Fluorescent lamp processing which improves performance of zinc silicate phosphor used therein

A fluorescent lamp comprising a sealed elongated light-transmitting envelope having electrodes operatively positioned therein proximate the ends thereof and enclosing a discharge-sustaining filling comprising mercury and a small charge of inert ionizable starting gas, a transparent electrically conducting coating substantially comprising tin oxide carried on the interior surface of said envelope, a thin substantially transparent coating principally comprising sub-micron-size aluminum oxide particles carried on said tin oxide coating, and finely divided phosphor means coated over said aluminum oxide, said phosphor means comprising manganese-activated zinc silicate phosphor, said lamp having been fabricated with the improved processing step which comprises:

• said aluminum oxide prior to application onto said tin-oxide-coated envelope interior surface is suspended in a liquid vehicle and a predetermined amount of finely divided antimony oxide is included in mixed suspension therewith, said vehicle-suspended oxides are applied over said tin oxide coating and the liquid vehicle then volatilized to leave a residual film of said mixed oxides, said phosphor means are then coated over said film of mixed oxides together with organic binder which must thereafter be burned out by lehring, and during the lehring processing of said coated phosphor means, substantially all of said residual antimony oxide is volatilized to contact said manganese-activated zinc silicate phosphor.