Short arc discharge lamp e.g. short arc mercury lamp, for use in e.g. printed circuit board, has fine longitudinal opening formed from anode-sided tip end to base, and micro cracks formed at inner surfaces of opening

摘要

The lamp (1) has an illuminant section (11) with a cathode (20) and an anode arranged opposite to each other, where the cathode contains material that emits electrons. A fine longitudinal opening is formed from an anode-sided tip end to a base, and micro cracks are formed at inner surfaces of the opening. The opening has a diameter in the range of 0.2 mm to 1 mm and depth in the range of 2 mm to 10 mm. The micro cracks have depth in the range of 5 to 30 micrometers. The cathode is made of tungsten, and the material is selected from a group consisting of thorium, lanthanum, cerium and yttrium.