Abstract: A structure for damping vibration of a shadow mask fitted to a mask supporting body in a flat cathode ray tube is provided. The structure includes a plurality of damper wires each fastened under tension to the mask supporting body for strapping the shadow mask between beam pass through holes in the shadow mask. The damper wires and the shadow mask are configured such that a first order natural frequency of vibration of the damper wire falls outside a range within ±10% of a third order natural frequency of vibration of the shadow mask. The structure improves vibration damping, reduces the number of required components and simplifies the fabrication process.

Abstract: The method of assembling an electron gun for a cathode-ray tube comprises the steps loading of at least two electrodes (20, 70) one above the other, adjusting the distance between the electrodes along the longitudinal axis of the gun, and loading the electrodes between the two jaws (30, 30′, 31, 31′, 60, 60′, 61, 61′) of a positioning tool (35). The further includes positioning of the electrodes in the plane perpendicular to the longitudinal axis by clamping the jaws of the tool in a single direction, until a pressure is exerted on four corners (23) of each electrode and retaining by hot insertion of glass beads (40) into claws arranged on the periphery of the electrode openings of the positioning tool. The tool holds the electrodes in planes perpendicular to the longitudinal axis of the gun.

Abstract: At least one of electrodes of an electron gun assembly is constructed by coupling at least first and second electrode members arranged in a direction of passing of electron beams. The first electrode member has a projecting portion on an end face thereof, which is to be coupled to the second electrode member disposed adjacent to the first electrode member. The first electrode member is coupled to the second electrode member via the projecting portion.

Abstract: An in-line electron gun for a colored cathode ray tube has an electronic field correction plates with a central key-hole shaped aperture with two opposite straight lines and two side apertures each with a plurality of vertical and horizontal in addition to a plurality of circular arcs of different radii.

Abstract: A main lens is composed of a dynamic focus electrode, a first auxiliary electrode, a second auxiliary electrode and an anode, which are successively arranged in a direction of travel of electron beams. A sub-lens provided on a cathode side of the main lens is composed of a third grid, a fourth grid and a fifth grid. The first auxiliary electrode is connected to the fourth grid, and both are connected to a voltage supply terminal on a resistor near the fourth grid. A fixed focus voltage is applied to the third grid and fifth grid sandwiching the fourth grid.

Abstract: The present invention discloses an electron gun assembly for color cathode ray tube capable of preventing a moiré phenomenon and improving the resolution.

Abstract: Disclosed is a cathode ray tube with an electron gun capable of improving a resolution of an image by preventing electron beams from striking electrodes and efficiently controlling a spot size that is susceptible to a change in current capacity.

Abstract: Electrodes of an electron gun including a pair of first and second outer rim electrode members installed to face one another and where large diameter electron beam apertures through which three electron beams pass are respectively formed, and first and second inner electrode member installed in the outer rim electrode members, respectively, and where three small diameter electron beam apertures are formed to have an in-line shape. In the above electrodes, a burring portion is formed at the edge of the large diameter electron beam aperture of the first outer rim electrode member at one side of the outer rim electrode members facing each other, and the vertical diameter of the electron beam aperture formed in the middle of the small diameter electron beam apertures formed at the first inner electrode is formed to be greater than those of the two other small diameter electron beam apertures.

Abstract: In-line type electron gun in a color cathode ray tube including a pre-focusing lens part having at least two electrodes for focusing electron beams, a main lens part having two, or more than two electrodes for focusing the electron beams onto a screen, and at least one electrostatic field controlling electrode in the electrodes of the main lens part having a center electron beam pass through hole and two outer electron beam pass through holes, wherein each of the outer electron beam pass through holes has a form a circular hole and a rectangular hole are combined therein, the rectangular hole having a height ‘V2’ greater than a vertical diameter ‘V1’ of the center beam pass through hole of the electrostatic field controlling electrode, thereby permitting an excellent focusing and improving assembly work.

Abstract: The present invention relates to a frame for a color CRT having a square framework includes a plurality of beads for strengthening stiffness of the frame formed on the framework including corner portions in order to prevent distortion of the shadow mask. The beads formed on the corner portions are stepped beads having at least two steps. The present invention is capable of strengthening the stiffness of the frames, and increasing an impact character and a vibration character by improving shapes of the beads on the corner portions where stress is concentrated.

Abstract: A cathode ray tube comprising an electron source and an electron beam guidance cavity having an input aperture and an output aperture, wherein at least a part of the wall of the electron beam guidance cavity near the output aperture comprises an insulating material having a secondary emission coefficient &dgr;1 for cooperation with the cathode. Furthermore, the cathode ray tube comprises a first electrode connectable to a first voltage source for applying, in operation, an electric field with a first field strength E1 between the cathode and the output aperture. &dgr;1 and E1 have values which enable electron transport through the electron beam guidance cavity. A second electrode is placed between the cathode and the cavity. The second electrode is connected to a second voltage source for applying, in operation, an electric field with a second field strength E2 between the cathode and the second electrode for controlling the emission of electrons.

Abstract: A cathode ray tube has an electron gun including an indirectly heated cathode structure having a heater therein. The heater has a major heating portion formed of a spirally wound heating wire and two leg portions connected to opposite ends of the major heating portion. The two leg portions are welded to electrical conductors for applying voltages thereto at portions in the vicinity of open ends of the two leg portions, respectively, and the heater is covered with an insulating film except for the portions for welding. The two leg portions includes at least five layers of winding formed by spirally winding heating wires identical with the heating wire of the major heating portion, and the numbers of turns per unit length in each of the at least five layers of winding are smaller than a number of turns per unit length of the heating wire of the major heating portion.

Abstract: An electron gun for a color cathode ray tube (CRT) includes at least one auxiliary quadruple lens forming unit for making an electron beam diverging in the vertical direction and focused in the horizontal direction by a plurality of focus electrodes, at least one first quadruple lens forming unit for making the electron beam passing through the auxiliary quadruple lens focused in the vertical direction and diverging in the horizontal direction, and at least one second quadruple forming unit for making the electron beam passing through the first quadruple lens diverging in the vertical direction and focused in the horizontal direction, installed between the screen electrode of a triode portion and a final acceleration electrode, which are sequentially arranged in a direction from a screen electrode to a fluorescent film of a cathode ray tube. Thus, a horizontal resolution at the periphery of a screen is improved.

Abstract: A cathode-ray tube electron gun can alleviate unwanted radiation caused when cathodes and a first electron gun constitute an antenna by increasing the number of conduction leads of a first electrode of a cathode-ray tube electron gun from one to a plurality of conduction leads.

Abstract: An electron gun for use in a cathode ray tube (CRT) includes a source of energetic electrons, i.e., a cathode, a beam forming region for forming the energetic electrons into a narrow beam, an arrangement for deflecting the beam over a display screen, and a focus arrangement for focusing the beam on the display screen in the form of a small spot in forming a video image. The beam forming region includes a G1 control grid, a G2 screen grid and a portion of a G3 grid in facing relation to the G2 grid, where each grid includes a respective aperture through which the electron beam is directed, with the apertures aligned along a common axis. The size of the aperture on the side of the G2 grid in facing relation to the G1 grid forms a first focusing lens and is smaller than the size of the aperture on the opposed side of the G2 grid in facing relation to the G3 grid which forms a second focusing lens.

Abstract: The stray emission in an electron gun comprising a main lens system with one or more intermediate electrodes (42, 43, 44) between the focus electrode (41) and the anode electrode (45) is reduced if at least one of the apertures of the main lens system following the focus electrode has apertures which are smaller than those of the focus electrode. The optimal stray emission situation can be found by designing all the apertures of the main lens system. In order to manufacture an electron gun according to the invention, it is advantageous to have an outside reference system for gun mounting, because it will no longer be possible to center the electrodes on pins through the apertures.

Abstract: A cathode ray tube has an anode of a large-diameter cylinder portion on its phosphor screen side and a small-diameter cylinder portion on its cathode side connected together, and a focus electrode formed of a large-diameter cylinder portion of a diameter larger than that of the small-diameter cylinder portion of the anode and a small-diameter cylinder portion having a diameter smaller than that of the small-diameter cylinder portion of the anode, the large-diameter and small-diameter cylinder portions being connected together. The large-diameter cylinder portion of the focus electrode is disposed concentrically within the large-diameter cylinder portion of the anode. The anode and a first electrode facing a cathode side end of the focus electrode are electrically connected together within the cathode ray tube. The following relationship is satisfied: −LP+184.9≧LG4≧0.0004 LP3−0.1571 LP2+21.006 LP−922.41, LP≧131.

Abstract: A cathode ray tube according to the present invention include a cold cathode electron gun, the cold cathode electron gun including a cold cathode array for emitting electrons through field emission, a gate electrode for controlling the field emission, a first selective electrode provided around the cold cathode array and the gate electrode, and a second selective electrode opposing the first selective electrode, and the second selective electrode is adapted to have a lower potential than the gate electrode and the first selective electrode. In accordance with this configuration, the divergence of electron beams emitted from any positions in the cold cathode array can be converged uniformly upon removing electron beams emitted at a great emission angle. This allows the electron beams thereafter to be made narrower by an electrostatic lens. As a result, the present invention can provide a cathode ray tube capable of forming a high-resolution image.

Abstract: Electron gun in a color CRT including a plurality of stem pins for applying different voltages, an acceleration electrode, a third electrode, a fourth electrode, and a static electrode, for forming pre-focus lenses, a dynamic electrode and an anode for forming a main focus lens, the static electrode and the dynamic electrode for forming a quardrupole lens, bead glass for holding the foregoing electrodes at fixed distances, a first wire having one end welded to the dynamic electrode, the other end welded to the stem pin a dynamic voltage applied thereto, and a body between the one end and the other end having an evasive form so as not to come into contact with neighboring members, and a second wire having one end welded to the third electrode, the other end welded to the stem pin a static voltage applied thereto, and a body between the one end and the other end having an evasive form so as not to come into contact with neighboring members, thereby minimizing noise, spark, and neck damage.

Abstract: A color cathode ray tube includes a generally rectangular phosphor screen having a plurality of phosphor pixel line-trios each formed of three color phosphor pixels arranged in a line and a black matrix of opaque material having holes for defining areas of the phosphor pixels which are viewed through a panel, a shadow mask having a large number of mask apertures for color selection, and an electron gun. A distribution in area of center phosphor pixels of the phosphor pixel line-trios has sharp decreases, going from a center of the phosphor screen toward a periphery of the phosphor screen, in the vicinity of at least one of (a) top and bottom sides and (b) right and left sides, of a rectangular useful display area of the phosphor screen.

Abstract: A multi-beam color index cathode ray tube (CRT) includes vertically spaced, horizontal phosphor stripes on the inner surface of its display screen. The parallel phosphor bands are arranged in groups of three, with each phosphor stripe in a group providing a respective one of the three primary colors of red, green and blue. An electron gun directs three electron beams onto the display screen, with the three electron beams deflected over the display screen in unison in a raster pattern. The three electron beams are focused in the form of three spots on the display screen, with each spot coincident with a respective horizontal phosphor stripe of a given color. The intensity of each electron beam is independently modulated as it sweeps across the width of the display screen by a respective color video signal in accordance with the displayed image.

Abstract: In an electron beam apparatus comprising an enclosure in which an electron-emitting device having an electron-emitting region between opposite electrodes is disposed, the electron-emitting device exhibits such a characteristic as that an emission current is uniquely determined with respect to a device voltage. The interior of the enclosure is maintained under an atmosphere effective to prevent structural changes of the electron-emitting device. An image-forming apparatus comprises an enclosure in which an electron source and an image-forming member are disposed, the electron source comprising the above electron-emitting device. An emission current is stable with a very small change in the amount of electrons emitted, a sharp image is produced with high contrast, and gradation control is easily carried out.

Abstract: An electrode of an electron gun for a cathode ray tube including a first electrode member having a large-diameter electron beam passing aperture through which three electron beams pass, and a second electrode member in the first electrode member so as to be spaced apart from the edge of the first electrode member and having three small-diameter electron beam passing apertures, wherein a slanted portion extends from the edge of the first electrode member toward the interior of the large-diameter electron beam passing aperture.

Abstract: A main lens of an electron gun of a cathode ray tube is provided. The main lens for receives a plurality of parallel and co-planar electron beams emitted by the electron gun. The lens focuses each electron beam along a respective one of a plurality of focal axes incident to a display surface. A first grid electrode is positioned substantially orthogonally with respect to the plurality of electron beams, the grid electrode includes a plurality of apertures.

Abstract: An electrode unit of an electron gun for a cathode ray tube including an outer rim electrode having a large-diameter electron beam passing hole through which three electron beams pass, and an inner electrode installed within the outer rim electrode and having a central electron beam passing hole disposed at its center and side electron beam passing holes disposed at opposite sides of the central electron beam passing hole. The side electron beam passing holes each have first and second curved sides along the sides closest to the central electron beam passing hole and opposite those sides, and linear portions connecting the first and second curved portions. The vertical and horizontal dimensions of the side electron beam passing holes are equal to each other.

Abstract: A CRT for the display of a large screen television set which includes a tube envelope having a pair of tube necks and a phosphor display screen, a pair of electron guns arranged in a same horizontal plane and each positioned in a different one of the tube necks, for directing dual electron beams to impinge upon the phosphor display screen, and magnetic deflection yokes for horizontally deflecting the dual electron beams to produce a visual display of partially overlapping dual raster scans on the display screen.

Abstract: A tensioned shadow mask for a color cathode ray tube (CRT) adopting the same. In the color CRT including a faceplate on an inner side, a phosphor screen, a tensioned mask, and frame assembly secured to the faceplate, a funnel connected to the faceplate, the funnel having a neck portion and a cone portion, an electron gun in the neck portion of the funnel, and a deflection yoke on the cone portion of the funnel, the tensioned mask including a series of parallel strips separated by slits at an interval, tie bars interconnecting adjacent strips and defining slits at intervals, and dummy bridges disposed between adjacent tie bars, the dummy bridges respectively extending from adjacent strips toward each other in respective slits but not interconnecting the adjacent strips.

Abstract: A three in-line beam type color CRT includes a focus electrode and an anode. The focus electrode includes a first focus sub-electrode supplied with a first fixed focus voltage and a second focus sub-electrode supplied with a second fixed voltage superposed with a dynamic voltage synchronized with beam deflection, and the first and second focus sub-electrodes form a quadrupole lens therebetween. Two side electron beams are deflected toward a center electron beam with increasing dynamic voltage in the quadrupole lens. An axial distance Lgf (mm) from a cathode side end of the first focus sub-electrode to an anode side end of the second focus sub-electrode, an axial distance Ls (mm) from the end of the second focus sub-electrode to the phosphor screen, and a useful diagonal dimension D (mm) of the phosphor screen satisfy 0.06×Ls (mm)≦Lgf (mm)≦26 (mm) and 1.50≦D/Ls≦1.70.

Abstract: Cathode ray tube having an electron gun which is modified with respect to the electron gun having three equidistant cathodes lying “in line”. The cathode for generating the green (central) beam is offset with respect to its position in an in-line gun, and the grids in the focus and/or triode part of the gun have been modified to provide at least one kink in the trajectory of the green beam to restore convergence.

Abstract: A color picture tube has an electron gun assembly directed to a shadow mask spaced from a fluorescent screen by a predetermined distance in the bulb thereof, and a high voltage is supplied through a conductive layer formed on the inner surface of the bulb and a bulb spacer to an accelerating electrode of the electron gun assembly, wherein the contact resistance between the conductive layer and the bulb spacer is reduced to be equal to or less than 1 kilo-ohms so that the accelerating electrode is free from electrical influence of parabola voltage applied to a focusing electrode, whereby an undesirable lens is prevented and, accordingly, the electron beams are not deviated from the target trajectories.

Abstract: Single beam color CRT of the beam tracking type having a display screen comprising a plurality of parallel phosphor lines, the CRT being equipped with a Distributed Main Lens type electron gun. The distributed main lens has a plurality of oblong grids which each have a single, oblong, beam passing aperture. The longitudinal axes of the grids and of the apertures are transverse to the direction of the phosphor lines. Correction means are provided to compensate for the astigmatism introduced by the main lens.

Abstract: An intermediate electrode at a middle voltage which takes a value between a focusing voltage and an anode voltage is disposed between a focusing electrode and an anode of an in-line type electron gun. The intermediate electrode has a single opening whose diameter in the horizontal direction (in-line direction) is greater than the diameter thereof in the direction perpendicular to the horizontal direction so as to allow three electron beams to pass therethrough. The intermediate electrode also has a plate electrode provided therein with three electron beam apertures which respectively allow three electron beams to pass therethrough. Inside of the focusing electrode, a plate electrode provided with three electron beam apertures is provided.

Abstract: For use in a beam index color cathode ray tube (CRT), a multi-beam group electron gun directs first and second groups of vertically aligned electron beams on respective parallel, horizontally aligned color phosphor stripes on the CRT's display screen. Each group of electron beams includes three beams, one for each of the three primary colors of red, green and blue. The first and second electron beam groups are horizontally offset from one another, with the upper, intermediate and lower electron beams in each group tracing the same horizontal phosphor stripe as the beams scan the display screen and with a time delay provided to synchronize the video information of both electron beam groups. A color video signal is provided either to a respective cathode or to a respective segmented conductive portion containing a beam passing aperture in the electron gun's G1 control grid for individually modulating each beam with color video image information.

Abstract: Cathode venting for electron guns is improved by forming one or more vent holes around the apertures in the triode and any pre-focus lens. This configuration places the vent holes next to the active area of the cathode and provides a line of sight from the cathode to the funnel. If separate alignment holes are used to protect the aperture, one or more vent holes are provided in addition to the alignment holes. The pattern of vent and alignment holes is preferably rotationally symmetric about the aperture so that they do not effect the beam.

Abstract: A dual-gun, single neck CRT focuses two beams, with significantly differing energies, onto a secondary emission target while maintaining compatibility with a standard fourteen-rotation stem and achieving FTU in excess of 95%. A pair of Einzel guns (write and erase) are mounted in parallel and aligned in the vertical direction rather than the horizontal inside the CRT. The write and erase guns are configured to share a common second accelerator electrode, a common final accelerator electrode, mounting beads and a magnetic deflection yoke. The guns' focus voltages are independently adjusted so that both the write and erase beams have the same focal length.

Abstract: A projection tube has a phosphor-coated faceplate at one end of a vacuum envelope and a plural-beam providing electron lens structure at the opposite end thereof. The electron lens structure includes four electrodes having axially-aligned apertures defining parallel channels for the plural electron beams to pass through to be focused and converged onto a small spot on the faceplate. The first and second electrodes of the electron lens structure shape the electron beams and the third and fourth electrodes thereof converge and focus the electron beams toward the same location on the faceplate. The potential applied to the fourth electrode is at or close to the potential at the phosphor, and is substantially higher than the potential applied to the third electrode. The lens structures of the third and fourth electrodes may each include an inner electron lens structure and an outer electron lens structure.

Abstract: A cathode ray tube has an electron gun including an indirectly heated cathode structure having a heater therein. The heater has a major heating portion formed of a spirally wound heating wire and two leg portions connected to opposite ends of the major heating portion. The two leg portions are welded to electrical conductors for applying voltages thereto at portions in the vicinity of open ends of the two leg portions, respectively, and the heater is covered with an insulating film except for the portions for welding. The two leg portions includes at least five layers of winding formed by spirally winding heating wires identical with the heating wire of the major heating portion, and the numbers of turns per unit length in each of the at least five layers of winding are smaller than a number of turns per unit length of the heating wire of the major heating portion.

Abstract: A color cathode ray tube having at least an electron gun and a fluorescent screen. The electron gun forms a plurality of electron beams arranged in line and includes a focusing electrode and an anode having a gap and providing a main lens for focusing and accelerating the electron beams. The focusing electrode includes at least a first division electrode and a second division electrode having the same potential and arranged with a gap in the axial direction of the tube. The second division electrode is opposed to said anode and has, in the opposed surface thereof, a single opening for passing the plurality of electron beams in common. The second division electrode is opposed to the first division electrode and has, in the opposed surface thereof, individual electron beam passing openings for the respective electron beams.

Abstract: A three in-line beam type color CRT includes a focus electrode and an anode. The focus electrode includes a first focus sub-electrode supplied with a first fixed focus voltage and a second focus sub-electrode supplied with a second fixed voltage superposed with a dynamic voltage synchronized with beam deflection, and the first and second focus sub-electrodes form a quadrupole lens therebetween. Two side electron beams are deflected toward a center electron beam with increasing dynamic voltage in the quadrupole lens. An axial distance Lgf (mm) from a cathode side end of the first focus sub-electrode to an anode side end of the second focus sub-electrode, an axial distance Ls (mm) from the end of the second focus sub-electrode to the phosphor screen, and a useful diagonal dimension D (mm) of the phosphor screen satisfy 0.06×Ls (mm) ≦Lgf (mm)≦26 (mm) and 1.50≦D/Ls≦1.70.

Abstract: A color cathode ray tube includes a phosphor screen, an in-line type electron gun having an electron beam generating section for projecting three electron beams arranged in parallel with each other in a horizontal plane toward the phosphor screen, a focus electrode, and an anode adjacent to the focus electrode and forming a main lens in cooperation with the focus electrode for focusing the electron beams on the phosphor screen. The focus electrode includes at least a first focus sub-electrode and a second focus sub-electrode on the order named from the cathode, the first focus sub-electrode and the second focus sub-electrode forming an electrostatic quadrupole lens therebetween.

Abstract: A color cathode ray tube is provided with an electron gun having a voltage-dividing resistor having a stable and good voltage supplying function. The voltage-dividing resistor has an insulating substrate on which a resistor pattern and a terminal-connecting conductive film are formed, and a terminal having a first flange portion, a connecting portion, a tubular portion and a second flange portion. The first flange portion partly has a convex portion for electrical connection to the terminal-connecting conductive film, and the second flange portion is doubled. This construction provides reliable electrical connection between the terminal and the terminal-connecting conductive film.

Abstract: Display device having an in-line electron gun with a main lens, in which the anode voltage ranges between 16 and 22 kVolt and the parameter Va0.5.p3/2 is greater than 50 kVolt0.5 mm3/2. A reduction of the total power can be achieved without sacrificing front-end performance.

Abstract: An auto-stereoscopic display device comprises a plane viewing screen, a plane cathode, and a plane permanent magnet. A two dimensional array of rows and columns of channels extends between opposite poles of the magnet for receiving electrons from the cathode. A phosphor layer is disposed between the screen and the magnet and having a plurality of pixels each corresponding to a different channel. Grid electrode means is disposed between the cathode and the magnet for selectively controlling flow of electrons from the cathode through each channel to the corresponding pixel in response to input video data. Deflection anode means is disposed on the side of the magnet remote from the cathode for sequentially deflecting, orthogonally to the columns, each electron beam to different parts of the corresponding pixel in response to an input video clock signal.

Abstract: An in-line type color Braun tube having a fluorescent screen and a shield cup at an end of an electron gun, the shield cup including a cylindrical side wall and a bottom having a center electron beam passing hole and two side electron beam passing holes aligned in a horizontal direction. A convergence correcting member including a base and a pair of horizontal plates, the base and horizontal plates being a one piece member, and a bottom member of the base being cross-shaped and including two side electron beam passing holes and a center electron beam passing hole. A pair of horizontal plates sandwiches an electron beam passing through each of the side electron beam passing holes, in a direction vertical to the electron beam.

Abstract: A color cathode ray tube having an electron gun which includes a one piece electrode plate. The one piece electrode plate has three beam passage holes in an in-line arrangement and bead supports. The one piece electrode plate has two portions including a portion having the beam passage holes and a portion having the bead supports which are formed as a one piece structure. The portion having the beam passage holes has a thickness larger than a thickness of the bead supports portion and the one piece structure has steps and continuous walls between the two portions.

Abstract: To prevent rotation of a generally flat, or planar, grid having three inline beam passing apertures, where the two outer apertures are asymmetric in shape, during assembly of a multi-beam electron gun for use in a color cathode ray tube (CRT), an electron gun alignment jig having three inline generally cylindrical mandrels in combination with a generally flat spacer plate is used. Each of the three mandrels is inserted in a respective grid aperture and the grid is placed in contact with the flat spacer plate. The flat spacer plate includes a recessed portion with an alignment slot. The grid includes a lateral alignment tab adapted for insertion in the spacer plate's matching alignment slot in a tight-fitting manner. With the alignment tab inserted in the alignment slot, the three inline apertures are in precise alignment in the alignment jig and grid rotation is prevented to facilitate electron gun assembly.

Abstract: An internal resistor within a color cathode ray tube (CRT) is connected to a voltage source and is coupled across a G4 grid and a G6 grid of the CRT's multi-grid quadrupole (QPF) electron gun. De-coupling the G4 grid from the G2 grid in the electron gun's prefocus lens and operating the G4 grid at a higher voltage as used in the gun's high voltage main focus lens moves the equivalent lens of the prefocus and main focus lenses toward the CRT's display screen and reduces electron beam magnification and spot size for improved video image definition and focusing.

Abstract: A color cathode ray tube has at least an electron gun, constituted by a cathode for forming a plurality of electron beams arranged in line and a plurality of electrodes, and a fluorescent screen, wherein the plurality of electrodes including an anode are arranged in the axial direction of the tube and have dissimilar potentials, and a main lens is constituted of the anode and another electrode neighboring the anode. The electrode neighboring the anode includes at least two division electrodes having the same potential and being arranged with a gap in the axial direction of the tube, and one of the division electrodes is opposed to the anode and has, in the opposed surface thereof, a single opening for passing the plurality of electron beams in common. The one division electrode opposed to the anode has a length in the axial direction of the tube that is from about 1.0 to about 1.6 times as great as the diameter of the single opening in a direction at right angles with the in-line direction.

Abstract: A display has a cathode ray tube (CRT) provided with a multiplicity of electron beams or beam sets. Each of the beams has its own auxiliary beam control assembly including deflection means. Each beam assembly is directed to energize a prescribed portion of the display format area. The typical application may employ two to six beam sets and is useful to reduce total depth and bulk of CRT's having high aspect ratios and/or large size. The displayed area shows substantially no visible boundaries (tiling) between portions.

Abstract: A cathode-ray tube having an electron gun which includes an electrode plate (E) in which a portion having three beam passage holes (H) and a portion having bead supports (S) are formed as a unitary or one piece structure, the two portions having different thicknesses (T.sub.1, T.sub.2), and the steps being inclinedly formed along the boundaries of the two portions. Since the portion having beam passage holes and the portion having bead supports are formed as a unitary or one piece structure easily and highly precisely in the electrode plate, the conventionally employed process of welding can be omitted, and thereby the productivity is raised and the manufacturing cost is decreased. Moreover, use of the material having the steps formed in advance contributes to increasing the productivity and preventing the machining tools from being damaged during the press-forming.