| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce the size of a permanent magnet while ensuring the detection sensitivity. <P>SOLUTION: The detector has a magnetic guide 4 disposed near a magnetic sensor 30 (a position facing to a permanent magnet 1 being interposed by the magnetic sensor 30). With this, compared with a conventional detector having no magnetic guide 4, the magnetic flux crossing a detecting plane of the magnetic sensor 30 is increased (larger magnetic flux density). As a result, even when a permanent magnet 1 of a size smaller than a conventional magnet (a weaker magnetic field), the detection sensitivity same as the conventional magnet is ensured. Since the detector has the magnetic guide 4 for guiding the magnetic flux of the permanent magnet 1 to a magnetic detection part 3, the size of the permanent magnet 1 can be reduced while ensuring the detection sensitivity. <P>COPYRIGHT: (C)2013,JPO&INPIT |
