| 摘要 |
PROBLEM TO BE SOLVED: To provide a discharge lamp having small leak current. SOLUTION: A discharge lamp 1 has a luminescent tube 2 as a straight tube shaped inner tube and is provided with cool cathode 3, 3 via a lead wire 3a on both ends of this luminescent tube 2. Around the luminescent tube 2, an outer tube 5 surrounding the luminescent tube 2 is provided via a clearance 4 of a vacuum pressure of substantially 10<-5> Torr. A gas absorption better member 6 is housed in the clearance 4. A voltage is applied between cool cathodes 3 and 3 by a lightning circuit 7, and the lamp is started and lit. Mercury vapor is excited by discharge between cool cathodes 3 and 3, a ultra-violet ray of 147nm and 254nm in wavelength is excited, and a three-wave length phosphor is light-emitted. Since a clearance 4 is substabtuyally vacuum of 10<-5> Torr, a floating capacity decreases, discharge from the luminescent tube 2 to a proximal conductor becomes small, a leak current can be lowered, a triggering voltage can be lowered, and a lighting maintenance current can be reduced. |
