Patent ID: 8004194

Claim:
A high-pressure discharge lamp with a ceramic discharge vessel with a central part and two tubular end regions, which are each closed by sealing parts by means of leadthroughs and glass solder, the glass solder consisting of a mixture of at least two oxides, electrodes being anchored in the sealing parts, which electrodes extend into the discharge volume, in each case the following components are contained in the sealing parts: the leadthrough, which holds the electrode and which consists of tungsten in the front part and of niobium-like material in the rear part, said leadthrough being introduced in a ceramic supporting part; the front tungsten part is a wire with a diameter DUW of at most 350 μm; the ceramic supporting part embedded in the sealing part has a total length LA over an embedding length of 2 to 8 mm; the front tungsten part is accommodated in the ceramic supporting part at least over a length LW of 1 mm; the aspect ratio LW/DUW, formed from the length of the front tungsten part and the diameter of the front tungsten part, is at least 10; for sealing purposes, in each case said glass solder is introduced into the gap between the tubular end region and the ceramic supporting part and into the gap between the ceramic supporting part and the leadthrough, said glass solder consisting of a mixture of at least two oxides, namely Al 2 O 3 of 30 to 90 mol %, with the remainder being at least one oxide of the rare earths yttrium Y, neodymium Nd, thulium Tm, dysprosium Dy.