LOWER TURN PER INCH (TPI) ELECTRODES IN CERAMIC METAL HALIDE (CMH) LAMPS

摘要

An electrode assembly (30, 32) for a discharge lamp (20), particularly a ceramic metal halide (CMH) lamp having a ceramic body (22), with a discharge chamber (24) and at least one leg (26, 28) having an opening therethrough. The electrode assembly is to be received at least in part in the body; it preferably includes a niobium mandrel (40), a molybdenum mandrel, and a molybdenum overwind (44) received over the mandrel. A tungsten portion (48, 50) is then joined to the molybdenum composite. Adjacent turns of the overwind are spaced by a gap to facilitate receipt of an associated seal material on the overwind and the molybdenum mandrel. The gap is approximately 10% to 50% of the dimension between adjacent turns of the overwind relative to a diameter of the overwind.