| 摘要 |
PURPOSE:To make it possible to securely start a luminous tube of a metal vapor discharge lamp, by enclosing mercury or 10<-4>-10 Torr gas into an outer tube and with the scatter of surge voltage suppressed by housing a starting circuit built up with two heating resistors and a heat responsive switch connected in series. CONSTITUTION:Two heating resistors 6a, 6b made by coiling tungsten wire are fixed, and a starting circuit 5 built up by connecting in the order of the first heating element 6a, a bimetal piece 9 acting as a heat responsive switch and the second heating element 6a in series and a luminous tube 1 are housed in an outer tube 20, and mercury, 10<-4>-10 Torr gas or the mixture of mercury and the gas is enclosed in the outer tube 20 instead of argon. Thereby, being able to diminish the dispersion of a surge voltage, the dielectric breakdown of a lighting circuit is prevented, and the secure start of the luminous tube is guaranteed. |
