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: Low-pressure mercury vapor discharge lamp having a discharge vessel filled with mercury and a rare gas, which discharge vessel comprises two substantially parallel, mainly rectangular flat glass plates located at a relatively short distance from each other and being transparent to light, which plates are connected together in a gas-tight manner proximate their circumference and form upright walls. Electrodes, between which a discharge is maintained in the discharge vessel during operation arranged on the outer side of the discharge vessel. The electrodes are in the form of strips of conducting material which are arranged on at least two facing upright walls and which extend substantially throughout the length of these walls.

Abstract: Electrodeless low-pressure discharge lamp having a lamp vessel which is sealed in a gas-tight manner and which is filled with a metal vapor and a rare gas and which has a core of a magnetic material. During operation of the lamp an electric field is generated in the lamp vessel by means of a winding surrounding the core and a high-frequency supply unit connected thereto. A transparent electrically conducting layer is present on the inside of the lamp vessel, and is connected to an electric conductor located outside the lamp vessel by means of a lead-through member incorporated in the wall of the lamp vessel. The lead-through member is electrically connected to a contact strip of conducting material extending on at least the greater part of the circumference on the inside of the lamp vessel and is electrically connected substantially throughout its length to the transparent conducting layer.