Abstract: A vapor discharge lamp comprised of an arc tube containing an ionizable medium, a first electrode electrically connected to a first in lead conductor, and a second electrode electrically connected to a second in lead conductor, said first and said second electrode pairs being positioned to create an arc discharge therebetween, an electron emissive material disposed on at least one of said electrodes, said electron emissive material being Ba.sub.4 Al.sub.2 O.sub.7.

Abstract: A three-phase high-pressure gas discharge lamp comprising a discharge vessel (1) made of a translucent heat-resistant material. Three electrodes are arranged in the discharge vessel (1), each being fed from a separate phase of a three-phase supply system, each electrode including an electrode tip (7), an electrode stem (5) and an electrode head (6). The electrodes are arrnaged so that their electrode tips (7) occupy the vertices of an equilateral triangle fully enclosed in the discharge vessel (1). The discharge vessel (1) contains a filling consisting of a noble gas, mercury and a further additive selected from the group consisting of preferably sodium and a metal-halide.

Abstract: The invention relates to a metal-halogen discharge lamp with an alkali-halide additive. The lamp consists of the discharge tube (2), the outer bulb (1), the current leads (3) led into the discharge tube (2) through the outer bulb (1). The discharge lamp according to the invention can be characterized in that the metal components arranged in the outer bulb of the discharge lamp and connected electrically to the mains are separated by a material insulating against alkali ions or alkali ions and electrons.