| 摘要 |
<p>PROBLEM TO BE SOLVED: To light a nightfall auxiliary lamp 22 timely only during a nightfall period by controlling it so as to become hard to turn on and easy to turn off. SOLUTION: This controller 2, under the OFF condition of the nightfall auxiliary lamp 22, counts continuous ON duration when external illumination intensity is within a lighting illumination intensity range, and lights the nightfall auxiliary lamp 22 when the duration exceeds a prescribed reference period MAX, on the other hand, under the lighting condition, estimates the period when it is out of the lighting illumination intensity range, substrates the period when the external illumination intensity is within a lighting illumination intensity range therefrom, and turns out the nightfall auxiliary lamp 22 when an estimated result exceeds the base period MAX. It is thus possible to control an illuminating lamp so as to become hard to turn on when the external illuminating intensity changes from a brighter condition than lighting upper limit intensity to the lighting illumination intensity range, and easy to turn off when the external illuminating intensity changes from lighting illumination intensity range to a darker condition than lighting lower limit intensity.</p> |
