| 摘要 |
PURPOSE:To get rid of the axial separation of an electron beam at a main lens as well as to make a halo in and around a faceplate reducible, by connecting a coil of a compensator to a vertical deflecting coil electrically in series or parallel. CONSTITUTION:When an electron beam 5 is deflected to the upside of a faceplate by a deflecting yoke, electric current flows into a coil 22 in such a direction as shown by an arrow in illustration. With this current flow, it comes to generate a corrective magnetic field 24 in the right direction in consequence, so that a vertical deflecting leakage field 25 can be offset. And, axial separation of the electron beam 5 at a main lens area attributable to this field 25 is reducible to the minimum. Therefore, since the electron beam 5 is able to minimize distortion of the beam received from spherical aberration of the main lens, a halo to be produced inward at an upper part of the faceplate is thus reducible.
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