Yadda ake rage hayaniyar photodetectors

Yadda ake rage hayaniyar photodetectors

Hayaniyar na'urar ganowa ta ƙunshi: amo na yanzu, amo mai zafi, ƙarar harbi, 1/f amo da amo mai faɗi, da dai sauransu. Wannan rarrabuwar ba ta da ƙarfi kawai. A wannan lokacin, za mu gabatar da ƙarin cikakkun bayanai game da halayen amo da rarrabuwa don taimakawa kowa da kowa ya fahimci tasirin nau'ikan amo daban-daban akan siginar fitarwa na masu gano hoto. Ta hanyar fahimtar tushen amo ne kawai za mu iya ragewa da inganta hayaniyar masu binciken hoto, ta haka inganta siginar sigina na tsarin.

Hayaniyar harbi wani canji ne na bazuwar da ke haifar da tsayayyen yanayin masu ɗaukar kaya. Musamman a cikin tasirin photoelectric, lokacin da photons ya buge abubuwan da ke ɗaukar hotuna don samar da electrons, haɓakar waɗannan electrons ba zato ba tsammani kuma sun dace da rarraba Poisson. Siffofin sifofi na karar harbin lebur ne kuma masu zaman kansu daga girman mitar, don haka kuma ana kiranta farin amo. Bayanin lissafi: Tushen ma'anar murabba'i (RMS) ƙimar amo ana iya bayyana shi kamar:

Tsakanin su:

e: Cajin lantarki (kimanin 1.6 × 10-19 coulombs)

Idark: Dark current

Δf: Bandwidth

Hayaniyar harbi tana daidai da girman na yanzu kuma tana da tsayi a kowane mitoci. A cikin dabarar, Idark yana wakiltar duhu halin yanzu na photodiode. Wato, idan babu haske, photodiode yana da hayaniyar duhu maras so. A matsayin hayaniyar da ke cikin gaban ƙarshen mai gano hoto, mafi girman duhun halin yanzu, mafi girman hayaniyar na'urar. Dark current kuma yana shafar wutar lantarki mai aiki da son zuciya na photodiode, wato, girman ƙarfin aiki na son zuciya, mafi girman duhun halin yanzu. Koyaya, ƙarfin ƙarfin aiki na son zuciya shima yana shafar ƙarfin junction na photodetector, ta haka yana rinjayar saurin da bandwidth na mai binciken hoto. Bugu da ƙari, mafi girman ƙarfin wutar lantarki, mafi girma da sauri da bandwidth. Saboda haka, dangane da karar harbi, duhu halin yanzu da aikin bandwidth na photodiodes, ya kamata a aiwatar da ƙira mai ma'ana bisa ga ainihin bukatun aikin.

2. 1/f Hayaniyar Flicker

1/f amo, wanda kuma aka sani da flicker amo, yafi faruwa a cikin ƙananan mitoci kuma yana da alaƙa da abubuwa kamar lahani na abu ko tsabtar ƙasa. Daga zane mai ban mamaki, ana iya ganin cewa ƙarfin siginar ikonsa ya fi ƙanƙanta sosai a cikin kewayon maɗaukaki fiye da na ƙaramar mitar, kuma a kowane sau 100 yana ƙaruwa a mitar, sautin ƙararrakin na gani yana raguwa da sau 10. Ƙaƙƙarfan ƙarfin juzu'i na 1/f amo ya yi daidai da mitar, wato:

Tsakanin su:

SI(f): Ƙarfin amo mai yawa

I: Yanzu

f: Yawanci

1/f amo yana da mahimmanci a cikin ƙananan mitoci kuma yana raunana yayin da mitar ke ƙaruwa. Wannan halayyar ta sa ta zama babban tushen tsangwama a cikin ƙananan aikace-aikace. 1/f amo da faɗaɗa amo galibi suna fitowa ne daga ƙarar ƙarfin lantarki na amplifier mai aiki a cikin na'urar gano hoto. Akwai wasu hanyoyin hayaniya da yawa waɗanda ke shafar hayaniyar na'urorin gano hoto, kamar ƙarar wutar lantarki na na'urori masu aiki, amo na yanzu, da hayaniyar zafi na cibiyar sadarwar juriya a cikin ribar da'irar amplifier mai aiki.

3. Voltage da amo na yanzu na amplifier mai aiki: Ana nuna ƙarfin lantarki da ƙarancin gani a cikin adadi mai zuwa:

A cikin da'irori na amplifier masu aiki, an raba hayaniyar yanzu zuwa amo na yanzu da jujjuya amo na yanzu. Hayaniyar in-lokaci na yanzu i+ yana gudana ta hanyar juriya na ciki Rs, yana haifar da hayaniya daidai gwargwado u1= i +* Rs. I- Inverting current amo yana gudana ta hanyar riba daidai resistor R don samar da daidaitaccen hayaniyar ƙarfin lantarki u2= I-* R. Don haka lokacin da RS na wutar lantarki ya yi girma, ƙarar wutar lantarki da ta canza daga hayaniyar yanzu tana da girma sosai. Sabili da haka, don haɓaka don ingantacciyar amo, ƙarar wutar lantarki (ciki har da juriya na ciki) kuma shine mabuɗin jagora don ingantawa. Ƙaƙƙarfan ƙaƙƙarfan amo na yanzu baya canzawa tare da bambancin mita ko dai. Saboda haka, bayan an ƙara haɓaka shi ta hanyar da'ira, kamar duhu halin yanzu na photodiode, gabaɗaya yana haifar da karar harbin na'urar gano hoto.

4. The thermal amo na juriya cibiyar sadarwa domin riba (amplification factor) na aiki amplifier kewaye za a iya lissafta ta amfani da wadannan dabara:

Tsakanin su:

k: Boltzmann akai-akai (1.38 × 10-23J/K)

T: Cikakken Zazzabi (K)

R: Juriya (ohms) amo mai zafi yana da alaƙa da zafin jiki da ƙimar juriya, kuma bakan sa lebur ne. Ana iya gani daga dabarar cewa mafi girman ƙimar juriya na riba, mafi girma amo na thermal. Girman bandwidth, mafi girman hayaniyar zafi kuma zai kasance. Sabili da haka, don tabbatar da cewa ƙimar juriya da ƙimar bandwidth sun haɗu da buƙatun riba da buƙatun bandwidth, kuma a ƙarshe kuma suna buƙatar ƙaramar ƙararrawa ko babban siginar sigina zuwa amo, zaɓin masu tsayayyar riba yana buƙatar yin la'akari da hankali da kimantawa bisa ainihin buƙatun aikin don cimma madaidaicin sigina-zuwa amo rabo na tsarin.

Takaitawa

Fasahar inganta surutu tana taka muhimmiyar rawa wajen haɓaka aikin na'urar gano hoto da na'urorin lantarki. Babban madaidaici yana nufin ƙaramar amo. Kamar yadda fasaha ke buƙatar daidaito mafi girma, buƙatun don amo, sigina-zuwa-amo rabo, da makamancin ƙarfin amo na photodetectors suma suna ƙara girma.