Illuminance spatial distribution based total luminous flux determination for white LEDs

Here we report on the application of the well known photo-goniometric method, based on illuminance spatial distribution direct measurements, to determine the total luminous flux for high-intensity white LED sources; thus testing the CENAM primary metrology capabilities recently developed to face the increasing needs claimed by the rapidly moving solid-state lighting industrial sector in Mexico. These first results obtained at CENAM after the gonio-photometric method implementation, allowed us to determine in good accuracy the total luminous flux for a high intensity white LED source, with an estimated uncertainty of 2.86 % (k=1); still lower than the claimed by the tested LED manufacturer. We clearly identified the spectral mismatch correction factor determination and the LED junction temperature measurement and control as the dominant uncertainly sources, and will be addressed in order to improve the accuracy of the measurement system for future experiments.