Toshiba Lighting & Technology Corporation

Toshiyuki Nakamura

Kenji Sugiyama

Yoshiyuki Matsunaga

Ichiro Yamada

Takashi Yorifuji

A circular fluorescent lamp comprises a light-transmitting circular tube, filled with a discharge gas including mercury and a rare gas, having an outer diameter between about 14 mm and 18 mm. A phosphor layer is coated on the inner surface of the light-transmitting circular tube. A stem seals each end of the light-transmitting circular tube air-tightly, and holds a pair of conductive wires. One of the ends of each pair are connected to a filament, and the other of the ends extend outwardly from the circular tube. A lamp base is arranged between the ends of the light-transmitting circular tube so as to rotate slightly around the center axis of the circular tube and includes conductive pins, which are connected to the conductive wires. An insulator, arranged between at least one pair of the conductive wires, limits the movement of the conductive wires. The circular fluorescent lamp may be used for a lighting fixture.

Circular fluorescent lamp including an insulator between conductive wires, and a lighting fixture using the lamp

A low-pressure mercury vapor discharge lamp ( ) includes a translucent airtight container ( ), a pair of electrodes ( ) and ( &prime;) mounted in the airtight container ( ) and arranged at both ends and so that a distance of one of the electrodes from the sealing portions ( ) and ( &prime;) becomes longer than that of the other electrode, a mercury emission body ( ) filled in the airtight container and discharge medium including mercury discharged from the mercury emission body ( ) and inert gas. A cold spot is formed at one sealing portion ( ) of the low-pressure mercury vapor discharge lamp ( ) and mercury is filled by the mercury emission body ( ) and therefore, there is almost no excess mercury existing in the tube ( ), luminous flux starts up fast, mercury collected in the cold spot scarcely moves to other portion, and the lamp characteristic is stabilized.

Growing community of inventors

Kanagawa-ken, Japan

Toshiyuki Nakamura