Abstract: A metal halide lamp has a ceramic discharge vessel with two ends (5) which are closed off by sealing means which enclose a capillary tube (11). An electrically conductive lead-through (9) is passed in a vacuum-tight manner through a bore in the capillary tube (11). The capillary tube (11) comprises two sections (20, 21) which are arranged axially one behind the other, the diameter of the bore of the inner section amounting to at most 90% of the diameter of the bore in the outer section.

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 permit change of direction of light emitted from a reflector lamp (3) adapted to be secured in a fixed socket, a reflector unit, preferably in the form of an attachment, is provided which is formed by a frame (2) which pivotably retains a partially light transparent and partially light reflecting disk (1). The frame (2) is coupled by a snap connection with a circumferential rim (3a) of the reflector lamp, so that the disk (1) is rotatable about the reflector axis (A) as well as pivotable in the arms (2). The reflector axis (A) and the pivot axis (P) of the disk preferably are perpendicular to each other. The disk may have a mirror reflective, and one matte surface, and can be made of plastic, aluminum, sheet steel and, if so, formed with openings (1a) therethrough; if made of glass, the surface can be partially light reflective/transmissive.

Abstract: To close off tubular ends (6a, 6b) of a metal-halide discharge vessel, a plug (11) having at least four, and preferably six or more, axially arranged layers or strata (11a-11d; 21a-21f) of a cermet, in which the metal content of the cermet of the respective layers or strata increases from the layer or stratum closest to the discharge space of the vessel to the outside. The innermost layer or stratum is directly sintered to the ceramic discharge vessel, typically of aluminum oxide, whereas the outermost layer or stratum has a metal content of such an extent that it can be welded, and is welded, to a metallic or cermet lead-through or feed-through (9, 20, 30, 35) leading through a central opening in the respective layers or strata of the plug. The outermost layer of the plug, preferably, has at least 50%, by volume, of metal, preferably of the same material as that of the lead-through in the cermet, and may even be made entirely of metal, to ensure a tight, easily made weld connection.

Abstract: At least at one end of a discharge lamp, for example a metal-halide discharge lamp or a sodium high-pressure discharge lamp, which has a ceramic discharge vessel (4), a feed-through (9, 10; 30) is provided which includes a cermet. The cermet may be in pin or capillary tube form, and has a metal content which is so high that it can be welded like a metal. The cermet can be directly sintered into an end plug (26) or into an end portion (34a, 34b) of the vessel itself. The seal thus is effected by a sealing arrangement (11, 21, 34a, 34b, 31) devoid of glass melt, which would be degraded by attack of corrosive fills within the lamp, while additionally having the capability of withstanding higher operating temperatures.

Abstract: The electrode of tungsten material has a cylindrical shaft and a conical tip, in which the conical tip is made essentially by radial deformation, such as hammering or cross-rolling, of the tip portion (9) of the electrode blank (5). This changes the grain structure to be converging. A flat top or plateau (10) can be ground at the very end of the tip.

Abstract: To eliminate the necessity of a separate base for a pinch-sealed lamp having a glass bulb, a sleeve (11) made of the same material as the bulb (1) of the lamp, is formed on an extension of the pinch seal (6), the sleeve retaining a contact element (13) secured in the sleeve, for example by molten glass. The contact element (13) extends essentially transverse to a longitudinal axis (A) of the lamp, is recessed within the interior of the sleeve (11) and preferably has a circumference, which is spaced from said axis (A) by circumferentially different distances, optionally in accordance with a mathematical function which, further optionally, is a periodic function, wherein the minimum spacing of the circumference of said contact element from the axis (A) is less than the inner radius of the sleeve (11).

Abstract: To provide a halogen incandescent bulb with controlled variation in wall ckness of the bulb, a bulb tube (20) first has a cup region (26) formed thereon. The cup region, by radial application of force, for example by rollers (22), is constricted, and the constriction then pulled to form a small, closed projecting tip (19). Mold jaws (27) then mold the shape of the bulb; the mold jaws are formed with a cavity (29') to receive the projecting tip (19) which, then, has the end cut off to provide an attachment cannula (30) for the pumping tube (32). The pumping tube is melted on the nipple (29) of the cup (26) of the bulb. A filament mount (8) with filaments (9) is then introduced, and pinch jaws (35) pinch-seal the filament mount in the bulb and finish-shape the bulb. The bulb can then be flushed, evacuated, and filled with the requisite halogen containing fill through the pumping tube (32), which then is tipped off.

Abstract: Start and operation of high pressure discharge lamps, in which a high-frequency starting voltage U.sub.HF and an operating voltage U.sub.B are furnished to the lamp electrodes includes the steps of: 1) turning on the high-frequency starting voltage U.sub.HF at a starting time t.sub.0 to ionize the lamp filling and preheat the electrodes; 2) turning on the operating voltage U.sub.B after a preheating interval .DELTA.t.sub.H, that is, at time t.sub.1 =t.sub.0 +.DELTA.t.sub.H ; and 3) turning off the starting voltage U.sub.HF at time t.sub.2 .gtoreq.t.sub.1, as a result of which the lamp is then operated solely by means of the operating voltage U.sub.B. As a result, the transfer phase for the development of the arc is shortened. Advantageously, the frequency of the starting voltage is selected such that the product of the frequency f of the starting voltage U.sub.HF and the spacing d between the electrodes meets the condition f.multidot.d.gtoreq.50 kHz.multidot.cm.

Abstract: To inhibit, or at least sharply attenuate, fluorescence of a quartz-glass velope (10) surrounding a light source (11), such as a halogen incandescent lamp, a high-pressure discharge lamp, or the like, when the quartz glass is subjected to ultraviolet (UV) radiation from the light source, and has been doped with a UV radiation absorbing material, typically a cerium, or cerium-titanium doping, the quartz-glass envelope is additionally doped with barium and boron. The barium/boron in the doping is, preferably, present in quantities of between about 0.008 and 1.25%, by weight, with reference to the undoped quartz glass. Barium metaborate can be used, optionally together with praseodymium to attenuate the fluorescence. Preferably, barium and boron form a combined doping substance with cerium, in form of a cerium aluminate and metaborate, added to the starting material for the quartz glass, and before the quartz glass is fused from quartz sand or pulverized quartz crystal.

Abstract: To largely, or entirely inhibit glow discharges during the start-up or run-on phase (Ta) of a high-pressure discharge lamp, the lamp is operated in a second time period (T2) immediately after ignition (T1) with continuous direct current during which the electrode of the lamp which then functions as an anode has reached emission temperature; in a third time period (T3), the polarity of the direct current is reversed and the other electrode, which now will function as an anode, is heated to emission temperature; thereafter, alternating current energy is supplied to both electrodes, typically in frequencies between 90 and 150 Hz. A suitable second time period (T2) can be about 2 to 21/2 second, the third time period (T3) being shorter. The total warm-up time may extend to a minute or more; current being supplied during the second, third and subsequent periods is usually higher, for example by a factor of 1.5 of the normal or rated operating current.

Abstract: To provide for reliable interconnection of a cover (4) with the body (1) of socket and socket housing for an electric lamp which, also, is formed with a receptacle or socket to receive the base of the lamp, preferably a compact fluorescent lamp, a rotary interengaging screw-type connection is provided between the cover and the body. To prevent inadvertent removal, an interengaging snap connection (6, 8) is formed on the cover (4) and on the body, respectively. The snap connection (6, 8) engages upon assembly of the cover (4) with the body (1). To remove the cover (4), a tool such as a screwdriver is engaged through a small slit (16) in the body, to deflect a resilient flap formed by the cover element. A positioning rib (14) is provided within the body to secure the resilient flap in deflected position, even after removal of the tool, to permit easy disassembly of the cover (4) from the body (1) without requiring continued deflection pressure on the resilient flap.

Abstract: To effectively suppress glow discharge of a discharge lamp, especially a h-pressure discharge lamp, immediately after starting or firing, the lamp is supplied in a second, or run-on phase with a run-up current which has a form factor F greater than one (1), for example 1.13 to 1.45, and which has an effective value I.sub.eff which is higher than the rated normal operating current of the lamp. A control circuit (C), coupled to a controllable power supply, and to a switchable bridge circuit, controls the frequency of the run-on phase current to be higher than the normal operating frequency, for example about 2 kHz with a normal operating frequency between about 90-150 Hz.

Abstract: To provide for effective control of a discharge lamp, typically, a sodium gh pressure discharge lamp, which operates in two phases, namely, a power pulse phase, followed by a holding phase, without extensive and complex electronic circuitry, two individual oscillator systems are provided, one for each phase; the oscillator systems include a first power burst oscillator formed as a first half bridge by two transistors (T1, T2), and an individual connecting current limiting inductance (L1) to the lamp (E), and a second oscillator including a two-transistor second half bridge (T3, T4) and an individual current limiting inductance (L2) coupled to the lamp. The respective oscillators are controlled, in a closed control loop, by a burst generator (BG) and a holding pulse generator (SG), each of which provide their signals to a logic circuit (LK) which provides for exclusive control of the respective first or second half bridge.

Abstract: To insure that lamps which have a non-rotation symmetrical feature or strure with respect to aligned bases (e.g., a tipped-off exhaust or pumping stub) are placed in a predetermined preferred operating position when inserted into socket terminals (2a, 2b), the lamp bases are formed with stepped surface abnormalities (10a, 10b), for example, in the form of recesses or projections from a terminal engagement surface (8a, 8b) extending perpendicularly to the lamp axis (A--A); socket springs (2a, 2b) have matching surface abnormalities which interengage with the surface abnormality on the base, for example by being formed with ridges, or depressions. The lamp thus can be inserted in such bases only if the respective surface abnormalities on the lamp bases and in the socket terminals can engage.

Abstract: To provide for automatic switch-over between a power phase and a holding se in operation of a discharge lamp (EL), a choke or ballast coil (L), serially connected to the discharge lamp, is constructed to have, with respect to current flow therethrough, a non-linear reactance value; the choke or ballast coil is wound on a core which, for example, can be a E-core in which the center leg is of reduced cross-section with respect to the outer legs; or, if one is a torroidal coil on a ring core, the ring core is preferably made of two core elements of different magnetic characteristics, connected together, for example by an adhesive, in which one core element is of low permeability material, such as iron powder or permaloy with high saturation magnetization, and a second core is formed of ferrite with low saturation magnetization.

Abstract: The invention relates to a high-pressure discharge lamp with an outer bulb urrounding the discharge vessel, and to a process for producing a high-pressure discharge lamp. The outer bulb (1) comprises a glass that has a low viscosity and in particular a lower softening temperature than the quartz glass of the discharge vessel (2), and is melted directly onto the ends (5a, 5b) of the discharge vessel (2), which is sealed on both ends. As the glass for the outer bulb, a quartz glass doped with viscosity-lowering additives, in particular alkaline-earth metal borates, is used, while the discharge vessel comprises undoped quartz glass. In addition, the quartz glass of the outer bulb is preferably doped with rare earth metal additives that absorb UV radiation.

Abstract: To provide for improved light distribution of a vehicular headlight furning both depressed-beam and high-beam illumination, a shadow cap (9, 25) partly surrounds a main light source, typically filaments of halogen incandescent lamp, located in a reflector (2) which has two segments (14, 15) of different contours. The first one (14) of the reflector segments is optically associated with the main filament furnishing depressed-beam illumination, and this segment has a free-formed surface reflection contour. A second segment of the reflector is optically associated with an auxiliary filament (8, 18). The shadow cap (9, 25) provides a shadow angle of between 100.degree. and 140.degree. with respect to light emitted from the main filament (7) to define a shadow zone (12) and a light zone (13) on the reflector. The shadow cap is shaped and positioned with respect to the auxiliary filament (8, 18) such that the auxiliary filament is located within the shadow zone (12).

Abstract: To substantially reduce harmonic distortion and improve the power factor of n operating circuit for a fluorescent lamp, a smoothing circuit (G) is interposed between the outputs from a power rectifier (GL) and an inverter (WR) supplying the fluorescent lamp (L) with high-frequency energy. The smoothing circuit includes a two electrolytic capacitor (C1, C2)--three diode (D1, D2, D3) network, which is so connected, and the diodes so polarized that, during charging of the capacitors, a series circuit is established with one (D2) of the three diodes in series with the two capacitors. For discharge of the capacitors to supply the inverter when the rectified voltage is lower than the capacitor voltage, the two capacitors (C1, C2), through the other two diodes (D1, D3), are connected in parallel to supply the inverter. To substantially reduce harmonic distortion to less than about 30% and improve the power factor of the circuit to above 0.

Abstract: A xenon excimer (Xe.sub.2) radiation source for producing vacuum ultraviolet (VUV), broad-band, molecular radiation of wavelengths shorter than 200 nm includes fluorescent materials for excitation by the VUV radiation and illumination purposes. The fluorescent materials include a mixed borate with the general formula: (Y.sub.x Gd.sub.y Eu.sub.z)BO.sub.3 ; a mixed aluminate with the general formula: (B.sub.a Eu.sub.y)MgAl.sub.10 O.sub.17 ; a mixed aluminate with the general formula: (Y.sub.x Gd.sub.y Eu.sub.z).sub.3 Al.sub.5 O.sub.12 ; a mixed silicate with the general formula: (Y.sub.x Sc.sub.y Tb.sub.z).sub.2 SiO.sub.5 ; a mixed borate with the general formula: (Y.sub.x Gd.sub.y Tb.sub.z)BO.sub.3 ; and a mixed phosphate with the general formula: (Ln.sub.x Ce.sub.y Sc.sub.w Tb.sub.z)PO.sub.3.