| 摘要 |
PURPOSE:To enable an accurate start under all operating conditions by providing a heat insulating body at the end of a luminous tube in which an electrode having the potential opposed to a starting auxiliary conductor and making the thermal conductivity of a conductor to this electrode smaller than the thermal conductivity of a conductor on the other end. CONSTITUTION:A starting auxiliary conductor 4 touches the outer surface of a luminous tube 1 at start and is separated from the outer surface of the luminous tube through a bimetal piece 5 at lighting. In addition, a heat insulating body 9 made of a heat resistant metal sheet is mounted on the outer surface of the side in which an electrode that has the potential opposed to the auxiliary conductor 4 at start is located so that the temperature of this section can relatively become higher than the temperature of the other end of the luminous tube 1 while a lamp is operating. Furthermore, for a conductor 10 that is positioned at the side where the insulating body 9 is provided, the thermal conductivity is reduced relatively, for example, by a method of reducing a crosssectional area, etc., as compared with a conductor 11 on the other end. |
