Maximum luminous efficiency of optical module

In the photopic region, luminous efficacy peaks at 683 lumens per watt at 555 nm. In fact, the lumen is defined in terms of the power at 555 nm (frequency of 540 × 1012 Hz). Luminous efficacy is defined as the luminous flux produced per unit of power, usually electrical power, measured in lumen per watt (lm/W). It is explained how the overall efficacy of a lighting installation is often lower than that of the light source itself due to factors like light absorption in. Luminous efficacy is a measure of how efficiently a light source produces visible light. Depending on context, the power can be either the radiant flux of the source's output, or it can. The relative spectral responsivity of the human visual system was first defined by the Commission Internationale de l'Éclairage (CIE, the International Commission on Illumination) in 1924. The response of the eye as a function of frequency is called the luminous efficacy of the eye. It has been tabulated for both the light-adapted (photopic) case and the dark-adapted (scotopic) case. Source: Table 6-1 of. [PDF]