# 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.

To search for another term please use  "Back to the list" to return to the main page or the e-ILV.

For the complete set of terms and definitions CIE S 017:2020 can be purchased from the CIE Webshop. Members of a CIE National Committee or Associate National Committee have access to a 66,7 % discount on the purchase price of the standard.

# 17-21-081

luminous exitance

Mv; M

density of exiting 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 from which the luminous flux leaves

Note 1 to entry: Luminous exitance can be derived from the spectral radiant exitance distribution by

where Km is maximum luminous efficacy, Me,λ(λ) is the spectral radiant exitance at wavelength λ and V(λ) is spectral luminous efficiency.
Integral limits can be confined depending on the spectral responsivity of the detectors used as a sensor.

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

Note 3 to entry: The luminous exitance is expressed in lumen per square metre (lm·m−2).

Note 4 to entry: This entry was numbered 845-01-48 in IEC 60050-845:1987.

Note 5 to entry: This entry was numbered 17-735 in CIE S 017:2011.

Publication date: 2020-12