Abstract: Sealing means for arc discharge tubes employ chamfers formed in the arc tube which mate with frusto-conical portions on sealing disks. Self-centering is thus provided as well as the elimination of one wire stop positioner for holding the sealing disks.

Abstract: A ceramic envelope device for a high-pressure metal-vapor discharge lamp, including a translucent ceramic tube, a pair of electrically conducting end caps closing opposite open ends of the ceramic tube, a pair of oppositely located discharge electrodes each of which is supported at one end thereof by an inner hole in the corresponding end cap, and a pair of power-supply lead members each of which is supported at one end thereof by an outer hole in the corresponding end cap. A space or radial gap is formed between at least a portion of an outer surface of the electrodes and lead members and their respective supporting holes. At least one of the electrodes and the lead members is formed from a twisted wire consisting of a plurality of metallic strands. The electric resistance of each end cap may fall within a range of 0.1-5 .OMEGA..

Abstract: A ceramic envelope device for a high-pressure metal-vapor discharge lamp, including a translucent ceramic tube, a pair of electrically conducting end caps closing opposite ends of the ceramic tube, and a pair of opposed discharge electrodes each of which is supported at its one end by the corresponding end cap such that the other end of the electrode protrudes from the inner surface of the corresponding end cap in a longitudinally inward direction of the ceramic tube. Each of the end caps is covered at its inner surface with an electrical insulator. The electrical insulator has a protruding portion surrounding a part of the corresponding electrode which protrudes from a radially central portion of the inner surface of the corresponding end cap. The surrounded part of the corresponding electrode is radially spaced from the protruding portion (the electrical insulator).

Abstract: A seal button comprising a first circular portion having a diameter approximately equal to the outside diameter of the arc tube, the first circular portion having a groove extending across the diameter of the first circular portion, the groove having a depth greater than or approximately equal to the thickness of the first circular portion; and a second circular portion concentric with and extending from the first circular portion, the second circular portion having a diameter of appropriate length for being inserted into an end of the arc tube; the seal button having an opening extending axially through the approximate center thereof, the opening being configured for receiving the electrical feedthrough portion of an electrode assembly.

Abstract: An arc discharge lamp is provided using sealing compositions comprising mainly Al.sub.2 O.sub.3 --SiO.sub.2 --MgO. Preferred compositions include between 25 to 28% by weight of MgO and 13 to 21% by weight of Al.sub.2 O.sub.3 since these have lower melting points than others in the group. The sealing compositions are used to seal end closure members of alumina or cermet to ceramic arc tubes for use in discharge lamps. The compositions are selected to have linear expansion co-efficients compatible with the materials of the end closures and arc tubes. The methods described give sealing times of between 3 and 4 minutes.

Abstract: A ceramic envelope device for a high-pressure metal-vapor discharge lamp, including a translucent ceramic tube, a pair of end caps closing opposite ends of the ceramic tube, and a pair of oppositely located discharge electrodes each of which is supported at a first end by the corresponding end cap such that a second end of the electrode protrudes from an inner surface of the corresponding end cap in the longitudinal direction of the ceramic tube. The end caps are electrically conductive, and completely covered at their inner surfaces with an electrical insulator.

Abstract: An arc discharge lamp is provided using sealing compositions comprising mainly Al.sub.2 O.sub.3 --SiO.sub.2 --MgO. Preferred compositions include between 25 to 28% by weight of MgO and 13 to 21% by weight of Al.sub.2 O.sub.3 since these have lower melting points than others in the group. Additives of B.sub.2 O.sub.3, nucleating agents and HfO.sub.2 and other rare earth oxides are preferred. The sealing compositions are used to seal end closure members of alumina or CERMET to ceramic arc tubes for use in discharge lamps. The compositions are selected to have linear expansion co-efficients compatible with the materials of the end closures and arc tubes. The methods described give scaling times of between 3 and 4 minutes.

Abstract: In a high pressure sodium discharge lamp it has been found that rectification can be prevented by ensuring the amalgam does not make electrical contact with the electrode. To achieve this according to the invention a small shoulder member is provided on the inside face of the end wall. Although the small height effectively reduces the temperature differential between the bottom of the shoulder and the top the necessary differential to prevent the amalgam condensing out the top of the shoulder member is maintained by ensuring the width of the shoulder member is a predetermined minimum thickness.

Abstract: High pressure discharge lamps have discharge tubes of ceramic material having end caps into which electrodes are mounted on fixed shanks. The invention provides a preferred construction for mounting on electrode shank or an external conducting member in a cermet end cap. A metal coil is fixed in a respective opening in the end cap and supports the respective shank or conductor therein. Preferably the cermet is pressed into the desired shape with an aperture in it. The coil is inserted into the aperture so that after sintering the coil is fixed into the sintered cermet.

Abstract: A rapid start fluorescent lamp having an external conductive strip has a resistive element in the lamp base electrically connected to the conductive strip and a pin of the lamp base. The resistive element is made from a material which has a volume resistivity of about 10.sup.5 to about 10.sup.8 ohm-cm and a deflection temperature greater than 250.degree. C. at 1,820 kilo dynes/cm.sup.2. The resistive element is mounted in the lamp base metal housing and supports the metal pins or the resistive element is made into a washer shaped element and attached to one of the pins on the inside of the lamp base.

Abstract: An improved end closure for a tubular light-transmitting ceramic envelope used in sodium vapor lamps is disclosed which comprises assembly of a ceramic disc fitted into one end of a metal sleeve having a different diameter opening at its opposite end for circumferential engagement with the arc tube inserted therein with all of the assembled members being hermetically sealed together by a ceramic sealing frit. The improved end closure permits thermionic electrodes to be inserted through openings in the ceramic discs with said electrodes being hermetically sealed at said openings with additional ceramic sealing frit.