| 摘要 |
The shadow mask equipped for a shadow mask type color cathode ray tube of this invention is placed in order to face in the inside of panel portion having a fluorescent screen. The original plate with a porous portion of substantially rectangle state which establish a large number of electron beam passage holes is pressed is shaped. The diameter of the electron beam passage holes is smaller in the four corner regions than the center region of the porous portion. The width of the bridge which connects electron beam passage holes which adjoins for the oblique direction is bigger in four corner regions than the center region of porous portion. Therefore, the strength of the corner region of porous portion rises, as compared to the prior art, as it is close to the corner edge. As the result, the extension deformation of the aperture is suppressed, even if the considerably big transformability is applied in dot state electron beam passage holes in the corner region in composing the shadow mask unitedly by press shaping.
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