Abstract: A color display tube having an electron gun system for producing three in-line electron beams. The system includes, in the direction of travel of the beams, a first electrode, a second electrode and a plurality of focusing electrodes, each having apertures for passing the beams. The second electrode includes two spaced-apart plate-shaped members, each having a central and two outer apertures for passing the beams. The apertures in the members for each outer beam are laterally shifted with respect to each other and with respect to a corresponding aperture in the first electrode to direct the outer beams toward convergence with the inner beam.

Abstract: An electrode of a color picture tube electron gun with a recess provided on the periphery of an electron beam pass aperture, characterized in that the electrode has a thickness of 0.4 to 1.0 times the diameter of the electron beam pass aperture at the portion at which the recess is to be formed and a thickness of 0.1 to 0.2 times the diameter of the electron beam pass aperture at the recessed portion, and the sheet material for the electrode is subjected to plastic working so that the recess forming surface has a thickness of 25 to 50% the thickness of the sheet material or a projection and/or a groove having a section with steeply inclined side portions is provided on both sides of the recess at least in the direction of the width of the recess approximate to the diameter of the electron beam pass aperture.

Abstract: An electron gun with an improved structure for providing accurately adjusted cut-off voltage. A novel process for producing the improved electron gun, and maintain substantially high uniformity of cut-off voltge in production. The electron gun comprises a plurality of grid electrodes including a first electrode mounted at the closest position to a cathode. The cathode is supported by a cathode base. The cathode base and the first electrode are provided in a pre-assembled form. The pre-assembly of the cathode base and the first electrode is supported by means of a holder which is fixed to glass beads together with other grid electrodes. In assembling of the electron gun, the distance between the cathode surface of the cathode and a plane surface of the first grid electrode, where an electron beam path is defined, is precisely adjusted during formation of the pre-assembly.

Abstract: In an electron gun for a color picture tube having three cathodes which are arrayed orthogonally to the axial direction of the tube and at equal intervals on a straight line, and a first grid and a second grid which are successively arrayed and each of which has apertures aligned with electron beam paths corresponding to the three cathodes; the improvement comprising the fact that the surface of at least one of the first grid and the second grid opposing to the other includes aperture-vicinity flats which correspond to the respective apertures, and annular margins which are protruded toward the other opposing grid around the aperture-vicinity flats, and that the annular margin corresponding to the central aperture is retracted from a plane which forms the two annular margins corresponding to the outer apertures, while the aperture-vicinity flats corresponding to the three apertures are so formed as to be substantially coplanar.

Abstract: In electron guns for electronic tubes, such as travelling wave tubes, for power modulating the electron beam, the distance between the cathode and the modulation grid increases the closer to the axis of the tube. Such a gun can be applied to travelling wave tubes operating with a zero enabling voltage and whose modulating frequency covers a very wide band.

Abstract: An inline electron gun for a cathode-ray tube has three cathode assemblies each including a cathode sleeve having a cathode cap closing one end of the sleeve and extending therealong. Each cap has an electron emissive coating thereon and a heater is disposed within each sleeve. The center cathode assembly has a laminated bimetal cathode cap comprising a first layer integral with the sleeve and an overlying second layer with a sidewall portion that is shorter than the sidewall portions of the two outer cathode caps of the outer cathode assemblies. The center cap thus has less thermal mass than the outer caps and the center cathode assembly therefore reaches electron emission temperature before the outer cathode assemblies.

Abstract: Electron gun for cathode ray tube, the electrostatic lenses of which comprise an electrode that remains at a high voltage after shut-down of the power supply of the tube, wherein in order to reduce the effect, apparent through an interference glimmer upon the screen on the K cathode of the high voltage remaining on the electrode after shutdown of the power supply, means for masking this voltage are provided that form part of an electron gun electrode of intermediary position between the first high voltage electrode and the cathode, and wherein preferably, the intermediary electrode has an elongated form according to the axis of the gun with two end walls, of which that turned towards the cathode has a greater thickness than the thickness of the opposite wall.

Abstract: An improved grid arrangement is shown for a gridded electron gun wherein the control grid and/or shadow grid is provided with tapering grid vanes which reduce the amount of voltage required to cut off the electron beam. Alternately, a fewer number of grid vanes may be utilized to accomplish the same cutoff of the electron beam thus reducing the loading on the cathode and improving the transmission of the electron beam.

Abstract: The structure is material such as a ceramic in the form of a bundle of open cells, a "honeycomb", with the shape of the cells corresponding to the shape of the openings desired in the grid. The cathode is formed in the cells, rather than adding the grid to a ready-made cathode. The grid is formed by coating the end of the cell walls with a conducting material (metal and/or carbon). The surface of the cathode is suitably recessed from the grid.

Abstract: An electron gun includes a preferably non-metallic apertured grid with a flat upstream-facing surface closely spaced from and parallel to a flat emitting surface of a cathode. The grid aperture diverges in a downstream direction and has its peripheral wall contoured to shape the transverse cross-section of an emitted electron beam at a predetermined downstream location, preferably at the beam crossover. The peripheral wall of the grid aperture is devoid of sharp transitions, has a circular cross section to produce a circular beam crossover of minimum diameter, and has a convex segment extending from the upstream end of the aperture and joining a concave segment extending to the downstream end of the aperture. The convex first segment has a smaller radius of curvature than the second concave segment and has its center of curvature disposed substantially at the upstream facing surface.

Abstract: A circuit assembly for temperature-dependent cathode current tracking in traveling-wave tubes having control electrodes and cathodes with a predetermined cathode current, in combination with a power supply, includes a temperature-dependent network thermally coupled to a given point of the traveling-wave tube for measuring the actual temperature of the tube, and an electronic control circuit in the power supply connected to the temperature-dependent network for keeping the predetermined cathode current substantially constant by varying the voltage at the control electrode of the tube.

Abstract: The novel electron gun comprises, as in prior guns, a plurality of cathode assemblies and at least two spaced successive electrodes having aligned apertures therethrough for passage of a plurality of electron beams. The cathode assemblies and the electrodes are individually held in position from a common ceramic member. The ceramic member has a first major surface and an oppositely disposed second major surface with a metallized pattern formed on at least a portion of each major surface. The electrodes are attached to the first major surface, and the cathode assemblies are attached to the second major surface. A transition member is attached to the metallized pattern on the first major surface. The transition member includes a substantially flat portion attached to the metallized pattern on the first surface and two upright portions substantially perpendicular to the flat portion and substantially parallel to each other.

Abstract: The novel electron gun comprises, as in prior guns, a plurality of cathode assemblies and at least two spaced successive electrodes having aligned apertures therethrough for passage of a plurality of electron beams. The cathode assemblies and the electrodes are individually held in position from a common ceramic member. The ceramic member has a first major surface and an oppositely disposed second major surface with a metallized pattern formed on at least a portion of each major surface. The electrodes are attached to the first major surface, and the cathode assemblies are attached to the second major surface. A transition member is attached to the metallized pattern on the first major surface. The transition member includes a substantially flat first part and a second part electrically isolated from the first part.

Abstract: A multibeam electron gun comprises two spaced successive electrodes individually held in position from a common electrically-insulating support. Each of the electrodes has at least three beam-defining apertures therein. Each of the electrodes also has two dissimilarly shaped alignment apertures therein which are mutually aligned so that the beam defining apertures are accurately aligned along common axes in a statically determined manner.

Abstract: A multibeam electron gun comprises two spaced successive electrodes individually held in position from a common electrically-insulating support. One electrode comprises a single metal plate having at least three electron-beam defining first apertures therein. The other electrode is a composite structure comprising a support plate and a second metal plate having at least three electron-beam-defining second apertures therein. Each of the first and second plates includes substantially triangularly-shaped alignment apertures which are mutually aligned so that the beam-defining apertures are aligned along common axes.

Abstract: The horizontal and vertical deflection factors for a split anode beam penetration color CRT are compensated for changes and remain constant as trace color is varied. In an electro-statically deflected tube a correction lens near an expansion mesh and electrically connected to the split anode faceplate alters the radial velocities of electrons leaving the mesh such that their point of impact upon the faceplate is unaffected by changes in axial velocity induced to change trace color. In a magnetically deflected tube a correction lens in the neck near entrance to the deflection yoke is supplied with a voltage that varies in conjunction with that of the faceplate. The axial velocity of the electrons in the region of magnetic deflection is adjusted to produce amounts of deflection that remain constant despite changes in the faceplate voltage.

Abstract: An improved electron gun is shown with a cathode having a smooth, concaved surface and a grooved pattern therein which matches, and is aligned with, the pattern of a shadow grid placed immediately before the cathode surface so that the outer, larger radius of curvature of the shadow grid closest to the cathode is substantially identical and concentric with the radius of curvature of the smooth, concave cathode surface. Beyond the shadow grid is a control grid which controls the flow of electrons emitted from the cathode toward an anode. The grooves which form the pattern within the cathode surface have tapered side walls and rounded outer and inner corners to improve the flow of emitted electrons and facilitate manufacture.

Abstract: A cathode and grid assembly includes a first grid of small diameter secured to a planar inner surface of a ceramic means and over a central opening in the ceramic means and a second grid having a first planar section secured to a planar outer surface of the ceramic means, a second planar section positioned within the central opening and a frustum of a cone section interconnecting the first and second planar sections with the frustum of a cone section extending along a frustum of a cone outer surface of the ceramic means.

Abstract: A multibeam electron gun comprising two spaced successive electrodes individually held in position from a common support. One electrode comprises a single metal first plate having at least three electron-beam-defining first apertures therein. The other electrode is a composite structure comprising (a) a single metal second plate having a window therein opposite each of said first apertures and (b) a separate metal third plate attached to said second plate closing each of the windows. The third plate has a single electron-beam-defining second aperture therein separately aligned with one of the first apertures.

Abstract: Apparatus for compensating the injurious increase of the cathode current occurring during the initial operation period of a travelling-wave tube when, during successive warming-up, the grid first approaches the cathode and then assumes the nominal distance therefrom. The apparatus includes a distance control device measuring the deviation between the actual grid-cathode distance and the nominal distance and generating a control signal proportional to the deviation for reducing the value of the grid voltage.

Abstract: An in-line electron gun assembly for a color television picture tube has a control grid and a center cathode disposed between two outer cathodes. The control grid and the cathodes are secured to a pair of insulating support rods. Each cathode is supported by a cathode support assembly comprising a cathode eyelet and a beading support member. Each beading support member varies in dimensions as a function of temperature and the center beading support member stabilizes at a higher operating temperature than the outer beading support members. The ends of the beading support members are embedded in a pair of oppositely-disposed insulating support rods. The center beading support member is formed of a material having a high thermal expansion coefficient and the outer beading support members are formed of a material having a lower thermal expansion coefficient.

Abstract: Critical spacings between the cathode and grid of an electron gun structure are enabled by a cathode structure including a removable spacer, such structure produced by first forming a layer of potentially electron emissive material on the cathode, then forming a solvent drop on the layer, and contacting the drop with a spacer to adhere the spacer to the layer.

Abstract: An electron gun comprises a cathode for generating at least one electron beam along a beam path and a plurality of electrodes spaced along the beam path from the cathode. The electrode adjacent to the cathode comprises an electrically conductive base member of a first material having an aperture extending therethrough. The base member has two opposing surfaces that have overlying layers of a second electrically conductive material disposed thereon. The overlying layers overhang the aperture in the base member. At least one of the overlying layers has a plurality of apertures therethrough.

Abstract: A variety of technologies have been applied in the development of a bonded rid cathode. Erosion lithography is used for making the fine-detail grid structure, combining air erosion and lithographic techniques. To obtain openings of the order of 0.001 inch (one mil) or smaller, a nozzle with a high aspect ratio exit opening is used, and the cathode grid structure is scanned. A photo resist in which the grid pattern is developed is used over the molybdenum or tungsten grid film. The metal film is removed from the grid openings by chemical etching. The photo resist over the metal grid is used as a composite mask for removing the BN insulation in the openings by erosion with Al.sub.2 O.sub.3 powder from the special nozzle on the air blast gun.

Abstract: A gun for a linear-beam electron tube has a control grid for modulating the beam current which consists of an array of conductive web elements whose spacing from each other is much larger than their spacing from the concave emissive surface of the cathode. It was found that when this condition is met the grid can be operated at cathode potential while beam current is being drawn without distorting the electric accelerating field enough to ruin the focusing of the beam. Thus, when the grid is used to pulse the beam current on and off, it can have zero bias in the "on" condition, whereby the pulse modulator can be greatly simplified.

Abstract: An electron gun for a camera tube includes an anode and a cathode. The cathode is assembled in a cathode support which can very readily be adjusted relative to the anode in the nonconnected condition. In particular, the cathode support and the anode are movable radially with respect to each other and with respect to an axis. An emissive cathode surface and a part of the anode extending perpendicular to the axis remain accurately parallel to each other during the radial movement. As a result of this it is possible to cause the central path of the generated electron beam and the gun axis to coincide so that extra correction coils for aligning the electron beam may be omitted.

Abstract: The invention relates to metal oxide activated porous tungsten cathodes and methods of their manufacture. A cathode 1 of porous tungsten activated by metal oxides is mounted on a housing 2 which has a heating filament 3. On the outer face of the cathode there is a pattern or grid of pure tungsten (preferably formed by a chemical vapor deposition of WCl.sub.6 or WF.sub.6) of crystalline material the outer face of which has an orientation in the (100) or (110) plane and is parallel to the surface of the cathode. The invention will find particular use in the cathode guns of high frequency tubes such as traveling wave tubes and klystrons.

Abstract: A one-piece control grid for functioning as an astigmatic lens in an electron gun has a milled, ground, or machined slot formed across its functional grid area. A suitable beam aperture is provided in the bottom of the slot.

Abstract: The haze around the electron beam spot in the corners and at the edge of the display screen is reduced by using in the electron gun a first grid of a construction such that a multipole lens which is mainly a first quadrupole lens is formed in cooperation with the cathode. The first grid in cooperation with the second grid also forms a multipole lens which is also a mainly second quadrupole lens and which is rotated 90.degree. with respect to the first quadrupole lens. Such a system of lenses in the first grid can be formed, for example, by providing in the first grid an aperture with elongated openings both on the side of the cathode and on the side of the second grid. The longitudinal axis of the elongated opening on the side of the cathode is substantially at right angles to the longitudinal axis of the elongated opening on the side of the second grid.

Abstract: A gun for a linear-beam electron tube has a control grid for modulating the beam current which consists of an array of conductive web elements whose spacing from each other is much larger than their spacing from the concave emissive surface of the cathode. It was found that when this condition is met the grid can be operated at cathode potential while beam current is being drawn without distorting the electric accelerating field enough to ruin the focusing of the beam. Thus, when the grid is used to pulse the beam current on and off, it can have zero bias in the "on" condition, whereby the pulse modulator can be greatly simplified.

Abstract: An electron gun structure which includes at least one cathode electrode, a plurality of grid electrodes including a first grid electrode, and a heater coil. The cathode electrode consists of a tubular cathode sleeve and an electron emissive coating formed on the closed end of it. The heater coil is positioned within the cathode sleeve and has legs welded to heater supporting straps. The surfaces of the heater straps adjacent the cathode sleeve are constructed such that the arcing start potential between the cathode electrode and the heater supporting straps is lower than the arcing start potential between the cathode electrode and the heater coil, thereby preventing arcing to the heater itself.

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: An electron beam producing arrangement for a cathode ray tube comprises a vessel shaped control electrode with a bore therein for passage of the electron beam and a hat shaped metal foil element with its crown in the bore and apertured for the passage of the electron beam and fixed to the edge of the bore by its brim.

Abstract: For a grid-controlled electron source to operate at extremely high frequencies, as in planar triodes, the control grid must be situated very close to the emissive cathode. Mechanical and thermal distortions have put minimum limits on grid spacings and hence on the maximum operating frequency of grid-controlled tubes. To overcome these limits the grid structure is formed as a network of web members which are part of a laminated sheet having metal layers bonded to opposite surfaces of an insulating layer. One metal layer is affixed to the emissive surface of a metallic matrix cathode and the other metal layer forms the control grid.

Abstract: An electron beam producing arrangement for a cathode ray tube comprises a vessel-shaped control electrode with an opening in its end wall for the passage of the electron beam, two substantially rectangular insulating washers abutting a cylindrical inner wall of the control electrode with opposite sides and the end wall of the control electrode with third sides, the third sides having notches thereon and a straight line cathode wire supported in the notches substantially parallel to the end wall and below the opening therein.

Abstract: An in-line electron gun assembly for a color television picture tube has a center cathode disposed between two outer cathodes. The cathodes are substantially coplanar and each is supported at a predetermined distance from a control grid by a separate cathode support structure. Each cathode support structure includes a cathode eyelet. The center cathode eyelet is formed of a material having a smaller coefficient of thermal expansion than that of the two outer cathode eyelets so that the variations in carthode-to-grid spacing due to temperature changes during warm-up are kept substantially equal from cathode to cathode.

Abstract: In a color cathode-ray tube, the neck of the tube comprises an assembly of three electron guns lying in one plane. The size of the assembly is reduced by using oval control electrodes the longer axes of which are perpendicular to the plane through the electron guns.

Abstract: A grid-controlled electron source comprises an apertured grid spaced in front of a thermionic cathode. Areas of the cathode directly behind the grid conductors are made non-emissive by a bonded surface layer of non-emissive material such as zirconium. On porous metal cathodes impregnated with active emitting material the metal surface may be sealed with a dense layer of inactive metal under the non-emissive layer to prevent chemical reaction of the latter with the emitting material.Methods of depositing the surface layers in the desired pattern include coating the cathode's entire large-scale surface contour, followed by machining small concave dimples into the surface, thereby removing the non-emissive layer from the dimpled surfaces from which small beamlets of electrons are focused between the grid conductors without grid interception.Another method is to mask the desired non-emissive areas with an apertured mask having solid elements registered with the desired positions of the grid conductors.