Simplified Method to Determine the Spectral Mismatch Correction of Commercial Illuminance Meters

Abstract

Photometric quantities accuracy measured with illuminance meters is determined by the value of the spectral mismatch correction factor (F(St)), which is defined as a function of spectral power distribution of light sources, besides relative spectral responsivity of the illuminance meter used. Then appropriate determination of F factor is limited to suitably equipped laboratories.

In this work a simplified method to directly determine the illuminance responsivity to light sources other than illuminant A of commercial illuminance meters, whereby knowledge of the relative spectral responsivity of the illuminance meter to be calibrated is not necessary, is presented. The method has been proved to be useful for illuminance meters with different degrees of spectral mismatch from V(λ) function and to different spectral power distributions.