| 摘要 |
PURPOSE:To remarkably improve the resolution of a screen peripheral section with hardly deteriorating the resolution of the screen center by forming a sectional shape in the direction vertical to a face containing three in-line arrangement electron beams into an ellipse. CONSTITUTION:The shape of an auxiliary electrode provided at the inner part of an electrode forming a principal lens is formed into an ellipse at the cross section perpendicular to a face containing three in-line arrangement electron beams. In this case, supposing that the diameter of the three pricipal lens electrodes in the aperture arrangement direction is (b) and the diameter of the principal lens electrode in the direction vertical to the aperture arrangement direction is (a), a>b is obtained. If the ratio of (a) to (b) is ncreased here, the resolution at the screen center is deteriorated. As a result, the values (a) and (b) are determined so that the uniformity of focusing over the whole screen can be obtained. |
