| 摘要 |
PROBLEM TO BE SOLVED: To provide an illumination device capable of improving precision of the target luminance of which the setting is automatically updated by a simple method. SOLUTION: This device is equipped with an illumination fixture 2 having a fluorescent lamp 2b and a lighting circuit 2c to light on or off this fluorescent lamp 2b lighting controllably; a luminance sensor 3 to detect luminance of an irradiated face of this illumination fixture 2; and a control device having a dimming degree control part to control the dimming degree of a light source so that detected luminance of the luminance sensor become a preset target luminance, and a target luminance updating part to forcibly control the light source at the maximum degree of dimming for a prescribed period when the dimming degree continued at a prescribed value or more for a prescribed time, and to update the detected luminance of the luminance sensor at that time as a target luminance after re-lighting. COPYRIGHT: (C)2010,JPO&INPIT
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