| 摘要 |
PURPOSE:To prevent a drop in color purity due to an external stray magnetic field by providing an external magnetic shield with a diagonal side extension part nearing and covering the diagonal part of a vacuum enclosure. CONSTITUTION:The diagonal part of an external magnetic shield 7 is provided with a diagonal side extension part 7c for connecting a long-side extension part 7a to a short side extension part 7b along the diagonal part of a panel part. And this diagonal side extension part 7c is provided with a notch 7d for passing a fitting member. When a magnetic field is applied in four orthogonal directions, the diagonal side extension part 7c of the external magnetic shield 7 becomes a passage for a line of magnetic force, because of the position thereof near the diagonal part of a color cathode-ray tube. And a magnetic flux flows toward the long side extension part 7a. Also, the notch 7d for passing the fitting member is formed at the diagonal side extension part 7c and, therefore, a leak magnetic flux is generated at the notch 7d. As the extension part 7c is so shaped as to be appropriate for a magnetic field passage, however, the aforesaid leak magnetic flux can be made extremely small, compared with a leak magnetic flux at the diagonal part of the external magnetic shield 7. |
