| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a bulb which can surely prevent a tarnish of a filament, devitrification of a bulb and weakening of the filament or the like by giving enough antioxidation measures to a luminous filament. SOLUTION: A manufacturing method of a (wedge base) bulb 10 is provided at least with a pinch sealed process P3 for forming a flat base part 4 without a base by heat sealing an opening part 501 of a bulb 5 with an luminous filament 3 inserted which is suspended and fixed on the upper end of lead wires 1a, 1b arrayed in parallel, pressure-reducing processes S2 and S3, after this pinch sealed process P3, lowering internal bulb pressure by vacuum suction means or the like, a gas exchange process S4, after this pressure-reducing process, exchanging air inside of the bulb with nitrogen gas or the like.
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