| 摘要 |
PURPOSE:To enable forming phosphor with uniform dimension and size when phosphor paints being printed by making an opening inner wall of a shadow mask in sectional shape forming a curve having no broken point from a large opening part to a small opening part. CONSTITUTION:When an opening of shadow mask for high-resolution Braun tube is formed with etching, beginning with corroding a small opening part d, a coating material, which buries the concave thereof, is a little softened when a large opening part D being corroded. Resultantly, while the corrosion liquid advances to the bottom of the small opening concave and encroaches on the part near the bottom of the large opening part, an opening inner wall is made in the shape in which a broken point from the large opening part D to the small opening part d does not exist and the minimum opening part diameter do never becomes larger than the small opening part diameter d. Therefore, when the mask being used as a negative plate for exposure on printing phosphor paints, reflection of printing light can be removed, and the size and dimension of phosphor can be made exact and uniform. |
