Patent ID: 6646379
Filing Date: 2003-11-11
Classification: H01J

Abstract:
A metal vapor discharge lamp having an arc tube comprising:a discharge portion composed of translucent ceramic in which a discharge metal is filled and a pair of electrodes is disposed; small tubular portions composed of ceramic coupled to both ends of said discharge portion, the surfaces including the respective end faces of the small tubular portions defining a discharge space in cooperation with the inner surface of said discharge portion; feeder bodies composed of a conductive cermet inserted into said small tubular portions, the end portion of the feeder bodies being connected to respective said electrodes; and a sealing material of a glass frit for sealing the gap between said feeder body and said small tubular portion at the end portion opposite to said discharge space, wherein the ends of the conductive cermets and the end face of the glass frit on the discharge space side are recessed from the discharge space, the ends of the conductive cermets on the side opposite to said discharge space extend at least to the ends of said small tubular portions, and the temperature of the end face of said sealing material on the discharge space side during the lamp operation is not more than 800Â° C.