Abstract: A quartz arc tube for a metal halide lamps and its method of making are described. The quartz arc tube has a cylindrical design which promotes a nearly symmetric longitudinal surface temperature profile during operation. The profile has a maximum temperature of about 900° C. which allows for longer operating life at high average wall loadings.

Abstract: To improve the ratio between first and second halides sealed in a mercury-free lamp, thereby providing a metal halide lamp which has a high luminous efficiency and a low lamp voltage reduction and emits light of an appropriate color and an automotive headlamp apparatus incorporating the same.

Abstract: An ultra-high pressure mercury lamp in which both devitrification and also breakage of the discharge vessel can be eliminated. In the ultra-high pressure mercury lamp, there is a pair of opposed electrodes in a fused silica glass discharge vessel filled at least 0.15 mg/mm3 mercury, and an alkali metal concentration in the area from the inside surface of this discharge vessel to a depth of 4 microns that is at most 10 wt.ppm.

Abstract: A mercury-free metal halide lamp includes an arc tube including a pair of electrodes inside the tube. In the arc tube, a rare gas and a metal halide are contained, and no mercury is contained. The mercury-free metal halide lamp is horizontally operated such that the pair of electrodes is substantially horizontal. The mercury-free metal halide lamp further includes magnetic field applying means for applying a magnetic field including a component substantially perpendicular to a straight line connecting heads of the pair of electrodes in a substantially vertical direction. The density of halogen atoms evaporated during steady-state operation with respect to unit inner volume of the arc tube is 20 &mgr;mol/cc or more.

Abstract: An arc discharge vessel having electrodes disposed therein, a fill within the discharge vessel wherein the arc discharge vessel is comprised of alumina including the following dopants in parts per million: 50≦MgO≦1500; 100≦HFO2 ≦1500; 0≦ZrO2≦700; 0≦Y2O3≦300; 0≦Sc2O3≦1000; 0≦Dy2O3≦1000; 0≦Tb2O3≦1000; with the proviso that at least 5 ppm Y2O3, Sc2O3, Dy2O3, Tb2O3, or mixtures thereof is included.

Abstract: A metal halide discharge lamp which is capable of reducing a color change when subjected to a variation in the lamp power and/or the voltage supplied to the lamp. The metal halide lamp has an arc tube filled with at least sodium halide and scandium halide. The arc tube is formed at its opposite ends with electrodes which gives an arc discharge therebetween. The lamp has regulator means for keeping a coldest spot temperature of the arc tube at 550° C. or more when operating the lamp at a lamp power which is 50% or rated lamp power. It is found that when the lamp is configured to have a coldest spot temperature at 550° C. or more when operating the lamp at a lamp power which is 50% of the rated lamp power, the lamp shows much less color variation even subjected to the lamp voltage variation, thereby maintaining a desired color.

Abstract: An electrodeless lamp is disclosed. The electrodeless lamp according to the present invention is characterized in that SnI2 is used as a major component filled into a bulb as a filler, and the filler is excited by applying a microwave or high frequency to the bulb for thereby generating a visual ray for thereby obtaining a certain color temperature proper as a light source and implementing a faster light emission start-up at a lower cost without an additive.

Abstract: A low-pressure gas discharge lamp having a gas discharge vessel containing a gas filling including a copper compound. The copper compound is selected from the oxides, chalcogenides, hydroxides, hydrides and the metalorganic compounds of copper. In addition to the copper compound, the gas filling includes a buffer gas such as argon, and may also include a thallium compound and/or a copper halogenide.

Abstract: A metal halide lamp with red emission equivalent to or exceeding that of a blackbody source of equal correlated color temperature. A metal halide chemistry containing CaI2 plus a complexing metal halide of AlI3 or GaI3 is used to substantially increase red emission of a metal halide lamp. The inclusion of TlI in the fill chemistry is also important in influencing Ca to preferentially emit atomic and molecular red radiation of the visible spectrum while suppressing blue radiation. Optionally, a shroud of neodymium doped glass is also used to significantly filter transmission of yellow light, thereby further improving the proportion of red emission while maintaining a sufficiently white color and good general color rendering.

Abstract: An apparatus and method for obtaining short-term color stability in an HID lamp, the apparatus comprising in a first embodiment a high intensity discharge lamp with a discharge vessel and electrodes; with a filling within the discharge vessel containing a metal halide dose of at least 20 mg/cc, where volume is defined as the volume of the main cylindrical section of the discharge vessel. In a preferred embodiment, the filling within the discharge vessel contains Hg of at least 20 mg/cc, where volume is defined as the volume of the main cylindrical section of the discharge vessel. In a yet further aspect, the resulting color temperature is stabilized independent of the shape and frequency of the current and voltage waveforms that drive the HID lamp.

Abstract: A metal halide lamp has a ceramic discharge vessel with an inside length L, an inside diameter D, and an aspect ratio L/D of between 3 and 5. The fill gas includes xenon, mercury, sodium halide, and halides of rare earth metals. Hydrogen iodide voltage spikes during start-up are related to product of volume and the cold xenon pressure, which are adjusted to limit the spikes. Voltage crest factor is related to the product of total operating pressure and the square of the inside diameter, which are adjusted to limit the crest factor. The ceramic discharge metal halide (CDM)lamp may have a power rating of 200 W or more and can be used with an existing ballast for a high pressure sodium (HPS) lamp of like power rating.

Abstract: Low-pressure mercury vapor discharge lamp provided with a discharge vessel (10). The discharge vessel (10) encloses a discharge space (11), provided with a filling of mercury and a rare gas, in a gastight manner. At least a part of an inner surface of the discharge vessel (10) is provided with a transparent layer (16) comprising an oxide of scandium, yttrium, or a rare earth metal (lanthanum, cerium, gadolinium, ytterbium, and/or lutetium). The discharge lamp is characterized in that the transparent layer (16) comprises a borate or a phosphate of an alkaline earth metal and/or of scandium, yttrium or a further rare earth metal. Preferably, the alkaline earth metal is calcium, strontium and/or barium. The further rare earth metal is preferably lanthanum, cerium and/or gadolinium. The oxide is preferably Y2O3 or Gd2O3. Preferably, the transparent layer (16) has a thickness of between 5 nm and 200 nm. A luminescent layer (17) is preferably provided on top of the transparent layer in the discharge vessel.

Abstract: A method and apparatus for increasing the emission amount of red such that it is made the same as the emission amount of green and blue, to enable the application state of the fluophors to be easily tested within a short time. Light from a discharge lamp of the short-arc type in which the arc tube is filled with cadmium and rare gas and which has emission lines between 200 nm and 230 nm is radiated onto fluophors of a test article such as the substrate for a display or the like. The fluorescence produced by these fluophors is received by a CCD sensor, and displayed in a display part, and thus the application state, such as faults of the fluophors or the like, is checked. The images picked up by the CCD camera can also be input to a control device and thus testing can be automated.

Abstract: A high-pressure discharge lamp is configured to regulate the relationship between the radius r (mm) of the tungsten rods forming the electrodes and the lamp current I (amperes) using the formula 1.5 ≤ I π · r 2 ≤ 9 when the ratio of the circumference of the circle to its diameter is expressed as &pgr;. The high-pressure discharge lamp suppresses early blackening, and achieves a long-life light source.

Abstract: A discharge lamp comprises an arc tube 6 made of a translucent ceramic dosed with a metallic halide. The discharge is conducted between electrodes 20 disposed in the arc tube 6. The arc tube 6 comprises a main tube body 11 having a large diameter portion 11A and a small diameter portion 11C, and a narrow tube 12 airtightly fixed to the small diameter portion 11C while penetrating the small diameter portion 11C. In the discharge lamp, supposing that L (mm) is the length of a protrusion from the main tube body of the narrow tube portion 12 and P (W) is the rated power of the discharge lamp, L and P satisfy the relationship (P+268.75)/31.25≦L≦(P+456.25)/31.25 and 200≦P≦450.

Abstract: A metal halide discharge lamp which essentially permits disusing mercury is provided. 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 is a halide of a metal which achieves a desired light emission. The second halide has 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 acts as a buffer gas.

Abstract: An electrodeless discharge lamp operating apparatus includes a transparent discharge vessel (1) in which a luminescent substance is enclosed; a coil (3) for generating an alternating electromagnetic field that discharges the luminescent substance; a power source (4) for supplying alternating current to the coil (3). The coil (3) comprises at least a magnetic material, and is disposed on an inner side than the outer side wall of the discharge vessel (1), and the luminescent substance comprises at least a rare gas, and does not comprise mercury.

Abstract: A high-pressure discharge lamp includes: a quartz glass bulb; conductive elements; and a pair of electrodes. The conductive elements are airtightly sealed at sealing portions of the quartz glass bulb. Each electrode of the pair of electrodes is disposed so as to be opposite each other and connected to one of the conductive elements. The quartz glass bulb is formed as a single piece unit by using a synthetic quartz whose viscosity is about 1013 poise or more at about 1200° C.

Abstract: A mercury-free high pressure sodium vapor lamp is dosed with sodium, xenon and zinc as an elemental metal additive. The addition of the metal additive prevents an undesirable low-voltage operating mode of the sodium-xenon discharge associated with a mercury-free HPS lamp, which otherwise occurs when sodium is no longer available to participate in the arc discharge.

Abstract: A mercury-free metal halide lamp with a light efficiency of at least 70 Im/W and a color rendering index of at least 80 has a ceramic discharge vessel, into which electrodes are introduced in a vacuum-tight manner. The fill comprises the following components: an inert gas which acts as buffer gas, a compound of a halogen X with at least one of the metals hafnium and/or zirconium (referred to below as metal halide HZM), this halide being referred to below as HZH for short, HZH simultaneously performing tasks of voltage gradient formation and of promoting the cycle, a light generator comprising at least a further metal halide, at least one further metal halide MYn which vaporizes readily and is used as voltage gradient generator, the specific molar content of HZH being greater than or equal to 3 &mgr;mol/cm3. In addition, the following relationship applies: 5≦(X+Y)/HZM≦15, resulting in a lamp service life of more than 5000 hours.

Abstract: A high pressure mercury lamp comprises a quartz envelope that contains an atmosphere and a pair of arc-discharge electrodes. These are coil-wound tungsten that has been doped to grain-stabilize the tungsten crystalline structure, e.g., with potassium or potassium and alumina. Preferred potassium doping levels of the tungsten material are in the range of 35-75 ppm. A suitable commercial product of alumina and potassium doped tungsten material is Type BSD-Sylvania. The atmosphere generally comprises a rare gas like xenon, to which is added no more than 0.2 mg/mm3 of mercury so as to keep operating pressure under 200 bar (197 atm). But the electrical power applied is sufficient to maintain arc power loadings of at least 150 watts/mm. The resultant wall loading is more than 0.8 watts/mm2, and lamp operating-power levels can be greater than 150 watts.

Abstract: An electrodeless lamp includes a stationary bulb (10) containing a fill for producing a discharge, the fill has a primary radiating material which ordinarily produces an unstable discharge in the absence of bulb rotation. The fill further includes an alkali metal in an amount sufficient to stabilize the discharge without bulb rotation. The alkali metal may be, for example, cesium bromide. Preferably, the fill is excited by a non-stationary electric field (E, E1) such as, for example, a circular polarized electric field.

Abstract: Mercury-free metal halide lamp with a warm white luminous color, the fill of which comprises the following components: an inert gas which acts as a buffer gas; a first group of metal halides (MH), the boiling point of which is above 1000° C. (preferably above 1150° C.), the first group comprising at least Dy and Ca used simultaneously as metals, and the molar ratio of the two metal halides Ca-MH:Dy-MH being between 0.1 and 10; these are components with a low volatility which are present in saturated form; a second group of metal halides, the boiling point of which is below 1000° C. (preferably below 900° C.

Abstract: A discharge lamp for providing visible radiation includes a lamp envelope which is made of light transmissive material a fill in the envelope including either calcium halide or strontium halide together with either elemental sulfur or elemental selenium in gaseous form which is obtainable when the fill is excited by sufficient power in operation, in an amount such that the excited fill emits a discharge of visible radiation from the fill with substantially all of the radiation being molecular radiation which is emitted in the visible region of the spectrum. The calcium halide or strontium halide operates at a vapor pressure which provides a significant amount of radiation in the red region of the spectrum therefrom and the overall spectrum has a color rendering index of about 87 or more.

Abstract: A metal halide lamp with high color rendering index, greater then 80, with substantially constant color temperature through life. The lamp arc discharge vessel has a small volume, i.e., less than 1 cc, and contains iodides of sodium, scandium, lithium, dysprosium, and thallium along with mercury, a buffer gas and scandium metal. The addition of the scandium metal does not raise the arc discharge vessel temperature and significantly reduces the color temperature decline during life.

Abstract: The amount of a metal halide to be enclosed in a generally ellipsoidal discharge space 24 within a discharge vessel 20a is set in the range 0.006-0.01 mg per unit volume (&mgr;l) of the discharge space 24. If the amount is less than 0.01 mg/&mgr;l, the deposit of metal halide 32 on the inner surface of the discharge space 20a in its lowest position midway between the narrow end portions thereof will not cause “shunting” of the arc between the electrodes 26A, 26B. As a result, the arc is effectively prevented from fizzling out after the metal halide lamp is switched on. To ensure that the metal halide lamp produces the intended luminous flux and color of light, the amount of the metal halide to be enclosed in the discharge space 24 should not be lower than 0.006 mg/&mgr;l.

Abstract: Visible light emission is obtained from a plasma containing elemental barium including neutral barium atoms and barium ion species. Neutral barium provides a strong green light emission in the center of the visible spectrum with a highly efficient conversion of electrical energy into visible light. By the selective excitation of barium ionic species, emission of visible light at longer and shorter wavelengths can be obtained simultaneously with the green emission from neutral barium, effectively providing light that is visually perceived as white. A discharge vessel contains the elemental barium and a buffer gas fill therein, and a discharge inducer is utilized to induce a desired discharge temperature and barium vapor pressure therein to produce from the barium vapor a visible light emission. The discharge can be induced utilizing a glow discharge between electrodes in the discharge vessel as well as by inductively or capacitively coupling RF energy into the plasma within the discharge vessel.

Abstract: High lumen output quartz metal halide lamps are provided which comprise a vacuum outer fill, and a silicon nitride CVD coating on the outside of the quartz arc tubes (discharge tubes). Instead of nitrogen filled outers, vacuum lamp outers are used to reduce energy loss (since heat conduction loss is reduced) and to increase lumen output. Additionally, only the outside of the arc tubes is coated with silicon nitride, without coating the metal components. This reduces or blocks sodium diffusion through the quartz walls. The silicon nitride coating also retards migration of the trace hydrogen from the lamp outer into the arc tube. At least about a 10% increase, and preferably a 15% increase in lumen output is realized by using a vacuum lamp outer instead of the nitrogen fill outer conventionally used for the traditional quartz fill lamps. The heat conduction loss is reduced and the lamp efficiency is increased significantly.

Abstract: Rare-earth halides are shown to be a replacement for scandium halides in mercury-free discharge arc lamps if modifications are made to the prior art lamp design and operating temperatures. The inventive chemical compositions of the discharge medium provide enhanced color rendition index values. In addition, it has been unexpectedly determined that during the operation of the discharge lamps, the rare earth iodides do not react significantly with the fused silica arc tube. Equally as significant, any free iodine, which is so formed, has minimal impact on the efficacy of the lamp compared to the conventional scandium iodide lamps. Therefore, the rare earth iodide-containing lamps provide longer lifetime with superior illumination characteristics than conventional discharge lamps.

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 metal-halide lamp including a discharge vessel with a ceramic wall, the discharge vessel enclosing a discharge space which contains an ionizable filling which filling contains halides of Na and Tl in addition to Hg. The ionizable filling also contains Ca and is free from rare-earth halides.

Abstract: The high-pressure discharge lamp of the present invention comprises a light-transmitting ceramic discharge vessel (1), power-supplying conductors (2), a pair of electrodes (3, 3), seals (4) made of ceramic-sealing compound, and a discharge medium. The discharge vessel has an inner volume of 0.1 cc or less. The distal ends of the electrodes are arranged so as to maintain a distance d1 of 1.0 mm or more from the inner surface of the light-transmitting vessel on a plane which is perpendicular to the axis of the light-transmitting vessel and includes the distal ends of the electrodes.

Abstract: A metal halide lamp intended to be operated on an electronic ballast includes a discharge vessel having a ceramic wall enclosing a discharge space which contains an ionizable filling comprising, in addition to Hg, a quantity of Na halide. Two electrodes have tips arranged at a mutual distance EA, the discharge vessel having an internal diameter Di at least through the distance EA, wherein EA/Di≧2.5, while the lamp has a nominal lamp voltage Vla of ≧110 V.

Abstract: A long-life, environmentally disposable high pressure sodium lamp comprising: an arc tube capable of withstanding internal wall temperatures of 1250 to 1300° C. and having electrodes sealed therein and being designed for operation at a given wattage; a discharge space within the arc tube and an arc generating and sustaining medium within the discharge space, the medium being mercury-free and containing sodium in an amount of about 0.02 mg to 0.06 mg/watt of designed operation, and xenon at a pressure of 100 to 200 Torr; mounting means supporting the arc tube within a glass outer envelope, the glass outer envelope being lead-free and arsenic-free; and an electrically conductive base closing the outer envelope and containing lead-in wires affixed to the electrodes, the lead-in wires being attached to the base by welding.

Abstract: The present invention provides a mercury-free metal halide lamp with an increased lamp operating voltage and prolonged lamp life without enclosing mercury or excessively increasing an inner pressure of an arc tube. A lamp in accordance with the present invention contains, as a content of a fill material 202, 0.04 mg of ScI3, 0.21 mg of NaI, 7 atm of Xe at room temperature, and 0.1 mg of YI3, which is an iodide of Y, Y having an ionization potential as a simple substance being 5 to 10 eV and a vapor pressure at a temperature of lamp operation being 10−5 or higher.

Abstract: A high-pressure discharge lamp includes: a quartz glass bulb; conductive elements; and a pair of electrodes. The conductive elements are airtightly sealed at sealing portions of the quartz glass bulb. Each electrode of the pair of electrodes is disposed so as to be opposite each other and connected to one of the conductive elements. The quartz glass bulb is formed as a single piece unit by using a synthetic quartz whose viscosity is about 1013 poise or more at about 1200° C.

Abstract: In a microwave-excited discharge lamp of the present invention, a rare gas 2, a mercury halide 3 as a buffer material, and a metal halide 4 as a luminous material are sealed within an discharge tube 1. This achieves a microwave-excited discharge lamp having excellent stability and a variety of light colors.

Abstract: A sealed, metal oxide, electrodeless discharge lamp having a high emission ntensity in the visible 400-700 nm range. Within the sealed container assembly of the lamp there is a source of metal atoms capable of forming a volatile oxide and a source of an oxygen containing gas. The lamp produces a plasma and volatilizes the metal into the plasma. Preferably the lamp is at a low pressure of about 20-40 torr and the metals are molybdenum or tungsten. Power is applied by inductively coupled electromagnetic radiation. A regenerative agent such as a halogen is added for recycling any deposited metal into the gas phase and to form a volatile compound with the source of metal atoms. The agent lowers the temperatures needed to volatilize the metal into the plasma. The lamp is operated by first providing energy at a low level to initiate the plasma and then supplying the metal atoms into the plasma.

Abstract: A discharge vessel with a ceramic wall encloses a discharge space in which besides a rare gas also an ionizable filling comprising at least NaI is present. Two electrodes having tips with a mutual distance EA are arranged in the discharge space which discharge vessel has an internal diameter Di over at least the electrode distance EA. The discharge space is Hg-free and the ionizable filling further comprises Zn and the electrode distance EA and the internal diameter Di comply with the relation 1.ltoreq.EA/Di.ltoreq.4.

Abstract: The present invention is directed to a metal hydrides lamp and a fill for such a lamp. The lamp chamber includes a fill of at least one metal, a buffer gas, and hydrogen and/or deuterium. When energy is provided to the fill, metal combines with the hydrogen and/or deuterium to form a molecule at an excited energy level which emits visible light when the molecule moves to a ground state energy level. The lamp may be an electrode lamp, an electrodeless lamp, a microwave lamp, or any other power source capable of imparting energy into a fill contained within a lamp chamber.

Abstract: Disclosed is a lamp apparatus designed for both bleaching teeth and curing dental restorative materials. Both bleaching and curing modes of operation may be used in at least three different power levels designated as boost, ramp, and normal. The lamp apparatus contains a incandescent xenon-halogen bulb and a dichroic reflector which focuses filtered visible light on the end of a flexible light guide which is part a handpiece for directing the transmitted light by the light guide to a tooth being treated. The lamp apparatus employs a slave microprocessor in a control panel mountable at different positions on a housing for the xenon-halogen bulb and a master microprocessor within the housing which is detachably connected to the slave microprocessor.

Abstract: A system and method for operating a dual electrode flashlamp. The method employs steps of applying an electrical potential between a pair of electrodes of the dual electrode flashlamp; and irradiating a region behind one of said electrodes with microwave energy. The system has a flashlamp bulb; a first electrode positioned at one end of the flashlamp bulb; a second electrode positioned at another end of the flashlamp bulb; and a microwave energy source positioned to direct microwave energy at the flashlamp bulb.

Abstract: The spectral energy characteristic of a discharge lamp is controlled by changing the density of the fill substance. The spectral characteristic can be shifted while substantially maintaining its shape by changing the density of the fill. A sulfur or selenium containing discharge lamp which is operated at a pressure of at least about 1 atmosphere contains a low ionization potential substance in the fill. Characteristics which are improved are one or more of spatial color uniformity, extinguishing characteristics, and bulb starting reliability. Particular substances which are added to the fill are alkali metal containing substances, III B metal containing substances, and alkaline earth metal containing substances. When light is reflected back into the bulb, the light which is re-emitted is stronger in the higher wavelengths.

Abstract: The high-pressure sodium discharge lamp of low power described here is chcterized by a very high xenon cold filling pressure of at least 1 bar. The pressure ratio to the sodium operating pressures lies between 10 and 30. Luminous efficacies of approximately 100 lm/W and more can be obtained with a lamp power of 50 to 100 W.

Abstract: Metal halide lamp radiates light with a color temperature T.sub.c of between 3900 K and 4200 K and with a general color rendering index R.sub.a .gtoreq.90. The ionizable metal halide filling comprises between 30 and 50 mole % CaI.sub.2. The lamp has a limited crest factor, and accordingly a long useful life.

Abstract: A single-tube high-watt metal halide lamp being characterized in that its fixture socket installation portions are formed at caps secured to a pair of sealing portions formed at both sides of a discharge tube, and the distance between the fixture socket installation portion and the sealing portion is set at 8.5 mm or less so as to dispose the molybdenum foil of the sealing portion close to a socket of a lighting fixture, whereby the lamp can reduce the temperatures at the ends of the sealing portions and can have a long service life.

Abstract: The spectral energy characteristic of a discharge lamp is controlled by changing the density of the fill substance. The spectral characteristic can be shifted while substantially maintaining its shape by changing the density of the fill. A sulfur or selenium containing discharge lamp which is operated at a pressure of at least about 1 atmosphere contains a low ionization potential substance in the fill. Characteristics which are improved are one or more of spatial color uniformity, extinguishing characteristics, and bulb starting reliability. Particular substances which are added to the fill are alkali metal containing substances, III B metal containing substances, and alkaline earth metal containing substances. When light is reflected back into the bulb, the light which is re-emitted is stronger in the higher wavelengths.

Abstract: An Electrodeless High Intensity Discharge (EHID) lamp for projection applications. The lamp has a small (nominal dimensions: 2 mm I.D., 3 mm O.D., 6 mm internal length) capsule, which is constricted in a mid-portion thereof. The constriction squeezes the plasma within the capsule and provides a higher power density. This in turn produces a higher luminance in the center of the arc. This focal point of the projection system is constant over the life of the lamp, owing to the fact that the system is electrodeless. The arc tube or capsule is thickened in the vicinity of the constriction to permit heat transfer through the vitreous silica (commonly called quartz). The thickening carries the heat away from the now hotter mid-portion area. This thickening cools by virtue of increasing the thermal conduction through the glass.

Abstract: A primary color lamp comprises a glass envelope with a krypton arc doped with metal halides. A cesium bromide or cesium iodide solution is included with lithium iodide (LiI) to produce red light, thallium iodide (TlI) to produce green light and indium iodide (InI) to produce blue light. The solution controls the vapor pressures of the lithium iodide (LiI), thallium iodide (TlI) and indium iodide (InI) and allows them to be balanced for light amplitude output. No mercury is used in order to eliminate a corresponding yellow light output and the filter complications that result in a system that operates on the primary colors.

Abstract: In a mercury vapor discharge lamp having an envelope of light-transmitting vitreous material and containing an inert gas and a quantity of elemental mercury at least partially convertible to soluble mercury, and first and second electrodes disposed within the envelope for establishing an arc discharge therebetween, an improvement comprising an effective amount of a nonmetallic copper-containing compound disposed in the lamp which, when the lamp is pulverized to granules and subjected to a suitable aqueous acid solution, dissolves in the aqueous acid solution, resulting in a concentration of extracted mercury less than 0.2 mg per liter of solution; and a method for reducing the amount of mercury extracted from a mercury vapor discharge lamp when the lamp is pulverized to granules and subjected to a suitable aqueous acid solution, such that the resulting concentration of extracted mercury is less than 0.