| 摘要 |
PROBLEM TO BE SOLVED: To reduce mercury consumption during lighting and the blackening of a tube end, to lengthen life, and to increase brightness by forming a metal cylinder part with at least one of Mo, a compound containing Mo, Ta, and a compound containing Ta. SOLUTION: A pair of electrodes 3 is sealed so as to face each other within both ends of a glass bulb. The electrode 3 has a sleeve 4 made of at least one of high melting point metals such as Ta, Mo, and compounds containing them, and opened both ends, and the sleeve 4 is formed in a cylinder whose inner diameter is 0.4-1.5 mm and total length is 2.0-5.0 mm for example. By forming the electrode 3 so as to have the cylinder part whose facing inside surfaces are opened, electrons are easily emitted from the inner surface of the electrode by a shape effect such as a hollow cathode effect, and cathode drop voltage is reduced. Since metal of Mo and the like used as the material has high melting point and high electric conductivity and sputtering during discharge is suppressed.
|
