Electric lamp having an outer bulb

摘要

Electric lamp (1) includes a discharge vessel (3) sealed at both ends by fuse seals (2) and enclosed by a cylindrical outer bulb (8). Each fuse seal surrounds an elongated molybdenum foil (4) and has a flange (6) near its tubular opening (5). Both ends of the outer bulb have a tapered neck (9) which is formed at halfway level of the foil and ends at the flange to which it is sealed. The total length ratio between outer bulb (LAKO) and inner bulb's interior length (LEG) is between 1.5 and 3 while the maximum diameter ratio between outer (DAKO) and inner (DEG) bulbs is between 1.2 and 2.