Abstract: Metal halide lamp for color applications for high wall loading with a long service life of at least 1500 hours and with a color temperature of over 5000 K: fill comprising at least the following constituents: firing gas, mercury, halogen, as well as indium, thallium, tin, no rare earth element or Na; the fill furthermore contains, as lithium replacement, hafnium, zirconium and tantalum, individually or in combination, the wall loading of the discharge vessel being at least 50 W/cm2; specific output based on die arc length is 50 to 90 W/mm; in particular, the concentration of the metals is as follows: lithium replacements: 0.20-4.0 &mgr;mol/ml; indium 0.3-3.0 &mgr;mol/ml.

Abstract: A metal halide discharge lamp having a bulb which contains a fill including an ignition gas, mercury, a halogen, lithium, indium, thallium and tin, and which is devoid of a rare earth element. Such fill serves to lengthen the service life of the lamp. The lamp is especially suitable for effect lighting.

Abstract: The metal-halide direct-current short-arc discharge lamp has a bulb (10) ch is asymmetrical with respect to a plane (1) perpendicular to a longitudinal axis (2) of the lamp, the bulb having an inner wall which is wider in the region surrounding the anode (4) of the lamp than in the region surrounding the cathode (5). Preferably, the lamp retains a fill system which includes cadmium and/or zinc. The lamp is particularly suitable for use in combination with an optical projection system (R), and especially when operating in horizontal position.

Abstract: The metal-halide direct-current arc discharge lamp has a fill system which as cadmium and/or zinc as components of the central fill in addition to an ignition gas, mercury, and a halogen. Preferably, the fill is retained in a bulb (10) which is asymmetrical with respect to a central plane (1) perpendicular to a longitudinal axis (2) of the lamp. The lamp is particularly suitable for use in combination with an optical projection system (R), especially when operating in horizontal position.

Abstract: A metal-halide high-pressure discharge lamp (1) with a discharge vessel (2) nd two electrodes (4, 5) has inside discharge vessel (2) an ionizable filling, which contains yttrium (Y) in addition to inert gas, mercury, halogen, thallium (Tl), hafnium (Hf), whereby hafnium can be replaced wholly or partially by zirconium (Zr), dysprosium (Dy) and/or gadolinium (Gd) as well as, optionally, cesium (Cs). Preferably, the previously conventional quantity of the rare-earth metal is partially replaced by a molar equivalent quantity of yttrium. With this filling system, a relatively small tendency toward devitrification is obtained even with high specific arc powers of more than 120 W per mm of arc length or with high wall loads. Thus, the filling quantity of cesium can be clearly reduced relative to a comparable filling without yttrium, whereby an increase in the light flux and particularly in the brightness can be achieved.

Abstract: A projection lamp includes a metal halide discharge lamp (1) with a lightansparent discharge vessel (2) in which two electrodes (3) stand opposite one another, which are joined with current leads (5) led to the outside, whereby the discharge vessel contains an ionizable filling including mercury, at least one noble gas, at least one halogen, one rare-earth metal (RE) as well as another metal, niobium, for the formation of metal halides. The addition of metallic niobium provides the lamp with good color reproduction and good arc stability.

Abstract: A high-pressure metal halide lamp which is particularly suitable for inclon in optical systems is run at specific power between 100 and 180 W per mm arc length. The lamp includes, per cm.sup.3 chamber volume, between 0.3 and 3 .mu.mol dysprosium, hafnium and lithium respectively and between 0.2 and 2 .mu.mol indium, whereby luminance of between 25 and 75 kcd/cm.sup.2 can be generated at color temperature of between 4500 and 7000 K. Light spots with a diameter of about 4 mm and a color reproduction index Ra of 80 are achieved by means of a special reflector. This makes it possible to use the lamp in combination with thin glass-fiber bunches for illumination purpose, e.g. in endoscopy.

Abstract: A high-pressure metal-halide discharge lamp (1) having a mean arc power been 60 and 140 W/mm arc length includes a discharge vessel (2), two electrodes (5,6), a fill of mercury, at least one noble gas, at least one halogen, cesium, and tantalum and dysprosium for forming metal halides to produce light with a color temperature between 400 and 700 K at a wall load of between 40 and 85 W/cm.sup.2 wall area. The tantalum maintains the halogen cycle process at relatively low wall loads, and thus prevents blackening and devitrification of the bulb, while dysprosium provides a high radiation flux in the visible range of the optical spectrum and thus optimizes color reproduction. At a wall load of between 40 and 85 W/cm.sup.2, optimum results are attained if the fill contains from 0.2 to 1.5 mg of tantalum and dysprosium per cm.sup.3 of vessel volume, in a weight ratio of tantalum to dysprosium of between 0.3 and 1.5. As a result, lamp service life of 1500 hours at a color temperature of 5500 K are attained.

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: 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 reduce the noise level of operation of a high-pressure metal halide diarge lamp, the lamp has a rotation-symmetrical discharge vessel (2) which has an inner surface which has a central region which is circular cylindrical and two facing transition regions (12, 13) which are straight-sided right-circular-conical and connect the central circular cylindrical region to extending shaft portions (3, 4) into which the electrodes and connecting foils are sealed. A lamp of this type, when operated from a square-wave power supply has a reduced noise level, particularly in the audio frequency range of between 6 to 20 kHz. A suitable angle between the circular cylindrical portion and the right-conical portion is between 120.degree. and 160.degree., for example about 145.degree..

Abstract: To generate light output from a metal halide discharge lamp having a fill which includes mercury, at least one noble gas, cesium and a metal halide, such that the color temperature will be between 4000 and 9000 K., and the color rendering index Ra is greater than 90, while, for the red spectral range, the color rendering index R.sub.9 is at least 50, the metal of the metal halides comprises hafnium, preferably present between 0.02 to 6 mg, or zirconium, preferably present between 0.01 to 4 mg, each per milliliter of volume of the discharge vessel (2, 14, 28). Both hafnium and zirconium may also be added.

Abstract: To maintain a predetermined design color temperature throughout the lifet of a metal halide high-pressure discharge lamp, particularly suitable for illumination of theaters, film or television studios, the discharge vessel of the high-pressure lamp, typically made of quartz glass, contains a fill which, besides mercury, has a noble gas, cesium and dysprosium halide and a nickel halide. Optionally, gadolinium halide may be used. Per cubic centimeter of volume of the discharge vessel, 0.03 to 3 mg dysprosium, 0.002 to 0.5 mg nickel, and, optionally, 0.002 to 0.1 mg gadolinium are suitable. Suitable halogens for the halides are iodine and bromium, preferably in a mol relationship between 0.2 and 1.5. The metals, nickel and gadolinium limit the color temperature drop-off over the average lifetime of the lamp to at the most 1 K per operating hour of the lamp.

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.