Abstract: A CRT electric field shield display apparatus with an FBT having a plurality of high voltage output terminals, includes an offset voltage generator generating an offset voltage to offset an electric field due to high voltages outputted from the plurality of high voltage output terminals; and an electric field shielding member disposed around the FBT and having a conductor to which the offset voltage is applied.

Abstract: A deflection yoke mounted on a rear portion of a cathode ray tube (CRT) to deflect an electron beam emitted from an electron gun of the CRT includes a coil separator mounted on the CRT, a horizontal deflection coil mounted on an inside of the coil separator, having a first section generating a horizontal deflection magnetic field deflecting the electron in a horizontal direction and having a first radius, having a second section generating a magnetic field to weaken the horizontal deflection magnetic field and having a second radius different from the first radius, a vertical deflection coil mounted on an outside of the coil separator and generating a vertical deflection magnetic field deflecting the electron beam in a vertical direction, and a ferrite core covering a portion of the vertical deflection coil to strengthen the horizontal deflection magnetic field and the vertical deflection magnetic field.

Abstract: In a convergence correction device according to the present invention and a cathode-ray tube using such convergence correction device, a core having wound thereat a vertical correction coil (M/Dv) to which a vertical deflection current is applied is used while such core is being saturated. Also, such core might be made of a material having a characteristic in which a changed amount of a reactance per deflection velocity becomes less than a predetermined value. The above-mentioned predetermined value is less than 2000 &mgr;H/msec, for example. Thus, a convergence pattern, which is difficult to correct at the intermediate portions of upper and lower separated screens of a cathode-ray tube according to the related art, may be satisfactorily corrected without producing bright and dark stripes on the screen of the cathode-ray tube.

Abstract: Deflection yoke for a cathode ray tube including horizontal and vertical deflection coils for deflection of electron beams emitted from an electron gun in horizontal and vertical directions, respectively, a ferrite core disposed to surround the vertical deflection coil for improving a magnetic efficiency, an holder adapted to fix positions of the horizontal and vertical deflection coils and the ferrite core and insulate the horizontal and vertical deflection coils, and a magnet provided on an upper side and a lower side of a flange part formed at a screen side of the holder for canceling a magnetic field leaked from the horizontal deflection coil at the screen side of the holder.

Abstract: This invention relates to an apparatus for compensating convergence in a color cathode ray tube, more particularly to an apparatus for minimizing the convergence drift variance of R and B electron beams on a screen so as to improve convergence characteristics and a picture quality on the screen. The apparatus for compensating convergence drift comprising: a convergence purity magnet for converging the electron beams emitted from the electron gun on the specific point of the screen of the color cathode ray tube; and a supplementary magnet ring 52 with at least four-magnetic pole contacting the neck N between a second grid electrode 24 and the deflection yoke 60. Particularly, the supplementary magnet ring is mounted on a holder 48 of the convergence purity magnet 40 and has a pole arrangement to move the convergence of the R and B beams in the direction opposite to the electron gun from the screen.

Abstract: A pair of magnetic bodies extending in an axial direction of a color cathode ray tube are arranged apart from each other in a direction perpendicular to the axial direction so as to shield an external magnetic field acting on three electron beams forming a row in the direction perpendicular to the axial direction. A ring-like 6-pole magnet plate disposed in a plane perpendicular to the axial direction is arranged in substantially a central region in a longitudinal direction of the magnetic bodies. These 6-pole magnet plate and magnetic bodies arranged in the particular positional relationship generate a magnetic field distributed to have a plurality of peaks of intensity on the orbit of the central beam. The magnetic field runs on the orbit of the central beam toward one magnetic body around one of the peaks, and runs toward the other magnetic body around the adjacent peak.

Abstract: A cathode ray tube apparatus that can reduce the leakage extraneous electric field with low cost. The cathode ray tube apparatus comprises a front panel, a glass bulb having a funnel part including an anode terminal at the outer surface thereof and a neck part including an electron gun, a deflection apparatus comprising a horizontal deflection coil on the outer surface of the funnel part and the neck part of the glass bulb, a flyback transformer connected to the anode terminal of the funnel part via a first lead wire having an insulating coating, and a leakage extraneous electric field controller installed on the first lead wire. The controller reduces the leakage of the extraneous electric field from the first lead wire.

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 color cathode ray tube includes a three beam inline electron gun; a deflection device for performing deflection and self-convergence; a static beam convergence device having permanent magnets for generating a magnetic field adjustable to converge three electron beams at a central portion of a phosphor screen; and a dynamic convergence device having coreless electromagnetic coils for generating a magnetic field adjustable to converge three electron beams at peripheral portions of the phosphor screen. The dynamic beam convergence device includes a spiral coil conductor formed on a non-magnetic film.

Abstract: In an in-line beam type CRT, at least one pair of quadrupole electromagnets and at least one pair of quadrupole electromagnets rotated by 45.degree. about a beam axis are provided around a neck portion of a deflection yoke. Further, electric field lenses for respectively applying quadrupole electric fields to beams are mounted to an electron gun. Thus, the CRT can provide satisfactory spot shapes over the entire surface of a screen thereof and hence achieve high resolution.

Abstract: A deflection yoke includes a first core portion and a core extension portion. The core extension portion is located in the rear of the yoke closer to the beam entrance region. To adjust the yoke for the particular cathode ray tube on which it is mounted, the position of the yoke is adjusted for obtaining acceptable image geometry. Then, the core extension is moved with respect to the first core portion in a direction perpendicular to the longitudinal axis of the tube to obtain convergence symmetry while the position of the first core portion remains the same. In this way, convergence symmetry adjustment is accomplished separately from image geometry adjustment.

Abstract: A stray magnetic field suppression system for use in a CRT image display suppresses a stray magnetic field that emanates from the horizontal deflection coil of a beam-deflecting yoke which is energized by sawtooth waveform pulses from a horizontal oscillator. The system comprises two series-connected magnetic coil assemblies in conjunction with a capacitor and activated by the sawtooth waveform pulses. The capacitor serves to integrate the pulses, enabling the suppression system to form an effective field for suppressing a stray magnetic field when the magnetic coil assemblies are interposed in the path of the stray magnetic field on opposite sides of the yoke.

Abstract: A pair of saddle type horizontal deflection coils are provided at those upper and lower places on the inner wall of the coil separator. Vertical deflection coils toroidally wound on a core are provided on the outer periphery of the coil separator. Neck-side magnetic pieces are provided at those upper and lower sides of the neck-side area between the coil separator on one hand and the vertical deflection coils on the other hand. A pair of magnetic pieces, right and left, are provided, as a pair of crossarms, on the coil separator at a front-side section. In a deflection yoke apparatus thus provided, magnetic field creation areas at the crossarms are provided mainly on a Y axis side and four permanent magnets are provided on the front-side flange section of the coil separator at an angle of about 10.degree. relative to an X axis so that these permanent magnets are magnetized substantially in a tube direction of a CRT.

Abstract: A monochrome cathode ray tube including a magnetic focusing device provided with means for generating a static magnetic focusing field. These means surround the neck of the cathode ray tube without contacting this neck, and a system of correction coils for generating an additional focusing field and 2-, 4- and/or 6-pole fields is provided coaxially between these means and the neck of the tube.

Abstract: A shadow-mask color picture tube has an auxiliary deflecting device located between the deflection yoke and shadow mask. In a picture tube with in-line electron guns, the auxiliary deflection device includes a pair of deflection coils, for example, for deflecting the electron beams in the horizontal direction. In a picture tube with delta electron guns, the auxiliary deflection device includes two pairs of deflection coils, for example, for deflecting the electron beams in both the horizontal and vertical directions. The auxiliary deflection devices deflect the electron beams by an amount that closely aligns them with the doming direction of the shadow mask, thereby reducing landing error and improving color purity.

Abstract: A color cathode-ray tube-yoke combination comprises a color cathode-ray tube having a glass envelope and a yoke for producing magnetic fields positioned thereon. At least one semi-flexible corrective magnet is attached to a curved portion of the envelope. The novel corrective magnet is improved over prior corrective magnets by the inclusion therein of at least one portion of reduced thickness which increases the flexibility of the corrective magnet to provide conformity to the curved surface portion of the envelope.

Abstract: A system for improving the operation of a cathode ray tube (CRT) is disclosed whereby interference caused by external magnetic fields is mitigated. The system comprises a CRT having a CRT magnetic shield housing and at least one electromagnetic field sensor disposed adjacent to the inner surface of the CRT housing. Sensors form to generate a reference magnetic field and to generate a sensor output signal in response to the detection of both the reference field and an external field as sensed within the housing. A bucking field coil drive circuit is provided in electrical communication with the field sensor, the drive circuit being operative to generate a bucking field coil drive signal responsive to the field sensor output signal. A bucking field coil is disposed circumferentially about the CRT and is driven by the bucking field coil drive signal.

Abstract: As CRT display is housed in a magnetic shield to reduce the image distortions caused by the external magnetic field produced by an NMR scanner. To further improve image quality, three sets of compensating coils are positioned around the CRT display and inside the shield to produce magnetic fields which offset the effects of the residual external magnetic field components that penetrate the shield or enter through the window in the shield used to view the CRT screen.

Abstract: Disclosed are a method of measuring the color purity of a color display having phosphors in the shape of dots and an apparatus therefor which are capable of quantitatively measuring the state of the phosphors being irradiated with electron beams with high accuracy. Magnetic field is applied to the color display tube from the outside so as to forcibly move an electron beam deflectively along a straight line and a photograph of the phosphor in this state is taken so as to obtain the configuration (the center position, and the radius or the diameter) of the phosphor from the image of the phosphor. After the two center positions of the electron beams in the positive and negative directions of the external magnetic field are then obtained, the center position of the electron beam under no excitation is obtained as the interior division point.

Abstract: An electron gun producing a spiral electron beam for gyrotron devices comprises means for producing an axial magnetic field propagating the beam axially beyond the anode of the electron gun, and separate electromagnets for producing a transverse "kicker" electromagnetic field beyond the anode and perpendicular to the magnetic propagation field such as to apply a transverse impulse of short duration, imparting a transverse motion, to the electrons to cause them to spiral as they are propagated axially beyond the anode.

Abstract: To correct the effects of an in-line electron gun mount rotation error on a kinescope display screen, initially the horizontal deflection axis of the yoke is aligned with the actual axis of alignment of the electron guns. The resultant rotated raster is then rotated into alignment with the kinescope major and minor axes through the use of a magnetic field disposed orthogonal to the yoke deflection fields. The magnitude of the field is selected to effect the desired magnitude of raster rotation, while the polarity of the field is selected to effect the desired direction of raster rotation. In one embodiment, a coil of wire placed to abut the kinescope funnel in front of the deflection yoke and powered by a variable DC voltage source provides the desired magnetic field. In another embodiment, a permanent magnet ring takes the place of the coil -DC source combination.

Abstract: An improved fine deflection, for use in an electron beam optical system, utilizes a magnetic deflector positioned adjacent to the surface of the target most remote from a matrix lens, which is positioned between the target and an electron beam emitter. The matrix lens is a single plate having multiple apertures forming matrix lenslets and has an electron beam accelerator positioned between the lens and the target for uniform acceleration of the electron beam passing through a selected one of the lenslets.