| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a fluorescent lamp in which the total luminous flux and luminous efficiency of the lamp are improved by lengthening the discharge path with the same maximum outer diameter as that of a conventional fluorescent lamp, and the coldest point temperature is lowered. <P>SOLUTION: Three or more circular luminous tubes having different diameters are provided substantially concentrically in substantially the same plane, and the ends of the circular luminous tubes are linked sequentially by bridge joints. One discharge path is formed of the electrodes provided, respectively, at the ends of circular luminous tubes of the outermost ring and the innermost ring. One cap is provided to surround the end of a circular luminous tube on the electrode side provided therein, and the discharge path is lengthened by linking different circular luminous tubes by bridge joint. The total luminous flux and luminous efficiency of the fluorescent lamp are improved and the coldest point temperature is lowered by lighting the lamp with a lamp current in an optimum range. <P>COPYRIGHT: (C)2013,JPO&INPIT |
