JP2003008099A - Magnetic sensing element - Google Patents

Abstract

(57) [Problem] To provide a magnetic detection element having a simple configuration and high detection sensitivity. SOLUTION: A first soft magnetic film is formed on an insulating substrate,
A second soft magnetic film is formed on the first soft magnetic film via an insulating film. A current path for flowing a high-frequency current is provided in a part of the second soft magnetic film. A third magnetic film is further formed on the second magnetic film via an insulating film. When a magnetic pole made of the first to third magnetic films is placed in an external magnetic field and a high-frequency current flows through the current path, the impedance of the current path changes due to the external magnetic field. From the impedance change, the strength and direction of the magnetic field are detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic detecting element for detecting weak magnetism and magnetic field.

[0002]

2. Description of the Related Art As a magnetic detection element (magnetic sensor) for detecting a weak magnetic field or a magnetic field, a magnetoresistive effect type magnetic sensor (hereinafter referred to as MR sensor) has been conventionally known.
The MR sensor detects a magnetic field by utilizing the magnetoresistive effect in which the resistance value of the MR sensor changes according to the strength of the magnetic field.
The change in resistance due to the magnetoresistive effect is symmetrical with respect to the reversal magnetic field. Therefore, in order to detect the polarity (N or S) of the magnetic field by the MR sensor, a bias magnetic field is applied to the MR sensor so that the change in resistance due to the magnetic field is asymmetric with respect to the polarity of the magnetic field. To give a bias field
There are a method in which a conductor is provided below or above the magnetic pole of the MR sensor and a bias current is passed through the conductor, and a method in which a permanent magnet film is arranged at both ends of the magnetic pole. The MR sensor detects a magnetic field by the change in the direct current resistance of the conductor due to the external magnetic field, and the change in the direct current resistance is greatly affected by the magnetic material. The magnetic field detection sensitivity is about 0.1% to 3% / Oe, which is not very high. As a magnetic detection element having a higher detection sensitivity than that of an MR sensor, there is one that utilizes a magnetic impedance effect. This type of magnetic sensor detects a magnetic field based on a change in impedance of a conductor in a magnetic circuit due to a change in magnetic permeability of a soft magnetic material. The sensitivity of a typical magnetic sensor of this type is 6% / Oe or more.

An example of such a magnetic sensor utilizing the magnetic impedance effect is disclosed in Japanese Patent Application Laid-Open No. 7-63832 (hereinafter referred to as a conventional example). FIG. 16 is a partial sectional view of the conventional magnetic sensor. In the configuration of FIG. 16A, the two magnetic bodies 3A and 3B are bonded to each other to form the magnetic pole 3, and the conductor 2 is sandwiched between the magnetic bodies 3A and 3B.
The magnetic body 3B has a stepped portion 3D. In the configuration of FIG. 16B, the insulating material 5 is provided on the flat plate-shaped magnetic body 4A, and the conductor 2 is arranged so as to penetrate the central portion of the insulating material 5. The magnetic body 4B is formed so as to surround the insulating material 5,
The upper and lower ends of the magnetic body 4B are bonded to the magnetic body 4A to form the magnetic pole 4. High-frequency current is passed through the conductor 2,
The magnetic field is detected based on the change in the impedance of the conductor 2 due to the external magnetic field. The bias magnetic field is applied by passing a DC bias current through the conductor 2.

[0004]

In the structure of FIG. 16 (a), when a direct current is applied to the conductor 2, direct current bias magnetic fields indicated by arrows 6 and 7 are applied to the magnetic bodies 3A and 3B. Occur. When there is an external magnetic field indicated by the arrow 1, the DC bias magnetic field 6 of the magnetic body 3A is in the opposite direction to the external magnetic field 1 and is weakened. Therefore, the DC bias magnetic field cannot be effectively applied to the magnetic pole 3. Also, FIG.
In the configuration shown in FIG. 6 (b), the magnetic body 4B on the right side is formed in a mountain shape in order to get over the insulating material 5. Therefore, stepped portions 4D are formed on both sides of the mountain-shaped top. As a result of various experiments by the inventor, the magnetic pole 3 having the stepped portion 3D,
The magnetic pole 4 having the stepped portion 4D has a low magnetic permeability, and the impedance of the conductor when external magnetization is applied is also low. Therefore, it was found that the sensitivity of the magnetic sensor was low. It is an object of the present invention to obtain a sensor using the magneto-impedance effect, which is more sensitive than the above-mentioned prior art.

[0005]

The magnetic sensing element of the present invention comprises a first soft magnetic film formed on an electrically insulating member, and an electrically insulating film on the first soft magnetic film. A second soft magnetic film having a pair of electrical connection portions formed thereon, a third soft magnetic film formed on the second soft magnetic film via an electrically insulating film, and It has an electrode for connecting the first pair of electrical connection lines to an external high frequency power supply. According to the present invention, the device has the following actions and effects.
A magnetic pole is formed by stacking three soft magnetic films via an electrically insulating film, and a high-frequency current is passed through a current path in a part of the soft magnetic film in the center of the magnetic pole. The high frequency current causes a magnetic field surrounding the current path in the soft magnetic film around the current path. When the magnetic pole is placed in the external magnetic field in this state, the magnetic flux due to the external magnetic field changes the magnetic field around the current path and changes the impedance of the current path. Since the impedance is inversely proportional to the strength of the magnetic field, the magnitude of the external magnetic field can be detected by detecting this impedance change.

The impedance change becomes maximum when the direction of the external magnetic field is perpendicular to the direction of the current flowing through the current path. Therefore, the direction of the external magnetic field can be detected by obtaining the minimum impedance value. Since the magnetic film of the magnetic pole has no large unevenness, the magnetic permeability is kept at the highest level and the impedance change is also at the highest level. Therefore, a magnetic detection element with high detection sensitivity can be realized.

According to another aspect of the present invention, there is provided a magnetic detection element comprising a first soft magnetic film formed on an electrically insulating member,
A conductor formed on a part of the first soft magnetic film via an electrically insulating film, and a part of the first soft magnetic film other than the part on which the conductor is formed electrically insulated. Second soft magnetic film formed via a conductive film, and a third soft magnetic film formed on the conductor and the second soft magnetic film via an electrically insulating film.
And a soft magnetic film, and electrodes which are connected to both ends of the conductor through connecting portions and which connect the conductor to an external high frequency power source. According to this element, in addition to the above-described effects, since the current path is a conductor, the direct current resistance is low and the high frequency current flowing through the current path can be increased. This further improves the sensitivity of magnetic detection. Furthermore, since the magnetic flux density inside the magnetic pole generated by the external magnetic field becomes higher around the conductor,
A magnetic field that is substantially stronger than the actual magnetic field is given, and the detection sensitivity is further improved.

According to another aspect of the present invention, there is provided a magnetic detecting element comprising: a plurality of first soft magnetic films formed in parallel on an electrically insulating member; At least two conductors formed at a predetermined distance via an electrically insulative film, and electrically connected to other parts except the part where the conductor is formed on each of the first soft magnetic films. A second soft magnetic film formed via an insulating film, a third soft magnetic film formed on the conductor and the second soft magnetic film via an electrically insulating film, the first soft magnetic film A connecting part formed on each of the soft magnetic films for connecting the at least two conductors in series, and electrodes connected to both terminals of the connecting part for connection to a high frequency power source. According to this element, since the plurality of conductors are connected in series, the change in impedance of the conductor increases in proportion to the number of conductors connected in series. As a result, the detection sensitivity of the external magnetic field can be significantly increased.

In the method for manufacturing a magnetic sensing element of the present invention, a step of forming a rectangular first soft magnetic film on an insulating substrate, and a step of forming an electric insulating film on the first soft magnetic film. Forming a soft magnetic film on the entire surface of the insulating substrate including the upper surface of the electrical insulating film; etching the soft magnetic film to form a rectangular second soft magnetic film and the second soft magnetic film;
Removing the other part leaving a pair of connection parts for connecting between the soft magnetic film and the electrode formed in a later step, and forming an electrical insulating film on the second soft magnetic film. Forming, forming a third soft magnetic film on the electrical insulating film, and connecting to the connecting portion of the second soft magnetic film at a predetermined distance on the insulating substrate. So as to form a pair of electrodes.

According to another aspect of the present invention, there is provided a method of manufacturing a magnetic sensing element, which comprises a step of forming a rectangular first soft magnetic film on an insulating substrate, and an electric insulating film on the first soft magnetic film. A step of forming a conductor film on the electrical insulating film, leaving the conductor film only in the central portion on the electrical insulating film, and from the remaining central conductor A conductor and a pair of connecting portions that extend substantially perpendicular to the rectangular first soft magnetic film and are removed by etching to leave a pair of connecting portions for connecting to electrodes formed in a later step. A step of forming an electric insulating film on the conductor, a step of forming a soft magnetic film on the electric insulating film, a step of etching away a soft magnetic film near the conductor, the conductor And no electrical loss on the soft magnetic film A step of forming a film, a step of forming a third soft magnetic film on the insulating film, and a step of electrically connecting to the pair of connection portions at a predetermined distance on the insulating substrate. Forming a pair of electrodes.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the magnetic sensing element of the present invention will be described below with reference to FIGS.

<< First Embodiment >> FIG. 1 is a perspective view of a magnetic detection element according to a first embodiment of the present invention. 2 is the II-II of FIG.
It is sectional drawing in the cross section shown by a line. As shown in FIG. 1, a strip-shaped conductor, preferably a copper-based sputtered film electrode 11, 12 parallel to each other at a predetermined distance is provided on an insulating substrate 10 of a non-magnetic material preferably made of TiNiMgOx as a ceramic. ing. As the ceramic material, TiCaOx or the like may be used in addition to the above TiNiMgOx. As the electrodes 11 and 12, an aluminum (Al) -based or gold (Au) -based sputtered film, a plated film, a deposited film, or the like can be used in addition to the copper-based sputtered film. Insulating substrate 10
Has a thickness of about 0.5 mm, and the electrodes 11, 12 have a thickness of about 2.0 μm. Between the electrode 11 and the electrode 12, a magnetic pole 20 which is a main part of the magnetic detection element is provided. The magnetic pole 20 includes the first magnetic film 13 and the second magnetic film 14.
And the third magnetic film 15 has a laminated structure, and each magnetic film 13
A non-magnetic insulating film 21 of a SiO ₂ film having a thickness of 0.1 μm is provided between Nos. The magnetic films 13 to 15 are FeT
It is a film of soft magnetic material such as aN, and its thickness is about 0.5μ.
m. The magnetic film 14 has connecting portions 16 and 17 orthogonal to the longitudinal direction thereof. The connecting portions 16 and 17 are the magnetic film 1.
It is provided on the insulating substrate 10 by using the same material as that of No. 4. The end faces 18 of the portions of the connecting portions 16 and 17 formed obliquely with respect to the substrate surface 10 are electrically connected to the magnetic film 14. Also, the insulating substrate 1 of the connecting portions 16 and 17
The respective end faces 19 of the portion in contact with 0 have electrodes 11, 12
Are each electrically connected to. When a high-frequency voltage is applied between the electrodes 11 and 12 by the high-frequency power supply 100, a high-frequency current flows in a current path extending to the electrode 11, the connecting portion 16, the magnetic film 14, the connecting portion 17, and the electrode 12. This high-frequency current causes a high-frequency magnetic field indicated by an arrow around the current path 16A in the magnetic film 14 connected to the connecting portion 16 of FIG. 1 in the cross-sectional view of FIG.

In the magnetic sensing element shown in FIG. 1, the electrodes 11,
Although a shape in which one magnetic pole 20 is provided between 12 is shown, the number of the magnetic pole 20 is not limited to one. In another example of this embodiment shown in the plan view of FIG. 3, four magnetic poles 20A,
20B, 20C and 20D are provided. The number of the magnetic poles 20 is not limited to four and can be any number. The four magnetic poles 20A to 20D are electrically connected in series by the connecting portion 25. Both ends of the series connection body are connected to the electrodes 11 and 12, respectively. In order to apply a magnetic bias to the magnetic detection element shown in FIG. 1 of the present embodiment, a conductor (not shown) for generating a DC bias magnetic field may be arranged near the magnetic pole 20.

Electrodes 11 and 1 of the magnetic detector of this embodiment
When a high-frequency current of, for example, a frequency of 10 MHZ is passed between the two and placed in an external magnetic field such as geomagnetism indicated by the arrow 30, the impedance of the current path 16A in the magnetic film 14 changes. The strength of the magnetic field can be detected by detecting this impedance change. As a method of detecting the change in impedance, the high frequency power supply 100 and the electrode 11 or 1
The simplest method is to connect a resistor in series with 2 and to detect the amplitude change of the high frequency voltage between both terminals of the resistor. As another method, the amplitude change of the high frequency voltage across the current path 16A may be detected. The change of impedance is the magnetic pole 20
It becomes maximum when the longitudinal direction of is coincident with the direction of the external magnetic field. Thereby, the direction of the external magnetic field can be detected.

In the magnetic sensing element of this embodiment, the surface of the magnetic pole 20 (the upper surface of 20 in FIG. 1) is flat, and there is no step like the stepped portion 4D of FIG. 16 (b) of the prior art. Therefore, the magnetic characteristics of the magnetic film 15 are not deteriorated, and high magnetic permeability can be obtained. Therefore, the change in the impedance of the current path 16A with respect to the change in the external magnetic field 30 is large, and a magnetic detection element having high detection sensitivity can be realized.
Since the cross-sectional shape of the magnetic film 14 connected by the connecting portions 16 and 17 and the cross-sectional shape of the upper and lower magnetic films 13 and 15 that sandwich the magnetic film 14 are substantially equal to each other, the magnetic flux generated by the external magnetic field 30 causes the magnetic films 13 and 14 to cross. , 15 evenly. Therefore, it is possible to obtain the magnetic detection element having a good linearity in the change of the impedance with respect to the strength of the external magnetic field.

In the example of FIG. 3, since the connecting portions 25 of the four magnetic poles 20A to 20D are connected in series with each other, the amount of change in impedance due to the external magnetic field is four times that in FIG. Therefore, the detection sensitivity of the magnetic detection element is also quadrupled, and a highly sensitive magnetic detection element can be obtained. The detection sensitivity increases as the number of the magnetic poles 20A to 20D increases, but the impedance also increases, so that it is necessary to increase the voltage of the high frequency power source for supplying the high frequency current. The number of magnetic poles may be set appropriately according to the purpose of use.

<Second Embodiment> A magnetic detection element according to a second embodiment of the present invention will be described with reference to FIGS. 4 and 5. FIG. 4 is an oblique projection view of the magnetic detection element of the second embodiment.
FIG. 5 is a sectional view taken along line VV of FIG. 4. In the following examples, the same parts as in Example 1 are made of the same material. In FIG. 4, a non-magnetic insulating substrate 1 such as ceramics is used.
Electrodes 1 made of strip-shaped conductors parallel to each other at a predetermined distance above 0
1, 12 are provided. The insulating substrate 10 has a thickness of about 0.5 mm, and the electrodes 11 and 12 have a thickness of about 2.0 μ.
m. A magnetic pole 40 is provided between the electrodes 11 and 12. The magnetic pole 40 has strip-shaped magnetic films 33, 34, and 35 that are sequentially formed on the insulating substrate 10. As shown in the cross-sectional view of FIG. 5, the magnetic film 34 has a central portion divided by a conductor 36 such as copper. Conductor 36 and magnetic film 3
3, 34 and 35 are electrically insulated from each other by insulating films 21 and 21A. On both side surfaces of the magnetic film 34 shown in FIG. 4, the conductors 36 are connected to the respective flat portions 36B formed on the surface of the insulating substrate 10 via the respective inclined surface portions 36A. The respective end faces 36C of both flat portions 36B are connected to the electrodes 11 and 12, respectively. The magnetic films 33 and 34 and the magnetic films 34 and 35 are electrically insulated by the insulating films 21 and 21A, respectively. The magnetic films 33 and 35 are, for example, FeTaN films, and both have a thickness of about 0.5 μm. Magnetic body 34
Is a film of FeTaN and has a thickness of about 1.0 μm.
The insulating films 21 and 21A are, for example, SiO ₂ films and have a thickness of about 0.1 μm.

A method of manufacturing the magnetic sensing element of this embodiment will be described with reference to FIGS. 4, 5 and 6. 6A to 6D are cross-sectional views of the respective manufacturing steps shown in the same cross section as FIG. A soft magnetic film is formed on the substrate 10 and is removed by etching, leaving a strip-shaped portion to be the magnetic film 33 in FIG. The SiO ₂ insulating film 21 having a thickness of about 0.1 μm is formed on the magnetic film 33. A conductor film 36F made of copper or the like is formed on the insulating film 21, and the conductor 36 is left by etching as shown in FIG.

After forming the insulating film 21A (preferably a SiO ₂ film) on the conductor 36, a magnetic film 34A having substantially the same thickness as the conductor 36 is formed on the insulating films 21 and 21A. As shown in FIG. 6C, when the protruding portion of the magnetic film 34A is removed, the magnetic film 34 divided by the conductor 36 is obtained. An insulating film 21A made of a SiO ₂ film is further formed on the magnetic film 34.
And a magnetic film 35 is further formed on the insulating film 21A as shown in FIG. As shown in FIG. 6 so as to be connected to the conductors 36B at positions slightly apart from both ends of the magnetic film 35.
Then, a conductor film (not shown) such as copper having a thickness of about 2.0 μm to be the electrodes 11 and 12 shown in FIG. 4 is formed. By etching the conductor film, the electrodes 11 and 12 are left and the other portions are removed to complete the magnetic sensing element of this embodiment.

In this embodiment, as shown in FIG. 5, when the magnetic detecting element is in the external magnetic field 30, in the end region 40A of the magnetic pole 40, the magnetic flux is the magnetic films 33, 3 as shown by the arrows.
4 and 35 are dispersed and passed so that the magnetic flux density per cross-sectional area in the thickness direction becomes uniform. The length of the arrow indicates the magnetic flux density. Since the thickness of the magnetic film 34 is twice the thickness of the magnetic films 33 and 35, the magnetic flux passing through the magnetic film 34 is almost the same as the total magnetic flux passing through the magnetic films 33 and 35. In the central region 40B of the magnetic pole 40, the magnetic flux of the magnetic film 34 is divided into two and flows into the magnetic films 33 and 35, so that the magnetic flux densities of the magnetic films 33 and 35 are doubled. That is, in the vicinity of the conductor 36, the strength of the external magnetic field apparently doubles. As a result, the high frequency power supply 1 is placed between the electrodes 11 and 12.
00, a high-frequency voltage is applied, and when the high-frequency current is passed through the conductor 36, the change in impedance due to the external magnetic field 30 increases, and high detection sensitivity is obtained.

The magnetic films 33 and 34 shown in FIG. 5 of the second embodiment.
Or 35 is necessarily a single layer membrane as shown
No need. For example, the frequency band to be used,
Depending on the shape of the magnetic pole
Even if a multilayer structure as shown in detail in (b) and FIG. 8 is adopted
good. For example, as shown in FIG.
The magnetic films 33, 34, and 35 electrically insulated by 1A are
For example, a very thin non-magnetic insulating film 120 (having a thickness of 5 nm)
The thin horizontal line in each magnetic film
5nm thick SiO _TwoInsulating film) in the thickness direction (Fig. 7)
Magnetically cut in the vertical direction in (a). do this
Between the upper and lower layers of the magnetic film formed by cutting
Bonds are created, and reflux domains are less likely to occur on the magnetic film surface.
This has the effect of stabilizing the magnetic domain structure. To this
Therefore, the width of the magnetic poles (from (a) in FIG.
When the (dimension in the direction of
Since the area is not disturbed, it is easy to obtain a stable and high magnetic permeability.
It As a result, a high sense is obtained even with a narrow magnetic pole with a small demagnetizing field.
It is possible to obtain a magnetic detection element having a degree.

On the other hand, as in the modified example of FIG. 7 (b), the upper and lower parts of the above structure are made thicker (thickness allowing electrical insulation).
Through the non-magnetic insulating films EI2 and EI1 of
1, 352 are provided for the magnetic films 331, 332, 341,
You may comprise the magnetic pole by 342, 351, 352.
By electrically insulating each magnetic film with the insulating film 121, so-called eddy current loss can be prevented.
Magnetic films 331, 332, 341, 342, 351, 35
2 are non-magnetic insulating films 107b, 106b and 10 respectively.
5b, 103b, 102b and 101b are magnetically separated. The conductors 104a and 104b are the conductors 3 of FIG.
Equivalent to 6. As a result, the narrow magnetic pole having a small demagnetizing field as described above can be driven at a higher frequency. Since the impedance increases in proportion to the frequency, higher sensitivity can be obtained in this case than in the above example.

FIG. 8 shows an example of the dimensions of each part as a preferred embodiment by enlarging the part indicated by VIII in FIG. 7 (b). In addition, each part is shown with a reference numeral corresponding to FIG. The magnetic films 33F, 34F and 35F correspond to the magnetic films 33, 34 and 35 of FIG. 5, respectively.
The insulating films 21E and 21F are insulating films 21 and 21 respectively.
Corresponds to A. As shown in FIG. 8, the magnetic film 33F,
34F and 35F are very thin 5 nm Si, respectively.
It is divided into upper and lower layers by nonmagnetic insulating films 101b to 107b for stabilizing O ₂ magnetic domains. In addition, the through electrical conductor 104b
The upper and lower nonmagnetic insulating films EI2 and EI1 additionally provided above and below and having a thickness (0.1 μm) capable of electrical insulation have a great effect of preventing eddy current loss. Further, the second insulating film 21 second from the bottom and the second insulating film 21A second from the top each are SiO ₂ films having a thickness of 0.1 μm to insulate the through conductor 104b. In this embodiment, as shown in FIG. 5, since the thickness of the magnetic film 34 and the thickness of the conductor 36 are substantially the same, the surface of the uppermost magnetic film 35 is substantially flat except for a small recess 35A. is there. That is, since there is no large unevenness like the stepped portion 4D shown in FIG. 16B of the prior art, it is possible to avoid a decrease in magnetic permeability due to it, and it is possible to realize a magnetic detection element having high magnetic permeability. The higher the magnetic permeability of the magnetic pole 40, the higher the magnetic flux density in the central region 40B even with the same external magnetic field. Therefore, the impedance change of the conductor 36 becomes large and the detection sensitivity becomes high.

The magnetic pole 40 of the second embodiment is replaced with the magnetic pole 20 of FIG.
You may arrange | position in parallel like A-20D.
By doing so, the conductors 3 of the plurality of magnetic poles 40 are respectively formed.
Since 6 are connected in series, the impedance change due to the external magnetic field increases in proportion to the number of magnetic poles 40.

<< Third Embodiment >> A magnetic sensor 100 according to a third embodiment of the present invention will be described with reference to FIGS. 9 and 10. FIG. 9 is a plan view of the magnetic detection element of this embodiment.
FIG. 10 is a cross-sectional view of one magnetic pole shown in FIG. 9, for example, the magnetic pole 51 taken along the line XX. As shown in FIG. 9, conductive electrodes 43 and 44 having a thickness of about 2.0 μm are provided at a predetermined interval on a non-magnetic insulating substrate 10 such as ceramics. Between the electrodes 43 and 44, for example, six magnetic poles 51, 52, 53, 54, 55, 56 are arranged in parallel with a constant space. Magnetic poles 51-56
All have substantially the same shape, one of which, for example, the magnetic pole 51, is shown in cross-section in FIG.

In FIG. 10, the magnetic pole 51 has conductors 47A and 48A at two positions. The conductors 47A and 48A and the magnetic films 50, 57A, 57B, 57C and 5 in the vicinity thereof
The structure of 8 is substantially the same as the structure of the conductor 36 of FIG. 5 and its vicinity. The conductor 47A on the right side of each of the electrodes 51 to 56
Are connected to each other in series by connecting conductors 47. The conductor 48A on the left side of each of the electrodes 51 to 56 is the connection conductor 48.
Several are connected in series with each other. Conductor 4 of electrode 51
7A and the conductor 48A of the electrode 56 are connected by the connection conductor 45. The electrode 4 is formed by the connecting conductors 45, 47 and 48.
A current path from 3 to the electrode 44 is formed. The number of the magnetic poles 51 to 56 shown in FIG. 9 is not limited to six, and may be smaller or larger than six.

The operation of this embodiment will be described below.
In FIG. 9, when a high-frequency voltage from the high-frequency power source 100 is applied between the electrodes 43 and 44, the electrodes 43 are connected to the conductors 4 respectively.
7, a current that is inversely proportional to the impedance of the current path flows through the current path that reaches the electrode 44 through the conductors 47A, the connection conductors 45, the conductors 48, and the conductors 48A.

The magnetic field detected by the magnetic detecting element 110 of this embodiment is shown in FIG. When the entire magnetic detection element 110 is placed in the substantially uniform external magnetic field 30, magnetic flux passes through the magnetic poles 51 to 56 in the same manner as that shown in FIG. 5 of the second embodiment. Thereby, each magnetic pole 51-56
The impedances of the conductors 47A and 48A are reduced. As a result, the impedance between the electrodes 43 and 44 is reduced and the external magnetic field can be detected.

In this embodiment, the conductors 47A and 48A are provided at two positions on each of the magnetic poles 51 to 56, and the conductors 47A and 48A of each of the magnetic poles 51 to 56 are connected in series.
The change in impedance due to the external magnetic field 30 is significantly increased. In the example of FIG. 9, 12 times (6 ×
2). As a result, the sensitivity of magnetic detection is increased by 12 times.

<< Fourth Embodiment >> A magnetic sensor according to a fourth embodiment of the present invention will be described with reference to FIG. The substantial structure of the magnetic sensing element of this embodiment is the same as that of the second embodiment shown in FIG. FIG. 11 is a cross-sectional view of the magnetic pole 60 of the magnetic detection element of this embodiment, which corresponds to the cross-sectional view of FIG. The present embodiment relates to a method of passing a DC current to give a DC bias magnetic field to the magnetic pole 60. In the method shown in FIG. 11A, a direct current is passed through the magnetic film 33 immediately below the conductor 36. In order to pass a DC current, the feeding point 61 of the magnetic film 33 directly below the conductor 36 is connected to the positive electrode of the DC power source, and the feeding point on the back side (position on the back side of the paper) of the magnetic film 33 which is not visible in the figure is the negative electrode. Connect to. This causes a current to flow from the front to the back of the paper. The conducting wire connected to the feeding point 61 is formed on the insulating substrate 10 in the same width as the width of the conductor 36 in the left-right direction in the drawing in the portion of the magnetic film following the feeding point 61 in the etching process for forming the magnetic film 33. It can be made easily and easily by leaving it. Since only one feeding point 61 is provided on the magnetic film 33, the structure is simple. However, the DC bias magnetic field applied to the magnetic pole 60 is somewhat non-uniform.

In the method shown in FIG. 11B, the magnetic film 3
The two feeding points 62 and 63 of the conductor 3, which are slightly separated from the conductor 36.
Is connected to the positive electrode of the DC power supply, and the magnetic film 33 not visible in the figure
The two feed points on the back side of the are connected to the negative electrode. As a result, an electric current is applied to the feeding points 62 and 63 from the front to the back of the paper surface. As a result, the DC bias magnetic field applied to the magnetic pole 60 becomes more uniform than in the case of FIG. Figure 11
In the method shown in FIG. 11C, the feeding point 6 in FIG.
In addition to 2, 63, the magnetic film 35 also has two feeding points 64,
65 is provided. A current is applied to the feeding points 62 and 63 from the front to the back of the paper, and a current is applied to the feeding points 64 and 65 from the back to the front of the paper. According to the method of FIG. 11C, the DC bias magnetic field becomes much more uniform than that of the method of FIG. 11B. According to this embodiment, a large DC bias magnetic field can be applied to the magnetic pole with a relatively small DC current.

<< Fifth Embodiment >> A magnetic detection element according to a fifth embodiment of the present invention will be described with reference to FIGS. 12
Is an oblique projection view of the magnetic detection element of the present embodiment, and FIG. 13 is a sectional view taken along line XIII-XIII of FIG. 10 and 11, electrodes 11 and 12 are provided on the non-magnetic insulating substrate 10 with a predetermined distance therebetween. A magnetic pole 70 is provided between the electrodes 11 and 12. The magnetic pole 70 is the magnetic film 3 formed on the insulating substrate 10 and having a thickness of about 0.5 μm.
3, and the insulating film 2 having a thickness of about 0.1 μm on the magnetic film 33.
The magnetic film 34 having a thickness of about 1.0 μm formed through
A, 34B. A conductor 36 is provided between the magnetic films 34A and 34B while keeping insulation between the magnetic films 34A and 34B. Magnetic films 34A, 34B and conductor 36
A magnetic film 72 having a thickness of about 0.5 μm is provided on the insulating film 21A via the insulating film 21A. The conductor 36 is electrically connected to the electrodes 11 and 12 via the connection conductors 74 and 75 formed on the insulating substrate 10. In this embodiment, the magnetic film 72 is formed only near the conductor 36.

Generally, when the magnetic film of the magnetic detecting element is placed in an external magnetic field, a demagnetizing field is generated in the magnetic film. It is known that the demagnetizing field is proportional to the total thickness of the magnetic film. In this embodiment, since the uppermost magnetic film 72 is provided only in the vicinity of the conductor 36, only the magnetic film 33 and the magnetic films 34A and 34B are formed in the portions other than the vicinity of the conductor 36, and the total thickness of the magnetic films is the above-mentioned. It is thinner than that of the example. As a result, the strength of the demagnetizing field also decreases, and the magnetic flux near the conductor 36 due to the external magnetic field increases. As a result, the impedance change of the conductor 36 also increases, and the sensitivity of magnetic detection improves. Since the magnetic film 72 near the conductor 36 does not have large irregularities, the magnetic permeability is also kept high,
From this point as well, the detection sensitivity is improved.

<< Sixth Embodiment >> A magnetic sensor according to a sixth embodiment of the present invention will be described with reference to FIG. FIG. 14 is a sectional view showing the same section as FIG. 13 of the fifth embodiment. In the figure, a thickness of about 0.5 is formed in the central region of the non-magnetic insulating substrate 10.
A magnetic film 81 of μm is formed. After forming the insulating film 82 having a thickness of 0.1 μm on the magnetic film 81, the conductor 36 is formed in the central portion. Magnetic films 83A and 83B are formed on the insulating film 82 except the conductor 36, and an insulating film 85 is formed on the conductor 36 and the magnetic films 83A and 83B. A magnetic film 86 is formed on the insulating film 85 near the conductor 36.
Is formed.

According to this embodiment, in the vicinity of the conductor 36,
Since the magnetic films 81, 83A, 83B and 86 are laminated, the total thickness of the magnetic films is about 2 μm. However, since the magnetic films 83A and 83B are the only left and right ends in the figure, the thickness is about 1 μm. Most of the magnetic pole 80 has a magnetic film thickness of 1
Since the thickness is as thin as μm, the strength of the demagnetizing field becomes smaller than that of the fifth embodiment. This effectively increases the external magnetic field and improves the sensitivity of magnetic detection. Further, if the film thickness of 83A and 83B is larger than the sum of the film thicknesses of the magnetic films 81 and 86, the magnetic flux density becomes large in the vicinity of the conductor 36, resulting in high sensitivity. FIG. 15 is a cross-sectional view showing a direct current feeding point for applying a DC bias magnetic field to the magnetic pole 80 of this embodiment. In the magnetic film 81, an electric current is applied to the two feeding points 88 from the front side to the back side of the paper surface, and the magnetic film 86 is set to 2 points.
An electric current is applied to one feeding point 89 from the back of the paper toward the front. As a result, a uniform DC bias magnetic field can be applied to the magnetic pole 80.

[0036]

As described in detail in each of the above embodiments, according to the present invention, three magnetic films are laminated via an insulating film to form a magnetic pole. When a high frequency current is passed through the current path formed in the magnetic film at the center of the magnetic pole and the magnetic pole is placed in an external magnetic field,
The impedance of the current path changes. Since the change in impedance corresponds to the strength of the external magnetic field, the strength of the external magnetic field can be detected. Since the surface of the magnetic pole has no large unevenness, the magnetic permeability is kept high, and the impedance change of the current path due to the external magnetic field becomes large. As a result, a magnetic detection element having high detection sensitivity can be obtained.

[Brief description of drawings]

FIG. 1 is a perspective view of a magnetic detection element according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a plan view of another example of the magnetic detection element of the first embodiment.

FIG. 4 is a perspective view of a magnetic detection element according to a second embodiment of the present invention.

5 is a sectional view taken along line VV of FIG.

6A to 6D are cross-sectional views showing a manufacturing process of the magnetic sensing element of the second embodiment.

FIG. 7 (a) is a sectional view of a modification of the embodiment of FIG. (B) Sectional view of still another modification of the embodiment shown in FIG.

FIG. 8 is an enlarged sectional view showing a detailed structure of a section of the embodiment of FIG. 7 (b).

FIG. 9 is a plan view of a magnetic detection element according to a third embodiment of the present invention.

10 is a sectional view taken along line XX of FIG.

11 (a), (b) and (c) are cross-sectional views showing various methods of supplying a DC current for applying a DC magnetic bias to the magnetic detection element of the fourth embodiment.

FIG. 12 is a perspective view of a magnetic detection element according to a fifth embodiment of the present invention.

13 is a sectional view taken along line XIII-XIII in FIG.

FIG. 14 is a sectional view showing a modification of the sixth embodiment.

FIG. 15 is a sectional view showing still another modification of the sixth embodiment.

16 (a) and 16 (b) are partial cross-sectional views of a prior art magnetic sensor.

[Explanation of symbols]

10 Insulating substrate 11, 12 Electrode 13, 14, 15, 33, 34, 35 Magnetic film 16, 17 Electrical connection part 20, 20A, 20B, 20C, 20D, 40, 51,
52, 53, 54, 55, 56, 60, 70, 80 Magnetic poles 21, 21A, 21E, 21F, 82, 85, 121
Insulating film 36 Conductors 36A, 36B Connection part 100 High frequency power source

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shoro Kuroe             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Ken Takahashi             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 2G017 AA01 AB07 AD51 AD65                 5E049 BA16 CB01

Claims (13)

[Claims] 1. A first soft magnetic film formed on an electrically insulating member, and a pair of first soft magnetic film formed on the first soft magnetic film via a first electrically insulating film. A second soft magnetic film having an electrical connection portion, a third soft magnetic film formed on the second soft magnetic film via a second electrically insulating film, and the pair of electrical connections Detection element having a pair of electrodes for connecting the unit to an external high frequency power supply. 2. A first soft magnetic film formed on an electrically insulating member, wherein a first electrically insulating film is formed on a part of the first soft magnetic film. A conductor, a second portion formed on the first soft magnetic film other than the portion on which the conductor is formed via an electrically insulating film
A soft magnetic film, a third soft magnetic film formed on the conductor and the second soft magnetic film via a second electrically insulating film, and connected to both ends of the conductor via connecting portions. A magnetic sensing element having a pair of electrodes for connecting the conductor to an external high frequency power supply. 3. A plurality of magnetic poles having the first soft magnetic film, the second soft magnetic film, and the third soft magnetic film are connected to each other in series at the electrical connecting portions. The magnetic detection element according to claim 1, wherein: 4. The first soft magnetic film, the second soft magnetic film,
3. The magnetic detecting element according to claim 2, wherein a plurality of magnetic poles having a conductor and a third soft magnetic film are connected in series by connecting the conductors to each other. 5. A plurality of first soft magnetic films formed in parallel on a member having electrical insulation, and a plurality of first soft magnetic films each having a predetermined electrical insulating film on each of the first soft magnetic films. At least 2 formed with a separation distance of
Two conductors, a second soft magnetic film formed on each part of the first soft magnetic film except the part where the conductor is formed via an electrically insulating film, the conductor and the second soft magnetic film. A third soft magnetic film formed on the second soft magnetic film via an electrically insulating film, and the at least two conductors formed on each of the first soft magnetic films are connected in series. A magnetic detection element having a connecting portion and an electrode connected to both terminals of the connecting portion. 6. The magnetic detection element according to claim 1, wherein the third soft magnetic film is formed only in the vicinity of the electrical connection portion. 7. The first soft magnetic film is formed only in the vicinity of the electrical connection portion.
The magnetic detection element described. 8. The magnetic sensing element according to claim 2, wherein the third soft magnetic film is formed only near the conductor. 9. The second soft magnetic film is formed only in the vicinity of the conductor.
The magnetic detection element described. 10. The thickness of each of the first and third soft magnetic films is about one half of the thickness of the second soft magnetic film. Magnetic detection element. 11. The first, second, and third soft magnetic films are films in which a plurality of soft magnetic films and electrically insulating films are alternately laminated, respectively. 2. The magnetic detection element according to 2 or 5. 12. A step of forming a rectangular first soft magnetic film on an insulating substrate, a step of forming an electric insulating film on the first soft magnetic film, and an upper surface of the electric insulating film. A step of forming a soft magnetic film on the entire surface of the insulating substrate;
Removing the other portion, leaving a pair of connection portions for connecting between the soft magnetic film and the second soft magnetic film and the electrode formed in a later step, Forming an electric insulating film on the film, forming a third soft magnetic film on the electric insulating film, and forming a second soft magnetic film on the insulating substrate at a predetermined distance. And a step of forming a pair of electrodes so as to be respectively connected to the connection portions of. 13. A step of forming a rectangular first soft magnetic film on an insulating substrate, a step of forming an electrical insulating film on the first soft magnetic film, and a conductive layer on the electrical insulating film. Forming a body film, leaving the conductor film only in the central portion on the electrical insulating film, and from the remaining conductor in the central portion substantially perpendicular to the rectangular first soft magnetic film. A step of forming a pair of connecting portions with a conductor by removing the other by etching to leave a pair of connecting portions for extending and being connected to electrodes formed in a later step, and an electric insulating film on the conductor A step of forming a soft magnetic film on the electric insulating film, a step of etching away the soft magnetic film near the conductor, and an electric insulating film formed on the conductor and the soft magnetic film. Step of the insulating film Forming a third soft magnetic film,
And a step of forming a pair of electrodes on the insulating substrate so as to be electrically connected to the pair of connecting portions at a predetermined distance from each other, respectively.