High pressure discharge lamp for DC operation - has two axially opposite inward protruding electrodes with high MP carrier pins and electrode forming cathode has at least two coils partly surrounding carrier pin

摘要

The first coil (17) in the region of the free end of the carrier pin (6) of the cathode, is designed in the shape of a winding extending along the axis (2) of the pin. This coil (17) is at least partly enclosed by a second coil (18) on its end aligned to the current lead in (10) of the bulb (1). The second coil (18) encircles an annular cavity (19) seen axially, connected at the end of the first coil, aligned to the bulb wall and its distance to this is restricted by a third coil (20). This coil is at least partly surrounded by the second coil. The coils on the carrier pin (6) end at a distance to the wall of the bulb (1), and the free end of the carrier pin is designed in the shape of a cone (21). USE/ADVANTAGE - Metallic vapour, e.g. Mercury HP discharge lamp. Gives high electrical output and designed to hold arc at tip of cathode and damage to glass is prevented. Gives higher working life.