| 摘要 |
A multi-ringed fluorescent lamp (FL) includes a multi-ringed bulb (1), a phosphor layer (2) formed on an inner surface of the bulb (1), a pair of electrodes (3) and discharge medium with which the bulb (1) is filled. The bulb (1) includes ring bulbs (1A,1B) in each of which straight portions (1a,1bC,1bD) and bent portions (1c) are placed alternately on a same plane, by bending partially a glass tube having an outside diameter of 12-20 mm into a rectangular shape, so that opposite ends of the tube terminate with the adjacent straight portions (1bC). The ring bulbs (1A,1B) are placed concentrically on the same plane and connected through a bridge connection portion (1C) to form a single discharge path. A gap between adjacent bent portions (1c) is larger than a gap between adjacent straight tube portions (1a,1bC,1bD) and has a maximum value of 6-15 mm. The electrodes (3) are provided in opposite ends of the discharge path of the multi-ringed bulb. |
