Abstract: An in-line type color Braun tube includes a shield cup electrode which opens at the side facing a fluorescent surface of the tube, provided at the end of an electron gun, wherein the shield cup electrode comprises a cylindrical side wall for shielding three electron beams generated by the electron gun from influences of electrostatic charge accumulated at a wall surface of a glass bulb of the tube, a base plate having three beam passing holes aligned in the horizontal direction, and two cylinders made of non-magnetic and conductive material, for suppressing eddy current induced at the shield cup electrode, each of the two cylinders surrounding one of two paths of electron beams passing through both side holes of the three beam passing holes, projecting from a surface facing the fluorescent surface, of the base, in the direction facing the fluorescent surface.

Abstract: A cathode for an electron tube formed by coating the base of the cathode for the electron tube with an alkaline-earth metal carbonate containing at least barium as the alkaline-earth metal, and thermally decomposing in a vacuum to generate an emitter mainly comprising an alkaline-earth metal oxide, wherein a mixture of two or more kinds of alkaline-earth metal carbonate crystalline particles having different shapes is used as the above mentioned alkaline-earth metal carbonate. Since the present invention can provide a cathode for electron tube having improved both cut-off drift and emission characteristic at the same time, it is useful as a cathode for the electron gun of a CRT, or a cathode for the electron gun of an electron microscope.

Abstract: The present invention provides a cathode-ray tube provided with an electron gun capable of emitting electron beams of vertically elongate cross section.A beam control electrode (G2) is fabricated by forming beam passage holes (22R, 22G, 22B) in thin portions (20R, 20G, 20B) of a reduced thickness of an electrode plate (18), and forming excess metal relieving slots (40R to 45B) on the opposite sides of the beam passage holes (22R, 22G, 22B), respectively. An electron gun employing the beam control electrode (G2) is capable of automatically correcting the cross section of beams so that the beams form substantially circular spots in the periphery of a screen. Thus, the deterioration of picture quality attributable to the distortion of the cross section of the beams can be avoided and pictures can be displayed in an improved picture quality.

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: A cathode ray tube is provided with an electron gun having an electron lens including a large-diameter cylinder electrode and a small-diameter cylinder electrode composed of a large-diameter cylinder portion and a small-diameter cylinder portion, and at least the large-diameter cylinder portion of the small-diameter cylinder electrode is inserted in the large-diameter cylinder electrode thereby forming the electron lens. The small-diameter cylinder portion extending in the tube axis direction of the large-diameter cylinder electrode and connected to the large-diameter cylinder electrode is expanded or bulged, or the bottom portion of the large-diameter cylinder electrode is removed while only the electrode support portion connected to the large-diameter cylinder electrode is left, so that the electrode support fixed to the outer surface of the small-diameter cylinder portion of the small-diameter cylinder electrode can pass therethrough.

Abstract: An in-line electron gun includes an electron beam forming area formed with first and second grids, a main electrostatic focusing lens with first and second accelerating/focusing electrodes, and a shield cup. The first accelerating/focusing electrode is formed in a horizontally elongated rectangular hole and has an elliptical electrode in which electron beam passing holes are formed. The second accelerating/focusing electrode is formed in a horizontally elongated rectangular hole, and the shield cup has a bottom in which non-circular holes are formed.

Abstract: An image display device (1) which includes a cathode ray tube is provided with a cathode system (2) for the emission of a plurality of electron beams (3) whereby a phosphor screen (4) is scanned in order to display an image. The electron beams are modulated on the basis of an electronic image signal by means of a cathode modulator (5). The cathode modulator is arranged to scan different image lines simultaneously by means of separate electron beams. For example, the cathode modulator comprises an extension system (7) and a delay system (8) for deriving extended and delayed extended image line sections from image line sections of the electronic image signal. The cathode modulator also comprises a combination unit (9) for simultaneously supplying an extended image line section and a delayed image line section with which separate electron beams are modulated.

Abstract: A cathode ray tube package includes a cathode ray tube assembly and a housing assembly including a deflection coil and/or at least one focus coil. The cathode ray tube assembly includes a collar (31) aligned with the electron beam, being arranged to mate with a mounting collar (41) carried on the housing assembly. The provision of the collar (31) enables the cathode ray tube assembly to be easily replaced at the end of the cathode ray tube's life within the housing assembly without the need for realignment of the coils.

Abstract: The present invention provides luminescent screens with a mask layer, methods of manufacturing the screens, and display devices incorporating the screens. The mask layer is attached to a matrix defining the pixels in the screen and preferably includes voids formed therethrough corresponding to each pixel. The voids in the mask layer preferably have a size generally corresponding to that of the pixels near the phosphor material and narrow in the direction of the electron source.

Abstract: The centering cup of an in-line electron gun of a color cathode ray tube is provided with four slits, positioned substantially mirror-symmetrical with respect to the in-line plane and with respect to a plane perpendicular to the in-line plane through the central aperture, a line drawn through two slits and the central opening making an angle with the in-line plane ranging between 51 and 63 degrees. The slits reduce the occurrence of eddy currents, without introducing convergence errors.

Abstract: An image display apparatus in which luminance contrast is produced by the act of scanning of electron beams is disclosed. The apparatus of this invention includes: a screen including a plurality of picture elements each having a plurality of miniature luminescent units which respectively exhibit luminescence in response to the application of a plurality of electron beams, the picture elements being arranged in lines and columns; electron-beam generating means for generating the plurality of electron beams which respectively define the plurality of miniature luminescent units in each of the picture elements; control means for controlling emission of the plurality of electron beams so that the number of the miniature luminescent units which exhibit luminance in each of the picture elements may be controlled in accordance with a video signal; and/or means for controlling emission the period of time available for the emission of at least one of the plurality of electron beams.

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 cathode ray tube suitable for use as a visual display includes two or more electron guns. The beams from the electron guns are aligned vertically so that a single horizontal scan of the guns produces two rows of pixels on the front face of the tube. This allows twice as much data to be painted on the display screen without increasing the scan rate of the electron guns. Each of the guns may be a single beam gun, for monochrome displays, or each may be a triple-element gun for RGB displays.

Abstract: A color cathode-ray tube has an in-line type electron gun. Third, fourth, and fifth electrodes form a sub-main lens, and a sixth electrode forms a main lens with the fifth electrode for focusing the three electron beams onto the phosphor screen. The second and fourth electrodes are electrically connected together and the third and fifth electrodes are electrically connected together. A ratio A of an axial length of the fourth G4 electrode to a diameter of the opening of the fourth electrode and a ratio B of an axial length of the fifth G5 electrode to the diameter of the opening of fourth electrode satisfy the following equations: 54A-5B+4.ltoreq.0, 55A-5B+7.gtoreq.0, A-0.18.gtoreq.0, and 95A+10B-73.gtoreq.0.

Abstract: An electron gun body for a color cathode ray tube includes an electron beam forming region formed by cathodes, first and second grids, and a main focusing lens having first and second accelerating and focusing electrodes for substantially focusing three electron beams from the electron beam forming region.

Abstract: A color cathode ray tube equipped with an in-line electron gun includes a main lens made up of two cylindrical electrodes arranged in a spaced relationship. Each of the electrodes has an opening and having therein a plate electrode with a beam passing area. The electrodes are given different voltages, wherein the D and S values are in the region where all of the following inequalities are satisfied;5.0>S,D>S, and55S-20D.gtoreq.145.5S being a beam spacing between central axes of adjacent electron beams, and D being a diameter in a direction perpendicular to an in-line arrangement of the electron beams, of the cross section of an opening at opposing ends of the electrodes.

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. In the beam-forming region of the electron gun, a charged grid includes an array of apertures including at least upper and lower horizontally aligned apertures for passing inline arrays of beams.

Abstract: In an electron gun for a CRT in which a plurality of cylindrical electrodes are arranged and fixed in series to control a path of electron beams emitted from a cathode, a cylindrical support member is disposed between at least two adjacent cylindrical electrodes so that the two cylindrical electrodes are arranged coaxially. One end portion of the cylindrical support member and one cylindrical electrode are fixed to each other by fitting the former into the latter or vice versa, and the other end portion of the cylindrical support member and the other cylindrical electrode are fixed to each other by fitting the former into the latter or vice versa.

Abstract: A cathode, an electron gun, and a cathode-ray tube, having a configuration wherein a heat source for heating an electron emission portion in which an electric field is applied to the tip so that electrons are pulled out is disposed, whereby instability and reduction in amount of emitted electron rays which are due to an effect of adsorbed gas molecules can be prevented from occurring.

Abstract: An electron gun for the cathode-ray tube is disclosed, in which an early stage lens unit and a main lens unit are respectively constructed as a bipotential form lens. A high voltage equivalent to the voltage applied to a grid of the main lens unit is applied to a grid of the early stage lens unit thereby to reduce the space charge effect, while at the same time suppressing the change of the beam spot shape with the change in the beam current.

Abstract: A low-power cathode can be obtained by arranging it on a substrate (1), preferably of silicon, which is entirely or partly removed at the location of the emissive structure (11) by means of, for example, anisotropic etching. Because of its low power, the cathode is particularly suitable for multi-beam applications.

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: A multi-beam electron gun for use in a monochrome cathode ray tube (CRT) such as used in a black and white television receiver, a projection television receiver, or a computer monitor includes G1 control and G2 screen grids each having a plurality of vertically aligned apertures for forming electron beams which are deflected in unison across the CRT's display screen to simultaneously trace a plurality of vertically spaced, horizontal scan lines with each display screen sweep. The electron beams are deflected across the screen in a raster-like manner with each beam containing video information for each adjacent scan line. The G1 control grid includes a plurality of discrete conductive portions each including a respective beam passing aperture and each coupled to a respective video signal source, with the video signal sources including memory for storing video signal information for subsequent display.

Abstract: An inline electron gun for a color cathode ray tube (CRT) directs electron beams through an Einzel lens common to all of the beams for focusing the beams on a display screen across which the beams are scanned in horizontal scan lines in a raster-like manner. The electron gun includes a beam forming region (BFR) for forming the beams in a matrix array including a plurality of vertically spaced, horizontally aligned apertures, where each horizontally aligned group of apertures passes the primary color electron beams for one scan line on the display screen and vertically aligned apertures are grouped to pass common color electron beams which are horizontally deflected in synchronism over adjacent, vertically spaced scan lines on the display screen.

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: An electron gun for a color picture cathode-ray tube which includes a main focusing lens of a large diameter for reducing deterioration of the focusing property caused by the spherical aberration of the main focusing lens, shortening the distances among three electron beams to minimize the deflection aberration from deflection yoke and making feasible a design for effective enlargement of the lens diameter even with the shortening of the distances among the three electron beams in the color picture cathode-ray tube requiring a good focusing property of the three beams.

Abstract: A novel electron gun for the color picture tube is disclosed, which comprises at least a cathode for emitting three electron beams in alignment and focusing electrodes for focusing the electron beams emitted from the cathode. The forcusing electrodes include first and second focusing electrodes for passing electron beams. The first focusing electrode includes a plurality of perpendicular plate electrodes arranged in such a manner as to sandwich the electron beams along the direction of arrangement thereof after being passed through the passage apertures and rim electrodes surrounding the perpendicular plate electrodes. The second focusing electrode includes a couple of horizontal plate electrodes arranged in such a manner as to hold the electron beams along the direction perpendicular to the direction of arrangement thereof after being passed through passage apertures and extending in opposed relationship with the perpendicular plate electrodes and rim electrodes along tht electron gun axis.

Abstract: The in-line type electron gun of this invention is formed so that a depression, which is formed at the lower voltage electrode face opposing to the higher electrode of the two electrodes for forming a common main focusing lens in the opposing gap thereof and has three lens holes for individual electron beams arrayed in-line at the bottom thereof, is formed so that the width in the direction perpendicular to the lens hole array direction is smaller at the central part in the lens hole array direction as compared with the other parts. Also the center lens hole of the three lens holes at the bottom of the depression is smaller in diameter than the other two. Accordingly, the focus voltages of the three beams passing through the three lens holes and the shapes of beam spots are made more uniform as compared with the prior art.

Abstract: A three-beam unitized, in-line electron gun for a color cathode ray tube has a series of hollow, rectangulr-in-cross-section electrodes for the side-by-side accommodation of the three beams. A two-element anode electrode for the gun includes first and second cup-shaped elements each having an apertured electrode face. The second cup-shaped element is nested in the first element, and has a cup draw effective to provide a predetermined distance between the electrode faces when the cups are in nested relationship. The critical focusing and convergence of the gun can thereby be adjusted by the adjustment of the cup draw.

Abstract: An in-line type color CRT electron gun having a triode and a plurality of grids, characterized in that at least one of the plurality of grids is made of a black member or a member on which a black film is formed. The time required for attaining a stable temperature of the member is reduced, thereby improving deviations in static convergence and reducing the time required for an image to be normally displayed.

Abstract: The stability of semiconductor cathodes is improved by reducing the effective emitting surface area. This is effected by producing emission patterns by means of separate emission regions, whose overall surface area is much smaller than that of the actual emission patter. Due to the higher emission current and adjustment current, adsorbed particles, which adversely affect the stability of the emission, are rapidly drained.

Abstract: A cathode ray tube is disclosed which has a modulating grid for varying the charged particle flux density along a cross-section of a flat thin of charged particles or for varying the charged particle flux density in each of a plurality of charged particle beams arranged side-by-side in a sheaf. In a preferred embodiment, a cathode ray tube according to the invention includes a modulating grid and associated electronics that permit the tube to project a single line of video information simultaneously, thus increasing picture brightness. The beam scan is solely vertical, rather than horizontal and vertical, as in cathode ray tubes of the prior art.

Abstract: In a color picture tube with an in-line gun system elliptic beam-spot distortion caused by the deflection field is compensated for by pairs of plates in at least one focus electrode. The plates project into the apertures for the electron beams and are located at a distance from the bottom of the focus electrode.

Abstract: A color cathode ray tube with a shadow mask has a screen partitioned into a plurality of elemental screen areas and electron guns positioned and corresponding to the respecting elemental screen areas, the electron guns generating electron beams to scan the screen. The shadow mask includes effective regions having a number of apertures passed through by the electron beams to impinge on the screen and a non-effective region adjacent to the effective regions. Phosphors as a signal source are deposited on the non-effective regions or the boundaries between the elemental screen areas to emit a light signal by electron beam excitation. A photo-electric transducer is provided facing the shadow mask and to detect the light signal for feed back to a deflection system to control the electron beam deflection.

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: Coma correction means is provided in a color display tube including an evacuated envelope (1) containing an electron gun system (5) of the "in-line" type to generate three electron beams (6, 7, 8) situated with their axes in one plane. The electron beams converge on a display screen (10) provided on a wall of the envelope and are deflected over the display screen in two mutually perpendicular directions by means of a first and a second deflection field. The first deflection field is parallel to the plane. The electron gun system includes at its end field shapers (34, 35) for causing the frames described on the display screen by the electron beams to substantially coincide the field shapers include substantially annular elements (34) of a material having a high magnetic permeability around the two outermost beams. Two elongate flat strips (35) of a material having a high magnetic permeability are provided symmetrically with respect to the axis (37) of the central beam and the plane through the beam axes.

Abstract: The efficiency of a semiconductor cathode can be increased by bombarding the electron-emitting regions (8) with an electron beam (8), which frees the surface from adhered oxygen particles. The electron beam preferably originates from a second semiconductor cathode (42), which has an opening (42) for passing the electron beam (20) of the first semiconductor cathode (20). Alternatively, both semiconductor cathodes can be realized in one semiconductor body.

Abstract: In an in-line type color picture tube device, a deflection yoke is arranged around the neck and funnel sections and the deflection yoke comprises saddle coils for generating a horizontal deflection magnetic field and troidal coil for generating a vertical deflection magnetic field. First and second annular magnetic field control elements of a magnetic material with a high permeability are located between the deflection yoke and the cathodes of an electron gun assembly to surround the beam paths of center and side beams emitted from the cathodes. The second element is arranged closer to the cathode than the first elements.

Abstract: The novel CRT includes a color-selection structure which comprises a first electrode having a plurality of column and row elements forming a plurality of apertures, and a second electrode including an array of conductors electrically insulated from the first electrode. The plurality of apertures in the first electrode comprise alternate columns of first and second apertures. The first apertures have a width less than the width of the second apertures which are intersected by the conductors of the second electrodes to form first and second windows. The CRT also includes a viewing screen comprising an array of substantially parallel phosphor stripes of three different emission colors arranged in cyclic order in adjacent triads. Each of the triads of phosphor stripes is associated with a column of first and second windows and a column of first apertures.

Abstract: An improved color picture tube has an inline electron gun for generating and directing three electron beams, comprising a center beam and two outer beams, along coplanar paths toward a screen of the tube. The three beams pass through a deflection zone adapted to have vertical and horizontal magnetic deflection fields established therein. The improvement comprises the inclusion of means for nonlinearly increasing the effect of the vertical magnetic deflection field on the center beam relative to the outer beams with increasing angles of vertical deflection of the beams.

Abstract: A flat cathode-ray tube wherein a horizontally uniform sheet-like electron beam is vertically deflected and modulated with a video signal, with the modulated electron beam irradiating a portion of a phosphor screen, includes a modulation electrode assembly arranged by n electrode groups, each consisting of at least one first electrode group and at least one second electrode group, the first electrode group having vertically elongated stripe electrodes, each having one or n (n is an integer of 2 or more) openings or slits corresponding to each pel and which are aligned in the horizontal direction on at least one plane such that all openings are equidistantly formed, the second electrode group having the same construction as the first electrode group or being arranged such that vertically elongated stripe electrodes, each having n openings or slits corresponding to n pels along the horizontal direction are aligned on at least one plane to equidistantly form the openings along the horizontal direction, all the o

Abstract: A cathode ray tube comprising in an evacuated envelope (1) an electron gun system (5,104) for generating at least one electron beam (6,7,8,105) which is focused on a target (10,108) by means of at least one accelerating electron lens (22,23,50,51). The lens viewed in the direction of propagation of the electron beam, comprises a first (22,50) and a second (23,51) electrode separated by a lens gap (30,53). In the second electrode is an electrically conductive foil or gauze (31,52) intersects the beam at a distance from the lens gap. When the foil or gauze is flat and is provided at such a location that 0.25<l/R<2.0, where l is the distance from the foil or gauze to the lens gap and R is the radius of the part of the second electrode in which or against which the foil or gauze is provided. The spherical aberration in the electron beam is drastically reduced. Such a flat gauze moreover is easy to manufacture and assemble in an electron gun.

Abstract: A multicolor cathode-ray tube for use as a light source in a giant display system such as a display board for a sports stadium. The cathode-ray tube includes a plurality of electron guns and respective fluorescent screens, the latter receiving the beam from a corresponding electron gun. Each of the screens is slanted towards the longitudinal axis of the tube. The screens may be either flat or curved.

Abstract: There is provided a flat cathode ray tube, wherein a plurality of individual thermionic emission cathodes symmetrically arranged at a predetermined equal spacing on a plane parallel to an image display plate, the same plurality of grids, and fluorescent anode portions which emit light by irradiation with the electrons incident therein, are inserted and sealed in a high vacuum envelope whose image display plate is transparent. For use in a color television system, the cathode ray tube further includes a system for deflecting the individual beams to appropriate color spots in the anode. There is further provided a method for manufacturing a thin television picture tube using photolithographic techniques which make possible a tube which is between 1 and 30 millimeters in thickness with the picture area of a conventional tube.

Abstract: An electron gun assembly includes a plurality of cathode assemblies and a plurality of spaced successive electrodes mounted on at least two electrically-insulative support rods. At least one of the electrodes comprises a deep-drawn substantially rectangular cup-shaped member having a base portion, a supporting flange portion, including a plurality of attachment tabs, and a sidewall extending therebetween. The sidewall includes a plurality of reinforcing ribs formed therein which extend substantially from the supporting flange portion to the opposite end of the sidewall adjacent to the base. The reinforcing ribs minimize the flexure of the sidewall.

Abstract: The invention relates to incorporating improved beam shielding means into the unitized focusing electrode structure of a plural beam in-line color cathode ray tube electron gun assembly. At least a portion of the G3 electrode structure is fabricated of a magnetic alloy material. Positioned forward and adjacent to the magnetic portion is an apertured planar shielding means also fabricated of magnetic material. The cooperation of these adjoining magnetic areas provides significant shielding of the beams from the deleterious back-field of the deflection yoke.

Abstract: An inline electron gun, for use in a cathode-ray tube, comprises four electrode means. The first electrode means forms three inline electron beams including a center beam and two outer beams. The second electrode means pre-focuses each of the electron beams individually and converges the two outer beams toward the center beam to cross-over each other within the electron gun. The third electrode means provides a common main focus lens for the three electron beams at the crossover of the beams. And, the fourth electrode means provides a common post-focusing lens for the three electron beams which causes the two outer beams to converge with the center beam near a screen of the tube.

Abstract: An electrode structure for an electron gun, especially an in-line type electrode structure for an electron gun of a color picture tube. The electrode structure dispenses with auxiliary electrodes and its three cylindrical members are integrally formed by press work. After the pressing step, the inner edge of the bottom portion of each cylindrical members is beveled to provide a tapering surface having a desired circular cross section. By forming a circular groove in the bottom portion, opposite to the tapering surface, the formation of the tapering surface is made more exact.

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: An encapsulated planar cathode structure is formed for a vacuum tube. A multibeam cathode ray tube is obtained by heating in the CRT such a structure with a plurality of separated electron emissive layers to remove the encapsulation material. Positive photoresist technology is utilized: for obtaining delineated apertures on a planar metallization layer supported by an insulating substrate into which needle-shaped carbonate particles are deposited electrophoretically normal to the metallization; and for encapsulating the resultant cathodes.