Abstract: Low-pressure mercury vapor discharge lamp has an at least partly substantially cylindrical discharge vessel (10) with a length Ldv and with an internal diameter Din. The discharge vessel (10) encloses, in a gastight manner, a discharge space (13) provided with a inert gas mixture and with mercury. The discharge vessel (10) comprises discharge means (electrodes 20a; 20b) for maintaining a discharge in the discharge space (13). According to the invention, the ratio of the weight of mercury mHg in the discharge vessel (10) to the product of the internal diameter Din and the length of the discharge vessel Ldv is given by the relation: Formula (I), wherein C?0.01 ?g/mm2. Preferably, 0.0005?C?0.005 ?g/mm2. Preferably, the discharge vessel (10) contains less than 0.1 mg mercury. The discharge lamp according to the invention operates under unsaturated mercury conditions.

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 has an at least partly substantially cylindrical discharge vessel (10) with a length Ldv and with an internal diameter Din. The discharge vessel (10) encloses, in a gastight manner, a discharge space (13) provided with a inert gas mixture and with mercury. The discharge vessel (10) comprises discharge means (electrodes 20a; 20b) for maintaining a discharge in the discharge space (13). According to the invention, the ratio of the weight of mercury mHg in the discharge vessel (10) to the product of the internal diameterDin and the length of the discharge vessel Ldv is given by the relation: wherein C (0.01(g/mm2. Preferably, 0.0005 (C(0.005(g/mm2. Preferably, the discharge vessel (10) contains less than 0.1 mg mercury. The discharge lamp according to the invention operates under unsaturated mercury conditions.

Abstract: In a fluorescent lamp mercury consumption is reduced by embedding the luminescent particles making up the luminescent layer in a matrix of aluminum phosphate comprising aluminum oxide particles and covering the embedded luminescent particles with a top coating of e.g. yttrium oxide.

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.