| 摘要 |
PURPOSE:To obtain a picture image, which causes less reflection of external light, has a good constrst and is especially suitable for a display tube for a data terminal, by applying a phosphor, which contains pigment particles having above 2.5 times the specific gravity of the phosphor unevenly adhering to the surfaces of phosphor particles, by a precipitation method. CONSTITUTION:After a phosphor suspension 2 is poured into a glass bubl 1, the suspension 2 is left to stand so as to make phosphor particles 3 to deposit over the inner wall of the bulb 2. During the precipitation, the phosphor particles 3 deposit, with many pigment particles 4 having a large specific gravity adhering to the lower side of each particle 3. Thus, a phosphor film the glass panel 11 side of which contains a large amount of pigment particles 4, and the upper side of which, irradiated by electron rays, contains a small amount of pigment particles 4 is formed. As a result, a fluorescent screen the glass panel 11 side, the observer's side, of which has a high pigment density and the inner side, the electron-ray irradiated side, of which has a low pigment density can be obtained. Consequently, a fluorescent screen for a Braun tube, which produces a picture image with a good contrast without extremely deteriorating the luminous efficiency, can be obtained. |
