JP2022152036A - magnetic sensor - Google Patents

Abstract

To provide a magnetic sensor capable of detecting a magnetic flux in a minute region.SOLUTION: A magnetic sensor 1 includes: magnetic bodies 10, 20; and a magnetic detection part 30 for detecting a magnetic flux φ passing through between one end 11 of the magnetic body 10 and one end 21 of the magnetic body 20. The other end 12 of the magnetic body 10 and the other end 22 of the magnetic body 20 are brought close to each other to constitute a detection probe P. In this way, the magnetic flux of a minute region becomes possible to be detected since the tips of two magnetic bodies 10, 20 constitute the detection probe P.SELECTED DRAWING: Figure 1

Description

The present invention relates to a magnetic sensor, and more particularly to a magnetic sensor capable of detecting magnetic flux in a minute area.

Patent Literature 1 discloses a magnetic sensor in which detection sensitivity is enhanced by using a rod-shaped magnetic body to collect magnetic flux in a sensor chip.

Japanese Patent No. 6610178

However, since the magnetic sensor described in Patent Document 1 has sensitivity to magnetic flux in a relatively wide range, it was not easy to detect magnetic flux in a minute area.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a magnetic sensor capable of detecting magnetic flux in a minute area.

A magnetic sensor according to the present invention includes first and second magnetic bodies, and a magnetic detection section that detects magnetic flux passing between one end of the first magnetic body and one end of the second magnetic body, The other end of the magnetic body and the other end of the second magnetic body are characterized by being close to each other.

According to the present invention, since the tips of the two magnetic bodies constitute the detection probe, it is possible to detect the magnetic flux in a very small area.

In the present invention, the other end of the first magnetic body and the other end of the second magnetic body may be positioned on the same plane. This makes it easier to bring the detection probe closer to the flat surface of the object to be detected.

In the present invention, the first and second magnetic bodies may have a shape in which the cross-sectional area decreases toward the other end. According to this, it is possible to further miniaturize the detection probe.

In the present invention, the angle formed by the extending direction of the first magnetic body on the other end side and the extending direction of the second magnetic body on the other end side may be an obtuse angle. According to this, it is possible to collect the magnetic flux in the horizontal direction more efficiently.

Thus, according to the present invention, it is possible to provide a magnetic sensor capable of detecting magnetic flux in a minute area.

FIG. 1 is a schematic diagram for explaining the structure of a magnetic sensor 1 according to a first embodiment of the invention. FIG. 2 is a schematic diagram for explaining the structure of the magnetic sensor 2 according to the second embodiment of the invention. FIG. 3 is a schematic diagram for explaining the structure of the magnetic sensor 3 according to the third embodiment of the invention. FIG. 4 is a schematic perspective view for explaining the structure of a magnetic sensor 4 according to a fourth embodiment of the invention. FIG. 5 is a schematic exploded perspective view showing a state in which the sensor chip and the magnetic bodies 10 and 20 constituting the magnetic detection section 30 are separated. FIG. 6 is a schematic plan view of a sensor chip that constitutes the magnetic detection section 30. As shown in FIG. 7 is a schematic cross-sectional view taken along line BB of FIG. 6. FIG. FIG. 8 is a schematic perspective view for explaining the structure of the magnetic sensor 5 according to the fifth embodiment of the invention. FIG. 9 is a schematic perspective view for explaining the structure of the magnetic sensor 6 according to the sixth embodiment of the invention.

Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

<First Embodiment>
FIG. 1 is a schematic diagram for explaining the structure of a magnetic sensor 1 according to a first embodiment of the invention.

As shown in FIG. 1 , the magnetic sensor 1 according to the first embodiment includes magnetic bodies 10 and 20 and a magnetic detection section 30 . The magnetic bodies 10 and 20 are made of a high magnetic permeability material such as ferrite, and are substantially rod-shaped bodies with the y-direction as the longitudinal direction. The magnetic detection unit 30 is arranged between one end 11 of the magnetic body 10 and one end 21 of the magnetic body 20, thereby detecting the direction and strength of the magnetic flux φ passing between the one end 11 of the magnetic body 10 and the one end 21 of the magnetic body 20. to detect

The other end 12 of the magnetic body 10 and the other end 22 of the magnetic body 20 are bent in the x-direction so as to face each other, thereby forming a detection probe P that is close to each other. The detection probe P plays a role of collecting the magnetic flux generated from the object A to be detected. The detection target A is arranged, for example, between the other end 12 of the magnetic body 10 and the other end 22 of the magnetic body 20 or in the vicinity thereof. As a result, the magnetic flux φ in the x direction generated from the detection object A is collected by the magnetic bodies 10 and 20 and applied to the magnetic detection section 30 . That is, since the magnetic bodies 10 and 20 and the magnetic detection unit 30 form a magnetic loop through the detection probe P, the magnetic flux generated from the detection object A located near the detection probe P can be detected with high sensitivity. It becomes possible.

As described above, in the magnetic sensor 1 according to the present embodiment, since the other end 12 of the magnetic body 10 and the other end 22 of the magnetic body 20 constitute the detection probe P, the magnetic flux in a minute area can be detected with high sensitivity. becomes possible.

<Second embodiment>
FIG. 2 is a schematic diagram for explaining the structure of the magnetic sensor 2 according to the second embodiment of the invention.

As shown in FIG. 2, in the magnetic sensor 2 according to the second embodiment, a non-magnetic body 40 made of resin or the like is arranged between the other end 12 of the magnetic body 10 and the other end 22 of the magnetic body 20. is different from the magnetic sensor 1 according to the first embodiment. Since other basic configurations are the same as those of the magnetic sensor 1 according to the first embodiment, the same elements are denoted by the same reference numerals, and overlapping descriptions are omitted.

The non-magnetic body 40 is adhered to the other end 12 of the magnetic body 10 and the other end 22 of the magnetic body 20, thereby playing a role of positioning and fixing them. Using such a non-magnetic material 40 not only fixes the distance between the detection probes P in the x direction, but also makes it possible to increase the mechanical strength of the detection probes P. FIG.

<Third Embodiment>
FIG. 3 is a schematic diagram for explaining the structure of the magnetic sensor 3 according to the third embodiment of the invention.

As shown in FIG. 3, the magnetic sensor 3 according to the third embodiment has a shape in which the cross-sectional areas of the magnetic bodies 10 and 20 become smaller toward the detection probe P, in that the magnetic sensor 1 according to the first embodiment is different from Since other basic configurations are the same as those of the magnetic sensor 1 according to the first embodiment, the same elements are denoted by the same reference numerals, and overlapping descriptions are omitted.

If the magnetic bodies 10 and 20 have such a shape, the tip of the detection probe P is miniaturized, so that the tip of the detection probe P can be easily brought closer to the detection object A, and magnetic flux in a finer area can be detected. It becomes possible to

<Fourth Embodiment>
FIG. 4 is a schematic perspective view for explaining the structure of a magnetic sensor 4 according to a fourth embodiment of the invention.

As shown in FIG. 4, the magnetic sensor 4 according to the fourth embodiment has a shape in which the magnetic bodies 10 and 20 are bent into a hook shape, and a sensor chip is used as the magnetic detection section 30. It differs from the magnetic sensor 3 according to the embodiment of No. 3. Since other basic configurations are the same as those of the magnetic sensor 3 according to the third embodiment, the same elements are denoted by the same reference numerals, and overlapping descriptions are omitted.

The magnetic body 10 has a shape that is bent twice at right and obtuse angles from one end 11 to the other end 12 . The magnetic body 20 is divided into two ends 21a and 21b and has a shape in which the ends 21a and 21b are bent twice at a right angle and an obtuse angle toward the other end 22. As shown in FIG. The other end 12 of the magnetic body 10 and the other end 22 of the magnetic body 20 that constitute the detection probe P both form an xz plane and are located on the same plane. This not only makes it easier to bring the detection probe P closer to the xz plane of the detection target A, but also makes it possible to bring the detection probe P into contact with the xz plane of the detection target A.

Further, in the present embodiment, the angle θ formed by the extending direction of the magnetic body 10 on the other end 12 side and the extending direction of the magnetic body 20 on the other end 22 side is an obtuse angle. Thereby, it is possible to more efficiently collect the x-direction magnetic flux generated from the object A to be detected.

FIG. 5 is a schematic exploded perspective view showing a state in which the sensor chip and the magnetic bodies 10 and 20 constituting the magnetic detection section 30 are separated.

As shown in FIG. 5, the sensor chip that constitutes the magnetic detection unit 30 has an element forming surface 31 and a back surface 32 that constitute the yz plane, side surfaces 33 and 34 that constitute the xy plane, and a side surface 35 that constitutes the xz plane. , 36 . Magneto-sensitive elements and magnetic layers M1 to M3, which will be described later, are formed on the element forming surface 31 of the sensor chip. A portion constituting one end 11 of the magnetic body 10 is a rod-shaped body having its longitudinal direction in the x direction, and the one end 11 in the x direction is approximately the same as the element formation surface 31 in the z direction so as to cover a part of the magnetic layer M1. Centrally positioned. The magnetic body 20 has a bar-shaped region 23 whose longitudinal direction is the x direction. The end portion of the region 23 on the sensor chip side is divided into two, extending in the x direction, and further bent in the z direction so as to face each other. The portions bent in the z-direction constitute ends 21 a and 21 b of the magnetic body 20 . One ends 21a and 21b cover portions of the magnetic layers M2 and M3, respectively.

6 is a schematic plan view of a sensor chip that constitutes the magnetic detection section 30, and FIG. 7 is a schematic cross-sectional view taken along line BB in FIG.

As shown in FIGS. 6 and 7, four magneto-sensitive elements R1 to R4 are formed on the element forming surface 31 of the sensor chip. The magneto-sensitive elements R1 to R4 are not particularly limited as long as they are elements whose electric resistance changes depending on the direction of the magnetic flux, and for example, MR elements can be used. The fixed magnetization directions of the magneto-sensitive elements R1 to R4 are aligned in the same direction (for example, the plus side in the z-direction). The magneto-sensitive elements R1 to R4 are covered with an insulating layer 37, and magnetic layers M1 to M3 made of permalloy or the like are formed on the surface of the insulating layer 37. As shown in FIG. The magnetic layers M1 to M3 are covered with an insulating layer . Of the magnetic layers M1 to M3, portions positioned on one side in the y direction (upper side in FIG. 7) are defined as magnetic layers M11, M21, and M31, and the other side in the y direction (lower side in FIG. 7) ) are defined as the magnetic layers M12, M22, and M32, the magneto-sensitive element R1 is positioned between the magnetic layers M11 and M21 in plan view (viewed from the x direction), The magneto-sensitive element R2 is positioned between the magnetic layers M12 and M22, the magneto-sensitive element R3 is positioned between the magnetic layers M11 and M31, and the magneto-sensitive element R4 is positioned between the magnetic layers M12 and M12. It is positioned between the magnetic layers M32. As a result, a magnetic field passing through the magnetic gaps G1-G4 is applied to the magneto-sensitive elements R1-R4. Here, since the direction of the magnetic field applied to the magneto-sensitive elements R1 and R2 and the direction of the magnetic field applied to the magneto-sensitive elements R3 and R4 are different from each other by 180°, the magneto-sensitive elements R1 to R4 are bridge-connected. Thus, the direction and intensity of the magnetic flux applied through the magnetic body 10 can be detected.

However, in the present invention, it is not essential to arrange the magneto-sensitive elements R1 to R4 between the two magnetic layers. It is sufficient that the magneto-sensitive elements R1 to R4 are arranged on the magnetic path formed by. Further, the width of the magnetic gaps G1-G4 need not be wider than the width of the magneto-sensitive elements R1-R4, and the width of the magnetic gaps G1-G4 may be narrower than the width of the magneto-sensitive elements R1-R4.

6 and 7, the region indicated by reference numeral 11 indicates the region covered by one end 11 of the magnetic body 10, and the regions indicated by reference numerals 21a and 21b indicate the regions covered by the one ends 21a and 21b of the magnetic member 20. In FIGS. . As shown in FIGS. 6 and 7, one end 11 of the magnetic body 10 covers the magnetic layer M1, and one ends 21a and 21b of the magnetic body 20 cover the magnetic layers M2 and M3.

With such a configuration, the magnetic bodies 10 and 20 and the magnetic layers M1 to M3 form a magnetic loop through the detection probe P, and the magnetosensitive elements R1 to R4 are arranged in the magnetic gaps G1 to G4 included in the magnetic loop. Therefore, it becomes possible to detect the magnetic flux generated from the detection object A located near the detection probe P with high sensitivity.

<Fifth Embodiment>
FIG. 8 is a schematic perspective view for explaining the structure of the magnetic sensor 5 according to the fifth embodiment of the invention.

As shown in FIG. 8, the magnetic sensor 5 according to the fifth embodiment differs from the magnetic sensor 4 according to the fourth embodiment in that the magnetic bodies 10 and 20 are bent once at an acute angle. is doing. Since other basic configurations are the same as those of the magnetic sensor 4 according to the fourth embodiment, the same elements are denoted by the same reference numerals, and overlapping descriptions are omitted.

As exemplified by the magnetic sensor 5 shown in FIG. 8, if the magnetic bodies 10 and 20 are bent at an acute angle, the overall size in the y direction can be reduced.

<Sixth Embodiment>
FIG. 9 is a schematic perspective view for explaining the structure of the magnetic sensor 6 according to the sixth embodiment of the invention.

As shown in FIG. 9, in the magnetic sensor 6 according to the sixth embodiment, the magnetic body 10 has a shape in which the magnetic body 10 is bent once at right angles, and the magnetic body 20 has a shape in which the magnetic body 20 is bent twice at right angles and obtuse angles. In this respect, it differs from the magnetic sensor 4 according to the fourth embodiment. Since other basic configurations are the same as those of the magnetic sensor 4 according to the fourth embodiment, the same elements are denoted by the same reference numerals, and overlapping descriptions are omitted.

In this embodiment, the magnetic body 10 has a constant cross-sectional area in the vicinity of the other end 12 and has a simpler shape. As exemplified by the magnetic sensor 6 shown in FIG. 9, the shape of the magnetic bodies 10 and 20 is not particularly limited in the present invention.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention. Needless to say, it is included within the scope.

1 to 6 magnetic sensors 10, 20 magnetic bodies 11, 21, 21a, 21b one end 12, 22 of the magnetic body the other end 23 of the magnetic body region 30 magnetic detection portion 31 element forming surface 32 rear surface 33 to 36 side surfaces 37, 38 insulating layer 40 Non-magnetic material A Detection object G1-G4 Magnetic gaps M1-M3, M11, M21, M31, M12, M22, M32 Magnetic layer P Detection probes R1-R4 Magneto-sensitive element φ Magnetic flux

Claims (4)

first and second magnetic bodies;
a magnetic detection unit that detects magnetic flux passing between one end of the first magnetic body and one end of the second magnetic body,
The magnetic sensor, wherein the other end of the first magnetic body and the other end of the second magnetic body are close to each other. 2. The magnetic sensor according to claim 1, wherein said other end of said first magnetic body and said other end of said second magnetic body are positioned on the same plane. 3. The magnetic sensor according to claim 1, wherein each of said first and second magnetic bodies has a shape with a cross-sectional area decreasing toward said other end. 4. An angle formed by an extending direction of said first magnetic body on said other end side and an extending direction of said second magnetic body on said other end side is an obtuse angle. The magnetic sensor according to any one of 1.

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