| 摘要 |
PROBLEM TO BE SOLVED: To raise luminous efficiency by lengthening effective electric discharge path length. SOLUTION: It consists of a translucent electric discharge container 2 of an annular shape, whose annular outer diameter is 140 to 160 mm, and a ring outer diameter is 15 to 18 mm, a fluorescent substance layer 3, an electric discharge medium, small tube 4, which projects outside from one end of the translucent discharge container 2, inside of the translucent electric discharge container 2 is evacuated and is tipped-off after enclosure of the electric discharge medium, a 1st electrode 5 having a relatively high mounting height provided enclosed on one end side of the translucent electric discharge container 2, and a 2nd electrode 6 having a mounted height lower than the 1st electrode, provided enclosed on the other end side of the translucent discharge container 2. Moreover, it is constituted so that the lamp may be lightened with the lamp electric power of a range of 10 to 20 W, and the high frequency of 10 kHz or more. |
