Abstract: A dispenser cathode includes a tungsten matrix which is impregnated with an active cathode material and coated with a refractory thin film layer metal material along the surfaces thereto, but not including the electron emissive surface of the matrix, thereby improving a heat transfer efficiency from a heater to the electron emissive surface.

Abstract: A method for manufacturing an impregnated cathode wherein an impregnated pallet is fixedly fitted in a cathode cup. The method comprises the step of disposing electron emitting materials together with a porous pallet in the cathode cup and impregnating the electron emitting materials in the porous pallet to produce the impregnated pallet. The cathode cup is constituted by alloying an oxidative metal or alloy, such as silicon (Si), nickel (Ni) or chromium (Cr), which tends to react oxidatively with the electron emitting materials, in a high heat-resistant metal. In the impregnation process, a bonding of the impregnated pallet to the cathode cup can be achieved by an oxidation reaction between the electron emitting matetrials in the impregnated pallet and the oxidative material in the cathode cup, without any expensive brazing metals or alloys. As a result, it is possible to reduce the manufacturing cost and the total manufacturing processes.

Abstract: A process for manufacturing a dispenser cathode is disclosed, and the process comprises the steps of filling a porous base material into a storage tank, welding the storage tank to a cylindrical sleeve, installing a heater into the sleeve which has, a supporting face to be welded with the storage tank, an outside diameter which is larger than that of the storage tank, and an opening which is smaller than the outside diameter of the storage tank, wherein the heat transfer to the porous base material during the welding is prevented and the thermal efficiency is improved during the operation of the cathode so that a superior cathode characteristic is achieved.

Abstract: An impregnated dispenser cathode comprises a porous metal matrix having electron emissive material is impregnated therein and a cup for storing the porous metal matrix and being fixed together with it. The porous metal matrix is secured to the bottom of the cup. The present invention has the advantage of sharply promoting the value of products as it enhances both their life expectancies and the characteristics of large cathode ray tubes while increasing their reliability by greatly improving the defects of the structure and manufacturing method of conventional impregnated dispenser cathodes.

Abstract: A dispenser cathode comprises an electron emissive materials, a porous base body containing tungsten, a reservoir storing the porous base body, and a sleeve storing the heater therein. The porous base body contains TiO.sub.2 or ZrO.sub.2. The dispenser cathode achieves high luminance and high definiteness required by a large-sized display and the time for manufacturing the cathode is reduced.

Abstract: A dispenser cathode comprises an electron emissive material including at least one selected from the group consisting of Ba and Ba oxide, a porous metal base body having a plurality of diffusing cavities and positioned on the electron emissive material and an alloy thin film layer consisting of scandium tungstate and tungsten which is disposed between the electron emissive material and the porous metal base body. Instead of the alloy thin film, a pellet containing scandium tungstate may be interposed between said electron emissive material and the porous metal base body. The activation aging time of the dispenser cathode of the present invention is greatly shortened as compared with the conventional dispenser cathode, and the damage of Sc by ion bombardment is prevented, and thus the stable thermoelectron emission can be obtained.

Abstract: A dispenser cathode comprises an electron emissive material containing BaAl.sub.4 and Ni, the porous metal base body and a sleeve. The activation aging time of the dispenser cathode according to the present invention is shortened greatly as compared with the conventional dispenser cathode and therefore, the productivity can be increased.

Abstract: A dispenser cathode for an electron gun comprises a reservoir for holding thermoelectron emissive material. A sleeve having an outward flange at a top portion thereof and receives the reservoir at the upper portion thereof and receives a heating element at the other end. A heat shielding tube is provided with an inward flange at the top thereof that overlaps and is welded to the outward flange of the sleeve. A holder for supporting the heat shielding tube is secured thereto.

Abstract: A method for manufacturing a dispenser cathode is disclosed. The method includes a step of immersing, in an aqueous solution containing an aluminum compound, either (1) a powder mixture made by mixing metal powder selected from among Mo, Ta, W or alloys thereof with a carbonate selected form the group of Sr, Ba, Ca, or mixtures thereof or (2) a pellet of such a metal powder mixture formed into a desired shape, such that the aluminum ingredient in the aqueous solution can be impregnated into (1) the powder mixture or (2) the pellet. According to the present method, heat treatment at a temperature of over 1700.degree. C. is not required, unlike conventional methods where such high heat treatment is required. Therefore the decrease of electron releasing efficiency due to adverse reactions generated by the high temperature heat treatment of the prior art can be avoided.

Abstract: An improved scandate cathode is made from a hollow cylinder of a metal that ill not react with Sc.sub.2 (WO.sub.4).sub.3. The first step in making such a cathode is to insert a metal plug at the bottom of the cylinder to a height that will allow the remaining volume of the cylinder to be filled with the reactants WO.sub.3 and Sc.sub.2 O.sub.3. Next, the reactants are heated in a vacuum to about 1100.degree. C. to form the reaction product Sc.sub.2 (WO.sub.4).sub.3. The plug is then removed from the cylinder, the cylinder is inverted, and BaH.sub.2 is added to the volume of the cylinder that had been occupied by the plug. Finally, the cylinder is heated to decompose the BaH.sub.2.

Abstract: The emission properties of oxide cathodes, in which yttrium oxide, scandium oxide or a rare earth oxide is added to the electron-emissive material, are improved by using fine-grained yttrium, scandium or rare earth oxide.

Abstract: A cathode for an electron gun and its manufacturing method are disclosed. The cathode comprises thermoelectron emission substance layer composed of triple composite oxide of alkaline earth metal formed by thermally decomposing triple carbonate of alkaline earth metal such as barium, strontium and calcium, containing a fourth substance. The fourth substance consists of scandium nitrate or indium nitrate so that the fourth substance can be uniformly dispersed into the thermoelectron emission substance layer, and thus the thermoelectron emission characteristics and durability of the cathode can be remarkably enhanced.

Abstract: A dispenser cathode is designed with an emitting surface including at least one emitting groove characterized by steep opposing walls oriented parallel to the ion flow wherein the walls have a given depth and are separated from each other by a given distance such that bombarding ions which impinge on one wall cause emitting material depleted therefrom to be deposited on the opposite wall. The cathode design, particularly the groove area, width and depth, are selected to optimize its emission current density, operational characteristics, and lifetime. Since the grooved dispenser cathode eliminates the effects of ion bombardment without sacrificing performance, the improved dispenser cathode can be used in thyratons and other gas filled electron tubes to provide an order of magnitude improvement in performance over standard cathodes.

Abstract: A low work function surface for a dispenser cathode structure. The cathode structure comprising a heater and an electron emitting surface substrate or core composed of a porous tungsten matrix impregnated with a barium containing impregnant distributed therethrough. The structure is made by a method in which a nanometer thick layer of scandium oxide is sputtered onto the outermost surface of the impregnated tungsten core, or substrate, and then oxidized by exposing the sputtered scandium oxide surface layer to an oxygen atmosphere. The oxidized surface layer is activated by turning on the heater, for example, to cause the release of a small portion of the barium in the barium-containing impregnant. Some of the released barium migrates into the scandium oxide surface layer to form a monolayer of barium oxide on at least a portion thereof.

Abstract: A dispenser cathode for a gas filled tube is fabricated from a porous metal material impregnated with an electron emitting material and has on an emitting surface at least one geometric aperture of a given depth and width and having steep vertical walls which serve to compensate for the deleterious effects of ion back bombardment.

Abstract: The lifetime of oxide cathodes comprising, for example BaO and SrO as an emissive material, is improved by adding hafnium oxide or zirconium oxide.

Abstract: A low work function surface for a dispenser cathode structure. The cathode structure comprising a heater and an electron emitting surface substrate or core composed of a porous tungsten matrix impregnated with a barium containing impregnant distributed therethrough. The structure is made by a method in which a nanometer thick layer of scandium oxide is sputtered onto the outermost surface of the impregnated tungsten core, or substrate, and then oxidized by exposing the sputtered scandium oxide surface layer to an oxygen atmosphere. The oxidized surface layer is activated by turning on the heater, for example, to cause the release of a small portion of the barium in the barium-containing impregnant. Some of the released barium migrates into the scandium oxide surface layer to form a monolayer of barium oxide on at least a portion thereof.

Abstract: An indirectly heated type cathode assembly comprises a cathode sleeve having a heater within itself and having an emitter-impregnated type cathode disc fitted at one end, a plurality of straps connected at one end to a lower end portion of the cathode sleeve, and a cylinder holder whose upper end is connected to the other end of each strap, the holder being located outside the cathode sleeve such that it is spaced a predetermined distance apart from the cathode sleeve. A heat reflecting cylinder is located between the cathode sleeve and the holder of the indirectly heated type cathode assembly such that it is coaxial with the cathode sleeve and holder. The heat reflecting cylinder is supported by the holder and each strap extends such that it is not in contact with the heat reflecting cylinder. The strap is made of a Ta-W alloy or a Ta-W-Hf alloy.

Abstract: A long life high current density cathode is made from a mixture of aluminum xide and tungsten oxide powders by processing the powders into a fused powder, adding barium hydride to the fused powder, inverting the fused powder and heating to decompose the barium hydride and obtain barium metal.

Abstract: A cathode is made from a mixture of tungsten and iridium powders using a ction product formed from reacting a Group III A metal powder with barium peroxide powder as an impregnant.

Abstract: A cavity reservoir type dispenser cathode includes a first pellet, a second pellet, a cup and a sleeve, the first pellet being made by sintering a mixture of at least one metal selected from among W, Mo, Ta and alloys thereof, at least one metal selected from among Os, Ir, Ru, Re and alloys thereof, and Sc.sub.2 O.sub.3, the second pellet being made of a mixture of barium-calcium aluminate and In.sub.2 O.sub.3, the first and second pellets being inserted into a cup and the cup being inserted into and welded to a sleeve. The cavity reservoir type dispenser cathode of the present invention has a high saturation current density at lowered temperatures to prevent deformations and shortening of life expectancy of nearby components due to a high operating temperature.

Abstract: A novel technique for mounting a disc of lanthanum hexaboride electron emission material within a hot cathode assembly of an electron gun is described. The disc is partly received in a recess of a graphite mounting member and the combined disc and mounting member are pushed to the end of a 50/50 molybdenum rhenium tube which has a rolled over lip which engages the disc. Indentations are formed in the tube and these extend into the mounting member to secure the mounting member to the tube. All contacting surfaces between the disc and mounting member and between the disc and lip are previously coated with colloidal graphite to improve electrical and thermal conductivity. Prior to securing the disc and mounting member to the tube the tube is secured to an alumina support ring by cutting and forming retaining lips from the tube and by flaring an end of the tube.

Abstract: According to the present invention, an impregnated cathode is provided wherein an alloy layer of iridium and tungsten is formed on a surface of a porous pellet impregnated with an oxide of an alkali earth metal, wherein a crystal structure of the alloy has an .epsilon.II phase comprising an hcp structure whose lattice constants a and c satisfy 2.76.ltoreq.a.ltoreq.2.78 and 4.44.ltoreq.c.ltoreq.4.46, respectively. The impregnated cathode of the present invention maintains stable electron emission characteristics from an early stage of operation.

Abstract: A method of producing a dispenser cathode provided with a top layer, in which a main body of tungsten powder is pressed to a moulding at a first pressing pressure which is sufficient to preserve the shape of the moulding when the first pressure is removed but is not sufficient to break the powder grains to a significant extent. This moulding is thereafter provided with a top layer of a second power, whereafter the overall assembly is compressed in a second pressing operation at a second, higher pressing pressure, at which pressure the powder grains are broken to a significant extent.

Abstract: A long life high current density cathode is made from a mixture of tungsten nd iridium powders by processing the mixture of powders with an activator into a porous billet, and then impregnating the billet with a low melting point impregnant by firing the billet in a dry hydrogen furnace at a temperature at which the impregnant melts.

Abstract: A dispenser cathode and method for making the same are disclosed wherein a mixture of tungsten and aluminate powders are pressed by a die into a foil sleeve. A heater assembly can be attached to the back of the pellet for activating the emissive material. An impregnated cathode therefore can be manufactured in a few hours by relatively inexpensive processing techniques.

Abstract: An impregnated cathode which has a portion where no electron emissive material is present on the surface layer of the cathode base body that is to be welded, in order that the cathode base body impregnated with the electron emissive material, a cup and a cathode sleeve can be firmly welded together. The cathode base body which has no electron emissive material on the surface layer is obtained by washing the cathode base body in a solvent which is capable of dissolving the electron emissive material. Using this cathode base body, the impregnated cathode is fabricated.

Abstract: A four-piece, easily manufactured dispenser cathode capable of current densities up to and exceeding 10 Amperes per square centimeter is particularly adapted for CRT applications because of its surprisingly low cost. A refractory material reservoir contains a pellet of tungsten and barium calcium aluminate and is sealed by a pellet of porous tungsten or tungsten mixture. The reservoir/pellet assembly is contained in a support cylinder to which the porous tungsten pellet may be welded. The inventive process includes the steps to prepare the pellets and assemble the four elements of the cathode.

Abstract: A dispenser cathode such as a metal capillary cathode for electrical discharge devices which has a hollow cylindrical head portion 1 which carries a porous emission wafer 3 of a refractive material at its upper end and covers a cathode cartridge 2 which contains an active material supply 4 and comprises an epoxy helical heater 5 surrounded by a metal sleeve 6. Two part division of the structure allows separate testing possibility of the emission wafer and the heater/supply cartridge and also allows an improvement in the heat transmission from the heater to the emission wafer. For this purpose, a hollow cylindrical head portion 1 is conically-shaped and expands outwardly toward the cathode cartridge 2 and the upper part of the cathode cartridge 2 is conically tapered so as to mate with the hollow cylindrical head portion and the two portions are connected together wherein their conical side walls are attached by welding in the upper portion of the drawn up metal sleeve.

Abstract: To improve the homogeneity of the porosity of a concave-convex pressed part with minimized mass, a pre-compressed pressed part with plane frontal surfaces is produced in a first process step. This part is then further compressed to produce a concave-convex sintered pressed part in a further process step. The pressed part can, however, also be produced in only one process step, if the requirements for homogeneous porosity distribution are less.

Abstract: A reactionless thermionic cathode for electronic tubes consists of a metallic or ceramic support and an alloy, preferably an intermetallic compound, containing the actual emission-promoting element, with a metal from the group comprising those of the VIIIth vertical row of the periodic table and rhenium. The preferred activation substances are platinides of the elements having a low electron work function, predominantly Ba and La. The cathode is manufactured by wet-mechanical, cataphoretic or electroplating application of the activation substance to the support or by infiltration of the porous support having a pore volume of at least 10%. High emission current densities are obtained at relatively low operating temperatures.

Abstract: A controlled porosity dispenser cathode and method of manufacture therefo using chemical vapor deposition and laser drilling, ion milling, or electron discharge machining for consistent and economical manufacturing a cathode with pores on the order of 0.2 to 2 .mu.m in diameter.

Abstract: A long life high current density cathode is made from a mixture of tungsten nd iridium powders using a barium iridiate as the impregnant by processing the mixture of powders with an activator into a porous billet, and then impregnating the billet with a barium iridiate by firing the billet in a dry hydrogen furnace at a temperature at which the impregnant melts.

Abstract: The face of a cathode surface is machined to provide a spiral surface fin with microscopic sharp symmetrical protrusions. The cathode gives enhanced emission due to field emission generated at the sharp symmetrical protrusions and due to the increased surface area.

Abstract: A camera tube device for use in a television camera comprises an electron gun including a cathode electrode for emission of an electron beam, and first and second grid electrodes respectively having apertures for controlling the diameter of the electron beam. The aperture of the second grid electrode is sufficiently smaller than the aperture of the first grid electrode. The first grid electrode is applied with a positive voltage relative to the cathode electrode and the second grid electrode is applied with a positive voltage relative to the cathode electrode which is higher than that applied to the first grid electrode. The positive voltage applied to the first grid electrode has such a value that forms the electron beam having passed through the aperture of the first grid electrode into a laminar flow beam.

Abstract: Porous agglomerates are made from pure tungsten by sintering fine particles together and mechanically breaking down the mass to form some agglomerates considerably larger than the particles. These agglomerates are mixed with fine iridium powder and sintered to form a porous mass. The mass is machined to the cathode shapes and impregnated with an alkaline earth aluminate. The large agglomerates alloy with the iridium only on their outer surface. Their pure tungsten interior provides the surfaces to reduce the alkaline earth oxide to the metal which activates the cathode.

Abstract: The invention relates to a method of manufacturing a dispenser cathode having a porous tungsten body, in which a metal oxide is provided in the body and the body is impregnated with barium. Good results as regards life and resistance to ion bombardment are obtained if the comparatively cheap oxides of gallium and indium are used.

Abstract: The invention provides a travelling wave tube having a directly heated cathode. Cathode material is applied in a depression in one U-shaped member of a high resistance alloy material and the return path for heater current is provided by another U-shaped strip member beneath the first. The configurations of the two strip members are similar so that stray magnetic fields generated by the equal but opposite currents flowing therein, tend to neutralize one another. In another embodiment the two strip members are replaced by generally cylindrical members, one member being within the other. The surface of the member providing the return path for heater current is polished where it faces the member carrying the cathode material so as to reflect back heat radiated by the last-mentioned member.

Abstract: A beam generating system for electron tubes, particularly travelling wave tubes, is formed of a beam shaping electrode and a dispenser cathode supported therein having an emission disk at its end face. A positional change of the dispenser cathode in the beam shaping electrode at different ambient temperatures is suppressed with the beam generating system, and thus a beam defocussing is avoided. According to the invention, the dispenser cathode is directly connected to the beam shaping electron and is connected below the emission disk by means of a radial cathode support. The beam generating system of this type is particularly employed in travelling wave tubes.

Abstract: In a directly heated cathode including a base formed of an alloy containing nickel as its principal component and coated with an oxide of an alkaline earth metal which emits electrons, a layer of a metal selected from the group consisting of nickel, cobalt, platinum and rhodium or of an alloy containing one of these metals as its principal component is formed on both surfaces of the base to one of which surfaces the coating of the oxide is applied, so as to thereby prevent the peeling-off of the coating of the oxide from the base. In order to avoid deformation of the base, a powder alloy containing tungsten and nickel as its principal components, a powder alloy containing molybdenum and nickel as its principal components or one of these powder alloys which is coated with nickel, cobalt or a cobalt-nickel alloy is deposited on the surface of the base to which the coating of the oxide is applied.

Abstract: A dispenser cathode body is manufactured from a sintered metallic powder. A large scandium oxide concentration is provided beneath an emissive surface of the body, resulting in increased life, increased current density, and decreased sensitivity to ion bombardment.

Abstract: An emitter-dispenser housing for a controlled porosity dispenser cathode manufactured of a single material as a unitary piece by a chemical vapor deposition process in which a configured mandrel is coated with a layer of material such as tungsten, for example, so that when the mandrel is removed from the coating of material a hollow housing is formed having a side wall and an end wall which define a reservoir. In addition, intersecting strips of this same material as the coating, which had been placed in the mandrel, extend transversely across the reservoir with the edges thereof atomically bonded to the coating during the chemical vapor deposition to form a unitary piece. Thereafter an array of apertures is formed in the end wall of the housing by laser drilling to create an emitter-dispenser.

Abstract: A thermionic cathode (FIG. 1) comprises an emitter (3) comprising a matrix (4) of tungsten impregnated with an alkaline earth activator. The matrix is coated with a coating (5) of about 20-30% osmium fully alloyed with tungsten formed by cosputtering osmium and tungsten onto the matrix. A diffusion barrier (6) of osmium may be interposed between the matrix 4 and coating (5) (FIG. 2) and, optionally, osmium may be diffused into the matrix (4). Alternatively the whole matrix may comprise a mixture of about 20-30% osmium fully alloyed with tungsten (FIG. 3). Alternative to osmium and tungsten may be used, and various modifications may be made, and other methods of making the emitter may be used. In particular the proportion of osmium may be about 40%.

Abstract: Directly heated oxide cathode especially for velocity-modulated tubes in pulse operation, characterized by the features that an outer conductor is designed cylindrically and an inner conductor is coaxially arranged by means of a ceramic support disc, and that on one end face, a metal layer connected to the outer conductor and the inner conductor is provided with an electron-emitting oxide layer.

Abstract: By providing the cathode, in a diode electron gun in a television camera tube, with an at least 40 .mu.m high collar extending in the direction of the anode, the anode current is considerably reduced.

Abstract: The cathode (4) the material of which is substantially high-melting metal such as W, Mo, Ta, Nb, Re and/or C, consists of a very fine-grained mechanically stable support layer (5), a series of layers (6) considerably enriched with emissive material, in general from the scandium group especially from the group of rare earth metals, preferably with Th or compounds thereof and a thermally stable preferentially oriented coating layer (7). All the layers are provided via the gaseous phase, for example, CVD methods, on a substrate (1) formed according to the desired cathode geometry. The substrate (1) is removed after termination of the deposition. FIG. 2.

Abstract: An impregnated cathode comprises a porous refractory substrate of refractory material such as tungsten containing at least one of scandium oxide particles and oxide particles containing scandium such as (Al, Sc).sub.2 O.sub.3, and an electron emissive material impregnated into pores of the substrate, and has an operating temperature lower by about 300.degree. C. than that of the conventional impregnated cathode containing no scandium oxide particles, or scandium.

Abstract: This invention concerns a thermoelectronic cathode for hyperfrequency electron tubes.The cathode comprises a cylindrical molybdenum casing, the lower portion of which contains a heating filament, while the upper portion contains two superimposed porous bodies, the lower one made from impregnated material, and the upper one from non-impregnated material.

Abstract: A thermionic cathode (FIG. 1) comprises a porous matrix of tungsten (4) impregnated with alkaline earth activator.A coating (5) 1 .mu.m thick is formed on the matrix (4). The coating is of .sigma. phase alloy of molybdenum and osmium.Alternative .sigma. phase alloys are disclosed, and various methods of making cathodes are disclosed.

Abstract: A hollow cathode discharge device is disclosed for ion plating a substrate with high temperature metal vapor. A hollow cathode tube is adapted to receive pellets of the high temperature metal at a short location from the cathode tube opening which is selected to correspond to a temperature peak along the length of the cathode tube. The temperature peak is a characteristic of the cathode diameter and gas flow rate in the tube. Inert gas is supplied to the tube and, the tube may be shielded and provided with a constriction at its end opening. An anode is spaced from the cathode tube opening and power supply is provided for supplying a negative bias to the cathode tube and a positive bias to the anode.