Metal halide lamp with ceramic discharge vessel

A metal halide lamp with ceramic discharge vessel, the discharge vessel having two ends that are sealed with ceramic stoppers that in each case contain an elongated capillary tube, termed stopper capillary below, of inside diameter K, and wherein an electrically conducting lead-through, which comprises an inner part and an outer part with reference to the discharge, is guided through this stopper capillary and is sealed outside with glass solder such that the outer part of the lead-through is sealed with glass solder over its length located in the stopper capillary, while an area, adjacent thereto, of the inner part of the lead-through is sealed over a small part of the length of from 1 to 2 mm by glass solder, there being fastened on the lead-through an electrode with a stem that projects into the interior of the discharge vessel, the outside diameter S of the inner part being coordinated with the inside diameter K, wherein the inner part is a composite component that comprises a core pin of diameter D onto which there is mounted as a double ply a coil with an effective diameter d of the coil wire, the following relationships being fulfilled:

• 0.8 K≦S≦0.98 K
• d≦D
• Dmax≦0.5 mm
• 0.16 K≦D≦0.40 K
• 0.10 K≦d≦0.195 K.