Spectral power distribution of light sources: New optimisation criterion

Abstract

A new criterion for spectral power distribution (SPD) optimisation is proposed; this is evaluated numerically with a spectral utilisation factor (SUF). SUF is calculable on the basis of relative SPD and takes into account the luminous efficiency of (visible) radiation as well as the colour discrimination ability of the light source. The theoretical optimal light source is obtainable as a trichromatic line SPD of wavelengths 440-530-615 nm. The spectral areas of trichromatic SPD lines to optimise both SUF and colour rendering index (CRI) parameters have also been determined as 440-450 nm for blue, 530-540 nm for green and 610 nm for red lines at a spectral line (band) width of about 20-30 nm. Depending on correlated colour temperature and achromaticity requirements, various radiant intensity ratios of line (band) SPDS should be investigated for both the above criteria. The conclusions of the paper can be applied to improve the performance of practical light sources.