Abstract: 845 A method of producing a ceramic-metal-halide (CMH) discharge lamp having a monolithic seal between a sapphire (single crystal alumina) arc tube and a polycrystalline alumina end cap. The method includes the steps of providing an arc tube of fully dense sapphire and providing an end cap made of unsintered compressed polycrystalline alumina powder. The end cap is heated until it is presintered to remove organic binder material at a low temperature relative to the sintering temperature. The presintered end cap is placed on an end portion of the arc tube to form an interface therebetween. The assembled presintered end cap and arc tube are then heated to the sintering temperature wherein the end cap is fully sintered onto the arc tube and the sapphire tube grows into the end cap. A monolithic seal is formed at the previous interface between the end cap and the arc tube as the sapphire tube grows into the polycrystalline alumina end cap.

Abstract: An arc discharge tube has electrodes supported by hollow electrode support tubes at each end. A slot is formed in the electrode support tube. One edge of the slot is depressed inwardly to form a concave surface. The slot is located adjacent to the end cap of the arc tube and provides access to the interior of the electrode support tube. After the electrode assembly is sealed into one end of the arc tube, amalgam particles are dispensed into the arc tube. The arc tube is agitated rapidly, causing the amalgam particles to pass through the slot and drop into the interior of the electrode support tube. The amalgam particles are isolated from heat during sealing of the other end of the arc tube.

Abstract: A fluorescent lamp wherein the replaceable gas discharge bulb assembly is equipped with parallel pins which are formed directly in the bulb assembly. Due to this modular construction, the bulbs can be used in a variety of applications.

Abstract: An electrodeless discharge lamp has an arc tube which seals at least rare gas and one of luminous metal and metal halide thereinto, an opening of the arc tube being vacuum-sealed with at least molten glass, and an sealing unit of the arc tube being placed outside a cavity which supplies excitation energy to make said electrodeless discharge lamp emit a light.

Abstract: A method of making a ceramic arc tube for a metal halide lamp comprises the steps of forming as an integral unit a hollow body having one open end and a substantially closed end. The substantially closed end includes an outwardly extending capillary tube having an electrode receiving aperture therein that communicates with the hollow body. An end cap is then formed for closing the open end. The end cap comprises an annular portion and an extending capillary tube, The end cap is fitted into the open end of the hollow body to form a pre-assembly. The pre-assembly is then fired to seal the end cap to the hollow body to form an assembly and the assembly is subsequently fired to sinter the same.

Abstract: A quartz glass vessel having mutually opposed first and second neck-shaped portions is heated over the first neck-shaped portion while flushing the vessel with gas, then pinched over an external current wire and collapsed over a metal foil by means of reduced pressure to form a seal. The second neck-shaped portion may also be collapsed over a metal foil by reduced pressure in the lamp vessel to form a seal. The seals are preferably shaped to form flat external surfaces.

Abstract: A surface mount assembly. The assembly includes an elongated sealed envelope, such as an incandescent lamp with a filament positioned in the envelope, first and second leads extending from the spaced ends of the envelope and a metal material applied to the second leads. The leads and metal are configured to form a pair of electrically conductive mounting members at the ends of the envelope for mounting the envelope to a circuit board.

Abstract: The low pressure sodium discharge lamp has a discharge vessel (1) having pinch seals (2) through which current conductors (4) extend towards electrodes (3) inside the discharge vessel (1). The current conductors (4) each have a first glass coating (5), which extends from inside a pinch seal (2) into the discharge vessel (1) and a second lime glass coating (6) abutting the first (5) and extending to outside the discharge vessel (1). A new first sodium resistant glass coating (5), which is substantially devoid of borate, is defined.

Abstract: A high intensity discharge lamp with a heat treated inner electrode rod has been found to form an advantageous crack pattern. As a result seal failures have been reduced and lamp life increased.

Abstract: The electric lamp has a glass lamp vessel (1) having seals (3) from which an external metal wire (6) extends. A bare corrosion resistant contact wire (7), having a specific resistance of less than 0.8 .mu..OMEGA.m and a hardness of 50-300 HV is welded, e.g. butt-welded to the external metal wire (6). The contact wire (7) has an axial free end portion (8). An transversally extending intermediate portion (9) may be present between the seal and the free-end portion (8). The lamp allows secure electrical connections to a luminaire easily and rapidly to be made.

Abstract: A discharge lamp arc tube comprises: a glass tube having a linear extension portion, a closed glass bulb, and pinch seal portions at both sides of the closed glass bulb; and electrode assemblies, each having an electrode rod, a molybdenum foil and a lead wire integrally series-connected, the molybdenum foil having oxide films thereon, wherein the electrode assemblies are inserted into the glass tube and pinch-sealed such that the molybdenum foils are positioned at the respective pinch seal portions.

Abstract: A medium pressure quartz lamp for arc discharge illumination, includes a quartz envelope having opposite electrode ends with an electrode unit sealably attached to each of the opposite electrode ends. Each of the electrode units includes an electrode rod extending into the envelope and a platform physically attached to the rod. The platform has a melting point of at least 1,000.degree. C. The electrode units also include at least one conductive, elongated metal foil which has a first end and a second end. The conductive elongated metal foil(s) are attached at their first end to the platform and attached at their second end to a terminal connector. Preferably, plural foils are utilized with a single platform attached to the electrode rod at their first ends and attached to a plurality of terminal connectors a their second ends.

Abstract: The invention relates to an electric lamp provided with a body which radiates light in the operational state of the lamp and which is enclosed with intervening space by an outer lamp envelope which is provided at one end with a stemtube with a pinch and which supports a lamp cap shell, through which pinch current lead-through conductors extend, each current lead through conductor being connected to a contact point of the lamp cap shell via an external conductor. According to the invention, each of the current lead-through conductors and the accompanying external conductors is provided with a moisture-repelling coating at least at the area of a mutual welded joint.

Abstract: A sealing structure for a light-emitting bulb assembly includes a closure, having a core which serves as an electrode for sealing an open end of a bulb. The closure includes a bulb-side region disposed adjacent to the open end of the bulb and made of a compositional ingredient having a coefficient of thermal expansion which is substantially the same as that of the bulb, a core-side region disposed adjacent to the core and made of a compositional ingredient having a coefficient of thermal expansion which is substantially the same as that of the core, and an intermediate region disposed between the bulb-side region and the core-side region and made of a compositional ingredient having compositional proportions adjusted such that a coefficient of thermal expansion thereof varies gradually from the coefficient of thermal expansion of the bulb-side region toward the coefficient of thermal expansion of the core-side region.

Abstract: The invention relates to a high-pressure discharge lamp provided with a discharge vessel which encloses a discharge space, which has a ceramic wall, and which is sealed at one end by means of a projecting ceramic plug which encloses with clearance a current supply conductor to an electrode arranged in the discharge vessel and is connected to said conductor adjacent an end facing away from the discharge space in a gastight manner by means of a melting-ceramic connection. According to the invention, at least an end portion of the ceramic plug situated near the end facing away from the discharge space is impermeable to light.

Abstract: To provide a tight seal for a fill bore in the wall or an end plug of a dharge vessel for high-pressure discharge lamps, a fill bore is provided either through the wall--in the region of the plug--or through a plug, and the fill bore is then closed by a stopper in combination with a melt sealing material, which is so chosen that the sealing material and plug-like member combination provide a minimum of sealing material exposed to the fill in the discharge volume. The fill in the discharge volume of the discharge vessel is ionizable and, for example containing halides, is highly corrosive to the sealing material. The lamp can be made by inserting a stopper into the filling bore, applying, with the stopper in place in the filling bore, sealing material to the outer end of the filling bore, and heating the portion of the discharge vessel to liquefying temperature of the sealing material to liquefy the sealing material and hence close off the fill bore.

Abstract: A metal halide lamp comprises a sealed tube containing mercury vapor and halide, and electrodes extending to a center of the sealed tube, supported by sealed portions at both ends of the sealed tube. A notch extending in a direction perpendicular to an axis of the electrode is formed in each electrode. A transverse cross sectional area of a portion where the notch is formed is smaller than the transverse cross sectional area of another portions and functions as a heat dam portion for damming heat. Accordingly, temperature of a proximal portion from the heat dam portion to the support portion is lower than that of the same portion of the conventional electrode, and temperature of a distal end portion is higher than that of the same portion of the conventional electrode. Thus, formation of low-melting alloy due to reaction of the proximal portion of the electrode and the metal halide can be suppressed.

Abstract: A lamp has a light transmissive glass envelope which includes a light source chamber. At least one glass extension is affixed to the light source chamber and has a sealing area surrounding a portion of it. A patterned metal foil is affixed to and surrounds the sealing area and a glass shroud surrounds at least the light source chamber and has an end sealed to the metal foil.

Abstract: A vacuum-tight seal, particularly for an arc tube or discharge vessel for a metal halide or sodium high-pressure discharge lamp, is made by forming the arc tube of transparent ceramic, typically Al.sub.2 O.sub.3, having two open ends, into which connecting plugs (3), with central openings, are sealed. Open metal tubes (4) fitting into the openings of the plugs (3) are then vacuum-tightly sintered therein. An electrode system (5, 10, 10'), forming a subassembly with a current supply lead or lead-through (6, 11, 14, 15, 20, 24) is provided, having an outer diameter fitting into the metal tube.

Abstract: To provide an effective seal for a metal-halide discharge lamp having a ceramic discharge vessel (4), the seal is formed in multiple parts, in which a first part, adjacent the interior or discharge side of the vessel, includes a melt component (14a) which is highly resistant to attack by metal halides within the fill of the lamp. It may contain only 0-12%, by weight, of SiO.sub.2 and has a high melting point, in the order of between 1500.degree.-1700.degree. C. The melt-in region remote from the discharge side is melt-sealed by a vitreous composition (14b), devoid of pores, voids, bubbles, fissures or cracks, to form an effective, vacuum-tight seal, and protected from attack by the metal halides by the mechanically less stable seal in the first zone. The second composition has a much lower melting point, for example in the order of between 1200.degree.-1400.degree. C., and has 20-40% SiO.sub.2.

Abstract: The electric lamp has a lamp vessel (1) provided with a pinch seal (4) which is H-shaped in cross sections. Metal foils (6), to which inner (8) and outer conductors (7) are connected to constitute current supply conductors (5), are embedded in the pinch seal (4). The metal foils (6) are each located in a respective plane parallel to the axis (3) of the lamp vessel (1) in a respective leg (4') of the H. This allows for a relatively large distance between the current supply conductors, although the pinch seal may have relatively small outer dimensions.

Abstract: In the low-pressure sodium discharge lamp the current conductors (3) have a first (4) and a second glass coating (6). The first coating (5) of borate glass extends from inside the discharge vessel (1) through a pinch seal (4). The second coating (6) of lime glass envelopes the first one (5) within the pinch seal (4) and extends to outside the discharge vessel (4). The occurrence of cracks in the pinch seal is thereby obviated.

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

Abstract: A lamp inlead assembly for a light source having a lamp envelope with at least one end region in which the lamp inlead assembly is sealably disposed includes and outer lead wire member to which power to the light source is coupled, an inner lead wire member to which the light generating device is connected, whether incandescent or discharge, and a thin foil member disposed therebetween on which the inner and outer lead wire members are fixedly secured. The thin foil member is constructed of molybdenum and is essentially uniform in thickness throughout.

Abstract: Alumina arc tube sealing members including a highly pure, fine alumina doped with yttrium oxide, and magnesium oxide. The sealing members are used in the formation of sintered hermetic seals to a green, prefired, or fully sintered translucent alumina arc tube and niobium electrical feedthrough assemblies with or without the use of sealing frits or brazing alloys.

Abstract: A high-pressure discharge lamp of the invention includes a ceramic discharge vessel (10) in which a first and a second electrode (40a, 40b) are arranged and which encloses a discharge space (11 ) which is provided with a filling containing a metal halide. The discharge vessel (10) has a central zone (20) between the electrodes (40a, 40b) and a first and a second cylindrical end zone (30a, 30b) which each surround a current supply conductor (50a, 50b) connected to a respective electrode (40a, 40b). At least the first end zone (30a) has a diameter smaller than the smallest diameter of the central zone (20). The current supply conductor (50a) through the first end zone (30a) has a halide resistant portion (51a) which faces the discharge space (11) and a portion (52a) permeable to hydrogen and oxygen and facing away from the discharge space (11).

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

Abstract: The electric lamp has a lamp vessel (1) having seals (4, 5) onto which respective bases (20, 21) are secured. Each base comprises a cylindrical insulator body (22) in a free end of which a contact member (30) is accommodated, having a contact face (31) and a protruding portion (33) which has a connection area (32) to which a current supply conductor (8) of the lamp is secured. The contact member (30) is a body made from metal foil.

Abstract: A high pressure discharge lamp includes a pair of arc tubes connected electrically in parallel within an outer envelope, which includes a lamp stem having a pair of stem conductors entering the lamp envelope in a common plane. The arc tubes include conductive feed-throughs at each end thereof. A lamp frame supports the arc tubes in a plane parallel with the stem conductors and is welded directly to each of the feed-throughs with all welds in a common plane with the welds between the frame and the stem conductors. The frame includes a resiliently deformable transverse member which allows for independent changes in length of the arc tubes during lamp operation due to thermal expansion/contraction. The frame is free of slip fit connections with the feed-throughs and free of additional conductive straps connected to the feed-throughs.

Abstract: A gas-filled discharge tube includes a tubular body formed of an electrically insulating material, and has engaging portions respectively at opposite ends thereof. A pair of electrode bases are provided; at least one of the electrode bases is formed of an electrically conducting thin metal sheet, airtightly adhered to the respective open ends. A pair of discharge electrodes are provided; the discharge electrodes have flange portions which are engaged with the respective engaging portions and sandwiched between the tubular body and the respective electrode bases. One of the electrode bases is formed with a gas filling bore by a laser beam for filling an inert gas. The gas filling bore is welded by the laser beam after the inert gas is filled in the tubular body, so as to seal and enclose the inert gas therein.

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

Abstract: An electrode feedthrough assembly for a ceramic arc tube of the type used in high pressure sodium arc lamps. The electrode feedthrough assembly is particularly useful in an external reservoir arc tube wherein an interior region of a feedthrough tube is utilized as a reservoir for the lamp fill material. The electrode feedthrough assembly includes a feedthrough tube, an electrode assembly attached to the feedthrough tube and a connection wire. The feedthrough tube has a closed end external to the arc tube. The feedthrough tube and the closed end thereof are formed in a single process, preferably by deep drawing, without welding, crimping or fusing. Passages to the interior of the feedthrough tube are provided by crimping the electrode support rod to the feedthrough tube with a six jaw crimping arrangement wherein two of the crimping jaws are shorter than the other four. The connection wire is attached to the feedthrough tube and includes a portion on the axis of the tube.

Abstract: The invention relates to a sealing composition suitable for bonding yttria or alumina ceramic members, or bonding refractory metals to the ceramics. The sealing composition has, in mole percent, about 0.5 to 40 percent yttria, about 45 to 65 percent alumina, up to 10 mole percent strontia, and the balance substantially calcia.

Abstract: A tubular electric lamp has lamp bases each consisting of an electrically insulative sleeve and conductive contact mounted therein. The sleeve has a first abutment which buts against the seal, a second abutment against which the conductive contact is seated, and an access port located axially between the first and second abutments. With the contact seated against the second abutment and the sleeve mounted over the current conductor and butted against the seal, the current conductor and a projection of the conductive contact extend axially past the access port. The conductive contact is welded and/or crimped to the conductive contact through the access port with the contact seated against the second abutment and the first abutment butted against the seal, fixing the sleeve between the contact and the seal.

Abstract: An arc tube for a high pressure metal vapor discharge lamp is provided. The arc tube of the present invention comprises a tubular ceramic envelope; a chemical fill within said envelope; a seal button at each end of said envelope; said seal button having an aperture therethrough for receiving a feedthrough member; a feedthrough member having an electrode projecting therefrom passing through said seal button aperture and being oriented such that the electrode projects into said tubular ceramic envelope, said feedthrough member being sealed into said seal button by means of a fritless seal between said seal button and said feedthrough; and sealing frit material sealing said seal buttons into the ends of said tubular ceramic envelope. A method for fabricating the above-described arc tube and high pressure metal vapor discharge lamp including the above-described arc tube is also provided.

Abstract: A miniature incandescent lamp assembly has an elongated substantially cylindrical glass envelope having a first end and a second end. A substantially cylindrical first metal end member seals the first end of the glass envelope with a seal of substantially cylindrical configuration where the glass of the envelope is in glass-to-metal contact with the first metal end member. A substantially cylindrical second metal end member seals the second end of the glass envelope with another seal of substantially cylindrical configuration. In this seal also, the glass of the envelope is in glass-to-metal contact with the second metal end member. An incandescent filament is disposed between the first and second metal end members within the interior of the glass envelope in electrical contact with the first and second metal end members. Each of the first and second metal end members has a metal cap attached to the outside of the glass envelope, with the metal caps being larger in diameter than the glass envelope.

Abstract: A miniature surface mount style lamp is disclosed which can be assembled relatively quickly, easily and inexpensively. A pair of closed metal end caps are conductively adhered to the opposed ends of a bulb envelope having a pair of exposed filament leads protruding from either end. In some embodiments, the filament leads are in physical contact with the end caps. In other embodiments, the electrical connection between the end caps and the filament leads is provided only by the conductive adhesive.

Abstract: A flashlamp provides a ruggedized yet simple-to-manufacture construction capable of operating at high average output power over a long life. The flashlamp construction includes a glass tube (12) with an electrode assembly (24) detachably secured to each end. The electrode assembly includes an end cap (26) to which an electrode support (28) is attached, with a first end (32) of the electrode support protruding inside of the glass tube, and a second end (44) of the electrode support protruding outside of the glass tube. The electrode support (28) is made from a suitable electrical conductor. An electrode (34) is threaded onto the first end of the electrode support (28) without the use of brazing or other attachment techniques that might introduce impurities. An electrode lug (36) is attached to or near the second end of the electrode support, outside of the glass tube, and provides a means for making electrical contact with the electrode (34).

Abstract: The discharge tube has an insulating tube formed into a hollow cylinder with one end open and the other closed. An anode electrode, which is formed as a flanged electrode, is hermetically fitted to the open end of the insulating tube and a cathode electrode, which is formed as a bar electrode, is embedded in the closed end of the insulating tube so that only the front end surface of the bar electrode faces the interior of the insulating tube. This construction allows no redundant space within the insulating tube other than the dishcarge space, so that the discharge tube can be minimized in size. This construction also permits a discharge only between the front end of the bar electrode and the inner end of the flanged electrode, stabilizing the electron emission passage or discharge path and therefore the discharge voltage.

Abstract: The high pressure discharge lamp has containment structure in the outer envelope which encloses the discharge vessel. The containment structure consists of a glass cylindrical sleeve closed at its ends by a metal plate. The plates, the cylindrical sleeve and the discharge vessel are combined as a subassembly. The metal plates are provided with tongues bearing on the glass cylindrical sleeve and the outer envelope. The lamp has a flexible conductor which extends from the current lead-through conductor remote from the stem to the lamp stem and bears on the outer envelope. The containment structure prevents failure of the outer lamp envelope in the event of explosive failure of the discharge vessel.

Abstract: Disclosed herein is a discharge lamp comprising a light-emitting tubing equipped with an envelope having side tube portions of a graded seal structure; and cylindrical bases fitted on the side tube portions to cover the outer end portions of the side tube portions and fixed with a cement on the side tube portions so as to define radiating spaces. In this discharge lamp, cement-controlling members for avoiding the outflow of the cement filled in a gap between the outer peripheral surface of each side tube portion and the base into the radiating space are respectively provided in the bases. The cement-controlling member is composed of a first ring portion which stops up the gap, a second ring portion held in contact with the inner bottom surface of the base and a connecting portion. The outflow of the cement into the radiating space is prevented so that the base can be fixed strongly on the side tube portion.

Abstract: A high pressure metal halide discharge lamp having a containment sleeve closed by a pair of metallic end caps for containing arc tube fragments in the event of explosive failure of the arc tube. Insulators secured in the end caps electrically insulate the arc tube lead-throughs from the end caps. Metallic tubes fixed on the lead-throughs butt against the insulators to secure the arc tube between the end caps and hold the end caps against the containment sleeve. Photoelectric emission from the end caps is avoided by electrically isolating the end caps or by providing a dielectric coating on end cap surfaces exposed to ultraviolet radiation.

Abstract: A metal vapor discharge lamp has a luminous tube constituted by a translucent ceramic tube member, end caps hermetically fixed to both ends of the translucent ceramic tube member, and electric supporting tubes hermetically inserted into respective end caps. One of the electrode supporting tubes serves also as an exhaust tube for evacuation and also as a reservoir for a metal charged in the luminous tube. The outer end extremity of this electrode supporting tube is hermetically sealed through fusion by application of heat. This hermetic seal is formed by fusing the end of the electrode supporting tube by application of heat thereto, while keeping a heat-shielding/absorbing plate held in close contact with the electrode supporting tube.

Abstract: A ceramic envelope device for an HID lamp, wherein a translucent ceramic arc tube is closed at opposite end sections thereof by respective end caps which support respective discharge electrodes on their inner surfaces. At least one of the opposite end sections of the arc tube is sealed with a sealing layer, and each of the sealed end section of the tube includes a first axial portion having a first inside diameter, and a second axial portion having a second inside diameter smaller than the first inside diameter and disposed axially inwardly of the first axial portion. The first and second axial portions define an annular shoulder surface radially inwardly extending between the first and second inside diameters. The first axial portion preferably has a cylindrical wall thickness of 1.0-1.5 mm, and the annular shoulder surface preferably has a radial width of 0.2-0.8 mm. The sealing layer is interposed between the first axial portion of the arc tube and the corresponding end cap.

Abstract: A high pressure sodium lamp including a light permeable arc tube and an electrode extending into the arc tube via a central aperture provided in the arc tube. The electrode is supported in the aperture by means of a glass solder sealing composition. Sodium amalgam is seated in the arc tube and condensed at a corner thereof. To prevent sodium amalgam condensed at the corner of the arc tube from contacting the glass solder filled in the central aperture of the arc tube, sodium amalgam including sodium of 10-30 (wt %) is sealed in the arc tube at a prescribed volume V (mm.sup.3) which substantially satisfies the following relationship: ##EQU1## where D (mm) is the diameter of the arc tube, d (mm) is the diameter of the central aperture, Vo (mm.sup.3) is the volume of the sodium amalgam sealed in the arc tube when the shortest distance between the sodium amalgam condensed at the corner and the glass solder filled in the central aperture is given by ##EQU2## and WL (W) is the lamp power.

Abstract: A ceramic metal halide high pressure discharge lamp has an arc gap separating the discharge electrodes which is not more than 10 mm and a wall loading which is at least 50 W cm.sup.-2. The relatively small arc gap enables a relatively low operating voltage (in the range from 80V to 130V, say) to be used.

Abstract: A metal vapor discharge lamp has a luminous tube constituted by a translucent ceramic tube member, end caps hermetically fixed to both ends of the translucent ceramic tube member, and electrode supporting tubes hermetically inserted into respective end caps. One of the electrode supporting tubes serves also as an exhaust tube for evacuation and also as a reservoir for a metal charged in the luminous tube. The outer end extremity of this electrode supporting tube is hermetically sealed through fusion by application of heat. This hermetic seal is formed by fusing the end of the electrode supporting tube by application of heat thereto, while keeping a heat-shielding/absorbing plate held in close contact with the electrode supporting tube.

Abstract: A ceramic envelope device for a high-pressure metal-vapor discharge lamp, including a translucent ceramic arc tube, a pair of electrically conducting cermet end caps closing opposite open ends of the ceramic arc tube, and having opposite inner surfaces facing each other, the end caps having a pair of inner holes formed in the opposite inner surfaces of the end caps, respectively, and a pair of discharge electrodes each provided in the form of a rod, having first ends supported in the inner holes in the end caps, respectively, and second ends which protrude from the opposite inner surfaces toward each other in a longitudinally inward direction in the ceramic arc tube.

Abstract: A ceramic envelope device for use in a HID (high intensity discharge) lamp, which includes: (a) a translucent ceramic tube; (b) a pair of electrically conductive end caps which close longitudinally opposite ends of the ceramic tube; (c) a pair of oppositely located discharge electrodes each of which is supported at a first end thereof by a corresponding one of the end caps such that a second end of each electrode protrudes from an inner surface of the corresponding end cap in a longitudinally inward direction in the ceramic tube; (d) an electrical insulator provided for one or both of the pair of end caps; and (e) a sealing member disposed to maintain fluid-tightness between an engaging portion of the end cap for which the electrical insulator is provided, and the corresponding end of the ceramic tube.

Abstract: A ceramic arc tube assembly for an arc discharge lamp includes an arc tube having openings for electrode feedthroughs at opposite ends. The feedthroughs each comprise a niobium tube having a tungsten electrode welded to it. A connection wire is welded to the feedthrough at or near the end of the niobium tube, and the feedthrough is subsequently sealed into the arc tube with the connection wire abutting the arc tube. Since the connection wire is prewelded to the feedthrough, the feedthrough can be made as short as practicable without risk of damaging the seal during welding. As a result, feedthrough material cost is substantially reduced. Preferably, the connection wire is used for locating the feedthrough in the arc tube during seal formation.