The fluorescent substance which possesses the lumen output which improves and then is made the lamp

摘要

A phosphor having a continuous protective bi-layer coating of alumina surrounding silica surrounding the phosphor particles is disclosed. The method of making a bi-layer coating on phosphor particles is also disclosed. The first layer surrounding the phosphor is silica. The second layer surrounding the phosphor is alumina. The bi-layer phosphor is useful in fluorescent lamps providing improved maintenance and brightness. The bi-layer phosphor can also be used in high color rendition lamps employing blends of phosphors.