JOINTED BODY, LUMINESCENCE ENVELOPE, AND ASSEMBLY BODY FOR HIGH PRESSURE DISCHARGE LAMP

PROBLEM TO BE SOLVED : To provide a jointed body in which a joining strength is high and in which a crack at a joining interface is prevented, in the jointed body of a first member in which at least a joining surface is composed of sapphire and a second member in which at least a joining surface is composed of sapphire or polycrystalline alumina. SOLUTION : A raw material for a joining material is interposed between the first member 2 and the second members 4A, 4B, and the first member and the second members are joined by heat-treating this raw material at 1, 730°C or less. Or, the joining members 5A, 5B are composed of oxide or oxynitride containing rare earth element, aluminum, and silicon, and the ratio of the silicon in the oxide or the oxynitride is 3 mol% or more and 10 mol% or less converted into silicon dioxide.