Abstract: The invention relates to an electrode having a nano-hollow array on the surface thereof, the nano-hollow array comprising a plurality of nano-pores or nano-balls, each pore having a diameter of less than 500 nm, formed by a process comprising depositing a uniform metal film on the electrode structure surface at a rate of 2 ? per second or less, annealing the metal film under rapid anneal conditions at a temperature within about 100 degrees of the melting point of the metal film and without subjecting the metal film to a temperature ramp-up to create metal droplets, and anodizing and over-anodizing the metal droplets in the presence of an anodization agent for the metal at from 20 to 200 volts at 0.1 to 2 amps to create nano-pores in the metal droplets or nano-balls to, creating increased surface area and increased electric field around the electrode which enhances speed of fill gas ionization.

Abstract: In accordance with one embodiment, the hollow cathode is comprised of a first tantalum tube, tantalum foil, and a second tantalum tube. The foil is in the form of a spiral winding around the outside of the first tube and is held in place by the second tube, which surrounds the foil. One end of the second tube is approximately flush with one end of the first tube. The other end of the second tube extends to a cathode support through which the working gas flows. To start the cathode, a flow of ionizable inert gas, usually argon, is initiated through the hollow cathode and out the open end of the first tube. An electrical discharge is then started between an external electrode and the first tube. When the first tube is heated to operating temperature, electrons are emitted from the open end of the first tube.

Abstract: In accordance with one embodiment, the hollow cathode is comprised of a first tantalum tube, tantalum foil, and a second tantalum tube. The foil is in the form of a spiral winding around the outside of the first tube and is held in place by the second tube, which surrounds the foil. One end of the second tube is approximately flush with one end of the first tube. The other end of the second tube extends to a cathode support through which the working gas flows. To start the cathode, a flow of ionizable inert gas, usually argon, is initiated through the hollow cathode and out the open end of the first tube. An electrical discharge is then started between an external electrode and the first tube. When the first tube is heated to operating temperature, electrons are emitted from the open end of the first tube.

Abstract: A hollow cathode having at least a portion of the inner, outer or both surfaces coated with a layer of a getter material is described. Some methods for the production of the hollow cathode of the invention are also described, which include cathodic and electrophoretic deposition of the getter layer onto the hollow cathode.

Abstract: Hollow cathode microdischarges in a tube geometry provides the formation of stable, high-pressure discharges in a variety of flowing gases including argon, helium, nitrogen, and hydrogen. Direct current discharges are ignited in stainless steel capillary tubes (dhole=178 &mgr;m) which are operated as the cathode and using a metal grid or plate as the anode. Argon discharges can be sustained at atmospheric pressure with voltages as low as 260 V for cathode-anode gaps of 0.5 mm. In one embodiment using a molybdenum substrate as the anode, microjets are struck in H2/CH4 mixtures at 200 Torr to deposit diamond films with well-faceted crystals. Optical emission spectroscopy of discharges used for growth confirms the presence of atomic hydrogen and CH radicals. Ballasting of individual tubes allows parallel operation of the microjets for larger area materials processing.

Abstract: In accordance with one embodiment of the present invention, the hollow-cathode apparatus comprises a small-diameter tantalum tube with a plurality of tantalum-foil radiation shields, wherein the plurality of shields in turn comprise one or more spiral windings external to that tube and approximately flush with the open end from which electron emission takes place. The axial length of at least one of the inner windings (closer to the tantalum tube) is equal to or less than approximately half the length of the tantalum tube. An enclosed keeper surrounds the cathode. To start the cathode, a flow of ionizable inert gas, usually argon, is initiated through the cathode and out the open end. An electrical discharge is then started between the keeper and the hollow cathode. When heated to operating temperature, electrons exit from the open end of the hollow cathode.

Abstract: Cold electrodes for gas discharges have an electrically conductive carrier material on which an emission coating is disposed. The photoelectric output work of the material of the emission coating is less than that of the carrier material or less than 5.6*10-19 joule/electron. The emission coating can, in particular, contain yttrium. The electrode preferably has the form of a hollow body and can be embedded in a glass body.

Abstract: A field emission display having an improved operational life. In one embodiment of the present invention, the field emission display comprises a plurality of row lines, a plurality of column lines, and a plurality of electron emissive elements disposed at intersections of the plurality of row lines and column lines, a column driver circuit, and a row driver circuit. The column driver circuit is coupled to drive column voltage signals over the plurality of column lines; and, the row driver circuit is coupled to activate and deactivate the plurality of row lines with row voltage signals. Significantly, according to the present invention, operational life of the field emission display is substantially extended when the electron emissive elements are intermittently reverse-biased by the column voltage signals and the row voltage signals. In another embodiment, the row driver circuit is responsive to a SLEEP signal.

Abstract: An impregnated cathode and a method of manufacturing the same are provided for suppressing emission of unwanted electrons and particles generated from an excess electron emitting substance so as to achieve a steady electron emission characteristic. The impregnated cathode is placed directly beneath an electron emission hole of a first grid. The impregnated cathode is made up of a first sintered porous element whose surface functions as an electron emitting region and a second sintered porous element whose surface is a peripheral region other than the electron emitting region. The porosity of the first sintered porous element is greater than that of the second sintered porous element. Not only the first sintered porous element having the electron emitting region but also the second sintered porous element corresponding to the region around the electron emitting region is impregnated with the electron emitting substance.

Abstract: A field emission display having an improved operational life. In one embodiment of the present invention, the field emission display comprises a plurality of row lines, a plurality of column lines, and a plurality of electron emissive elements disposed at intersections of the plurality of row lines and column lines, a column driver circuit, and a row driver circuit. The column driver circuit is coupled to drive column voltage signals over the plurality of column lines; and, the row driver circuit is coupled to activate and deactivate the plurality of row lines with row voltage signals. Significantly, according to the present invention, operational life of the field emission display is substantially extended when the electron emissive elements are intermittently reverse-biased by the column voltage signals and the row voltage signals. In another embodiment, the row driver circuit is responsive to a SLEEP signal.

Abstract: An improvement for a vacuum tube or a plasma tube comprises a cathode loop formed of a material suitable for induction heating. A support structure mounted inside the vacuum tube supports the cathode loop at a cathode position. A power supply mounted outside the vacuum tube includes an induction coil wrapped around the tube near the cathode position and generates an alternating electromagnetic field at the cathode position to induce heat in the cathode loop so that electrons are released into the vacuum tube. Finally, a DC bias is applied to the cathode through the support structure. The improved plasma tube with an induction heated cathode is particularly useful for an ion laser gain medium.

Abstract: Sample material is sputtered from an orifice in a disc mounted in a hollow cathode. A plasma plume is ejected from the orifice and the material sputtered from the smaple is transported directly into the base of the plasma plume. Collisions with particles in the plasma plume excite the sputtered material. Light emission and absorption from the plume are measured and ions in the plume are measured. A chamber surrounding the plasma plume is maintained at about 1 torr. About 15 cc's per minute of argon are supplied to the hollow cathode at 2 torr. The power supply supplies about 200 volts at about 0.10 amps. Low energy argon ions strick the disc at the end of the cathode tube and sputter atoms off the aperture. Atoms collide with particles in the plasma causing excitation, photon emission and ionization of atoms which are measured by optical and mass spectrometers.

Abstract: The present invention provides apparatus for forming electron beams, which may be advantageously employed in many applications, for example in display devices or thyratrons. A cathode member has a hole in its front surface. All the surfaces of the cathode member, except for the wall and base of the holes, are covered in an electrically insulating material such as glass. The cathode member and an anode member are contained within an envelope which also contains a gas filling. On application of a suitably high voltage between the cathode and anode members an electron beam is formed extensive in a direction away from the hole. The anode member may be located behind the front surface of the cathode member, and an electron beam still forms in front of the front surface.

Abstract: A long life high current density hollow cathode electron beam source for use in various E-beam apparatus which uses an ionizable gas within the hollow cathode. Bombardment of an electron emissive surface within the hollow cathode by energetic gas ions causes electrons to be emitted by secondary emission rather than thermionic emission effects. Once initialized by an external ionization voltage the device is essentially self sustaining and operates near room temperature, rather than at thermionic emission temperatures, and with reduced voltages.

Abstract: A novel electrode structure for a fluorescent lamp, particularly one employing a low discharge gas pressure, comprises a directly heated hollow cathode interiorly coated with an emissive mixture. In accordance with one embodiment of the present invention, a flat metal ribbon is wound to form a helix which is heated resistively. In accordance with another embodiment of the present invention, a flat metal ribbon is wound in a flat spiral configuration and likewise heated resistively. In yet another embodiment of the present invention, a fluorescent lamp electrode comprises a metal cylinder heated directly by a filamentary coil disposed about the circumference of the cylinder and electrically insulated therefrom.

Abstract: A hollow cathode electrode, particularly useful in fluorescent lamps, comprises an outer metal sleeve, an inner metal sleeve disposed within the outer sleeve and an emissive mix disposed on the inner sleeve. In one embodiment, the inner sleeve is a folded cylinder having a square cross section disposed within a circular cylinder. The object of the present invention is to prevent heat loss from the inner sleeve and to minimize sputtering. The electrode of the present invention may also include a third exterior sleeve surrounding but not contacting the interior sleeve or sleeves.

Abstract: A lanthanum hexaboride element, typically of cylindrical configuration, is mounted within a high plasma density cathode enclosure. An inlet is provided to supply gas to the cathode enclosure in the vicinity of the lanthanum hexaboride cathode element, and the element is heated to electron-emitting temperature. A plasma utilization chamber is coupled to receive an electron or plasma stream from the cathode enclosure through an aperture of a suitable size to maintain a relatively high plasma density within the cathode enclosure. The plasma density within the cathode enclosure is preferably above the critical level required for high current emission from the lanthanum hexaboride cathode structure. For example this may be in the order of 3.5 times 10.sup.12 electrons per cubic centimeter for a current density of 10 amperes per square centimeter. The lanthanum hexaboride cathode element is supported on notched graphite rings, and the cathode enclosure is made of tungsten.

Abstract: A linear beam tube is provided with a gridded electron gun in which a concave cathode surface is provided with concave channels from which electrons are emitted. The channels may be arranged as concentric annuli. In a preferred embodiment the channels extend radially outwards from the center of the cathode to minimize the effects of temperature distortion. The cathode is provided with a shadow grid and a control grid is spaced from and aligned therewith.

Abstract: Electrodes for high current electric discharges in low pressure gases comprise a heated filament, coated with emissive material and surrounded by a hollow emitting surface in the shape of a truncated cone. The electric discharge initially starts from a spot on the filament and transfers to a diffuse mode at the small end of the cone structure.High current fluorescent lamps which include the electrodes of the present invention are characterized by rapid transition from the spot mode to the diffuse mode discharge and by low cathode fall voltage.

Abstract: A short arc fluorescent lamp comprises an envelope having dimensions compatible with existing incandescent lamp luminaires. A radio frequency power supply, enclosed within the lamp base structure, reduces anode voltage drop to increase lamp efficacy. Cathode voltage drop and sputtering are reduced by compact hollow cathode assemblies, including centrally disposed filaments, which are positioned at opposite ends of a tubular envelope assembly having a large ratio of diameter to length. Diffuse cathode emission allows operation with low pressure, low atomic weight fill gas which further increases luminous efficiency.