Abstract: A low-pressure mercury vapor discharge lamp operates in either a first or a second mode of operation. The discharge lamp has a discharge vessel (1), enclosing a discharge space (8). A first end portion (11) of the discharge vessel is provided with a first electrode (12) and a first anode (13) in the vicinity of each other. A second end portion 21 of the discharge vessel is provided with a second electrode 22 and a second anode 23 in the vicinity of each other. While the discharge lamp operates in the first mode of operation, a discharge is maintained alternating between the first electrode and the second anode and between the second electrode and the first anode. While the discharge lamp operates in the second mode of operation, a discharge is maintained alternating between the first electrode and the first anode and between the second electrode and the second anode.

Abstract: Low-pressure mercury vapor discharge lamp has a light-transmitting discharge vessel (10) enclosing, in a gastight manner, a discharge space (13) 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). The discharge vessel is provided with a source of mercury (7). In addition, the discharge vessel is provided with a releasing means (8) for the controlled release of mercury vapor from the source of mercury. The releasing means is operative in response to a condition of the low-pressure mercury vapor discharge lamp, the condition being a characteristic of the discharge lamp and/or a predetermined time interval. The discharge lamp according to the invention operates under unsaturated mercury conditions. Preferably, the releasing means is operated via a switch device, preferably comprising a reed relay.

Abstract: Fluorescent lamp comprising a glass discharge vessel (2) in which an ionizable and vaporizable filling is present, which discharge vessel is on two sides provided with a tubular end portion including a glass stem, wherein an exhaust tube (6) extends axially outwardly from said stem for supplying and/or discharging gases during production of the lamp, wherein a main electrode (8) extends axially inwardly through the stem for generating and maintaining a discharge in the discharge vessel, and wherein the lamp comprises means including an auxiliary electrode (15) for controlling the pressure of said filling in the vapor phase, despite changes in temperature thereof, with the special feature that said auxiliary electrode is located on at least one end portion for generating and maintaining an auxiliary discharge between the main electrode and the auxiliary electrode.

Abstract: Low-pressure mercury vapor discharge lamp comprises a light-transmitting discharge vessel (10) enclosing, in a gastight manner, a discharge space (13) provided with a filling of mercury and a rame gas. The discharge vessel comprises discharge means (20a; 20b) for maintaining a discharge in the discharge space. The discharge vessel is provided with a container comprising an amalgam (2). The container is provided with releasing means (4) for the controlled release of mercury vapor from the amalgam. The releasing means is open during lamp operation and is substantially closed when, during lamp operation, the temperature of the amalgam becomes higher than a pre-determined temperature. Preferably, the predetermined temperature corresponds to a temperature of a range of temperatures at which the mercury-vapor pressure above the amalgam is relatively stable.