Magnetic sensor device

Patent metadata

Field	Value
Publication number	US-10353021-B2
Application number	US-201515327792-A
Country	US
Kind code	B2
Filing date	Jul 24, 2015
Priority date	Jul 25, 2014
Publication date	Jul 16, 2019
Grant date	Jul 16, 2019

Abstract

A magnetic sensor device includes: a magnetic field generator, disposed at one surface side of a sheet-like to-be-detected object including a magnetic component, to generate an intersecting magnetic field intersecting the object; and a magnetoresistive effect element disposed between the object and the magnetic field generator, having a resistance value changing in accordance with change of a component of the intersecting magnetic field in a conveyance direction along which the object is conveyed, when the object is conveyed. The magnetoresistive effect element includes resistive elements adjacent to each other in the conveyance direction and interconnected by a bridge, disposed in linear symmetry relative to an axis perpendicular to the conveyance direction and extending through a center of the bridge. A position in the conveyance direction of the bridge center of the magnetoresistive effect element coincides with a position in the conveyance direction of the magnetic field generator center.

First claim

The invention claimed is:

1. A magnetic sensor device comprising:
a magnetic field generator, disposed at one surface side of a sheet-like to-be-detected object including a magnetic component, to generate an intersecting magnetic field intersecting the to-be-detected object; and
a magnetoresistive effect element disposed between the to-be-detected object and the magnetic field generator, and having a resistance value that changes in accordance with change of a component of the intersecting magnetic field in a conveyance direction along which the to-be-detected object is conveyed, the change occurring when the to-be-detected object is conveyed in the conveyance direction, wherein
the magnetic field generator is a magnet having a first pole and a second pole in contact and adjacent to each other in a direction normal to the conveyance direction,
the magnetoresistive effect element comprises a first resistive element and a second resistive element adjacent to each other in the conveyance direction and interconnected by a bridge, a conveyance-direction center of a gap between the first resistive element and the second resistive element being disposed at the conveyance-direction center of the magnetic field generator, one end of the first resistive element being connected in common with one end of the second resistive element to form a bridge connection, the first resistive element and the second resistive element being disposed in linear symmetry relative to an axis perpendicular to the conveyance direction and extending through a center of the bridge, a position in the conveyance direction of the center of the bridge of the magnetoresistive effect element coinciding with a position in the conveyance direction of the center of the magnetic field generator,
a gap between the first resistive element and the second resistive element increases from the one end of the first resistive element and the second resistive element toward another end of the first resistive element and the second resistive element in a direction perpendicular to the conveyance direction, and
a bias magnetic field due to the first and second pole of the magnet is applied in a first direction along the conveyance direction to the first resistive element, and a bias magnetic field due to the first and second pole of the magnet is applied in a second direction along the conveyance direction to the second resistive element, the first direction being opposite to the second direction.

2. The magnetic sensor device according to claim 1 , wherein
the magnetic field generator further comprises a yoke disposed at an upper surface side of the magnet and between the magnet and the magnetoresistive effect element, the yoke comprising a soft magnetic body.

3. The magnetic sensor device according to claim 1 , further comprising a carrier disposed between the magnetic field generator and the magnetoresistive effect element, the carrier comprising a non-magnetic body.

4. The magnetic sensor device according to claim 1 , wherein
the first resistive element and the second resistive element of the magnetoresistive effect element are disposed in an array pattern as two rows having axes oriented in a direction perpendicular to the conveyance direction.

5. The magnetic sensor device according to claim 1 , wherein
another end of the first resistive element is connected to a voltage source, and
another end of the second resistive element is grounded,
to output voltage change of the bridge connection between the one end of the first resistive element and the one end of the second resistive element.

Assignees

• Mitsubishi Electric Corp

Inventors

• Ogomi Tomokazu
• Shimohata Kenji
• Asano Hiroyuki
• Inoue Jin

Classifications

• G01R33/096 Primary

  anisotropic magnetoresistance sensors · CPC title

• G07D7/04

  Testing magnetic properties of the materials thereof, e.g. by detection of magnetic imprint (G07D7/01 takes precedence) · CPC title

• G01R33/091

  Constructional adaptation of the sensor to specific applications · CPC title

• G01R33/098

  comprising tunnel junctions, e.g. tunnel magnetoresistance sensors · CPC title

• G01R33/093 Primary

  using multilayer structures, e.g. giant magnetoresistance sensors (thin magnetic films H01F10/00) · CPC title