| 摘要 |
PROBLEM TO BE SOLVED: To prolong the lifetime of a vacuum ultraviolet ray lamp. SOLUTION: A vessel 1 of a vacuum ultraviolet ray lamp is filled with a rare gas such as argon, krypton, xenon and shut tightly by a dielectric substance 2 to serve also as a vacuum ultraviolet ray takeout window. Electrodes 4 and 4a are installed opposing with the window 2 interposed and connected to a high-frequency, high-voltage power supply 6 through leads 5. The material of this dielectric substance, or takeout window member, should preferably be fluoride not containing oxygen such as magnesium fluoride, lithium fluoride, or calcium fluoride, and there is no risk that oxygen likely to cause damping of the light-output is emitted into the vessel even if it is irradiated with light energy. Thereby damping of the long-time light output is suppressed. Damping of the vacuum ultraviolet ray does not constitute any practical problem because the generated oxygen is emitted to outside the vessel even though quartz or sapphire containing oxygen is used if the rare gas in the vessel is substituted at normal times.
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