IEVref:845-21-092ID:
Language:enStatus: Standard
Term: maximum luminous efficacy, <for a specified photometric condition>
Synonym1:
Synonym2:
Synonym3:
Symbol: Km, <for photopic vision> <pour la vision photopique>
Km, <for scotopic vision> <pour la vision scotopique>
Km,mes;m, <for mesopic vision> <pour la vision mésopique>
Km,10, <for the CIE 10° photopic photometric observer> <pour l'observateur photométrique photopique 10° CIE>
Km,M, <for the CIE 1988 modified 2° spectral luminous efficiency function for photopic vision> <pour la fonction d'efficacité lumineuse relative spectrale de 2° pour vision photopique (CIE 1988 modifiée)>
Definition: maximum value of spectral luminous efficacy for a specified photometric condition

Note 1 to entry: The photometric condition should be specified (e.g. photopic, scotopic, mesopic). If it is not specified, photopic vision is assumed and the symbol Km is used. For other photometric conditions, the respective symbol for identification shall be used.

Note 2 to entry: The value of maximum luminous efficacy for photopic vision is calculated by

K m = 683 V( λ cd ) cdsr W 1 683 lm W 1 MathType@MTEF@5@5@+= feaagKart1ev2aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbbjxAHX garuavP1wzZbItLDhis9wBH5garmWu51MyVXgaruWqVvNCPvMCG4uz 3bqee0evGueE0jxyaibaieYdi9WrpeeC0lXdh9vqqj=hEeea0xXdbb a9frFj0=OqFfea0dXdd9vqaq=JfrVkFHe9pgea0dXdar=Jb9hs0dXd bPYxe9vr0=vr0=vqpWqaaeaaciWacmGadaGadeaaeaGaauaaaOqaai aadUeadaWgaaWcbaGaaeyBaaqabaGccqGH9aqpdaWcaaqaaiaabAda caqG4aGaae4maaqaaiaadAfacaqGOaGaeq4UdW2aaSbaaSqaaiaabo gacaqGKbaabeaakiaabMcaaaGaae4yaiaabsgacqGHflY1caqGZbGa aeOCaiabgwSixlaabEfadaahaaWcbeqaaiabgkHiTiaabgdaaaGcqa aaaaaaaaWdbiabgIKi7kaaiAdacaaI4aGaaG4maiaabccacaqGSbGa aeyBa8aacqGHflY1peGaae4va8aadaahaaWcbeqaa8qacqGHsislca aIXaaaaaaa@5900@

where V(λ) is the spectral luminous efficiency for photopic vision and λcd is the wavelength in air corresponding to the frequency 540 × 1012 Hz specified in the definition of the SI unit candela.

Note 3 to entry: The maximum luminous efficacy is expressed in lumen per watt (lm·W−1).


Publication date:2020-12
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