| 摘要 |
PURPOSE:To get rid of a defect in a product in time of metalforming by a press, by making the minimum opening width of each fine slit and vertical bridge width between fine slits at both sides of a horizontal shaft differ from that of these fine slits at the central part side, in case of a slot mask provided with a lot of fine slits in rectangular form. CONSTITUTION:A slot mask 5 formed in rectangular externals carrying a lot of rectangular fine slits 9 at the specified intervals is disposed on a phosphor screen 2 of a panel 1a. In addition, the slot mask 5 is molded by means of press forming in a way that makes width W2 of a vertical bridge 10 between fine slits 9 at both sides of its horizontal shaft X larger than width W1 of the vertical bridge between fine slits 9 positioned at the central part side and that makes minimum opening width D2 of each fine slit 9 at the end part smaller than opening width D1 at the central part side. Therefore, a crack in the vertical bridge 10 in time of press work can be obviated while an extension of the minimum opening width D2 of each line slit 9 is no longer increased beyond the opening width D1 and a failure in press work can shrink to nothing; thus color slippage can be lessened. |
