| 摘要 |
PROBLEM TO BE SOLVED: To trace a target on-road vehicle, to enlarge a communication area and to increase transmission information quantity by fitting a galvano mirror to a road side optical beacon device and controlling the projection angle of an optical beacon. SOLUTION: An optical signal is projected on an on-vehicle unit C for light projection/reception by the signal projection part 2 of an optical beacon device through a galvano mirror G having an optical scanning element which is biased in a two-dimensional direction by using a semiconductor process and which can realize reflection. A galvano mirror control part 1 changes the current and the frequency of the galvano mirror G and controls the communication direction. At a normal time, the galvano mirror G is controlled so that the signal is searched over a wider range. When the on-vehicle machine C is detected, the on-vehicle machine C is controlled to be traced. Tracing is linked and it is informed to a communication processing part 3. The signal projection part 2 starts communication. Thus, the range of a communication area can substantially be increased. Then, communication time is prolonged and communication information quantity can be increased. |
