| 摘要 |
PROBLEM TO BE SOLVED: To provide a metal halide lamp free from cracks at a contact part with a holder in an outer tube. SOLUTION: The metal halide lamp is provided with: a double-tube structure consisting of an arc tube with halogenated metal sealed as a light-emitting substance and an inner tube airtightly sealing the arc tube; a holder holding the double-tube structure; a lighting circuit for lighting the arc tube; a case containing the lighting circuit inside; and an outer tube attached to the case, made of a hard glass material, and containing the double-tube structure. A portion or whole of the outer periphery face of the holder is in direct or indirect contact with an inner periphery face of the outer tube, and the material of the holder satisfies: y×10<SP>7</SP>≤250×e<SP>-0.007x</SP>, wherein a thermal expansion coefficient of the material [/°C] is y, and a coefficient of thermal conductivity [W/(m K)] is x. COPYRIGHT: (C)2011,JPO&INPIT |
