COLOR DISPLAY TUBE WITH IMPROVED COLOR SELECTION ELECTRODE

摘要

In known color display tubes (1) the shadow mask (13) has an apertured central area (20), a skirt (22) and a circumferential blind edge (21) located between the apertured central area (2) and the skirt (22). In known shadow masks (13) the amount of material per unit area shows a discontinuity at the transition areas (23, 24) between the central area (20) and the blind edge (21) and between the blind edge (21) and the skirt (22). This leads to a different yield strength in these areas making drawing of the shadow mask (13) more difficult. In the invention the circumferential blind edge (21) has a gradual increasing amount of material per unit area when going from the central area (2) in the direction of the skirt (22). This enables a continuous behaviour of the yield strength over the transition areas (23, 24). The mask is easier to draw, deformations are less and the performance of the color display tube (1) improves with respect to color purity, microphony and droptest.