| 摘要 |
PURPOSE:To considerably improve the ratio between upper and lower phosphor films and to improve the brightness, by performing the drying while lowering the temperature at the halfway of drying in the drying process employing the hot wind of water soluble phosphor suspension. CONSTITUTION:For 1/4hr, for example, from the start of drying, hot wind of 85-90 deg.C is provided while for remaining 3/4hr hot wind of 45-50 deg.C is provided into a glass tube having inner face coated with water soluble phosphor suspension to perform the drying. Consequently the drying speed of the suspention coated at the lower end of the inner face of the glass tube is suppressed to bring the ratio between upper and lower films near to 1.0, thereby the electrode at the inside of the glass tube end doesn't become transparent from the exterior resulting in the improvement of the brightness. |
