PURPOSE: To improve the deflection characteristic, convergence characteristic and the focus characteristic by providing a plurality of magnetic yokes in an electromagnetic focusing cathode ray tube.
CONSTITUTION: There electrode sections or a cathode 2, first grid 3 and second grid 4 are arranged in a casing 1 while third grid bottom 5 and three pairs of magmetic yokes 6a, 6b, 6c, 6d and 6e, 6f are arranged while facing each other on same tube axis. Then a focusing permanent magnet 9 is arranged at the outside of said yokes 6c, 6d. Consequently the leakage field of the permanent magnet 9 is localized in the gaps 6g, 6e and 6f of each magnetic yoke to form the focusing field lenses 15a, 15b and 15c thus to improve the focus characteristic. While since the leakage field isn't produced at all at the cathode side and the phosphor face side of said yokes 6a, 6f the deterioration of the deflection characteristic and the convergence characteristic can be suppressed.
OSAKABE KUNIHARU
FUKUDA KIYOUHEI
