Abstract: Apparatus in a three-beam inline electron gun system for a color cathode ray tube, wherein the tube has a screen and a partially self-converging yoke which partially, but incompletely, converges the three beams and undesirably imparts astigmatism to the beams in off-center regions of the screen, applies a field-strength-dependent asymmetrical field to the two outer beams to provide partial dynamic convergence. The apparatus includes an electron beam source for developing three electron beams, a focusing lens portion for focusing the three electron beams at the tube screen, an astigmatism correcting lens portion for developing an astigmatic field component in the path of each of the beams, and a modulated voltage source for modulating the strength of the astigmatic field component as a function of beam deflection angle to at least partially compensate for the yoke-induced astigmatism and for modulating focus field strength in providing partial dynamic electron beam convergence.

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: For use in a color cathode ray tube (CRT) having a self-converging yoke for applying an asymmetric magnetic field in a synchronous manner to a plurality of inline electron beams for deflecting the electron beams across a phosphorescing screen in the CRT, wherein the magnetic field causes defocusing of and an astigmatism of the electron beams where incident upon the CRT screen in off-center regions of the screen, an electron gun comprising: a cathode for generating electrons; a beam crossover arrangement for receiving electrons from the cathode and for forming a beam crossover; a first electrostatic quadrupole field aligned in a spaced manner along the electron beams and having a first asymmetric aperture through which the inline electron beams pass for applying a first electrostatic quadrupole field to the electron beams in compensating for the defocusing and astigmatism of the electron beams; and a second electrostatic quadrupole field aligned in a spaced manner along the electron beams with the first electr

Abstract: For use particularly in a color cathode ray tube electron gun, means for diverting an electron beam from a straight line path. The beam diverting means has general utility, but is disclosed as part of a quadrupole lens for correcting astigmatism introduced by an associated self-converging yoke. The beam bending feature in the dynamic quadrupole compensates for convergence errors undesirably introduced by the dynamic focus voltage.

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: 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: The asymmetric beam focusing slot provides a two-part crossover of the electron beams. The slot has a length greater than the spacing between the outer apertures and a width greater than the diameter of the apertures. The screen grid also has an improved refraction lens which comprises a transversely disposed recessed portion including a substantially rectangularly-shaped central portion and substantially triangularly-shaped end parts. The refraction lens provides a compensating field between the screen grid and the main electron lens to offset any changes in the main electron lens caused by variations in the focus voltage in the main electron lens. The recessed portion has a length, extending in the plane of the electron beams, at least coextensive with the length of the slot, and a width, extending substantially orthogonal to the plane of the electron beams, substantially greater than the width of the slot.

Abstract: An improved color picture tube has an inline electron gun for generating and directing three electron beams, a center beam and two side beams, along coplanar paths toward a screen of the tube. The gun includes a main focus lens for focusing the electron beams. The main focus lens is formed by two spaced electrode members, each having three separate inline apertures therein, a center aperture and two side apertures. The improvement comprises each of the apertures in each of the focus lens electrodes having a shape that distorts a portion of the focus lens thereat, to at least partially compensate for an astigmatic effect within the tube that acts on an associated electron beam. The side apertures in both of the electrodes are nonsymmetrical about axes that pass through the respective side apertures and are perpendicular to the initial coplanar paths of the electron beams.

Abstract: A color picture tube includes a screen and an improved inline gun for generating and directing three inline electron beams along separate paths toward the screen. The improved electron gun has an asymmetric beam-forming region and an asymmetric main focus lens. The asymmetry of the main focus lens is matched with the asymmetry of the beam-forming region to focus substantially all portions of each of the beams at the screen.

Abstract: The present invention provides an improvement in a color picture tube having an inline electron gun for generating and directing three inline electron beams, comprising a center beam and two outer beams, along initially coplanar paths toward a screen of the tube. The beams pass through a deflection zone adapted to have two orthogonal magnetic deflection fields established therein. A first of the fields causes deflection of the beams perpendicular to the inline direction of the beams, and a second of the fields causes deflection parallel to the inline direction of the beams. The improvement comprises the electron gun including four magnetically permeable members located near the exit of the electron gun in a fringe portion of said deflection zone. A first and a second of the members are located between the center beam path and a first and second outer beam path, respectively.

Abstract: An inline electron gun for a cathode-ray tube includes a plurality of cathodes, a control grid, a screen grid and a main focus lens arranged successively in alignment with the cathodes for focusing a plurality of electron beams onto a screen. The screen grid has a given thickness with a plurality of transverse slots formed therein. The slots have a depth less than the thickness of the screen grid. An aperture is formed in each of the slots. The outer slots are asymmetric with respect to the apertures therein and are displaced transversely toward the center aperture. The transverse slots in the screen grid compensate for the vertical flare distortion of the beam spot at off-center positions on the screen and the asymmetric location of the outer slots reduces the horizontal convergence sensitivity of the outer beams with respect to focus voltage change.

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 and slots at each aperture on a side facing away from the control grid, a first focusing electrode having three inline apertures facing the screen grid and three inline apertures facing away from the screen grid, and a second focusing electrode having three inline apertures facing the first focusing electrode. The diameters of the control grid apertures are in the range of 0.43 mm to 0.59 mm. The screen grid is spaced 0.13 mm to 0.26 mm from the control grid. The diameters of the screen grid apertures are in the range of 0.43 mm to 0.59 mm, and their thickness is in the range of 0.20 mm to 0.31 mm. The ratio of the depth of the slots in the screen grid to their widths is in the range of 0.13 to 0.23. The diameters of the apertures in the facing portions of both focusing electrodes are in the range of 4.06 mm to 5.

Abstract: An inline electron gun in a color picture tube is improved by the addition of two slots that are spaced sufficiently close to and inward from the two apertures in a portion of the screen grid electrode facing an accelerating and focusing electrode. The slots cause a distortion of the electrostatic field formed between the two electrodes at the two apertures. The field distortion compensates for an opposite distortion within the main lens of the electron gun.

Abstract: In an electron gun that includes a cathode, a control grid, a screen grid and at least two main focus lens electrodes, an improvement comprises the screen grid including a first portion having a circular aperture, a second portion having at least one elongated aperture and a third portion having a circular aperture. The first and third portions are electrically insulated from the second portion.

Abstract: An improved color picture tube has an inline electron gun for generating and directing three electron beams, a center beam and two side beams, along coplanar paths toward a screen of the tube. The gun includes a main focus lens for focusing the electron beams. The main focus lens is formed by two spaced electrode members each having three separate inline apertures therein. Each electrode also includes a peripheral rim. The peripheral rims of the two electrodes face each other. The apertured portion of each electrode is within a recess set back from the rim. The width of the recess in at least one of the electrodes is wider at the center beam path than at the side beam paths, measured perpendicular to the plane containing the electron beam paths.

Abstract: An improved color picture tube has an inline electron gun for generating and directing three electron beams, a center beam and two side beams, along coplanar paths toward a screen of the tube. The gun includes a main focus lens for focusing the electron beams. The main focus lens is formed by two spaced electrode members each having three separate inline apertures therein. Each electrode also includes a peripheral rim. The peripheral rims of the two electrodes face each other. The apertured portion of each electrode is within a recess set back from the rim. The main focus lens electrode closest to the screen includes a slot on the side facing the screen. The slot extends in the direction of the three electron beam paths and includes means for providing a weaker stigmator effect on the two side beams than on the center beam.

Abstract: An electron gun comprises an astigmatic beam forming means including a cathode, a control grid, a first screen grid electrode having a horizontally elongated rectangular aperture, and a second screen grid electrode having a circular aperture. In operation, the second screen grid is energized with a DC bias voltage and the control grid and first screen grid is energized with a DC bias superposed with a substantially parabolically shaped dynamic signal synchronized with either or both the horizontal and vertical deflection signals. Thus, the astigmatic optics of the beam forming means varies in strength in phase with the beam scan so as to provide optimum correction for flare distortion of the electron beam.

Abstract: The electron gun, which is especially adapted for use in color picture tubes, comprises in the order named: a cathode, an apertured-plate control grid (G1), an apertured-plate screen grid (G2), and at least two tubular focusing electrodes. The quality of the gun's beam spot is improved by: 1. Establishing an operating electric field between the G2 and G3 which is between about 100 and 400 volts/mil, thereby reducing aberration effects in the beam-forming region of the gun; 2. Making the G2 thick so as to prevent the high G3 voltage from penetrating the region between the G1 and G2, thereby allowing the G1-G2 field to provide a divergent effect on the electron beam prior to beam crossover and thus give a reduced crossover angle; 3. Spacing the main focusing lens at a distance from the G2 so as to provide an optimum filling of the main focus lens with the beam to maximize the object distance of the focusing system; and 4.

Abstract: The gun, for use in a television picture tube, comprises a cathode, an apertured control grid, and an apertured screen grid aligned in the order named. The screen grid aperture comprises a rectangular slot portion facing the control grid and a circular portion facing away from the control grid. The slot portion of the aperture, which has a width 2-5 times its depth, creates an astigmatic field that produces underconvergence of the electron beam in the vertical plane only, whereby to avoid and/or compensate for vertical flare distortion of the beam spot at off-center positions on the image screen.