Abstract: A method for operating a cathode-ray tube electron gun, suitable for multimode operation, for example, in order to display television images and multimedia images of the SVGA, XGA type, in which the zone for forming the electron beam generated by the cathode has at least two control electrodes. The two control electrodes are connected to voltage sources in such a way that the potential difference between the two control electrodes increases when the beam current decreases.

Abstract: The invention relates to a cathode structure intended to be inserted into an electron gun for a cathode-ray tube. The cathode comprises a cathode body on the end of which is placed an emissive pellet, the cathode body being held in place inside a sheath by supporting means which comprise: a first series of branches, each branch being connected on one side to the cathode body and on the other side to an intermediate piece 30; and a second series of branches, each branch being connected on one side to the sheath and on the other side to the same intermediate piece.

Abstract: The coils of an astigmatism corrector for an electron beam of a cathode ray tube are positioned on a flexible support. The support is disposed around the neck of the tube and positioned at least partially adjacent the back part of at least one pair of deflection coils, so as to reduce interaction of the fields produced by the astigmatism corrector with the elements of the electron gun.

Abstract: A video display deflection apparatus includes a vertical deflection coil. A separator is used for mounting the vertical deflection coil thereon. The separator has a funnel shaped first part conforming to a shape of a neck of the cathode ray tube and a second part forming a front portion of the separator close to the screen. A degree of flare of the first and second parts is substantially different. A saddle shaped, horizontal deflection coil is mounted on the separator for producing a deflection field to scan the electron bean along a horizontal axis of the display screen. The horizontal deflection coil includes a plurality of winding turns forming a pair of side portions, a rear end turn portion, close to an electron gun of the tube and a front end turn portion, close to the screen. At least a portion of the front end turn portion, in a radial angular position ranging between 0 and 30 degrees, is supported on the second part of said separator away from the boundary.

Abstract: An deflection yoke for a color cathode ray tube includes a saddle shaped vertical deflection coil and a saddle shaped horizontal deflection coil. The horizontal deflection coil includes winding turns forming a pair of side portions having a winding window therebetween extending free of conductor wires. Each of the side portions has first and second winding spaces. The first winding space forms an aperture occupying an angular range between 30 and 45 degrees and having a length dimension greater than one half a length dimention of the window. A corner portion of the second winding space is disposed in a Z-axis coordinate selected in a range between a Z-axis coordinate of an end of the window, close to the electron gun of the tube, and a Z-axis coordinate, closer to the screen of the tube. The length of the range is approximately 10% of a length of the window.

Abstract: A deflection yoke for a color cathode ray tube includes a saddle shaped vertical deflection coil and a saddle shaped horizontal deflection coil. The horizontal deflection coil includes winding turns forming a pair of side portions, a front end portion, close to a screen of the tube, and a rear end portion, close to an electron gun of the tube. The side portions form a winding window free of conductor wires therebetween extending between the front end turn portion and the rear end turn portion. Each of the side portions has first, second and third winding spaces. The first, second and third spaces extend into longitudinal coordinates that are closer to an electron gun of the tube than an end portion of the window established by the end turn portion.

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 deflection yoke for a color cathode ray tube includes a saddle shaped vertical deflection coil and a saddle shaped horizontal deflection coil. The horizontal deflection coil includes winding turns forming a pair of side portions having a winding window therebetween extending free of conductor wires. The side portion has a winding space for correcting corresponding portions of coma and convergence errors. A corner portion of the winding space is disposed in a Z-axis coordinate selected in a range between a Z-axis coordinate, defining the end of the window that is close to the electron gun of the tube, and a third Z-axis coordinate, closer to the screen of the tube. The length of the range may be approximately 10% of a length of the window. Correction of convergence error, horizontal coma error or coma parabola error may be obtained without using field shapers such as shunts or magnets.

Abstract: The present invention provides an improvement in a method of making a plurality of color picture tubes of approximately the same size and including a mix of at least two different types of electron guns therein. The electron guns include each a plurality of electrodes, with each electrode having openings for the passage of three electron beams. The improvement comprises selecting materials for each electrode of the at least two different types of electron guns that will produce a minimum difference in the focus voltage sensitivities between the two different types of electron guns.

Abstract: An electron beam deflection device for cathode ray tubes comprises a pair of vertical deflection coils, a pair of horizontal deflection coils. At least one of the vertical deflection coils and the horizontal deflection coils has a saddle shape. A rigid separator supports the deflection coil pairs and insulating one from the other. An attachment element is coupled to the separator for securing the separator to a neck portion of the tube. The attachment element has a position on the neck and extends into a region under the vertical deflection coil pair.

Abstract: A deflection yoke for a cathode ray tube having a large, flat faceplate and a 4:3 aspect ratio includes a saddle-shaped vertical deflection coil. Most of the winding turns at a rear end portion are concentrated close to the beam entrance end of the coil. Both the position of the peak and the vertical deflection center of the vertical deflection field are shifted toward the gun entrance end with respect to the corresponding peak and deflection center of the horizontal deflection field. Consequently, North-South magnets are not required for reducing North-South pincushion distortion. Also, a much shortened yoke is obtained than if the peak were not shifted.

Abstract: An improved inline electron gun of the invention includes a plurality of electrodes spaced from three cathodes. 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. The main focus lens is formed by the facing portions of two electrodes. The improvement comprises the facing portions of the main focus electrodes including a first part, and a second part positioned within the first part. The first part includes a single aperture therein. The second part includes three inline apertures therein. The first part includes four spaced ledges, and the second part is attached to the four ledges.

Abstract: A deflection device for a cathode-ray tube with three coplanar guns, comprising a pair of horizontal deflection coils and a pair of vertical deflection coils, each horizontal deflection coil having a main deflection winding extending over the length of the deflection device, and an auxiliary deflection winding. Each main deflection winding has a front portion and a rear portion. The auxiliary deflection winding is disposed in the front portion of the main deflection winding and is arranged to generate a magnetic field opposed to a field of the main deflection winding.

Abstract: A deflection yoke for a cathode-ray tube, includes a pair of vertical deflection coils, a pair of horizontal deflection coils and a rigid separator insulating the pairs of deflection coils from each other. The separator has on its surface an arrangement for positioning and holding in place front and rear parts of saddle-shaped deflection coils. The arrangement forms an integral part of a body of the separator and is produced when molding the body.

Abstract: An improved cathode structure for a cathode ray tube includes a first metal tube which can receive an emission part and a heating element, a second metal tube constituting the cathode shielding, and means for retaining the first tube in position inside the second, wherein the retaining means are constituted by a single metal piece. In a preferential mode of implementation, the metal retention piece is constituted by a crown having branches extending in the direction of the axis of the crown.

Abstract: A cathode ray tube display with scanning beam velocity modulation comprises a cathode ray tube with a neck and gun for generating an electron beam. A deflection yoke is mounted on the cathode ray tube for electron beam deflection. A first flexible support having a side for conductor fabrication and a second flexible support having a side for conductor fabrication are superimposed and wrapped to conform to the neck circumference. A first coil pattern is formed as a conductor on the first conductor fabrication side and a second coil pattern is formed as a conductor on the second conductor fabrication side. A conductive connection couples between the first coil pattern and the second coil pattern. A connector couples scanning velocity modulation current to energize said first coil pattern and said second coil pattern for scanning beam velocity modulation.

Abstract: A yoke separator or liner includes a body having a conical shape and a ring shaped retraining member that is attachable to a rear portion of the body by four pairs of pawls and studs. A beam s velocity modulation coil is installed on a support member made of flexible material using a printed circuit technique. The studs are inserted in orifices formed in the support member. The pawls snap onto the studs and press against the support member in a manner to secure the modulation coil.

Abstract: A deflection yoke for a cathode ray tube includes a pair of vertical deflection coils, a pair of horizontal deflection coils and a rigid separator or yoke liner isolating the pairs of deflection coils from each other. The separator has a constant thickness and has on its inside face supporting ridges of a variable height for supporting the horizontal deflection coils.

Abstract: A deflection yoke for a cathode ray tube includes a pair of saddle-shaped horizontal deflection coils, a pair of saddle-shaped vertical deflection coils separated from the horizontal deflection coils by a rigid separator. The separator is formed from a funnel-shaped main body and a removable rear ring. The rear ring has an arrangement for locking to the main body and partially covers the back of the vertical deflection coils. Arms are placed around an external periphery of the rear ring that extend towards a core made of magnetic material. The core is placed around the vertical coils. The arms hold the core in place.

Abstract: A focusing device for a cathode ray tube comprises a plurality of substantially cylindrical permanent magnets, each having a longitudinal axis. A holder positions the magnets in an annular array at substantially equally spaced intervals in which the axes are substantially parallel to one another. Annular flanges of high magnetic permeability are disposed over longitudinally opposite ends of the magnets. First and second annular windings are symmetrically disposed substantially adjacent to and inwardly from the array of magnets. The magnetic mass of the focusing device can be varied by changing the number of magnets and/or the length of the magnets in the array. The magnets are magnetized in situ in the array by energizing a winding common to each of the magnets, after which the common winding is removed.