Gas-filled incandescent lamp with integral fuse assembly

Abstract

Protection against potentially destructive arcs which may occur within a gas-filled incandescent lamp when the energized filament fails is achieved by partly embedding separate inner and outer lead-in conductors in an hermetic seal that is formed on one end of the lamp envelope and electrically connecting the conductors by a short uncoiled fuse element that is located within the confines of the envelope and has both of its ends embedded in the seal. In the case of halogen-cycle type lamps that have long useful design lives (in the order of 2000 hours) and press-sealed envelopes, the fuse element comprises a tungsten wire that has a diameter which is more than 10% (and up to about 20%) larger than the diameter of the filament wire and has its ends welded to a pair of molybdenum foil conductors that are embedded in the press seal and connect the fuse wire to the inner and outer lead-in conductors. Reliable arc-suppression is thus achieved in a practical and inexpensive manner with rugged sealed-in components that are readily welded together and made integral parts of the finished lamps.

Dependencies are inferred from the claim text.