# US 12,215,988 B2 · Position detection device

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- Number: US 12,215,988 B2
- Document ID: US12215988B2
- Status: Granted
- Kind: B2
- Application number: 18/404,023
- Filed: 2024-01-04
- Published: 2024-04-25
- Granted: 2025-02-04
- Earliest claimed: 2019-06-05
- Assignees: TDK Corporation
- Applicants: TDK Corporation
- Inventors: Keisuke Uchida; Yongfu Cai
- Web page: https://patentgrep.com/patent/US12215988B2

## CPC

- G01D 5/145: {influenced by the relative movement between the Hall device and magnetic fields (see G01R33/06)}
- G01D 5/16: by varying resistance
- G01D 3/08: with provision for safeguarding the apparatus, e.g. against abnormal operation, against breakdown
- G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR

## Abstract

A position detection device includes a magnet that generates a magnetic field to be detected, and a magnetic sensor. The magnetic sensor detects the magnetic field to be detected and generates a detection value corresponding to the position of the magnet. The magnetic field to be detected has a first direction that changes within a first plane, at a reference position in the first plane. The magnetic sensor includes four MR elements. Each of the MR elements includes a first magnetic layer having first magnetization that can change in direction within a second plane corresponding to the each of the MR elements. The first plane and the second plane intersect at a dihedral angle α other than 90°. A detection value depends on the direction of the first magnetization.

## Claims

### Claim 1

A position detection device comprising:
a magnetic field generator configured to generate a magnetic field to be detected having a first direction at a reference position within a first plane; and
a magnetic sensor configured to detect the magnetic field to be detected and generate a detection value corresponding to a relative position of the magnetic field generator with respect to the magnetic sensor, the magnetic sensor including:
a magnetoresistive element including a first magnetic layer having first magnetization that can change in direction within a second plane corresponding to the magnetoresistive element, the second plane being oblique to the first plane, the magnetic field to be detected received by the magnetoresistive element including an in-plane component parallel to the second plane, the in-plane component having a second direction that changes with a change in the first direction, the first magnetic layer being configured such that the direction of the first magnetization changes with a change in the second direction, and the detection value depending on the direction of the first magnetization, wherein
the magnetic field generator and the magnetic sensor are configured such that as the relative position of the magnetic field generator with respect to the magnetic sensor changes, the first direction changes within a predetermined variable range in the first plane,
the magnetic sensor further includes a substrate that supports the magnetoresistive element,
the substrate includes a main surface, and
the second plane is oblique to each of the first plane and the main surface.

### Claim 2 (depends on 1)

The position detection device according to claim 1, wherein:
the substrate further includes a slope oblique to the main surface;
the magnetoresistive element is located on the slope; and
the second plane is parallel to the slope.

### Claim 3 (depends on 1)

The position detection device according to claim 1, wherein:
the magnetic field generator is a magnet; and
the relative position of the magnetic field generator with respect to the magnetic sensor can change so that a predetermined point in the magnet moves within a linear range of movement.

### Claim 4 (depends on 3)

The position detection device according to claim 3, wherein the range of movement is represented by a line segment parallel to the main surface.

### Claim 5 (depends on 4)

The position detection device according to claim 4, wherein a center point in the range of movement falls on a virtual line that passes through the reference position and is perpendicular to the main surface.

### Claim 6 (depends on 3)

The position detection device according to claim 3, wherein the range of movement is represented by a line segment perpendicular to the main surface.

### Claim 7 (depends on 6)

The position detection device according to claim 6, wherein a center of gravity of the magnet is located at a position off a virtual line in a direction parallel to the main surface, the virtual line passing through the reference position and being perpendicular to the main surface.

### Claim 8 (depends on 3)

The position detection device according to claim 3, wherein the magnet is magnetized in a direction parallel to the first plane.

### Claim 9 (depends on 8)

The position detection device according to claim 8, wherein the magnet is magnetized in a direction parallel to the main surface.

### Claim 10 (depends on 8)

The position detection device according to claim 8, wherein the magnet is magnetized in a direction perpendicular to the main surface.