Abstract: An electron gun (1) for use in a cathode ray tube has brackets (20) connecting grids (2, 3, 4, 5, 6) to insulator rods (10). Electric conductors (11) extending to contact pins (12) embedded in a glass flange (13) are welded to a base (21) of the brackets (20). Legs (25) extend from the base (21) and are welded to the grids (2, 3, 4, 5, 6). Lugs (26) extend from the base (21) in opposite directions and are embedded in the glass rods (10). The brackets (20) provides stability to the grids (2, 3, 4, 5, 6), thereby preventing varying properties of guns (1) from one batch. The cathode ray tube is provided with the gun (1).

Abstract: A color cathode ray tube having an improved electron gun, includes a quadrupole lens consisting of an independent static electrode having a static voltage applied thereto and a dynamic electrode which is disposed opposite to the independent electrode and having a dynamic voltage applied thereto. A dynamic strong quadrupole lens effect is obtained by applying a modulation voltage or parabola voltage to the dynamic electrode. When electron-beam-passing-apertures in electrodes of a main lens are enlarged, each axial distance between the axes of three electron-beam-passing-apertures of the static electrode opposite to the dynamic electrode in the strong quadrupole lens forming electrodes is offset and the sizes of the opposite side electron-beam-passing-apertures are increased by the offset axial distance.

Abstract: A cathode-ray tube includes a plate having a first hole on a first surface of the plate and a second hole on a second surface of the plate. The first and second holes coupled together to allow electron beams to pass therethrough. The plate is a unitary structure. The first hole is formed by initiating a first hole formation from the first surface, and the second hole is formed by initiating a second hole formation from the second surface. The first surface is on an opposing side of the second surface.

Abstract: The invention relates to a cathode ray tube (100) comprising an electron source (101) having a cathode (105, 106, 107) for emitting electrons, an electron beam guidance cavity (120, 121, 122) having an input and an output aperture for concentrating electrons emitted from the cathode, a first electrode being connectable to a first power supply means for applying, in operation, an electric field having a first field strength E1 between the cathode (105, 106, 107) and the output aperture so as to allow electron transport through said electron beam guidance cavity (120, 121, 122), an accelerating grid (140) unit for accelerating the electrons leaving said cavity, and a main electron lens (150) for focusing the accelerated electrons on a display screen (170). According to the invention, said accelerating grid unit (140) further comprises a plurality of grids (G3, G4, G5) together constituting a pre-focus lens.

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: A 90 percent electron gun aperture astigmatism is used in conjunction with a four-pole electromagnet to make a CRT electron beam just focus point and minimum beam width occur closer to the same focus voltage. A single grid may have the 90 percent astigmatism, or astigmatisms in two or more grids may combine to produce an effective 90 percent astigmatism. A four-pole electromagnet is positioned around the focusing grid and current driving the electromagnet is varied with beam position during normal operation.

Abstract: The screen electrode in an electron gun for use in a cathode ray tube has multi-stage apertures such that the entrance area of an aperture is larger than the exit area. This has an effect of smaller screen electrode apertures with a result of increased pre-focusing of electron beams passing through the apertures. Thus, increased pre-focusing reduces the beam incident angle to the main lens. A smaller beam incident angle generates less spherical aberration in the main lens.

Abstract: The present invention provides a color cathode ray tube which can improve the focusing characteristics in a wide range of a phosphor screen by setting the total length of a focus electrode divided in multi-stages within a given value and properly selecting the mounting position and the sensitivity of an electrostatic quadrupole lens. A focus electrode G5 which constitutes a final-stage main lens includes a plurality of electrode members G5-1, G5-2, G5-3, G5-4 which constitute an electrostatic quadrupole lens and a curvature-of-image-field correction lens, and assuming the distance from a surface of the focus electrode G5 which faces an anode G6 in an opposed manner to the final-stage main lens-side position of the electrostatic quadrupole lens as L2, a relationship of 7.55≦L2≦11.5 is set.

Abstract: An inline electron gun and a color cathode ray tube provided with the inline electron gun for reducing the manufacturing cost for an assembly jig of the electron gun, for example, that might be generated with a change in the size of the cathode ray tube and for realizing a favorable static convergence property is provided. The inline gun includes a first flat plate electrode, a second flat plate electrode, two cylindrical electrodes at least is used. An opening geometry of outer passage holes provided in the first flat plate electrode and the second flat plate electrode is configured by combining an inner curve and an outer curve, which have different degrees. The opening geometries of the outer passage holes are symmetric with respect to a line. At least one of the outer curves and the inner curves in the outer passage holes have different degrees.

Abstract: Electron gun in a color CRT including a controlling electrode and an accelerating electrode each having a distance S0 between a central electron beam pass through hole and an outer electron beam pass through hole for passing electron beams emitted from cathodes, a pre-focusing electrode having a distance S1 between a central electron beam pass through hole and an outer electron beam pass through hole, a focusing electrode and an anode each having a rim at an opposite part for forming single electron beam pass through hole and an electrostatic field controlling body inside of the rim, for forming a large sized main focusing electrostatic lens by a potential difference, and diverging means for diverging the outer electron beams incident on the focusing electrode from the pre-focusing electrode outwardly with respect to the central electron beam, wherein a ratio WS/H of a sum WS of a horizontal diameter of the central electron beam pass through hole of the electrostatic field controlling body and a minimum width

Abstract: The present invention provides a flat-panel type color cathode ray tube which has the favorable focusing characteristics and can shorten the total length thereof. The color cathode ray tube includes an evacuated envelope which is constituted of a panel 1 which has a diagonal effective diameter of approximately 51 cm, a neck 3 which houses an electron gun 10 and a funnel 3 which connects the panel and the neck. The electron gun 10 includes a cathode, a first electrode, a second electrode, a focusing electrode and an anode electrode. Assuming the equivalent radius of curvature in the X direction of an inner surface of the panel 1 as Rix and the equivalent radius of curvature in the Y direction of an inner surface of the panel 1 as Riy, the distance Lm between the cathode and a screen-side end portion of the focusing electrode is set to 37 mm≦Lm≦45 mm.

Abstract: Among a plurality of electrodes composing an electron gun, at least one electrode is separated into two along a plane substantially perpendicular to a central axis, the two being a first cylindrical electrode and a second cylindrical electrode. Between the two electrodes, a connecting member in an approximate cylindrical shape having a slit is interposed, which electrically connects the first and second cylindrical electrodes with each other. The first and second cylindrical electrodes are fixed to a support rod via the connecting member and support portions provided on a side of the connecting member. Since a modulation magnetic field from outside a cathode-ray tube passes through the slit, eddy current loss can be reduced, whereby a desired electron beam modulation effect can be achieved.

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 color cathode ray tube includes an electron gun having an electron beam generating portion arrayed in a horizontal direction for generating three electron beams, and a main lens for focusing the three electron beams upon a fluorescent face, and a deflection yoke for scanning the three electron beams. The main lens has electrodes with three electron beams passages including a central electron beam passage and side electron beam passages. The main lens includes an accelerating electrode supplied with an accelerating voltage, a first focusing electrode supplied with a first focusing voltage, and a second focusing electrode supplied with a second focusing voltage. An axially asymmetric electron lens is formed between the first focusing electrode and the second focusing electrode.

Abstract: A dynamic focus electron gun for a color cathode ray tube including a cathode, a control electrode and a screen electrode, which constitute a triode, a first focusing electrode having three vertically elongated electron beam through-holes formed through its emitting surface, a second focusing electrode which constitutes a quadrupole lens together with the first focusing electrode and having three circular electron beam through-holes formed through its entering surface facing the emitting surface of the first focusing electrode, and a final accelerating electrode installed adjacent to the second focusing electrode and constituting a main electronic lens together with the second focusing electrode.

Abstract: Each of an anode and one of the sub-electrodes of a main lens of a shadow mask color cathode ray tube includes a first member having a single opening in their facing ends, and a second member having three beam apertures, wherein (A+566)/106>H−2×S is satisfied, where A is V1×V2×T, V1 is a vertical diameter of the opening, V2 is a vertical diameter of the center beam aperture, T is a distance between the opening and the second electrode member, H is a horizontal diameter of the opening, S is P×L/Q, where P is a horizontal center-to-center spacing between adjacent phosphor elements, Q is a spacing between the phosphor screen and the shadow mask, and L is a distance between the shadow mask and the opening in the first member.

Abstract: An in-line gun for a cathode ray tube includes three beam-passing holes formed in an electrode and at least two reference holes formed in the electrode. The three beam-passing holes are aligned in line. The two reference holes are positioned opposite to each other with respect to a middle beam-passing hole in the three beams-passing holes. The two reference holes are of different shapes. One of the two reference holes is a round hole and the other is an elongated hole. The elongated hole is formed by elongating a hole having a center located at a position opposite to that of the round hole toward the middle beam-passing hole. The elongated hole may be defined by combining a small-diameter hole, a large-diameter hole, and two lines tangent to the small-diameter hole and the large-diameter hole. The large-diameter hole is closer to the middle beam-passing hole than the small-diameter hole.

Abstract: An electron gun for a color cathode ray tube includes a first electrode, a second electrode and a third electrode. A waveform alternating voltage or a static voltage is applied to the first electrode in which three vertical slot type electron beam passing holes are formed. The second electrode is installed at one side of the first electrode in which circular electron beam passing holes are formed. The third electrode is disposed at the other side of the first electrode. A single horizontal slot type electron beam passing hole is formed in the third electrode to which the same dynamic focus voltage as that in the second electrode is applied.

Abstract: A color cathode ray tube has excellent focusing characteristics over the whole screen thereof, as well as a total length which is short, thus providing a compact monitoring device. The Cathode ray tube has an electron gun in which the ratio between the diagonal size De of a phosphor screen and the distance Lg from the center of the phosphor screen to an end portion of a focusing electrode which forms a main lens portion of the electron gun and faces an anode electrode in an opposed manner is set to De/Lg>1.5. The focusing electrode and the anode electrode have single opening portions whose opening size in the horizontal direction is not less than 68% of the outer diameter of a neck portion and end surfaces of the opening portions face each other in an opposed manner in the tube axis direction along which the electron beams pass.

Abstract: An electron gun for a cathode ray tube includes a cathode for radiating thermal electrons, control and screen electrodes disposed away from the cathode at a predetermined distance in respective order, a focus electrode disposed away from the screen electrode, the focus electrode having upper and lower cylinders and an inclined portion disposed between the upper and lower cylinders, and an anode electrode formed in a cylindrical shape, the upper cylinder, the inclined portion, and a part of the lower cylinder are disposed in the anode electrode. A length S1 of the upper cylinder in a direction of a tube axis is less than a length T1 of the inclined portion.

Abstract: An electric field expansion type main lens portion is constituted by including a focus electrode to which a focus voltage on a first level is applied, an anode electrode to which an anode voltage on a second level higher than the first level is applied, and two auxiliary electrodes to which a voltage on a third level higher than the first level and lower than the second level is applied and which are arranged between the focus electrode and the anode electrode. An electrode length of each of the two auxiliary electrodes along an electron beam traveling direction is constituted so as to differ in accordance with a difference in potential between electrodes arranged at front and rear positions in the electron beam traveling direction of each auxiliary electrode.

Abstract: A dynamic focus electrode has a vibration-damping portion formed by a beading process at a peripheral portion of an electron beam passage hole thereof, a plate face thereof, or an embedment portion thereof. Thereby, vibration of the dynamic focus electrode is suppressed.

Abstract: An electron gun structure includes a first non-axial-symmetrical lens portion which is arranged in the vicinity of an electron beam formation portion, and a second non-axial-symmetrical lens portion formed to a main lens portion, the first non-axial symmetrical lens portion has a lens action in the vertical direction that a focusing action relative to the electron beams becomes stronger as a quantity of deflection of the electron beams increases, and a lens action in the horizontal direction which substantially rarely acts on the electron beams, and a comprehensive lens system of the second non-axial-symmetrical lens portion and the main lens portion has a lens action in the vertical direction that a divergence action relative to the electron beams becomes stronger as a quantity of deflection of the electron beams increases, and a lens action in the horizontal direction which substantially rarely acts on the electron beams.

Abstract: A color display device with an improved focus performance. Conventional color display tubes with DAF have an electron gun with a second focusing electrode (25) driven with a dynamic voltage which is varied synchronously with the deflection field. The dynamic quadruple lens formed between the first focusing electrode (23) and the second focusing electrode (25) is designed such that the horizontal lens action, which arises when the voltage on the second focusing electrode is increased, should be compensated by the main lens which becomes weaker when the voltage on the second focusing electrode is increased. In practice, this is not possible in the required range of the dynamic voltage on the second focusing electrode, leading to a deterioration of the focus performance of the color display device.

Abstract: An electron gun for a cathode ray tube includes a cathode for radiating electron beams, a scanning velocity modulation coil for synchronizing the electron beams with an image signal, a focus electrode having first and second sub-electrodes disposed with a gap through which a magnetic field generated by the scanning velocity modulation coil passes, a plurality of grid electrodes with the focus electrode for controlling the electron beams radiated from the cathode, a support for aligning and supporting the grid electrodes, and a shield electrode electrically connected to the first and second sub-electrodes to protect against infiltration of an outer electric field. The shield electrode includes plural intermediate electrodes disposed in the gap between the first and second sub-electrodes, and electrical connecting unit for electrically connecting the intermediate electrodes to the first and second sub-electrodes. The intermediate electrodes are spaced away from each other.

Abstract: Disclosed is an electron gun assembly for a cathode ray tube comprising a single cathode for emitting electrons; a first electrode and a second electrode mounted in this order from the cathode in the direction the electrons are emitted, the cathode and the first and second electrodes forming a triode portion; a plurality of focusing electrodes mounted one after the other away from the second electrode in the direction the electrons are emitted; an anode electrode mounted away from the furthermost focusing electrode in the direction the thermions are emitted; and a support for providing support to the above elements in the mounting sequence as described, wherein the first and second electrodes include a plurality of beam passage apertures, which are aligned on each the first and second electrodes in a direction perpendicular to a direction at which an electron beam is scanned.

Abstract: An electrode of an electron gun, and an electron gun for a cathode ray tube are provided. The electron gun includes an outer-rim electrode having a large-diameter electron beam passing hole through which three electron beams pass, and an inner electrode installed inside the outer-rim electrode member, and having three electron beam passing holes disposed in an in-line arrangement and recesses formed at peripheries of the electron beam passing holes, the recesses having an eccentricity distance larger than an eccentricity distance between centers of the three electron beam passing holes.

Abstract: The electron gun of a cathode ray tube comprises a main electron lens portion consisting of at least four electrodes arranged in the order of first grid (5), second grid (6), third grid (7) and fourth grid (8). An intermediate first voltage and an anode voltage are applied to the first grid (5) and the fourth grid (8), respectively. A resistor (100) is connected at one end to the second grid (6) and at the other end to the third grid (7) positioned adjacent to the second grid, with the result that second and third voltages of substantially the same potential, which are intermediate between the first voltage and the anode voltage, are applied to the second grid and the third grid, respectively. These grids are arranged such that a second electrostatic capacitance between the second and third grids (6, 7) is smaller than any of a first electrostatic capacitance between the first and second grids (5, 6) and a third electrostatic capacitance between the third and fourth grids (7, 8).

Abstract: An electron gun for a color CRT includes a triode unit including a cathode, a control electrode, and a screen electrode for emitting an electron beam, first and second auxiliary focusing electrodes sequentially installed coaxially with the triode unit, for forming auxiliary lenses, first and second focusing electrodes installed coaxially with the first and second electrodes, for forming a quadrupole lens, and a final acceleration electrode installed close to the second focusing electrode, for forming a main lens. In the electron gun, protruding portions having flat surfaces corresponding to opposite surfaces of the first and second focusing electrodes are formed on at least one of the opposite surfaces of the first and second focusing electrodes to change the profile of the electron beam by applying a dynamic focus voltage to the edge of electron beam passing holes formed in the opposite surfaces.

Abstract: A color cathode ray tube includes an electron gun having cathode structures arrayed in line with a cup-shaped first grid electrode. Each of the cathode structures is fused and fixed to a cathode in an electrically insulated state by hermetic glass. A cathode support to which the cathode structures are fixed by glass is fixedly housed in the cup-shaped first grid electrode, and the first grid electrode and the cathode support are welded on an axis along which the cathode structures are arrayed. The cathode structures and the first grid electrode are welded on an inline axis so that the thermal deformation of the cathode support can be made uniform at the center portion and at side portions. Accordingly, at the start-up time of the color cathode ray tube, the cathode currents at the center portion and at the side portions can be equalized and a good color balance can be maintained on the screen.

Abstract: A cathode ray tube has a phosphor screen and an electron gun. The electron gun includes an electron beam generating section and an electron beam focusing section for focusing an electron beam from the electron beam generating section onto the phosphor screen. The electron beam generating section and the electron beam focusing section are mounted in predetermined spaced relationship on plural insulator support rods. The electron beam focusing section includes at least one compound electrode formed of a first electrode member, a second electrode member and a plate-like electrode member sandwiched therebetween. The plate-like electrode member is fabricated from a material thicker than materials from which the first and second electrode members are fabricated. The plate-like electrode member is laser-welded to the first and second electrode members at points of edges of the first and second electrode members.

Abstract: A sixth grid, which is part of a main electron lens section, is made up of a first anode, an auxiliary electrode and a second anode. A fifth grid is applied with an intermediate voltage. The first and second anodes are applied with an anode voltage. An intermediate electrode and the auxiliary electrode are applied with a voltage whose level is between the levels of the intermediate voltage and anode voltage.

Abstract: A color cathode ray tube includes third, fourth and fifth electrodes and an anode in its electron beam focusing section.

Abstract: In a cathode ray tube device including an electron gun (4) inside a neck portion (3) of a funnel (2), a deflection yoke (5) having horizontal deflection coils (61) and vertical deflection coils (52) on an outer surface of the funnel (2) and on the side of a front panel with respect to the electron gun (4), and velocity modulation coils (6) on an outer surface of the neck portion (3), the velocity modulation coils are provided so that an end of the velocity modulation coil (6) on the side of the front panel is positioned on the side of the electron gun (4) with respect to an end of the horizontal deflection coil (51) on the side of the electron gun (4) and is positioned on the side of the front panel with respect to an end of the electron gun (4) on the side of the front panel.

Abstract: The cathode ray tube apparatus comprises a main lens constructed by focus, intermediate, and final acceleration electrodes. The main lens includes a focusing area positioned in a side of the focus electrode, and a diverging area positioned in a side of the final acceleration electrode. A focusing force curve expressing the focusing force along the tube-axis direction in the focusing area has two convex parts respectively being at first and second levels, and a concave part provided between the convex parts and being at a third level sufficiently lower than the first and second levels. The third level is set to a lowermost level at which a focusing or diverging force is not substantially effected on the electron beam. An intermediate electrode having a non-circular shaped hole is positioned near an area of the lowermost level.

Abstract: A method of manufacturing an electron gun (10) for use in a color display tube (1) is described. The electron gun (10) is provided with an additional electrode (44), positioned between the anode electrode (21a) and the centering cup (23). This additional electrode (44) is part of the beaded unit (29) of the electron gun (10), and this enables very accurate positioning of this additional electrode (44) with regard to its distance to the main focusing section (21) as well as its rotation. This makes it possible to use this additional electrode (44) to improve the quality of the main focusing section (21) by considering it as an integral part of the main focusing section (21). For this reason this additional electrode is referred to as Main lens Field Modifier (MFM) (44).

Abstract: An electron gun for a color cathode ray tube includes cathodes, a control electrode, and a screen electrode, forming a triode, first, second, third, and fourth focusing electrodes, sequentially arranged relative to the screen electrode and forming at least one first quadrupole lens, fifth and sixth focusing electrodes, adjacent to the fourth focusing electrode and forming at least one second quadrupole lens, and a final accelerating electrode, adjacent to the sixth focusing electrode and forming a main lens.

Abstract: A solid dielectric material is installed between the second focus electrode and third focus electrode in a one-pin dynamic electron gun assembly in order to increase capacitance between the two electrodes. The increased capacitance between the two electrodes reduces the voltage Vg between the two electrodes and increases the effective voltage Vd (eff) between the third focus electrode and the fourth focus electrode since Vd=Vg+Vd (eff).

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: 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 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: A color cathode ray tube includes an evacuated envelope formed of a panel portion having a phosphor screen on an inner surface thereof and housing a shadow mask, 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, a vertical mask aperture pitch on a vertical center line of the shadow mask is not larger than 0.28 mm at a center of the shadow mask, and an outer diameter T of the neck portion housing the in-line electron gun satisfies the following inequality 23.2 mm≦T≦25.

Abstract: An electron gun for a color cathode ray tube including a triode consisting of a cathode, a control electrode and a screen electrode, and first and second focus electrodes facing each other and installed sequentially from the triode, for forming quadrupole lenses for focusing and accelerating an electron beam emitted from the triode, wherein three first-elongated electron beam passing holes slanting in one direction at a predetermined angle with respect to the longitudinal axis are formed on the facing surface of the first focus electrode, and three second-elongated electron beam passing holes slanting in a direction opposite to that of the first-elongated electron beam passing holes at a predetermined angle with respect to the longitudinal axis are formed on the facing surface of the second focus electrode, and wherein a dynamic focus voltage synchronized with a deflection signal is applied to the first focus electrode and a focus voltage is applied to the second focus electrode.

Abstract: A cathode ray tube includes an electron gun having a cathode, first and second grid electrodes, plural focus electrodes and an anode electrode fixed by two glass beads; a voltage-dividing resistor attached to one glass bead for producing an intermediate voltage applied to a first one of the plural focus electrodes adjacent to the anode electrode by dividing an anode voltage and a metal conductor attached to one of electrodes of the electron gun disposed upstream of the first one of the plural focus electrodes to surround the voltage-dividing resistor and the glass bead. The voltage-dividing resistor includes an overcoat insulating film, a resistance element and an insulating substrate stacked in the order named from the overcoat insulating film facing the glass bead, and the resistance element includes first-type resistance-forming regions disposed on opposite sides of the metal conductor and a second-type resistance-forming region containing a portion thereof facing the metal conductor.

Abstract: An electrode of an electron gun, and an electron gun for a cathode ray tube are provided. The electron gun includes a first electrode member having supporting portions protruding from both edges thereof along a lengthwise direction, and three connection holes disposed in an in-line arrangement, and second electrode members connected to the connection holes of the first electrode member, and each having a plane portion where electron beam passing holes are formed, and a flange portion formed along the periphery of the plane portion and connected to the periphery of each connection hole of the first electrode member.

Abstract: A color cathode ray tube includes a three-color phosphor screen, a shadow mask spaced from the phosphor screen and a three-beam 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. The focus electrode is formed of at least one first sub-electrode adapted to be supplied with a first focus voltage and at least one second sub-electrode adapted to be supplied with a second focus voltage, one of the at least one first sub-electrode and the at least one second sub-electrode faces the anode. The second focus voltage is a fixed voltage superposed with a dynamic voltage varying with beam deflection, and an electrostatic quadrupole lens is formed between a first one of the at least one first sub-electrode and a first one of the at least one second sub-electrode.

Abstract: An in-line three beam electron gun for a color cathode ray tube comprising a cathode for emitting electron beams, a control electrode and a screen electrode, first through fourth focusing electrodes and an accelerating electrode, wherein the third focusing electrode has vertically elongated electron beam apertures to form a quadrupole lens, and the fourth focusing electrode has circular electron beam apertures. A first uni-potential lens is formed between the first and second focusing electrodes, a second uni-potential lens is formed between the second and third focusing electrodes, a quadrupole lens is formed between the third and fourth focusing electrodes and a main leans is formed between the fourth electrode and the accelerating electrode, when a static voltage is applied to the first and second focusing electrodes and a dynamic focusing voltage synchronous to a deflection signal is applied to the third and fourth focusing electrodes.

Abstract: A display device comprising a deflection unit and a cathode ray tube having an in-line electron gun. The electron gun comprises a main lens portion having means for generating a main lens field and an auxiliary field. Furthermore, the electron gun comprises a prefocusing lens portion having a first, a second and a third electrode for generating a prefocusing lens field. In operation, in a direction perpendicular to the in-line plane, the auxiliary field and the main lens cause the electron beam to leave the main lens substantially parallel to the in-line plane, whereby the diameter of the electron beam at a gap of the main lens at the anode side is smaller than or equal to the diameter of the aperture of the second electrode throughout the deflecton of the electron beam across the display screen. By virtue thereof, an improved picture reproduction can be obtained.

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.