Magnetic sensor device

摘要

A magnetic sensor device includes a first magnet and a second magnet that are disposed on mutually opposing sides of a conveyance path, and one of poles of the first magnet faces an opposite pole of the second magnet. The first magnet and the second magnet generate a cross magnetic field whose strength in a spacing direction, which is orthogonal to a conveying direction, is within a predetermined range. An AMR element is located in a magnetic field in which the strength of the cross magnetic field in the spacing direction is within a predetermined range, and detects, as change in a resistance value, change in the cross magnetic field caused by an object to be detected. A multilayer board outputs the change in the resistance value detected by the AMR element to a processing circuit.

主权项

1. A magnetic sensor device comprising:
a conveyance path for conveying an object to be detected having a magnetic pattern; a magnet having poles each facing the conveyance path; first magnetic bodies each in contact with each of side surfaces orthogonal to the conveying direction of the object to be detected, of side surfaces of the magnet; at least one second magnetic body located on a side opposite to the first magnetic bodies with respect to the conveyance path; a magnetoresistance effect element located between the second magnetic body and the conveyance path in a cross magnetic field that has magnetic field strength within a predetermined range in a spacing direction and that is generated by the first magnetic bodies and the second magnetic body, the magnetoresistance effect element to detect, as change in the resistance value, change in a component in the conveying direction in the cross magnetic field, the change being caused by the magnetic pattern of the object to be detected, the spacing direction being a direction orthogonal to the conveying direction in the conveyance path and being a direction that vertically passes through the magnetic pattern; and an outputter connected to the magnetoresistance effect element, the outputter to output the change in the resistance value detected by the magnetoresistance effect element.