JPH0518752A - Earth magnetism detecting device - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the detection sensitivity by effectively guiding the geomagnetism from the magnetic focusing end of the magnetic lens to the magnetic sensitive element. A magnetic conducting material 3 is provided between a magnetic flux converging end 30a and a substrate 38 on which a magnetoresistive pattern 36 which is a magnetic sensing element is formed.
4 are interposed. This magnetic material has a magnetic flux converging end 3
The cross section is gradually reduced from the 0a side to the substrate 38 side. Therefore, the magnetic flux emitted from the magnetic flux converging end 30a is further converged without spreading and effectively reaches the magnetoresistive element pattern 36, and the detection sensitivity is enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a geomagnetism detecting device in which a magnetic lens is joined to a geomagnetic sensor having a magnetic sensitive element covered with a protective layer.

[0002]

2. Description of the Related Art As is well known, geomagnetism has a substantially constant direction and magnitude on the surface of the earth, and has been conventionally used as a reference for azimuth.

In recent years, a navigation system for obtaining the traveling direction of an automobile by utilizing such geomagnetism has been developed, and in order to improve the accuracy of such a system, a geomagnetic detection device having a higher sensitivity and a smaller size has been developed. Is requested.

In FIG. 4, the present applicant has previously filed Japanese Patent Application No. 2-46.
The schematic configuration of the geomagnetic detection device proposed in No. 957 is shown. This geomagnetic detector is composed of two detectors 10 and 12 whose main sensitivity directions are orthogonal to each other. Each detection unit is composed of magnetic lenses 14 and 16 and geomagnetic sensors 18 and 20, and detection circuits and the like are omitted in the drawing.

Here, the magnetic lenses 14 and 16 are
One end is widened and the other end is tapered. The geomagnetic sensors 18 and 20 described above are joined and arranged on the tapered end surface. Therefore, according to such a geomagnetism detection device, the geomagnetism is obtained as two azimuth components orthogonal to each other, and the azimuth of the geomagnetism can be discriminated from the result.

FIG. 5 shows a specific structure of the geomagnetic sensor shown in FIG. Since the geomagnetic sensors 18 and 20 have the same structure, the geomagnetic sensor 18 will be described below.

In FIG. 5, a magnetoresistive element pattern 24 is formed on the upper surface of the substrate 22 by an exposure technique, while a bias magnet 26 for generating a bias magnetic field is bonded to the lower surface of the substrate 22. Magnetoresistive element pattern 2
The output of 4 is the four leads 30 via the four electrodes 28.
Taken from.

In such a geomagnetic sensor, like the LSI chip, for example, a resin mold 100 is applied as a protective layer in order to protect the magnetic sensing element inside and to securely hold the lead 30. Incidentally, this protective layer 100 is formed with a thickness of 0.5 to 1.0 mm.
In addition to the above, a Hall element, a magnetic diode, or the like is used as the magnetic sensing element for detecting the earth magnetism.

[0009]

SUMMARY OF THE INVENTION The protective layer 10 described above.
0 is indispensable especially for protecting the magnetoresistive element pattern 24. That is, the protective layer 100 is necessary for isolating the magnetoresistive pattern 24 from moisture and oxygen in the atmosphere or for physical protection.

However, the presence of the protective layer 100 causes divergence and leakage of the geomagnetism that should have converged in the magnetic passage path from the magnetic converging end of the magnetic lens joined to the geomagnetic sensor to the magnetoresistive element pattern 24. As a result, there is a problem that the sensitivity of geomagnetic detection is reduced. FIG. 3 shows the relationship between the distance from the magnetic focusing end of the magnetic lens and the strength of the magnetic field for reference. As can be seen, it is understood that if the distance from the converging end becomes unnecessarily long, the magnetic flux that should have been sufficiently converged will spread, and the magnetic field will be weakened as a result.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to effectively guide the geomagnetism from the magnetic lens to the magnetic sensitive element without leakage and improve the detection sensitivity of the geomagnetic detection device. And

[0012]

In order to achieve the above object, the present invention has a geomagnetic sensor in which a magnetic sensitive element for detecting geomagnetism is wrapped with a protective layer, and a magnetic focusing end is joined to the geomagnetic sensor. In a geomagnetism detecting device having at least one magnetic lens, a magnetic material having a cross section gradually decreasing from a magnetic converging end side to a magnetic sensitive element side in a geomagnetism passing path from the magnetic converging end to the magnetic sensitive element. Is placed.

[0013]

According to the above construction, since the magnetic conducting material is arranged between the magnetic flux converging end and the magnetic sensitive element, the magnetic flux sufficiently converged by the magnetic lens is passed from the magnetic flux concentrating end to the magnetic conducting material. The magnetic field can be effectively reached without spreading through the magnetic field. That is, it is possible to improve the detection sensitivity by further converging the magnetic flux spread in the area of the protective layer in the past.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

The geomagnetism detecting apparatus of this embodiment is composed of two detecting sections whose main sensitivity directions are orthogonal to each other, like the conventional example shown in FIG. 4, and each detecting section includes a magnetic lens and a geomagnetic sensor. It is composed of.

FIG. 1 shows an enlarged view of the main part of the geomagnetism detecting device of this embodiment. A geomagnetic sensor 32 is disposed on the magnetic converging end 30a of the magnetic lens 30 so as to be joined thereto.
This geomagnetic sensor 32 has basically the same configuration as the geomagnetic sensor shown in FIG.
Is arranged.

That is, the geomagnetic sensor 32 has a substrate 38 having a magnetoresistive element pattern 36 formed on the upper surface thereof, a bias magnet (not shown) for generating a bias magnetic field bonded to the lower surface of the substrate, and these substrates. 38 and a protective layer 40 formed by resin-molding a bias magnet. Therefore, the substrate 38 and the bias magnet constitute a magnetic sensing element.

In the present embodiment, the above-mentioned magnetic conductor 34 is arranged between the magnetic flux converging end 30a and the one side surface 38a of the substrate 38. In this example,
The surface on one side of the magnetic conductor 34 is joined to the magnetic flux converging end 30a, and the surface on the other side is joined to the side surface 38a of the substrate 38.

Here, as shown in FIG. 1, the magnetic conducting material 34 is formed such that its cross section (magnetic flux passing cross section orthogonal to the magnetic flux) gradually becomes smaller from the magnetic flux converging end 30a. Therefore, the magnetic flux emitted from the magnetic flux converging end 30a is
The magnetic conducting material 34 further converges and reaches the magnetoresistive element pattern 36.

As described above, since the magnetic conductor 34 is arranged in the magnetic passage in the protective layer 40, the magnetic flux spreading and leakage in the area of the protective layer 40, which has conventionally occurred, can be avoided, and the magnetic detection sensitivity can be avoided. Can be increased.

As with the magnetic lens 30, it is preferable to use a soft ferromagnetic material such as permalloy as the magnetic conductor 34. By the way, in this embodiment, it is confirmed that the magnetic flux convergence rate is improved by about 30 to 50% in comparison with the conventional example.

The magnetic conducting material 34 is arranged at the time of manufacture by embedding the magnetic conducting material 34 at the time of resin molding as in the case of fixing the leads 42. According to such a manufacturing process, since it is only necessary to embed the magnetic conductive material 34, no special process is required and a simple manufacturing can be realized. Of course, since the magnetoresistive element pattern 36 to be particularly protected is completely protected by the protective layer 40, the durability is almost the same as that of the conventional example.

Next, FIG. 2 shows a modification of the magnetic conducting material. The magnetic conductor 44 shown in FIG. 2 is characterized in that the surface facing the substrate is cut in an arc shape as shown. That is, since the magnetic flux generally has a property of coming out from the surface of the magnetic body in the vertical direction, it is possible to further increase the convergence rate of the magnetic flux by forming the curved surface in an arc shape. Note that the resin is poured into the cut-out arc-shaped region during resin molding,
That region becomes a part of the protective layer 40. However, since the magnetic conductor 44 and the substrate 38 are sufficiently close to each other, the sensitivity is not lowered in combination with the improvement of the convergence rate described above, and on the contrary, the sensitivity can be slightly improved. ..

As described above, according to the geomagnetism detecting apparatus of this embodiment, the converged magnetic flux can be effectively guided to the magnetoresistive element pattern without increasing the shape of the apparatus, so that the detection sensitivity is improved. Can be planned. Therefore, it is possible to configure a geomagnetism detection device that is resistant to disturbance and the like, and it is possible to provide a geomagnetism detection device suitable for a navigation system or the like.

[0025]

As described above, according to the geomagnetism detecting device of the present invention, since the magnetic conducting material is arranged in the magnetic passage path from the magnetic flux converging end to the magnetic sensitive element, the converged magnetic flux is effective as it is. Further, it is possible to improve the detection sensitivity by introducing the magnetic sensitive element. Therefore, the geomagnetic detection sensitivity can be increased.

[Brief description of drawings]

FIG. 1 is an enlarged view of a main part of a geomagnetism detection device according to the present invention.

FIG. 2 is a plan view showing a modified example of a magnetic conductor.

FIG. 3 is a characteristic diagram showing the relationship between the distance from the magnetic flux converging end and the strength of the magnetic field.

FIG. 4 is a plan view showing the overall configuration of a conventional geomagnetism detection device.

FIG. 5 is a perspective view showing the structure of a conventional geomagnetic sensor.

[Explanation of symbols]

 30 Magnetic Lens 32 Geomagnetic Sensor 34 Magnetic Material 36 Magnetoresistive Element Pattern (Magnetic Sensing Element) 38 Substrate (Magnetic Sensing Element) 40 Protective Layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenji Nishikawa, 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Corporation (72) Inventor: Toshio Hashimoto, 1 Toyota Town, Aichi Prefecture, Toyota Motor Corporation ( 72) Inventor Kazuhide Ota 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. (72) Inventor, Motoo Katayama 7 Shimoogoda, Asada, Nisshin Town, Aichi District, Aichi Prefecture Hagiwara Electric Co., Ltd. Nagoya Plant (72 ) Inventor Moriyasu Fujita 7 Shimokofukada, Asada, Nisshin-cho, Aichi-gun, Aichi Prefecture Hagiwara Electric Co., Ltd. Nagoya factory (72) Inventor Masahisa Ito 2923, Hamakita city, Shizuoka prefecture Japan Automation Co., Ltd.

Claims (1)

Claim: What is claimed is: 1. A geomagnetism comprising: a geomagnetic sensor comprising a magnetic sensitive element for detecting geomagnetism wrapped in a protective layer; and at least one magnetic lens having a magnetic flux converging end joined to the geomagnetic sensor. In the detection device, a geomagnetic material having a cross section that gradually decreases in cross section from the magnetic converging end side to the magnetic sensitive element side is disposed in the geomagnetic passing path from the magnetic converging end to the magnetic sensitive element. Detection device.