiwe yeso ihlangana khona. Iphuzu lapho imisebe yokukhanya ihlangana khona ne-retina. Ngakho-ke kungaphethwa ngokuthi lapho iso libona into ebangeni elingenamkhawulo, ukugoba kwelensi yeso kuba yithafa kuze kube yilapho ubude be-focal belensi (f) bulingana nebanga eliphakathi kwelensi yeso ne-retina. Imisebe yokukhanya kumele ihlangane ne-retina ukuze ukukhanya kuguqulwe kube izimpawu zikagesi ngamaseli ezinzwa ku-retina bese kudluliselwa ebuchosheni nge-optic nerve.
Lokhu okulandelayo kuwubufakazi bezibalo bokuthi kungani uma ibanga (ama) lezinto likude kakhulu noma uma into ithathwa njengekude kakhulu, ubude be-focal lens (f) kumele bufane nebanga (ama) lesithombe. Ubudlelwano phakathi kobude be-focal (f), ibanga (ama) lezinto kanye nebanga (ama) lesithombe buvezwa nge-equation elandelayo.
1/f = 1/s + 1/s' โโ Isibalo 1
I-eyepiece ilensi ehlanganayo, ngakho-ke ubude be-focal (f) buyi-positive. Ibanga lezinto alinamkhawulo, ngakho-ke faka esikhundleni sebanga lezinto ku-equation 1 ngophawu lwe-infinity.
1/f = 1/~ + 1/s'
1/f = 0 + 1/s'
1/f = 1/s'
s' = f โโ Isibalo 2
Isibalo 2 sibonisa ukuthi kulensi ehlanganayo noma ilensi eqondile, uma ibanga lento lingenamkhawulo khona-ke ubude be-focal (f) bufana nebanga lesithombe (s').
Ibanga Lento Eliseduze Kakhulu
Kuthiwani uma into iseduze neso? Ilensi egobile ingakha izithombe ezibonakalayo nezingokoqobo. Isithombe sangempela sikhiqizwa ilensi egobile lapho ibanga lento (ama) likhulu kunobude bokugxila belensi (f). Lokhu kuxoxwe ngakho esihlokweni isithombe selensi eqondile.
Kwachazwa ngaphambilini ukuthi into eseduze kakhulu iso elivamile elingagxila kuyo kahle ingu-25 cm. Ngakho-ke, ubude bokugxila kumele bube ngaphansi kuka-25 cm. Akunakuba futhi ngu-25 cm ngoba ukube bekunjalo, isithombe besiyoba singapheli, okuyinto engacabangeki uma ubheka usayizi omncane we-pupil.
Ukubala ukulinganisa ubude be-focal (f) besistimu yelensi yeso:
1/f = 1/s + 1/s' โโ Isibalo 1
Iphuzu eliseduze leso elivamile lingu-25 cm, ngakho-ke ibanga (ama) lento eliseduze lingu-25 cm. Ibanga eliphakathi kwe-cornea neso lingaba ngu-2,5 cm. Isithombe sibonakala sicacile uma ukukhanya kuwela ku-retina, ngakho ibanga eliphakathi kwe-cornea nelensi libhekwa njengebanga (ama) lesithombe.
1/f = 1/s + 1/s'
1/f = 1/25 + 1/2,5 = 1/25 + 10/25 = 11/25
f = 25/11
f = 2,27 cm
Umehluko phakathi kwebanga lesithombe (s') kanye nebanga eliqondile (f) lingu-2,5 cm โ 2,27 cm = 0,23 cm. Ngokusekelwe emiphumeleni yokubala engenhla, kungaphethwa ngokuthi ibanga eliqondile (f) lincane kunebanga lesithombe (s'). Iphuzu eliqondile leso lingu-0,23 cm ngakwesobunxele sephuzu lesithombe noma i-retina.
Ilensi yeso iyahlangana, ngakho isithombe esakhiwe ku-retina, nakuba singokoqobo, siphendukezelwe. Ngisho noma isithombe esiku-retina siphendukezelwe, imizwa yobuchopho isenza siqonde. Lokhu kungachazwa kanjani? ๐
Imibuzo eyisibonelo mayelana nezinsimbi zamehlo ezibonakalayo
1. I-EBTANAS-SMP-01-15
Incazelo yokwakheka kwesithombe ezifweni zamehlo ezi-myopic yile...
Ingxoxo
I-Nearviewing noma i-myopia yisifo sokubona iso lapho iso lingakwazi ukubona izinto zikude ngokucacile.
Imbangela yokungaboni kahle yisimiso se-cornea-lens esigobile kakhulu (ingxenye evundlile yeso inde kakhulu) ukuze ubude bokugxila besistimu ye-cornea-lens buncishiswe, okubangela ukuthi imisebe yokukhanya evela endaweni ekude igxile phambi kwe-retina. Imisebe yokukhanya engenamkhawulo ayigxilile ku-retina ukuze amangqamuzana ezinzwa ku-retina angakwazi ukuguqula amaza okukhanya abe izimpawu zikagesi ezizodluliselwa ebuchosheni.
Impendulo efanele ingu-B.
2. I- EBTANAS-SMP-02-15
Ukwakheka kwezithunzi kubantu abane-myopia kuboniswa esithombeni esifanele...
Ingxoxo
I-Nearviewing noma i-myopia yisifo sokubona iso lapho iso lingakwazi ukubona izinto zikude ngokucacile.
Imbangela yokungaboni kahle yisimiso se-cornea-lens esigobile kakhulu (ingxenye evundlile yeso inde kakhulu) ukuze ubude bokugxila besistimu ye-cornea-lens buncishiswe, okubangela ukuthi imisebe yokukhanya evela endaweni ekude igxile phambi kwe-retina. Imisebe yokukhanya engenamkhawulo ayigxilile ku-retina ukuze amangqamuzana ezinzwa ku-retina angakwazi ukuguqula amaza okukhanya abe izimpawu zikagesi ezizodluliselwa ebuchosheni.
Impendulo efanele ngu-C.
