Abstract: A discharge lamp is provided with a tubular discharge vessel having an internal diameter of at most 5 mm, with a luminescent screen, and with a filling which comprises mercury and a rare gas. The rare gas comprises more than 98 mole % neon, and the luminescent screen comprises a first group and a second group of luminescent substances, which first group comprises luminescent substances for converting UV radiation generated by mercury into visible light, and which second group comprises luminescent substances for converting the UV radiation generated by neon into visible light. The discharge lamp has a comparatively high luminous flux immediately after ignition even in cold surroundings.

Abstract: A meander-shaped low-pressure mercury discharge lamp with cold electrodes (7, 8), in particular for use in an illumination panel for a liquid crystal display. The geometry of the tubular lamp vessel (1) bent into a meander shape is so chosen, for obtaining a good homogeneity of the luminance and a high luminous efficacy, that the length of the discharge path is between 250 and 1000 times the internal diameter of the lamp vessel (1). The internal diameter of the lamp vessel (1) preferably has a value of between 2.0 and 3.5 mm.

Abstract: A low-pressure mercury vapour discharge lamp according to the invention is provided with a radiation-transmitting discharge vessel (10) which encloses a discharge space (11) in a gastight manner and comprises mercury as well as a rare gas. Mercury is also present in a vapour pressure control member (21) which is in communication with the discharge space (11) during nominal operation. The discharge lamp has means (40) for maintaining a discharge in the discharge space (11). The vapour pressure control member (21) forms part of a mercury control member (20) which also comprises mercury transport control means (22) which limit the mercury transport from the discharge space (11) to the vapour pressure control member (21), at least while the lamp is out of operation, to such an extent that this transport is at most 5 ng/h.cm.sup.3, measured at room temperature and in the presence of a saturated mercury vapour in the discharge vessel, per unit volume of the discharge space.

Abstract: A lighting unit includes a discharge vessel having a wall provided with a first luminescent layer, a gas fill consisting essentially of neon at a pressure less than 30 mbar, and a means for providing a constant DC current for exciting the fill in the discharge vessel to emit UV light for exciting the luminescent layer. DC operation offers substantially higher luminous flux over AC operation. The lighting unit may further include a housing having a reflective surface, a second luminescent layer, and a filter incorporated within the discharge vessel.

Abstract: A low-pressure mercury vapor discharge lamp according to the invention is provided with a discharge vessel (10) which encloses a discharge space (11) containing mercury and a rare gas in a gaslight manner. The discharge vessel (10) has a light-transmitting tubular portion (12) and a first and a second end portion (13A, 13B). Current supply conductors (20A, 20A'; 20B, 20B') issue through each end portion (13A, 13B) to respective electrodes (21A, 21B) arranged in the discharge space (11). The lamp is further provided with a main amalgam (30) for stabilizing the mercury vapour pressure in the discharge space (11) during normal operation, and with an auxiliary amalgam (31A, 31B) for quickly releasing mercury into the discharge space (11) after switching-on of the lamp. In an equilibrium state at room temperature (25.degree. C.), the mass (m.sub.Hg in mg) of the quantity of mercury absorbed in auxiliary amalgam (31A, 31B) is at most 20 times the mercury vapour pressure (P.sub.

Abstract: A low pressure discharge lamp having a tubular discharge vessel (1). At each of its end portions (2, 3) the vessel (1) is fused to a respective metal tube (5) having an uncovered outer surface outside the vessel. A sealed glass tube (6) is fused to the metal tubes (5). Ignition aids (18, 28, 40) may also be present. The simple construction of the lamp permits manufacture and high lamp quality, even at long lengths and/or small diameters of the discharge vessel. The lamp may have an ionizable filling of rare gas or may also contain mercury. A fluorescent powder may also be present in the discharge vessel. The lamp (72) and a luminaire (70, 71) mounting the lamp may be used for display or signalling purposes.

Abstract: An electrodeless low-pressure mercury vapor discharge lamp whose discharge vessel is provided with a core of magnetic material and a coil surrounding the core which coil connected to a high-frequency supply unit. An interference-suppressing, light transmissive electrically conductive layer is present on the outside of the discharge vessel, which layer can be connected to the supply mains through an electric conductor. The electric conductor comprises one or several capacitors connected in series to keep the conducting layer safe to touch during operation.

Abstract: A low-pressure mercury vapour discharge lamp having a tungsten coil electrode which is supported at either end by a respective current supply wire and which has emitter-coated central turns and, on either side thereof, end turns which are free from emitter. Each of the current supply wire ends with adjoining end turns of the coil is surrounded by an electrically insulating sleeve, such as a glass tube, as a result of which the switching life of the lamp is considerably increased.

Abstract: Low-pressure mercury vapor discharge lamp having a curved discharge vessel in which a mercury discharge is maintained between the electrodes and in which furthermore an amlagam is provided to control the mercury vapor pressure, the discharge vessel containing a rare gas mixture which contains at least 50 at.% krypton at a pressure of 130 to 520 Pa.

Abstract: Low-pressure mercury vapor discharge lamps provided with a luminescent layer and having a relatively high power consumption. Lamps are loaded by at least 500 W per m.sup.2 surface area of the luminescent layer. In some embodiments the lamps have a nominal length of 60 to 150 cm and consume a nominal power of 0.25 to 0.50 W per cm length of the discharge tube.

Abstract: Low-pressure mercury vapor discharge lamp having a relatively small discharge vessel containing as the buffer gas a rare gas mixture which is rich in helium, but which also comprises a quantity of one or more heavier rare gases, preferably crypton. The heavier rare gases increase the arc voltage.