Easily-assembled compact self-ballasted fluorescent lamp

摘要

A compact self-ballasted fluorescent lamp includes an arc tube formed by a glass tube double-spirally wound from its middle to both ends around a spiral axis, and a cylindrical holding member having a closed bottom and holding the arc tube, a case fit to cover a circumferential wall of the holding member, and the like. End-vicinity parts of the glass tube are formed to have a larger gap with glass tube parts adjacent in the direction of the spiral axis. The arc tube is held in a state where the distance L1 between a first point that is on an outer surface of a glass tube part adjacent to one of the ends of the glass tube in the direction of the spiral axis and a second point on a surface of the end wall facing the first point is about 1.5 mm.