Abstract: In an inline electron gun for use in a color cathode ray tube (CRT), a fixed, or static, electrostatic quadrupole in the low voltage beam forming region (BFR) exerts a negative astigmatism on the electron beams in reducing beam horizontal cross-section and compensating for the horizontal under-focusing of the beams by the CRT's self-converging magnetic deflection yoke. The negative astigmatism is compensated for by a dynamic electrostatic quadrupole in the CRT's main focusing lens. The electrostatic quadrupole in the CRT's BFR includes either a plurality of spaced, horizontally oriented, aligned, elongated indentations in the G.sub.2 facing surface of the G.sub.1 control grid or a plurality of spaced, vertically oriented, elongated indentations in the G.sub.1 facing surface of the G.sub.2 screen grid, where each of the indentations has an associated through-hole circular aperture through the grid.

Abstract: A Pierce electron gun is provided having a cathode, a focusing electrode surrounding the cathode, and an anode disposed a fixed distance from the cathode and having an opening therethrough. The electron gun has at least one grading electrode disposed between the focusing electrode and the anode. The grading electrode controls shape of equipotential lines of an electric potential difference provided between the anode and the cathode, to purposely reduce field gradient levels formed by the electric potential difference. The grading electrode further has a double radial bend having an inner radial curve of a first radius and an outer radial curve of a second radius.

Abstract: An electron gun for a color cathode ray tube is formed such that parallel vertical blades are extending toward cathodes formed at both edges of each electron beam passing hole in the outgoing plate of a focus electrode. Horizontal blades extending toward the cathodes at a predetermined length are formed at the edges of the top and bottom portions of electron beam passing holes in the incoming plate of a dynamic focus electrode. Thus, the horizontal blades are inserted into the electron beam passing holes of the focus electrode, which reduces astigmatism due to deflection aberration and improves the focusing characteristics.

Abstract: A cathode ray tube comprising an electron gun having two oppositely arranged conductor patterns. In operation, the electron beams (or electron beam) move between the conductor patterns. It has been found that the electron-optical functions, such as focusing and converging the electron beams, which are fulfilled by electrodes in a conventional gun can be fulfilled by two flat-conductor patterns. Said conductor patterns can be accurately manufactured and arranged relative to each other. This enables the manufacture of complicated lens systems.

Abstract: An electron gun for a cathode ray tube arranged in sequence following by a cathode, a first grid electrode, a second grid electrode, a first accelerating/focusing electrode, and a second accelerating/focusing electrode from the lower on the axis of the cathoderay tube, comprises a third grid electrode assembly including an inter-grid assembly installed between the lower electrode and the upper electrode which is made into the first accelerating/focusing electrode, a main electrostatic focusing lens mounted between the fourth grid electrode to be considered as the second accelerating/focusing electrode and the upper electrode of the third grid electrode assembly and other electrostatic focusing lens formed between the inter-grid assemblies which is installed in the third grid electrode assembly, in which the drift space of the electron beam is secured in the electron gun and the focusing electrode of the main electrostatic focusing electrode, which is applied to a lower voltage, is devided into two to get the

Abstract: An electron gun for a color picture tube comprising six spaced grid electrodes aligned in the direction that electron beams proceed. The fourth grid electrode comprises a pair of plate-shaped grid electrodes arranged to form a space therebetween and electrically connected with each other. Both plate-shaped grid electrodes are also connected with the second of the grid electrodes so that they receive the same voltage. The space defined between both plate-shaped grid electrodes is variable within the range corresponding to 0.29 to 1.15 times the thickness of each plate-shaped grid electrode. By the construction of the fourth grid electrode, the spaces defined between respective adjacent grid electrodes can be reduced. As a result, the generation of undesirable stray is restricted. Also, the kind of using electrodes can be widely selected, since the space defined between one side fourth grid electrode and the other side fourth grid electrode can be varied.

Abstract: An electron gun for color cathode ray tube is disclosed which includes: a triode section for forming the thermionic electrons from the cathode into electron beams; a multistep focusing type electrostatic lens means for focusing the electron beams from the triode section. The characteristic feature of the present invention is that: an electrostatic lens is formed through the combination of a UPF type electrostatic lens and a BPF type electrostatic lens; and another UPF type electrostatic lens is formed between the electrodes disposed closely to the triode section among the UPF type or BPF type electrostatic lens forming electrodes, so as for a multiplex multistep focusing type electrostatic lens to be formed. According to the present invention, the spherical aberration acting on the electron beams at the main electrostatic focusing lens can be largely eliminated, and therefore, a high quality picture can be obtained.

Abstract: In an electron gun for cathode ray tubes in which the second of three focusing electrodes is divided into first, second, and third auxiliary electrodes, applying a first dynamic voltage synchronous with vertical and horizontal deflection signals to the first and third auxiliary electrodes, a second dynamic voltage synchronous with the deflection signals to the second auxiliary electrode, and a static focusing voltage higher than the maximum of the first and second dynamic voltages to the first and third focusing electrodes. The electron gun uses two dynamic focusing voltages in a low voltage driving method for low dynamic focusing voltages, thereby greatly reducing the possibility of an arc discharge between electrodes and compensating for astigmatism of the electron beam due to the non-uniform magnetic field of the deflection yoke. A sharp picture is achieved by improving the focusing of the electron beam.

Abstract: A limiting aperture disposed in a low voltage, beam forming region (BFR) of an electron gun in a cathode ray tube (CRT) provides reduced electron beam spot size with low power dissipation. The limiting aperture is located in a low voltage, electrostatic field-free region, preferably in the screen grid electrode G.sub.2, where the field-free region is formed by increasing the thickness of the screen grid electrode G.sub.2 to 1.8 times the diameter of a pair of circular recessed portions in opposing surfaces of the screen grid electrode G.sub.2 which are separated by the small diameter limiting aperture on the electron gun's axis through which the beam is directed. A narrow, relatively electrostatic field-free zone is thus formed in the center of the screen grid electrode G.sub.2 which is maintained at a relatively low voltage, i.e., ranging from approximately 300 V to less than 12% of the anode voltage.

Abstract: An electron gun for a color cathode-ray tube includes a triode, a pre-stage auxiliary electrostatic focusing lens, a fourth grid electrode, a first accelerating/focusing lower electrode assembly, and a main electrostatic focusing lens formed between a first accelerating/focusing upper electrode assembly and a second accelerating/focusing electrode. In the electron gun, the electron beam horizontally extended by the magnetic quadrupole lens of the deflection magnetic field is compensated by vertically extending the horizontally extended electron beam before the deflection magnetic field is entered by the electrostatic quadrupole lens which varies according to the deflected amount of the electron beam and round beam sports obtained in the vicinity of the screen edge as well as at the center of the screen, so that the halo portions of a low electron density surrounding the core portion of a high electron density forming a beam spot is greatly reduced to obtain a good resolution characteristic.

Abstract: The invention provides an in-line electron gun in which first astigmatic lens fields that are convergent in a horizontal direction and divergent in a vertical direction are produced between a first focusing grid and a second focusing grid, and second astigmatic lens fields that are divergent in a horizontal direction and convergent in a vertical direction are produced upstream of the first focusing grid. The lens magnifications in both horizontal and vertical directions can be made substantially equal, so that it is possible to achieve a satisfactory resolution over the entire area of the phosphor screen and also to prevent moire occurrences.

Abstract: An inline electron gun for a multi-beam color cathode ray tube (CRT) corrects for green (center) electron beam vertical spherical aberration by enlarging the vertical dimension of the center portions of common lens apertures in adjacent grids in the electron gun. Increasing the vertical dimension of that portion of each of the aforementioned grid apertures through which the green electron beam transits reduces the vertical spot size of the green beam without degrading other electron gun operating characteristics. The inventive grid aperture arrangement is particularly adapted for use in a combined optimum tube and yoke (COTY) color CRT.

Abstract: The gun comprises a cathode, a control grid, a first anode a second anode and a third anode. Preferably a beam width limiting aperture is provided in the first anode. In one example the current modulating voltage applied to the grid is 0 to -50V, the voltage applied to the first anode is +5 kV, the focus voltage applied to the second anode is +500V, and the EHT voltage applied to the third anode is +25 kV. A main focussing lens is formed by the second and third anodes, but the spacing of the first and third anodes is small so that the focussing effect is also substantially dependent on the voltage of the first anode. The field strength between the grid and first anode is high, which combined with the high first voltage produces a small crossover.

Abstract: An electron gun for use in a color picture tube includes electrodes forming at least one unipotential focusing lens for focusing electron beams. An electrode disposed between first and second electrodes forming a unipotential focusing lens includes first and second plate-shaped members. The first member forms, in cooperation with the first electrode, a focusing lens having an electrostatic field weaker in the vertical direction than in the lateral direction. The second member forms, in cooperation with the second electrode, a focusing lens having an electrostatic field weaker in the vertical direction than in the lateral direction. The electron gun removes halos appearing in the peripheral region of the tube screen.

Abstract: A dynamic focusing electron gun for high resolution includes a triode part and a main lens. The main lens includes a first focusing electrode disposed proximate the triode part, a second focusing electrode disposed proximate an anode electrode, a static potential electrode and a dynamic potential electrode disposed between the first and second focusing electrodes to form a dynamic quadrupole lens. The dynamic focusing electron gun produces a high resolution image with a small radius beam spot with low astigmatism, low spherical aberration, and good voltage endurance characteristics.

Abstract: An in-line type electron gun for a cathode ray tube includes a cathode, a control grid, a screen grid, and a main lens including a final focus electrode and an anode forming a major lens, at least one of the focus electrode and anode including a first member with three independent beam passing holes disposed at a beam passing plane thereof and a second member with a common beam passing hole disposed at a beam passing plane thereof, the beam passing planes being separated from each other by a fixed distance. According to the present invention, electron beam control errors originating from manufacturing errors can be reduced to a great degree. The electron gun of the present invention is simple and convenient to manufacture with a low product defect rate.

Abstract: An electron gun for a cathode ray tube includes a cathode for generating electrons; a charged element for receiving electrons from the cathode and for forming a beam crossover; and an asymmetrical unipotential-type focus lens for forming an image of the crossover at a distance from the gun, comprising a prefocus electrode arrangement for forming a prefocusing field and a main focus electrode arrangement for forming a main focusing field, the prefocus electrode arrangement being constructed, configured and adapted to be excited to cause the prefocusing field to be weaker than the main focusing field such that at low beam currents the effective focal plane of the focus lens is moved forwardly away from the cathode and beam spot size performance is thereby improved, and such that the beam exit diameter is increased for reduced space charge effects and thereby improved high beam current performance.

Abstract: At least one of grid electrodes which serves as a main lens of an electron gun for use in a color cathode ray tube is divided into a plurality of cylindrical electrodes coaxially connected. An inner electrode is provided at the connection part between the cylindrical electrodes so that the center of an elliptical aperture of the inner electrode coincides with the center of an inner wall of the grid electrode. Thus, astigmatism in the main lens is removed, thereby improving the resolution of the color cathode ray tube.

Abstract: An electron gun for a cathode-ray tube has a structure in which the longitudinal middle portion of a focusing electrode is enlarged in diameter and an accelerating electrode is disposed in the enlarged-diameter portion of the focusing electrode. The opposite end portions of the focusing electrode are reduced in diameter, and the reduced-diameter portions of the focusing electrode and the accelerating electrode are secured to each other by means of electrode supporting rods.

Abstract: An electron gun for color-picture tube device comprises a final accelerating electrode and a focusing electrode divided into plural electrode units in the axial direction of the tube. A first focusing electrode unit adjacent to the final accelerating electrode is connected to a second focusing electrode unit adjacent to the first focusing electrode unit through a resistor. A focusing voltage being change in synchronous with the deflection of an electron beam is applied to the first focusing electrode unit. The resistor is used for removing the a.c. components from the focusing voltage. Then, the removed focusing voltage is applied to the second focusing electrode. For the electron beam deflected on the peripheral part of the screen, a quadrupole lens is formed. On the first focusing electrode unit side opposite to the second focusing electrode unit are formed first electron beam path holes whose major axes extend horizontally.

Abstract: In an electron gun assembly, three electron beams emitted from cathodes are passed through an electrode arrangement in which two intermediate electrodes are arranged between focusing are accelerating electrodes. A focusing voltage which is varied depending on an deflection of the electron beam is applied to the focusing electrode and an accelerating voltage is applied to the accelerating electrode. A resistor is connected between the accelerating electrode and the earth through a variable resistor and intermediate points of the resistor are connected to the intermediate electrodes. Thus, convergent and divergent lenses are formed between the focusing electrode and the intermediate electrode and between the accelerating electrode and the intermediate electrode. The lens powers of the convergent and divergent lenses are varied in accordance with the adjustment of the variable resistor.

Abstract: Disclosed is an electron gun for cathode ray tubes successively comprising an electron source electrode or cathode, a control or Wehnelt electrode, a first acceleration electrode or anode carried to an adjustable voltage and at least one focusing or second acceleration electrode in which there is inserted, between the first acceleration electrode and the focusing or second acceleration electrode, an additional electrode which is carried, during operation, to a fixed biase voltage, this electrode forming a low-powered electrostatic lens with the anode electrode and forming a high-powered electrostatic lens with the second acceleration electrode.

Abstract: A field emission type electron gun comprises a cathode, an anode placed opposing the cathode, a filament placed obliquely above the anode in a space between the cathode and anode to heat the anode, a control electrode and a vacuum container housing the cathode, the anode the control electrode and the filament. The anode has an elongated body with a through hole at its center, the control electrode is provided near the anode, and means for rendering the electric potential of the control electrode to be negative to the electric potential of the anode is provided to concentrate an electron beam to the top end of the anode.

Abstract: A monochrome cathode ray tube incorporates an electron gun featuring a focusing electrode having an upper cup-shaped portion comprising a top cylindrical sidewall portion and a lower inwardly tapering sidewall portion connecting to a flat bottom portion, the cup-shaped portion supported by an elongated cylindrical base portion having a diameter of from about 44 to 48 percent of the diameter of the upper cylindrical portion of the cup. The electron gun is particularly suitable for use in monochrome cathode ray tubes for projection color television.

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: A cathode ray tube apparatus comprises three cathodes arranged in line with each other in a first direction for emission of respective electron beams therefrom, a focusing electrode having first to third apertures defined therein for the passage of the respective electron beams therethrough, a quadrupole electrode structure including first to third quadrupole electrodes one for each electron beam, each of the quadrupole electrode being comprised of a pair of horizontal electrode pieces spaced a predetermined distance from each other in a second direction perpendicular to the first direction and positioned upwardly and downwardly, respectively, with respect to the associated electron beam, and a pair of vertical electrode pieces spaced a predetermined distance from each other in a direction aligned with the first direction and positioned leftwards and rightwards with respect to such associated electron beam, and a power source circuit for applying a predetermined voltage to the quadrupole electrode structure.

Abstract: In an electron gun assembly, three electron beams emitted from cathode are focused by focusing electrodes and directed to accelerating electrodes through intermediate electrode. Three electron beams are converged on a predetermined point near a screen by accelerating electrodes. The accelerating electrodes are supplied with a first potential and are connected to a ground through a resistor and a stem pin. The intermediate electrodes are connected to the resistor and are maintained at a second potential. The focusing electrodes are connected to another stem pin and supplied with a third potential through another stem pin so that the third potential can be independently adjusted.

Abstract: A particle shielding element of a shape memory metal is installed between an electroconductive layer on the inner peripheral surface of a neck glass tube of a cathode-ray tube and a shield cup of an electron gun therein to close a gap between the neck glass tube and the shield cup for thereby guarding the electronic gun against invasion of particles, Before the particle shielding element is inserted into the neck glass tube, the element is deformed to reduce its outer diameter so that the element can be inserted into the neck glass tube without scratching the electroconductive layer. After the element has been installed in Position in the neck glass tube, the temperature therein is adjusted to cause the element to recovery to its initial shape into dust sealing engagement with the electroconductive layer.

Abstract: An improved color display system includes a cathode-ray tube and a magnetic deflection yoke positioned on the tube. The tube includes an envelope having an inline electron gun for generating and directing three inline beams along initially coplanar paths toward a screen on an interior surface portion of the envelope. The gun includes a plurality of spaced electrodes which comprise three lenses. The first lens includes a beam-forming region for providing substantially symmetrical beams to a second lens. The second lens includes a first modulation electrode for providing asymmetrically-shaped beams to a third, or main, lens. At least one and preferably two dynamic voltage signals are applied to the modulation electrode of the second lens. Another dynamic voltage signal is applied to a second modulation electrode of the third lens. The voltage signals are related to the deflection of the beams and improve the electron beam spot size at the periphery of the tube screen.

Abstract: A flat thin display device is obtained by means of cold cathodes (10) in which each cathode provides the electron emission (14) for a (part of a) column of pixels. The emissive surface is preferably chosen to be parallel to the front and rear walls (3, 4) of the display device so that the cathodes cannot degrade due to an ion bombardment.

Abstract: An electron gun for color picture tube wherein a focusing electrode adjacent to an acceleration electrode supplied with highest voltage includes two members comprising a first member and a second member, wherein a platelike correction electrode extended into the inside of the first member through a single opening formed in an end face of the first member opposed to the second member is so disposed above and below electron beam passage holes formed in an end face of the second member located at the opposite side with respect to the accelerating electrode and opposed to the first member as to be electrically in contact with the second member, wherein constant voltage is applied to the first member, and wherein voltage so changed in synchronism with electron beam deflection as to have a value increased with increase in the amount of deflection is applied to the second member.

Abstract: In an electron gun apparatus for color cathode-ray tube, first and second focusing electrodes respectively for focusing electron beams emitted from three electron guns are disposed. Between the first and second focusing electrodes, a pair of third focusing electrodes for forming an axial-nonsymmetrical electron lens are also disposed. Mutually different dynamic voltages are supplied to the third focusing electrodes in accordance with the change in deflection angle of the electron beam. Owing to the above described structure, uniform resolution is obtained at both the central part and the peripheral part of the screen.

Abstract: A cathode ray tube having an electron gun with a triode section and bi-potential focusing lens electrodes. Generally such focusing lens electrodes comprise two juxtaposed cylindrical electrodes of which the one nearer the screen (accelerating electrode) is at the screen voltage of approximately 30 kV. If it is desired to increase the diameter of the focusing lens the voltage difference between the focusing electrode and the other cylindrical electrode (accelerating electrode) must be increased. The effect of this is to make the focusing electrode voltage unacceptably low with respect to the triode section. This problem is overcome by providing the accelerating electrode 29 with a diaphragm 30 having an aperture whose area is less than half the cross-sectional area of the focusing electrode (24).

Abstract: An electrode assembly for an electrostatic lens of the in-line type electron gun for a color cathode ray tube, includes a pair of tubular electrodes arranged in axially opposing relation. Each of the tubular electrodes includes a main tubular electrode member closed at its one end by an end wall which has an aperture of the configuration obtained by partially overlapping a plurality of circular openings arranged in an in-line manner. An auxiliary electrode member is fitted into the main electrode member. The auxiliary electrode member has an end wall positioned separately from the end wall of the main electrode member by a predetermined distance. The end wall of the auxiliary electrode member is formed with a plurality of independent collars projecting therethrough in parallel to the axial direction of the respective circular openings of the overlapped-multicircle aperture and to superpose the corresponding circular openings of the overlapped-multicircle aperture in an axial direction.

Abstract: A resistor assembly built into an electron tube, comprising a resistor element having at least one hole, an inner connector fitted in the hole, and an outer connector which formed integrally with the inner connector, or fixed thereto. The inner connector is electrically connected to the resistor element. The outer connector is secured and electrically connected to a part in the electron tube, whereby the resistor element is electrically connected to said part.

Abstract: The present invention provides an improvement in color cathode-ray tubes. Such tubes include an electron gun for generating and directing three inline beams, a center beam and two side beams, along initially coplanar paths toward a screen of the tube. The gun includes a plurality of spaced electrodes which provide a first, a second and a third lens for focusing the electron beams. The first lens has a beam forming region for providing substantially symmetrical beams to the second lens. The improvement comprises the combination of the second and third lens. The second lens includes at least one electrode to provide asymmetrically-shaped beams. The potentials applied to the second lens refract electron beams emerging off-axes from the first lens toward the axes. The third lens is a low aberration main focusing lens which provides asymmetrically-shaped beams of substantially constant current density to the screen.

Abstract: An electron gun employed in a color cathode ray tube, or the like, adapted, when electron beams are deflected in a convergence free deflecting magnetic field, to achieve optimal focused conditions for both the electron beam landing at the center and that landing at the corners of a screen by making, within a principal converging region for converging the electron beams, the converging angle in the vertical direction smaller than that in the horizontal direction and by forming, within an object point forming region, the object point in the vertical direction at a further position than where the object point in the horizontal direction is formed.

Abstract: A resistor is provided which comprises an insulation substrate, a resistive layer prepared from inorganic materials and printed on the insulation substrate, and an insulation layer prepared from borosilicate lead glass and overcoated on the resistive layer. The insulation layer contains an oxide of at least one transition metal selected from the group consisting of iron, nickel, chromium, cobalt, zinc, copper, zirconium, and cadmium. In the course of operation, the resistor of the present invention exhibits no changes in its resistance, irrespective of the length of time it may be operated.

Abstract: A color television display tube comprising an electron gun system (5) of the "in-line" type and an electromagnetic deflection unit. The end of the electron gun system is provided with field shapers comprising, for example, annular elements (34,34') of a material having a high magnetic permeability which are positioned around the two outer beams and are adapted to compensate coma. These elements are located in a more advanced position towards the screen than is usual, in positions where the outer beams have undergone a pre-deflection of at least 0.5 mm so as to reduce the "green droop" (anisotropic Y-coma) and to reduce the need for a negative 6-polefield.

Abstract: An electrostatic decelerating and scan expansion lens system (10) includes a mesh element (56) and operates in a cathode-ray tube (12) that incorporates a microchannel plate (24). The lens system is positioned downstream of the deflection structure (42 and 44) and provides linear magnification of the electron beam deflection angle. The mesh element is formed in the shape of a convex surface as viewed in the direction of travel of the electron beam (40) to provide a field with equipotential surfaces (100) of decreasing potential in the direction of electron beam travel. Secondary emission electrons generated by the mesh element as it intercepts the electron beam, are therefore, directed back toward the lens system and not toward the microchannel plate. Only the beam electrons strike the microchannel plate, which provides on the phosphorescent display (20) an image of high brightness, free from spurious light patterns.

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

Abstract: Color display tube comprising an electron gun 5 of the in-line type. The electron gun 5 comprises a main lens which is constituted by a first focussing electrode 25 and a second focussing electrode 26. The first focussing electrode comprises sub-electrodes 27, 28 placed at a distance from each other between which an auxiliary electrode constituting an astigmatic element G.sub.AST is positioned. The auxiliary electrode G.sub.AST is connected during operation to means for applying a constant voltage, whilst at least the sub-electrode 28 forming part of the main lens is connected during operation to means for applying a control voltage. The control voltage may be a static voltage or a dynamically varying voltage, for example, a parabolic voltage which is in synchronism with the line deflection.

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

Abstract: An electron gun for a high resolution color display tube comprises three inline cathode assemblies, a control grid with three inline apertures, a screen grid with three inline apertures, a screen grid slot plate with three inline substantially rectangular slots each associated with a different one of the apertures in the screen grid, and a main electron lens. The screen grid slot plate is attached to the screen grid on the side thereof facing the main electron lens. Each of the cathode assemblies produces an electron beam having a given beam current. Each of the slots in the screen grid slot plate has an inline dimension and a transverse dimension which are selected for the given beam current to independently control the horizontal and vertical sizes of the spot produced by each of the electron beams at a distance from the electron gun.

Abstract: A color display system includes a cathode-ray tube and self-converging yoke that produces an astigmatic magnetic deflection field within the tube. The tube has an electron gun for generating and directing three electron beams along paths toward a screen. The gun includes beam-forming region electrodes, main focusing lens electrodes, and two electrodes for forming a multipole lens between the beam-forming region and the main focusing lens in each of the electron beam paths. Each multipole lens is oriented to provide a correction to an associated electron beam to at least partially compensate for the effect of the astigmatic magnetic deflection field on that beam. A first multipole lens electrode is located between the beam-forming region electrodes and the main focusing lens electrodes. A second multipole electrode is connected to a main focusing lens electrode and located between the first multipole lens electrode and the main focusing lens, adjacent to the first multipole lens electrode.

Abstract: A color cathode ray tube apparatus having an electron gun assembly including a device for modulating a scanning velocity of electron beams at an auxiliary lens section for clarifying an image projected to a screen is disclosed. The color cathode ray tube apparatus comprises an enclosure having a panel section, a funnel section and a neck section, an electron gun assembly, including rear electrodes disposed in front of three cathodes for emitting electron beams, each having three through-holes for passing the beams for forming an auxiliary lens for preliminarily focusing the beams, and a front electrode located in front of the rear electrodes for forming a main lens in cooperation with one electrode thereof for further focusing the beams and converging the beams.

Abstract: An electron gun for producing and directing at least one electron beam along a beam path comprises a beam forming section and a main lens section for focusing the electron beam. The main lens section includes first and second electrodes arranged along the beam path and having an aperture through which the electron beam is passed, and at least one auxiliary electrode which is located between the first and second electrodes, the auxiliary electrode having an aperture through which the electron beam is passed. The aperture of the auxiliary electrode is greater than each of the apertures of the first and second electrodes. Different voltages are applied to the first and second electrodes, and the auxiliary electrode is supplied with a middle voltage intermediate between the two voltages applied to the first and second electrodes.

Abstract: A cathode-ray tube comprising in an evacuated envelope a diode electron gun for generating an electron beam. The electron gun includes a cathode arranged on an axis with its emissive surface extending substantially perpendicularly to the axis, and an anode extending substantially perpendicularly to the axis and having an aperture opposite to the cathode, the electron beam being focused on a target by means of at least one focusing lens. The cathode-ray tube is a picture display tube, the target is a display screen, and the spacing between the anode and the cathode of the diode electron gun is smaller than 200 .mu.m. The electron beam generated in the operating tube, viewed in the direction of propagation, is focused to form a cross-over immediately after the anode by a positive electron lens.

Abstract: An electron gun system providing beam convergence is disclosed for use in a color CRT display system. Means including cathode means develop three electron beams, two of which are off-axis with respect to a center axis of the gun. A plurality of electrodes means provide shaping and focusing, and assisting in the converging of the beams at the tube screen. Means are provided for developing and applying to the electrode means a pattern of potentials which form field components in the gaps therebetween; at least one of the electrode means receives a varying dynamic focusing voltage for dynamically focusing the beams as they are deflected across the screen. At least selected ones of the plurality of electrodes means for the off-axis beams are so structured and arranged as to cause a plurality of the field components to be asymmetric and effective to converge the off-axis beams. The strengths of the asymmetric field components vary in response to changes in the dynamic focus voltage.

Abstract: Color display tube comprising an electron gun 5 of the in-line type. The electron gun 5 comprises a main lens which is constituted by a first focussing electrode 25 and a second focussing electrode 26. The first focussing electrode comprises sub-electrodes 27, 28 placed at a distance from each other between which an auxiliary electrode constituting an astigmatic element G.sub.AST is positioned. The auxiiary electrode G.sub.AST is connected during operation to means for applying a constant voltage, whilst at least the sub-electrode 28 forming part of the main lens is connected during operation to means for applying a control voltage. The control voltage may be a static voltage or a dynamically varying voltage, for example, a parabolic voltage which is in synchronism with the line deflection.