Abstract: A low-pressure mercury vapor discharge lamp (1) has a discharge vessel (3) enclosing, in a gastight manner, a discharge space provided with a filling of mercury and a rare gas. The discharge vessel (3) comprises means for maintaining an electric discharge in the discharge space. A portion of the surface (15) of the discharge vessel (3) facing the discharge space is provided with a protective layer (16) comprising yttrium oxide or aluminum oxide and further comprises a borate and/or a 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. Preferably, the further rare earth metal is lanthanum, cerium, and/or gadolinium. The lamp according to the invention has a comparatively low mercury consumption.

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.