| 摘要 |
PROBLEM TO BE SOLVED: To improve a service life of a lamp. SOLUTION: An improved support 42 is provided to axially mount a lamp filament 14 in a lamp sleeve. The support 42 shown in figure, is a spiral coil coming in contact with the filament 14, including a central part of a small diameter. The coil is expanded to a larger diameter at both sides of a filament contact part to come into contact with an inner wall of a quartz sleeve for accommodating the filament 14. The support 42 has an H-shape in a side view. The lamp filament 14 is provided with expansion compensating parts 74 at both sides of the central part 72. Filament wires of the expansion compensating parts 74 are respectively wound to be a coil having a diameter larger than the coil of the central part 72, and having wide clearance among winding wires. The expansion compensating parts 74 are preferably compressible to absorb the thermal expansion of the filament 14 during the operation, and the filament 14 can be prevented from being short-circuited over the adjacent winding wire.
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