Luminous flux
Raws li tau hais ua ntej, thaum piav txog "lub teeb lub zog tawm los ntawm qhov pom lub teeb pom kev hauv ib lub sijhawm", nws tsis tsim nyog siv tsuas yog "lub zog" los ntsuas, thiab cov lus teb spectral ntawm tib neeg lub qhov muag rau lub teeb ntawm qhov sib txawv wavelengths yuav tsum tau qhia. . Kev taw qhia ntawm "luminous flux" tsuas yog daws qhov teeb meem no. Lub International Commission on Illumination (CIE) tau xaiv 555nm, lub wavelength rhiab tshaj plaws ntawm tib neeg lub qhov muag nyob rau hauv lub zeem muag photopic, raws li kev siv wavelength rau kev hloov ntawm "lub zog" rau "luminous flux", thiab tau teev tseg tias 555nm wavelength monochromatic teeb nrog lub teeb pom kev zoo. Lub zog ntawm 1W sib haum mus rau lub luminous flux ntawm 683 lumens. Lumen yog chav tsev ntawm luminous flux, thiab cov lus Askiv luv luv yog lumen lossis lm. Raws li yog vim li cas nws yog "683", nws muaj feem xyuam rau cov keeb kwm ntawm kev piav qhia txog teeb pom kev zoo nrog tswm ciab nyob rau hauv thaum ntxov hnub, uas tsis tau qhia ntawm no.
Rau lub luminous flux ntawm lwm lub wavelengths ntawm lub teeb, qhov sib thooj luminous flux ntawm 555nm yog multiplied los ntawm photopic spectral efficiency. Lub luminous flux ntawm ib tug dav-spectrum teeb qhov chaw kuj yuav tsum tau xav txog qhov spectral tis ntawm lub teeb qhov chaw nws tus kheej. CIE kuj txhais cov luminous flux nyob rau hauv scotopic vision, tab sis nws tsis yog feem ntau siv.
