| 摘要 |
PROBLEM TO BE SOLVED: To reduce replacement cost of a fluorescent lamp by judging a deterioration condition of the lamp before the lamp reaches a flickering state objectively and enabling its replace when the lamp achieves its maximum service life. SOLUTION: Light of a fluorescent lamp 5 is converged by a converging device 6 and is sent to a light projecting device 8 through an optical fiber cable 7. The light sent to the light projecting device 8 is projected to an illuminance detector 9, and the illuminance detector 9 detects illuminance of light which is projected. A comparator 10 compares a service life management illuminance reference value which is input in advance with illuminance of the fluorescent lamp 5 which is detected. If illuminance of the fluorescent lamp 5 is below the service life management illuminance reference value, a light emitting diode 11 for display is lit by an output from the comparator 1. Consequently, it is possible to judge a deterioration condition of the lamp before the fluorescent lamp 5 reaches a flickering condition objectively and replace the lamp when the fluorescent lamp 5 achieves the maximum service life so that replacement cost of the fluorescent lamp 5 is reduced. |
