LIGHTING SYSTEM, AND PROTECTION METHOD OF HOT-CATHODE FLUORESCENT TUBE

PROBLEM TO BE SOLVED: To provide a lighting system capable of detecting trouble of a filament electrode without newly adding a component, and of protecting a hot-cathode fluorescent tube in detecting the trouble. SOLUTION: In protecting the hot-cathode fluorescent tube 10 in this lighting system lighting the hot-cathode fluorescent tube 10 having filament electrodes 11 and 12 by applying an A.C. high voltage thereto, a preheating voltage to the filament electrodes is generated and applied to the filament electrodes; the preheating voltage to the filament electrodes is detected; when the detected voltage is lower than a preset first reference voltage, the preheating voltage application and the high voltage application to the filament electrodes are stopped; and when the detected voltage is higher than a preset second reference voltage, the high voltage application to the filament electrodes is stopped. COPYRIGHT: (C)2008,JPO&INPIT