D5 : Evaluation of a complementary general V(λ) mismatch index

This report is associated with the CIE Division Reportership DR 2-89 Definition of a complementary general V(λ) mismatch index, with the terms of reference “To demonstrate the needs for a complementary general V(λ) mismatch index, and propose a definition to fulfil these needs, especially for the discussion in relation to the revision of ISO/CIE 19476:2014(E) and CIE S 025/E:2015.” The report presents parts of a detailed analysis of the issues related to a possible compliment to ’ଵ the general () mismatch index as presented in recent papers (Krüger et al., 2022b, 2021).

It is shown that the issues related to the reliability of the general () mismatch index is not strongly related to the specific definition of the index but rather to the spectral distribution of the device under test (DUT) and the spectral distribution of the calibration lamp. This is such that replacing CIE illuminant A with an LED source similar to L41 as the calibration source will decrease the expected error, measured by the spectral mismatch correction factor.

This is shown by an investigation of the statistical relation between the various indices and the expected deviation in results from various combination of instruments, calibration sources and DUT spectral distributions. The final conclusion of the authors is that the various changes proposed does not produce significantly different results from the status quo, so there is no need to change the current definition of the general () mismatch index.

This report is based on the work detailed in publications (Krüger et al., 2022b, 2021), which was funded as part of the Joint Research Project within the European Metrology Research Programme EMPIR “Revision and extension of standards for test methods for LED lamps, luminaires and modules” (RevStdLED 19NRM02), the project has had active participation from countries Germany, Finland, Spain, Portugal, France, Turkey, Denmark, Ukraine and South Africa.