| 摘要 |
PROBLEM TO BE SOLVED: To provide a fluorescent lamp covering device 14 in which light emitting efficiency can be improved and lamp lifetime can be prolonged even in low-temperature environments, and in which sharing of the fixture main body is possible. SOLUTION: An arc tube 22 of the fluorescent lamp 13 is covered by an inner tube 31, the inner tube 31 is covered by an outer tube 32, and the light emitting efficiency is improved in the low-temperature environments. The outer tube 32 is shorter than the length of the inner tube 31, and an exposed part 33 in which the inner tube 31 is exposed is formed at the end part of the inner tube 31 corresponding to the end part filament part 26 of the fluorescent lamp 13. By forming the exposed part 33, an excessive temperature rise of the filament part 26 of the fluorescent lamp 13 is suppressed and the lamp lifetime is prolonged. Only the inner tube 31 is positioned in the end part of the fluorescent lamp13, and the fixture main body can be shared regardless of use or non-use of the outer tube 32. COPYRIGHT: (C)2005,JPO&NCIPI
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