Deflection yoke for cathode ray tube

A cathode ray tube display device, comprising:

• a cathode ray tube;
• a deflection yoke body including horizontal deflection coil means for generating a horizontal deflection magnetic field, vertical deflection coil means for generating a vertical deflection magnetic field and a ferrite core;
• and
• an upper cancelling coil and a lower cancelling coil for cancelling an undesired magnetic field generated by said deflection yoke body,
• said upper and lower cancelling coils being arranged above and below said deflection yoke body, for generating a cancelling magnetic field for substantially cancelling undesired portions of the horizontal deflection magnetic field, said upper and lower cancelling coils being arranged between a front end of said horizontal deflection coil means and a center of said ferrite core and in parallel to an axis direction of said deflection yoke body, the undesired portions of the horizontal deflection magnetic field in a front region and a rear region of said deflection yoke body being under-corrected and over-corrected, respectively.