Abstract: The present invention discloses an improved electron gun for a color picture tube including a main lens having a first rim electrode having a beam passing plane with holes in an incident side of the electron beam and a second rim electrode facing the first rim electrode and having a beam passing plane with holes in a departing side of the beam. A focusing electrode having a beam passing plane with holes in departing side of the beam for forming compensating astigmatism quadrupole lenses in conjunction with the first rim electrode to compensate for the astigmatism of the main lens is positioned adjacent to the first rim electrode of the main lens. Astigmatism formed between the first and second rim electrode of the main lens electrodes can be reduced by the compensating astigmatism of the quadrupole lenses.

Abstract: An in-line electron gun for a color cathode ray tube is disclosed including a main focusing electrode and an accelerating electrode common for electron beams and having an elliptical aperture. An auxiliary electrode disposed within each of the main focusing electrode and accelerating electrode and being retreated from rims of the main focusing electrode and accelerating electrode, respectively. In addition, a shield cup is installed adjacent to the accelerating electrode, the shield cup having an aperture that is horizontally longer than vertically.

Abstract: An electron gun for a color cathode ray tube is formed with a control electrode, an accelerating electrode, an anode, and a focusing electrode divided into a first and a second focusing electrode. A static focusing voltage predetermined independently of a deflection period is applied to the first focusing electrode and a parabolic waveform dynamic focusing voltage varying according to the deflection period is applied to the second focusing electrode. The first focusing electrode has three electron beam apertures with vertical parallel plates mounted around each aperture in a direction opposite to the direction of the electron beams. The second focusing electrode has three electron beam apertures with horizontal parallel plates mounted around each aperture in a direction opposite to the direction of the electron beams. The centers of the left and right electron beam apertures are offset to the left and right sides of the central axis of the vertical and horizontal parallel plates.

Abstract: An electron gun for a color cathode ray tube taking a multi-level focusing form includes a focusing electrode and a pre-focusing electrode. The distances between the centers of the apertures of the focusing electrode are larger than the distances between the corresponding apertures of the pre-focusing electrode. The electron gun further includes a post-focusing electrode. The distances between the centers of the apertures of the focusing electrode are larger than those of the corresponding apertures of the post-focusing electrode. But, the center distances between the apertures of the pre-focusing electrode are equal to the center distances between the corresponding apertures of the post-focusing electrode. The post-focusing electrode is partitioned from the focusing electrode.

Abstract: A display device with a DAF-gun (Dynamic Astigmatism and Focusing) in which the first focusing electrode (G3a) has at the side facing the pre-focusing part of the electron gun three elongated apertures (36, 37, 38). Hereby in operation in the vicinity of the elongated apertures an electron-optical field is generated between the pre-focusing part of the electron gun and the elongated apertures for reduction of the vertical dimension (vertical meaning transverse to the plane of the electron beams) of the beam size of the electron beams in the main lens. This reduction of the electron beam size results in an increase of the vertical dimension of the beam spot on the screen. This reduces Moire effects.

Abstract: In a color picture tube having a wide and flat screen, one set of in-line three electron beam through holes on an end face of a first focusing electrode facing a second focusing electrode are formed with a vertically oblong rectangular shape, and the other set of in-line three electron beam through holes on an end face of the second focusing electrode facing the first focusing electrode are formed with a horizontally oblong rectangular shape, a pair of protrusions is provided on a pair of longer sides of each of the electron beam through holes. Therefore, intensive quadrupole fields, by which deflection distortion can be cancelled, can be generated. Fluctuation of the quadrupole fields due to interference of a dynamic voltage and focusing voltage, which are to be applied to the focusing electrodes, can be prevented.

Abstract: A color cathode ray tube includes a final lens, a multipole lens and a lens for correction of curvature of the image field. The final lens focuses more horizontally and its strength weakens in accordance with an angle of beam deflection. The strength of the multipole lens for elongating a cross section of electron beams horizontally weakens in accordance with an angle of beam deflection. The lens for correction of curvature of the image field weakens in accordance with an angle of beam deflection.

Abstract: A double cross-over type electron gun for a color CRT is provided. The electron gun includes a triode having a cathode, a control electrode and a screen electrode, for generating and controlling an electron beam, a plurality of focus electrodes sequentially disposed adjacent to the triode, for forming at least one auxiliary lens, and a final accelerating electrode disposed adjacent to the focus electrode, for forming a main lens. The electron beam generated by the triode includes a cross-over point in front of the main lens and proximate to the auxiliary lens. At least one of the auxiliary lenses disposed upstream from the main lens is formed as a quadrupole lens so that the position of the cross-over point in the horizontal direction and that in the vertical direction are different from each other. When a dynamic focusing voltage is applied, the image quality at the periphery of a screen can be greatly improved.

Abstract: A color cathode ray tube which has its resolution improved all over its screen covering the central portion and the peripheral portion, either by elongating or narrowing the plate length of plate electrodes 243, which are formed between a first kind of focusing electrode 241 and a second kind of focusing electrode 242 constituting together the electrostatic quadrupole lens of a halved focusing electrode 24 and which are connected with the second kind of focusing electrode 242, at the vertical portion 2430 of a passage for a central electron beam, or by making the shape of the central electron beam passing hole of an electrode 245 formed with the electron beam passing holes of the first kind focusing electrode 241, longer than the shape of the electron beam passing holes for the side electron beams.

Abstract: A color cathode ray tube comprising in-line electron gun producing three electron beams, said electron gun having main lens comprising two cylindrical electrodes arranged in a spaced relationship in a direction of an axis of said tube, said two cylindrical electrodes being given different voltages, wherein the following inequalities are satisfied,2S+13.66.ltoreq.T.ltoreq.28.14.1.ltoreq.S,S being a beam spacing in mm between central axes of said three adjacent electron beams at said main lens, and T being an outside diameter in mm of a neck portion of a vacuum envelope housing said in-line electron gun.

Abstract: In a color cathode ray tube having an inline electron gun, an electrode geometry asymmetric in the inline direction is provided on the two side beam apertures in the first grid electrode for the two side beams on the side facing the cathode such that as the electron beam current through the side beam apertures decreases, the degree of an asymmetry in the inline direction in a distribution of an electric field between the side beam apertures and the cathodes increases.

Abstract: A colour display tube has an in-line electron gun for generating three co-planar electron beams first and second lens electrode produce a focusing lens field for focusing the electron beams. At least one of the lens electrodes has a correction element for tuning the astigmatism of the lens field. The correction element includes three co-linear apertures for passing the electron beams, the outer apertures of which are funnel-shaped, the wide end of the funnel-shape being directed away from the center aperture.

Abstract: A color cathode ray tube has an evacuated envelope including a panel portion having a phosphor screen and a neck portion, and an in-line electron gun including a main lens and an electrostatic quadrupole lens and housed in the neck portion. The focus electrode of the main lens has a single opening at its one end for the three electron beams. The single opening has a diameter larger in a horizontal direction than that in a vertical direction. A distance from the main lens to the phosphor screen is not larger than 300 mm, an outer diameter T of the neck portion satisfies the following inequality: 23.2 mm.ltoreq.T.ltoreq.25.9 mm, and a value D of twice a distance from the side electron beams to a vertical edge of the single opening satisfies the following inequality: 5.0 mm.ltoreq.D.ltoreq.6.5 mm.

Abstract: A phosphor screen comprising three color phosphor layers that emit red, green, and blue light is provided on the inner surface of a panel of an envelope, and an in-line type electron gun assembly for emitting three electron beams aligned on the same axis (generally a horizontal axis X) is mounted in a neck. This electron gun assembly has three cathodes arranged in a row, and a plurality of electrodes for sequentially focusing and accelerating the electron beams from the respective cathodes toward the phosphor screen. A pair of belt-like magnetic segments are provided on the outer wall of the neck of the envelope to serve as magnetic members for adjusting an external magnetic field. Each magnetic segment is made of a hot-rolled silicon steel plate having a thickness of 0.35 mm, a width of 4 mm, and a length of 40 mm in the direction of the tube axis.

Abstract: A color cathode ray tube equipped with an in-line electron gun emitting three electron beams includes a main lens made up of two cylindrical electrodes arranged in a spaced relationship. Each of the electrodes has an opening of an elliptic cross section and therein a plate electrode with a beam passing area, and is given different voltages. The following inequalities apply:5.0>S, D>S, and 55S-20D.gtoreq.145.5,S is a beam spacing between adjacent electron beams, and D is the smaller dimension of either a diameter in a direction perpendicular to the in-line arrangement of three electron beams of the cross section of the opposing ends of the two cylindrical electrodes or twice the distance between a center of a side electron beam and an inner edge in a direction of the in-line arrangement of the three electron beams of the cross section of the opposing edge of the two cylindrical electrodes.

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 electron gun for a cathode ray tube includes a triode composed of a cathode, a controlling electrode, and a screen electrode. A pre-focusing electrode is provided and supplied with a first voltage for pre-focusing electron beams emitted from the triode. A first auxiliary electrode is provided and supplied with a second voltage which is also supplied to the screen electrode. A second auxiliary electrode is provided and supplied with a third voltage which is also applied to the controlling electrode. The applied voltages create divergent lenses between the focusing electrode and the first auxiliary electrode and between the first and second auxiliary electrode. A main focusing electrode is provided and supplied with the first voltage like the pre-focusing electrode. A converging lens is formed between the second auxiliary electrode and the main lens. A final accelerating electrode is installed adjacent to the main focusing electrode and supplied with a fourth voltage.

Abstract: The present invention provides an electron gun assembly including at least one field emission type cold cathode acting as an electron beam source, a support for supporting the cold cathode thereon, a control electrode spaced away from the cold cathode, the control electrode cooperating with the support to enclose the cold cathode therein, a thermal shield member provided both around the control electrode and below the support to prevent heat conduction to the cold cathode. The thermal shield member does not allow heat conduction to the cold cathode when the electron gun assembly is to be enclosed in a glass valve by softening a neck portion of the glass valve with an oxygen burner and then attaching the softened neck portion to the electron gun assembly, resulting in that an emitter of the cold cathode is not increased in temperature and that a summit of an emitter is not oxidized.

Abstract: In a color cathode ray tube apparatus, a main electron lens unit for converging three in-line electron beams on a phosphor screen is formed of a plurality of electrodes, including at least first, second, and third electrodes, which are arranged from the cathode side toward the phosphor screen. An asymmetric electron lens, which horizontally diverges and vertically converges the electron beams, is formed on the cathode side in a lens effect region of a first electron lens composed of the second and third electrodes, and an asymmetric second electron lens, which has one effect with respect to the horizontal direction of the electron beams and another with respect to the vertical direction, is formed between the first and second electrodes, at the least.

Abstract: An electron gun which has an assembly precision improved by the reduction of deformation of an electrode during assembly as well as good focusing performance due to the elimination of positional deviation of electron beams. The electron gun comprises a composite electrode including at least two electrode elements united together and a plurality of electrodes sequentially arrayed along a single axis at predetermined intervals. In the electron gun, opposed faces of the electrode elements of the composite electrode are perpendicular to the axis and the opposed faces are provided with projections which serve to constitute the composite electrode when the projections are united together in opposed relationship to each other.

Abstract: A color-picture tube having a convergence electrode, to which a focusing voltage is applied, a final accelerating electrode, to which an anode voltage is applied, and at least one supplementary electrode placed between the convergence electrode and the final accelerating electrode, to which either (1) a voltage higher than the focusing voltage and lower than the anode voltage is applied or (2) no voltage is applied, resulting in the supplementary electrode being free from a directly applied electric potential, wherein its electric potential is induced by the convergence electrode and the final accelerating electrode. Each of the convergence electrode and the final accelerating electrode is a tube having an elliptical cross section closed with an elliptical end plate having three holes arranged in-line for electron passage. In at least one of the tubes, the end plate is positioned away from the opening of the tube closer to the supplementary electrode.

Abstract: An electron gun having at least one tube, a pair of holders for holding both ends of the tube, a plurality of electrode layers which are provided on the inner surface of the tube so as to form a part of a main lens, at least one conductive layer provided on the surface of the tube, and a plurality of electrodes for forming a part of triode. Also, a method of manufacturing an electron gun comprises the steps of forming a plurality of electrode layers on the inner surface of at least one tube, providing at least one conductive layer on the surface of the tube, providing a pair of holders so as to hold both ends of said tube, providing a voltage supplying device on one of the pair of holders, and welding a plurality of electrodes forming a part of a triode to the other of the pair of holders.

Abstract: A color cathode ray tube apparatus is provided with an electron gun assembly. In the electron gun assembly, three electron beams, which are emitted from cathodes of an in-line arrangement, are accelerated and converged onto a phosphor screen by an electron lens system of the electron gun assembly. The electron lens system is constituted by a plurality of grid electrodes and includes individual electron lenses and a common electron lens. Each of the individual electron lenses has first and second lens powers in horizontal and vertical planes, respectively. Each of the electron beams is diverged in the horizontal plane and converged in the vertical plane by the corresponding individual electron lens due to the first and second lens powers. The common electron lens has third and forth lens powers in the horizontal and vertical planes, respectively.

Abstract: A main lens member for an electron gun comprises at least one high electrical resistance layer formed of a higher electrical resistance material sandwiched between low electrical layers which are laminated together to form a main line of an electron gun.

Abstract: An electron gun of a color picture tube which can make uniform beam spots on a screen by eliminating astigmation of electron beams caused by a self-convergence yoke is constructed by the use of the improved shapes of vertical blades or horizontal blades of astigmation correction electrodes.

Abstract: The focusing characteristic of this electron gun is not impaired by the aberration caused by the deviation from the centers of the holes on both sides of the main lens, through which the electron beams pass, and the astigmatism of the electron beams due to the uneven magnetic field such of a deflecting yoke when the electron gun is in operation. In the focusing electrode 1 of the electron gun a assembly, a plurality of focusing grooves are formed parallel to the direction in which the electron beams pass. A plurality of additional electrode members, each consisting of a flat thin plate, are inserted into the focusing grooves, respectively.

Abstract: An electron gun for a color picture tube which allows the foci of electron beams to coincide with one another. Making an eccentricity between beam-passing apertures and holes on partitions, the electron gun reinforces an electron lens effect, so that the foci of electron beams can coincide with one another.

Abstract: An electron-beam gun system is provided having a cathode arrangement and a grid electrode. The cathode arrangement is a high-current cathode (22) having an emitting surface (23). The grid electrode includes a hat-shaped grid 1-electrode (24) located at a distance of 30 to 80 .mu.m from the emitting surface (23) of the high-current cathode (22), which has a width in a range of 30 to 70 .mu.m in a passing area (18.2) for electrons. The grid electrode includes a grid 2-electrode (15) that is at least 250 .mu.m wide in a passing area (18) for the electrons, and includes a grid 3-electrode (14) having an inlet side that is 250 to 400 .mu.m wide in a passing area (18.1) for the electrons.

Abstract: In a conventional construction of an electron gun with quadrupole lenses, a grid part with elongated apertures all arranged in the same direction cannot be easily secured to alignment mandrels of circular cross section. As a result, grid movement during assembly can cause a misalignment that deteriorates the tube resolution. The present invention includes arranging circular and elongated apertures in the same grid part, and also alternately arranging circular and elongated apertures in adjacent grid parts, so as to secure the grid parts to the mandrels and automatically maintain the alignment during gun assembly. The aperture combinations described herein produce electron lens astigmatism of approximately the same strength and sign for each beam of an in-line gun.

Abstract: In a color cathode ray tube apparatus having an electron gun assembly for emitting three electron beams disposed in one line, the electron gun assembly has at least first, second, and third electrodes G5, G7, and G9 applied with a voltage which changes in synchronization with deflection of electron beams. The first electrode and an electrode G4 adjacent thereto form first eccentric lenses for deflecting a pair of side beams in a direction in which the side beams extend to be close to the center beam. The second electrode and an electrode G6 adjacent thereto form second eccentric lenses for deflecting the side beams in a direction in which the side beams extend to be apart from the center beam. The third electrode and an electrode G8 adjacent thereto form third eccentric lenses for deflecting the side beams in a direction in which the side beams extend to be close to the center beam. An electron lens common to the three electron beams is formed between the second and third eccentric lenses.

Abstract: An electron gun for use in a cathode ray tube (CRT) includes a cathode, a low voltage beam forming region (BFR), and a high voltage deflection focus lens disposed in the beam deflection region of the CRT's magnetic deflection yoke for simultaneous and coincident focusing and deflection of the electron beam on the CRT's display screen. The deflection lens includes a plurality of first focus grids disposed in the CRT's neck portion including a spaced first pair of grids (G42, G44) having respective beam passing apertures disposed horizontally off-center in opposed directions relative to the electron beam axis, and a second pair of grids (G46, G48) having respective beam passing apertures disposed vertically off-center in opposed directions relative to the axis. Other grids disposed on opposed sides of each of the first and second pair of grids have respective beam passing apertures centered with respect to the electron beam axis and are maintained at a fixed focus voltage.

Abstract: A color cathode ray tube includes a final lens, a multipole lens and a lens for correction of curvature of the image field. The final lens focuses more horizontally and its strength weakens in accordance with an angle of beam deflection. The strength of the multipole lens for elongating a cross section of electron beams horizontally weakens in accordance with an angle of beam deflection. The lens for correction of curvature of the image field weakens in accordance with an angle of beam deflection.

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 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: 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: There is provided an electron gun which has an assembly precision improved by the reduction of deformation of an electrode during assembly as well as good focusing performance due to the elimination of positional deviation of electron beams. There is also provided a method of assembling such an electron gun. The electron gun comprises a composite electrode including at least two electrode elements united together and a plurality of electrodes sequentially arrayed along a single axis at predetermined intervals. In the electron gun, opposed faces of the electrode elements of the composite electrode are perpendicular to the axis and the opposed faces are provided with projections 1a and 1b which serve to constitute the composite electrode when the projections are united together in opposed relationship to each other.

Abstract: An electron gun for a color cathode ray tube is disclosed in which a correction electrode having horizontally elongated electron beam passing holes is fixed in a second accelerating/focusing electrode located between an inner shield fixed to the second accelerating/focusing electrode and a shield cup, thereby correcting astigmatism of an electron beam.

Abstract: The present is directed to a cathode ray tube having compensation plates for compensating the misconvergence of the paths of the beams of the tube resulting from the earth's magnetic fields, The cathode ray tube includes a neck portion and a funnel portion with a face plate, A gun is in the neck portion and is adapted to generate three electron beams and direct the beams toward the face plate. Purity convergence magnets are around the tube adjacent the neck, The compensation plates are between the purity convergence magnets and the tube and extend in parallel relation to the beam paths at opposite sides of the beams.

Abstract: An electron gun for a color cathode-ray tube, adapted for large television sets or high-definition monitors, has first and second quadrupole electrodes connected to a static voltage focus electrode and to a dynamic voltage focus electrode, respectively, to form a quadrupole lens. The first quadrupole electrode is composed of first electrode pieces connected to the static voltage focus electrode and arranged on left and right sides of three beam-passing apertures formed on the static voltage focus electrode, and each of the first electrode pieces has at least one arc having a radius identical to or larger than that of the beam-passing apertures. The second quadrupole electrode is composed of second electrode pieces connected to upper and lower portions of the dynamic voltage focus electrode, and each of the second electrode pieces has arcs having a radius identical or larger than that of the beam-passing apertures. The first electrode pieces are inserted inside of the second electrode pieces.

Abstract: In a color cathode ray tube apparatus including an electron gun assembly having a main electron lens section for focusing and converging three electron beams arranged in a line on a phosphor screen, three electron beam through holes arranged in a line in the arrangement direction of the three electron beams are formed in each of the opposing surfaces of the first electrode having a relatively low potential and a second electrode having a relatively high potential, which electrodes constitute the main electron lens and substantially oppose, the pair of side beam through holes of the second electrode are decentered outward in the arrangement direction of the three electron beams with respect to the pair of side beam through holes of the first electrode, and each of the pair of side beam through holes of any one of the first and second electrodes is formed to have a substantially horizontally elongated shape in which both sides in the arrangement direction of the three electron beams are constituted by arcs and

Abstract: In-line electron guns for color picture tube improving the resolution of the color picture tube. The guns not only exhibit the special quality of a large aperture of lens but also achieve the desired mechanical strength of electrodes by arranging .OR right.-shaped inner electrode plates in the envelope electrodes respectively. Each of first and second accelerating/focusing electrodes for focusing three electron beams of the electron beam sources on the phosphor screen includes an envelope electrode and an electrostatic field control electrode placed in the envelope electrode. The envelope electrode includes a predetermined length of hollow envelope part and a predetermined width of rim part extending from an edge of the hollow envelope part. The electrostatic field control electrode includes a plate electrode sided by predetermined width of blades at opposed sides thereof. This blade sided plate electrode is holed at its center so as to have a center beam passing opening.

Abstract: An electron gun for a color cathode-ray tube for providing a passage for a plurality of electron beams, each beam representing a color component for forming a color image. The electron gun of the present invention includes a pair of electrodes substantially symmetrical to one another with respect to the horizontal direction and coaxial with the tube in the axial direction. Each electrode has a common opening. Each common opening faces the other and is spaced from the other at a given distance in the axial direction. According to an embodiment of the present invention, each electrode includes first and second electrode member. The first electrode member inside the electrode is spaced at a given distance from the common opening of the electrode in the axial direction. The first electrode member includes a plurality of openings in cascade in the horizontal direction, and these openings partially overlap one another and communicate to one another collectively to form a singly aperture.

Abstract: A cathode ray tube comprising a cathode (K) for emitting a beam of electrons; a grid (G) for controlling the intensity of the beam; three or more anodes (A1, A3, A4); a control for varying the potential of at least one of the anodes (A3) for focusing the beam to form a spot on a screen; and an additional, dynamic focus electrode (A2) maintained generally at a potential close to the cathode/grid potential. Suitable structure may be included for applying to said dynamic focus electrode a high frequency signal to provide a rapid focus control. Said dynamic focus electrode may comprise a plurality of circumferentially disposed segments and including applying a separate high voltage to each segment thus allowing the possibility of creating a quadruple action in conjunction with at least one adjacent electrode, said segments covered with a deposited high-resistance conducting film to prevent charging effects.

Abstract: An electron gun for a color CRT has three cathodes disposed in parallel to each other, first to fifth grid electrodes and a convergence deflector. The electron gun is additionally provided with a tetrode magnetic field generator including a pair of permanent magnets having an astigmatic effect of the central beam of the electron gun on the cathode side of the convergence deflector. An astigmatism eliminator is provided to cancel astigmatic aberration of the side beams of the electron gun near the position where the electron beams are converged. The astigmatism eliminator is composed of a fifth grid electrode whose entrance has an electron beam passing hole of nearly elliptic shape.

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: Disclosed is a color cathode ray tube equipped with a main electronic lens section for focusing a plurality of in-line electron beams on a screen section. The main electronic lens section includes a plurality of grids each having electron-beam through holes and securely supported by a plurality of insulating supports. At least one of the grids has a rectangular cup portion with a substantially rectangular cross section for commonly enclosing the plurality of in-line electron beams and a face having electron-beam through holes formed at least at one end and substantially perpendicular to the rectangular cup portion. The ratio of an outside diameter L.sub.H of the substantially rectangular portion in a long-axial direction to an outside length L.sub.S thereof in a short-axial direction, L.sub.H /L.sub.S, is set to 2.5<L.sub.H /L.sub.S <4.4, and the ratio of the outside length L.sub.S to a diameter D.sub.V of the electron-beam through holes in the same short-axial direction, L.sub.S /D.sub.V, is set to 1.

Abstract: A display tube having a deflection coil support with a field deflection coil system at its outer side and a line deflection coil system at its inner side. The gun-sided end of the line deflection coil system is situated in a plane parallel to the wall of the display tube. The outer side of the coil support is surrounded by an auxiliary deflection coil system, preferably in a printed form, against the inner and for outer surface of a synthetic material supporting cylinder. This assembly, which can be used particularly for scan velocity modulation purposes, is at least partly arranged between the field deflection coil system and the wall of the display tube, while it partly overlaps the gun-sided end of the line deflection coil system.

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 color display tube system comprising an electron gun for producing three co-planar electron beams, and including a main deflection system which in operation generates deflection fields of the self-convergent type, and an auxiliary deflection system which in operation generates a 45.degree. magnetic 4-pole field facing the electron gun and moving the outer electron beams away from each other, and a 45.degree. magnetic 4-pole field facing the display screen and moving the outer beams towards each other.