scope:

The objective of this report is to publish an LED reference spectrum for luminous responsivity calibrations of V(λ)-filtered photometers. For this purpose, the illuminant LED-B3 representing white LEDs with correlated colour temperature of 4 103 K is used with its spectral data extrapolated to the full photometric wavelength range naming it "CIE reference spectrum L41". CIE reference spectrum L41 is intended to complement CIE standard illuminant A in calibrations of photometers for measuring photometric quantities of white light emitting diodes (LEDs) with reduced spectral mismatch. In addition to the tabulated data of the CIE reference spectrum L41, this report includes a quality metric for selection of white LEDs spectrally close to CIE reference spectrum L41 for use in physical LED standard sources. Information on magnitudes of spectral mismatch errors in measurements of different types of light sources is provided.