LIGHTING DEVICE AND ILLUMINATING FIXTURE USING THE SAME

PROBLEM TO BE SOLVED: To provide a lighting device capable of reducing variation in brightness of respective light-emitting elements in dimming with low light flux, and of suppressing flicker when a light source part is seen through a video apparatus, and to provide an illuminating fixture using the...

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Bibliographische Detailangaben
Hauptverfasser: HIRAMATSU AKINORI, EZAKI SANA
Format: Patent
Sprache:eng
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Zusammenfassung:PROBLEM TO BE SOLVED: To provide a lighting device capable of reducing variation in brightness of respective light-emitting elements in dimming with low light flux, and of suppressing flicker when a light source part is seen through a video apparatus, and to provide an illuminating fixture using the same.SOLUTION: A lighting device has: a step-down chopper circuit 5 variably controlling an on pulse width of a switching element Q1 to step down a DC voltage; and a current adjustment circuit 50 adjusting an output current of the step-down chopper circuit 5 to variably control a load current flowing in a light source part 10. The current adjustment circuit 50 has: resistances R17 and R18 connected in parallel to the light source part 10 and dividing the output current of the step-down chopper circuit 5; a switching element Q2 connected in series to the resistances R17 and R18; and a controller 50A on-off controlling the switching element Q2. The controller 50A on-off controls the switching element Q2 in a region with deep dimming of the light source part 10.