| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a vehicle detector that synchronizes projection and reception light by optical communication so as to obviate the need of a synchronization cable. <P>SOLUTION: This vehicle detector 100 includes a light projector S6 and a light receiver S7 for receiving infrared light output from the light projector S6. The vehicle detector 100 detects presence or absence of a vehicle passing through a portion between the light projector S6 and the light receiver S7. The light projector S6 and the light receiver S7 of the vehicle detector 100 perform a vehicle detection operation in a time zone in which projection and reception light by a light projection element S6n-1 and a light reception element S7-1 that perform synchronization of the projection and reception, is completed. In addition, by using coded infrared light 9 obtained by coding infrared light for synchronization, the light receiver S7 performs the detection operation only in a time zone in which the specific coded infrared light 9 is received by a light reception element S7n-1 for synchronization. Accordingly, it is possible to prevent erroneous synchronization due to interference of light. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
