| 摘要 |
PURPOSE:To obtain a picture of high quality, in which slippage of especially longitudinal lines of the central beam and the side beam in the diagonal direction are removed, by providing a pair of the magnetic field control elements having the central electron beam emitting hole positioned therebetween, and projected in the tube-axial direction at least on the horizontal axis with respect to the central beam emitting hole. CONSTITUTION:The magnetic field control elements 14 and 15 are provided in the neiborhood of the electron beam emitting holes 5, 6 and 7 of an electron gun electrode. The magnetic field control elements 14 and 15 have the projection parts in the direction of the tube axis including the horizontal axis and having the central beam emitting hole 6 positioned therebetween. And said projected parts are in the shape, in which the height h1 of the portion of the width y1 in the part including the horizontal axis is lower than the projection height h2 of the part not including the horizontal axis. By said magnetic field elements 14 and 15, the central beam and the side beams near the diagonal lines can be focused while removing slippage of the longitudinal lines.
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