| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a device for controlling light emission from a light-emitting diode in a simple circuit structure on the basis of brightness of the surroundings. <P>SOLUTION: One or a plurality of visible-light light-emitting diodes 120 are functioned as a lighting tool, and the current for driving the light-emitting diodes is supplied from a driver amplifier 136 for illumination of the light-emitting diode. The current flowed in the driver amplifier 136 for illumination of the light-emitting diode is controlled by a dimming control signal L transmitted from a dimming circuit 110, and adjustment for brightness of the light-emitting diode is carried out by performing pulse width modulation (PWM) to the dimming control signal L. The light-emitting diode is used as a light-receiving sensor at the period when the current flowing in the light-emitting diode becomes zero since a period when current flowing in the light-emitting diode exists and a period when the current flowing in the light-emitting diode does not exist alternately exist in the pulse width modulation. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
