Yuav piav qhia txog cov yam ntxwv tseem ceeb ntawm LEDs li cas?
Raws li cov khoom siv electroluminescent PN junction, cov yam ntxwv ntawm LED tuaj yeem piav qhia los ntawm cov hluav taws xob tsis zoo ntawm PN hlws ris thiab cov khoom siv kho qhov muag raws li lub teeb pom kev zoo.
Cov yam ntxwv ntawm volt-ampere yog qhov tseem ceeb los piav qhia txog PN junction ntaus ntawv. Nws yog ib qho tseem ceeb qhia txog PN junction kev ua tau zoo thiab qhov zoo thiab qhov tsis zoo ntawm PN junction fabrication txheej txheem. Lub npe hu ua volt-ampere yam ntxwv yog tus yam ntxwv uas tam sim no ntws los ntawm PN kev sib tshuam hloov nrog qhov voltage, uas tuaj yeem ua kom pom tseeb ntawm oscilloscope. Ib qho ua tiav volt-ampere nkhaus suav nrog rau pem hauv ntej thiab rov qab cov yam ntxwv. Feem ntau, qhov rov qab tus yam ntxwv nkhaus hloov siab, thiab thaum qhov hluav taws xob ntau tshaj qhov pib, qhov tam sim no yuav nce exponentially. Feem ntau, peb qhov tsis sib xws ntawm qhov rov qab tawg voltage, rov qab tam sim no thiab rau pem hauv ntej voltage tuaj yeem siv los piav qhia txog volt-ampere yam ntxwv nkhaus.
Lub pem hauv ntej voltage VF hais txog qhov hluav taws xob poob thoob plaws hauv lub cuab yeej nyob rau hauv qhov ntsuas rau pem hauv ntej tam sim no, uas tsis yog tsuas yog cuam tshuam rau qhov txwv tsis pub band dav ntawm cov khoom, tab sis kuj txheeb xyuas qhov tsis kam thiab ohmic tiv thaiv ntawm PN hlws ris. Qhov loj ntawm VF qhia txog qhov zoo thiab qhov tsis zoo ntawm electrode fabrication rau qee yam. txheeb ze rau pem hauv ntej tam sim no ntawm 20 mA, VF tus nqi ntawm liab thiab daj LEDs yog hais txog 2 volts, thaum lub VF tus nqi ntawm GaN-raws li ntsuab LED li feem ntau yog ntau tshaj 3 volts. Qhov rov qab xau tam sim no IR yog hais txog tus nqi rov qab tam sim no ntws los ntawm lub cuab yeej nyob rau hauv ib qho rov qab voltage, thiab tus nqi ntawm tus nqi no yog rhiab heev rau qhov zoo ntawm lub cuab yeej. Feem ntau ntawm qhov rov qab qhov hluav taws xob ntawm 5 volts, qhov rov qab xau tam sim no yuav tsum tsis txhob siab dua 10 microamps, thiab qhov loj heev IR qhia tias cov yam ntxwv tsis zoo. Qhov rov qab tawg qhov hluav taws xob txhais tau hais tias thaum qhov hluav taws xob thim rov qab ntau dua ib qho nqi, qhov rov qab ntws tawm tam sim no yuav nce siab, uas qhia txog cov yam ntxwv ntawm qhov rov qab tiv thaiv hluav taws xob ntawm lub cuab yeej. Rau ib qho cuab yeej tshwj xeeb, tus qauv ntawm cov dej xau tam sim no txawv. Nyob rau hauv cov ntaub ntawv nruj dua, qhov rov qab xau tam sim no yuav tsum tsis pub ntau tshaj 10 microamps nyob rau hauv qhov ntsuas qhov ntsuas.
Ntxiv nrog rau cov yam ntxwv ntawm hluav taws xob, cov khoom siv kho qhov muag kuj tseem yuav tsum tau piav qhia txog kev ua haujlwm ntawm cov khoom siv LED, ntawm qhov tseem ceeb tshaj plaws yog lub ncov wavelength thiab lub teeb siv ntawm lub cuab yeej. Lub teeb pom kev yog nyob rau hauv qeb ntawm electromagnetic nthwv dej, thiab wavelengths feem ntau siv tau los qhia qhov uas tib neeg lub qhov muag pom tau. Lub zog radiant ntawm pom lub teeb, feem ntau lub wavelength ntau ntawm pom lub teeb nyob nruab nrab ntawm 380nm thiab 760nm. Qhov ntev lub wavelength, qhov qis dua qhov sib thooj photon zog, thiab redder xim ntawm lub teeb. Thaum lub wavelength ntawm photon ua luv, lub teeb yuav maj mam hloov los ntawm liab tig daj, ces ntsuab tig xiav, kom txog thaum nws tig liab doog. Rau ib qho khoom siv LED, lub teeb tawm los ntawm nws yuav nthuav dav ntawm lub ncov λP, thiab nws lub wavelength ib nrab-dav feem ntau yog 10-30nm. Qhov me me ntawm ib nrab-dav, cov khoom siv ntawm cov khoom siv LED ntau dua, qhov kev ua tau zoo dua qub, thiab ua tiav cov siv lead ua ntau dua. Kev sib deev kuj zoo dua. Lub teeb siv zog yog lwm qhov tseem ceeb los ntsuas qhov zoo ntawm LED kev ua tau zoo, feem ntau yog sawv cev los ntawm tsab ntawv Iv. Lub ntsiab lus ntawm lub teeb siv yog tias lub teeb nyob rau hauv ib qho kev taw qhia emits 1 lumen ntawm lub teeb nyob rau hauv ib chav tsev lub kaum ntse ntse li 1 candela, thiab nws chav tsev yog qhia nyob rau hauv candela (cd). Nws txoj kev sib raug zoo tuaj yeem sawv cev los ntawm cov qauv (6-1):
Iv{0}}dφ/dΩ (6-1)
Hauv cov qauv, chav tsev ntawm φ yog lumens, chav tsev ntawm Iv yog cd, thiab dΩ yog chav tsev khoom lub kaum ntse ntse, thiab chav tsev yog degree. Lub teeb ci ib txwm siv ntawm lub teeb ci ultra-ci LED feem ntau yog nyob nruab nrab ntawm 30-120mcd. Tom qab tau ntim rau hauv ib lub cuab yeej, nws qhov kev siv lub teeb ib txwm yog ntau dua 1cd.
Luminous flux yog lub hom phiaj ntau dua rau kev txiav txim siab qhov ua tau zoo ntawm LEDs. Nws sawv cev qhov loj ntawm lub teeb lub zog tawm los ntawm lub cev electroluminescent ib lub sij hawm, thiab chav tsev yog lumens (lm). Feem ntau, luminous kev ua tau zoo ntawm cov roj teeb thiab cov teeb fluorescent yog 15lm / w thiab 60lm / w feem. Lub zog ntawm lub teeb ntau dua, qhov ntau dua qhov luminous flux. Rau cov khoom siv LED ua haujlwm siab, qhov ua tau zoo ntawm luminous yog 20lm / w, thiab qib kuaj kuj nce mus txog 100lm / w. Txhawm rau ua kom cov khoom siv LED siv rau lub teeb pom kev zoo dua, qhov ua tau zoo ntawm cov khoom siv LED yuav tsum tau txhim kho ntxiv. Nws kwv yees tias tom qab 10 xyoo, qhov ua tau zoo ntawm LEDs tuaj yeem ncav cuag 200lm / w. Nyob rau lub sijhawm ntawd, noob neej yuav hloov mus rau lub sijhawm tshiab uas cov teeb pom kev hauv lub xeev tau hloov pauv cov teeb pom kev zoo ib txwm muaj.
