An arc discharge metal halide lamp having a discharge chamber with visible
light permeable walls bounding a discharge region through which walls a
pair of electrode assemblies are supported with interior ends thereof
positioned in the discharge region spaced apart from one another. These
electrode assemblies each also extend through a corresponding capillary
tube affixed to the walls to have exterior ends thereof positioned
outside the arc discharge chamber. At least one of these electrode
assemblies comprises an electrode discharge structure with a discharge
region shaft extending into the capillary tube corresponding thereto. A
discharge region shaft extends outwardly in that corresponding capillary
tube to be in direct contact with an interconnection shaft extending
outside of that corresponding capillary tube to provide an exterior end
of this electrode assembly, and which is in direct contact with a sealing
cap over the end of the tube.