| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a magnetic object detector capable of detecting and announcing even a small magnetic object, using a magnetic sensor for detecting the change of magnetic flux density caused by the invasion of a magnetic object with no saturation even under a strong magnetic flux density environment, as an alarming means for the invasion of the magnetic object into a room where a strong magnet of a MRI diagnosis instrument and the like are placed. <P>SOLUTION: The magnetic object detector comprises: a magnetic sensor detecting magnetic flux density; a threshold; a comparing function comparing the output of the magnetic sensor with the threshold; and an announcing function announcing the result of the comparing function. With setting the solid angle between the detecting axis and the perpendicular axis or the horizontal axis in the magnetic sensor within 15°, direct current magnetic flux density applied to the detecting axis is reduced, and using a high resolution magnetic sensor having narrow input tolerance region, a small change in magnetic flux density caused by the invasion of a small magnetic object is detectable. <P>COPYRIGHT: (C)2009,JPO&INPIT |
