Patent ID: 6911775

Claim:
Short-arc, ultra-high pressure discharge lamp which comprises: a light emitting part in which there is a pair of opposed electrodes and which is filled with at least 0.15 mg/mm 3 of mercury; and side tube parts which extend from opposite sides of the light emitting part, and in each of which a respective one of the electrodes is partially hermetically sealed and is joined to a respective metal foil, wherein each metal foil has a cross section with an essentially inverted W-shape, and wherein each electrode is located and welded in a central valley area of the essentially inverted W shape of the respective metal foil, and wherein the central valley area has a maximum height of 0.2 mm to 1.0 mm, a portion of each electrode located in the valley area has a diameter of 0.2 mm to 1.0 mm and the outside diameter of each side tube part is 4.0 mm to 9.0 mm.