| 摘要 |
PROBLEM TO BE SOLVED: To improve lighting reliability, by maintaining inherent fuse action by a specific wire, and embedding one end of the wire into a bottleneck part. SOLUTION: A bayonet-type base part 16 is closed by the bottleneck part 5, by enclosing an enclosing gas composed of an inert gas and a halogen- containing additive, a light-emitting body 6 having two end parts, and a luminous filament part 8 into a quart glass bulb 2, wherein a round-type head part 3 having an exhaust tube 4 in the center. A lead system for supplying electricity to the light-emitting body 6 is connected to a closed foil 20 embedded into the bottleneck part 5, and contains inner leads 19, wherein part of a length is embedded into the bottleneck part 5. At least one of these inner leads 19 is made of a wire having 130μm or more and has inherent fuse action. When two mm or more of the wire length is embedded into the bottleneck part 5 and an arc is generated between the leads by an interval (d) between the leads and applied voltage V; electric field strength V/d acting there is made to have 100V/cm or more. |
