MAGNETIC SENSOR

• US 20150192432A1
• Filed: 01/08/2015
• Published: 07/09/2015
• Est. Priority Date: 01/08/2014
• Status: Active Grant

• Current Assignee: Alps Alpine Co., Ltd.
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Noguchi, Takafumi, Nakamura, Tokuo, Umetsu, Eiji, Ando, Hideto, Sejimo, Kazushige, Endo, Hiroaki
• Granted Patent: US 9,644,994 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06
• CPC Class Codes: G01R 33/09 Magnetoresistive devices

Abstract

A magnetic sensor for detecting the position of a magnet in an X direction includes two magnetic sensor elements which are disposed to be spaced apart from each other in a Y direction and are disposed to face the magnet in a Z direction, in which a soft magnetic body is provided to be located between the magnet and the two magnetic sensor elements and to be located between the two magnetic sensor elements, the two magnetic sensor elements are provided in a range in which magnetic flux which is generated from the magnet saturates magnetization of free magnetic layers of the two magnetic sensor elements, magnetization directions of fixed magnetic layers of the two magnetic sensor elements are the same as each other, and a bridge circuit is configured with the two magnetic sensor elements.

Claims

1. A magnetic sensor for detecting a position of a magnet in a first direction, comprising:

a magnet magnetized in the first direction; and

two magnetic sensor elements,

wherein the two magnetic sensor elements are spaced apart from each other in a second direction orthogonal to the first direction and face the magnet in a third direction orthogonal to the first direction and the second direction,

a soft magnetic body is provided between the magnet and the two magnetic sensor elements in the third direction and located between the two magnetic sensor elements in the second direction,

the two magnetic sensor elements each have a fixed magnetic layer in which magnetization is fixed, and a free magnetic layer in which magnetization changes due to an external magnetic field, and are provided in a range in which magnetic flux which is generated from the magnet saturates magnetization of the free magnetic layers of the two magnetic sensor elements,

wherein magnetization directions of the fixed magnetic layers of the two magnetic sensor elements are the same as each other, and

a bridge circuit is configured with the two magnetic sensor elements.

2. The magnetic sensor according to claim 1, wherein the two magnetic sensor elements and the soft magnetic body extend in the first direction, and all of the magnetization directions of the fixed magnetic layers of the two magnetic sensor elements are directed in the second direction.

3. The magnetic sensor according to claim 1, wherein the soft magnetic body has end portions opposite to each other in the third direction, and

the end portion which is located on the sides of the two magnetic sensor elements is disposed to overlap with a portion of each of the two magnetic sensor elements.

4. The magnetic sensor according to claim 3, wherein a center in a width direction of the magnetic sensor element is located further to the outside than the soft magnetic body.

5. The magnetic sensor according to claim 1, further comprising:

two magnetic sensor elements,

wherein a full-bridge circuit is configured with the four magnetic sensor elements.

6. The magnetic sensor according to claim 1, wherein when viewed from the third direction, a sensor element group which includes the two magnetic sensor elements is provided at a position overlapping with the center of the magnet.