JPH04293281A - Magnetic sensor - Google Patents

Abstract

PURPOSE:To contrive the improvement of the magnetic efficiency of a magnetic sensor and the improvement of the sensitivity of the sensor and to obtain a stable high-level sensitivity. CONSTITUTION:A magnetic sensor is provided with a magnetoelectric conversion element 1, a magnetic member 5 encircling the peripheries of the side surfaces of the element 1 and a magnet 2, on which the element 1 and the member 5 are arranged on the same plane.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a magnetic sensor,
Specifically, the present invention relates to a technique for improving the sensitivity.

0002

2. Description of the Related Art Conventionally, magnetoelectric conversion elements such as magnetoresistive elements and Hall elements have been used to construct magnetic sensors that are incorporated into potentiometers and the like. In these magnetic sensors, as shown in FIG. 2 in a simplified manner, a magnetoresistive element 1, which is a magnetoelectric transducer, is disposed on one plane of a magnet 2, and the magnet 2 generates a magnetic resistance. 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, it is necessary to use a magnet with a stronger magnetic field as the magnet 2 shown in FIG. 2, or alternatively, 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

[Problems to be Solved by the Invention] Incidentally, each of the magnetic sensors having the conventional structure described above has the following disadvantages. First, in the magnetic sensor illustrated in FIG. 2, the equipotential plane (indicated by the imaginary line) of the magnet 2 has a swollen shape at the center, resulting in a decrease in magnetic efficiency. Therefore, in order to avoid such inconvenience, the planar size of the magnet 2 is increased as shown in FIG. Equimagnetic surface (
As a result, the end portions (indicated by imaginary lines) bulge out more than the center portion, making it impossible to obtain a stable high level of sensitivity.

Furthermore, in the magnetic sensor shown in FIG. 3, the magnetic flux from the magnet 2 is drawn toward the magnetoresistive element 1, that is, inwardly, by the edge of the magnetic member 3. The magnetic flux will concentrate in the area, and the magnetic flux density will increase. However, at this time, the magnetic flux at the center of the magnetoresistive element 1 is also affected by the interposed magnetic member 3 over the entire surface, and the direction of the magnetic flux may not be perpendicular but tilted. This results in a decrease in magnetic efficiency. Therefore, even in the magnetic sensor having the configuration shown in FIG. 3, only an equipotential surface having a shape as shown by the virtual line in FIG. 3 can be obtained, and a high level of sensitivity cannot be stably obtained.

The present invention has been devised in view of these inconveniences, and provides a structure that can improve sensitivity through improved magnetic efficiency and easily obtain a stable high level of sensitivity. The purpose is to provide a magnetic sensor.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the magnetic sensor according to the present invention includes a magnetoelectric conversion element, a magnetic member surrounding the side surface thereof, and a magnetic member disposed on the same plane. The invention is characterized in that it is equipped with a magnet.

[0008]

[Operation] According to the above structure, only the side periphery of the magnetoelectric transducer disposed on the magnet is surrounded by the magnetic member, so that the edge of the magnetoelectric transducer is affected by the magnetic member and receives magnetic flux. will be concentrated, and the direction of magnetic flux at this edge will be perpendicular. At this time, since no magnetic member is interposed between the magnetoelectric transducer and the magnet, the direction of the magnetic flux at the center of the magnetoelectric transducer is influenced by the magnetic member and becomes perpendicular. Leaning from the top will not happen.

[0009]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings.

FIG. 1 is an explanatory diagram showing a simplified configuration of the main parts of a magnetic sensor according to this embodiment. The basic configuration of this magnetic sensor is the same as the conventional example, so
Components in FIG. 1 that are the same as or equivalent to those in FIG. 2,
Parts are given the same reference numerals.

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

That is, in this magnetic sensor,
Since only the sides of the magnetoresistive element 1 are surrounded by the magnetic member 5, the magnetic flux from the magnet 2 is concentrated at the edge of the magnetoresistive element 1, and the magnetic flux density at the edge is higher than that at the center. It will increase. And at this time,
Unlike the conventional example shown in FIG. 3, the magnetic member 3 is not interposed between the magnetoresistive element 1 and the magnet 2, and the two are in direct contact with each other. The direction of the magnetic flux in the central part of 1 does not tilt from the vertical, and at the same time the direction of the magnetic flux in the edge parts also remains perpendicular.

[0013]

As explained above, according to the magnetic sensor according to the present invention, magnetic flux is concentrated at the edge of the magnetoelectric transducer arranged on the magnet, and at the same time, the magnetic flux is concentrated at the edge of the magnetoelectric transducer disposed on the magnet. Since the direction of magnetic flux at the edge is perpendicular, magnetic efficiency is improved. Therefore, the sensitivity of the magnetic sensor can be improved by improving the magnetic efficiency, and a stable high level of sensitivity can be easily obtained.

[Brief explanation of the drawing]

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

FIG. 2 is an explanatory diagram showing a simplified example of a conventional magnetic sensor.

FIG. 3 is an explanatory diagram showing another example of a conventional magnetic sensor.

FIG. 4 is an explanatory diagram showing a modification of the magnetic sensor shown in FIG. 2;

[Explanation of symbols]

1 Magnetoresistive element (magnetoelectric conversion element) 2 Magnet 3 Magnetic member

Claims (1)

[Claims] 1. A magnetic device comprising a magnetoelectric conversion element (1), a magnetic member (5) surrounding the side surface thereof, and a magnet (2) in which these elements are arranged on the same plane. sensor.