40 by weight as indicated above the selection of an inorganic crystalline 42 and glassy material 44 should be according to index matching that is the index of refraction n o of the inorganic crystalline 42 should be approximately equal to the index of refraction n g of the glassy material to provide an index of refraction n 2 for the light emitting composite materiel 40 by nearly index matching the inorganic crystalline 42 to the glassy material 44 scattering induced loss is nearly eliminated that is by establishing an n g that is approximately equal to n c the phosphor emission will travel at a speed within the inorganic crystalline 42 that is approximately equal to the travel speed within the glassy material 44 and thus reduce refraction or a change in the direction of the emission as a result scattering is reduced and u03b7 p increased total internal reflections 48 occur when the interface between first and second material 52 54 cannot be traversed by light as illustrated with a conventional led device 50 in fig5 this condition at the interface occurs when the refractive index of the first material 52 here the phosphor is greater than the refractive index of the second material 54 according to snell 39 s law the light cannot traverse the interface but will either refract along the interface or undergo total internal reflection total internal reflection 48 of the emission 58 continues until all of the energy in the emission is reabsorbed 60 by the phosphor thus snell 39 s law can be used to calculate a radius at which total internal reflections 48 are eliminated this radius.