| 摘要 |
PROBLEM TO BE SOLVED: To provide a ceramics electrode structural body, in which a ceramics electrode is securely fixed and circulation of electric discharge to a holder is hardly generated, a discharge lamp and a lighting system using the ceramics electrode structural body. SOLUTION: A ceramics electrode 1 is configured such that a ceramics container 1b contains therein electron emitting substance 1a made of granular, spongy or bulky composite ceramics, which includes mainly oxide composed of an alkaline earth element and a transition metal element and is covered at the surface thereof with carbide and/or nitride of a transition metal element. When the ceramics electrode 1 is fixingly contained in a metallic cylindrical holder 2, at least bottom portion of the ceramics container 1b is contained, and a circumferential edge 2a of an opening is caulked to form caulking portions 2b for fixture. Caulking the circumferential edge 2a of the opening of the metallic cylindrical holder 2 can reduce a gap (g) between the circumferential edge of the metallic cylindrical holder 2 and the ceramics container 1b so as to make it difficult to generate circulation of electric discharge to the metallic cylindrical holder 2 by a hollow effect, and further, can maintain stable electric discharge without any luminance flicker until the end of the lifetime of the electrode.
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