Abstract: Metal halide lamps have a discharge vessel operable at a high coldest spot temperature. The discharge vessel encloses a discharge space comprising an ionizable gas filling and, in addition to Hg, also an alkali iodide of Na of Li or a combination of both. According to the invention, the filling also comprises TbI3 or GdI3 or a combination thereof.

Abstract: Arc tube (10) has a bulbous body (12) with a hollow center portion (14) and opposite ends (16, 18). Each of these ends has a cylindrical terminal-receiving section (20, 22) extending therefrom. The hollow center portion (14) has an internal length A and an internal diameter B that provides an aspect ratio of less than 5 and an outer surface area to inner surface area ratio, measured in square units, of less than 1.5. Electrodes (24) and (26) are hermetically sealed in the terminal-receiving sections (20, 22). The lamp uses less than 7 mgs of mercury. The low pressure operation allows the use of the arc tube in lamps without a shroud and the low mercury allow the lamp to pass TCLP requirement and be conventionally landfilled.

Abstract: A metal halide lamp for an automobile headlight is provided, which includes an arc tube in which a pair of tungsten electrodes are provided at both ends and a metal halide as a main component of a luminescent material and xenon gas as a buffer gas are sealed, wherein the tungsten electrodes contain not more than 0.4 wt % of thorium oxide, the metal halide contains scandium iodide, and a pressure of the xenon sealed in the arc tube is at least 0.4 MPa. This makes it possible to provide a long-life metal halide lamp for an automobile headlight that can achieve a further improved lumen maintenance factor and other life characteristics during 2000 hours or more of lighting.

Abstract: A high-pressure mercury lamp is provided that includes a transparent envelope made of quartz glass, in which mercury, halogen, and a rare gas are sealed and a pair of electrodes provided in the transparent envelope. The amount of the halogen sealed in the transparent envelope is in the range from 1.0×10−6 &mgr;mol/mm3 to 1.0×10−2 &mgr;mol/mm3, and 2.5 mol % to 25 mol % of oxygen with respect to the amount of the halogen is present in the transparent envelope. The high-pressure mercury lamp can prevent blackening of an inner wall of the transparent envelope from occurring over a long period of lighting without deteriorating the startability or lamp characteristics, thus achieving a long life.

Abstract: A [thallium free] high pressure ceramic metal halide lamp having superior dimming characteristics with a fill composition including MgI2 and/or MgBr2.

Abstract: A light source with a sealed, light-transmissive tube filled with high pressure gases or high pressure gas mixtures and a microhollow cathode (MHC) discharge capable of excimer production are provided.

Abstract: A metal halide discharge lamp can include a light emitting tube having a discharge chamber formed in the light emitting tube and containing no mercury. A pair of electrodes can be provided with a portion, which projects into the discharge chamber. The discharge chamber can include a buffer gas, which also acts as a starter gas, of xenon (Xe) in an amount of 7-20 atmospheres at room temperature, and at least one kind of metal halide. The light emitting tube can have a positive resistance range in current-voltage characteristics relative to a varying input electric power. In the positive resistance range, the light emitting tube can be driven by an electric power which is less than or equal to a rated power supplied during steady lighting. In the metal halide lamp of the invention, even if the input electric power to the light emitting tube is varied, sudden unintentional extinguishment does not occur, and varying range of light color can be narrowed.

Abstract: A solid halogen-containing lamp fill material and a method of introducing small amounts of halogen into a HID lamp are disclosed. The solid material may include an admixture of a metal and a metal halide in the form of spheres of high purity, uniform size and uniform composition. Solid lamp fill material and methods of introducing small quantities of one or more metals into a HID lamp are also disclosed.

Abstract: Disclosed is a metal halide discharge lamp which essentially permits disusing mercury. The metal halide discharge lamp comprises a refractory and transparent hermetic vessel, a pair of electrodes fixed to the hermetic vessel, and a discharge medium sealed in the hermetic vessel and containing a first halide, a second halide and a rare gas, the first halide being a halide of a metal which achieves a desired light emission, the second halide having a relatively high vapor pressure, being at least one halide of a metal which is unlikely to emit a visible light compared with the metal of the first halide, and acting as a buffer gas.

Abstract: Disclosed is a cold cathode type fluorescent lamp operated with a low voltage while it has a greatly increased life. The cold cathode type fluorescent lamp has a fluorescent tube including a fluorescent material formed thereon. A discharge gas includes vapors of mercury and an inert gas by a ratio of approximately 1:0.6 to 1:2.0. A first base and a second base are installed at both end portions of the fluorescent tube. A first electrode is disposed in the fluorescent tube, and a second electrode is disposed in the fluorescent tube. A first electron-emitting member is fixed on the first electrode, and a second electron-emitting member is fixed on the second electrode. The cold cathode type fluorescent lamp can instantaneously operate without preheating the electrodes, and cold cathode type fluorescent lamp can have greatly increased life because the cold cathode type fluorescent lamp can continuously operate when the electron-emitting members are broken.

Abstract: Metal halide lamps are disclosed having a discharge vessel with a ceramic wall. The discharge vessel encloses a discharge space comprising an ionizable gas filling and, in addition to Hg, an alkali iodide of Na or Li or a combination of both. The filling also includes TbI3 or GdI3 or a combination thereof.

Abstract: Low-pressure mercury discharge lamp (1) comprising an at least partly substantially cylindrical discharge vessel (3) having a diameter D, wherein two electrodes are present near respective ends of said discharge vessel (3), which discharge vessel (3) is filled with a mixture of inert gasses having a pressure P and which discharge vessel (3) contains an amount of mercury, wherein D×P is at least 5.2 mPa. The invention is based on the novel understanding that a higher filling pressure of the inert gas mixture causes a lower mercury consumption in the lamp (1).

Abstract: To provide a high-efficiency and long-life high intensity discharge lamp that is obtained by a configuration in which a neon gas or a neon-based gaseous mixture is filled as a starting-assistance rare gas for an alumina ceramic arc tube, and a filling pressure is set to 13 kPa or more. The high intensity discharge lamp is provided with the alumina ceramic arc tube having a discharge arc tube, alumina ceramic narrow tubes formed at both end portions of the discharge arc tube, electrodes and power feeders, the electrodes and the power feeders being arranged to form spaces in the narrow tubes. The discharge arc tube is filled with the neon gas or the neon-based gaseous mixture as the starting-assistance rare gas at a filling pressure of 13 kPa or more. This prevents a discharge arc from jumping from tip portions of the electrodes to the spaces at starting of the lamp, and avoids occurrence of cracks and breakages in the narrow tubes.

Abstract: A short arc mercury discharge lamp including an arc tube filled with at least mercury and a rare gas, a cathode and an anode positioned opposite to each other within the arc tube, the cathode having an tapered area which tapers in a direction towards the anode and a projection which protrudes from the tapered area in a direction towards the anode. The amount of mercury to be added in the arc tube is in a range of 0.2≦n≦52, where n is the weight (mg/cm3) of the mercury per unit of volume, and a pressure of the rare gas to be added in the arc tube is in a range of 0.1≦p≦800, where p is the pressure (kPa) of the rare gas at an ambient temperature of 25° C.

Abstract: Disclosed is a metal halide discharge lamp which essentially permits disusing mercury. The metal halide discharge lamp comprises a refractory and transparent hermetic vessel, a pair of electrodes fixed to the hermetic vessel, and a discharge medium sealed in the hermetic vessel and containing a first halide, a second halide and a rare gas, the first halide being a halide of a metal which achieves a desired light emission, the second halide having a relatively high vapor pressure, being at least one halide of a metal which is unlikely to emit a visible light compared with the metal of the first halide, and acting as a buffer gas.

Abstract: A discharge lamp for an automobile headlight has a light color that lies in a region common to the following three regions: a region bounded by an ellipse with a color point (u, v)=(0.224, 0.331) as a center thereof, a major axis of 0.080, a minor axis of 0.024, and an angle from a u axis of 35 degrees in the CIE 1960 UCS diagram; a region bounded by an ellipse with a color point (u, v)=(0.220, 0.332) as a center thereof, a major axis of 0.060, a minor axis of 0.022, and an angle from a u axis of 15 degrees in the CIE 1960 UCS diagram; and a region bounded by an ellipse with a color point (u, v)=(0.235, 0.335) as a center thereof, a major axis of 0.060, a minor axis of 0.030, and an angle from a u axis of 30 degrees in the CIE 1960 UCS diagram.

Abstract: A ballast and metal halide lamp circuit improvement designed to reduce lamp lumen depreciation over the life of the lamp, wherein the circuit comprises a high frequency electronic ballast configured to generate high voltage starting pulses, and a metal halide lamp further comprising an arc tube containing an ionizable medium, and having main electrodes sealed into opposed ends of the arc tube, the ionizable medium including mercury, a metal halide, and an inert gas selected from the group consisting of argon, krypton, and xenon and mixtures thereof, wherein the starting pulses are suitable for starting high fill pressure metal halide lamps, and said inert gas is at a cold pressure of greater than 50 torr.

Abstract: A high-pressure metal halide discharge lamp having a power rating of at most 100 W is provided with a discharge vessel having a translucent ceramic wall with a thickness d of at least 1.2 mm. In the discharge space enclosed thereby, two electrodes are arranged with their electrode tips at a mutual interspacing EA. The discharge vessel contains an ionizable filling comprising at least Na and a halide.

Abstract: A display screen comprising a phosphor composition which includes a phosphor and a phosphor coating with a group of metal-oxygen compounds, the group of metal-oxygen compounds containing an yttrium-oxygen compound, is characterized by a surprising improvement in picture brightness, color purity and adhesion of the phosphor composition to the glass of the display screen. The phosphor layer exhibits a high packing density of the phosphor material. The phosphor layer further exhibits a good homogeneity and is free from “pinholes”. In addition, the structured phosphor layer shows a high definition.

Abstract: A high pressure mercury lamp in which formation and spreading of milky opacification in the fused silica glass forming the discharge vessel can be advantageously prevented, and thus a rapid decrease of screen illuminance prevented, when it is used as the light source of a liquid crystal projector and the like by, in a high pressure mercury lamp in which a discharge vessel of fused silica glass contains a pair of opposed tungsten electrodes, mercury in an amount that is at least equal to 0.16 mg/mm3, rare gas, and at least one halogen, and in which the wall load is at least equal to 0.8 W/mm2, the amount of mercury added being fixed in a range from 2×10−4 to 7×10−3 &mgr;mole/mm3, and/or the at least one halogen being in the form of a carbonless halogen compound, and/or the average OH radical concentration in an area of a wall of the discharge vessel at a depth of 0.2 mm from an inner surface of the wall of the discharge vessel being at most 20 ppm.

Abstract: A high-pressure mercury vapor discharge lamp comprises an arc tube in which a pair of electrodes are provided and in which a rare gas as a starting gas, a material from which a free halogen is to be produced during a lighting operation, and mercury are enclosed. The arc tube satisfies X/L≧88, in which X(W) is a lighting operation power and L (mm) is a distance between the electrodes. The high-pressure mercury vapor discharge lamp satisfies the following expression: 1.2≦&phgr;/(X×10−2+3.2)≦1.6 in which &phgr; (mm) is the inner diameter of the arc tube. Therefore, the high-pressure mercury vapor discharge lamp has a high luminance, a good emission spectrum, and a long life.

Abstract: A reflector lamp 10 has a vitreous outer envelope 12 formed of a concave reflector 14 and a light-transmitting 16 cover peripherally sealed thereto. The concave reflector and cover are symmetrically arrayed about a longitudinal axis 18 and a substantially cylindrical, hollow neck 20 having a given depth is affixed to the concave reflector opposite the cover. The neck 20 also is symmetrically arrayed about the longitudinal axis 18 and has a substantially closed bottom 21. At least two eyelets, 22, 24, respectively, are sealed in the bottom 21 and a light source capsule 26 is positioned in the concave reflector and aligned with the longitudinal axis 18. The light source capsule 26 has a first end 28 situated in the neck 20 and a second end 30 extending into the concave reflector. The light source capsule 26 comprises a quartz arc tube 32 containing an arc generating and sustaining medium and a surrounding aluminosilicate glass shroud 34.

Abstract: A metal halide lamp comprises a pair of electrodes and a discharge vessel filled with at least one metal halide comprising at least one rare earth metal halide, halogen in excess of the stoichiometry of the metal halide(s), mercury, and a rare gas. The amount of the mercury is between 7.7 mg/cc and 9.9 mg/cc, the excess halogen is 25-100% (in terms of atoms) of the halogen included in the metal halide(s), and the rated tube power for 200V rated tube voltage is 2000 W-3000 W.

Abstract: A metal halide lamp in which the radiant efficiency is not adversely affected, in which outstanding color reproducibility is obtained, and which is suitable for a light source of an OHP or a direct projector is achieved, according to the invention, by the fact that, within an arc tube provided with a pair of electrodes, together with mercury and a starting rare gas, halides of dysprosium (Dy), yttrium (Y) and cesium (Cs) are encapsulated with the molar ratio of the encapsulated metals Dy to Y is being fixed in the range of 0.3.ltoreq.Dy/Y.ltoreq.1.0. In this way the green portion to which there is a sensitive visual reaction is reduced, the blue portion increased, and thus the color reproducibility is increased.

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: The apparatus has a light transmitting bulb for confining a discharge therein, a fill sealed within the light transmitting bulb and including a rare gas and a metal halide emitting a continuous spectrum by molecular radiation, and a discharge excitation source for applying electrical energy to the fill and for starting and sustaining an arc discharge, and the metal halide includes one kind of halide selected from the group consisting of an indium halide, a gallium halide, and a thallium halide, or a mixture thereof, and in that the light transmitting bulb has no electrodes exposed in discharge space and further this construction utilizes the continuous spectrum of molecular radiation of the metal halide and thereby achieves high color rendering properties and high luminous efficacy simultaneously without using mercury as the fill.

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 sodium containing lamp constructed to include of a fused quartz or fused silica arc chamber wherein the fused quartz and/or fused silica contains less than about 0.05 parts per million sodium. The arc chamber of the invention demonstrates a resistance to sodium diffusion resulting in a longer lived lamp with excellent color maintenance.

Abstract: A highly efficient discharge lamp has a color rendering index of about 85, a lumens per watt rating of about than 90, a correlated color temperature of 3000.degree. K., and a wall loading of about 21 W/cm.sup.2. The lamp has an outer glass envelope and a pair of electrical conductors extending into the interior of the glass envelope; a quartz discharge tube disposed within the outer envelope and including a pair of spaced electrodes which are electrically connected to the electrical conductors for creating an electrical discharge during operation of the lamp, the discharge tube having an arc chamber. An arc generating and sustaining medium is provided within the arc chamber and includes the halides of sodium, scandium, lithium, dysprosium and thallium, a fill gas selected from argon and xenon, and a given quantity of mercury to achieve a desired lamp voltage. In a preferred embodiment of the invention the halides are iodides and are present in the mole ratio of about 24-44:1:9.

Abstract: A metal-halide discharge lamp for photooptical purposes has a small electe spacing of less than 15 mm, preferably 2-8 mm, to provide an essentially pin-point light source, and a fill which contains AlI.sub.3 in an amount between 0.1 and 4.5 mg/cm.sup.3. Other filling components may in particular be halides of mercury, indium, thallium or cesium; up to 2 mg/cm.sup.3 of AlBr may be added. The lamp is particularly adapted for combination with a, preferably parabolic, reflector.

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: A metal halide lamp in which rare earth halides are encapsulated and the occurrence of milky cloudiness is suppressed to achieve a prolongation of the service life of the lamp. To achieve this result, inert gas, mercury, indium halide, cesium halide, and rare earth halides are encapsulated in an emission part, with the encapsulation amount of the indium halide being from 0.8 micromole to 8.0 micromole/cm.sup.3 of tube volume, and the lamp is operated with an essentially horizontal arc axis using a direct current. Furthermore, iodine and bromine are contained in the halogen which forms the halides, and there is a ratio of the iodine atom number to the total halogen atom number is greater than or equal to 50%.

Abstract: In a metal halide lamp container 1 sealed with mercury and rare gas, GdX.sub.3, LuX.sub.3, and CsX where halogen is iodine, bromine, or their mixture are sealed in a total weight of 1 mg/cc or more, with the weight of CsX defined within a range of 15% or more to 50% or less of the total halides, and the weight ratio of GdX.sub.3 and LuX.sub.3 is set in a range of 0.1.ltoreq.GdX.sub.3 /LuX.sub.3 .ltoreq.10. In addition to GdX.sub.3, LuX.sub.3, and CsX, at least one of thallium halide and dysprosium halide is added. Or DyX.sub.3, LuX.sub.3, NdX.sub.3, and CsX where halogen is iodine, bromine or their mixture are sealed in the specified total weight, with the weight ratio of CsX defined in the above range.

Abstract: The high pressure metal halide lamp has in a light transmitting discharge vessel discharge electrodes and a filling made of a rare gas, a buffer gas and at least one halide chosen from hafnium and zirconium bromide and chloride. The filling also includes a metal chosen from tin, tantalum and antimony in elementary form and is free from iodine in an amount exceeding 0.5 .mu.mol/cm.sup.3 discharge space. The lamp has considerably improved light generating properties.

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: 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: 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 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: In a metallic vapor discharge lamp, in whose arc tube provided with electrodes are encapsulated together with mercury and inert gas, whose quantity is adequate for maintaining arc discharges, an adequate quantity of iron and an adequate quantity of a metal, in which at least one of the metals tin, magnesium, bismuth, thallium, cadmium or manganese is selected, together with halogen, as a result of the fact that the encapsulated halogen at least contains bromine, whose weight ratio to the total halogen is 0.26%, the adhesion of iron to the inside of the arc tube is prevented and consequently a radiation intensity of the ultraviolet rays effective for curing paints or inks is maintained over a long period of time.

Abstract: The high-pressure discharge lamp has a filling in a discharge vessel (1) which includes a rare gas and a metal compound (2) chosen from hafnium halides and zirconium halides. The halide evaporates and discomposes to form incandescent, condensed metal particles. The lamp may be electrodeless and may in addition contain a buffer gas as a component of its filling. Alternatively, the lamp may have internal electrodes (13) and contain mercury (12) as a buffer gas. The lamp has favorable light generating properties, in particular a good color rendering, and in addition may have a very high luminous efficacy.

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: 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: The high-pressure lamp has a fill including a metal halide of two groups, which the first group is a first rare earth halide of dysprosium, thulium and optionally holmium, and a second group of rare earth halide, namely cerium, neodymium, praseodymium, lanthanum; and an alkali metal halide, such as sodium halide and/or cesium halide, preferably iodide or bromide of sodium and/or cesium. The lamp has a high proportion of light radiation in the red range of the color spectrum to provide substantially improved color rendering indices, particularly in the Ra.sub.8 region, thereby providing better color balance, without loss of lifetime.

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 scandium halide and alkali metal halide discharge lamp has a chemical fill in the arc tube comprising an inert starting gas, mercury, alkali metal iodides, scandium iodide and platinum metal as an additive for reducing the tendency of the lamps to discolor during operation.

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 of the present invention comprises a luminous tube alone without any outer bulb, the luminous tube containing metal halides such as neodymium halides (NdX.sub.3), dysprosium halides (DyX.sub.3) and cesium halides (CsX) in a total amount by mole of 1.times.10.sup.-6 to 8.times.10.sup.-6 mol/cc and the following molar ratios: ##EQU1## as well as rare gas serving as starting auxiliary gas and mercury serving as buffer gas. This structure permits a predetermined vapor pressure of the metal halides sealed in the luminous tube to be obtained without increasing the wall load, as well as the formation of a metal halide lamp having a long life and good color characteristics.