Patent ID: 8390196

Claim:
A metal halide lamp ( 25 ) comprising a ceramic discharge vessel ( 1 ), wherein the discharge vessel ( 1 ) has a wall ( 30 ) enclosing a discharge space ( 22 ) with an ionizable filling, the discharge space ( 22 ) further enclosing electrodes ( 4 , 5 ) having electrode tips ( 4 b , 5 b ) arranged opposite each other and arranged to define a discharge arc between the electrode tips ( 4 b , 5 b ) during operation of the lamp ( 25 ), the discharge vessel ( 1 ) having a spheroid-like shape with a major axis ( 60 ) and a length L 1 , a largest inner diameter d 1 and a largest outer diameter d 2 and further having curved extremities ( 114 , 115 ), each having a curvature with radius r 3 and a center of curvature located within the discharge space ( 22 ), wherein an aspect ratio L 1 /d 2 is 1.1≦L 1 /d 2 ≦2.2 and a first shape parameter r 3 /d 2 is 0.7≦r 3 /d 2 ≦1.1 wherein the major axis is substantially parallel to a line formed between said electrode tips.