| 摘要 |
PROBLEM TO BE SOLVED: To provide a light beacon device capable of using one light receiving element also for measuring brightness in addition to the reception of an optical signal. SOLUTION: An on-vehicle device 2 is provided with a light beacon head 3, a light beacon receiver 4, a navigation device 5, and a light control device 6. The head 3 includes a light receiving element for receiving an optical light and sunlight from a road device 1, an AC signal corresponding to the optical signal and a DC component corresponding to sunlight are extracted from the output of the light receiving element and transmitted to the receiver 4. The receiver 4 finds out road traffic information from the AC signal and displays the information on the display screen of the device 5. The device 5 receives the level of the DC component and controls the brightness of the display screen based upon the level of the DC component, i.e., the level of sunlight. The device 6 turns on/off various lamps based upon the level of the DC component. |
