Deflection yoke apparatus with means for reducing unwanted radiation

Claim 1

A deflection yoke apparatus, which is mounted on a neck of cathode-ray tube for projecting rasters on a screen by scanning at least one electron beam, said deflection yoke apparatus comprising: a pair of horizontal deflection coils generating a magnetic field to deflect said electron beam in a horizontal direction; a pair of vertical deflection coils generating a magnetic field to deflect said electron beam in a vertical direction; a coil separator electrically insulating between both said vertical and horizontal deflection coils, said coil separator being provided with a front expanded part at a front end and a rear expanded part at a rear end; an annular deflection core forming a magnetic path for a magnetic flux, generated when a deflection current is supplied to said horizontal and vertical deflection coils, a deflection magnetic field, for deflecting said electron beam inside said annular deflection core, and an externally leaking magnetic field outside said annular deflection core; an auxiliary coil means being arranged at least at one of two positions in said vertical direction outside said deflection core, said auxiliary core means for generating a magnetic field with a direction opposite to a direction of said externally leaking magnetic field when a horizontal deflection current is supplied to said auxiliary core means; and an engaging means for fixing said auxiliary coil means to said coil separator.