Comments on “Maximum White Luminous Efficacy of Radiation Versus Color Rendering Index and Color Temperature: Exact Results and a Useful Analytic Expression”

This is a comment on a previously published paper by Hung and Tsao (J. Display Technol., vol. 9, June 2013). The reference illuminant should be a CIE Daylight illuminant, not a Planckian radiator, if the color temperature is higher than 5000 K . We find that the maximum white luminous efficacy of radiation (MWLER) along Daylight locus is higher than Hung´s results. Furthermore, we calculate the MWLER for white light allowing chromaticity difference from the Planckian or CIE Daylight locus on the CIE 1960 UV chromaticity diagram up to 0.0054.