Abstract: A low-pressure mercury vapor discharge lamp has a light-transmitting discharge vessel (10) enclosing, in a gastight manner, a discharge space (11) provided with a filling of mercury and a rare gas. The discharge vessel (10) comprises discharge means for maintaining a discharge in the discharge space (13). At least a part of an inner wall (12) of the discharge vessel (10) is provided with a protective layer (16). The discharge vessel (10) is provided with a luminescent layer (17) comprising a luminescent material. The luminescent layer (17) further comprises inorganic softening particles (27) with a softening point above 450° C. The size of the softening particles (27) is in the range from 0.01 to 10 gm. Preferably, the softening particles (27) are selected from the group formed by strontium borate, barium borate, yttrium borate, yttrium-strontium borate and calcium pyrophosphate.

Abstract: A low-pressure mercury vapor discharge lamp has a light-transmitting discharge vessel (10) enclosing, in a gastight manner, a discharge space (11) provided with a filling of mercury and a rare gas. The discharge vessel (10) comprises discharge means for maintaining a discharge in the discharge space (13). At least a part of an inner wall (12) of the discharge vessel (10) is provided with a protective layer (16). The discharge vessel (10) is provided with a luminescent layer (17) comprising a luminescent material. The luminescent layer (17) further comprises inorganic softening particles (27) with a softening point above 450° C. The size of the softening particles (27) is in the range from 0.01 to 10 gm. Preferably, the softening particles (27) are selected from the group formed by strontium borate, barium borate, yttrium borate, yttrium-strontium borate and calcium pyrophosphate.

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: A low-pressure mercury vapor discharge lamp is provided with a discharge vessel (10). The discharge vessel comprises tubular end portions (11; 11′), which each have a longitudinal axis (12; 12′). The discharge vessel (10) encloses a discharge space (18) containing a filling of mercury and an inert gas in a gastight manner. Electrodes (20; 20′) are arranged in the discharge space (18). An auxiliary amalgam is provided on a carrier (25; 25′) in the proximity of the electrodes (20; 20′). According to the invention, a part of the carrier (25; 25′) is arranged in a plane transverse to the longitudinal axis (12; 12′). Preferably, a stem (21; 21′) in the tubular end portion (11; 11′) carries, apart from the electrode (20; 20′), a support in the form of a wire (23; 23′) or an extended exhaust tube, which support carries the carrier (25; 25′). In an alternative embodiment, the carrier is clamped directly onto the stem.