| 摘要 |
PROBLEM TO BE SOLVED: To provide an incandescent lamp which can be converted to a compact point light source by further multiplexing the form of a coil-shaped filament while having little gas loss even if converted to the point light source, and of which miniaturization, and improvement of luminescent efficiency and life characteristics can be attained as a result, and to provide a lighting device using the bulb. SOLUTION: The incandescent lamp L includes a translucent airtight vessel 1 having the maximum diameter of 25-40 mm, a pair of lead wires 4 brought into the translucent airtight vessel 1, the coil-shaped filament 6 the end part of which is connected to the lead wires 4, in which a tungsten wire having a wire diameter of 0.04-0.06 mm is trebly wound and the minimum interval of turns in a single coil-shaped part is 0.10-0.12 mm, the minimum interval of turns in a double coil-shaped part is 0.45-0.55 mm, and the minimum interval of turns in a triple coil-shaped part is 1.2-1.5 mm, an inactive gas filled in the translucent airtight vessel 1, and is lighted by power of 20-100 W. This bulb L is used in the lighting device. COPYRIGHT: (C)2008,JPO&INPIT
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