| 摘要 |
PURPOSE:To obtain a mechanically strong and less doming shadow mask by making the front and rear surface holes of the openings of a shadow mask equal in size. CONSTITUTION:A front surface hole 3a and a rear surface hole 3b are each made, for example, hemispherical and approximately equal in size. In this condition, when the thickness of a shadow mask plate, the radius of an opening 2, and the radius of the front surface hole 3a are fixed, theta can be made larger as compared to the case of an existing shadow mask, providing a tolerance to the occurrence of reflected electron beams and light exposure. When the radius of the opening 2, the radius of the front surface hole 3a, and theta are fixed, the shadow mask plate can be made thick and mechanically strong and the doming can be reduced; thus the picture quality can be improved. |
