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.

For advice on CIE Publications contact Note the CIE Helpdesk cannot assist with technical enquiries.


fluorescent radiant efficiency

quotient of the integrated value of the radiant flux of all wavelengths emitted by fluorescence (fluorescence band) and the radiant excitation power irradiating the fluorescent material for a given excitation wavelength

Note 1 to entry: The fluorescent radiant efficiency is a measure of the external radiant efficiency of the fluorescent material; the internal radiant efficiency is obtained by taking a quotient of the emitted radiation and the radiant excitation power that is absorbed by the fluorescent material.

Note 2 to entry: In this definition the excitation wavelength is considered to be monochromatic. However, in practice, the excitation radiation will have a wavelength range and distribution.

Note 3 to entry:
Fluorescence is understood to include both fluorescent and phosphorescent phenomena with time constants short enough to be ignored for the application.

Note 4 to entry: The fluorescent radiant efficiency has unit one.

Publication date: 2020-12
Copyright © CIE 2020. All Rights Reserverd.