| 摘要 |
A ceramic envelope device for a high-pressure metal-vapor discharge lamp, including a translucent ceramic arc tube, a pair of electrically conducting cermet end caps closing opposite open ends of the ceramic arc tube, and having opposite inner surfaces facing each other, the end caps having a pair of inner holes formed in the opposite inner surfaces of the end caps, respectively, and a pair of discharge electrodes each provided in the form of a rod, having first ends supported in the inner holes in the end caps, respectively, and second ends which protrude from the opposite inner surfaces toward each other in a longitudinally inward direction in the ceramic arc tube. To fix each electrode in the corresponding hole by shrinkage fit with reduced thermal stresses during sintering of the end caps, at least one strand is inserted in each of the inner holes in the end caps, such that there exists an axial space between outer surfaces of the discharge electrode and the at least one strand, and an inner surface of the corresponding inner hole. Each strand has a diameter and a length smaller than those of the rod of the electrode.
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