Abstract: There is provided a multi-ringed bulb including a plurality of ring bulbs in which a plurality of straight tube portions having an outside diameter of from 12 to 20 mm are connected to each other through bent portions on a same plane. Electrodes are provided hermetically at respective ends of outermost and innermost bulbs of the plurality of ring bulbs. A connection portion connects other adjacent ends of the outermost and innermost bulbs to each other so that the outermost and innermost bulbs communicate with each other, to form a single discharge path. A phosphor layer is formed on inner surfaces of at least the straight tube portions 5a of the inner and outer bulbs. The multi-ringed structure bulb is filled with discharge medium. The above-mentioned structure permits to provide a fluorescent lamp and a lighting apparatus, which have a small strain in the inner and outer bulbs, a high strength and an excellent luminous efficiency.

Abstract: A fluorescent lamp includes: a bulb including bent and straight-tube portions having an external tube diameter of 12 to 20 mm and a tube length of 800 to 2500 mm. The straight portions are disposed generally within the same plane through the bent portions. A pair of end portions with electrodes sealed therein form a single discharge path through the straight tube and bent portions. A phosphor layer is formed on the inner face of the bulb, and a discharge medium including mercury is sealed in the bulb. Thermal deterioration of the phosphor layer formed at the straight tube portions is reduced so deterioration of the initial light flux is suppressed, allowing lighting at higher efficiency. With the above configuration, a fluorescent lamp is compact and capable of light with high efficiency, and with improved light output properties. A light fixture uses this fluorescent lamp.

Abstract: A fluorescent lamp 1 comprises: a bulb 2 formed by heating bent-portion-formation preordination portions of a single straight-tube-shaped bulb 2a having an external tube diameter of 12 to 20 mm and a tube length of 800 to 2500 mm, forming a plurality of bent portions 2c and straight tube portions 2b adjacent to the bent portions 2c by bending processing, such that the straight portions 2b are disposed generally within the same plane by way of the bent portions 2c, forming in close proximity a pair of end portions 2d and 2d with electrodes 5 and 5 sealed in so as to form a single discharge path through the straight tube portions 2b and bent portions 2c, forming a phosphor layer 4 on the inner face of the bulb, and sealing a discharge medium including mercury; and a base 6 provided on the end portions 2d and 2d of the bulb 2; whereby thermal deterioration of the phosphor layer 4 formed at the straight tube portions 2b is reduced so deterioration of the initial light flux is suppressed, allowing lighting at high

Abstract: There is provided a multi-ringed bulb including a plurality of ring bulbs in which a plurality of straight tube portions having an outside diameter of from 12 to 20 mm are connected to each other through bent portions on a same plane. Electrodes are provided hermetically at respective ends of outermost and innermost bulbs of the plurality of ring bulbs. A connection portion connects other adjacent ends of the outermost and innermost bulbs to each other so that the outermost and innermost bulbs communicate with each other, to form a single discharge path. A phosphor layer is formed on inner surfaces of at least the straight tube portions 5a of the inner and outer bulbs. The multi-ringed structure bulb is filled with discharge medium. The above-mentioned structure permits to provide a fluorescent lamp and a lighting apparatus, which have a small strain in the inner and outer bulbs, a high strength and an excellent luminous efficiency.