Abstract: The high pressure lamp has a bulb (2) to which a neck (4, 4a, 4b) is joined. The transition region (6) between the bulb and the neck is conical. A support tube (5, 20, 25) surrounds a holding rod (10) for an electrode (11) within the bulb. The support tube is melt-connected to the neck, and conical with an inner end of the support tube having an outer diameter which is smaller than the outer diameter of the outer end of the support tube. The neck, likewise, is conical, and forms a transition region to the bulb, which is free from the support tube, so that the support tube is recessed within the transition region. This recess is between 3 and 25 mm and corresponds, at the most, to twice the outer diameter of the support tube at its inner end. The ratio of the outer diameter of the outer, or remote, end of the support tube (5, 20, 25) and the outer diameter of the inner, or proximate, end of the support tube is between 1.1 and 2.5.

Abstract: To eliminate radiation from the mercury high-pressure discharge lamp of wlengths below 365 nm, the lamp includes a discharge vessel of quartz glass which is doped with vanadium in a quantity of up to about only 250 ppm, by weight, with respect to 1 mm of wall thickness of the quartz glass. This absorbed radiation also heats the quartz glass, so that the outside wall temperature of the vessel can be maintained between about 400.degree. and 950.degree. C. The effect can be enhanced by adding, additionally, titanium and/or tin to provide metal ions to the doping substance, in an overall quantity of up to 500 ppm, by weight. Alternatively, the quartz glass can be coated with TiO.sub.2 or SnO.sub.2. Suitable wall thicknesses for the discharge vessel are between 1 and 5 mm, and the fill therein is preferably mercury in a quantity of between 0.5 and 15 mg/cm.sup.3 and xenon with a cold fill pressure of 0.1 to 2.5 bar. Electrode spacing of the lamp is preferably between 2 and 5 mm.

Abstract: To essentially eliminate short ultraviolet (UV) radiation from a mercury high-pressure short-arc discharge lamp, that is, wavelengths below the radiation band of 365 nm, the lamp includes a discharge vessel of quartz glass which is coated with a selectively reflective outer coating (2a) and, at the inside, with a selectively absorbing inner coating (2b). The outer coating (2a) is formed by a multi-layer interference reflection filter which preferentially reflects wavelengths between about 240 and 300 nm with a filter cut-off, corresponding to 50% transmission, in the wavelength region between about 290 and 330 nm. The inner coating (2b) is a titanium dioxide coating which, preferentially, absorbs radiation below about 250 nm, with a 50% transmission at about 240 nm. In accordance with a preferred feature of the invention, a radiation absorbing titanium dioxide/silicon dioxide mixed-layer coating (2c) is applied at the outside over the multi-layer interference reflection filter (2a).

Abstract: To permit high lamp currents to be applied to lamp electrodes (5, 6) of a discharge vessel (2) from which two elongated necks (3, 4) extend via current supply leads (23, 35), the discharge vessel is first made as a generally rotation-symmetrical element, to which tubular cylindrical neck tubes (17) are sealed. A cylindrical plug element (26, 40) is placed in the neck tube adjacent the discharge vessel. A subassembly is then made of a core element, which can be constructed as a single or a composite structure of quartz glass, for example by telescopically fitting quartz glass tubes over a central core, and melt-sealing the tubes and core together. Molybdenum disks (7, 8; 22) are placed against the end faces of the core element, and a plurality, for example four, molybdenum connecting foils (11-16, 27) are secured to the circumferences of the disks, to axially connect them together.