Abstract: The coiled-coil filament of a tubular incandescent lamp is held in suspended longitudinally-extending position within the envelope by lead-in conductors and a single support wire that is anchored in one of the envelope seals and has a hook portion that is coupled to one of the secondary turns of the filament. The free end of the filament-support member is formed into a single loop that nestingly engages the arcuate wall of the envelope and thus holds the support member and filament in the desired position during the sealing-in operation and within the finished lamp. The unique shape of the support member simplifies its manufacture and its subsequent assembly with the coiled filament and envelope.

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.

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 entirely within the confines of the envelope. In the case of a halogen-cycle type lamp having a press-sealed envelope, the fuse element comprises a tungsten wire which is preferably from about 1% to 10% larger in diameter than the filament wire and is fastened to the inner lead-in conductor at a point located inside the envelope, and to the outer lead-in conductor at a point which is located within the press seal. Reliable arc-suppression is thus achieved in a practical inexpensive manner with rugged components that are readily made integral parts of the finished lamp.

Abstract: The useful life of high-efficiency type bromine-tungsten cycle incandescent lamps, such as those used in TV-studio and theater lighting applications, is enhanced by dosing the lamps with a carefully controlled quantity of mercuric bromide (HgBr.sub.2) which dissociates when the filament of the finished lamp is energized and provides a predetermined amount of Br.sub.2 within the envelope during lamp operation. The quantity of HgBr.sub.2 dosed into the envelope is adjusted according to the design life and initial efficiency parameters of the specific lamp type so as to provide a concentration of Br.sub.2 within the envelope which is correlated with such parameters and prevents blackening of the envelope and premature failure of the filament at the particular "life-efficiency level" of operation for which the lamp is designed. For a 1000 watt 120 volt tubular incandescent lamp (DXW type) having a design life of 150 hours and an efficiency of 28 LPW, the HgBr.sub.2 dosage is such that it provides from about 2.