Patent attributes
A multi-ringed fluorescent lamp includes a multi-ringed bulb, a phosphor layer formed on an inner surface of the bulb, a pair of electrodes and discharge medium with which the bulb is filled. The bulb includes ring bulbs in each of which straight portions and bent portions 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. The ring bulbs are placed concentrically on the same plane and connected through a bridge connection portion to form a single discharge path. A gap between adjacent bent portions is larger than a gap between adjacent straight tube portions and has a maximum value of 6-15 mm. The electrodes are provided in opposite ends of the discharge path of the multi-ringed bulb.
