LIGHTING SYSTEM UTILIZING EXTERNAL LIGHT

摘要

PROBLEM TO BE SOLVED: To keep illuminance of a lighting object unchanged even if external light fluctuates, in a lighting system utilizing external light.

SOLUTION: The lighting system utilizing external light 1 includes: a daylighting device 2 arranged near openings of a house and collects the external light; a light guide device 3 to perform light guiding of the collected light; an irradiation device 5 to irradiate the guided light to an irradiating object; a light-emitting device 6 to supplement the light of the irradiation device 5, by irradiation with supply of power; a brightness sensor 7 to measure brightness of the irradiating object; and a controlling device 8 to control an output of the light-emitting device 6 based on the measurement result of the brightness sensor 7 in order to keep the brightness of the irradiating object at a predetermined illuminance level. This keeps the illuminance at the irradiating object unchanged even if the external light fluctuates.

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