Patent ID: 6335083
Filing Date: 2002-01-01
Classification: C03C,C04B,Y10S,Y10T

Abstract:
Transparent solid, fused microspheres comprising(a) at least one oxide selected from the group consisting of alumina, zirconia, and mixtures thereof, and optionally silica in a total content of at least about 70% by weight, based on the total weight of the solid, fused microspheres, wherein: (i) there is no greater than about 35% by weight silica; (ii) the total content of any alumina present and any zirconia present is within a range of about 45% by weight to about 95% by weight; and (b) zinc oxide, one or more alkaline earth metal oxide, or combinations thereof, in a total amount of about 0.1% by weight to about 30% by weight; and further wherein the microspheres have an index of refraction of at least about 1.6 and are useful as lens elements.