Abstract: A color cathode ray tube includes a phosphor screen, cathodes, a G1 electrode, a G2 electrode, a G4 electrode, a G5 electrode and an anode for focusing the electron beams on the phosphor screen. The G5 electrode is divided into plural sub-electrodes arranged to be supplied alternately with a first focus voltage and a second focus voltage, at least one electrostatic quadrupole lens is formed between two of the sub-electrodes supplied with the first and second focus voltages, respectively, at least one lens for correcting curvature of the image field is formed between two of the sub-electrodes supplied with the first and second focus voltages, respectively. The G4 electrode, the G5 electrode and the phosphor screen satisfy following inequalities: 0.0625×L (mm)≦B−20A/(3&phgr;)≦22.

Abstract: A cathode-ray tube with high image quality in which electron beams with higher current density than the electron-emitting ability of cathodes are formed and a driving voltage of the cathodes can be decreased. A cathode-ray tube comprises a glass face-panel, a glass funnel connected to the rear part of the face-panel, and an electron gun for emitting electron beams that is contained in a neck portion of the funnel. On the peripheral surface of the funnel, a deflection yoke for deflecting the electron beams emitted from the electron gun is mounted. A phosphor dot for three colors of red, green and blue is applied on the inner surface of the face-panel, thus forming a phosphor screen surface. In the vicinity of the inner surface of the face-panel, a shadow mask is arranged substantially in parallel with the phosphor screen surface.

Abstract: A cathode ray tube includes a phosphor screen, an electron gun having a plurality of electrodes and a deflection device. Magnetic pieces attached to one of the electrodes and disposed in a magnetic deflection field generated by the deflection device are configured such that a magnetic field distribution having a region of a uniform magnetic field with an axial boundary thereof varying with a distance thereof from a tube axis is established to correct deflection defocusing.

Abstract: A color cathode ray tube equipped with an in-line electron gun for 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 and having therein a plate electrode with a beam passing area. The electrodes are given different voltages, wherein D and S have values in a region where all of the following inequalities are satisfied; S<D, and 145.5≦55S−20D S being a beam spacing in mm between central axes of the three adjacent electron beams at the main lens, and D being a dimension in mm related to a distance of a center of at least one of the in-line arrangement of the three electron beams to an inner edge of at least one of the two cylindrical electrodes.

Abstract: In an inline 3-beam system color cathode-ray tube, an inline 3-beam system color cathode-ray tube electron gun is able to uniformise shapes of beam spots of three electron beams on the right and left end portion of a fluorescent screen as much as possible.

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: An electron gun for a cathode ray tube includes a triode portion composed of a cathode, a first grid electrode and a second grid electrode. Each of the first and second grid electrodes has beam-guide holes. The beam-guide hole of the first grid electrode is larger than the beam-guide hole of the second grid electrode. The hole portion of the first grid electrode is thinner than the hole portion of the second grid electrode. The distance between the first grid electrode and the second grid electrode is two or three times greater than as the distance between the cathode and the first grid electrode.

Abstract: In a multi-stage, multi-beam electron gun of the common lens type for use in a color cathode ray tube (CRT), a charged grid in the prefocus lens of the electron gun is provided with three inline asymmetric beam passing apertures. The three asymmetric apertures may be either in the G4 grid, in the upper side of the G3 grid, or on the lower side of the G5 grid, i.e., in facing relation to the G4 grid, or may be incorporated in both the G3 and G5 grids. The small G3-G4 and G4-G5 spacing gives rise to isolation of the electron optic lenses of the two outer electron beams from that of the center electron beam allowing the asymmetric auxiliary apertures to asymmetrically and independently correct for electron beam astigmatism, i.e., the difference between the beam's horizontal and vertical focus voltage, and differences in the focus voltages of the two outer electron beams relative to the center electron beam.

Abstract: A color picture tube apparatus comprises auxiliary electrodes provided between first and second focusing electrodes, a nonaxisymmetric electrostatic lens is generated between the auxiliary electrodes and a focusing lens is generated between the first focusing electrode and the auxiliary electrode. A dynamic voltage V.sub.d is applied to the first and second focusing electrodes. Consequently, the effect of compensating the astigmatism of the electron beam caused by the deflection magnetic field and the defocus of the electron beam can be increased, the dynamic voltage can be decreased, and as a result, the cost of the circuit can be reduced. As the focusing function of the additional focusing lens is weakened and the electron beam trajectory is expanded, the magnification of the lens both at the center and the periphery of the screen can be equalized substantially and the uniformity of the focus of the electron beam between that at the center of the screen and that at the periphery of the screen becomes high.

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 ceramic substrate for mounting a field emission cathode is secured on the lower surface of a metal flange for assembly of an electron lens of a cathode ray tube, and the mounting position of the field emission cathode on the ceramic substrate is determined with reference to the metal flange.

Abstract: A electron gun includes three cathodes aligned in line, and a plurality of electrodes sequentially arranged from these cathodes in a direction in which the cathodes emit electron beams, wherein, of the plurality of electrodes, the facing portions of a convergence electrode and a final acceleration electrode forming a main lens are respectively constructed by cylindrical common peripheral rim electrodes long in the inline direction which form aperture holes common to the three electron beams, and the inner circumferential surface of the peripheral rim electrode of at least one of the convergence electrode and the final acceleration electrode has an almost polygonal shape with substantially six or more sides so as to correct any multipole lens components.

Abstract: In a cathode-ray tube, a nonmetallic material such as ceramic or the like is used for an electrode 1a part of an electron gun. Consequently, the deterioration of the efficiency of modulation of electron beam trajectories by an eddy current generated at the metallic electrode part of the electron gun in the high-frequency magnetic fields and the heat generation at the electrode can be decreased. The generation of the eddy current by high-frequency magnetic fields by a convergence yoke or the like can be restrained by using a nonmetallic material for the electrode part of the electron gun. Consequently, the efficiency of modulation of electron beam trajectories is not deteriorated also in a high-frequency modulation zone and the heat generation at the electrode part can be also restrained. Less deterioration of efficiency of modulation of electron beam trajectories by the alternating magnetic fields occurs even in the high-frequency modulation zone, for example, more than 100kHz.

Abstract: A color cathode ray tube includes an evacuated envelope having a panel portion with a phosphor screen formed on an inner surface thereof, a neck portion, and a funnel portion connecting the panel portion and the neck portion, and an electron gun housed in the neck portion. The electron gun has a cathode and a plurality of focus grid electrodes including grid electrodes for forming a multistage focus lens for focusing an electron beam emitted from the cathode. The cathode and the focus grid electrodes are fixed in predetermined axially spaced relationship by a pair of bead glass.

Abstract: A color cathode ray tube includes a three-beam in-line type electron gun. The main lens section includes a focus electrode and an anode facing the focus electrode, each of the focus electrode and the anode has an electrode having a single opening common for three electron beams in an end thereof facing each other and a plate electrode disposed therein and having beam apertures. The focus electrode and the anode satisfy a following inequality:(A+566)/106>H-2.times.Swhere A is V1.times.V2.times.T, V1 is a vertical diameter of the single opening, V2 is a vertical diameter of a center one of the beam apertures and T is an axial distance between the single opening and the plate electrode, H is a horizontal diameter of the single opening, S is P.times.

Abstract: A color cathode-ray tube which increases the degree of freedom in designing its main electron lens, decreases the electron beam spot diameter, and achieves high resolution, in which the between the focusing electrode (15) applied with the focusing voltage (Vf) and the anode electrode (17) applied with the anode voltage (Va), there is provided an intermediate electrode (16) applied with the potential Vm which is higher than the focusing voltage (Vf) and lower than the anode voltage (Va), and the focusing electrode (15). These voltages are set by a dividing resistor (30).

Abstract: A color cathode ray tube includes an electron gun for generating and focusing three in-line electron beams, and a pair of electrodes disposed down stream of a pre-focus lens and forming a final main lens. Each of the pair of electrodes have a common single opening for the three in-line electron beams in an end thereof opposing another of the pair of electrodes. A shield cup is fixed to a final electrode of the electron gun and has applied thereto the same potential which is applied the final electrode, the shield cup having a single aperture common to the three in-line electron beams. A focusing action of the pre-focus lens and a focusing action of the main lens are different between a center electron beam and a side electron beam of said three in-line electron beams, respectively.

Abstract: A color cathode ray tube includes an evacuated envelope formed of a panel portion having a phosphor screen, a neck portion and a funnel portion connecting the panel portion and the neck portion, and an in-line electron gun housed in the neck portion. The in-line electron gun includes a main lens and an electrostatic quadrupole lens. The focus electrode of the electron gun has a single opening at one end thereof for passing the three electron beams and opposes an anode to form a main lens therebetween. The single opening has a diameter larger in a horizontal direction than a diameter thereof 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 housing the in-line electron gun satisfies the following inequality: 23.2 mm.ltoreq.T.ltoreq.25.

Abstract: Focusing electrode in an electron gun for a color cathode ray tube, is disclosed, which can reduce a man-power and a number of components in a fabrication of the electron gun and can prevent a center electron beam from being elongated horizontally depending on a fitted depth of an inner guide electrode, the focusing electrode including a first focusing electrode adapted to be applied of a low static voltage and having a face with three vertically elongated electron beam pass-through holes of a key hole type and an inner guide electrode with three electron beam passthrough holes disposed at an inner side of the face, and a second focusing electrode adapted to be applied of a high dynamic voltage and having correcting electrodes unitary with a face of the second focusing electrode opposite to the first focusing electrode formed in a cathode direction at upper and lower sides of each of the three electron beam pass-through holes, whereby facilitating changes of center and side powers of the dynamic quadrupole le

Abstract: Electron gun for a color cathode ray tube, is disclosed, the color cathode ray tube having a plurality of cathodes for emitting electron beams, a first controlling electrode for controlling an amount of the electron beam emission, and an accelerating electrode for accelerating the electron beams, the electron gun including a power supplying part for examining a received video signal, determining a mode of the video signal, selecting a power of an appropriate level from a plurality of power levels according to a result of the determination, and supplying the selected power to the first controlling electrode and a second controlling electrode disposed between the cathodes and the first controlling electrode for controlling an emission radius of the electron beam according to the power of an appropriate level supplied to the first controlling electrode, thereby satisfying a high luminance as well as a high resolution requirements, whereby allowing processing of various modes of images with one electron gun and e

Abstract: A color cathode ray tube includes a phosphor screen, a shadow mask closely spaced from the phosphor screen and an electron gun. The electron gun includes three cathodes for emitting three in-line electron beams and a plurality of electrodes each having electron beam apertures for passing the electron beams, the electrodes are fixed in a predetermined axially spaced relationship on insulating supports, at least one of the electrodes is cup-shaped and has a correction plate electrode therein welded thereto, and edges of the correction plate electrode are formed with recesses and have sloped portions extending in a direction away from the recesses toward an inner wall of the electrode containing the correction plate electrode.

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

Abstract: A focusing electrode in an electron gun for a color cathode ray tube comprises: a first focusing electrode including one end with vertical plate electrodes projected toward cathodes in three vertically elongated electron beam through holes, and an inner electrode having three electron beam through holes disposed therein, adapted to be applied of a static voltage; and a second focusing electrode including horizontal plate electrodes respectively formed at upper and lower sides of three electron beam through holes inserted into the vertically elongated electron beam through holes in the first focussing electrode, adapted to be applied of a dynamic voltage synchronous to a deflection of the electron beams, wherein a dynamic quadrupole lens is formed among the vertical plate electrodes, the horizontal plate electrodes, and the inner electrode when applying the dynamic voltage to the second focusing electrode, and the intensity of the dynamic quadrupole lens can be controlled by controlling the depth of the inner

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 of focusing electrode (241), longer than the shape of the beam passing holes for the side electron beams.

Abstract: In order to increase the horizontal diameter of the lens and reduce the horizontal diameter of the peripheral spot for improving the resolution along the periphery of the phosphor screen of an in-line color picture tube, the focusing grids are so formed that the focusing force of the lens action on low voltage side is weaker in horizontal direction than in vertical direction and the diverging force of the lens action on high voltage side is weaker in horizontal direction than in vertical direction. As a result, the horizontal lens diameter increases, and the horizontal diameter of the peripheral spot is reduced even in the case where the laterally elongated distortion becomes conspicuous due to the increasing trend toward the flattening or the increased deflection angle of the panel.

Abstract: To correct a deterioration by a deflection aberration of an electron beam spot at a peripheral portion of an image plane and to promote the resolution, a cathode ray tube is proposed which is composed of an acceleration electrode 32 and a first kind and a second kind of focusing electrode group 311, 313, 312 and 314 which are applied with a first and a second focusing voltage, wherein a first electron lens in which a first focusing force for focusing the electron beam in the horizontal direction is always stronger than a second focusing force for focusing in the vertical direction, and a second electron lens wherein the focusing force for focusing the electron beam in the horizontal direction or in the vertical direction is stronger than the other depending on the relative sizes of a first focusing voltage applied on the first kind of focusing electrode group and a second focusing voltage applied on the second kind of focusing electrode group, are formed among the first kind and the second kind of electrode g

Abstract: A focus electrode of an electron gun for color cathode ray tubes of the present invention is divided into at least two focus electrodes, three electron beam passage apertures are provided on each focus electrode, electron beam passage apertures disposed on the one end sides of at least one focus electrodes have different astigmatism respectively from electron beam passage apertures disposed on the other end sides, electron beam passage apertures disposed on both sides of the focus electrode have different astigmatism from electron beam passage apertures disposed on both sides facing each other of the adjacent focus electrodes, the electron beam passage apertures disposed at the center of the respective focus electrodes are shielded. The invention provides an in-line three beam type electron gun for color cathode ray tubes which is capable of equalizing the beam spot configuration of three electron beams on the right and left ends of the fluorescent screen.

Abstract: An electron gun includes a cathode (K), a control electrode (1), an accelerating electrode (2), a first anode (3), a focus electrode (4), and a second anode (5), which electrodes are arranged in a tube axial direction at predetermined intervals; and electrode supports (11, 21, 31, 41, 51) provided to a side wall of each electrode and embedded in and secured to insulating supports (6); wherein the focus electrode (4) is cylindrical an has three different diameters respectively provided at a cathode side portion, an intermediate portion and a panel side portion, the panel side portion of the focus electrode (4) is inserted into the second anode (5) to constitute a main lens section, the inner diameter of the intermediate portion of the focus electrode (4) is smaller than the inner diameter of the panel side portion and larger than the inner diameter of the cathode side portion and the electrode support (41) is provided at the intermediate portion of the focus electrode (4).

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

Abstract: A color cathode ray tube includes a beam forming region, a main lens, a multipole lens and a lens for correction of curvature of the image field. The strength of the multiple lens for changing a cross-sectional shape of electron beams horizontally weakens in accordance with an increase of beam deflection. The lens for correction of curvature of the image filed changes trajectories of outer electron beams with respect to a enter electron beam in accordance with an increase of beam deflection.

Abstract: To propose a color cathode-ray tube which increases the degree of freedom in designing its main electron lens, decreases the electron beam spot diameter, and achieves high resolution, in which between the focusing electrode (15) applied with the focusing voltage (Vf) and the anode electrode (17) applied with the anode voltage (Va), there is provided the intermediate electrode (16) applied with the potential Vm which is higher than the focusing voltage (Vf) and lower than the anode voltage (Va), and the focusing electrode (15), the anode electrode (17) and the intermediate electrode (16) are respectively formed of cylindrical bodies each having an ellipse cross-section and closed by the electric field correcting electrode plates (25, 26, 27, 28) having three electron beam penetrating portions bored therethrough so as to be arrayed in an in-line fashion.

Abstract: An in-line electron gun includes a main lens having G3 and G4 three aperture electrodes and corresponding chain link (extended aperture) electrodes. The outer apertures in each of the G3 and G4 electrodes are barrel shaped and the middle aperture is elliptical. This construction maximizes the aperture area. The spacings between the G3 and G4 electrodes and their corresponding chain link electrodes are maximized within the existing size constraints of the gun. The combined effect weakens the electric field of the main lens which reduces spherical aberration.

Abstract: A color cathode ray tube includes an electron gun for generating and focusing three in-line electron beams, a deflection device for deflecting the three electron beams in the horizontal and vertical directions, and a phosphor screen which luminesces when the electron beams impinge thereon. A pair of electrodes of a plurality of electrodes form a final main lens between single openings provided in opposing ends of the pair of electrodes, each of the single openings being common to the three in-line electron beams, and a size of an aperture for a center electron beam of the three in-line electron beams in at least one of the first grid electrode and the second grid electrode is smaller than that of an aperture for a side electron beam of the three in-line electron beams in the at least one of the first grid electrode and the second grid electrode.

Abstract: A color cathode ray tube includes an electron gun having a plurality of electrodes, an electron beam deflection device and a phosphor screen. A deflection defocusing correcting element is located in a deflection magnetic field produced by the deflection device to locally modify the magnetic field in a path of an electron beam and corrects the deflection defocusing of the electron beam corresponding to deflection of the electron beam. The deflection defocusing element includes the magnetic metal plate providing magnetic pole pieces and a non-magnetic metal support for holding the magnetic metal plate in place. The magnetic metal plate and the non-magnetic metal support are laminated or clad one on another, or joined edge-to-edge.

Abstract: In order to provide a method of producing a cathode ray tube in a manner which well matches with a usual technique of producing a cathode ray tube by forming a spiral high-resistor on an inner face of a glass tube, in an electron gun of which a main focusing lens is configured by the spiral high-resistor, the step of fritting seal rings to both ends of the glass tube in which a hole is opened in the center portion; the step of applying a high-resistor paste to the glass tube, drying the paste, and then forming a spiral structure in the high-resistor film; the step of firing at 420 to 550 deg. C.; and the step of combining other electron gun parts to form the electron gun are included, and the spiral high-resistor is formed by a high-resistor paste in which ruthenium oxide is added to a glass material having a softening point that is lower than the annealing point of the glass tube.

Abstract: A cathode ray tube includes an electron gun having a plurality of electrodes, an electron beam deflection device and a phosphor screen. A method of correcting deflection defocusing in the cathode ray tube includes placement of pole pieces of magnetic material in a deflection magnetic field produced by the electron beam deflection device and thereby establishing a non-uniform magnetic field varying in synchronism with the deflection magnetic field in a path of an electron beam and correcting deflection defocusing of the electron beam corresponding to deflection of the electron beam in amount. The pole pieces are disposed within 50 mm from a magnetic core of the electron beam deflection device toward a cathode of the electron gun.

Abstract: An electron gun for a cathode ray tube includes an accelerating electrode to be supplied with a maximum voltage, a focus disposed adjacent to and spaced from the accelerating electrode, and a focus-corrective electrode adjacent to and spaced from the focus electrode. The accelerating electrode and the focus electrode form a first electron lens for focusing the electron beams stronger in a direction parallel to an in-line direction of the electron beams than in a direction perpendicular to the in-line direction, and the focus-corrective electrode is configured so as to form a quadrupole lens by application thereto of a voltage which is lower than a voltage applied to the focus electrode in cooperation with the focus electrode for elongating a cross-section of the electron beams horizontally, and is adapted to be supplied with a voltage which increases with increasing deflection of the electron beams and which is lower than the voltage applied to the focus electrode.

Abstract: In a focusing electrode system in an electron gun for a color cathode ray tube, distortion of an electron beam, that takes place when horizontal and vertical diameters of a main focusing lens are different is corrected by adjusting power of a dynamic four polar lens. The system includes a first focusing electrode adapted to have applied a static voltage, and a second focusing electrode adapted to have applied a dynamic voltage synchronous to a deflection of electron beams. The second focusing electrode includes, one end having a burring part on a circumference of each of three electron beam pass-through holes at upper and lower portions thereof. A size of the burring part of the electron beam pass-through hole at a center thereof is different from a size of the burring part on each of the electron beam pass-through holes at outer portions thereof.

Abstract: A focusing electrode in an electron gun for a color cathode ray tube or high definition industrial picture tube includes a first and second focusing electrodes. A recess portion in one end of the first focusing electrode is oriented to face burring parts of the second focusing electrode. An electron beam and a surrounding portion pass through holes in the first focusing electrode to reduce the space between the first and second focusing electrodes. This improves the static convergence drift.

Abstract: An electron gun comprises a supplementary grid applied with a voltage which dynamically changes in synchronization with a magnetic field generated by a deflection yoke, between a second grid and a third grid. Further, by the second grid, the supplementary grid, and the third grid, an electron is constructed which has an astigmatic aberration in which a focusing force in the horizontal direction is stronger than a focusing force in the vertical direction. The intensity of the astigmatic aberration of the electron lens is dynamically changed by a voltage applied to the supplementary grid.

Abstract: A pre-focus electrode system in an electron gun for a color cathode ray tubes disclosed, the color cathode ray tube including, in successive arrangement, a three electrode part having a plurality of cathodes each for emitting electron beams, a control electrode for controlling emission of the electron beams, an accelerating electrode for accelerating the electron beams, at least two pre-focus electrodes for pre-focusing the electron beams, and a focusing electrode and an anode for forming a main lens for focusing the electron beams on a screen. The focusing electrode has two electrodes provided by dividing the focusing electrode into two to form a first dynamic four polar lens part with one of the two electrode applied of a static voltage and the other electrode applied of a dynamic voltage synchronous to a deflection current.

Abstract: An electron gun for a color cathode ray tube includes cathode, control and screen electrodes, forming a triode. The electron gun includes first, second and third focus electrodes, forming main and auxiliary lenses. A final accelerating electrode faces the third focus electrode. A static voltage is applied to the screen electrode and the second focus electrode. A dynamic focus voltage is applied to the first and third focus electrodes. First and second quadrupole lenses are formed.

Abstract: A CRT system is provided, preventing the resolution on a phosphor screen from degrading due to the characteristic or performance variation and/or deviation of an electron gun. The electron gun has cathodes for emitting R, G, and B electron beams. First and second focusing electrodes focus the electron beams onto a phosphor screen. A drive unit has a power supply for supplying first and second focusing voltages to the first and second focusing electrodes, respectively. The second focusing voltage is an ac voltage with a parabolic waveform. The first focusing voltage is a dc voltage generated by dividing the second focusing voltage with the use of a resistor. A difference between the first and second focusing voltages generates an electrostatic quadruple lens in a space between the first and second focusing electrodes.

Abstract: An electron gun for a color cathode ray tube includes a triode having a cathode, a control electrode, and a screen electrode for producing electron beams; first, second, and third focus electrodes; and a final accelerating electrode sequentially disposed from the screen electrode. A first constant voltage is applied to the screen electrode and the second focus electrode, a second constant voltage higher than the first constant voltage is applied to the first focus electrode and the third focus electrode, and an anode voltage higher than the second constant voltage is applied to the final accelerating electrode, so that electron beams cross from the triode cross between a main lens formed by the third focus electrode and the final accelerating electrode, and an auxiliary lens formed by the first, second, and third focus electrodes. The electron gun produces uniform size electron beam spots over a fluorescent film of a cathode ray tube with reduced spherical aberration.

Abstract: A color cathode ray tube of the in-line type has a pre-focusing lens part and a main lens part. The prefocusing lens part comprises a first (G1) and a second (G2) electrode, each having apertures for passing electron beams. The apertures in the second electrode comprise a first (G2A) and a second (G2B) aperture, each being substantially stigmatic. The diameters of the apertures are different and 1.5.ltoreq..O slashed.G2B/.O slashed.G2A.ltoreq.5.

Abstract: A field emitter for producing an electron beam includes at least one cold cathode unit. Each of the cold cathode units includes an emitter cone having an emitter tip and a gate spaced apart from the emitter tip for extracting electrons from the emitter tip in a propagation direction upon application of a positive dc voltage on the gate with respect to the emitter tip. The gate forms a gate cavity for propagation of the extracted electrons therethrough. Each of the cold cathode units further includes at least one lens electrode disposed further in the propagation direction from the emitter tip than the gate, the at least one lens electrode forming at least one lens cavity for propagation of the extracted electrons therethrough. The at least one lens electrode is for focusing the extracted electrons in part of the gate cavity, part of the at least one lens cavity, and part of the region therebetween.

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

Abstract: A color cathode ray tube has a phosphor screen and an in-line electron gun. Each of the focus electrode and the anode of has a single opening for passing three electron beams. The single opening has a diameter larger in a horizontal direction than a diameter thereof in a vertical direction. Each of the focus electrode and the anode has a plate electrode placed therein and forming apertures for passing the three electron beams respectively. The focus electrode and the anode forms a main lens therebetween. The distance from the main lens to the phosphor screen is 360 mm or less, the outside diameter T in mm of the neck portion of the evacuated envelope housing the electron gun satisfies 23.5 mm.ltoreq.T.ltoreq.25.3 mm, the value D in mm of twice the distance from the center of a trajectory of a side electron beam to a vertical edge of the single opening in each of the focus electrode and the anode satisfies 6.5 mm<D.ltoreq.8.

Abstract: An electron gun for a color cathode ray tube includes a cathode, a triode portion having control and accelerating electrodes, a pre-focus lens formed by a first accelerating/focusing electrode, a second accelerating/focusing electrode, and a third accelerating/focusing electrode, and a main lens formed by the third accelerating/focusing electrode and a fourth accelerating/focusing electrode, wherein outer lens elements of the pre-focus lens and the main lens are inclined so as to prevent formation of halos.

Abstract: A color display system includes a color cathode ray tube having an electron gun having at least a cathode, a control electrode, an accelerating electrode, a focus electrode and an anode. The focus electrode includes a first focus electrode, a second focus electrode and a third focus electrode. The first focus electrode faces the accelerating electrode, a first quadrupole lens is formed in at least one of opposing ends of the first and second focus electrodes.