| 摘要 |
PURPOSE:To suppress a rise of a starting voltage and lamp voltage of the lamp and decrease a deterioration of the luminous flux maintaining rate, by adding and sealing at least a kind of the lanthanium system rare earth metal, thorium, yttrium, scandium. CONSTITUTION:At both ends of a luminous tube bulb 1, are constructed crush sealed portions 2, 2. In the bulb 1, a pair of main electrodes 3, 3 are arranged apart in a face-to-face style to each other. In the bulb 1 are sealed a mercury, metal haloide and rare gas further added and sealed at least one kind among the lanthanium system rare earth metal, thorium, yttrium and scandium. The relation is made as follows. M>=3.0X10<-8>(gr atom/cc), log M>=18.1logN+77.6 where Ngr atom for mercury sealing quantity per unit volume and Mgr for sealing quantity of lanthanium system rare earth metal, thorium, yttrium, scandium metals per unit volume. |
