| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge lamp such as a cold-cathode fluorescent lamp capable of suppressing blackening of a glass bulb due to sputtering even if an emitter-impregnated sintered metal is used for an electrode head, high in light emission efficiency and having a long service life. SOLUTION: When it is assumed that the inside diameter of a cylindrical cup part-shaped part 4 and an axial length of an area which is formed on the opening side of the cylindrical cup part 4 without impregnating the emitter are R and L, respectively, the electrode head 3 of this discharge lamp 11 is so formed as to satisfy a relationship of L>R. COPYRIGHT: (C)2007,JPO&INPIT
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