| 摘要 |
PURPOSE:To increase both the brightness and contrast of a fluorescent surface for a color-picture tube, by forming phosphor layers with pigments on the inner surface of a panel, and forming phosphor layers without any pigment on the former phosphor layers. CONSTITUTION:A blue phosphor which has a large grain diameter and is coated with a pigment, and a blue phosphor which has a small grain diameter and is not coated with any pigment are suspended in a PVA solution containing a small amount of a dichromate, thereby a blue phosphor slurry being prepared. Thus prepared phosphor slurry is injected on the inner surface of a glass panel 1 to form a photosensitive film, before the film is exposed and developed, thereby a blue phosphor layer 6b being obtained. After that, a red and a green phosphor layer 6r and 6g are formed by subsequent similar processes. Here, phosphor layers 6' with pigments are formed on the side of the inner surface of the panel 1, while phosphor layers 6'' without any pigment are formed over the layers 6', since the sedimentation velocities of the phosphors vary according to their grain diameters. Consequently, the layers 6' reduce the reflectance of external light, and thereby the contrast of a fluorescent surface for a color-picture tube is increased. Besides, the layers 6'' increase the brightness of the fluorescent surface. |
