Abstract: A system for generating magnetic fields to converge a plurality of electron beams in a cathode-ray tube including at least one convergence yoke having a core with a ring-shaped outer periphery and a plurality of magnetic poles on an inner periphery thereof extending toward a neck part of the cathode-ray tube for forming magnetic paths therewith.

Abstract: A convergence system for a cathode-ray tube having three detection magnetic pole pieces are disposed opposing to each other on both sides of a center beam for forming magnetic paths inside the neck part of a cathode-ray tube. A first convergence yoke is disposed outside the neck part of the cathode-ray tube for forming magnetic paths together with the magnetic pole pieces. A first coil is wound on a first convergence yoke to generate a magnetic field for correcting horizontal misconvergence between the center beam and a side beam on a side of the center beam. A second coil is wound on the first convergence yoke to generate a magnetic field for correcting horizontal misconvergence between the center beam and a side beam on the other side of the center beam. A third coil is wound on the first convergence yoke to generate a magnetic field for correcting vertical misconvergence between the center beam and both side beams.

Abstract: A ring magnetic sub-core having a plurality of protrusions inside is disposed adjacent to an electron gun side of a main magnetic core on which a horizontal deflection coil and a vertical deflection coil are wound, and an auxiliary vertical deflection coil connected with said vertical deflection coil is wound around said magnetic sub-core, thereby making it possible to have both improvement of convergence performance and reduction of barrel distortion be consistent with each other. Further, a convergence coil is wound around said magnetic sub-core so as to correct a transverse raster or a longitudinal raster.

Abstract: A focus adjusting device for projection display, comprising at least one set of 4-pole magnetic field generating means, and adjustment means for adjusting the magnetic field strength of the 4-pole magnetic field generating means so as to eliminate astigmatism caused by fabrication error and attachment error of an electron gun and a focus coil.

Abstract: The present invention relates to a deflection yoke device which is preferably combined with an in-line type color picture tube having electron guns aligned horizontally. The distribution of magnetic fields is determined in the horizontal direction such that a sharp or strong barrel magnetic field is localized on the side of the neck portion whereas an extremely sharp pincushion magnetic field is localized on the side of the funnel portion and at the same time, an intensely sharp pincushion magnetic field is distributed between the funnel portion and the neck portion. The central electron beam is deflected more at a greater angle than side electron beams so as to land outside the side electron beams.