| 摘要 |
PROBLEM TO BE SOLVED: To improve the reflection efficiency of ultraviolet rays and improve the utilization of a phosphor by containing a blend of prescribed weights ofγ-alumina anα-alumina in a barrier layer. SOLUTION: An ultraviolet ray reflection barrier layer 14 having a phosphor layer 16 on the inner surface is provided on the inner surface of the envelop 12 of a fluorescent lamp 10. Namely, the layer 14 is arranged between the envelop 12 and the layer 16. This layer 14 contains a blend ofγ-alumina particle andα-alumina particle, or is formed of this blend. The blend of alumina particles in the layer 14 is formed of a blend of 5-80wt.% ofγ-alumina and 20-95wt.% ofα-alumina, preferably, 10-65wt.% ofγ-alumina and 35-90wt.% ofα-alumina. Since ultraviolet rays are thus suitably reflected into the layer 16, the utilization of a phosphor can be improved.
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