INTENSITY OF EMITTED LIGHT FROM POWDER PHOSPHORS - THE EFFECTS OF LIGHT-ABSORPTION AND SCATTERING IN THE POWDER MATRIX

The intensity of light emitted by a luminescent powder is treated in t erms of the equations of Kubelka and Munk. The analysis given is appli cable to uniform powder layers, and the assumption is made that the li ght originates with constant intensity at all points throughout the la yer. This is a reasonable approximation to the behaviour of phosphor p reparations used in a number of electroluminescent and radioluminescen t display devices, and also describes well the emission of light from powder samples exhibiting thermoluminescence. The calculated emission intensity shows a complex dependence on the absorption and scattering coefficients of the powder and on the layer thickness; expressions for this dependence are discussed.