| 摘要 |
PURPOSE:To improve both luminous flux and luminous flux maintenance rate by applying a phosphor film to a film which is prepared by applying a specific amount of a liquid suspension prepared by dispersing a metal oxide powder in an aqueous solution of a water binder to the inner surface of a glass tube. CONSTITUTION:After the inner surface of a glass tube 1 is washed with water, the washed inner surface is coated with an alumina film 2 by applying a liquid alumina suspension which is prepared by dispersing 0.5-3% of gamma-alumina in an aqueous solution containing about 0.05-0.5% of polyethylene oxide. The amount of alumina in the alumina film 2 is adjusted to 0.02-0.1mg/cm<2>. If the amount of alumina in the alumina film 2 is less than 0.02mg/cm<2>, only small improvement of luminous flux is achieved. If the amount of alumina in the alumina film 2 is greater than 0.1mg/cm<2>, the tube can be curved with difficulty and luminous flux and luminous flux maintenance rate become rather deteriorated. Next, a phosphor film 3 is applied to the thin alumina film 2. After that, a circular fluorescent lamp is completed through a usual process.
|
