| 摘要 |
PROBLEM TO BE SOLVED: To improve color temperature stability of emission light while restricting light emission of a light-emitting tube; and to maintain durability when repeating switching-on and off. SOLUTION: A luminous envelope 1 for a high-intensity discharge lamp is a light-emitting tube 7 made of light-transmitting polycrystal ceramics, and the luminous envelope 1 includes: the light-emitting tube 7 having a central light-emitting section 7e, thick-walled sections 7d arranged on both sides of the central light-emitting section 7e and being thicker than that of the central light-emitting section, and side end sections 7c respectively arranged outside respective thick-walled sections; tube-shaped sections 3 respectively projected from respective side end sections; an electrode 5 arranged in an internal space of the light-emitting tube; electrode retaining members 2 inserted into respective tube-shaped sections and retaining the electrode; a sealing material 4 for sealing between the tube-shaped section and the electrode retaining member; and a shading film 11 for covering the whole periphery of external surfaces 7b of the thick-walled sections around the tube axis of the light-emitting tube. The external surfaces of the central light-emitting section 7e, the side end sections 7c, and the tube-shaped sections 3 are not covered with the shading film. COPYRIGHT: (C)2010,JPO&INPIT
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