luminosity factor

...The luminosity factor is a measure of the radiant energy (unit: W) transmitted per unit time. Since the sensitivity of the eye varies greatly depending on the wavelength of light, the sensitivity is expressed as the reciprocal of the energy of monochromatic light that produces a certain sense of brightness, and is called the luminosity factor. For measuring luminous flux, the luminosity factor of the standard observer determined by the International Commission on Illumination in 1926 is used. The wavelength range in which luminosity exists is approximately 400 to 700 nm, with the maximum sensitivity at a wavelength of 555 nm (photopic vision). ...

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Source | Heibonsha World Encyclopedia 2nd Edition | Information

…単位時間に伝搬される放射エネルギー(単位，W)を視感度で測ったもの。目の感度は光の波長によって大きく変わるので，感度を，一定の明るさの感覚を生ずる単色光のエネルギーの逆数で表し，これを視感度luminosity factorと呼ぶが，光束の測定では，1926年に国際照明委員会で決定された標準観測者のもつ視感度を用いる。視感度の存在する波長範囲はほぼ400～700nmで，感度の最大は波長555nmのところ(明所視)にある。…

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