FILAMENT BREAK DETECTION METHOD AND DEVICE, DISCHARGE LAMP LIGHTING DEVICE, AND LIGHTING FIXTURE

PROBLEM TO BE SOLVED: To provide a filament break detection method, a filament break detection device, a discharge lamp lighting device, and a lighting fixture. SOLUTION: When a filament of a discharge lamp DL equipped with a pair of filament electrodes E1, E2 is broken, the filament break is detected by detecting direct-current voltage between power-source side terminals and/or non-power-source side terminals between the pair of filament electrodes. The discharge lamp lighting device includes a discharge lamp; an electronic lighting circuit EOC for biasing it and equipped with a protective movement function; and a direct-current voltage detecting circuit DCD for detecting direct-current voltage existing between the power-source side terminals and/or non-power-source terminals between the pair of filament electrodes when the filaments are broken and detecting the filament break to make the electronic lighting circuit carry out the protective movement function. COPYRIGHT: (C)2006,JPO&NCIPI