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 compact screw-base discharge lamp having an electrical stabilization ballast which occupies a central position in the lamp. The discharge vessel surrounds the ballast. To dissipate the heat generated by the ballast during operation to the environment of the lamp, a thin-walled heat sink of a heat-conductive material is provided between the ballast and the discharge vessel, and bears on the ballast. This body has a collar which extends to the exterior of the lamp.

Abstract: Low-pressure mercury vapor discharge lamp having an electrical stabilization ballast 10 which occupies a central position in the lamp. The discharge vessel surrounds the ballast.In order to dissipate the heat generated by the ballast during operation to the environment of the lamp, a thin-walled heat sink of a heat-conductive material which bears on the ballast is provided between the ballast and the discharge vessel, this body having a collar which extends as far as the exterior of the lamp.

Abstract: Low-pressure sodium vapor discharge lamp comprising a hollow inner member surrounded by an outer member, the wall of at least one of the members having grooves and the members of that portion, located between the grooves, extending to or to near the wall of the other member and a discharge space being formed wherein a discharge path, folded by means of the grooves, is present, the portions located between the grooves and facing the wall of the other member and extending to or to near the wall of the other member being provided with intervening portions extending in parallel with that wall.

Abstract: Low-pressure mercury vapor discharge lamps of the fluorescent type are known which comprise two nesting glass members so grooved as to provide between their nesting surfaces a circuitous ("folded") discharge path between two electrodes, the length of the discharge path being considerably greater than the physical distance between the electrodes. The whole surface of each glass member is coated with luminescent material with the result that, when the lamp is in use, the portions of the members not surrounding the discharge appear dark due to their poor light transmissibility. According to the invention, these portions of the two members are not coated with luminescent material and thus act as windows for light generated in the luminescent layers facing the lamp axis. Preferably, a fluted reflector is provided inside the lamp.

Abstract: Low-pressure discharge lamp having a discharge space, limited by an elongate lamp vessel, electrodes at one end of the vessel in the discharge space between which electrodes a discharge takes place during operation of the lamp. The lamp vessel has partitions to divide the discharge space into each extending substantially in the length of the discharge vessel which chambers communicate with one another via at least one opening. The chambers are sequentially passed through by the discharge, the opening between at least two chambers being at least partly wedge-shaped, the minimum width being located nearest to an electrode whose discharge path extends itself after ignition.

Abstract: A gas discharge laser in which at least the inner wall of the laser tube is manufactured for the greater part from a gehlenite glass thereby providing a laser having a long life. The gehlenite glass can better withstand the eroding effect of the gas discharge so that the rate at which the optical elements are contaminated is greatly reduced.

Abstract: A pressure energy accumulator having a mixture consisting of CF.sub.4 or C.sub.2 F.sub.6 and N.sub.2, H.sub.2, or He, or a combination thereof, as the gaseous working medium.

Abstract: A low-pressure mercury vapor discharge lamp having a discharge space provided with two thermally emitting electrodes as well as an amalgam of bismuth, indium and mercury, characterized in that the ratio of atoms of bismuth to atoms of indium is between 0.4:0.6 and 0.7:0.3 and the ratio of atoms of mercury to the sum of the atoms of bismuth and indium is between 0.01:0.99 and 0.15:0.85.

Abstract: The invention relates to a device for operating a low-pressure sodium vapor discharge lamp without a stabilizing ballast.The lamp is provided with a discharge tube having first and second main electrodes opposing a third main electrode. An automatically operating change-over switch occasionally switches the lamp current to either the first or second electrodes. A reservoir of liquid sodium near the first electrode affects sodium vapor pressure in the discharge tube by the switching action.