JP2636533B2 - Magnetic sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magnetic sensor,
More specifically, the present invention relates to a technique for improving the sensitivity.

[0002]

2. Description of the Related Art Conventionally, when constructing a magnetic sensor to be incorporated in a potentiometer or the like, a magnetoelectric conversion element such as a magnetoresistive element or a Hall element has been used. In these magnetic sensors, a magnetoresistive element 1 as a magnetoelectric conversion element is disposed on one plane of a magnet 2 as shown in FIG. A configuration in which a magnetic field is applied to the element 1 is generally adopted.

In order to improve the sensitivity of the magnetic sensor, a magnet having a stronger magnetic field is used as the magnet 2 shown in FIG. 2 or, as shown in FIG. A flat magnetic member 3 made of a high-permeability magnetic material such as ferrite is interposed between the magnet 2 and the magnet 2.

[0004]

However, each of the conventional magnetic sensors has the following disadvantages. First, in the magnetic sensor illustrated in FIG. 2, since the equipotential surface (indicated by a virtual line) of the magnet 2 has a bulged shape at the center, the magnetic efficiency is reduced. Therefore, in order to avoid such inconvenience, the planar size of the magnet 2 is increased as shown in FIG. As a result, the end of the equipotential surface (indicated by a phantom line) is larger than the center, so that a stable high level of sensitivity cannot be obtained.

In the magnetic sensor shown in FIG. 3, the magnetic flux from the magnet 2 is drawn toward the magnetoresistive element 1 by the edge of the magnetic member 3, that is, inward. The magnetic flux concentrates on the portion, and the magnetic flux density increases. However, at this time, at the same time, even the magnetic flux at the center of the magnetoresistive element 1 is affected by the magnetic member 3 interposed over the entire surface, and the direction of the magnetic flux may not be vertical but inclined. As a result, the magnetic efficiency is reduced as a result. Therefore, even with the magnetic sensor having the configuration shown in FIG. 3, only the equipotential surface having the shape shown by the imaginary line in FIG. 3 can be obtained, and a high level of sensitivity cannot be stably obtained.

The present invention has been made in view of such inconvenience, and can improve sensitivity by improving magnetic efficiency, and can easily obtain a stable and high level of sensitivity. It aims to provide a magnetic sensor.

[0007]

In order to achieve the above object, a magnetic sensor according to the present invention has a magneto-electric conversion element, a magnetic member surrounding the side surface thereof, and these disposed on the same plane. And a magnet.

[0008]

According to the above construction, since only the side surface of the magneto-electric conversion element disposed on the magnet is surrounded by the magnetic member, the edge of the magneto-electric conversion element is affected by the magnetic member and has a magnetic flux. Are concentrated, and the direction of the magnetic flux at this edge is vertical. At this time, since no magnetic member is interposed between the magnetoelectric conversion element and the magnet, the direction of the magnetic flux in the central portion of the magnetoelectric conversion element is affected by the magnetic member and is perpendicular. Does not tilt from

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory diagram showing a simplified configuration of a main part of a magnetic sensor according to the present embodiment. Since the basic configuration of this magnetic sensor is not different from the conventional example,
1. In FIG. 1, the same or equivalent parts as in FIG.
Parts are given the same reference numerals.

The magnetic sensor according to the present embodiment includes a magnetoresistive element 1 which is a magnetoelectric conversion element, a magnet 2 disposed on one plane, and the same as that on which the magnetoresistive element 1 is disposed. The magnetic member 5 is provided on a plane and surrounds only the side surface of the magnetoresistive element 1. In addition, the magnetic member 5 in FIG. 1 is made of a high-permeability magnetic material such as ferrite, and is formed as an annular shape into which the magnetoresistive element 1 can be fitted. However, the present invention is not limited to this. For example, even when an annular magnet having the same polarity as the magnet 2 is provided, or
It may be formed by cutting one plane of the magnet 2.

That is, in this magnetic sensor,
Since only the periphery of the side surface of the magnetoresistive element 1 is surrounded by the magnetic member 5, the magnetic flux from the magnet 2 is concentrated on the edge of the magnetoresistive element 1, and the magnetic flux density at the edge is higher than that at the center. Will increase. And then,
Since the magnetic member 3 as in the conventional example shown in FIG. 3 is not interposed between the magnetoresistive element 1 and the magnet 2, and both of them are in direct contact, the magnetoresistive element The direction of the magnetic flux at the central portion of 1 does not incline from the vertical, and at the same time, the direction of the magnetic flux at the edges remains vertical.

[0013]

As described above, according to the magnetic sensor of the present invention, the magnetic flux concentrates on the edge of the magneto-electric conversion element disposed on the magnet, and at the same time, the center of the magneto-electric conversion element and Since the direction of the magnetic flux at the edge is vertical, the magnetic efficiency is improved. Therefore, the sensitivity of the magnetic sensor can be improved through the improvement of the magnetic efficiency, and an effect that a stable and high level of sensitivity can be easily obtained is obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a simplified configuration of a main part of a magnetic sensor according to an embodiment.

FIG. 2 is an explanatory diagram schematically showing an example of a magnetic sensor according to a conventional example.

FIG. 3 is an explanatory view showing another example of the magnetic sensor according to the conventional example.

FIG. 4 is an explanatory diagram showing a modification of the magnetic sensor shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic resistance element (magnetoelectric conversion element) 2 Magnet 3 Magnetic member

Claims (1)

(57) [Claims] 1. A magnetic device comprising: a magnetoelectric conversion element (1); a magnetic member (5) surrounding the periphery of a side surface thereof; and a magnet (2) provided on the same plane. sensor.