The light color in prediction of spectral mismatch correction factor of class A photometers

Fryc Irena – Bialystok University of Technology, Poland
In metrology of light sources parameters, measurements of light intensity are carried out with portable photometers called luxmeters. The state of the art photometric laboratories for purpose of any lamp intensity measurements usually use class A luxmeters.
When measuring light intensity produced by light source which spectrally differs from luxmeter calibration source, the measurement result is having some error. In order to eliminate this type of error, the luxmeters used in laboratories, should be equipped with a calibration certificate containing information on their spectral mismatch correction factor (SMCF) for given lamps. This is very inconvenient because to achieve measurement with high fidelity luxmeter must be calibrated for each lamp under measurement. For this reason will be convinient to have method base on it will be possible to predict luxmeter SMCF value for given lamp based on data for similar type of lamps – for example predict SMCF value based on lamp CCT value.
The paper will analyze the effect of color temperature emitted by typical LEDs and standard FL lamps on SMCF value of class A luxmeters (set of them). To comparison of luxmeter’s SMCF values the black body radiation, described by Planck equation, will be taken under considerations also.