Abstract: A linear filament assembly for a halogen cycle or other incandescent lamp comprises a generally linear filament usually a coil or coiled coil, supported at opposite ends by substantially rigid conductive leads. A rigid insulating rod, preferably of quartz extends generally parallel to the filament, and a plurality of supports extend between the rod and the filament, each support being fixedly secured to the rod and supporting the filament. The supports are embedded in the rod, this being achieved by heating the rod at the point of insertion until it is sufficiently soft to insert the wire without excessively distorting the rod.

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: A phosphor for use in fluorescent lamps which comprises calcium sulphate and, optionally, up to 50% of strontium sulphate together with cerium (0.5-10%), manganese (up to 10%), an alkali metal (0.001 to 3%) and boron and/or aluminium (0.001 to 8%). The phosphor may be produced by blending and then firing the individual components. Tubes for use in the lamps may be electrostatically coated with the phosphor.

Abstract: Synthetic willemite phosphor for use in fluorescent lamps in the form of particles coated with from 0.001% to 0.5% of an oxide of scandium, yttrium, lanthanum or a rare earth element. Fluorescent lamps comprising the phosphor which have improved aging qualities are also provided.

Abstract: A linear filament assembly for a halogen cycle incandescent lamp comprises a generally linear filament (usually a coil or coiled coil) supported at opposite ends by substantially rigid conductive leads, a rigid insulating rod, for example of quartz, extending generally parallel to the filament, and a plurality of supports extending between the rod and the filament, each support being fixedly secured to the rod, for example by having a coil part fitting over the rod and also being formed with a coil loosely exbracing the filament. The coils embracing the filament preferably include several closely spaced turns which loosely embrace part of the filament coil, without screwing into or engaging individual pitches of the latter.

Abstract: A lighting unit for a glide path lighting system comprises a light source, a lens, and a colored interference filter part way across the light path between the light source and the lens, arranged so as to produce a light beam having a white part, a colored part and a transition region. The filter is inclined at an angle of approximately 6.degree. to a plane normal to the optical axis of the unit.

Abstract: An electrically conducting cermet comprises a sintered compact of refractory oxide granules such as alumina granules having diameters of from 50 to 800 microns and a conductive network extending through the cermet and provided by a layer of one or more of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, iron, cobalt or nickel surrounding the individual oxide granules and constituting a volume fraction of 0.04 to 0.2 of the total cermet, wherein particles of one or more of said metals are dispersed within the oxide granules in a volume fraction of 0.01 to 0.15 of the granules, which granules also contain 0.01 to 0.25 percent by weight of magnesium oxide.

Abstract: Sealing materials for making heat-resistant seals in electrical discharge devices comprise a rare earth oxide, such as lanthanum oxide, and boric oxide, preferably together with minor amounts of phosphorus pentoxide, aluminium oxide and magnesium oxide. Preferred compositions comprise 55 to 95% lanthanum or other oxide, 5 to 45% boric oxide and 0 to 5% phosphorus pentoxide, 0 to 5% aluminium oxide and 0 to 5% magnesium oxide. The compositions can be made by mixing the oxides, or appropriate salts, calcining the mixture at up to 1200.degree. C. and crushing it to a powder. They may be used as frits in a slurry or formed into pressed elements such as discs or washers. Sealing can be accomplished by heating the surfaces to be joined, together with the interposed sealing composition, to a temperature between 1100.degree. and 1650.degree. C.

Abstract: An electron beam tube assembly has a pattern of conductors 20 at least partially provided by being deposited on a major surface of a face plate 16, of the tube 13, the conductors to extend from within the tube 13, at least to an edge 18 of the face plate spaced from the remainder of the tube, and at the edge providing a plurality of exposed, spaced apart ends 22, comprising electrodes, the opposite end of each conductor being coupled by resistive material 28 deposited on the tube to a conductive coating 26 also on the tube, the coating being maintained at a high positive potential with respect to the cathode, in response to the information signals, supplied to the electron beam deflection means 41 and/or to the electron beam modulation means 42, electrical discharges occur to mark an associated sheet 30 of material sensitive to electrical discharges each such electrical discharge being when the electron beam impinges on a conductor.

Abstract: An improved filament support of especial value in linear tungsten halogen lamp of low wattage, is formed from a composite wire which comprises a core wire overwound with a further wire, both of tungsten. The supports according to the invention afford better grip and reduced weight as compared with the supports of the prior art.

Abstract: A cathode ray tube assembly has a circuit arrangement to connect the heater R1 of a cathode ray tube to an associated D.C. supply, (via terminals 12 and 13), and the circuit arrangement also includes at least one component, such as two components comprising astigmatism correction coils 10, to be energized by the D.C. supply, and a matrix of assymetrical conducting devices, for example, a diode bridge D1, D2, D3 and D4, arranged to ensure that the current flow through each of said at least one component individually is in one predetermined direction, irrespective of the direction of the flow of current from the D.C. supply.

Abstract: Metal halide discharge lamps based on sodium and scandium iodides show improved color rendering without important loss of efficacy by the inclusion of lithium iodide, especially in the molar proportion of 10-50% LiI based on the total of Li, Na and Sc iodides. The ratio of alkali metal of SC iodides should be between 5.4:1 and 57.5:1. Especially preferred are lamps with less than 10 molar % ScI and the lamps may additionally contain caesium iodide to broaden the emission spectrum.

Abstract: The inclusion of an alkali metal halide in the gas fill of a high pressure mercury and aluminium halide discharge lamp improves the color appearance of the lamp; notably by lowering the color temperature, while maintaining or even increasing the efficacy and stability of the discharge. Preferred contents are 10 to 30 mg cm.sup.-3 mercury, 5 to 100 .mu.mol cm.sup.-3 aluminium halide and 0.5 to 150 .mu.mol cm.sup.3 alkali metal halide, with the molar ratio of alkali metal halide to aluminium halide in the range 0.1 to 1.5 and the total number of aluminium and alkali metal atoms preferably greater than the total number of halogen atoms.