Characterization of a Transformation Function of a Photochromic Adaptive Filter

Simple, fast and accurate procedure is developed for measuring a Transformation Function (TF) of a Photochromic Adaptive Filter (PAF). Photochromic filters, whose spectral transmittance depends on previous and immediate radiant exposure and other environmental conditions, require special methods of spectro-photometry to determine their properties. This article describes methodology of characterizing the luminous transmittance as a function of light intensity using easy to implement method. Transformation functions of sample filters for different sources of radiation and varied light intensity are evaluated. The measuring system can also be used for fast determination of spatially and spectrally uniform light sources with UV spectral component.