| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a foreign matter detection system that is compact, inexpensive, and small in power consumption, and can perform remote communication. <P>SOLUTION: A foreign matter detection system 100 includes a foreign matter sensor 200 having an antenna 204 and a resistance element 206 electrically connected onto a surface of a reflection tag 202; and a detection device 300 including an antenna 302, a radio wave transmission part 304 which transmits radio waves of first and second frequencies from the antenna 302, a storage part 308 which stores reflection electric power values of first and second reflected waves as reflected waves of the first and second frequencies transmitted from the radio wave transmission part 304 in a reference state in which there is no foreign matter at a periphery of the foreign matter sensor 200, and a determination part 306 which determines that there is foreign matter at the periphery of the foreign matter sensor when a first difference and a second difference obtained by subtracting the reflection electric power values of the first and second reflected waves from third and fourth reflected waves as reflected waves of the radio waves of the first and second frequencies transmitted from the radio wave transmission part 304 are different in sign. <P>COPYRIGHT: (C)2012,JPO&INPIT |
