Magnetic device for correcting image geometry defects for cathode-ray tubes

Abstract

Deflection yoke for cathode-ray tubes with a north/south geometry correction comprising a pair of horizontal deflection coils and a pair of vertical deflection coils, the two pairs being isolated one from the other by a separator, a ferrite ring at least partly covering the deflection coils and having a flared front part, the deflection yoke comprising in its front region at least one pair of magnetic means to modify locally the magnetic field in the said front region and to correct the geometry of the image created on the screen of the tube, the magnetic means being placed in the space in such a way that, for a plane containing the longitudinal axis of the deflection yoke and the axis of symmetry of a magnetic means, and for the point M of the plain corresponding to the point of minimum coordinates of the said means, the intersection of the ring with is at least partly in its front part, located outside the region delimited by the half line passing through M and perpendicular to Z, and the half line passing through M and making an angle of 45° with.