To provide a display tube capable of correcting a deflection error of the vertical direction of a center beam without exerting an influence on a deflection error of the horizontal direction.
This display tube has such a formation that an upside ferromagnetic extension core part 15 and downside ferromagnetic extension core part 16, formed on a core end surface 14, facing to the electron gun system 4 side, of a ferromagnetic ring core 9, projectingly and parallel to an axis line 6 toward the electron gun system 4 side from the upper part and the lower part, are installed. As a region affected by a transverse magnetic field is expanded toward the electron gun system 4 side, the transverse magnetic field having a longer distance relative to a center beam can be added, and the most suitable transverse magnetic field, which has the maximum intensity on the passing route of the center beam and attenuates toward the horizontal right and left directions where the passing route of another electron beam 3 is positioned, can be formed. Therefore, the display tube, capable of correcting a deflection error of the vertical direction of the center beam without exerting an influence on a deflection error of the horizontal direction, can be provided.
IIJIMA AKIRA
KAN KIKO
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