Patent ID: 6642654
Filing Date: 2003-11-04
Classification: C04B,H01J

Abstract:
A high pressure discharge lamp comprising:a ceramic discharge tube with an inner space formed therein and end portions, said inner space being filled with an ionizable light-emitting material and a starter gas and an opening being formed within said end portion; an electrode system provided within said inner space; a sealing member comprising a ceramic or a cermet with a through hole formed therein, at least a part of said sealing member being fixed within said opening of said ceramic discharge tube; and a metal member; wherein said lamp comprises a joined body interposed between said metal member and said sealing member, said joined body comprising a joining portion interposed between said metal member and said sealing member for joining said metal and said sealing members, said joining portion comprising a main phase contacting said metal member and an intermediate ceramic layer contacting said sealing member and existing between said sealing member and said main phase, wherein said main phase comprises a porous bone structure having open pores and made of a sintered product of powder of a metal, and said main phase further comprises a ceramic phase impregnated into said open pores of said porous bone structure, wherein each of said intermediate ceramic layer and said impregnated ceramic phase has a crystallinity of more than 50%.