Protection against air absorption by incandescent lamps - uses resealing of lead wires in bulb pinch after lamp finished prodn.

摘要

The two passages in the bulb, together with the pinch, serving for the insulation of leads to the filament, are resealed after the lamp finished production effectively against external air absorption which would reduce the lamp service life by reacting with the filament metal. The resealing is carried out by application of a protective film by spraying, or dipping either to the entire bulb or to the pinch only, including the cap. part. Alternatively a gas-tight protective cap may be applied.