Abstract: The invention relates to circuitry for the operation of a high-pressure dharge lamp including a voltage transformer (T1, T2), preferably a push-pull transformer, a transformer (TR1) connected to the output of the voltage transformer (T1, T2), a pulse ignition device, and a load circuit designed as a ocrial resonance circuit (L1, C1) into which the high-pressure discharge lamp (LP) is switched. The transformer (TR1) possesses at least two secondary windings (w1c, w1d), wherein the first secondary winding (w1c) switches into the load circuit and the second secondary winding (w1d) is connected to the pulse ignition device at the voltage input. The ignition voltage output of the pulse ignition device is designed to be connected to an auxiliary ignition electrode (ZE) of the high-pressure discharge lamp (LP).

Abstract: Ultraviolet (UV) radiation in the UV-C and UV-B bands, which is particularly dangerous, is absorbed and filtered by quartz glass doped with between 0.065% and 3.25%, and preferably between 0.065% and 1.3% by weight, of cerium metal, or cerium as such. Preferably, the cerium is added to quartz sand and/or rock crystal, in form of a fine-grained powder of up to 2 0 .mu.m grain size, in form of cerium aluminate (CeAlO.sub.3), present in up to about 5% by weight, and preferably up to about 2%, and melted together in a single step. The quartz glass so obtained is particularly suitable for a metal halide discharge lamp, e.g. as an outer envelope (1), or as the discharge vessel (27) itself, or for halogen incandescent lamps, to form the quartz-glass light bulb or an envelope therefor. A small quantity of titanium oxide, up to about 0.05%, may be added as a further doping agent to the melt to further improve the UV absorption in the B and C bands.

Abstract: To be able to accept high-voltage pulses, in the order of 70 kV, required r re-starting a hot high-power high-pressure discharge lamp, having a power rating, for example, of 6 kW and up, including 12 kW, a ceramic base is provided with auxiliary mica strips or plates (13) positioned between part of the terminal posts or pins, and especially in the region of retentions flanges or rims formed thereon, and extending up to about the end portion (4a) of a pinch or press seal, into which connection leads extend, connected to the pins or posts. The additional mica strips or plates (13), for example located on both sides of a central separating strip (10), retained in suitable grooves or slots (14) formed in the base effectively prevent arc-over, creep currents and corona discharge between the terminal pins or posts (8a, 8b), the circumferentially projecting flanges or rims (16a, 16b) and the connected current supply leads (7a, 7b).

Abstract: Ultraviolet (UV) radiation in the UV-C and UV-B bands, which is particularly dangerous, is absorbed and filtered by quartz glass doped with between 0.065% and 3.25%, and preferably between 0.065% and 1.3%, by weight, of cerium metal, or cerium as such. Preferably, the cerium is added to quartz sand and/or rock crystal, in form of a fine-grained powder of up to 20 .mu.m grain size, in form of cerium aluminate (CeAlO.sub.3), present in up to about 5% by weight, and preferably up to about 2%, by weight, and melted together in a single step. The quartz glass so obtained is particularly suitable for a metal halide discharge lamp, e.g. as an outer envelope (1), or as the discharge vessel (27) itself, or for halogen incandescent lamps, to form the quartz-glass light bulb or an envelope therefor. A small quantity of titanium oxide, up to about 0.05%, may be added as a further doping agent to the melt to further improve the UV absorption in the B and C bands.

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.

Abstract: To provide a high-pressure lamp capable of carrying lamp currents of 100 eres and higher, an essentially rotation-symmetrical discharge space (2) has two cylindrical necks (3, 4) melt-sealed thereto. Each one of the necks is formed of at least two telescoped hollow cylindrical quartz glass tubes (19, 27) which, with sealing foils circumferentially located within the neck, are all gas-tightly melt-sealed together. The sealing foils, typically of molybdenum, are electrically connected to a molybdenum disk (7, 8), for example by being welded to the circumference thereof which, in turn, is soldered to an end portion of an electrode shaft (5, 6), typically of tungsten, which extends into the discharge space of the discharge vessel.

Abstract: To reliably support a metal halide discharge vessel within an outer bulb, spite of possible shock or vibration, and to accomodate thermal expansion in use, a support structure (6) is provided, melt-connected to the base (4) and having a cross bar portion (15) positioned transversely to the lamp axis of a length substantially less than the diameter of the outer bulb (1), and electrically and mechanically connected to one of the current supply leads (11) of the discharge vessel. The cross bar portion is connected through respectively inclined connecting portions (16, 17; 16', 17') to transversely extending first and second holding portions (20, 21; 20', 21') located within the outer bulb, and extending in chord across the outer bulb at respectively opposite sides of the discharge vessel.

Abstract: To provide for reliable connection of electrical terminal contact elements (5, 5', 5") within a socket body (2) and remove stresses such as tension, pressure, or torsion applied by a connecting cable (9), the contact terminal elements (5) are formed with a plate-like projection, extending essentially parallel to the contact elements, and secured in grooves or slots (12) formed in the inner walls of the body of the socket, or between projecting ribs (21) extending from the contact terminal chamber walls (7).

Abstract: To prevent the formation of melt-back slugs or granules on electrodes of h pressure, high power discharge lamps, when the lamps are operated under alternating current conditions of between about 20 to 60 A, for example, the electrodes are terminated in regions of decreasing diameter and, in accordance with the invention, comprise tungsten doped with lanthanum oxide (La.sub.2 O.sub.3) between about 0.5 to 2%, by weight, preferably about 1%. The doping intensity may increase towards the inside region of the electrode.

Abstract: To increase the power output of a high-pressure metal halide discharge lamp aving a fill of mercury and at least one noble gas, and rare-earth halides which include at least one of: holmium; dysprosium, preferably present, each, of from 0.01 to 2.4 mg/cm.sup.3 of the discharge vessel, a gadolinium halide, present of from 0.01 to 2.3 mg/cm.sup.3 of the discharge vessel is additionally included in the fill. The discharge vessel is made of quartz, the electrodes of tungsten, and, in an example, a lamp operating at 12 kW, with 380 V power supply at 65 A is obtainable, the light output being comparable to that of daylight based on CIE standard D 60, with a color temperature of 6000.degree. K. so that an overall color temperature of about 5600.degree. K. is obtainable when the lamp is installed in a customary fixture, for example used in theatrical, film or television illumination application.