Magnetic field sensor head and method for manufacturing same

Patent metadata

Field	Value
Publication number	US-12360180-B2
Application number	US-202118037203-A
Country	US
Kind code	B2
Filing date	Sep 10, 2021
Priority date	Nov 19, 2020
Publication date	Jul 15, 2025
Grant date	Jul 15, 2025

Abstract

A magnetic field sensor head includes an optical fiber, a GI fiber whose one end is optically connected to the optical fiber, a magnetic film joined to the other end of the GI fiber, a reflection film joined to a surface of the magnetic film opposite to a surface joined to the magnetic film, and a support member joined to a surface of the reflection film opposite to the surface joined to the magnetic film.

First claim

What is claimed is:

1. A magnetic field sensor head comprising:
an optical fiber;
a GI fiber whose one end is optically connected to the optical fiber;
a magnetic film joined to the other end of the GI fiber;
a reflection film joined to a surface of the magnetic film opposite to a surface joined to the magnetic film; and
a support member joined to a surface of the reflection film opposite to the surface joined to the magnetic film, and forming a rod-shaped member at one end together with the magnetic film and the reflection film.

2. The magnetic field sensor head according to claim 1 , wherein
the cladding diameter of the GI fiber is the same as the cladding diameter of the optical fiber.

3. The magnetic field sensor head according to claim 2 , wherein
the rod-shaped member has a square columnar rod-shaped member having square-shaped bottom surfaces, one of the bottom surfaces is the surface of the magnetic film joined to the GI fiber, and the other of the bottom surfaces is a surface opposite to the surface of the support member joined to the reflection film.

4. The magnetic field sensor head according to claim 3 , wherein
the magnetic film is a rare earth iron garnet.

5. The magnetic field sensor head according to claim 4 , wherein
the length of one side of the surface of the magnetic film is equal to or more than 20 μm, and is equal to or less than the cladding diameter of the GI fiber.

6. The magnetic field sensor head according to claim 5 , wherein
the length of the diagonal of the surface of the magnetic film is equal to or less than the cladding diameter of the GI fiber.

7. The magnetic field sensor head according to claim 5 , wherein
the beam diameter of light introduced from the GI fiber to the reflection film is equal to or more than 20 μm, and is equal to or less than the length of one side of the reflection film.

8. A manufacturing method of a magnetic field sensor head comprising:
melt bonding one end of an optical fiber to one end of a GI fiber; and
adhering a square-shaped bottom surface of a square columnar rod-shaped member having a support member on which a reflection film and magnetic film are formed, by adherence to the other end of the GI fiber, wherein
the length of one side of the bottom surface of the magnetic film is equal to or more than 20 μm, and is equal to or less than the cladding diameter of the GI fiber.

9. The manufacturing method according to claim 8 , wherein
the length of one side of the surface of the magnetic film is equal to or less than the cladding diameter of the GI fiber.

10. The manufacturing method according to claim 9 , further comprising:
forming a reflection layer on a base member;
forming a magnetic layer on the magnetic reflection layer;
forming the rod-shaped member with one end of the rod-shaped member bonded to the base member by half dicing the base member on which the reflection layer and magnetic layer are formed so that the magnetic layer has a square-shape; and
cutting the rod-shaped member from the base member.

Assignees

• Citizen Finedevice Co Ltd
• Citizen Watch Co Ltd

Inventors

• Miyamoto Mitsunori
• Kubo Toshiya

Classifications

• G01R33/0052

  Manufacturing aspects; Manufacturing of single devices, i.e. of semiconductor magnetic sensor chips (devices based on galvano-magnetic effect or the like H10N50/85) · CPC title

• G02B6/024

  with polarisation maintaining properties · CPC title

• G01R33/0322 Primary

  using the Faraday or Voigt effect · CPC title