| 摘要 |
PURPOSE:To save the electric power consumption of a fluorescent lamp, by providing a life detecting member which is able to detect the lamp life by being deteriorated with ultra violet ray energy at a speed faster than the fluorescent material. CONSTITUTION:A fluorescent material layer 4 for detecting the life is formed on the inner surface of a glass tube 1 at one end thereof. The remaining inner surface of the glass tube 1 is coated with a usual fluorescent material layer 5 such as calcium halophosphate. As the fluorescent material layer 4 for detecting the liefe, is used one that is deteriorated by ultra violet ray faster than the usual fluorescent material layer 5. The life of the fluorescent lamp is predicted by a deterioration period of the fluorescent material layer 4, so that the life of the lamp can be known beforehand visually by the deterioration of the fluorescent material layer 4. |
