Abstract: A gas discharge lamp (1) equipped with a gas discharge vessel (2) enclosing a gas filling, said gas filling comprising a chalcogen selected from the group of sulfur, selenium or tellurium or a compound thereof, and with means for igniting and maintaining a gas discharge, comprising an electrode assembly (6-9) disposed in the discharge vessel, the electron-emissive material (9) of the electrode assembly comprising iridium or an alloy of iridium, providing a long-lived, efficient, compact, and high intensity white light source for applications such as general and professional illumination.

Abstract: Lighting apparatus includes a dielectric barrier discharge lamp having a discharge vessel enclosing a discharge space having a filling, first and second main electrodes, a dielectric sheet between the first main electrode and the discharge space, and a first circuit part for generating an operating voltage between the main electrodes. A plurality of electrode bodies mounted in or on the dielectric sheet form an auxiliary electrode, and a second circuit part generates auxiliary voltages between the electrode bodies for generating an auxiliary discharge in the discharge space.

Abstract: A high-pressure metal halide discharge lamp has opposed tungsten electrodes carried by electrode rods. These rods have a first portion of tungsten adjacent the electrodes and a second portion made of at least 25% by weight of rhenium. Their common boundaries are at a location having an operating temperature in the range of 1900-2100° K. The gas filling contains metal oxyhalide and is devoid of rare earth metal compounds.

Abstract: The high-pressure metal halide discharge lamp has opposite tungsten electrodes (5) carried by electrode rods (7). These rods (7) have a first portion (71) of tungsten adjacent the electrodes (5) and a second portion (72) having a core of tungsten and a skin of at least 90% by weight of rhenium. Their common boundaries are at a location having during operation a temperature in the range of 1900-2100 K. The gas filling contains metal oxyhalide and is devoid of rare earth metal compounds. The lamp has a long life and a high luminous maintenance.

Abstract: The high pressure metal halide lamp has in a light transmitting discharge vessel discharge electrodes and a filling made of a rare gas, a buffer gas and at least one halide chosen from hafnium and zirconium bromide and chloride. The filling also includes a metal chosen from tin, tantalum and antimony in elementary form and is free from iodine in an amount exceeding 0.5 .mu.mol/cm.sup.3 discharge space. The lamp has considerably improved light generating properties.

Abstract: The high-pressure discharge lamp has a filling in a discharge vessel (1) which includes a rare gas and a metal compound (2) chosen from hafnium halides and zirconium halides. The halide evaporates and discomposes to form incandescent, condensed metal particles. The lamp may be electrodeless and may in addition contain a buffer gas as a component of its filling. Alternatively, the lamp may have internal electrodes (13) and contain mercury (12) as a buffer gas. The lamp has favorable light generating properties, in particular a good color rendering, and in addition may have a very high luminous efficacy.