Abstract: The invention provides an arc tube with improved chromaticity and start-up characteristics that does not contain mercury, and provides a vehicle headlamp equipped with a metal halide lamp that contains no mercury in the arc tube. Among other improvements, the evaporation of low melting point metal halides is promoted and the start-up characteristics of the arc tube are improved.

Abstract: A metal halide lamp using a ceramic arc tube in which less lamp flickering occurs, the flux maintenance factor during the lifetime is high and the possibility of lamp break-off is low. The metal halide lamp includes an arc tube 1 in which iodide pellet of metal halide is filled, and a pair of electrodes are arranged in the ceramic arc tube so that the electrode coils are facing each other. The following relation is satisfied: 0.00056×W+0.061≦&agr;≦0.0056×W+1.61 where &agr; (in mm) denotes a length of the portion of the electrode bar protruding from the end face of the electrode coil and W (in Watt) denotes the lamp power.

Abstract: The discharge spacings in discharge lamps for dielectrically impeded discharges are shortened below 3 mm, as a result of which dead times of pulsed active-power injecting can be increased so strongly, for example beyond 50 ms, that the dimming properties of the discharge lamp are greatly improved.

Abstract: In a high-power dual-filament incandescent lamp for use in a reflector having an optical axis, which incandescent lamp comprises two incandescent coils which are substantially parallel to one another, which in their correct operational positions are arranged substantially parallel to the optical axis of the reflector in a lamp bulb, and which can be operated alternately, the glass bulb is arranged such that it shows a horizontal and vertical displacement relative to the optical axis of the reflector when in the correct operational position.

Abstract: A mercury-free high-intensity discharge lamp operating apparatus includes a horizontally operated high-intensity discharge lamp including an arc tube in which a luminous material is enclosed and a pair of electrodes are arranged in the arc tube; a ballast including an alternating current generation means for supplying alternating current to the pair of electrodes; and a magnetic field application means for applying in substantially vertical direction a magnetic field having a component that is substantially perpendicular to a straight line connecting heads of the pair of electrodes; wherein mercury is not included as the luminous material in the arc tube.

Abstract: In a plasma display panel, data electrodes are formed parallel to each other on a first substrate, and a selection voltage is to be applied to them. A dielectric layer covers a surface of the first substrate to include the data electrodes. Linear partitions are formed at a predetermined interval on the first substrate to be parallel to the data electrodes. A second substrate opposes the first substrate. A closed space between the first and second substrates is filled with a gas. Intersections of a pair of sustain discharge electrodes and data electrodes form matrix-like discharge cells. Stepped partitions are formed at a predetermined interval on the first substrate in a direction intersecting the linear partitions.

Abstract: A high-intensity arc lamp comprises a glass envelope with a pressurized gas atmosphere. A cathode and an anode structure are disposed within. A pointed tip of the cathode is juxtaposed by a central hole in a face of the anode and a small gap between them. Such central hole is vented away from the arc down inside the anode structure. During operation, heat from the arc at the entrance to the central hole drives a wind of xenon gas down through such vents in the anode structure.

Abstract: In a short-arc high-pressure discharge lamp (1) with a xenon fill for digital projection purposes, the separation L in mm of the two mutually facing end sections (6a, 8c) of the cathode (6) and the anode (8) when the lamp is hot is given by the relationship 0.8×P≦L≦1×P+1, where P is the lamp power in kW. Further, the diameter D of the circular-cylindrical middle section (8a) of the anode (8) in mm obeys the relationship D≧2.1×L+10.

Abstract: Light source device which includes a discharge lamp which contains at least 0.15 mg mercury per cubic millimeter of the volume of the discharge space, a pair of electrodes opposite one another to create the main discharge and spaced a distance from one another of less than or equal to 2.5 mm, and an auxiliary electrode arranged such that it does not come into contact with the discharge space for the main discharge. The light source device further including a feed circuit to feed the discharge current to the electrodes for the main discharge, and a starter which produces a high voltage between one of the electrodes of the two electrodes for the main discharge and the auxiliary discharge, such that the starter produces a voltage two to five times as high as the voltage necessary for starting the main discharge in the lamp at the room temperature state.

Abstract: A fill material 201 enclosed in an arc tube 201 with an inner diameter of 10.8 mm includes ScI3, argon, and mercury. A distance between electrodes 202 is set at 2.2 mm, and a distance between the inner wall of the arc tube 201 and the electrodes 202 is set at approximately 5.4 mm, which is approximately twice the distance between the electrodes 202. The lamp of the present invention is capable of forming thin arc and thereby achieving high luminance since only the metallic elements having an ionization potential of 6 eV or higher is contained in the fill material 207. The restriction of the short distance between the electrodes serves to stabilize arc. Scandium in the fill material serves to achieve a good color reproduction characteristic.

Abstract: Metal halide lamp includes a discharge vessel having a ceramic wall with an internal diameter Di and enclosing two electrodes whose tips are a distance EA apart, wherein EA/Di>5. The vessel has a filling comprising Hg, CeI, and LiI.

Abstract: The high-pressure discharge lamp comprises a lamp vessel (1) in which an anode (4) and a cathode (5) are disposed spaced apart by an electrode distance D of 1-2 mm, the anode (4) having a tip (9) with a blunt end surface S. The area of the end surface S in mm2 and the lamp current I in amperes satisfy a relationship according to which 0.09≦S/I≦0.16, with 3.5≦I≦8.0 amperes. The ionizable filling containing metal halide comprises an amount of mercury between 65-125 mg/cm3. The power range of the lamp is between 200 and 400 watts. The calculated power gap ratio, PGR=P/D, is over 120 W/mm. The lamp is suitable for comparatively high brightness applications and at the same time is comparatively stable and has a comparatively long life.

Abstract: The invention relates to a gas discharge lamp, in particular a high-pressure discharge lamp for use in automobiles. The invention further relates to a lighting system with at least one light source, at least one light coupling system, at least one optical waveguide, and at least one light delivery system. Such lighting systems with a central light source and a distribution of the light over optical waveguides (i.e. suitable optical fiber systems) in remote locations are particularly suitable for applications in the automobile branch. For this application, a high brightness must be available already after a short run-up time of the lamp. To provide a gas discharge lamp with a high brightness, which makes available a sufficient brightness after a short period, a gas discharge lamp is proposed with a bulb which has an ellipsoidal discharge chamber in a central location, which chamber has a surface area with a maximum value of below 2.5 cm.sup.

Abstract: A metal halide lamp comprises a light-transmitting discharge vessel having a discharge space portion, a sealed portion, and a pair of electrodes projecting into the discharge space. The discharge vessel is constructed and arranged to have a D/L ratio being in a range of about 0.25 to about 1.5 and a t/L ratio being in a range of about 0.16 to about 1.1, wherein L is an interspace of tips of the electrodes, D is a maximum inner diameter of the discharge vessel, and t is a maximum wall thickness of the discharge space portion. An ionizable filling contains a rare gas and a metal halide including at least sodium (Na) or scandium (Sc) and does not substantially include mercury (Hg). Each of conductive wires is connected electrically to the electrodes extending from the discharge vessel. The metal halide lamp may be used for a metal halide lamp apparatus or a vehicle lighting apparatus.

Abstract: A light source device including a short arc discharge lamp having a pair of opposed electrodes within a light emitting bulb of a discharge container, and a concave reflector having an optical axis arranged to coincide with a direction of an arc produced by the electrodes when the discharge lamp is activated. The electrodes are spaced from each other at a distance of 4.0 mm or less and the light emitting bulb has an inner surface and an outer surface which, at least in a specific portion, have substantially spherical surfaces with a center of curvature which is at a center of the arc. The specific portion is located in front of a critical line that passes through the light emitting bulb, the specific portion being an angle having an apex at the center of the arc. The concave reflector has an optical axis that is at least 3 sr in front of a plane which passes through the center of the arc and perpendicular to the optical axis of the concave reflector.

Abstract: A metal vapor discharge lamp includes a discharge tube comprising a translucent ceramic discharge portion that defines a discharge space in which a luminous metal is sealed, slender tube portions provided on both ends of the discharge portion, a pair of electrodes provided with coils at the tips thereof, electrode supports that support the electrodes at one end thereof and extend all the way to the ends of the slender tube portions on the side opposite to the discharge space at the other end thereof, and a sealant for sealing the ends of the slender tube portions on the side opposite to the discharge space so as to attach the electrode supports to the inner surfaces of the slender tube portions, in which X>0.0056P+0.394 is satisfied, where P is a lamp power (W) and X is a distance (mm) from the ends of the coils on the side of the slender tube portions to the ends of the slender tube portions on the side of the discharge space.

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: The invention relates to a metal halide lamp which is provided with a discharge vessel having a ceramic wall and enclosing a discharge space. Two electrodes having tips at a mutual distance EA are positioned in the discharge space, which contains besides Xe also an ionizable filling with NaI and CeI3. The discharge vessel has an internal diameter Di at least over the length EA. According to the invention it holds that Di<1.4 mm and also that the relation EA/Di<5 is complied with.

Abstract: A high brightness discharge light source having improved thermal balance characteristics includes a lamp envelope having an arc chamber formed therein and a pair of electrodes extending into opposite ends of the arc chamber so as to be displaced from one another by a distance of no greater than 4 mm. A fill disposed within the arc chamber is excited to a discharge state upon the introduction of an excitation energy coupled through the pair of electrodes. The light source is operated vertically so that one of the electrodes is disposed at the top region and the other electrode is disposed at the bottom region of the arc chamber. The arc chamber is formed having a diameter dimension which is just larger than the spacing between the electrodes, and a height dimension which is approximately twice the diameter dimension. The diameter dimension is substantially uniform along the length of the arc chamber.

Abstract: A high-capacity UV radiation apparatus, especially a high-capacity mercury low-pressure tube, for vertical applications, including a discharge chamber that is formed by a cylindrical flask made of UV-transmissive glass and that contains a filling gas, a first or a second electrode, and electrical connections leading to the outside, with an electrode holder being arranged in the area of each flask. One electrode holder is considerably longer than the other electrode holder. The temperature of the cold spot in the dead electrode space is therefore reduced on the longer electrode holder, with the steam pressure or efficiency curve of the radiation apparatus being optimized with a vertical arrangement of the radiation apparatus with the long electrode holder in the upper position. In order to ensure correct assembly, the apparatus contains a marking on at least one flask end, which provides information about the length of the respective electrode holder.

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 discharge lamp (1) including a tubular discharge vessel (2), filled with inert gas and, optionally, a fluorescent layer, having at least three elongated electrodes (3, 4, 5) arranged parallel to the longitudinal axis of the tubular discharge vessel (2). The electrodes are arranged in such a manner that the relationship s a ≥ 0.1 is satisfied, wherein s is the maximum spacing between an imaginary connecting line of an electrode pair and the most closely neighboring point on the wall of the tubular discharge vessel, and a is the mutual spacing between the electrodes of such electrode pair. A higher luminous density is achieved in this way. The lamp is particularly advantageous for a pulsed, dielectrically impeded discharge.

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 metal halide lamp includes a pair of electrodes with a spacing of 0.5 to 1.5 mm therebetween, an envelope enclosing the pair of electrodes, and at least one metal halide, other than a mercury halide, that is encapsulated in the envelope in an amount of from 0.04 to 0.3 mg/cc, wherein the metal halide lamp operates in a power range from 75 to 270 watts per millimeter across the spacing between the pair of electrodes.

Abstract: Metal halide lamp includes a discharge vessel having a ceramic wall with an internal diameter Di and enclosing two electrodes whose tips are a distance EA apart, wherein EA/Di>5. The vessel has a filling comprising Hg, CeI, and LiI.

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: In a metal halide lamp which includes a discharge tube (2) retaining a fill of mercury and at least one metal halide added as a luminous material, an energy density of the arc discharge portion (3) represented by a product E.times.j is in the range of 70.0.ltoreq.E.times.j.ltoreq.150.0 (VA/mm.sup.3) where E=V/d, j=I/S, assuming that I is a lamp current in amperes with a lamp voltage of V volts applied between the paired discharge electrodes in a stable lighting condition of the lamp and that each of the electrodes has a tip face (1a, 1a') of which a cut area in section is S mm.sup.2 and the gap distance is d in millimeters, and thus a high luminous flux retention rate and high luminance of an arc discharge portion can be accomplished with a longer life of the lamp, suppressing a lamp voltage varying rate, and avoiding a change in color temperature, which remarkably improves additional merits when in utilization as a light source in various display apparatuses such as optical projection systems.

Abstract: A plurality of discharge electrodes (23), (24) are formed on a first substrate (22) at an interval between the adjacent electrodes set to 50 .mu.m or smaller. A fluorescent layer (26) is formed on a second substrate (25 opposed to the first substrate (22). A sealed vessel (28) is formed by locating the first and second substrates (22) and (25) so that the electrodes (23) and (24) and the fluorescent layer (26) should be located on their inner sides. A predetermined gas is introduced in the sealed vessel (28) so that a pressure of the introduced gas should be within the range from 0.8 to 3.0 atmospheric pressure. Ultraviolet rays are produced by plasma discharge and make the fluorescent layer (26) emit light which is employed as illumination light.

Abstract: A metal halide lamp with a distance of less than 3.0 mm between the electrodes, in which in the hermetically sealed portion no cracks occur, which can be produced without difficulty, and which enables advantageous operation is achieved with a halide lamp in which an arc tube made of quartz glass contains a cathode and an anode spaced from each other at a distance of less than or equal to 2.9 mm together with mercury and metal halides, and which is operated with a nominal wattage range of from 100 to 400 W using direct current, by causing the ratio D/H to be greater than or equal to 1.9 when D is the maximum inside diameter in millimeters in a direction which orthogonally intersects the axial direction of the electrodes in the discharge space and H is the length of the cathode projecting within the discharge space, also in millimeters.

Abstract: An integrated dual day night backlight includes a flat channel light source with an auxiliary night light source suitably filtered to remove infrared components from the illumination. In alternative embodiments, the night light can be a separate bulb or it can be separate light channels within the flat channel source. The night illumination is directed through the edge of the light transmissive face plate that covers the main or day channel. The light directing means can be an inner reflecting surface of the face plate or can be a separate reflective element that redirects the illumination from the night channel through the edge of the transmissive face plate.

Abstract: Metal halide lamp with ceramic discharge vessel having electrodes with spacing EA, internal diameter Di, and EA/Di>5. Ionizable filling comprises NaI and CeI.sub.3, and a coldest spot temperature of 1100-1500 K is achieved.

Abstract: The invention relates to a high-pressure metal halide lamp provided with a discharge vessel with a ceramic wall enclosing a discharge space. The vessel has a cylindrical portion of internal diameter ID which is closed off at either end by end wall portions which form end faces of the discharge space. At least two electrodes are arranged in the discharge vessel, whose respective tips have an interspacing EA such that ##EQU1## The electrodes have lead-throughs which are enclosed in ceramic closing plugs and are connected thereto in a gastight manner by means of ceramic glazing joints.According to the invention, the rated lamp power is at most 100 W, and an electrode tip lies substantially in the adjacent end face. A closing plug is fastened in the relevant end wall portion in a gastight manner at a distance from the end face.

Abstract: A mercury lamp of the short arc type in which tantalum can absorb impurity gases to a sufficient degree even if the inside of the arc tube reaches a high temperature is achieved by providing an arc tube, within which mercury and an inert gas are encapsulated, with a pair of electrodes disposed opposite each other within the arc tube, each of the electrodes being supported by a respective terminal post, tantalum being provided on the terminal post of one of the electrodes, and by ensuring that both of the relationships (D2/D1)>1.3 and the relationship 0.2.ltoreq.(D2/D1).sup.2 /L.ltoreq.0.5 are satisfied at the same time, where D1 is an outer diameter of the terminal post in millimeters, D2 is an outer diameter of the electrode supported by the respective terminal post in millimeters, and L is a distance between a tip of the electrode on which the tantalum is provided and the tantalum on the terminal post of that electrode.

Abstract: A metal halide arc discharge lamp rated for not more than 150 watts and 100 volts and which can be operated in either a horizontal or vertical position without a significant change in color temperature or lumen output has an ellipsoidal arc chamber mounted within a nitrogen-containing outer envelope. The arc chamber contains a pair of electrodes, mercury and sodium and scandium iodides and is coated at each end with a heat reflective coating. The chamber aspect ratio, electrode insertion length, metal halide density, coating length and wall loading are defined within narrow ranges.

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 discharge lamp in which vaporization and melting of a cathode tip are prevented and which has stable luminous operation over a long is achieved according to the invention by the fact that the discharge lamp has a cathode in which a sintered body made of a powdered metal with a high melting point and a powdered emitter material is inserted in the tip, and the relationship:(-0.002d+0.01).ltoreq.D/W.ltoreq.(-0.002d+0.04)is fulfilled, where D is an outside diameter of the sintered body in millimeters (mm), W is a lamp input power in watts (w) and d is a distance between the anode and cathode in millimeters (mm). Furthermore, these benefits are achieved according to the invention by encapsulating mercury in an amount of 10 mg to 80 mg/cc of fluorescent tube internal volume and inert gas with at least 2 atm air pressure (at a reference temperature of 25.degree. C.).

Abstract: An emission device which operates a cadmium lamp with a light intensity sufficient for used in industrial applications is achieved by an emission device having a cadmium lamp with a fluorescent tube within which a cathode and an anode are space a small distance apart and a buffer gas for easier initiation of luminous operation and metallic cadmium in an amount per unit volume of the fluorescent tube of 1.times.10.sup.-4 g/cm.sup.3 to 3.times.10.sup.-3 g/cm.sup.3 are encapsulated, and a power source device for supplying an electrical input between the cathode and the anode in an electrical input range from 0.5 kW to 5.0 kW with the condition:6.03+2.79 W.ltoreq.r.ltoreq.40being satisfied, where the electrical input of the power source device into the cadmium lamp in steady-state luminous operation is W (kW) and the maximum inside radius of the fluorescent tube is r (mm).

Abstract: A lamp device having one-piece arrangement of a metal halide lamp and a reflector which has a front cover in which a small, compact shape for installation of a halogen lamp can be obtained, which has characteristics of high efficiency, good color reproduction and high power. The lamp has a unidirectional base and a unidirectional sealed end which is configured such that it is surrounded by a front cover and a reflector.

Abstract: A discharge lamp uses resonance lines which are emitted by ions in an excitation state and has a high short wave ultraviolet ray output. The lamp is provided with a pair of electrodes, having a reciprocal spacing of equal to or smaller than 12 mm, and is of the electrode-stable type. As the major emission material, cadmium is encapsulated in a quantity permitting a partial pressure P in operation of 3.times.10.sup.3 Pa to 1.3.times.10.sup.5 Pa. The lighting operation is performed in a state in which a lamp current J.sub.L fulfills the following condition (a):0.7<J.sub.L /P.sup.1/4 <15.0. Condition (a)As an alternate major emission material, zinc can be encapsulated in a quantity permitting a partial pressure P in operation of 1.times.10.sup.3 Pa to 0.3.times.10.sup.5 Pa ant the lighting operation is performed in a state in which a lamp current J.sub.L fulfills the following condition (b):0.7<J.sub.L /P.sup.1/4 <16.9.

Abstract: In a flat display device, for example, a luminescent display a spacer structure (5) is provided between two substrates (1, 3). To this end a mask (9, 15) consisting, if necessary, of a plurality of layers is incorporated in a photosensitive material (8, 13). After exposure, development and removal of the mask, the desired spacer structure is obtained.

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 metal halide arc discharge lamp includes a sealed light-transmissive outer jacket, a light-transmissive shroud located within the outer jacket and an arc tube assembly located within the shroud. The arc tube assembly includes an arc tube, electrodes mounted within the arc tube and a fill material for supporting an arc discharge. The electrodes have a spacing such that an electric field in a range of about 60 to 95 volts per centimeter is established between the electrodes. The diameter of the arc tube and the spacing of the electrodes are selected to provide an arc having an arc diameter to arc length ratio in a range of about 1.6 to 1.8. The fill material includes mercury, sodium iodide, scandium tri-iodide and a rare gas, and may include lithium iodide. The lamp exhibits a high color rendering index, high lumen output and high color temperature.

Abstract: A glow discharge starter having an hermetically sealed envelope containing an ionizable medium, a bimetallic electrode including a first bimetallic element having a curved portion and a free end, and a counter electrode. A first discharge gap having a predetermined spacing is formed between the free end of the first bimetallic element and the counter electrode. The starter includes a second bimetallic element having an end secured to the counter electrode. A portion of the second bimetallic element is positioned adjacent the curved portion of the first bimetallic element such that a second discharge gap having a predetermined spacing is formed therebetween. In the event that the starter encounters a dc current of the wrong polarity, a portion of the second bimetallic element contacts the first bimetallic element so as to extinguish the arc discharge and prevent electrode damage.

Abstract: Asymmetric discharge electrode means are provided for a metal halide lamp enabling improved operation at acoustic frequencies. A xenon-metal halide lamp employing such improved discharge electrode means is disclosed together with a reflector lamp unit employing such lamp construction for its light source.

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: 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 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.

Abstract: A glow discharge lamp includes a light-transmitting envelope containing a noble gas fill material. An anode electrode and a cathode electrode are spacedly located within the envelope. The anode electrode includes a single wire having a convoluted portion adjacent the cathode electrode and lying in a plane parallel to a plane intersecting the cathode electrode and a pair of lead-in wires supporting the cathode electrode. The improved anode construction results in an increase in both light output and lamp efficacy.

Abstract: A gas-filled discharge tube for voltage control particularly for the series gap of the ignition system of an automotive spark-ignition engine. The gas-filled discharge tube is capable of operating stably at a sufficiently high discharge inception voltage, requires a sufficiently low discharge sustaining voltage and is capable of accurately controlling the ignition timing of the automotive spark-ignition engine regardless of the variation of the output voltage of the ignition coil of the ignition system. The gas-filled discharge tube is provided with discharge electrodes meeting requirements that the opposite surfaces of the discharge electrodes are substantially flat, the discharge electrodes have no sharp edge, and the product of the diameter of the discharge electrodes and the distance between the discharge electrode is 20 mm.sup.2 or below. The gas-filled discharge tube is filled with a mixed gas having a composition of 50% by volume or below in nitrogen content and 50% or above in argon content.

Abstract: The invention relates to a high-pressure sodium discharge lamp provided with a discharge vessel having a ceramic wall and enclosed with intervening space by an outer bulb. The discharge vessel is provided with two electrodes whose respective tips have a mutual distance D. The discharge vessel has a substantially circular cross-section with an interior diameter d.sub.i over the distance D. Under nominal operating conditions, according to the invention, the wall has a wall load of at least 60 W/cm.sup.2, the space between the outer bulb and the discharge vessel contains a gas filling, and D/d.sub.i being >6.