| 摘要 |
PURPOSE:To reduce displaced colors due to doming occurring on a shadow mask, by arranging the through holes in a shadow mask in a plurality of vertical columns running perpendicularly to the plane including the electron guns and by setting the pithes between the columns to be maximum or the largest at the center of the shadow mask and at the end portions thereof and to be minimum at the middle portion of them. CONSTITUTION:The through holes in a shadow mask 10 are arranged in plurality of columns running perpendicularly to the plane including the electron guns, and the pitches a between the columns are set to be maximum or the largest at the center O of the shadow mask and at the end portions thereof + or -XM in the direction perpendicular to the columns and to be minimum at the middle portions of them. The pitches are also set in such a way that the pitches are monotonously decreasing from the center O to the middle portions and monotonously increasing from the middle portions to the end portions + or -XM. If, for example, a graph is made taking the horizontal pitches a of the shadow mask 10 on the axis of ordinate and the positions on the shadow mask on the axis of abscissa, the pitches a are represented by a waveform as shown in the soid line h, in which there are formed two shapes with a small radius of curvature on both sides of the center, whereby formation of the doming on the both sides can be reduced. |
