| abstract |
Low-pressure mercury vapor discharge lamp provided with a discharge vessel ( 10 ) which encloses enclosing a discharge space ( 11 ) provided with a filling of mercury and a rare gas in a gastight manner. The inner wall of the discharge vessel ( 10 ) is provided with a transparent layer ( 16 ) and a luminescent layer ( 17 ). According to the invention, the luminescent layer ( 17 ) is provided with a further transparent layer ( 18 ). Preferably, both transparent layers ( 16, 18 ) comprise an oxide of scandium, yttrium, or a further rare-earth metal, and/or a borate or phosphate of an alkaline-earth metal, and/or of scandium, yttrium, or a further rare-earth metal. Preferably, the alkaline-earth metal is calcium, strontium, and/or barium. The further rare-earth metal is preferably lanthanum, cerium, and/or gadolinium. The oxide is preferably Y2O3 or Gd2O3. The lamp according to the invention has a comparatively low mercury consumption. |