| 摘要 |
PURPOSE:To lower the extent of operating temperature as well as to aim at improvement in a starting characteristic and prevention of a light flux drop, by using an Os-W alloy, regulating a rate of Os content as specified, for an electrode shaft and at least one side of coils, and forming an electrode for a light emitting tube. CONSTITUTION:A coil 7 made up of winding a tungsten wire is installed in an electrode shaft 6 consisting of an Os-W alloy wire setting a rate of Os content down to a range of 0.05-10% (weight percentage), and electron radioactive material 8 consisting of a mixture of an alkaline earth metallic oxide and a high melting-point oxide is stuck to the coil 7, forming an electrode 3B. And, it is used as an electrode of a light emitting tube available for an electric discharge lamp such as a mercury lamp and a high pressure sodium lamp. Therefore, a rate of Os content is regulated whereby operating temperature in the electrode 3B can be made reducible, and a starting characteristic is improved, while evaporation and scattering of the electron radioactive material 8 and lessened, thus tube wall blackening is reducible.
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