To provide a fluorescent lamp which provides good starting and stable light distribution, inhibiting an atmospheric discharge and preventing a position shift of an external electrode, by changing the shape of the external electrode to solve the problem that, in a fluorescent lamp with a cylindrical glass in which an internal electrode is placed and an external electrode made of an electric wire with a round cross section wound around the outer surface of the glass tube, a lot of spaces between the external electrode and the glass tube cause atmosphere discharges which damage the heat shrinkable tube.
Shape of an external electrode of the cross section has a relation of B/A≥50% between the maximum width A of the cross section parallel to the longer direction of the glass tube 11, and the contact width B of the external electrode 18 to the glass tube 11. The electrode is used for the external electrode 18 put around the outer surface of the glass tube 11.
YANO EIJU
Takehana Kikuo
Hiroshi Uji