Abstract: The high-pressure electric discharge tube of the invention can operate in the open air, with at least 10 Hg mm inner pressure. It has a preferably ceramic (or crystalline) envelope that constitutes an illuminator, with electrodes disposed in two opposite portions of the envelope, appropriate inlets, lead-ins and terminals leading to the electrodes. The discharge tube does not have to be surrounded by the hitherto applied, conventional, glass or other transparent protective envelope, as a result of which the emitted luminous output is free from reflections and the tube can be used throughout the entire spectrum, such as for pumping or driving a laser crystal. The protective envelope, which so far has been an indispensable part of all high-pressure discharge tubes, has been eliminated as a result of the present invention. Adapter tubes are used that prevent oxidation of the electrical elements, as well as specially configured electrodes.

Abstract: A high-pressure gas discharge light source with high light conversion efficiency and color rendering, having a translucent discharge vessel of high melting point material in which electrodes of high melting point material are suspended and containing a filling of an inert gas or a mixture of inert gases, at least one metal halide and optionally one or more metals in the elemental state under cold conditions, wherein the ratio of the metal to the halogen forming the halide is stoichiometric or greater, and the specific wall load factor is between 25 and 200 W/cm.sup.2 and/or the quantity of the halide or halides is 0.01 to 1 mg per centimeter length of the arc.