Abstract: An infra-red lamp consists of a quartz tubular envelope sealed at each end with a respective pinch seal. A tungsten filament supported within the envelope is electrically connected, via a molybdenum foil strip and lead wires within the pinch seal to a connector for connection to a power supply. Each pinch seal is substantially wholly enclosed within a ceramic housing, which is preferably provided with a locating flange, to protect the pinch seal in part from heat emitted by the filament and to assist in location of the lamp in an operating environment.

Abstract: An electrically conducting cermet for use in a closure assembly in a high pressure sodium discharge lamp which cermet comprises a sintered compact of refractory oxide granules and a conducting network extending throughout the cermet wherein said network is provided by a layer of niobium and, optionally, at least one other specified metal. The cermet is, because of the niobium content of the metallic network, permeable to hydrogen and lamps incorporating this cermet can therefore be stabilized in acceptable times.

Abstract: The invention provides an advantageous shape of discharge tube and a discharge lamp including such a tube which is particularly beneficial for use in dimensions intended to replace general lighting service lamps but can readily be adapted to other sizes. The discharge tube is shaped to define a substantial part of the boundary of a substantially planar zone. The part of the tube defining the boundary includes at least one straight portion. In one embodiment it defines three sides of a square with the ends of the tube being re-entrant into the fourth side. In a preferred embodiment a support housing central to the zone holds the ends of the tube thereby supporting it. Preferably one or more arms extending from the support housing grip the tube between its ends for further support. The support housing may include some circuit elements and provides electrical connection to the lamp as well as providing a convenient point to handle the lamp.

Abstract: The invention relates to a single ended discharge lamp, such as a CID or CSI lamp having a bi-pin base. The base is such as to fit a socket suitable for lamps such as tungsten halogen filament lamps for which lower voltages are used and is adapted to make use in such sockets possible. The base or cap member is provided in the usual manner with two pins but at least one of the pins is a dummy pin. At least one extra terminal is disposed to the side of the base whereby electrical connection to one electrode of the lamp is by a flying lead. The other terminal may be the other pin or may be disposed at the other side of the base. In that event both pins may be electrically disconnected from the electrodes and serve only for support or positioning of the lamp.

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: The invention provides a tungsten halogen linear incandescent lamp having a gas fill comprising a mixture of CHI.sub.3 and (PNBr.sub.2).sub.3. Gas fills according to the invention comprise from 6 to 32 micrograms of (PNBr.sub.2).sub.3 per c.c. of the lamp internal volume with a ratio of CHI.sub.3 to (PNBr.sub.2).sub.3 of from 1:1 to 5:1 and result in lamps having a increased efficacy and a life of more than 2,000 hours.

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: The invention provides an advantageous shape of discharge tube and a discharge lamp including such a tube which is particularly beneficial for use in dimensions intended to replace general lighting service lamps but can readily be adapted to other sizes. The discharge tube is shaped to define a substantial part of the boundary of a substantially planar zone. The part of the tube defining the boundary includes at least one straight portion. In one embodiment it defines three sides of a square with the ends of the tube being re-entrant into the fourth side. In a preferred embodiment a support housing central to the zone holds the ends of the tube thereby supporting it. Preferably one or more arms extending from the support housing grip the tube between its ends for further support. The support housing may include some circuit elements and provides electrical connection to the lamp as well as providing a convenient point to handle the lamp.

Abstract: The invention provides a lantern for an area light, particularly one having a cut-off light distribution. A central area of a transparent or transluscent bowl of the lantern has in alternation externally facing reflecting prisms and flats. There are sufficient flats to transmit at least one third of the vertical light and sufficient proportion of prisms to provide a completely flashed prism bank at the direction of peak intensity which is preferably 60.degree.-65.degree. from the vertical. The prism bank controls the vertical light, so that the intensity in a vertical 60.degree. cone does not exceed 80% of peak intensity, more efficiently than internal prisms. The flats have the additional advantage of facilitating ease of cleaning.

Abstract: In a fluorescent lamp electrode assembly a coil electrode is supported on lead wires sealed in a glass flare. It has been found that during on-off switching cycles distortion occurs in the lead wires. To solve this it is proposed to make the lead wires, at least in the region of the electrodes, of single phase material, specifically austenitic steel. If difficulties are presented of matching coefficients of expansion of lead wires and flare the inner parts of the lead wires only may be of that material using a multi part welded structure in which the other parts are of, say, nickel-iron alloy or dumet.