SEALING BODY FOR DISCHARGE LAMP

摘要

A sealing body (4) for a discharge lamp made of a functionally gradient material rich in nonconductive component on one side and rich in conductive component on the other side, and connected to a side pipe (3) connected to the arc tube (2) of the discharge lamp at the region rich in nonconductive component. An electrode core rod (7) having an electrode at one end is shrink-fitted in the sealing body (4). A tapered surface inclining with respect to the center axis of the discharge lamp is provided on the outer periphery side of the sealing body (4) in the region rich in nonconductive component in such a way that the maximum width B of the arc space side end face of the sealing body (4) is smaller than the maximum width M in the direction perpendicular to the axis of the sealing body (4) and larger than the diameter d of the electrode core rod (7). Thus, the variation of the pressure resistance of the sealing part is eliminated.