Magnetic sensor

Patent metadata

Field	Value
Publication number	US-11209503-B2
Application number	US-201916665185-A
Country	US
Kind code	B2
Filing date	Oct 28, 2019
Priority date	Mar 24, 2017
Publication date	Dec 28, 2021
Grant date	Dec 28, 2021

Abstract

The magnetic sensor can prevent an increase of a positional detection error of a subject/object even in the case of applying an external magnetic field with a magnetic field intensity exceeding a predetermined range. A magnetic sensor is equipped with a magnetoresistive effect element (MR element) 11 that can detect an external magnetic field and a soft magnetic body shield 12 . The soft magnetic body shield(s) 12 are/is positioned above and/or below the MR element 11 in a side view, and the size of the MR element 11 is physically included within a perimeter of the soft magnetic body shield 12.

First claim

What is claimed is:

1. A magnetic sensor, comprising:
a plurality of magnetoresistive effect elements (MR elements), which can detect an external magnetic field, and
a plurality of soft magnetic body shields, wherein
the plurality of MR elements and the plurality of soft magnetic body shields configure a lamination film structure,
the soft magnetic body shields are positioned above and/or below the plurality of MR elements in a side view, respectively,
the size of each of the MR elements is physically included within a perimeter of each of the soft magnetic body shields in a plan view, and
the plurality of the MR elements is two-dimensionally arranged in an array.

2. The magnetic sensor according to claim 1 , wherein all intervals between adjacent MR elements are the same.

3. The magnetic sensor according to claim 1 , wherein a shape of each of the soft magnetic body shields in the plan view is nearly circular.

4. The magnetic sensor according to claim 1 , wherein a shape of each of the soft magnetic body shields in the plan view is an N-sided polygon (N is 6 or greater even number).

5. The magnetic sensor according to claim 1 , wherein each of the soft magnetic body shields is columnar.

6. The magnetic sensor according to claim 1 , wherein each of the soft magnetic body shields is conical.

7. The magnetic sensor according to claim 1 , wherein each of the soft magnetic body shields includes a first ridge line, and a second ridge line and a third ridge line that are inclined with respect to the first ridge line in the side view,
the first ridge line is parallel to the arrangement direction of the plurality of MR elements, and
the second ridge line and the third ridge line are non-parallel to each other.

8. The magnetic sensor according to claim 1 , wherein each of the soft magnetic body shields includes a columnar portion that comprises a first surface and a second surface, wherein the second surface faces the first surface, and a convexity, which protrudes from the first surface of the columnar portion and is positioned to allow the second surface to face the MR element.

9. The magnetic sensor according to claim 1 , wherein each of the soft magnetic body shields includes a columnar portion that comprises a first surface and a second surface, wherein the second surface faces the first surface, and a concave portion, which is formed on the first surface of the columnar portion and is positioned to allow the second surface to face the MR element.

10. The magnetic sensor according to claim 1 , wherein each of the soft magnetic body shields includes a columnar portion that comprises a first surface and a second surface, wherein the second surface faces the first surface, and a concave portion, which is formed on the first surface of the columnar portion.

11. The magnetic sensor according to claim 1 , wherein each of the soft magnetic body shields comprises a through-hole that penetrates through the soft magnetic body shield in a thickness direction.

12. The magnetic sensor according to claim 1 , wherein a diameter φs of each of the soft magnetic body shields and a diameter φm of each of the MR elements fulfill a relationship in a following formula (1):
φ s≥ 1.3φ m   (1).

13. The magnetic sensor according to claim 1 , wherein thickness h of each of the soft magnetic body shields and a diameter φm of each of the MR elements fulfill a relationship in a following formula (2):
h> 0.3φ m   (2).

14. The magnetic sensor according to claim 1 , wherein a harmonic component V 3rd , which is output in the case of applying the external magnetic field with a magnetic field intensity that exceeds 70 mT to the MR elements, and the harmonic component V 3rd , which is output in the case of applying the external magnetic field with 70 mT or less of a magnetic field intensity to the MR elements, are the same.

15. The magnetic sensor according to claim 1 , wherein a diameter φs, of each of the soft magnetic body shields is 2.00 to 2.75 times a diameter φm of the corresponding MR element.

Assignees

• Tdk Corp

Inventors

• Uchida Keisuke
• Hirabayashi Hiraku

Classifications

• G01B7/02

  for measuring length, width or thickness (G01B7/004, G01B7/12 take precedence) · CPC title

• H01F3/00

  Cores, Yokes, or armatures (magnetic materials H01F1/00; permanent magnets H01F7/02) · CPC title

• G01R33/093

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

• H01F10/3268

  the exchange coupling being asymmetric, e.g. by use of additional pinning, by using antiferromagnetic or ferromagnetic coupling interface, i.e. so-called spin-valve [SV] structure, e.g. NiFe/Cu/NiFe/FeMn · CPC title

• G01R33/091 Primary

  Constructional adaptation of the sensor to specific applications · CPC title