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.