Asymmetric shunt for deflection yoke for reducing diagonal symmetric defects

A deflection yokes for a cathode-ray tube, comprising:

• a pair of horizontal deflection coils and a pair of vertical deflection coils for generating magnetic deflection fields perpendicular to a main axis of said cathode-ray tube, one of said pairs consisting of saddle-shaped coils having conductive wires arranged so as to form a front conductor assembly and a rear conductor assembly coupled to each other by lateral conductor bundles, and those parts of each of said coils which form the rear conductor assembly and the lateral bundles being arranged approximately symmetrically with respect to a plane;
• a first metal plate placed near the front conductor assembly for locally modifying one of the direction and the amplitude of the magnetic field created by the current flow in said front conductor assembly so that, considering a first zone of the front conductor assembly and a second zone symmetrical with the first zone with respect to the plane, the fields created in the first and second zones are not symmetrical with respect to said plane;
• and
• a second metal plate wherein said first and second metal plates extend on both of the saddle-shaped coils of the same pair, symmetrically with respect to the Z axis, the first and second metal plates locally modifying the amplitude of the magnetic field with the same strength.