Abstract: A color cathode ray tube including a panel section having a phosphor layer formed on an internal surface thereof, a neck portion having an electron gun assembly for emission of three electron beams therein, and a funnel section connecting the panel section and the neck portion. The electron gun assembly includes three cathodes and a plurality of grid electrodes disposed along a tube axis. The grid electrodes includes at least one plate-shaped electrode which has a fixed support structure. The plate-shaped electrode has three bulged portions along an electron beam passage, a first electron beam passage hole being formed in a respective bulged portion and a second electron beam passage being hole formed in a top face portion of a respective bulge portion. A diameter of the first electron beam passage hole is greater than a diameter of the second electron beam passage hole.

Abstract: An electron gun assembly includes a plurality of cathodes arranged in an in-line direction, at least first through fourth grids having electron beam passing holes arranged in an in-line direction, and an insulation support for sandwiching the cathodes and the grids between and fixing the cathodes and the grids from a direction perpendicular to the in-line direction. The second grid and the fourth grid are supplied with substantially the same low potential, the third grid is supplied with a potential higher than the potential of the fourth grid, and the second grid is fixed to the insulation support on a side of the third grid. The third grid has a cup-shaped electrode on a side of the second grid, the cup-shaped electrode including a plane portion having electron beam passing holes, an opening portion, and planting portions planted in the insulation support.

Abstract: A cathode-ray tube according to the present invention is able to automatically correct a color shading caused due to a repulsion effect and the like, which occurs between electron beams. An electron gun for use with the cathode-ray tube according to the present invention includes beam apertures bored through a first electrode opposing a cathode disposed in an inline fashion. Further, beam apertures through which so-called side beams pass are bored with a predetermined inclination relative to the opposing cathodes. Consequently, an electron lens formed between the cathode and the first electrode becomes an axial asymmetric electron lens. A curvature of this electron lens is changed in response to a drive voltage of the cathode. When this curvature is changed, trajectories of electron beams are changed to cancel an influence caused by a repulsion effect. Thus, a color shading can be corrected automatically.

Abstract: In an electron tube based on a cold cathode, a cesium source (17) containing Csx—Auy or Csx—Sby is provided near the cold cathode (7), preferably in contact with the first grid (9). Cesium is introduced into the source during activation of the tube. The vapor pressure of the cesium compounds is such that proper delivery of cesium is guaranteed throughout the life-time of the cathode.

Abstract: A color cathode ray tube includes a panel section having an internal surface with a phosphor layer formed thereon and a neck portion accommodating therein an electron gun assembly for emission of a plurality of electron beams plus a funnel section connecting the panel section and the neck portion together, wherein the electron gun assembly is designed to have a plate-shaped electrode with a plurality of electron beam passage holes corresponding in the number to the electron beams. The plate electrode has cylindrical bulged portions projecting in a way corresponding to the plurality of electron beams, each of which portion has its top face in which an electron beam opening or hole is formed. The present invention provides a color cathode ray tube comprising a readily manufacturable high-resolution electron gun assembly.

Abstract: A method for manufacturing an electron gun for a cathode ray tube. The method comprises a first step in which a number of securing means are made in a planar element (e.g. plate or strip), a second part in which the securing means are secured to an insulating support rod, a third part in which the insulating support rod-securing means assembly is detached from the planar element, whereafter connections are made to a stack of electrodes to form the electron gun.

Abstract: An electron gun for a color cathode ray tube contains a cathode, first grid, second grid and third grids, sequentially disposed between the cathode and a screen, and wherein the vertical length of electron beam passing hole formed on the first and third grids is longer than the horizontal length thereof and the vertical length of an electron beam passing hole formed on the second grid is shorter than the horizontal length thereof.

Abstract: Picture display device comprising an electron gun with cathodes having an enhanced dissipation of heat by virtue of an enlarged surface or an increase of the emissivity of the surface.

Abstract: A linear beam amplification device includes an axially centered electron emitting cathode and an anode spaced therefrom. The cathode provides an electron beam in response to a relatively high voltage potential defined between the cathode and the anode. A control grid is spaced between the cathode and anode for modulating the electron beam in accordance with an input signal. A signal input assembly of the linear beam amplification device comprises an axial input cavity into which the input signal is inductively coupled. The grid-cathode region is electrically connected to the input cavity. A low impedance grid-anode cavity is disposed coaxially with the input cavity and is in electrical communication with an interaction region defined between the grid and the anode. The low impedance of the grid-anode cavity is provided by constructing the cavity of a material having a relatively high surface resistivity, such as iron.

Abstract: A cathode-ray tube is provided with an electron gun having a cathode and a control electrode and some other electrodes. The cathode includes an electron emissive material layer for emission of electrons through a hole in the control electrode. The hole in the control electrode has a diameter substantially in a rage of from 0.3 mm to 0.4 mm. The electron emissive material layer has a first layer made of an oxide of an alkaline earth metal formed on a support and containing no oxide of a rare earth metal, and a second layer made of an oxide of an alkaline earth metal formed on the first layer and containing an oxide of a rare earth metal substantially in an amount of from 0.8 wt % to 5.0 wt %.

Abstract: An improved inline electron gun includes a plurality of electrodes spaced from three cathodes in the direction of a longitudinal axis of the gun. The electrodes form at least a beam forming region and a main focus lens in the paths of three electron beams, a center beam and two side beams. Each of the electrodes includes three inline apertures therein for passage of the three electron beams. The beam forming region includes the cathodes and three consecutive electrodes, a G1 electrode, a G2 electrode and a G3 electrode. The improvement comprises the G2 electrode having two linear projections on either side of the inline apertures therein. The projections parallel the inline direction of the apertures protrude in a direction parallel to the longitudinal axis, past the apertured portion of the G3 electrode in overlapping relationship therewith. On the side of the G3 electrode facing the G2 electrode, the G3 electrode has two linear channels therein on either side of the inline apertures therein.

Abstract: An electron gun provides an improved focusing characteristic of electron beams surely and effectively, and permits position alignment to be relatively easy in assembling thereof. In an electron gun which includes a cathode for discharging electrons and a plurality of grids each having electron passing-through holes for guiding the electrons discharged from the cathode unidirectionally, an electron dischargeable region is formed in an electron discharging plane of the cathode, which is band-shaped. In addition, the length of the band-shaped area constituting the electron dischargeable region on its shorter side is less than 80% of the diameter of the area from where electrons are discharged when a practical maximum current is taken out without limiting the electron dischargeable region.

Abstract: A grid support structure is provided for a linear beam device having an axially centered cathode, an anode spaced therefrom and a grid disposed between the cathode and anode. The grid support structure maintains a proper grid-to-cathode spacing across an operating temperature range of the linear beam device. The grid is comprised of pyrolytic graphite, and includes a central active portion and a peripheral portion, with the peripheral portion comprising a plurality of evenly spaced elongated mounting holes. The grid support structure includes an inner grid support and an outer grid support. The inner grid support may include a plurality of axially extending posts that engage the mounting holes of the grid. The grid may further include resilient tabs that engage corresponding ramped surfaces to bias the grid into position.

Abstract: A one-piece grid assembly for use in an electron gun for a miniature cathode-ray tube application that consists of a core made of an electrically insulating material, a first grid deposited on the core, and a second grid deposited on the core that is spaced apart from the first grid, and a method of making the one-piece grid assembly by first compression molding the core and then depositing the grid by plating are disclosed.

Abstract: An electron gun provides multiple convergent beamlets in a rectilinear flow for use in multiple drift tubes of a multiple beam klystron. The electron gun comprises a cathode having a concave emitting surface and an anode having a concave surface defined by respective ends of a plurality of hollow drift tubes. The anode surface is spaced from the cathode surface and has a positive voltage potential applied thereto to define a series of equipotential contour surfaces between the cathode and the anode. A plurality of grids are located between the cathode and the anode, with each one of the grids being disposed coincident with a respective one of the equipotential contour surfaces with a first one of the grids located closely adjacent to the cathode surface. Each one of the grids further has a plurality of perforations extending therethrough in substantial registration with each other and with respective openings of the plurality of drift tubes.

Abstract: An electron gun for a color cathode ray tube includes a cathode structure having three electron emitting portions in a field emission array cell. A focus electrode and a final acceleration electrode are sequentially arranged with respect to the cathode structure and form a main lens for focusing electron beams emitted from the three electron emitting portions. The eccentric distance of the electron emitting portions is shorter than the eccentric distance of the electron beam emitting holes in the focus electrode opposite the electron emitting portions. Focus characteristics and convergence characteristics are improved.

Abstract: An electron gun is provided, in which a capacitance between a cathode and other electrodes, especially a control electrode is reduced largely without substantially changing a structure for supporting the cathode with an insulator. The cathode of this electron gun is disposed inside of the cylindrical metal shell. The cathode and the cylindrical metal shell are connected by three metal tabs. The cylindrical metal shell fits into a hole formed in the center portion of the insulator, and a metal outer frame is attached to the periphery of the insulator. The metal outer frame is welded to the inner surface of a cathode metal support. There is a control electrode facing the electron emitting surface of the cathode at a predetermined distance. Plural electrodes including an accelerating electrode are disposed in turn beyond the control electrode.

Abstract: In an electron gun for a cathode ray tube in which a focus electrode group includes a single platelike electrode having three apertures arrayed in one plane and a thickness equal to a depth of each of the three apertures, a tapered surface is formed on the entrance side and/or exit side of each of the three apertures, the tapered surface having a diameter larger than the aperture diameter and having a linear or curved shape in cross section, and a step which extends in the direction of the depth is formed around an aperture periphery of the tapered surface. With this constitution, the concentricity between each of the tapered surfaces and a respective one of the apertures can be measured with high precision on the basis of the boundary between each of the tapered surfaces and the corresponding one of the steps, thereby improving the precision of measurement of the concentricity between each of the apertures formed in the platelike electrode and the tapered surface formed around the aperture periphery.

Abstract: An electron has an electron-emitting region, a longitudinal axis and an arrangement of apertured electron grids along the axis. A first grid has an aperture for passing electrons, which aperture is located further outwards with respect to the longitudinal axis than the emitting region. One of the other grids is provided with a shield so as to shield the edge wall of the aperture, if it is located within direct view of the electron-emitting region, from incidence of positive ions.

Abstract: A broad-beam high energy electron accelerator has an electron injection section arranged for increased current density with greater uniformity and higher transmission through the foil exit window. A plurality of cathode rods are disposed in a transverse plane and spaced at about 2.4 cm, and a reflector plate behind the cathode rods is biased negative relative thereto. A planar control grid is disposed distal of said cathode rods and a screen grid is disposed parallel to and distal of the control grid. Field-shaping wires are disposed in a plane parallel to the plane of the cathode rods and between the same and the reflector plate, with the respective field-shaping wires being disposed parallel to said rods and midway between them. The same positive bias (e.g., 11 kV) is applied to both the control grid and the field-shaping wires.

Abstract: A deformation produced by heat when a G1 grid is welded can be suppressed. A U-shaped slit (34) is formed on an outer peripheral wall (31) of a G1 grid (12). A spot-welding portion (X) is set to an end edge of a joint portion of the U-shaped slit (34) and this spot-welding portion (X) is spot-welded to a retainer (22) of a cathode (21) by a laser beam. In the G1 grid (12), the deformation produced by heat upon welding is absorbed by the surrounding portions of the slit (34). Therefore, it becomes possible to prevent the opposing surface opposing a G2 grid (13) from being expanded by heat. Thus, the spacing between the electrodes can be maintained to be a proper one and the angles of the electron beam emitting apertures can be maintained at proper ones. Therefore, it becomes possible to prevent the characteristic of the electron gun and the resolution of the cathode ray tube from being deteriorated.

Abstract: A vacuum tube for handling an r.f. signal having a predetermined frequency range comprises a cathode, a heater, and a non-electron emissive grid. The grid is positioned from the cathode by the distance an emitted electron from the cathode can travel in a quarter cycle of the r.f. signal. Outer and inner metal tubes forming a resonant line of a signal coupler are respectively connected to the grid and cathode. R.F. absorbers absorb r.f. fields in an interaction region between an anode and the grid. In one embodiment a coupling loop is between metal tubes at an end of the tubes spaced n.lambda./4 from the grid and cathode. In a second embodiment the coupler includes a coaxial line having an inner conductor connected to a first metal face, spaced from a second opposed metal face by a solid dielectric. An outer conductor is connected to a third metal face, spaced from a fourth opposed metal face by the dielectric. The third and fourth faces surround the first and second faces.

Abstract: A grid electrode for a cathode ray tube includes a ceramic carrier lamina having a thickness of up to about 0.5 mm and opposite lamina surfaces; a throughgoing aperture defined in the carrier lamina by a wall portion thereof extending between the lamina surfaces; and a metallized surface portion forming part of one of the lamina surfaces. The metallized surface portion is situated in a zone of the aperture.

Abstract: A field emission cold cathode includes a conductive substrate (1), an insulating layer (2) disposed on the substrate (1), a gate electrode (3) disposed on the insulating layer (2), cavities (4) extending through the gate electrode (3) and the insulating layer (2), and emitter cones (6) disposed on the substrate (1) within the cavities (4). The gate electrode further includes high resistance areas (5) disposed around the tips of the emitter cones (6) that enables the field emission cold cathode to operate in the event of a short circuit between the gate electrode (3) and an emitter cone (6) due to electrically conductive foreign material entering a cavity (4). The field emission cold cathode can be use in an electron gun.

Abstract: A color cathode ray tube (CRT) includes a multi-beam electron gun capable of operating in two or more modes for use as either a television receiver display or as a high resolution video monitor. The electron gun directs a plurality of electron beams onto the CRT's display screen, with the electron beams arranged in two or more groups. In one group of electron beams, the beam forming portion of the electron gun provides small diameter electron beams having reduced spot size on the CRT's display screen for high video image resolution when used as a monitor for graphics and/or character display. In another group of electron beams, the beam forming portion of the electron gun provides electron beams having a larger diameter and current for increased video image brightness when used as a television receiver. Each group of electron beams includes a plurality of horizontally aligned electron beams, with each beam providing one of the primary colors of red, green, or blue.

Abstract: A high efficiency linear amplifier comprises an electron gun assembly having a cathode and an anode, the cathode being operable at a relatively high voltage potential relative to the anode to form and accelerate an electron beam. A control grid is disposed between the cathode and the anode, and is biased relative to the cathode for Class B operation. A high frequency input signal is applied to the control grid to density modulate the electron beam. A shadow grid may be disposed between the control grid and the cathode. A drift tube encloses the beam and includes a first portion and a second portion with a gap defined between the first and second portions. An inductive output cavity communicates with the gap, and the density modulated electron beam passed across the gap and induces an RF electromagnetic signal into the cavity. A multistage depressed collector accepts and dissipates the electrons of the beam which remain after transit across the gap.

Abstract: An electron beam aperture of a second grid electrode of a color cathode ray tube is a rectangular hole formed in the center of a slit-like recess having longer sides extending in the horizontal direction. The vertical width of the rectangular hole is greater than the width of each shorter side of the slit-like recess.

Abstract: An electron gun for use in remediation of hazardous volatile organic compounds is provided. The electron gun comprises a cathode having a concave emitting surface and a dome-shaped focusing electrode concentrically surrounding the emitting surface. The focusing electrode has an inwardly protruding lip portion that extends at least partially into a beam focusing region defined in front of the emitting surface. A target grid is spaced from the cathode and a negative voltage is applied between the emitting surface and the target. The target grid has a surface area that is substantially larger than an associated surface area of the emitting surface. An electron beam is provided by the emitting surface in response to the negative voltage, and is focused into a broad diverging beam by the focusing electrode. The electron gun may be configured for temperature limited emission or space charge limited emission.

Abstract: An electron gun for a color cathode ray tube having a cathode, a control electrode and a screen electrode together constituting of a triode, and a main lens for focusing and accelerating an electron beam formed by the triode. The electron gun is characterized by a horizontally elongated electron beam passing hole formed in the control electrode having its long axis disposed in the arrangement direction of the electron beam passing hole. A horizontally elongated slot encompassing the electron beam passing hole having its long axis disposed in the arrangement direction of the electron beam passing hole is formed in the screen electrode opposed to the control electrode, thereby preventing the focusing characteristics of the electron beam from being reduced throughout the surface of the fluorescent layer by the influence of the deflection yoke.

Abstract: An electron gun for a color cathode-ray tube reducing the spherical aberration and the flying spot aberration, thus improving the resolution of the color cathode-ray tube. The electron gun comprises a pair of accelerating/focusing electrodes coaxial with the tube and providing a passage for the electron beams. The electrodes are spaced apart from each other by a predetermined distance and has individual common openings, and each includes an envelop having a rim adjacent a corresponding common opening, the rim surrounding the plurality of electron beams and defining the common opening, and a control electrode plate being placed in the envelop and recessed from the rim by a predetermined distance in the axial direction in order for controlling the plurality of electron beams. Each electrode plate has a center opening and a pair of opposed outer openings. The center opening may be a rectangular opening or rounded at its upper and lower ends.

Abstract: A flat panel device contains a faceplate, a backplate, a light-emitting mechanism, and a spacer. The faceplate is connected to the backplate to form a sealed enclosure. The spacer is situated within the enclosure and supports the two plates against forces acting towards the enclosure. The spacer can take various forms and can be constituted with various materials. In one embodiment, the spacer includes a spacer wall formed with multiple sheets of laminated material consisting of ceramic, glass-ceramic, ceramic reinforced glass, devitrifying glass, or metal coated with electrical insulation. In another embodiment, the spacer includes a spacer wall having a surface that follows a non-straight path adjacent the faceplate. In yet another embodiment, the spacer is a spacer structure through which a plurality of holes extends. The light-emitting mechanism is typically implemented with an electron-emitting cathode and light-emissive material situated over the faceplate.

Abstract: The frequency of an AC signal is multiplied by a factor N, where N is an integer greater than one, by an electron tube including a cathode for emitting an electron beam and a grid including N segments in proximity to the cathode. The grid is biased and coupled to the signal so the beam is formed as N groups of electron bunches during each cycle of the signal. Each segment accelerates one group of bunches for a duration of about 1/N th of each cycle of the signal. Different groups of bunches associated with the different segments are accelerated at phases displaced from each other during each cycle of the signal. In response to the N groups of bunches an output signal having a frequency N times that of the signal is derived.

Abstract: A vacuum tube for handling an r.f. signal having a predetermined frequency range comprises a linear electron beam emitting cathode, a heater and a non-electron emissive current modulating grid. The grid is positioned from the cathode by the distance an emitted electron from the cathode can travel in a quarter cycle of the r.f. signal. Outer and inner coaxial metal tubes forming a resonant line of a signal coupler are respectively connected to the grid and cathode so electrons passing through the grid are in bundles in an interaction region between an accelerating anode and the grid. Ferrite tiles absorb r.f. fields in the interaction region. In one embodiment a signal coupling loop is between metal tubes at an end of the tubes spaced 3.lambda./4 from the grid and cathode. In a second embodiment the coupler includes a low voltage coaxial line having an inner conductor connected to a first metal face, spaced from a second opposed metal face by a solid dielectric.

Abstract: An electron gun cathode structure includes a support member made of an insulating material, a first grid fixed to the support member, and a cathode disposed on the side of the support member opposite to the first grid. A thermal expansion .DELTA.L.sub.s /L.sub.s of the insulating material constituting the support member due to heat from the cathode is larger than a thermal expansion .DELTA.L.sub.G /L.sub.G of a material constituting the first grid due to heat from the cathode. A manufacturing method of an electron gun cathode structure includes preparing a member including a first face and a second face having a step therebetween, a height of the step being equal to a predetermined distance d.sub.12, placing a first grid on the first face, placing a spacer on the second face, placing an insulating support member on the first grid and the spacer, and grinding a top surface of the spacer opposite to its surface that is fixed to the support member so that an actual distance d.sub.12 becomes a desired value.

Abstract: An inline electron gun for use in a multi-beam color cathode ray tube (CRT) has a main focus lens for focusing the electron beams on a display screen of the CRT. The main focus lens includes adjacent charged electrodes each having a respective common lens aperture through which the electron beams are directed and which are in facing relation for reducing horizontal spherical aberration of the electron beams on the display screen, where each common lens aperture has a longitudinal axis aligned with the inline electron beams. In one embodiment, each common lens aperture is chain-link-shaped including spaced, vertically enlarged portions, each aligned with a respective electron beam for correcting for vertical spherical aberration. Each adjacent electrode further includes a plurality of auxiliary apertures, each aligned with and passing a respective electron beam.

Abstract: In a cathode assembly of a cathode ray tube, a cathode having an emitter is inserted in a through-hole formed in an insulator. The emitter is provided so as to face a cylindrical electrode of a first grid at a predetermined distance. A hole communicating with the through-hole is formed at a longitudinal side of the insulator, and a tubularly rising shelter is provided between the emitter in the through-hole of the insulator and the hole. This satisfies (E.times.B)-(C.times.E)+(C.times.D)-(A.times.D).gtoreq.A. D, where the height of the hole is A, the height of the shelter is B, the length from the lower end of the shelter to the head of the cathode is C, the length between the cathode and the shelter is D, and the length between the cathode and the insulator is E. The cathode assembly prevents metal vapor, such as barium oxide of the cathode and nickel or chromium of the sleeve, from spreading through the hole of the insulator.

Abstract: An electron gun comprises a cathode made of an emissive material with an active face emitting electrons through a control grid that is placed before the active face but has no contact with it. The active face has emissive zones and non-emissive zones. The non-emissive zones are formed by grooves hollowed out of the emissive material. The control grid has solid parts that directly face the grooves. Application to electron guns with reduced heating of the control grid. FIG. 5 .

Abstract: An electron gun such as used in a cathode ray tube (CRT) includes an Einzel lens having charged G3, G4 and G5 grids for focusing an electron beam on the CRT's display screen. The G3, G4 and G5 grids are cylindrical and have the same inner diameter, with their respective longitudinal axes colinear and aligned with the electron beam axis. Where T is the thickness of a grid and L is the G3-G4 or G4-G5 spacing, or gap, shielding against stray electrostatic fields within the grids arising from stray electrons on either a grid-supporting glass bead or on the inner surface of the CRT's neck portion is provided by maintaining the relationship 3.0.gtoreq.T/L.gtoreq.0.75. Another embodiment employs thinner grids having a thickness t with outward turned end flanges, or folded edges, disposed about facing edges of adjacent grids having a thickness T, where T>t and the above-stated relationship of T/L is maintained.

Abstract: A multi-beam electron gun for a color cathode ray tube (CRT) includes a plurality of vertically spaced, horizontal inline beams, where each inline array of beams provides the three primary colors of red, green and blue and adjacent inline beam arrays simultaneously trace adjacent horizontal scan lines on the color CRT's display screen. The beams in each horizontal inline array of beams are focused on a common spot on the display screen, with the three beams deflected across the screen in unison. Each inline array of beams is modulated in accordance with that portion of the video image which they form allowing adjacent, vertically spaced inline arrays to write different video image information on the screen in simultaneously forming adjacent portions of the color video image.

Abstract: A system for controlling the shape of a charged particle beam. The particle beam is emitted from a source (58) of the said particles. Said source is associated with a collecting electrode which collects the particles. The system comprises at least one resistive zone (56) and at least two control electrodes (52, 54). The resistive zone and the control electrodes are arranged substantially at the same level as the source. The control electrodes are also placed on either side of the resistive zone and serve to polarize the latter. The electrical resistance profile of the resistive zone is chosen in such a way that it has the potential distribution so that it is possible to obtain the desired shape of the beam from the source when the control electrodes are appropriately polarized.

Abstract: A vacuum tube for amplifying an r.f. signal includes an assembly containing a cathode and grid for current modulating an electron beam derived from the cathode. One of the electrodes of the assembly includes a slow wave structure approximately resonant to the frequency of the signal. A cavity resonant to the frequency of the signal, positioned between the grid and a collector for the beam, is coupled to the beam. In one embodiment, the slow-wave structure is mounted in a support for the grid, while in a second embodiment, the grid is configured as plural, parallel meander lines forming the slow-wave structure. In the latter embodiment, the beam is preferably annular and the meander line geometry, in certain modifications, is adjusted so that there is a relatively small electric-field variation with radius over the portion of the grid through which the annular beam passes. In a further embodiment, the grid is configured as two interlaced spirals, driven by complementary replicas of the r.f.

Abstract: An electron source includes: linear thermionic cathodes for emitting electron beams; an electron beam lead-out electrode which is disposed substantially in a parallel relationship with the linear thermionic cathodes and is formed with apertures for passing the electron beams therethrough; and a plurality of support members for supporting the linear thermionic cathodes each of which has a contact portion held in contact with at least a portion of the linear thermionic cathodes; wherein each of the apertures of the elctron beam lead-out electrodes is disposed so as to confront the contact portion of the support member.

Abstract: A high-frequency amplifier tube includes a grid that responds to an r.f. input signal to current modulate a linear electron beam derived from a cathode. A resonant structure establishes an electric field in a region between the grid and cathode. First and second resonant cavities downstream of the grid in the named order are coupled to the modulated electron beam. The first cavity responds to the r.f. signal to velocity modulate the current-modulated beam. The second cavity is coupled to the current- and velocity-modulated beam for deriving an output signal. An AC connection from a source of the input signal is established to transformer coupling in the first cavity. A phase-shift circuit adjusts the relative phase of the modulation on the beam as it passes through the first cavity and the phase of the r.f. signal as coupled to the first cavity so that fields induced in the cavity by the modulated beam are optimally phased with respect to fields established in the first cavity by the transformer coupling.

Abstract: The present invention includes a cathode-ray tube (10) capable of providing a high-brightness, high-resolution large screen display that is compatible with, for example, field sequential liquid crystal color display systems and monochrome imaging systems. Preferably, the tube includes a small-diameter cathode assembly (14 of 110) with an adjacent small-diameter control grid electrode (38 or 114). The small diameters of the cathode assembly and the control grid electrode result in relatively little capacitance and are, therefore, compatible with relatively high video signal bandwidths. A thick accelerating electrode (66 or 150) is positioned adjacent the control grid electrode to prefocus the electron beam and, thereby, form it with relatively low spherical aberration. In a preferred embodiment, the electron beam is modulated in a push-pull manner by applying a video modulation signal and its inverse to the cathode and the control grid electrode.

Abstract: To prevent the formation of a corona (2) in a known in-line color picture tube with an automatic-focusing deflection system and four grids (G1-G4), a rectangular opening is provided on the side of the second grid (G2) facing the first grid (G1). As a result, the luminous spot (1) formed by the electron beam at the center of the screen is converted to a vertical ellipse and the ratio of the axes of the lateral ellipses on the edge of the image is reduced, thus improving the sharpness of the edges. The openings (5) in the first grid (G1) are elongated in the in-line direction, in particular rectangular, the adjacent openings of the second grid (G2) are also rectangular and all the other openings in the other grids (G2, G3, G4) are circular. In this way, the ratio of the axes of the luminous elliptical spot (11) produced by the electron beam at the center of the screen is reduced without adversely affecting the sharpness of the edges.

Abstract: A cathode structure for an electron gun of a cathode ray tube contains supporting pieces for preventing the detachment of an insulating block that are buried into insertion grooves made in the insulating block. These supporting pieces contact and are welded to the inside of the skirt of the control grid after they are inserted into the control grid together with the insulating block. This provides high stability against external impacts.

Abstract: A cathode ray tube having an electron gun assembly in which a plurality of electrodes constitute an electron beam generating unit for generating electron beams, and an electron lens unit for focusing the generated beams on a predetermined location on a phosphor screen. The electron gun assembly further contains a pair of insulating support rods for supporting the electrodes, a resistor unit for applying a voltage to at least one of the electrodes. A metal ring is mounted in contact with a predetermined electrode of the electron lens unit and surrounds the insulating support rods. Terminal voltage pickup terminals apply a voltage to the resistor unit. At least a first and second intermediate voltage pickup terminal supply a voltage from the resistor unit to a first and second electrode. The first and second intermediate voltage pickup terminals are located in relation to the metal ring such that a discharge is prevented and image quality is preserved.

Abstract: This cathode has a body made of a material that does not emit electrons, having a substantially smooth non-emissive face and elements made of an emissive material each having an emissive face, spaced out from one another and fixed to the body, for example in hollows with their emissive surface in relief by a determined value with respect to said non-emissive face, so that a protection electrode can be placed between the projecting parts of these elements.

Abstract: A multi-step focusing type electron gun is disclosed which includes a cathode, electrodes G1 and G2, and electrodes G3, G4, G5, G6, G7, and G8 for forming two unipotential auxiliary lenses and a bipotential major lens in the main lens, characterized in that the electrodes G4, G5, G6, G7 are so constituted as to satisfy some specific formulas. The electron gun can reduce the size of the beam spot and the size of the halo formed around the beam spot. Further the electron gun improves the spherical aberration, and provides the flexibility in designing for different purposes, as well as improving the image quality on the screen.

Abstract: A very fine-mesh, non-emissive shadow grid is formed on the smooth emissive surface 16 of a thermionic cathode 12 by deposition from a vapor a continuous layer 22 of non-emissive conductive material. Between the elements 24 of the grid the non-emissive material is removed by bombardment through an apertured mask to restore emissivity between the elevated grid elements 24.