Involvement of scattered UV light in the generation of photoluminescence in powdered phosphor screens

Abstract

In powdered phosphor screens, a large fraction of incident UV light is reflected from the surface of individual particles, with the remainder penetrating the phosphor surface to generate photoluminescence. The reflected UV photons entering the screen are randomly scattered throughout the particulate structure, resulting in photoluminescence down to, for example, 10 layers deep from the surface. An optimum number of layers within a screen for luminance in reflection and transmission modes can be calculated after determination of the absorption and scattering coefficients per layer in a practical phosphor screen. Good agreement has been obtained between the calculated and experimental results.