Novel Method of Total Spectral Radiant Flux Standard Realization

Modern metrology of SSL sources requires a modified approach to future realization of reference standards. This is caused by the fact that traditional broad band and omnidirectional light sources used are being replaced by high intensity sources with a specific directional light intensity distribution. At the same time the importance of LED lighting quality assurance is increasing as this new type of lighting is currently replacing traditional light sources in many applications. The specifics of an integrating sphere-spectroradiometer measurement system require the calibration with the use of a reference standard with known Spectral Radiant Flux Distribution, Luminous flux as well as the Luminous Intensity Distribution (LID) to compensate for the sphere system nonuniform reflectance properties. This way the accuracy of the sphere system calibration will allow to measure various types of LED products in conformance with the EN 13032-4:2015, LED lamps, modules and luminaires modules, lamps regardless of their spatial distribution properties. This paper will cover basic concepts and details of a novel method of Total Spectral Radiant Flux (TSRF) realization and description of a TSRF standard facility developed for the Russian National Metrology Institute - VNIIOFI, Moscow. The method (and the developed facility) is based on a goniospectroradiometer system traceable to a standard Black Body and allowing the calibration of a light source in terms of TSRF and additionally providing LID data of the source.