JP2002071770A - Magnetic field detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a magnetic field detector whose sensitivity is high and whose sensitivity is adjusted easily. SOLUTION: A magnetic field effect that an impedance is increased as the magnitude of an external magnetic field as a component in the direction of a detection axis is increased and that the impedance is changed by a magnetic impedance characteristic which is reduced after passing a maximum value is used. A pulsed current is supplied via an oscillation circuit 13 and a differentiating circuit 14 to a magnetism-sensitive element 10 whose impedance is changed according to the external magnetic field. A voltage which is proportinal to the impedance across terminals of the magnetism-sensitive element is sensed by a switch 15 turned on in synchronization with the pulsed current and by a signal processing circuit 16 which holds a peak. A thin-film magnet 20 applies a bias magnetic field to the magnetism-sensitive element so that a region whose impedance is reduced as the magnitude of the external magnetic field at the magnetic impedance characteristic is increased is used as a measuring region. The output of the circuit 16 is compared with a prescribed level by a comparator 17.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly sensitive magnetic field detecting device. The present invention particularly relates to an apparatus capable of detecting a timing at which a magnetic field exceeds a predetermined level. As a specific application example, the present invention can be applied to a rotation sensor of an automobile ABS or a magnetic scale. INDUSTRIAL APPLICABILITY The present invention can be used for a detection device capable of detecting the presence of a minute magnetic field and detecting the reversal of the direction of the minute magnetic field with high accuracy.

[0002]

2. Description of the Related Art Conventionally, Hall elements, MR elements, magnetic pickups and the like have been known as sensors for detecting a magnetic field. However, since the detection sensitivity of these sensors is low, the detectable magnetic field is only about 1.4 × 10 ⁴ A / m. As a small element that detects the magnitude of a DC or low-frequency magnetic field with high sensitivity, one of the inventors of the present application has a diameter of 50 μm.
When a high-frequency current of 200 KHz or more is applied to an amorphous wire having a length of about m, a phenomenon was found in which the impedance of the wire greatly changed in accordance with an external magnetic field component parallel to the wire. A detection element that detects the magnitude of the external magnetic field itself using this principle has been proposed (Japanese Patent Application Laid-Open No. 7-181239).

Further, the same inventor has reported that a change in terminal voltage due to a change in impedance is caused by an external magnetic field of 0-400.
It has been found that in the range of A / m, two different external magnetic fields are taken for the same terminal voltage. Since this cannot uniquely determine a magnetic field in the vicinity of 0 to 400 A / m from the voltage between terminals, a directional sensor in which a DC bias magnetic field is applied to offset the zero point has been proposed (Japanese Patent Application Laid-Open No. HEI 9-260572). 7-248365).

[0004]

As described above, a high-sensitivity magnetic field detection sensor called a so-called magneto-impedance element has been proposed. Further, a magnetic field detection apparatus using this magneto-impedance element which can be applied to various uses. Development is required. Therefore, the present invention uses a special operation region in the change characteristic of the magnetic impedance with respect to the magnitude of the external magnetic field (hereinafter, referred to as “magnetic impedance characteristic”) to detect a magnetic field exceeding a predetermined level in a binary manner. It is an object to provide a magnetic field detection device. Another object is to realize a high-sensitivity magnetic field detection device capable of detecting a magnetic field change of a magnet linear scale, a magnet rotor, or the like, and detecting a displacement incrementally. Another object is to appropriately set the magnitude of the bias magnetic field so that an appropriate detection magnetic field range can be obtained. Another object is to change the magnitude of the bias magnetic field so that the sensitivity can be set to an arbitrary value or the sensitivity can be changed. Another object is to realize a highly sensitive magnetic field detection device having a simple structure and a low detection threshold. or,
Another object of the invention is to perform detection with low power consumption. These objects are objects individually achieved by each of the inventions disclosed in the present application, and it is not to be understood that the present invention achieves all of these objects.

[0005]

According to the first aspect of the present invention, as the magnitude of the external magnetic field, which is a component in the direction of the detection axis, increases, the impedance increases and passes the maximum value. Then, in a magnetic field detection device using the magneto-impedance effect in which the impedance changes with a decreasing magnetic impedance characteristic, a magneto-sensitive element that is excited in a circular direction by a pulse current or a high-frequency current and changes in impedance in accordance with an external magnetic field, Oscillating means for supplying a pulse current or an alternating current to the magnetic element, and detecting means for detecting a physical quantity related to the impedance between the terminals of the magnetic sensing element,
Bias means for applying a bias magnetic field to the magneto-sensitive element, and an output signal of the detection means at a predetermined level in order to set a region where the impedance decreases as the magnitude of the external magnetic field in the magnetic impedance characteristic increases as a measurement region. And comparing means for outputting a comparison result as a binary signal.

The present magnetic field detecting device is a device for detecting whether an external magnetic field in a detection axis direction is larger or smaller than a predetermined level. The magneto-sensitive element is, for example, a linear element as shown in FIG. 2, and is an element that is excited in a circumferential direction by flowing a pulse current I or an alternating current I. Due to the circumferential excitation _Hr , the internal magnetic moment M changes according to the pulse current or the alternating current. Then, it will vary by the presence of a magnetic field H _x change characteristic of the magnetic moment M is applied. That is, due to the change in the characteristics, the magnetic permeability of the magneto-sensitive element changes due to the magnetic field. Since both the skin resistance component and the inductance component of the magnetic sensing element are proportional to the square root of the magnetic permeability μ, the impedance Z is proportional to the square root of the magnetic permeability. As a result, the impedance Z of the magneto-sensitive element changes due to the magnetic field. By measuring the magnitude of this impedance Z, the detection axis x
It is possible to measure the direction of the magnetic field H _x. The present invention is based on such a principle.

[0007] The magnetic impedance characteristic is a change characteristic of the impedance with respect to the magnetic field H _x the applied the sensitive element having such a magnetic impedance effect Z (absolute value) is as shown in FIG. The magnetic impedance since it does not depend on the direction of the magnetic field H _x, + detection axis direction (+ x) and - out with the detection axis direction (-x), the change characteristic of the impedance Z becomes symmetrical. Then, as the absolute value of the magnetic field H _x is increased, the impedance Z increases and exceeds the maximum value A, B, decreases. In terms of magnetic impedance characteristics, the regions used by the present invention are regions W1 and W2 that exceed the magnetic field giving the maximum value A or B. In order to make this area a use area, a bias magnetic field H ₀ or −H ₀ is applied to the magneto-sensitive element. For simplicity, consider only region W1. In this state, when an external magnetic field ΔH _{x in the} detection axis direction to be detected is applied, the magnetic field component in the detection axis direction of the magneto-sensitive element becomes H ₀ + ΔH _x , and the external magnetic field −ΔH _{x in the} detection axis direction to be detected. Is applied, the magnetic field component of the magneto-sensitive element in the detection axis direction becomes H ₀ −ΔH _x . Impedance Z ₀ -? Z ₁ is detected to the magnetic field component H ₀ + ΔH _x, the impedance Z ₀ + ΔZ ₂ is detected for the magnetic field component H ₀ - [Delta] H _x. Displacement Δ of impedance with respect to impedance Z ₀ corresponding to bias magnetic field H ₀
By measuring Z, the corresponding external magnetic field ΔH _x can be measured.

[0008] A physical quantity related to the impedance between the terminals of the magneto-sensitive element is detected by the detecting means, and the physical quantity is detected by the comparing means.
An output signal of the detection means is compared with a predetermined level, and a comparison result is output from the comparison means. The oscillating means for supplying a pulse current or an alternating current to the magneto-sensitive element may be a constant current source, a constant voltage source, or not. The physical quantity detected by the detecting means is arbitrary as long as it changes in relation to the impedance between the terminals of the magneto-sensitive element. For example, if a constant current is supplied to the magneto-sensitive element from the oscillating means, the detecting means may detect the voltage between the terminals of the magneto-sensitive element. Conversely, if a constant voltage is supplied to the magneto-sensitive element from the oscillating means, the detecting means may detect the current flowing between the terminals of the magneto-sensitive element. When neither the constant current source nor the constant voltage source is used, the current I flowing between the terminals of the magneto-sensitive element and the voltage V between the terminals are detected, and the impedance of the magneto-sensitive element is determined from the ratio V / I. What is necessary is just to detect.

In the above magnetic impedance characteristics, generally, | ΔZ ₁ | ≠ | ΔZ
₂ |. However, since the present invention determines whether or not the impedance is large with respect to the predetermined impedance, the non-linearity of the measurement does not particularly matter.

Since the present invention uses such a principle, the slope of the curve of the magnetic impedance characteristic can be appropriately selected by appropriately selecting the magnitude of the bias magnetic field. In other words, the sensitivity can be appropriately set according to the detection target of the magnetic field without using the negative feedback circuit. Further, in one detecting device, the sensitivity can be changed by changing the magnitude of the bias magnetic field. Therefore, it is possible to appropriately set the sensitivity in the relationship between the measurement environment and the magnitude of the magnetic field to be detected. For example, in an environment where the noise magnetic field is small,
The bias magnetic field may be adjusted to increase the sensitivity, and in an environment with a large noise magnetic field, the bias magnetic field may be adjusted to reduce the sensitivity. This bias magnetic field can be varied by adjusting the magnitude of the current flowing through the coil that generates the bias magnetic field.

The magneto-sensitive element desirably has a magnetic anisotropy that is easily magnetized in the circumferential direction. As a result, the change in the magnetic impedance due to the external magnetic field is large, and the detection sensitivity can be improved. One such material is an amorphous magnetic material. Desirably, a linear magnetic body is good. As described above, the present invention can detect a magnetic field with high sensitivity, detect a magnetic field change of a magnet linear scale, a magnet rotor, or the like with high sensitivity, and output a magnetic field change with a pulse. It can be used.

Since the pulse current contains a high-frequency component, it is also included in a kind of high-frequency current. or,
The pulse current or the high-frequency current may be, for example, applied for only one cycle or a periodic signal applied repeatedly.

According to a second aspect of the present invention, as the magnitude of the external magnetic field, which is a component in the direction of the detection axis, increases, the impedance increases. In a magnetic field detection device using a magnetic impedance effect, a pair of magneto-sensitive elements, which are excited in a circulating direction by a pulse current or a high-frequency current and whose impedance changes according to an external magnetic field,
An oscillating means for supplying a pulse current or an alternating current to the pair of magneto-sensitive elements, a pair of detecting means for respectively detecting a physical quantity related to an impedance between terminals of the pair of magneto-sensitive elements,
A means for applying a bias magnetic field to the magneto-sensitive element in order to set the area where the impedance decreases as the magnitude of the external magnetic field in the magnetic impedance characteristic increases as the measurement area, and the magnitude of the external magnetic field increases. And a pair of bias means for applying a bias magnetic field to the pair of magneto-sensitive elements so that the internal magnetic field of the pair of magneto-sensitive elements increases and the other decreases. And a comparison means for comparing the output signal of the difference output means with a predetermined level and outputting a comparison result as a binary signal.

According to the present invention, there is provided a magnetic sensing device according to the first aspect.
It is provided with a pair of elements. Inspection through a pair of magneto-sensitive elements
If the magnetic field to be emitted is common, the region in FIG.
Magnetic sensing element operating in W1 and magnetic sensing element operating in region W2
And a pair of children. That is, one of the magneto-sensitive elements
Internal magnetic field is H₀+ ΔH_x(Point C in FIG. 3),
The internal magnetic field of the magneto-sensitive element is -H₀+ ΔH_x(D in FIG. 3
(Point) is applied. Common detection
Magnetic field to be ΔH_xDirection of the bias magnetic field with respect to the direction of
Are applied in directions opposite to each other. Do this
And one detecting means is Z₀−ΔZ₁The Impedance
(Point C), and the other detecting means₀+ ΔZ_Two
Is detected (point D). The difference output means
The difference between the output signals of the pair of detection means is calculated.
-ΔZ₁−ΔZ _TwoShould be detected from
Magnetic field ΔH_xWill be measured. Do this
Thus, common-mode noise is removed. Also, to temperature
On the other hand, the magnetic impedance characteristic of FIG.
Because the size of the dance is translated,
Temperature compensation is possible by adopting the differential configuration of
Becomes

When the directions of the magnetic fields to be detected passing through the pair of magneto-sensitive elements are opposite to each other, that is, the magnetic field ΔH _x passes through one of the magneto-sensitive elements, and the magnetic field −H passes through the other magneto-sensitive element. ΔH
_{When x} is penetrated, the bias magnetic field is applied in the same direction in a pair of magneto-sensitive elements. That is, the internal magnetic field of one of the magneto-sensitive elements in the region W1 of FIG.
When H ₀ + ΔH _x (point C), the internal magnetic field of the other magneto-sensitive element becomes H ₀ −ΔH _x (E
Point). Also in this case, in the same manner as described above, one detecting means detects the impedance (point C) of Z ₀ −ΔZ ₁ , and the other detecting means detects Z ₀ + ΔZ ₂
Is detected (point E). The difference output means
The difference between the output signals of the pair of detection means is calculated, and the magnetic field ΔH _x to be detected is measured from the output −ΔZ ₁ −ΔZ ₂ . By doing so, common mode noise is removed, and drift countermeasures and temperature compensation can be performed.

According to the present invention, the input signal to the comparing means does not include a signal corresponding to the bias magnetic field H ₀ . Therefore, the setting of the predetermined level in the comparing means is:
Minimum ～DerutaH _x ranges to be detected external magnetic field (- [Delta] H _x
(Maximum value) can be set in the range, so that the level setting is simplified. If zero a predetermined level, to detect the timing at which the direction of the magnetic field is changed, the minimum value of - [Delta] H _x, or be set to a level corresponding to the maximum value of [Delta] H _x, minimum or maximum value of the magnetic field ( (Extreme value of the magnetic pole) can be detected.

The oscillating device may be one that supplies a pulse current or an alternating current to a pair of magneto-sensitive elements in common, or one that supplies them independently and separately. If they are shared, the manufacturing cost is reduced and the size of the device can be reduced.

According to a third aspect of the present invention, the comparing means includes an input signal
A first comparing means for comparing the input signal with a first predetermined level;
With a second predetermined level, and a second comparing means for comparing
The output signals of the first comparison means and the second comparison means are
It is characterized by including orientation information. Structure of the invention of claim 1
According to the description, as described above, the magnetic field to be detected + ΔH_x
, The impedance Z₀−ΔZ₁Value according to
Magnetic field to be output and detected-ΔH_xFor Z₀+ ΔZ
_TwoIs detected. Therefore, two predetermined levels
Is provided, the minimum value and the maximum value of the magnetic field, that is, the magnetic pole
Detection near the peak becomes possible. This allows the direction of the magnetic field
Can be detected. The invention of claim 2
According to the configuration, as described above, the magnetic field to be detected + ΔH
_xWith respect to the impedance −ΔZ₁−ΔZ_TwoAccording to
Value is detected and the magnetic field to be detected-ΔH_xFor + Δ
Z₁+ ΔZ_TwoIs detected. Therefore, two
By providing a predetermined level, the minimum and maximum values of the magnetic field,
That is, detection near the peak of the magnetic pole becomes possible. This
Thus, the direction of the magnetic field can be detected.

According to a fourth aspect of the present invention, the oscillating means supplies a pulse current to the magneto-sensitive element, is provided between the magneto-sensitive element and the detecting means, and appears on the magneto-sensitive element in synchronization with the pulse current. A switch for passing only the first pulse. With this configuration, the first pulse synchronized with the pulse current can be used as the detected value of the magnetic field component. In magnetic field detection using the above principle, the peak value of the first pulse of the detection signal is proportional to the external magnetic field. Therefore, by adopting this configuration, it is possible to perform highly accurate detection without being affected by noise.

According to a fifth aspect of the present invention, the detecting means has a signal processing circuit for outputting a signal formed by a peak value of the input signal or a peak value repeatedly input or a value related to the amplitude of the AC signal. And The peak value of the signal detected from the magneto-sensitive element is proportional to the external magnetic field to be detected. Therefore, for example, when the peak value is held or when a pulse current is supplied repeatedly, a signal (envelope signal, integral signal, low-pass filtered signal, Signal, etc.) can be used as the detected value of the magnetic field. When an alternating current is supplied, an amount (envelope signal, integral signal,
Low-pass filtered signal, smoothed signal, etc.)
Ask for. The external magnetic field may be a DC magnetic field or an AC magnetic field. In the case of an AC magnetic field, an AC magnetic field having a frequency sufficiently lower than the repetition frequency of the pulse current is measured.
That is, the AC magnetic field can be continuously measured macroscopically.

The invention according to claim 6 is characterized in that the detecting means is a peak hold circuit or an integrating circuit.
With this configuration, since the high-frequency noise component is removed, a magnetic field change that changes at a frequency lower than the frequency of the pulse current or the alternating current applied to the magneto-sensitive element can be detected with high accuracy.

The invention according to claim 7 is characterized in that the bias means is an electromagnet for passing a direct current through the coil or a permanent magnet. The sensitivity can be easily changed by using an electromagnet as the bias means. The sensitivity of the permanent magnet can be set to an appropriate value according to the measurement environment by appropriately setting the magnitude of the magnetic force.
When a permanent magnet is used, power saving can be achieved.

According to an eighth aspect of the present invention, there is provided a negative feedback excitation coil which is wound in the circumferential direction of the magneto-sensitive element and generates a magnetic field for canceling an external magnetic field which is a component in a detection axis direction in accordance with an output signal of the detection means. It is characterized by having. This allows
The point where the bias magnetic field is applied on the magnetic impedance characteristic curve can always be operated as the operating point. This makes it possible to detect an external magnetic field with good linearity and stability.

According to a ninth aspect of the present invention, the negative feedback exciting coil comprises:
It is characterized in that it also serves as a bias means. As a result, highly accurate magnetic field detection with good linearity can be performed without complicating the structure. A tenth aspect of the present invention is characterized by comprising a rectangular wave oscillating circuit and a differentiating circuit for differentiating a rectangular wave output from the rectangular wave oscillating circuit and using a differentiated signal as the pulse current. With this configuration, it is possible to realize high sensitivity and low power consumption.

According to an eleventh aspect of the present invention, the magneto-sensitive element has magnetic anisotropy in a circumferential direction. By having magnetic anisotropy in the circling direction, it is possible to improve the detection sensitivity of the external magnetic field.

According to a twelfth aspect of the present invention, the magneto-sensitive element is an element that generates a skin effect with respect to a pulse current or an alternating current. By generating the skin effect, the current is constrained to the surface, so that the change in magnetic impedance can be increased by a pulse current or an alternating current due to an external magnetic field, and the detection sensitivity can be improved.

According to a thirteenth aspect of the present invention, the magneto-sensitive element is made of an amorphous magnetic material. With this configuration, it is possible to increase the magnetic anisotropy such that the magnetic permeability in the circumferential direction is larger than the magnetic permeability in the axial direction.

The invention according to claim 14 is characterized in that the magneto-sensitive element is a wire made of an amorphous magnetic material.
With this configuration, it is possible to increase the magnetic anisotropy such that the magnetic permeability in the circumferential direction is larger than the magnetic permeability in the axial direction.

According to a fifteenth aspect of the present invention, the magneto-sensitive element is supported and energized at both ends by electrodes formed on the substrate, and includes the space between the substrate and the magneto-sensitive element, and the periphery of the magneto-sensitive element is covered with a gel-like substance. It is characterized by being done. The gel material can prevent the magneto-sensitive element from being subjected to external strain. In particular, in the case of an amorphous magnetic material, a reduction in detection accuracy due to distortion is a problem. However, by covering the periphery with a gel-like material in this way, it is possible to prevent the distortion from affecting the magneto-sensitive element.
In particular, in the case of resin molding, the stress generated in the process of cooling the resin is applied to the magneto-sensitive element, but the gel-like substance absorbs this distortion, thereby preventing the magneto-sensitive element from being stressed. be able to. The gel-like substance means a sol solidified in a jelly state. For example, gels such as silicone gels, silica gels, elastomers, and gelatins, and generally gels such as hydrogels, lyogels, and elastic gels can be used. In short, any substance that absorbs elasticity may be used.

According to a sixteenth aspect of the present invention, the magneto-sensitive element is placed on electrodes that are supported and energized at both ends, and aluminum or an aluminum alloy is covered from above on the magneto-sensitive element, and ultrasonic bonding is performed. It is characterized by joining with an electrode. If the magneto-sensitive element is made of an amorphous magnetic material, crystallization occurs when heated, so that heat bonding cannot be performed.
Weak to distortion. Therefore, it is desirable to join the magneto-sensitive element to the electrode by ultrasonic bonding. When ultrasonic bonding is performed, aluminum or an aluminum alloy is placed on the magneto-sensitive element, and the aluminum or aluminum alloy is buffered by applying pressure using an ultrasonic tool, and strain is applied to the magneto-sensitive element. Is prevented. Also, the oxide film formed on the surface of the magneto-sensitive element is peeled off by ultrasonic waves and taken into aluminum or an aluminum alloy. As a result, good mechanical and electrical bonding between the aluminum or aluminum alloy and the magneto-sensitive element is achieved.

According to a seventeenth aspect, the electrode is nickel,
It is characterized by being made of aluminum, gold, copper, silver, tin, zinc, platinum, magnesium, rhodium, or an alloy containing at least one of these. By using these materials for the electrodes, it is possible to perform strong bonding by ultrasonic bonding with the magneto-sensitive element.

The invention according to claim 18 is characterized in that the electrode has a layer made of aminium or an aluminum alloy as a surface layer. With this configuration, the joining property with the aminium or aluminum alloy placed on the magneto-sensitive element is good, and the magneto-sensitive element can be firmly joined to the electrode.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments. Note that the present invention is not limited to the embodiments described below. First Embodiment The specific configuration of the magnetic field detection device is as shown in FIG. The magneto-sensitive element 10 is made of, for example, a linear zero magnetostrictive amorphous magnetic material. In particular, an amorphous wire linearly extending in the detection axis direction is used. As the amorphous magnetic material, for example, a magnetic material such as CoSiB-based, FeCoSiB-based, or FeSiB-based alloy can be used. The specific dimensions are 3 mm in length and 30 μm in diameter. Magnetic sensing element 1
A bias magnetic field is applied to 0 by the thin film magnet 20 as a bias means. With this thin film magnet 20, a bias magnetic field H ₀ on the magnetic impedance characteristic curve shown in FIG. 1 is obtained. The oscillator 13 oscillates a rectangular wave. As the oscillator 13, more specifically, a C-MOS multivibrator can be used. This square wave is differentiated by the differentiating circuit 14, sense via the resistor R ₄ magnetosensitive 1
0 is applied. Resistor R ₄ is a resistor for supplying a constant current. The pulse current I is supplied to the magneto-sensitive element 10 by such a circuit. The rise time of the pulse current is, for example, about 5 ns. The oscillator 13 and the differentiating circuit 14 constitute an oscillating means.

One end of the magneto-sensitive element 10 is connected to the switch 15. More specifically, for example, an analog switch including a transistor can be used as the switch 15. Next, the signal that has passed through the switch 15 is input to the signal processing circuit 16. This signal processing circuit 1
6 can be as an example, constituted by a peak-hold circuit composed of the capacitor C ₄ resistors R ₅ Prefecture. The peak of the pulse signal repeatedly detected by the signal processing circuit 16 is held. When repeatedly supplying a pulse current and repeatedly detecting a pulse signal, in addition to the peak hold circuit, if an amount proportional to the peak is detected, an integrating circuit, a smoothing circuit, or the like may be used. It is possible.

The magnetic sensing element 10 and the wiring leading to the magnetic sensing element 10 have inductance and stray capacitance, and other lines have inductance and stray capacitance. Therefore, the voltage between the terminals of the magneto-sensitive element 10 includes not only a single pulse responding to the pulse current but also a subsequent vibration waveform. For this reason, a switch 15 is provided to extract only a component that responds to the pulse current. In order to achieve phase synchronization between the peak timing of the voltage between the terminals of the magneto-sensitive element 10 and the timing when the switch 15 is completely turned on, a pulse supplied to the magneto-sensitive element 10 in response to the control signal of the switch 15 Current I is about 10 ns
Have been delayed. In short, a control signal may be applied to the switch 15 so as to be turned on only in a period in response to the pulse current and passing only a signal component that is accurately proportional to the external magnetic field. The switch means 15 and the signal output circuit 16 constitute a detection means.

The output signal from the signal processing circuit 16 is
7 is input. The signal terminal of the signal processing circuit 16 is connected to the non-inverting input terminal of the comparator 171, and the inverting input terminal of the comparator 171 is applied with a voltage divided by the resistors R ₆ and R ₇ as a predetermined level. Then, the output signal of the comparator 171 constituting the comparing means is output as a binary signal. This output signal is a signal in which the magnitude of the magnetic field to be detected is determined in a binary manner.

With the above configuration, the impedance between the terminals of the magneto-sensitive element 10 is detected as the voltage between the terminals of the magneto-sensitive element 10. The signal output from the signal processing circuit 16 becomes a value related to the impedance between the terminals of the magneto-sensitive element, and this value is compared with a predetermined level by the comparator 171. Thus, it is detected whether the magnetic field to be detected is larger than a predetermined level. Thus, in this embodiment, shown in FIG. 1, the magnetic impedance characteristic curve, the bias magnetic field H ₀ to operate in a region W1 to take impedance is reduced to the magnetic field is increased is set. As a result, by changing the bias magnetic field,
The sensitivity can be changed according to the use environment. or,
By appropriately selecting the bias magnetic field, it is possible to make the sensitivity optimal for the use environment.

Input to the inverting input terminal of the comparator 171
The applied voltage is a predetermined level that is a reference
The bell is giving. This predetermined level corresponds to H in FIG.
₀-ΔH_xFrom the minimum value of₀+ ΔH_xRange of maximum values of
It can be set to any level within. In particular, the external magnetic field Δ
H_xIs zero and the bias magnetic field H₀Only when is detected
Then, the voltage between the two input terminals of the comparator 171 becomes zero.
If the predetermined level is set so that the external magnetic field ΔH_xof
The orientation can be determined. Further, the signal processing circuit 1
Two comparators that judge the level of the output of 6
The predetermined level of one comparator is H₀From
H₀+ ΔH_xSet to any level within the maximum value range of
The predetermined level of the comparator is H₀-ΔH _xMinimum of
H from the value₀The magnetic field can be set at any level in the range
In the vicinity of the peak. That is, N
It becomes possible to detect the vicinity of the peak of the pole and the S pole.

Second Embodiment Next, a description will be given of a detection apparatus in which detection accuracy is further improved by removing in-phase noise and the like by using a pair of a magneto-sensitive element and detection means. As shown in FIG.
The connection point d between 0a and 10b is connected to the ground,
A pulse current is supplied from the other ends e and f. As in the previous embodiment, the thin film magnet 20a serving as the bias means is provided.
20b, the bias magnetic fields + H ₀ and −H ₀ shown in FIG. 3 are applied to the magneto-sensitive elements 10a and 10b, respectively.
Has been given. That is, the bias magnetic field is applied so that the magneto-sensitive element 10a operates in the area W1 of FIG. 3 and the magneto-sensitive element 10b operates in the area W2 of FIG. The magnetic field ΔH _x to be detected passes through the pair of magneto-sensitive elements 10a and 10b in the same direction in the positive direction of the current, but the bias magnetic fields are opposite to each other.

The terminal e on the active side of the magneto-sensitive element 10a
Is connected to a switch 15a, and the terminal f on the live line side of the magneto-sensitive element 10b is connected to the switch 15b.
The switch 15a is connected to a signal processing circuit 16a including a peak hold circuit, and the switch 15b is connected to a signal processing circuit 16a.
A similar signal processing circuit 16b is connected.

The output signal Ga ₁ of the signal processing circuit 16 a is input to the inverting input terminal of the differential amplifier 21.
Of the signal processing circuit 16b.
b ₁ is entered. Therefore, the differential amplifier 21 has G
b ₁ -Ga ₁ = Eb ₁ -Ea ₁ is input. However, Ea ₁ is the voltage to ground of the terminal e of the hot-side of the magneto-sensitive element 10a, Eb ₁ is the voltage to ground of the hot-side terminal f of the magnetic sensing element 10b. Voltage Ea _1, the impedance Z ₀
The voltage Eb ₁ is proportional to −ΔZ ₁ and the voltage Eb ₁ is the impedance Z ₀ +
It is proportional to ΔZ ₂ . Therefore, the output voltage of the differential amplifier 21 has an impedance Δ proportional to the magnetic field ΔH _x to be detected.
It is proportional to Z ₁ + ΔZ ₂ . Therefore, it is possible to detect the external magnetic field [Delta] H _x from the output voltage. ΔZ ₁ and Δ
Assuming that Z ₂ is equal, twice the sensitivity can be obtained as compared with the previous embodiment. By inputting the output voltage of the differential amplifier 21 to the comparator 171, it can be determined whether the magnetic field ΔH _x to be detected is larger than a predetermined level.

In the circuit configuration shown in FIG.
1 includes a bias magnetic field H ₀Contains the signal
Absent. Therefore, the inverting input terminal of the comparator 171 is marked.
The applied voltage becomes a predetermined level for magnetic field level judgment.
You. This predetermined level is -ΔH in FIG._xMinimum value of
From + ΔH_xSet to any level within the maximum value of
Just do it. In particular, if the predetermined level is set to zero, the external magnetic field
ΔH_xCan be determined. In addition, differential
Comparator that determines the level of the output of the width unit 21
Are provided, and the predetermined level of one comparator is 0
From + ΔH_xSet to any level within the maximum value range of
The predetermined level of the comparator is -ΔH_xIs the minimum of
To an arbitrary level in the range of
It is possible to detect the vicinity of the loop. That is, N pole, S pole
In the vicinity of the peak. in this way
In the present embodiment, a predetermined level for determining the magnitude of the magnetic field is used.
Does not include a component corresponding to the bias magnetic field.
Therefore, the predetermined level can be set independently of the bias magnetic field.
Therefore, it is easy to set the predetermined level.

As another example using a pair of magneto-sensitive elements, the configuration shown in FIGS. 6 and 7 can be employed. That is, the present embodiment is an apparatus for detecting the reversal timing of the magnetic pole of the magnetic scale as shown in FIG. The magneto-sensitive element 10a and the magneto-sensitive element 10b are provided at a phase difference of 180 degrees in magnetic field phase. Therefore, the directions of the magnetic field ΔH _x passing through the magneto-sensitive element 10a and the magneto-sensitive element 10b are opposite to each other with respect to the positive direction of the current. The bias magnetic field H ₀ is applied to the magneto-sensitive elements 10a and 10b in the same direction with respect to the positive direction of the current. Region W on the magnetic impedance characteristic curve of FIG.
1 operates two magnetic sensing elements. Therefore,
Each sensitive element 10a, 10b of the terminal voltage E _a, E _b, respectively, as in FIG. 7 (b), (c) , changes. That is, the phases are different by 180 degrees. The difference voltage changes as shown in FIG. 7D, and by using the two comparators 171a and 171b shown in FIG. 6, the timing at which the peaks near the N pole and the S pole pass from each output. Can be detected.

Third Embodiment Next, the internal magnetic field of the magneto-sensitive element 10 is always set to the bias magnetic field H.
An embodiment in which a negative feedback control is performed so as to be ₀ and a magnetic field is detected will be described. FIG. 8 shows the configuration of the device. The difference from the example shown in FIG. 4 is that a negative feedback excitation coil 12 for applying a negative feedback magnetic field to the magneto-sensitive element 10 is provided. In the present embodiment, the negative feedback exciting coil 12 also constitutes a bias means. That is, the thin film magnet 20 used in the above-described embodiment is not used, and the bias magnetic field is applied by the negative feedback excitation coil 12.

In this embodiment, the output of the signal processing circuit 16 is amplified by the differential amplifier 22, and the output signal is applied to the negative feedback excitation coil 12. When the external magnetic field ΔH _X is zero, the voltage at the inverting input terminal of the differential amplifier 22 is set so that only the bias magnetic field H ₀ flows through the negative feedback excitation coil 12 so as to be applied to the magneto-sensitive element 10. Are adjusted by resistors. For example, when the external magnetic field ΔH _X is zero, it is assumed that a current is supplied from the output of the differential amplifier 22 to the ground of the negative feedback excitation coil 12 and a bias magnetic field H ₀ is generated. Next, when the external magnetic field ΔH _X increases in the positive direction, the impedance between the terminals of the magneto-sensitive element 10 decreases, and as a result, the voltage between the terminals also decreases. Then, the voltage of the non-inverting input terminal of the differential amplifier 22 decreases, and the current flowing through the negative feedback excitation coil 12 decreases. As a result, the bias magnetic field H ₀ decreases, and this decrease compensates for the increase in the external magnetic field ΔH _X , and the negative feedback control is performed so that the internal magnetic field of the magneto-sensitive element 10 becomes a constant bias magnetic field H _0. Have been.

Similarly, when the external magnetic field −ΔH _x increases in the negative direction, the impedance between the terminals of the magneto-sensitive element 10 increases, and the voltage between the terminals also increases. Therefore, the voltage at the non-inverting input terminal of the differential amplifier 22 increases, and the negative feedback excitation coil 12
The current flowing in the direction of the ground increases. As a result, the bias magnetic field is increased, and this increase compensates for the decrease in the external magnetic field. As described above, since the negative feedback is applied so that the two input voltage differences of the differential amplifier 22 become zero, no matter how the external magnetic field to be detected fluctuates, the internal magnetic field of the magneto-sensitive element 10 is Constant bias magnetic field H
Controlled to ₀ . As a result, since the operating point on the magnetic impedance characteristic curve of FIG. 1 always becomes a bias magnetic field,
It is possible to detect a magnetic field having good linearity. Differential amplifier 22
Is determined by the comparator 171.
The magnitude of the detected magnetic field can be determined. Comparator 1
The method of setting the predetermined level at 71 and the comparison result are the same as in the first embodiment shown in FIG.

In this embodiment, the bias magnetic field H ₀ can be adjusted by adjusting the voltage level of the inverting input terminal of the differential amplifier 22.

In this embodiment, the negative feedback excitation coil 1
2, the bias means is also used, but a bias means such as a permanent magnet or an electromagnet may be used separately from the negative feedback excitation coil.

Fourth Embodiment FIG. 9 shows an example using a pair of magneto-sensitive elements. This corresponds to the embodiment shown in FIG. However, in the circuit of FIG. 5, the terminals of the two inputs to the differential amplifier 21 are inverted. That is, the output of the signal processing circuit 16a is input to the non-inverting input terminal, and the output of the signal processing circuit 16a is input to the inverting input terminal. Also in this case, the pair of negative feedback excitation coils 1
2a, by passing a negative feedback current to 12b, offset the external magnetic field, the internal magnetic field of the pair of magneto-sensitive element is always it is possible to bias field H _0. By resolution of the output of the differential amplifier 21 and the resistor R ₁₀ and the resistor R _11, and applies a predetermined level that corresponds to the bias field H ₀ to the output of the differential amplifier 21. When the external magnetic field ΔH _x to be detected is zero, the output of the differential amplifier 21 is zero.

When the external magnetic field −ΔH _{x in the} −x-axis direction is applied to the magneto-sensitive elements 10a and 10b, the output of the differential amplifier 21 becomes positive. When the output of the differential amplifier 21 becomes positive, the current supplied to the negative feedback excitation coils 21a and 21b increases.
This makes it possible to bias field is increased to compensate for the decrease in the magnetic field by the external magnetic field - [Delta] H _x. Conversely, + x
When the external magnetic field [Delta] H _x axial magneto-sensitive element 10a, is applied to 10b, the output of the differential amplifier 21 becomes negative. When the output of the differential amplifier 21 becomes negative, the negative feedback excitation coil 21
a, the current flowing to 21b is reduced. This makes it possible to bias field is reduced to compensate for the increase in the magnetic field by the external magnetic field [Delta] H _x. In this manner, eventually, current flows through the negative feedback excitation coils 21a and 21b so that the two input differences of the differential amplifier 21 become zero, so that the internal magnetic field of the magnetosensitive elements 10a and 10b becomes , Regardless of the direction and magnitude of the external magnetic field ΔH _x to be detected, the bias magnetic field H ₀ is always obtained. This makes it possible to determine the level of the magnetic field with the operating point fixed.

The configuration for setting the predetermined level in the comparator 171 and for detecting the vicinity of the magnetic field peaks of the N pole and the S pole using the two comparators are the same as those in the above-described embodiment.

Other Embodiments In the above embodiment, the first pulse of the voltage generated between the terminals is synchronously detected by a switch in synchronization with the pulse current applied to the magneto-sensitive element, and the peak is held. . But,
As shown in FIG. 10, the external magnetic field may be detected by using smoothing or integration by rectification of the diode 41. In the above embodiment, a pulse current is applied. However, in the apparatus shown in FIG. 10, an alternating current may be supplied to the magneto-sensitive element.

FIG. 11 shows an example of an apparatus in which the present invention is applied to detecting a magnetic pole fluctuation of a magnet rotor. Thus, the pulses are serially output in synchronization with the rotation of the magnet rotor, and counting the serial pulses makes it possible to measure the rotation angle. In FIG. 11, the output pulse is transmitted by the FM modulator, and the number of pulses is counted by the receiving device, whereby the rotation angle can be detected. Of course, the pulses may be counted on the transmitting side, and the counted value may be transmitted by the FM modulator. In this embodiment, an integration circuit including a resistor and a capacitor is used as a signal processing circuit of the detection unit. Further, the change of the magnetic pole of the magnet linear scale may be detected by the magnetic field detecting device of the present invention. With these configurations, a highly sensitive incremental displacement detector can be realized. Alternatively, as shown in FIG. 12, a bias magnetic field may be generated by applying the output of the oscillation circuit to the coil 25. Power saving can be achieved.

FIG. 13 shows an example in which the magnetic sensing element is magnetically shielded with a permalloy 40 or the like when the use environment has a large noise magnetic field. This makes it possible to detect a magnetic field to be detected with high accuracy without being affected by noise.

Next, the mechanical configuration of the magnetic field detecting device will be described.
As shown in FIG. 14, the magneto-sensitive element 10 is arranged on the substrate 30. Electrodes 31 and 32 are provided on the substrate 30, and the magneto-sensitive element 10 is provided thereon such that both ends are supported and energized. The magneto-sensitive element 10 is bonded to the electrodes 31 and 32 by ultrasonic bonding using aluminum 33 and 34. Also, substrate 3
A thin film magnet 20 serving as a bias means is formed on the back surface of the zero.

Hereinafter, the individual element 100 as shown in FIG.
The method for forming is described in detail. First, copper is vapor-deposited on the surface of a substrate made of any one of flat ceramics, PCB resin, silicon and the like. The substrate is preferably insulating,
At least the electrode forming portion needs to be insulated. Then, the electrodes 31, 32 are subjected to a photoreflection process.
Is etched so as to leave. In this way, a substrate on which a number of magneto-sensitive elements 10 can be arranged is obtained. Next, the magneto-sensitive element 10 is arranged on the electrodes 31 and 32 on the substrate, and as shown in FIG. 15, a plate 33 made of aluminum or an aluminum alloy is arranged thereon, and the bonding tool 90 is used from above. By applying pressure, ultrasonic vibrations are generated to join. At this time, the plate 33 and the magnetic sensing element 1
0 and the electrodes 31 are connected to each other. afterwards,
By cutting the plate 33, the joining of the magneto-sensitive element 10 to one electrode is completed. As described above, a large number of magneto-sensitive elements are sequentially arranged on one substrate to perform ultrasonic bonding. Next, the substrate is separated into strips as shown in FIG.

The material of the electrode 31 is not limited as long as it is a material which can be ultrasonically bonded to the magneto-sensitive element 10 and has conductivity. For example, nickel, aluminum, gold, copper, silver, tin, zinc,
Platinum, magnesium, rhodium, or an alloy containing at least one of these is desirable. As shown in FIG. 15, a layer 311 made of aluminum or an aluminum alloy may be formed on the surface of the electrode 31. The formation of this layer is performed by placing an aluminum or aluminum alloy plate on the electrode 31, placing the magneto-sensitive element 10 thereon, further placing a plate 33 made of aluminum or aluminum alloy, and performing ultrasonic bonding. Can be formed. That is, when the material sandwiching the magneto-sensitive element 10 from above and below is aluminum or an aluminum alloy, mechanical joining and electrical contact can be completed. Further, the bonding may be performed after aluminum or an aluminum alloy is deposited or plated on the electrode 31. The electrodes 31 and 32 serve as lands for wire bonding for electrical connection to a wiring film and lead pins (not shown).

The reason why ultrasonic bonding is used is that since an amorphous magnetic material, particularly an amorphous wire, is used as a magneto-sensitive element, solder bonding by heating is difficult.
This is because it cannot be used because crystallization occurs. Further, the surface of the amorphous magnetic material is oxidized, so that solder bonding cannot be performed. The present inventors have found for the first time that the use of aluminum or an aluminum alloy as a solder for ultrasonic bonding results in a strong mechanical bond and good electrical contact. The surface oxide film of the amorphous wire is peeled off by the ultrasonic vibration, is combined with aluminum as a reducing element, and is easily taken into the aluminum plate. It is believed that this mechanism improves electrical contact and mechanical bonding. By providing the plate 33 made of aluminum or its alloy on the magneto-sensitive element 10 made of amorphous wire, the bonding tool 90
Is prevented from being transmitted directly to the magneto-sensitive element 10. That is, the plate 33 acts as a buffer, and prevents the magneto-sensitive element 10a from generating stress distortion during ultrasonic bonding.

Next, in the individual element 100 shown in FIG. 14, the periphery of the magneto-sensitive element 10 is covered with the gel material 35. That is, between the magneto-sensitive element 10 and the substrate 30 and between the magneto-sensitive element 1
0 is covered with a gel-like substance. The reason for covering the magneto-sensitive element 10 with this gel-like substance is that no stress is applied to the magneto-sensitive element 10 so that no stress is generated inside the magneto-sensitive element 10. Since the magneto-sensitive element 10 is made of an amorphous wire, its magnetic properties are easily affected by distortion. This stress is generated by shrinkage when the resin is cured during molding. This stress is absorbed by the gel material 35 and is not applied to the magneto-sensitive element 10. By doing so, detection accuracy can be improved. Although the silicone gel is used for the gel material 35, an elastic gel such as silica gel, elastomer, gelatin or the like can be used.

[Brief description of the drawings]

FIG. 1 is a characteristic diagram showing the principle of the present invention.

FIG. 2 is an explanatory diagram illustrating the principle of the present invention.

FIG. 3 is a characteristic diagram showing the principle of the present invention.

FIG. 4 is a circuit diagram of a magnetic field detection device according to the first embodiment of the present invention.

FIG. 5 is a circuit diagram of a compensation type magnetic field detection device according to a second embodiment of the present invention.

FIG. 6 is a circuit diagram of a compensating magnetic field detection device showing another example of the second embodiment of the present invention.

FIG. 7 is a timing chart showing the operation characteristics of the embodiment.

FIG. 8 is a circuit diagram of a negative feedback type magnetic field detection device according to a third embodiment of the present invention.

FIG. 9 is a circuit diagram of a negative feedback type magnetic field detection device according to a fourth embodiment of the present invention.

FIG. 10 is a circuit diagram of a magnetic field detection device according to a modification.

FIG. 11 is a circuit diagram of a magnetic field detection device according to an application example.

FIG. 12 is a circuit diagram of a magnetic field detection device according to an application example.

FIG. 13 is an explanatory diagram showing a configuration of a magnetic sensing element of a magnetic field detection device according to a modification.

FIG. 14 is a structural diagram showing the structure of an individual element on which a magnetic sensing element is mounted.

FIG. 15 is a cross-sectional view showing a joint between the magneto-sensitive element and an electrode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Magnetic sensing element 10a, 10b ... Magnetic sensing element 12 ... Feedback excitation coil 13 ... Rectangular wave oscillator 14 ... Differentiating circuit 15 ... Switch 16 ... Signal processing circuit 17 ... Comparison return circuit 30 ... Substrate 31, 32 ... Electrode 33, 34 ... plate 35 ... gel-like substance

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Yoshinobu Honkura, Wanowari, Arao-cho, Tokai City, Aichi Prefecture Inside Aichi Steel Co., Ltd. (72) Michiharu Yamamoto, 1-Wanowari, Arao-cho, Tokai City, Aichi Prefecture Aichi Within Steelmaking Co., Ltd. (72) Inventor Kazumasa Sumi 1-Wanowari, Arao-cho, Tokai-shi, Aichi F-term within Aichi Steel Corporation (reference) 2G017 AA01 AD51 BA05 5J050 AA03 AA49 BB26 CC00 DD14 EE34 EE35 FF23

Claims (18)

[Claims] An impedance increases as the magnitude of an external magnetic field, which is a component in the detection axis direction, increases. After passing through a maximum value, the impedance changes with a decreasing magnetic impedance characteristic. In the magnetic field detection device used, it is excited in the circumferential direction by pulse current or high-frequency current,
A magneto-sensitive element whose impedance changes according to the external magnetic field; an oscillating means for supplying the pulse current or the alternating current to the magneto-sensitive element; and detecting a physical quantity related to an impedance between terminals of the magneto-sensitive element. Detecting means; biasing means for applying a bias magnetic field to the magneto-sensitive element in order to set a region where the impedance decreases as the magnitude of the external magnetic field in the magnetic impedance characteristic increases as a measurement region; A magnetic field detection device comprising: a comparison unit that compares an output signal of the unit with a predetermined level and outputs a comparison result as a binary signal. 2. The magneto-impedance effect, in which the impedance increases as the magnitude of the external magnetic field, which is a component in the direction of the detection axis, increases, passes through a maximum value, and then changes with a decreasing magnetic impedance characteristic. In the magnetic field detection device used, it is excited in the circumferential direction by pulse current or high-frequency current,
A pair of magneto-sensitive elements whose impedance changes according to the external magnetic field; an oscillating means for supplying the pulse current or the alternating current to the pair of magneto-sensitive elements; and a terminal between the pair of magneto-sensitive elements. A pair of detecting means for respectively detecting a physical quantity related to the impedance of the magnetic field, and the above-described sensing means for setting a region where the impedance decreases as the magnitude of the external magnetic field in the magnetic impedance characteristic increases as a measurement region. Means for applying a bias magnetic field to the magnetic element, such that when the magnitude of the external magnetic field increases, the internal magnetic field of the pair of magneto-sensitive elements has a relationship in which one increases and the other decreases. Bias means for applying a bias magnetic field to the pair of magneto-sensitive elements; difference output means for outputting a difference between output signals of the pair of detection means; Compared to Le, the magnetic field detecting apparatus characterized by having a comparison means for outputting a comparison result as a binary signal. 3. The comparison means includes first comparison means for comparing an input signal with a first predetermined level, and second comparison means for comparing the input signal with a second predetermined level. The magnetic field detection device according to claim 1, wherein the output signal of the second comparison unit includes information on a direction of the external magnetic field. 4. The oscillation means supplies a pulse current to the magneto-sensitive element, and is provided between the magneto-sensitive element and the detection means, and appears on the magneto-sensitive element in synchronization with the pulse current. The magnetic field detection device according to claim 1, further comprising a switch that passes only the first pulse. 5. A signal processing circuit for outputting a signal formed by a peak value of an input signal, a peak value input repeatedly, or a value related to the amplitude of an AC signal. The magnetic field detection device according to claim 1. 6. The magnetic field detecting device according to claim 1, wherein said detecting means is a peak hold circuit or an integrating circuit. 7. The magnetic field detecting device according to claim 1, wherein the biasing means is an electromagnet for supplying a direct current to the coil or a permanent magnet. 8. A negative feedback excitation coil wound in the direction of rotation of the magneto-sensitive element and generating a magnetic field for canceling the external magnetic field, which is a component in the detection axis direction, according to an output signal of the detection means. 9. The method according to claim 1, wherein
The magnetic field detection device according to any one of claims 1 to 4. 9. The magnetic field detecting device according to claim 8, wherein said negative feedback exciting coil also serves as said bias means. 10. The oscillator according to claim 1, wherein the oscillating means includes a rectangular wave oscillating circuit, and a differentiating circuit for differentiating a rectangular wave output from the rectangular wave oscillating circuit and using a differentiated signal as the pulse current. The magnetic field detection device according to claim 9. 11. The magnetic field detecting device according to claim 1, wherein the magneto-sensitive element has magnetic anisotropy in a circling direction. 12. The magnetic field detection device according to claim 1, wherein the magneto-sensitive element is an element that generates a skin effect with respect to the pulse current or the alternating current. apparatus. 13. The magnetic field detecting device according to claim 1, wherein the magneto-sensitive element is made of an amorphous magnetic material. 14. The magnetic field detecting device according to claim 1, wherein the magneto-sensitive element is a wire made of an amorphous magnetic material. 15. The magneto-sensitive element is supported and energized at both ends by electrodes formed on a substrate, and includes a space between the substrate and the magneto-sensitive element, and the periphery of the magneto-sensitive element is covered with a gel-like substance. The method according to any one of claims 1 to 14, wherein
Item 7. The magnetic field detection device according to Item. 16. The magnetic sensing element and the electrode are placed on electrodes that are supported and energized at both ends, and aluminum or an aluminum alloy is covered from above the magnetic sensing element and ultrasonically bonded to connect the magnetic sensing element and the electrode. The magnetic field detecting device according to claim 1, wherein the magnetic field detecting device is joined. 17. The method according to claim 17, wherein the electrode comprises nickel, aluminum,
17. The magnetic field detecting device according to claim 16, wherein the magnetic field detecting device is made of gold, copper, silver, tin, zinc, platinum, magnesium, rhodium, or an alloy containing at least one of these. 18. The magnetic field detecting device according to claim 17, wherein the electrode has a layer made of an aminium or aluminum alloy as a surface layer.