Abstract: An excimer lamp utilizing a high pressure fill. The fill includes a halogen at an operating pressure of greater than about 350 torr or the combination of a halogen and a rare gas at a total operating pressure of greater than about 2.5 atmospheres.

Abstract: Ignition of an electrodeless lamp, energized by microwave or radio frequency energy, is achieved by disposing an additive material in the lamp envelope along with the primary fill material. In a first embodiment, the additive is at least partially electrically conductive at room temperatures but non-conductive or a vapor at lamp operating temperatures. The preferred additives for this embodiment are mercury sulfide and mercury selenide. In a second embodiment, the additive is a material, such as piezoelectric crystals, that produces sparks in the envelope when the crystals collide with each other, or with other materials, in response to agitation of the envelope. The additive may alternatively build up electrostatic charge by rubbing along the interior surface of the lamp envelope when the envelope is agitated, the charge build up being sufficient to ignite the primary fill material.

Abstract: A good discharge lamp which can emit light with wavelengths in the range of 220 nm in an amount sufficient for industrial applications and at the same time can adequately maintain a transmission factor of the radiant light and emits neither water nor hydrogen or the like during luminous operation is achieved by the fact that, in a discharge lamp in which a pair of electrodes are located adjacent to one another encapsulated within a quartz glass fluorescent tube together with mercury and an inert gas, the quartz glass contains an OH radical concentration of a weight of in the range of 300 to 800 ppm. Furthermore, the content of metallic impurities in the quartz glass is limited to a weight less than or equal to 1 ppm.

Abstract: Ignition of an electrodeless lamp, energized by microwave or radio energy, is achieved by disposing an additive material in the lamp envelope along with the primary fill material. In a first embodiment, the additive is at least partially electrically conductive at room temperatures but non-conductive or a vapor at lamp operating temperatures. The preferred additives for this embodiment are mercury sulfide and mercury selenide. In a second embodiment, the additive is a material, such as piezoelectric crystals, that produces sparks in the envelope when the crystals collide with each other, or with other materials, in response to agitation of the envelope. The additive may alternatively build up electrostatic charge by rubbing along the interior surface of the lamp envelope when the envelope is agitated, the charge build up being sufficient to ignite the primary fill material.

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 lamp for providing visible radiation includes tellurium or a tellurium compound in the fill. This substance is present in an amount such that when the fill is excited with sufficient power, substantially all of the radiation resulting from tellurium is emitted at wavelengths exceeding 400 nm. When tellurium is added to a sulfur or selenium based lamp for emitting visible radiation, the spectrum is shifted towards the red region.

Abstract: A glass composition, particularly well suited for use in constructing sodium containing lamp envelopes. The glass composition is comprised of silica doped with yttrium and/or cesium, preferably in combination aluminum.

Abstract: To improve the arc stability of high-pressure discharge lamps, particularly f power ratings of up to about only 250 W, the cathode (4) is formed as an elongated, essentially cylindrical base body (8) having a tapering, conical region (9) terminating in a tip (10). The base body (8), only, is covered with a carbide coating along its length, except for an end portion for electrical connection; the carbide coating starts at the junction or transition between the cylindrical base body portion and the conical end portion. This cathode construction is easier and cheaper to make than prior art cathodes, by coating an essentially cylindrical cathode and then etching or grinding and polishing the tapering end region (9). The electrode is preferably made essentially of tungsten, doped with thorium oxide present up to about 0.6%, optionally also potassium, aluminum and silicon in tiny amounts. The electrode spacing is between 0.4 to 0.

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: A metal halide lamp for producing high-intensity ultraviolet radiation contains an inert gas and a filler. The filler includes iodine and/or bromine in an overall concentration of from about 0.030-1.110 mg/cm.sup.3, mercury in a concentration of from about 0.318-5.250 mg/cm.sup.3, iron in a concentration of from about 0.005-0.036 mg/cm.sup.3, molybdenum in a concentration of from about 0.006-0.120 mg/cm.sup.3, and optionally, cobalt in a concentration of from about 0.0045-0.036 mg/cm.sup.3. The molybdenum is preferably introduced in the form of metal powder. The iodine and/or bromine is preferably introduced in the form of the corresponding mercury halides.

Abstract: An electric discharge lamp has a discharge vessel including pair of opposing planar seals each having a pair of major faces and a pair of minor, side faces. A containment shield surrounds the discharge vessel and includes a glass sleeve and a helically coiled wire secured on the glass sleeve. The glass sleeve is pinched to bevelled ends of the minor, side faces of the seals only and substantially does not engage the major faces of the seal. The wire is fixed around the sleeve in an electrically floating manner, e.g. by clamping fit. With the sleeve secured to the discharge vessel, MH quality photometrics are obtained with a tubular body arc tube without an end coat. The construction of the lamp is simple and effective to protect the outer bulb from being damaged by an explosion of the discharge vessel, and to prevent sodium from disappearing from the discharge vessel as a result of photoemission.

Abstract: An excimer lamp utilizing a high pressure fill. The fill includes a halogen at an operating pressure of greater than about 350 torr or the combination of a halogen and a rare gas at a total operating pressure of greater than about 2.5 atmospheres.

Abstract: The high pressure mercury discharge lamp comprises a quartz glass lamp vessel (1) having a region (2) surrounding a discharge space (3), spaced-apart tungsten electrodes (4) defining a discharge path (5) disposed in the lamp vessel, and connected to current conductors (6) which extend from the lamp vessel to the exterior and a filling of mercury, rare gas and bromine. The lamp has an operating pressure of at least about 200 bar. The discharge space (3) is spheroidal in shape and has specified dimensions. The lamp consumes a power of 70 to 150 W. The lamp has favourable properties which render the lamp suitable for use in optical systems, e.g. for projection purposes.

Abstract: A fluorescent display device capable of realizing mounting of a semiconductor element on a substrate while ensuring an increase in moisture resistance, a decrease in contact resistance at connection between the semiconductor element and a wiring conductor and increased reliability. A semiconductor element is mounted on an extension of a substrate and received in a mounting chamber formed by cooperation of a sealing material, a face plate and the substrate. The semiconductor element is downwardly pressed against the substrate by the face plate, resulting in the semiconductor element being electrically connected to a wiring conductor. The sealing material is made of an inorganic material such as indium-tin alloy or the like which has an operating temperature lower than a sealing medium.

Abstract: A high pressure discharge lamp having a discharge vessel with opposing end chambers includes discharge electrodes each consisting of an open elongate filament of refractory metal wire having a plurality of succesive coil turns extending transverse to the longitudinal axis of the discharge vessel. The filament electrodes are dimensioned so that the discharge arc which terminates thereon is sufficiently retracted into the end chamber of the discharge vessel so that the fill constituents condense on a region of the discharge vessel which is primarily axially between the filament electrodes. In a favorable embodiment, the lamp is a metal halide lamp in which the electrode and the discharge sustaining fill is free of thoria and its compounds.

Abstract: A cadmium/inert gas discharge lamp of the short arc type, which suppresses an unnecessary emission upstream and downstream of the necessary emission spectra in a wavelength range of 210 to 230 nm, achieves a high efficiency of the emission spectra in the range 210 to 230 nm and can be used in very satisfactory manner for industrial applications. Also, a highly efficient projection exposure device through the incorporation of a cadmium/rare gas discharge lamp of the short arc type having good emission spectrum characteristics in the wavelength range 210 to 230 nm, which can transmit in projecting manner fine image patterns with a large depth of focus. The cadmium/rare gas discharge lamp of the short arc type is arranged within a temperature-regulated quartz bulb, and is provided with a pair of adjacently facing electrodes, together with inert gas selected from xenon, krypton, argon, neon or mixtures of them.

Abstract: A metal halide lamp includes a quartz sealed tube having a pair of electrodes using tungsten as the base material. Argon gas, mercury, at least one kind of rare earth metal (e.g., dysprosium, holmium, thulium, neodymium, and erbium), bromine, iodine, and an alkali metal, e.g., cesium, are contained in the sealed tube. The total number of moles of bromine and iodine in the sealed tube is in excess of the number of moles of the rare earth metal. Accordingly, tungsten which is liberated from the electrode during electric discharge can be captured mainly by iodine. A reaction between silicon dioxide, which is a constituent component of the sealed tube, and tungsten is prevented, thereby preventing blackening of the tube wall of the sealed tube.

Abstract: This invention relates to a high pressure sodium vapor discharge lamp the discharge space of which is enclosed by a ceramic vessel having hermetically sealed ceramic end members with electric lead wires connected with electrodes inside the discharge vessel and the discharge vessel contains sodium, noble gas, mercury in a concentration of 0-5 mg/cm.sup.3 and at least one further metal additive having a vapor pressure not exceeding 7.5 torr at 1000K temperature. The discharge lamp according to the invention is further characterized in that the molar fraction of sodium in the total metal additive exceeds 0.5 and the molar fraction of sodium is greater than four times the molar fraction of mercury.

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: An arc tube for a discharge lamp unit which emits light which is suitable in luminous flux, color temperature, and chromaticity. The arc tube is composed of a closed glass ball in which electrodes confront one another and which is sealingly charged with light emitting materials, namely, mercury and a metal iodide of NaI and ScI.sub.3 groups together with Xe inert gas. In accordance with the invention, the closed glass ball has a volume of 20 to 50 .mu.l, the density of the mercury in the closed glass ball is in a range of 2.times.10.sup.-2 to 4.times.10.sup.-2 mg/.mu.l, the density of the metal iodide is in a range of 6.times.10.sup.-3 to 12.times.10.sup.-3 mg/.mu.l, and the charged Xe gas pressure is 3 to 6 atm. These ranges make it possible to readily manufacture on a large scale arc tubes which are substantially equal in performance, being substantially uniform in tube voltage, luminous flux, color temperature and chromaticity.

Abstract: To optimize operating conditions with respect to overall size of a high-psure discharge lamp having a metal halide fill, the wall thickness (d) in millimeters is selected in accordance with a theoretical optimum relationship of d=1.5+0.1.times..cuberoot.P, in which P is the power rating of the lamp, in watts. The optimal theoretical thickness should not vary by more than .DELTA.d=.+-.0.2.times..sup.d, in millimeters, from the theoretical optimal value, with lower power ratings permitting a thinner wall thickness than higher power ratings. Optimizing the wall thickness improves the color rendition index and the light distribution of the emitted light, as well as decreasing the devitrification of the quartz glass of the discharge vessel.

Abstract: To provide a fill in a low-power, high-pressure discharge lamp, which is capable of emitting light within a warm white light (WDL) color or neutral white light (NDL) color, that is, in the ranges of between about 2600 to 4600K, the fill has a relative relationship of sodium halide to scandium halide between 5:1 and 24:1, a relationship of sodium halide to thallium halide of 25:1 to 73:1, and a heat damming or heat retention or reflection coating (15, 16) is located at the end caps of the generally bulbous discharge vessel to provide for a cold spot temperature (Tc) of at least 800.degree. C., and preferably higher.

Abstract: A high intensity electrodeless metal halide arc discharge lamp wherein RF energy is coupled to the arc discharge, contains a halide of praseodymium alone or in combination with other metals such as one or more rare earth metals, Na and Cs and is essentially mercury free (i.e., < 1 mg per cc of arc chamber volume).

Abstract: An alkali metal vapor arc discharge lamp which operates on DC and employs an amalgam of mercury and an alkali metal such as sodium, has a cathode to anode pressure ratio no greater than 5 and a cathode end temperature at least 50.degree. C. hotter than the anode end temperature to prevent cataphoretic separation of the mercury and alkali metal in the arc discharge during operation of the lamp. The lamp is designed to have a cataphoretic driving parameter (CDP) value of less than 150. The CDP is defined as the product of the arc current in amperes, times the arc gap length in centimeters, divided by square of the inner diameter of the arc tube in centimeters.

Abstract: A halide discharge lamp has a an evacuated outer envelope including a getter comprising from about 60 to about 85 percent zirconium, from about 10 to about 20 percent vanadium, and from about 2 to about 10 percent manganese having an activation temperature of less than about 350 degrees Centigrade for reducing the tendency of the lamps to discolor during operation.

Abstract: A high brightness discharge light source includes an arctube having an arc chamber formed therein and in which is disposed a fill of gas energizable to a discharge condition. At least two electrodes extend into the arc chamber and are separated by an arc gap of between 2 and 3.5 mm. The dose of mercury disposed in the arc chamber and various arc tube dimensions are selected so as to achieve a balance between three constraints including operating voltage thereby defining lamp efficacy, convective stability and structural integrity of the discharge lamp. A balance between arc gap, arc chamber diameter, wall thickness and the mercury density of the lamp yield a discharge lamp which achieves a light output on the order of 50,000 lumens per square centimeter.

Abstract: The luminous efficacy and color rendering index of a metal halide lamp containing sodium iodide and scandium iodide is increased, and the color correlated temperature is decreased, by the addition of critical amounts of thallium iodide and lithium iodide.

Abstract: A lamp containing a fill of xenon, mercury and metal halide is disclosed which serves as a light source for lighting applications and is particularly suitable for automotive forward lighting applications. The xenon ingredient operates to provide for instant light necessary for automotive applications, whereas, the mercury and metal halide ingredients operate to provide for a long life, high efficiency lamp relative to either a xenon or tungsten lamp. The dimensions of the xenon-metal halide lamp of the present invention are approximately three-fifths (3/5) of those of a typical tungsten lamp utilized for automotive forward lighting applications. The reduced dimensions of the xenon-metal halide lamp allows for correspondingly reduced dimensions of a related reflector for such a xenon-metal halide lamp which accommodates the needs of aerodynamically styled automobiles.

Abstract: A metal halide lamp apparatus includes a reflecting mirror and a metal halide lamp has a reflecting/thermal insulating film and a frost portion which is partially formed on the lamp outer surface within a predetermined range continued from the reflecting/thermal insulating film. This causes a decrease in an overall illuminance decrease and the attainment of a desired illuminance ratio and prevents the occurrence of irregularity in illuminance and color. In addition, since electrodes are asymmetrically disposed, it is possible to decrease the rate of devitrification of the luminous tube and make an attempt to increase the life of the luminous tube.

Abstract: A metal halide high intensity discharge lamp including a carbon monoxide additive in the arc tube fill to improve lumen maintenance is provided. The metal halide discharge lamp of the present invention comprises: an outer sealed glass envelope; a pair of electrical conductors sealed into and passing through the glass envelope; an arc tube disposed within the outer glass envelope, the arc tube including a pair of spaced electrodes therein with the electrodes being electrically connected to the electrical conductors such that one electrode is electrically connected to one electrical conductor; a chemical fill disposed within the arc tube, the chemical fill comprising mercury, metal halide additives, carbon monoxide, and a starting gas; and a support structure disposed within the outer glass envelope to support the arc tube therein.

Abstract: A high pressure sodium lamp having a fill within an elongated arc tube comprising an inert starting gas, mercury and sodium wherein said mercury and sodium being are in an amount less than two milligrams per cubic centimeter of said volume of the interior of the arc tube wherein the weight ratio of sodium to mercury is less than 1 to 20 whereby the lamp is saturated with sodium and unsaturated with mercury at said predetermined nominal output voltage and does not extinguish at an input voltage exceeding about 90 percent of said rated voltage.

Abstract: Two series connected high pressure sodium arc discharge tubes include a saturated arc tube and an unsaturated arc tube. When the saturated arc tube voltage shifts in value due to changes in operating conditions, the other unsaturated arc tube voltage does not shift to compensate for the voltage increase. Because the unsaturated arc tube voltage does not shift, the rate of voltage shift of the saturated arc tube is smaller in magnitude than otherwise would occur if both arc tubes were saturated.

Abstract: A high-pressure mercury vapor discharge lamp whose envelope two tungsten electrodes disposed therein of tungsten and a filling containing a rare gas, a quantity of mercury larger than 0.2 mg/mm.sup.3 at a mercury a pour pressure of more than 200 bar and at least one of the halogens chlorine, bromine or iodine in a quantity between 10.sup.-6 and 10.sup.-4 .mu.mol/mm.sup.3. The wall load in operation is higher than 1 W/mm.sup.2.

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: A lamp containing a fill of xenon, mercury and metal halide is disclosed which serves as a light source for lighting applications and is particularly suitable for automotive forward lighting applications. The xenon ingredient operates to provide for instant light necessary for automotive applications, whereas, the mercury and metal halide ingredients operate to provide for a long life, high efficiency lamp relative to either a xenon or tungsten lamp. The dimensions of the xenon-metal halide lamp of the present invention are approximately three-fifths (3/5) of those of a typical tungsten lamp utilized for automotive forward lighting applications. The reduced dimensions of the xenon-metal halide lamp allows for correspondingly reduced dimensions of a related reflector for such a xenon-metal halide lamp which accommodates the needs of aerodynamically styled automobiles.

Abstract: A metal halide high intensity discharge lamp including a carbon monoxide additive in the arc tube fill to improve lumen maintenance is provided. The metal halide discharge lamp of the present invention comprises: an outer sealed glass envelope; a pair of electrical conductors sealed into and passing through the glass envelope; an arc tube disposed within the outer glass envelope, the arc tube including a pair of spaced electrodes therein with the electrodes being electrically connected to the electrical conductors such that one electrode is electrically connected to one electrical conductor; a chemical fill disposed within the arc tube, the chemical fill comprising mercury, metal halide additives, carbon monoxide, and a starting gas; and a support structure disposed within the outer glass envelope to support the arc tube therein.

Abstract: Metal halide vapor arc lamps for reprographic and projection processes emitting in the blue, green and red bands with excellent primary color separation and having long life and lumen maintenance contain mercury, zinc, indium, lithium, thallium, a halogen and a rare earth metal such as lanthanum, scandium or dysporsium in the arc tube.

Abstract: A xenon metal halide lamp having an improved electrode structure that is particularly suited for automotive applications is disclosed. The electrode is comprises of a tip portion that is located at one end of a shank with the shank having a filament coiled therearound. The tip and shank portions are designed to allow for high initial current during starting and low current during operation. The coil filament is situated in opposite neck portions of an envelope forming the light source so as to; (1) cause the electrodes to be axially aligned within the light source; (2) keep the shank of the electrode from intimate contact with the envelope thereby preventing the condensation of the mercury and allowing for substantial vaporization of the metal halide ingredients at the neck portion; and (3) prevent the thermal expansion of the electrode from cracking the envelope.

Abstract: A metal halide lamp having a vacuum shroud is disclosed. The vacuum shroud substantially eliminates the detrimental catephoresis effects of operating a metal halide lamp from a low frequency alternating current (A.C.) source or direct current (D.C.) sources, reduces the sodium migration losses typically experienced with a metal halide lamp, reduces the photoelectrons contribution to sodium losses for the metal halide lamp, reduces the detrimental effects of the hydrogen and water that may be within the general confines of such a metal halide lamp, and provides a containment function for an inner envelope that may be operated at a relatively high pressure and possibly experience rupturing to cause the dislodgment of the ruptured material to possibly fracture a glass member confining the metal halide lamp.

Abstract: This invention discloses a high pressure sodium vapor lamp having unsaturated vapor pressure type characteristics with sodium and mercury contained in an arc tube. The sodium is enclosed in an amount sufficient to exhibit unsaturated vapor pressure type characteristics while the mercury is enclosed in an amount M.sub.Hg calculated by the following formula: ##EQU1## where M.sub.Hg : the amount of mercury enclosed (mg)D: the internal diameter of the arc tube (cm)L: the electrode-to-electrode distance (cm)V.sub.olume : the volume of the arc tube (cc)V.sub.n : the rated lamp voltage (Volt).

Abstract: A semiconductor wafer one side of which has been coated with an ultraviolet sensitive material is exposed to light radiated from a rare gas-mercury discharge lamp. A rare gas-mercury discharge lamp filled with a rare gas such as xenon and mercury as principal luminous components thereof and capable of radiating light having the maximum peak wavelength at 365 nm is used as the lamp, and the coated side of the wafer is exposed, through a lens system having a high transmittance for light having a wavelength of 365 nm and a photomask, to the light radiated from the lamp so as to print a reduced image of the mask pattern on the coated side of the wafer. Use of the above-described rare gas-mercury discharge lamp allows to print a highly-integrated pattern having a narrow linewidth efficiently and in shorter exposure time owing to its high radiation intensity at 365 nm.

Abstract: A semiconductor wafer can be exposed by arranging a combination of electrodes in an opposed relation with an interelectrode distance of not more than 15 mm in a closed discharge cavity, enclosing, within the cavity, mercury as a light-emitting discharge component in an amount such that the vapor pressure of mercury reaches 0.4-5 atms during discharge lighting, forming a discharge between the combination of electrodes while controlling the discharge current at not less than 10 A, and irradiating light, which has been radiated as a result of the discharge and contains at least one of light components having wave-lengths of 405 nm and 436 nm respectively, onto the surface of a photoresist applied on the semiconductor wafer through a photomask or reticle and a lens which permits transmission of the light having wavelength of 405 nm or 436 nm therethrough.

Abstract: A fill composition for a high intensity discharge device including mercury, niobium oxytrihalide, and a molecular stabilization agent is provided. The molar ratio of niobium oxytrihalide to the molecular stabilization agent in the fill is in the range of from about 5:1 to about 7.5:1. Niobium oxytrihalide is present in the fill in sufficient amount to produce, by dissociation in the discharge, atomic niobium, niobium oxide, NbO, and niobium dioxide, NbO.sub.2, with the molar ratio of niobium-containing vapor species to mercury in the fill being in the range of from about 0.01:1 to about 0.50:1; and mercury pressure of about 1 to about 50 atmospheres at lamp operating temperature. There is also provided a high intensity discharge device comprising a sealed light-transmissive arc tube; the arc tube including the above-described fill; and an energizing means for producing an electric discharge within the arc tube.

Abstract: A high-pressure sodium vapor lamp, comprising a hermetically closed tube made of a translucent material of high thermal resistivity as alumina, at least two electrodes arranged in the tube, is filled with noble gas particularly xenon and with vapors of sodium and mercury and/or cadmium under pressure of saturated vapors at the temperature of operating. The quantity of the vapors of mercury and/or cadmium is in the range from 0.5 to 5.0 micromol for each centimeter of length of the discharge arc initiated between the electrodes. The high-pressure sodium lamp with the mentioned quantity of additives is assured a long lifetime of operation.

Abstract: Disclosed is a short-arc high intensity discharge lamp having an improved arc tube as its light source. The arc tube contains an inert gas and a dosage comprising Indium (In), Mercury (Hg), Dysprosium (Dy), and Iodine (I).

Abstract: A high-pressure sodium lamp is connected to a d.c. power supply through a ballast, to operate it with a current containing a d.c. component. The relation between the ratio l/d of the inter-electrode distance l (mm) to the inner diameter d (mm) of the arc tube of the high-pressure sodium lamp and the sodium vapor pressure P.sub.Na (kPa) in the arc tube is maintained at P.sub.Na .gtoreq.6.0 (l/d-5.8), thus making it possible to operate the high-pressure sodium lamp with a current containing a d.c. component without causing a significant color separation which otherwise might be the result of cataphoresis.

Abstract: A gas discharge lamp according to the invention has an at least approximately rectilinear and contracted arc and a high efficiency even in a horizontal operating position. Consequently, the lamp is suitable for use, when arranged in a reflector, as a vehicle headlight lamp. The lamp comprises an ionizable filling of rare gas, mercury, and metal iodide, the quantity of mercury being dependent upon the inner diameter D of the lamp envelope (1), the distance d between the tips of the electrodes (2), and the distance l over which the electrodes project into the lamp envelope. The values of D, d, l and the wall thickness t of the lamp envelope lie within indicated limits. The lamp, which may be provided with a screen, may have a lamp cap or may be incorporated into a reflector with a front pane.

Abstract: A high pressure sodium lamp having an inner arc tube operated at an increased wall temperature so as to improve the efficacy of the lamp is disclosed. The improved high pressure sodium lamp has an arc tube which reduces the sodium losses typically experienced by high temperature operation. Also disclosed are desired parameters of the arc tube.