Abstract: To provide a strain relief in a base for an electric lamp, adapted for coction to an external electrical energy source by at least one connection cable (6a, 6b) extending through and into the base, the base (2) is formed with a strain relief arrangement which includes a resilient sleeve (11) having an inner wall surrounding the at least one connection cable and, within the base bottom portion (9, 9'), a sleeve reception structure (9a) positioned inwardly of the bottom of the base, which includes a sleeve reception bore (10a, 10b) receiving and surrounding the resilient sleeve (11a, 11b) and exerting circumferentially uniformly, radially inwardly directed forces on the resilient sleeve. This decreases the diameter of the sleeve so that the inner wall thereof engages, clamps and squeezes the deformable insulation of the at least one connection cable and, also, can interengage or interlock therewith. The bottom portion (9) and the top portion (7) of the base are snapped together.

Abstract: To prevent corrosion of molybdenum connecting pins or wires extending from elt-sealed ends of high-power lamps, the region immediately adjacent the exit points from the melt-sealed end are cooled by a cooling gas, for example air or an inert gas such as nitrogen. The cooling gas is applied by cooling ducts which are made of metal and, simultaneously, provide for electrical connection of electrical energy to the connecting leads. Cooling gas can be introduced either through terminal pins or rods into the tubular elements, or the tubular elements can be connected, as usual, to the part-solid terminal pins or rods and additional gas connections are passed through the base through the tubular elements to supply cooling gas.

Abstract: To provide for dimmer operation of a fluorescent lamp (L) with a minimum of circuit components, the d.c. output level at an output terminal (C1) of an energy supply source, such as a switched mode power supply (10, 10'), is controlled in accordance with the setting of a dimmer control (D). The voltage level at the output capacitor (C1) of the switched mode d.c. power supply furnishes supply voltage for an inverter (T1, T2) coupled to the discharge lamp. During lamp operation, a control unit (R) controls the level of the d.c. voltage supply for the inverter in accordance with the dimmer setting. This permits change of the brightness of the fluorescent lamp (L) in a range of from 5% to 100% of nominal value. Preferably, control of the supply voltage for the inverter is activated only upon occurrence of the ignition or arc-over phase, for example under control of a timing circuit (ZS), controlling a relay in the preheating circuit of the lamp.

Abstract: To ensure contact of axially bent-back current supply leads, extending over plate-like base terminals of an elongated fluorescent lamp, and ensure electrical connection between the bent-over or bent-back portions with socket terminal springs (9a, 9b), in spite of misalignment of the bases (3) at two opposite ends of the fluorescent lamp, the junctions or corners (1118) between the narrow wall portions (18a, 18b) and wide side wall portions (11a, 11b; 12a, 12b; 13a, 13b) of the end portion (4) of the base are set back from the position in a theoretical geometric rectangle or parallelogram to form relieved wide side wall portions. The relieved side wall portions extend axially over essentially the entire length of the end portion (4) of the base.

Abstract: A method for producing a metal-halide discharge lamp with a ceramic dische vessel is distinguished in that first both ends (6a, 6b) are equipped with electrode systems and sealed off, but a filling bore (15) remains in the vicinity of the pump end (6a) and is not closed until after the filling.

Abstract: To control the color temperature of a sodium high-pressure discharge lamp, preferably having a sodium and xenon fill, which may also include mercury, without essentially affecting the color rendition index of the emitted light, or the light flux or intensity of light radiation emitted, the lamp is operated under pulsed conditions, in which the instantaneous pulse power of recurring power pulses, separated by a holding phase to prevent extinction of the lamp, is controlled. Preferably, the overall energy of any one of said power pulses and the intervening holding pulse is maintained essentially constant, for example by varying the frequency of sub-pulses or oscillations of which the sequential power pulses are constituted. A frequency and power controllable oscillator (1) is connected to the lamp (3) through a series LC network to effect such control, thereby permitting adjustment of color temperature and matching of the light output to selective color reflectivity of illuminated objects.

Abstract: To provide for optimum control of a sodium high-pressure discharge lamp operating under saturated operating conditions, such that the lamp will be operating stably and providing light output which is an optimum with respect to the color rendition index (Ra), light output or luminous flux, and color temperature, without regard to manufacturing tolerances or variations in power supply voltage, the energy supplied to the lamp is controlled with respect to a quotient formed of lamp voltage and lamp current (V.sub.L /I.sub.L), said quotient being determined with respect to optimum light values. The power supply for the lamp (3) either is a stabilized output voltage power supply (22) in which the output current is controlled, or an oscillator (32) providing bursts or power pulses (10, 10') formed of oscillations (11).

Abstract: To prevent attack on electrodes (4, 5) within a discharge vessel (2) by an ionizable metal halide fill, due to spurious or free oxygen arising within the lamp during operation thereof, which oxygen combines with the metal of the electrodes, and is then dissociated in the arc and re-deposited at the hottest part of the electrode, an oxygen removing getter material is introduced into the discharge vessel. Spurious oxygen arises due to emission of oxygen from the glass wall of the discharge vessel, typically quartz glass, and unavoidable contaminants of the fill substance. The getter material is, preferably, phosphorus, boron or aluminum, a halide of the foregoing, a tungsten boron compound, a tin phosphorus compound, or scandium or a rare earth. If the getter is a halide, iodine, bromine or chloride are suitable. The getter may be introduced in quantities of between 0.05 to 0.6%, depending on the getter substances and the fill composition.

Abstract: To operate a low-pressure discharge lamp, typically a fluorescent lamp, from a low voltage source of, for example, between 5 and 24 V, two diodes (D1, D2) polarized to provide for current passage towards the lamp are connected between the output of a blocking oscillator and the lamp (L). At least one diode (D2) provides for preheating the lamp electrode. The other diode (D1) prevents immediate starting of the lamp; it is integrated in the circuit between the secondary winding (N2) of the blocking oscillator transformer (TR) and one lamp electrode (E1). The first diode (D2) is connected between the primary winding (N1) and the other terminal of the secondary winding (N2), and also to the other lamp electrode (E2). An additional capacitor (C4) connected, effectively, across the lamp (L) improves the starting of the lamp. The circuit is readily adaptable for association with a recharging circuit (FIG. 3) for recharging a rechargeable battery to supply the lamp.

Abstract: To provide a sealed through arrangement for electrical leads through a ceramic end plug, suitable for discharge lamps of between about 50 to 250 W power rating, the lead-through (9) is made of a material having a thermal coefficient of expansion which is substantially less than that of a ceramic sealing plug (10), for example of tungsten, molybdenum or rhenium, but so small that the individual, actual expansion of the ceramic material will not cause separation from the metal, and/or a glass melt, ceramic melt or sintar connection therewith. The electrical connection is formed by at least two, and preferably more than two, thin wires or pins (23) having a diameter, each, of up to only about 0.25 mm, and preferably less. Each of the wires, then, will carry currents in the tenths ampere ranges, sufficient for operation of the lamp, and passed through melt-sealed capillary openings in the ceramic sealing plug (10).

Abstract: To securely and reliably hold a high-voltage, for example service-line voge (110 V, 220 V) halogen incandescent lamp within an outer envelope (2), and forming an electrical connection terminal to a screw-in, or straight-wall tubular base sleeve (3a, 43a) of a standard base, for example of the E14 or of the B22d type, a punched sheet-metal element (5, 5', 5", 25, 48, 48') is clamped around a projecting end portion (1a, 20a, 41a, 41a') of the halogen incandescent lamp; the projecting end portion, preferably, is a pinch seal, and the punched sheet-metal element is formed with a lower part and an upper part, in which the upper part clamps around or against the pinch seal. The lower part is partly located within the base sleeve and mechanically, and preferably electrically secured thereto. The pinch seal, preferably, is formed with a transversely extending rib, and the clamping portion is formed with a matching locating notch to ensure axial retention of the halogen lamp in the base.

Abstract: To simply and reliably retain a heat retention tube or sleeve (10) within envelope (1) and surrounding the arc tube or discharge vessel (4) of the lamp, end regions of the heat retention or conservation tube are pinched around current supply leads (7) which pass through the pinch or press region (11). To prevent dislocation of the tube or sleeve (10), axially as well as rotationally with respect to the arc tube, the current supply leads are deformed in the region of the pinch or press (11), for example by being flattened or deflected in a bend or V-shape from a straight wire. An exhaust tube (12) can be passed through the pinch (11) if the pinch extends across the entire diameter of the heat retention tube; otherwise, the pinch need only extend over a portion thereof, thus providing for pneumatic communication between the interior of the heat retention tube and the envelope (1).

Abstract: To provide a tight seal between an essentially solid niobium or tantalum necting pin or rod (10) passing through an opening (7, 28) in an end plug (11) closing off a high-pressure discharge lamp discharge vessel (8), the pin or rod is formed with two axial portions, one of which has externally projecting continuous rings (17), preferably two or three, or an externally projecting thread (26). The rings or thread are press-fitted into the end portion of the bore in the plug, which deforms the edge (20) of the rim, ridge or thread, or shears off the edge portion, ensuring a tight preliminary fit in the bore; sealing glass, which is then melted to fill a capillary space between the pin or rod and the plug, is protected by the preliminary seal against corrosion or attack from the fill within the discharge lamp; if the projection is in form of a thread, glass can penetrate within the threads to further seal and retain the pin or rod.

Abstract: To facilitate manufacture and assembly of a high-pressure discharge lamp ing an inner discharge vessel (4) within an outer bulb (1), and which is protected against explosion or bursting of the discharge vessel by a protective sleeve or body (8), typically formed of two sleeves or tubes (8a, 8b) of quartz glass or hard glass, the two glass tubes surround the discharge vessel (4) over its entire coaxial length and, when coated with an infrared (IR) reflective coating and an ultraviolet (UV) radiation coating, additionally function as a heat retention or heat damming element and a UV radiation protective element. Two ceramic insulating centering and holding elements are carried by a lamp holder structure (9), engaging the open ends of the glass tubes (8a, 8a). The ceramic elements are formed with steps (20a, 20b, 20c) or grooves (520a, 520b) to position the glass tubes spaced from each other and concentric with respect to the discharge vessel.

Abstract: To facilitate manufacture of a high-pressure discharge lamp in which a double-ended discharge vessel is located within an outer, essentially rotation-symmetrical bulb (1), the holder structure for the discharge vessel is formed of first and second punched sheet-metal elements (12a, 12b; 20, 21) which define surface planes, and are electrically separate from each other. A first punched sheet-metal (12a, 20) is electrically connected to a first current supply lead (7a) from the discharge vessel and a first current connector (11a) extending from the base. A second punched sheet-metal element (12b, 21) is electrically connected to the second current supply lead (7b) and the second current connector (11b, 11b') extending from the base. Both punched sheet-metal elements are located essentially in a central plane, and extend essentially perpendicularly with respect to the lamp axis (I--I).

Abstract: To prevent bowing of the arc of a high-pressure discharge lamp operated horizontally, the lamp is supplied with alternating current of between 10 kHz and 100 kHz, in which the frequency and wave shape of the alternating current portions of the supply are so selected that standing radial acoustic resonances will be formed within the discharge medium or fill in the discharge vessel, which standing radially directed acoustic resonances suppress or counteract bending of the discharge arc due to convection phenomena.

Abstract: To protect the plastic material of a plastic base (2) holding a single-en high pressure discharge vessel (1) in position with respect to ultraviolet (UV) radiation and heat emitted from the discharge vessel in operation of the lamp, a cover element (7, 7") of UV radiation and high temperature resistant material, such as a ceramic and preferably aluminum oxide, is positioned between the discharge vessel and the plastic material of the base, located to shield the plastic base from UV and heat radiation. The cover element is, essentially, in disk or plate form, and irremovably connected to the base, for example by pin extensions integral with the base, passing through recessed openings in the cover element, and headed over, in the form of rivet or button heads, for example by ultrasonic welding.

Abstract: To protect a niobium tube (9) forming a current supply lead through a thrh-opening (14) in an end plug (10) in a ceramic discharge vessel against attack by halides or condensed sodium, the through-opening is formed in two portions, of different diameters. The outer portion (16), remote from the discharge vessel, has a diameter which is matched to the diameter of the tube (9), leaving only a capillary between the plug opening and the tube; the second, inner portion (17) is narrower than the first one, that is, outer portion, and surrounds the shaft of the electrode by a sufficient distance to permit expansion of the electrode, typically of tungsten, under operating conditions, without cracking the plug by forced engagement with the wall of the inner portion (17) of the aperture. A sealing glass, melt-sealed into the capillary of the outer portion, seals the niobium tube.

Abstract: To improve the operation of high-pressure discharge lamps by preventing pature deformation of the end face of an anode due to extremely high temperature, with subsequent vaporization of tungsten material from the electrode and deposition on the bulb or vessel of the high-pressure discharge lamp, the electrode is axially forged, for example by hammering, to compact and change the grain structure of the electrode towards a finer grain than elsewhere in the electrode and increase the hardness of the electrode across the end face surface. Both--higher density and finer grain structure--increase the parameters which characterize the lifetime of electrodes, and hence of the lamp, namely heat conductivity and resistance against deformation under heat stress.

Abstract: To permit operation of a high-pressure discharge lamp having a metal halide ill at temperatures higher than those acceptable by quartz glass bulbs, the discharge vessel is made of transparent ceramic, thus providing, in operation, better color rendition and higher light output. To eliminate the corrosive effects of attack by the halides on a lead-through connection, the lead-through is made of a solid rod, pin or wire of, preferably, niobium of between 0.5 to 1 mm diameter, passing through a sintered plug (10), in which the niobium lead-through is recessed into the bore from the plug, and the electrode shaft (12) is connected to the lead-through within the recess. The walls of the plugs surrounding the recess thus protect the niobium against corrosive attack, while maintaining the seal throughout its length. Thus, niobium which has a temperature coefficient of expansion close to that of the ceramic can be used.