MAGNETIC SUBSTANCE DETECTION DEVICE

摘要

A magnetic substance detection device includes elongated magnets and ferromagnetic thin film magnetoresistance elements. The magnets extend in parallel with a Y-axis direction and are magnetized opposite to each other in a Z-axis direction. The ferromagnetic thin film magnetoresistance elements have respective linear segments extending substantially along the Y-axis direction on a plane of a substrate disposed in a path of lines of magnetic force between the magnets and change their resistances in response to a change in a magnetic field directed in a direction orthogonal to the Y-axis direction in the plane of the substrate. The magnets apply bias magnetic fields lower in intensity than a saturated magnetic field of the ferromagnetic thin film magnetoresistance elements to the ferromagnetic thin film magnetoresistance elements, respectively, in the direction orthogonal to the Y-axis direction in the plane of the substrate.

主权项

1. A magnetic substance detection device for detecting a magnetic substance contained in an object to be verified which moves in a first direction, comprising:
an elongated first magnet and an elongated second magnet which extend in parallel with a second direction orthogonal to the first direction and are magnetized opposite to each other in a third direction orthogonal to the first and second directions; and a magnetic sensor having a ferromagnetic thin film magnetoresistance element which has a linear segment extending substantially along the second direction on a plane of a substrate disposed in a path of lines of magnetic force between the first magnet and the second magnet and changes resistance thereof in response to a change of a magnetic field directed in a direction orthogonal to the second direction in the plane of the substrate; the magnetic substance detection device being characterized in that the first magnet and the second magnet apply a bias magnetic field lower in intensity than a saturated magnetic field of the ferromagnetic thin film magnetoresistance element to the ferromagnetic thin film magnetoresistance element in the direction orthogonal to the second direction in the plane of the substrate.