| 摘要 |
PURPOSE:To correct the deformation of a beam spot, by fitting the large- diameter portion of a core with an additional coil for generating a magnetic field having a component which has an intensity near that of the tube-axial component of a magnetic field generated by a vertical deflection coil and is reverse in direction to the tube-axial component. CONSTITUTION:A deflector, which is attached to the outside of the funnel-shaped portion of a picture tube, comprises a funnel-shaped core 3-2, a toroidally-wound vertical deflection coil 3-1, and a horizontal deflection coil 3-5 wound in the form of a saddle. An additional coil 3-6 is provided so that a portion thereof is fitted inside the large-diameter portion 3-4 of the core 3-2 and another portion of the coil 3-6 is fitted outside the small-diameter portion 3-3 of the core. The additional coil 3-6 generates a magnetic field having a component which has an intensity near that of the tube-axial component of a magnetic field generated by the vertical deflection coil 3-1 and is reverse in direction to the tube-axial component. The magnetic field generated by the additional coil 3-6 acts to the bow-shaped magnetic field generated by the vertical deflection coil 3-1 at the large-diameter portion 3-4 of the core 3-2. As a result, a nearly circular beam spot is provided.
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