Patent ID: 9234947
Filing Date: 2016-01-12
CPC Classification: G01R,G07D

Claim Text:
1. A magnetic sensor device, comprising: a housing that includes a first slit, which is an insert opening for a test object, a hollow section, which is a conveyance path for the test object that has been inserted through the first slit, and a second slit, which is an output opening for the test object that was conveyed through the hollow section; a first magnet that is provided in the hollow section and that is arranged such that magnetic poles thereof alternate along a conveyance direction of the test object; a second magnet that is provided in the hollow section in a position that faces the first magnet on an opposite side of the conveyance path, and having magnetic poles arranged along the conveyance direction in an opposite polarity to the magnetic poles of the first magnet, the first and second magnets forming a continuous gradient magnetic field along the conveyance direction; a magnetoresistive element provided between the test object and the first magnet and that has an output terminal, the magnetoresistive element being configured to change a resistance value thereof based on a magnetic component of the test object that passes through the gradient magnetic field; a substrate that encloses the magnetoresistive element and outputs the change in resistance value from the output terminal of the magnetoresistive element; and an electrical connector that electrically connects a pad of the substrate and the output terminal of the magnetoresistive element; wherein the magnetoresistive element is provided in an area where the magnetic field intensity is weak, which is where the magnetic field intensity in the gradient magnetic field is near zero; and the test object passes through an area where the magnetic field intensity of the gradient magnetic field is stronger than the area where the magnetic field intensity is weak.