Abstract: A high pressure discharge lamp having a translucent sintered aluminum oxide discharge envelope is produced by a method that includes providing a ceramic end plug having an aperture for a current lead-in member in an end of the envelope, sintering the end plug to the envelope and passing the current lead-in member through the plug so as to extend into the envelope, forming a thin disc-shaped sealing member formed of magnesium oxide containing glass frit and having an aperture for the lead-in member on the outer surface of the plug, positioning a thin barrier member having an aperture for the lead-in member on and extending over the outer surface of the sealing member and heating the assembly so as to cause the sealing member to melt and form a glass bond between the lead-in member and the plug and the barrier member to melt and bond to the glass seal.

Abstract: A high pressure discharge lamp having a translucent sintered aluminum oxide envelope, has a tubular current lead-in member, secured in a gas tight manner by an end-plug secured to the current lead-in member by a magnesium oxide containing glass seal and an aluminum oxide disk bonded to the outer surface of the end plug and extending over the glass seal.