# e-ILV

The e-ILV provides free access to all the terms and definitions contained in the international standard CIE S 017:2020 ILV: International Lighting Vocabulary, 2nd edition.

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# 17-21-060

illuminance

Ev; E

density of incident luminous flux with respect to area at a point on a real or imaginary surface
,
where Φv is luminous flux and A is the area on which the luminous flux is incident

Note 1 to entry: Illuminance can be derived from the spectral irradiance distribution by

where Km is maximum luminous efficacy, Ee,λ(λ) is the spectral irradiance at wavelength λ and V(λ) is spectral luminous efficiency.

Note 2 to entry: The corresponding radiometric quantity is "irradiance". The corresponding quantity for photons is "photon irradiance".

Note 3 to entry: The illuminance is expressed in lux (lx = lm·m−2).

Note 4 to entry: This entry was numbered 845-01-38 in IEC 60050-845:1987.

Note 5 to entry: This entry was numbered 17-550 in CIE S 017:2011.

Publication date: 2020-12