Abstract: A gas-discharge lamp (1) is described having an inner envelope (2) comprising a discharge vessel (3) and two tubular sections (6, 7) arranged on the discharge vessel, having two electrodes (4, 5) that project from the tubular sections (6, 7) into the discharge vessel (3) and that, to enable them to be supplied with power, are electrically connected to respective electrical conductors (10, 11) that extend through the associated tubular sections (6, 7) and that are enclosed in the tubular sections (6, 7) with a gastight seal along a sealing section (8, 9). The lamp (1) has an outer envelope (18) that is connected at each of its ends to respective ones of the tubular sections (6, 7) of the inner envelope (2) and that surrounds the discharge vessel (3) while leaving an outer cavity (20) between itself (18) and the discharge vessel (3).

Abstract: A gas-discharge lamp (1) is described having an inner envelope (2) comprising a discharge vessel (3) and two tubular sections (6, 7) arranged on the discharge vessel (3), having two electrodes (4, 5) that project from the tubular sections into the discharge vessel (3) and that, to enable them to be supplied with power, are electrically connected to respective electrical conductors (10, 11) that extend through their associated tubular sections (6, 7) and that are enclosed in the tubular sections (6, 7) with a gastight seal along a sealing section (8, 9) and having an outer envelope (18) that surrounds the discharge vessel (3), with an airtight seal, while leaving an outer cavity (20) between itself and the discharge vessel (3) and that is filled with a gas at a pressure of not more than 1,000 mbar.

Abstract: A gas-discharge lamp (1) is described having an inner envelope (2) comprising a discharge vessel (3) and two tubular sections (6, 7) arranged on the discharge vessel, having two electrodes (4, 5) that project from the tubular sections (6, 7) into the discharge vessel (3) and that, to enable them to be supplied with power, are electrically connected to respective electrical conductors (10, 11) that extend through the associated tubular sections (6, 7) and that are enclosed in the tubular sections (6, 7) with a gastight seal along a sealing section (8, 9). The lamp (1) has an outer envelope (18) that is connected at each of its ends to respective ones of the tubular sections (6, 7) of the inner envelope (2) and that surrounds the discharge vessel (3) while leaving an outer cavity (20) between itself (18) and the discharge vessel (3).

Abstract: A high-pressure discharge lamp (1) comprising at least one burner (2) having a discharge space, and comprising two electrodes extending in said discharge space, a gas filling in the discharge space containing at least an inert gas and a suitable metal halide mixture, and comprising an outer bulb (3) which is attached to the burner (2) and the basic material of which is doped with an absorbing material, the high-pressure discharge lamp (1) comprising at least one interference filter (6) which reflects predominantly in the wavelength range of 400 to 550 nm, and which is arranged directly on at least a part of the outer surface of the outer bulb (3), and the outer bulb (3) being doped with a material that is absorbing for wavelengths <550 nm.

Abstract: A lamp has a metal layer to prevent light escaping in an undesired direction. A sealed envelope wall encloses an interior space in which an electrical element is arranged. The wall is partly coated by the metal layer, preferably at a lamp end opposite a lamp cap. A light diffusing or absorbing layer over a side of the metal layer facing the interior space prevents light reflection back into the interior space. For use as a vehicle headlamp, the metal layer may be silvery as viewed from the outside so that it is not noticeable.

Abstract: The capped high-pressure discharge lamp suitable for use in a vehicle headlight has a discharge vessel which is surrounded by an outer envelope. Current conductors extend from a respective electrode to a respective contact at a cap in which a first neck-shaped portion of the discharge vessel is secured. A return portion of one current conductor extends along an outside surface of the outer envelope. The outer envelope has a light-absorbing coating in a region near the first neck-shaped portion, at a side which is remote from the return portion. The outer envelope may have band-shaped coatings at either side, aside from the discharge path between the electrodes, at its side which faces the return portion. Stray light in the beam formed by the reflector and the lens of a head-light in which the lamp is used, is obviated. The bands provide for a rectilinear light/dark transition in said beam.

Abstract: The electric lamp has a quartz glass lamp vessel (10) in which an electric element (3, 4) is accommodated. The lamp vessel locally has a light-absorbing, non reflective coating (11, 12). The coating mainly consists of 2 to 10% by weight of glass which is free of lead oxide and has a softening point between 600.degree. and 700.degree. C. Iron 50 to 60% by weight, primarily in metallic form, and manganese oxide, 30 to 55% by weight, are dispersed therein.