| 摘要 |
PROBLEM TO BE SOLVED: To provide a long-life ultra-high pressure discharge lamp and electrodes for the lamp capable of preventing damage to the lamp by cracks generated on the electrode sealing portions and having a high reliability of resistance to breakage. SOLUTION: The ultra-high pressure discharge lamp is so constructed that a pair of electrodes are displaced opposite to each other, mercury vapor of 0.15 mg/mm<SP>3</SP>or more is sealed in the discharge container, the end of each electrode is welded to a metal foil embedded in the sealing portion, and each metal foil and part of each electrode are sealed with glass. Each of the electrodes has a large-diameter portion which is approximately symmetrical about the axis of the lamp in the full length and a reduced-diameter portion linked to the large-diameter portion. The electrode is formed in a body with an external surface connecting the large- and reduced-diameter portions and the surface of portion of the electrode sealed by the glass is streak-shaped along the direction of the axis of the electrode and has a patterned indented surface over the whole sectional peripheral surface which is orthogonal to the direction of the axis. COPYRIGHT: (C)2009,JPO&INPIT
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