JPH11112056A - Magnetic field sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic field sensor which has a simple structure, low manufacturing cost and high detection sensitivity and displays a radiation action enough for radiating the heat from a thin film pattern for detecting the magnetic field during operation, which is a serious problem when using a low-thermal-conductivity substrate. SOLUTION: A sensor comprises a resin-made flexible substrate 10 of 5-300 μm and magnetic field-detecting thin film pattern 20 on one side of the substrate 10 having a detecting face at the other side facing an object. A more preferred embodiment has a heat radiator 50 of 200 μm or more on the film pattern 20; the radiator having a thermal conductivity of 20 W/mK or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic field sensor having a thin film pattern as a magnetic field detecting element for converting a change in an external magnetic field into an electric signal, and more particularly to a magnetic field sensor used for detecting rotation and position.

[0002]

2. Description of the Related Art A magnetic field sensor is a device that converts a change in an external magnetic field into an electric signal, and patterns a ferromagnetic or semiconductor thin film, applies a current to the thin film pattern, and changes the external magnetic field as a voltage change to an electric signal. It is provided with the element which converts into. For example, a magnetoresistive element is an element that measures a magnetic field intensity using a phenomenon (electric resistance, MR effect) in which the electric resistance of a ferromagnetic metal changes due to an external magnetic field. In the case of a single-layer magnetic film, the magnetic anisotropic magnetoresistance effect of a ferromagnetic metal film, which has been known for a long time, has been used. However, recently, a giant magnetoresistance effect element having a multilayer structure has been reported. For example, in the National Technical Report, Vol. 42, No. 4, page 465, (NiFeCo
/ Cu) V using multilayer film as giant magnetoresistive element
A TR capstan motor rotation detection sensor is introduced. Also, National Technical Report, Volume 42, 4
, Page 84, discloses a semiconductor magnetic field detection sensor using an InSb thin film.

[0003]

FIG. 6 shows a general structure of a conventional magnetic field sensor. As shown in FIG. 6, a thin film pattern 120 for detecting a magnetic field and an electrode 130 connected to the thin film pattern 120 are formed on one side surface 110a of the substrate 110, and a protection for further protecting the element is formed on these. A film 108 is provided.
Surface side, that is, the substrate surface 1 on which the thin film pattern 120 is formed
The structure in which the 10a side is opposed to the detection target 170 has been adopted. Further, in the conventional magnetic field sensor, the substrate 11
0, a through hole 133 is formed.
Through the conductor 133a filled into the substrate 3, solder bonding and lead wire connection on the back surface 110b of the substrate 110 have been performed. This is to improve the sensitivity by minimizing the distance G1 between the thin film pattern 120 and the detection target 170. If the solder joints or the lead wires are protrudingly formed on the surface of the substrate 110, the distance G1 cannot be reduced.

However, such a through hole 13
3, the structure for forming the protective film 108 on the thin film pattern 120 is extremely complicated, the productivity is low, and the production cost increases. In addition, it is not preferable to form the protective film 108 too thick in order to improve the sensitivity, and the formed protective film 108 itself is not so strong and may cause a problem in terms of weather resistance. In FIG. 6, reference numeral 160 denotes a permanent magnet, and the permanent magnet 160
1 is filled and sealed.

Further, as a prior art related to the present invention, there is Japanese Patent Application Laid-Open No. 63-196874, in which a thin film pattern for detecting a magnetic field is provided on one side of the substrate surface and the other side of the substrate is provided. A magnetoresistive sensor is disclosed in which the back surface is a detection surface facing the object to be detected.
According to this, the swelling or the like of the connection portion is eliminated, so that the distance to the object to be detected can be reduced and the sensitivity can be increased. Further, from the manufacturing point of view, it is said that a sensor can be manufactured with good yield and at low cost.

[0006] However, Japanese Patent Application Laid-Open No. 63-1968 discloses such a method.
The substrate disclosed in Japanese Patent No. 74 is a glass substrate,
Since this is relatively easily broken, a thin glass substrate cannot be used from the beginning. Therefore, after providing a thin film pattern for magnetic field detection on a relatively thick substrate, the substrate must be thinned by grinding, polishing, and etching the back surface portion of the glass substrate. Is extremely complicated. Further, the mechanical strength is unstable because the processed glass substrate is thin, and there is a possibility that the glass substrate may still be damaged by a slight vibration during the process. Further, the prior art does not consider any means for radiating heat from the thin film pattern for detecting a magnetic field during operation.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a magnetic field sensor having a simple structure, which can be manufactured at low cost, and which has high detection sensitivity. is there. Another object of the present invention is to provide a magnetic field sensor that can exert a sufficient heat radiating effect on heat generated from a thin film pattern for detecting a magnetic field during operation, which is a major problem when a substrate having low thermal conductivity is used. .

[0008]

In order to solve such a problem, the present invention relates to a magnetic field sensor having a thin film pattern for detecting a magnetic field on a substrate, wherein the magnetic field sensor has a thickness of 5 mm. A thin film pattern for detecting a magnetic field is formed on one surface of a flexible substrate made of resin having a thickness of about 300 μm, and the other surface of the flexible substrate is configured as a detection surface that is used to face a detection target.

In a preferred embodiment of the magnetic field sensor of the present invention, a heat radiating member having a thickness of 200 μm or more is formed on the thin film pattern, and the heat radiating member has a heat conductivity of 20 W · m ⁻¹ ·. It is configured to be greater than or ^{equal to} K- ¹ .

In a preferred embodiment of the magnetic field sensor according to the present invention, the resin flexible substrate is configured to be a polyimide film.

In a preferred embodiment of the magnetic field sensor according to the present invention, the thickness of the resin-made flexible substrate is 20 to 1
It is configured to be 00 μm.

In a preferred embodiment of the magnetic field sensor according to the present invention, the thin film pattern for detecting the magnetic field is a magnetoresistive film.

In a preferred embodiment of the magnetic field sensor according to the present invention, the thin film pattern for detecting the magnetic field is constituted by a giant magnetoresistive film composed of a multilayer film.

In a preferred embodiment of the magnetic field sensor according to the present invention, the resin-made flexible substrate is provided with a thin film of an inorganic material on a surface thereof.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional structural view showing a magnetic field sensor 1 according to a preferred embodiment of the present invention.

As shown in FIG. 1, the magnetic field sensor 1 of the present invention has a thin film pattern 20 for detecting a magnetic field on a substrate 10. The substrate 10 according to the present invention has a thickness of 5 to 5.
A flexible substrate made of resin having a thickness of 300 μm, a thin film pattern 20 for detecting a magnetic field is formed on one surface 10 a, and the other surface 10 b of the flexible substrate 10 is opposed to the detection target 70. That is, the other surface 10 of the flexible substrate 10 on which the thin film pattern 20 is not formed
b is configured as a detection surface 10b facing the detection target 70.

At both ends of the thin film pattern 20, electrodes 30 for passing a current are usually provided, and these electrodes 30 are connected to lead wires 35 by using solder 34.

On the thin film pattern 20, a heat radiating member 50 is formed as shown in a more preferred embodiment. A permanent magnet 60 is fixed on the heat radiating member 50, and a shield case 65 is provided around the permanent magnet 60.
Surrounded by From the permanent magnet 60 to the detected object 70
This is to prevent leakage of magnetic flux in directions other than the direction of arrow α toward. The space between the heat radiating member 50 and the shield case 65 is sealed with a resin 61 having a high thermal conductivity to assist heat radiation. Further, the permanent magnet 60 is provided with a shield case 65 for transferring the heat from the heat radiating member 50 to the outside and releasing it.
Is adhered to. That is, the heat generated in the thin film pattern 20 is transferred from the heat radiating member 50 to the permanent magnet 60 and from the permanent magnet 60 to the shield case 65 and radiated.

As shown in FIGS. 1 and 2, the thin film pattern 20 has a rotating body gear 70 which is an example of the detected body 70.
From the air gap G2. The rotator gear 70 is made of, for example, a soft magnetic stainless steel SUS430 material, and is affected by a magnetic field emitted from the permanent magnet 60. That is, with the rotation of the rotating body gear 70, the magnetic field changes due to the positional relationship of the unevenness formed on the gear surface. The change in the magnetic field is detected by the thin film pattern 20 to detect the rotation amount of the rotating body gear 70. The change in the magnetic field performed from the permanent magnet 60 via the rotating gear 70 is determined by the rotating gear 70 and the thin film pattern 2 for detecting the magnetic field.
The smaller the distance G1 of 0, the higher the sensitivity.

In the magnetic field sensor 1 of the present invention, the flexible substrate 10 itself functions as an original substrate and as a protective film. In addition, the degree of the function as a protective film is much better than that of the conventional one. That is, the conventional protective film is formed under a relatively mild condition so as not to damage the thin film pattern, since the thin film pattern for detecting the magnetic field is formed and then formed thereon. Therefore, the properties inherent in the protective film material cannot often be exhibited. On the other hand, since the protective film of the substrate 10 that functions in the present invention is first manufactured in advance as the substrate 10, there is no need to consider the damage of the thin film pattern and the like, and the characteristics inherent to the material are possessed. It is possible to fully demonstrate.

In the present invention, unlike the conventional structure, it is necessary to use the substrate 10 having a small thickness. This is because, as is apparent from FIG. 1, the substantial gap distance G1 is the sum of the air gap distance G2 and the thickness T of the substrate 10.

Therefore, the thickness of the base 2 is preferably in the range of 5 to 300 μm, as described above, and particularly preferably in the range of 20 to 100 μm. When the thickness is less than 5 μm, it is difficult to handle the substrate as a substrate from the viewpoint of manufacturing, and there is a disadvantage that a sufficient function as a protective film cannot be achieved. If the thickness exceeds 300 μm, there is a disadvantage that the substantial gap distance G1 increases and the output decreases.

The substrate 10 used in the present invention is preferably a thin and light plastic film having excellent flexibility. More specifically, various materials known as plastic film materials, for example, polyimide, polyethylene terephthalate (PET), polypropylene (P)
P), Teflon, etc. can be used. In particular, it is preferable to use polyimide having high heat resistance in consideration of joining by solder at the end of the electrode 30. Further, as for polyimide, a substrate having a small surface roughness can be obtained at low cost.
Polyimide has excellent impact resistance and has a very low risk of being damaged by handling in the manufacturing process even if it is 300 μm or less.

The substrate 10 may be composed of only one kind of material, for example, only polyimide which is an organic substance. In particular, when high reliability is required, the surface on which the thin film pattern 20 for detecting the magnetic field is provided, Alternatively, an inorganic thin film such as silicon oxide having a function as a protective film may be provided on the opposite surface by a sputtering method or a sol-gel method.
In this case, the weather resistance is improved due to the presence of the inorganic thin film, but the main part of the substrate 10 is also composed of a resin substrate, and such a laminated substrate is also within the scope of the “resin flexible substrate” in the present invention. It is something that enters.

As described above, the substrate 10 according to the present invention is not limited to the one made of a single material. Even if a plurality of materials are laminated, the substrate 10 may be regarded as the substrate of the present invention.
In the case of such a laminate structure, the film thickness of the substrate 10 indicates the total thickness of each layer constituting the laminate, and this thickness needs to be within the scope of the present invention.

The flexible substrate 10 made of resin such as polyimide used in the present invention has low thermal conductivity. For this reason, in the case of a usage method in which heat generation from the element of the thin film pattern 20 becomes large, heat dissipation becomes insufficient, the temperature of the element rises, and eventually the element is broken.
From such a viewpoint, the heat radiation member 50 is formed on the thin film pattern 20 of the present invention. The heat dissipating member 50 has a heat conductivity of 20 W in order to sufficiently exhibit its heat dissipating function.
It is preferable that the heat radiation member has a thickness of at least m ^-1 · K ^-1 and a thickness of at least 200 µm. Thermal conductivity is 20W ・ m ^-1・ K ^-1
If the thickness is less than 200 μm or the thickness is less than 200 μm, a sufficient heat radiation effect cannot be expected.

The heat dissipating member 50 is preferably formed directly on the thin film pattern 20, but is formed via an adhesive material having a film thickness of 10 μm or less (having a thermal conductivity of 20 W · m ⁻¹ · K ⁻¹ or less). May be. This is because an adhesive material or the like having a thickness of 10 μm or less does not adversely affect heat transfer because the thickness is small even if the thermal conductivity is 20 W · m ⁻¹ · K ⁻¹ or less. However, it is preferable that the thermal conductivity is as high as possible. In particular, it is preferable to use a silicon resin and further a resin in which insulating solid fine particles having a high thermal conductivity are dispersed in the silicon resin.

Suitable materials for the heat radiating member 50 include various metal materials (for example, aluminum, copper, gold, etc.), diamond, and ceramic materials having high thermal conductivity.
These heat dissipation materials are preferably formed directly on the thin film pattern 20 as a thin film by a vacuum film forming method such as a sputtering method, but may be formed so that a bulk material is adhered through an adhesive. . The portion of the heat radiating member 50 that comes into contact with the external atmosphere may be formed with irregularities on its surface in order to increase the heat radiating area and increase the heat radiating efficiency.
Since the heat radiating member 50 is formed on the thin film pattern 20, it does not hinder the detection of the magnetic field in the positional relationship with the object to be detected.

The magnetic field sensor 1 of the present invention is shown in FIGS.
Is preferably used for the rotation detection as shown in FIG. 2, and in particular, the distance from the detection target 70 to the thin film pattern 20 for detecting the magnetic field, that is, the substantial gap distance G
When 1 (FIG. 1) is 3 mm or less, high output characteristics can be obtained. When the substantial gap distance G1 exceeds 3 mm, the detected output decreases. The lower limit of the substantial gap distance G1 is not particularly limited, and it is desirable that the gaps be installed as close as possible. However, in order to avoid contact with the magnetic field sensor 1 due to the rotational fluctuation of the rotating detection target 70, the substantial gap distance G1 is set. The lower limit of G1 is preferably set to about 0.1 mm.

As shown in FIG. 3, the magnetic field sensor 1 of the present invention has four thin film patterns 20 (magnetic field detection patterns 2).
0), and it is preferable that these four thin film patterns 20 form a so-called bridge circuit. That is, four thin-film patterns 20 (magnetic field detection patterns 20) having resistances of R1, R2, R3, and R4 are formed, and R1 and R4 simultaneously change resistance by a magnetic field, and R2 and R3 simultaneously have a time lag therefrom. A differential output can be obtained by arranging them so that the resistance changes. That is, when the magnetic field pitch is λ (FIG. 2), it is widely known that high output can be obtained by setting the magnetic field detection pattern interval W (FIG. 4) to λ / 4 or λ / 2. In addition,
In FIG. 3, reference numeral 29 indicates a power supply.

Further, when forming a bridge circuit, as shown in FIG. 4, a set in which thin film patterns of resistors R1 and R4 are formed in substantially the same place, and a thin film pattern of resistors R2 and R3 are formed in substantially the same place. The set W
It is preferable to form one bridge circuit with a total of four magneto-sensitive patterns. This is because the number of elements that can be manufactured from one substrate can be increased. In FIG. 4, the thin film pattern (magnetic field detection pattern) is simplified and represented by a single line in the drawing. However, in practice, the thin film pattern must be bent as shown in FIG. Is common. This makes it easier to obtain high output. FIG.
4 is a set on the left side of FIG. 4, that is, a set in which thin-film patterns of the resistors R1 and R4 are formed in substantially the same place, and has a bent shape. FIG. 5 shows a shape incorporating a device for finely adjusting the resistance of the magnetic field detection pattern at the final stage. That is, in the bridge circuit, it is important that the four resistors be equal in the initial state. For this purpose, for example, in FIG. 5, in order to finely adjust the resistance R1 between the electrode 30a and the electrode 30b, a part 20 of the adjustment electrode provided on the left side of the pattern is used.
By cutting a with a laser or the like, the resistance of R1 can be increased. Similarly, to increase the resistance R4 between the electrode 30c and the electrode 30d, a part 20b of the adjustment electrode is cut.

It is preferable that the thin film pattern 20 (magnetic field detection pattern 20) as a magnetic sensing pattern that can be used in the present invention uses a ferromagnetic material. In particular, it is preferable to use a thin film having a giant magnetoresistance effect. This is because the magnetic field sensitivity is high and the current direction and the magnetic sensing direction are not specified. The giant magnetoresistive film is a metal artificial lattice (Hiroshi Fujimori,
As described on page 347 of Agne Technology Center (published in 1995), it is a multilayer film of a ferromagnetic material and a non-magnetic material, and it is known that resistance changes due to a change in interface scattering of the multilayer film.

As the giant magnetoresistive film, an antiferro (coupling) type having a (ferromagnetic / non-magnetic conductor) structure,
(High coercivity ferromagnetic / non-magnetic conductor / low coercivity ferromagnetic) Inductive ferri (non-coupling) type, (antiferromagnetic /
It is roughly classified into a spin valve type having a (ferromagnetic material / non-magnetic conductor / ferromagnetic material) structure and a non-solid solution type granular type of Co / Ag system.

These giant magnetoresistive films have the following structures:
The detectable magnetic field strength, that is, the saturation magnetic field strength of the magnetoresistive effect greatly differs depending on the composition. For example, (Fe / C
r) antiferro type, 10 KOe or more, (CoNi
0.1 to 1 kOe for Fe / Cu) antiferro type
Hereinafter, about 5 to 20 Oe for the (NiFe / Cu / Co / Cu) -based induction ferri type, (FeMn / NiFe / Cu)
A (/ NiFe) -based spin valve type can detect a magnetic field of several Oe, and a granular type can detect a magnetic field of about 100 to 5 kOe. The magnetic field sensitivity is obtained by dividing the maximum magnetoresistance change rate by the saturation magnetic field strength. Even if the maximum magnetoresistance change rate is large, the magnetic field sensitivity is poor when the saturation magnetic field is large.
Conversely, even when the maximum magnetoresistance ratio is small, the magnetic field sensitivity is good when the saturation magnetic field is very small. For this reason, the basic form is selected from various giant magnetoresistive films so that the highest magnetic field sensitivity is obtained depending on the magnetic field strength to be detected, the composition system is changed, and the fine structure is optimized.

Such a thin film pattern 20 (magnetic field detection pattern 20) is formed by a vacuum film forming method, for example, a vapor deposition method, a sputtering method or the like.

[0037]

EXAMPLES Hereinafter, the present invention will be described in more detail by showing specific examples of the present invention.

Example 1 A 3 inch diameter, 75 μm thick polyimide film was used as a substrate. On this substrate, 200 ° -Ti (15 °)
-NiFeCo / 20Å-Cu) × 30 multilayer GMR films were formed. Here, the film structure is first 200 Ti, then 15 NiFeCo alloy and 20 Cu, in that order.
This is a multilayer film having a total thickness of 1250 °, which is laminated by 0 layers. Each of the targets used had a target composition of 99.9% or more in purity, and was evacuated to a final pressure of 4 × 10 ⁻⁷ Torr, and then an argon gas was introduced. The degree of vacuum during the film formation was 1.4 × 10 ^{−. 4} Torr. The substrate was water-cooled during the formation of each film.

After the film formation, a thin film pattern as a magneto-sensitive pattern is formed by a photolithography technique.
Separated into individual devices. Thin film pattern (magnetic sensing pattern)
Was formed by bending a rectangle having a width of 25 μm and a length of 3000 μm three times so as to form a line gap of 25 μm, and an electrode portion formed at the end of the thin film pattern had a size of 150 μm square. For the differential operation, the above two patterns are combined patterns formed in substantially the same place, and the interval D (D = 3.1
5 mm) to form a similar combination pattern, and a total of four magneto-sensitive patterns constituted one bridge circuit.

After being separated into individual devices by a processing process, the devices were soldered and lead wires were connected. And
On the thin film pattern (magnetic sensing pattern), a copper lump having a size of 2.5 mm square was fixed as a heat radiating member with a silicon adhesive. Donut-shaped SmC on a copper lump as a heat dissipation member
oFix a permanent magnet (outer diameter 2D, inner diameter D, thickness 0.5D) in a predetermined position, put it in a permalloy shield case, fill and seal the inside of the shield case with resin, complete the magnetic field sensor, and execute The sample of Example 1 was used. According to the cross-sectional observation, the thickness of the silicon adhesive was about 3 μm.

Example 2 The thickness of the polyimide film used as the substrate in Example 1 was changed to 20 μm. Other than the above, the second embodiment is the same as the first embodiment.
Was prepared.

Example 3 The thickness of the polyimide film used as the substrate in Example 1 was changed to 100 μm. Otherwise, the procedure of Example 1 was repeated to prepare a sample of Example 3.

A gear made of SUS430, which is an object to be detected, was attached to a rotation shaft whose rotation was detected. Specifically, a gear having a diameter of 61 mm and 48 teeth was used.

When rotation was detected at 300 rpm using the samples of Examples 1, 2, and 3, respectively, the outputs shown in Table 1 were obtained. The air gap distance G2 was set as shown in Table 1.

[0045]

[Table 1] Comparative Example 1 The polyimide film used as the substrate in Example 1 was changed to a glass substrate having a thickness of 200 μm. Otherwise, the procedure of Example 1 was repeated to produce a sample of Comparative Example 1. As a result, many cracks occurred in the glass substrate during the manufacturing process, and the quantity finally obtained as an element sample was smaller than that of Example 1 with the same substrate size.
It was less than 1/10 of the sample. The characteristics of the sample of Comparative Example 1 which could be slightly produced were almost the same as those of the sample of Example 1.

Comparative Example 2 The thickness of the polyimide film used as the substrate in Example 1 was changed to 4 μm. Otherwise, the procedure of Example 1 was repeated to produce a sample of Comparative Example 2. As a result, wrinkles occurred in the polyimide film during the manufacturing process, and an element sample could not be finally completed.

(Comparative Example 3) In Comparative Example 3, a sample of Comparative Example 3 was prepared in which the thin film pattern side formed on the substrate as the magnetically sensitive pattern was used as a detection surface to be used facing the object to be detected. When performance evaluation similar to that of the first embodiment was performed using this, the air gap distance G2 was set to 2 m.
m and cannot be less than 100 mV
It was below.

COMPARATIVE EXAMPLE 4 A through hole was previously formed in an alumina substrate, and the through hole was filled with a silver-palladium paste to prepare a conventional substrate having a through hole in which the front and back of the substrate were electrically connected. Using this substrate, a thin film pattern was formed in the same manner as in Example 1. On this thin film pattern, a polyimide resin was applied to a thickness of 30 μm and dried to form a protective film, which was then cut and assembled to complete a device of Comparative Example 4 sample. When the output was measured using this device, a device having the same level as in Example 1 was obtained. However, the time required to produce the comparative example 4 sample was:
It was about 5 times that of the sample of Example 1, and it was confirmed that the productivity was extremely poor. 85 ° C, 85 ° C
When the weathering test was performed for 1000 hours in an atmosphere of% relative humidity, the output was reduced to 70%. On the other hand, in the first embodiment, the output was hardly reduced.

REFERENCE EXAMPLE In the first embodiment, the heat radiation member was not formed on the thin film pattern as the magneto-sensitive pattern. Otherwise, in the same manner as in Example 1, a sample of Reference Example was produced. Using this sample of Reference Example and the sample of Example 1 described above, an experiment was conducted to compare the heat radiation effect. As a result, when the current was 5 mA, the characteristics were almost the same. However, when the current was 10 mA, the thin film pattern of the sample of the reference example was broken. On the other hand, in the sample of Example 1 described above, the thin film pattern did not break until the current of 15 mA was applied. That is, by adding a heat dissipation member to the polyimide film, the safety of the element can be further improved. Further, the allowable range of energization is widened, and application to a wide range of applications is possible.

[0050]

The effects of the present invention are clear from the above results. That is, the magnetic field sensor of the present invention has a thickness of 5 to 30 mm.
It has a thin film pattern for detecting a magnetic field on one surface of a resin-made flexible substrate of 0 μm, and the other surface of the flexible substrate is configured as a detection surface used to be opposed to an object to be detected. Consisting of
Moreover, it has high detection sensitivity. Further, as a more preferred embodiment, a heat radiating member having a thickness of 200 μm or more is formed on the thin film pattern, and the heat conductivity of the heat radiating member is 2 μm.
Since it is configured to be 0 W · m ⁻¹ · K ⁻¹ or more,
A sufficient heat radiating effect can be exhibited with respect to heat generated from the thin film pattern for detecting a magnetic field during operation. This allows
The safety of the element can be further improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view as a preferred embodiment of a magnetic field sensor according to the present invention.

FIG. 2 is a sectional view showing an example of use of the magnetic field sensor of the present invention.

FIG. 3 is a schematic diagram of a bridge circuit formed by a thin film pattern used in the magnetic field sensor of the present invention.

FIG. 4 is a schematic diagram showing a configuration example of a thin film pattern used for the magnetic field sensor of the present invention.

FIG. 5 is a schematic diagram showing a configuration example of a thin film pattern used for the magnetic field sensor of the present invention.

FIG. 6 is a cross-sectional view as one embodiment of a conventional magnetic field sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Magnetic field sensor 10 ... Flexible board made of resin 10b ... Detection surface 20 ... Thin film pattern 30 ... Electrode 50 ... Heat dissipation member 60 ... Permanent magnet 70 ... Object to be detected

Claims (7)

[Claims] 1. A magnetic field sensor comprising a thin film pattern for detecting a magnetic field on a substrate, wherein the magnetic field sensor is provided on one surface of a resin flexible substrate having a thickness of 5 to 300 μm for detecting a magnetic field. A magnetic field sensor having a thin-film pattern and serving as a detection surface used with the other surface of the flexible substrate facing the object to be detected. 2. A thin film pattern having a thickness of 200 μm
The magnetic field sensor according to claim 1, wherein a heat radiating member having a thermal conductivity of at least m is formed, and the thermal conductivity of the heat radiating member is at least 20 W · m ⁻¹ · K ⁻¹ . 3. The magnetic field sensor according to claim 1, wherein the resin flexible substrate is a polyimide film. 4. The thickness of the resin-made flexible substrate is as follows:
The magnetic field sensor according to any one of claims 1 to 3, wherein the magnetic field sensor has a thickness of 20 to 100 µm. 5. The magnetic field sensor according to claim 1, wherein the thin film pattern for detecting the magnetic field is a magnetoresistive film. 6. The magnetic field sensor according to claim 1, wherein the thin film pattern for detecting the magnetic field is a giant magnetoresistive film formed of a multilayer film. 7. The resin-made flexible substrate having a thin film of an inorganic material on a surface thereof.
The magnetic field sensor according to any one of the above.