Cathode ray tube having an improved core

A cathode ray tube, comprising:

• a glass front panel;
• a funnel fastened to the panel, the funnel including a neck part and a screen part opposing the neck part, wherein the screen part is fastened to the panel;
• a fluorescent screen formed on an interior surface of the panel;
• a shadow mask disposed a predetermined distance from the fluorescent screen;
• an electron gun coupled to the neck part for emitting electron beams, the electron beams formed of a plurality of electrons;
• a deflection yoke for deflecting electrons within the electron beams in horizontal and vertical directions, wherein the deflection yoke includes a horizontal deflection coil for horizontally deflecting electrons within the electron beams and a vertical deflection coil for vertically deflecting electrons within the electron beams;
• a core for reducing loss in the strength of a magnetic field generated by the horizontal and vertical deflection coils, the core including an attaching portion;
• and
• a holder for holding and insulating the horizontal and vertical deflection coils, wherein
• along a cross section perpendicular to an axis of the funnel, a thickness of the attaching portion of the core is different from a thickness of a portion of the core proximate a portion of the funnel fastened to the panel.