| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to detect the IDs of moving bodies and their respective positions on condition that the interval between adjacent moving bodies is larger than a certain limit by using a low-frequency electric field signal generating device and generating a burst signal of an infrared-ray signal or low-frequency electric field signal. SOLUTION: After only one burst light signal 25a is generated by a light emission device 24a, the generation is stopped. At this time, a tag 3 photodetects the burst signal 25a and a signal which is generated inside is '0' and changes back to '1' after the burst is ceased. When this signal is '0', the tag 3 generates a radio wave signal, which is received by a radio wave reception device outside the tag 3, thereby detecting the tag 3 being present in the light beam 25a. Similarly, a scan is made from the light emission device 24a to a device 24I one after another to detect the position of the tag 4. Even when there are more than one tags, their positions can be detected. |
