| 摘要 |
PURPOSE:To effectively reduce doming by providing a slender groove in a Y direction in a shadow portion where a relationship Kx<Ky between the curvature Kx in an X direction and the curvature Ky in a Y direction of the shadow mask. CONSTITUTION:A groove 25 in a shadow portion 24 is a slender and thin portion which is provided in a Y direcrion in the substantial center of the shadow portion 24 extending in a Y direction, and the width of the groove is formed to about 2/3-1/4 of the width of the shadow portion at the opening portion, and the depth of the groove is formed to about 3/4-1/4 of the original thickness. Whereby, sigmaY of the strength characteristic in a Y direction becomes larger in a ratio. Accordingly, if the curvature satisfies the relation Kx<Ky, it is possible to enlarge the equivalent curvature K thereby and therefore it is possible to reduce doming. |
