JP7141825B2 - magnetic sensor - Google Patents

Description

The present invention relates to magnetic sensors.

Conventionally, as a magnetic sensor capable of detecting magnetism having a plurality of axial components, a method of changing the direction of a magnetic field using a magnetic flux converging plate provided on a Hall element provided on a semiconductor substrate. (See, for example, Patent Document 1.) and a method of forming a magnetic sensing portion on an inclined surface formed on a substrate and detecting a magnetic field of multiaxial components (for example, Patent Document 2) is known.

Patent No. 3928775 specification U.S. Patent Application Publication No. 2017/0345997

As in the above-described conventional technique, when a method of changing the direction of a magnetic field using a magnetic convergence plate is used for a Hall element provided on a semiconductor substrate, the number of terminals increases, and wiring routing is limited.
Further, in the method of forming the slope on the substrate, the angle of the slope is determined by the material used, so the sensitivity direction of the magnetic sensor cannot be freely set. As a result, it becomes impossible to direct the sensitivity in the direction in which the change in the magnetic field is large, and it may be difficult to obtain a signal with a high S/N ratio.
SUMMARY OF THE INVENTION The present invention has been made by paying attention to unsolved problems in the prior art, and provides a magnetic sensor capable of obtaining a signal with a high S/N ratio and capable of measuring magnetic fields in three axial directions. It is intended to

In order to achieve the above object, a magnetic sensor according to one aspect of the present invention is a magneto-sensitive magnetic sensor that is formed on one surface of a substrate and has a predetermined thickness to have sensitivity to both a perpendicular magnetic field and an in-plane magnetic field. a plurality of electrodes arranged so as to form at least one triangle on the upper surface of the magnetically sensitive portion; a driving portion connected to one of the electrodes to drive the magnetically sensitive portion; and a plurality of connections. a computing unit having terminals; and a switch unit that switches the plurality of electrodes according to a plurality of connection patterns and connects them to the driving unit and the connection terminals, wherein the aspect ratio of the magnetic sensing unit (the (predetermined thickness/minimum distance between the plurality of electrodes) is 0.01 or more and 1 or less, and each of the connection patterns is in a plane including the three electrodes forming the triangle in which the magnetic field sensitive portion is formed. is set and stored to be sensitive to both magnetic field components in directions perpendicular to and parallel to said plane, said connection pattern comprising three connections per said triangle a pattern, wherein a first connection pattern of the three connection patterns is connected to a first electrode of the three electrodes forming the one triangle and the driving section, and the three electrodes are connected to each other; each of a second electrode and a third electrode of the three connection patterns is a pattern to be connected to the plurality of connection terminals, and the second connection pattern of the three connection patterns is connected to the second electrode and the drive and the first electrode and the third electrode are connected to the plurality of connection terminals, and the third connection pattern among the three connection patterns 3 electrodes are connected to the drive unit, and the first electrode and the second electrode are each connected to the plurality of connection terminals, wherein the calculation unit includes the magnetic sensing unit It has a preset arithmetic expression for calculating the triaxial magnetic field component representing the magnitude of the magnetic field applied to based on the triaxial magnetic field arithmetic matrix, and the arithmetic expression is obtained by the driving unit, A constant current or a constant voltage is input to the electrodes connected to the drive section for each of the three connection patterns, a known magnetic field is applied to the magnetic field sensing section, and the magnetic field sensing section is driven by the drive section. A set of output signals from the plurality of connection terminals when a conductive path is formed is obtained for each of the connection patterns, and a potential difference or current between the two connection terminals calculated for each set of the output signals. at least three differential signals indicating the difference, or by the driver, for each of the three connection patterns A constant current or a constant voltage is input to the electrode connected to the drive unit, and a potential difference between the electrode connected to the drive unit and one of the connection terminals when no magnetic field is applied is divided. A known potential difference, which is a potential difference between the electrode connected to the drive section and the other connection terminal obtained by Obtaining the three difference signals based on at least three difference signals indicating the difference between the potential difference between the electrode and the other connection terminal, and magnetic field components in three axial directions indicating the magnitude of the known magnetic field. A magnetic field to be detected is applied to the magnetic sensing section , and the computing section is driven by the driving section to form a conductive path in the magnetic sensing section. at least three potential differences or current differences between the two connection terminals calculated for each set of output signals by acquiring sets of output signals from the plurality of connection terminals when in the state two differential signals, or the known potential difference and the potential difference between the electrode connected to the drive section and the other connection terminal when the magnetic field to be detected is applied to the magnetic sensing section and the arithmetic expression corresponding to the acquisition method when these differential signals are acquired, the three axial directions of the magnetic field to be detected applied to the magnetic sensing unit It is characterized by calculating the magnetic field component and outputting it as a magnetic signal.
A magnetic sensor according to another aspect of the present invention includes: a magnetic sensing portion formed on one surface of a substrate and having a predetermined thickness so as to be sensitive to both a perpendicular magnetic field and an in-plane magnetic field; a plurality of electrodes arranged to form a plurality of triangles on the upper surface of a magnetic portion; a driving portion connected to one of the electrodes to drive the magnetic sensing portion; and a computing portion having a plurality of connection terminals. and a switch unit that switches the plurality of electrodes in a plurality of connection patterns and connects them to the driving unit and the connection terminals, wherein the aspect ratio of the magnetic sensing unit (the predetermined thickness of the magnetic sensing unit/the plurality of (minimum distance between electrodes) is 0.01 or more and 1 or less, and each of the connection patterns is in the direction perpendicular to the plane containing the three electrodes forming the triangle. configured and stored to be sensitive to both magnetic field components and magnetic field components in a direction parallel to the plane, the connection pattern being one of three electrodes forming one of the triangles; At least three connection patterns for connecting an electrode to the driving section and connecting the other two electrodes to the connection terminals are provided for the same or different triangles , It has a preset arithmetic expression for calculating the magnetic field components in the triaxial directions representing the magnitude of the magnetic field based on the triaxial magnetic field arithmetic matrix, and the arithmetic expression is operated by the driving unit for the three connections A constant current or a constant voltage is input to the electrodes connected to the driving section for each pattern, a known magnetic field is applied to the magnetic sensing section, and a conductive path is formed in the magnetic sensing section by being driven by the driving section. A set of output signals from the plurality of connection terminals in the connected state is acquired for each of the connection patterns, and at least a potential difference or a current difference between the two connection terminals calculated for each set of the output signals is indicated. A constant current or a constant voltage is input to the electrodes connected to the drive unit for each of the three connection patterns by the three differential signals or the drive unit, and a constant current or constant voltage is applied to the drive unit when no magnetic field is applied. a known potential difference, which is a potential difference between the electrode connected to the drive unit and the other connection terminal obtained by dividing the potential difference between the connected electrode and one of the connection terminals; At least three difference signals indicating the difference between the potential difference between the electrode connected to the drive unit and the other connection terminal when a known magnetic field is applied to the magnetic unit, and the magnitude of the known magnetic field. The three differential signals were obtained based on the three axial magnetic field components representing A state in which a magnetic field to be detected is applied to the magnetic field sensing section and is driven by the driving section to form a conductive path in the magnetic field sensing section. At least three sets of output signals from the plurality of connection terminals are obtained for each of the connection patterns, and the potential difference or the current difference between the two connection terminals calculated for each set of output signals. a difference signal, or the known potential difference, and a potential difference between the electrode connected to the drive section and the other connection terminal when the magnetic field to be detected is applied to the magnetic sensing section; and the arithmetic expression corresponding to the acquisition method when acquiring these differential signals, the magnetic field in the three axial directions of the magnetic field to be detected applied to the magnetic sensing unit It is characterized by calculating the component and outputting it as a magnetic signal.

According to one aspect of the present invention, a magnetic sensor that can obtain a signal with a high S/N ratio and can measure magnetic fields in three axial directions can be realized.

1 is a schematic configuration diagram showing an example of a magnetic sensor according to one embodiment of the present invention; FIG. FIG. 4 is a plan view showing an example in which four electrodes are arranged in a rotationally symmetrical manner; It is a schematic equivalent circuit for explaining the method of driving the magnetic sensor. It is a schematic equivalent circuit for explaining the method of driving the magnetic sensor. It is a schematic equivalent circuit for explaining the method of driving the magnetic sensor. It is a schematic equivalent circuit for explaining the method of driving the magnetic sensor. It is a schematic equivalent circuit for explaining the method of driving the magnetic sensor. It is a schematic equivalent circuit for explaining the method of driving the magnetic sensor. It is a schematic equivalent circuit for explaining the method of driving the magnetic sensor. FIG. 4 is an explanatory diagram for explaining a method of calculating magnetic field strengths in three axial directions; FIG. 4 is an explanatory diagram for explaining a method of calculating magnetic field strengths in three axial directions; It is a schematic equivalent circuit for explaining a method of removing an offset component. It is a schematic equivalent circuit for explaining a method of removing an offset component.

In the following detailed description, a number of specific specific configurations are set forth in order to provide a thorough understanding of the embodiments of the invention. However, it is evident that other embodiments may be practiced without being limited to such specific specific configurations. Moreover, the following embodiments do not limit the invention according to the claims, but include all combinations of characteristic configurations described in the embodiments.
An embodiment of the present invention will be described below with reference to the drawings. In the description of the drawings below, the same reference numerals are given to the same parts. However, the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones.

[Configuration of magnetic sensor]
FIG. 1 is a block diagram showing a schematic configuration showing an example of a magnetic sensor 1 for detecting magnetic field intensities in three axial directions according to one embodiment of the present invention.
The magnetic sensor 1 includes a Hall element 2 as a detector, and a signal processing unit 3 that receives an output signal from the Hall element 2, performs signal processing, and outputs triaxial magnetic field measurement signals Bx, By, and Bz.
The Hall element 2 includes a substrate 11, a magnetic field sensing portion 12 formed on one side of the substrate 11, and a magnetic field sensing portion 12 formed on one side of the substrate 11 and electrically connected to the magnetic field sensing portion 12, similarly to the conventional Hall device. In the Hall element 2 of the present embodiment, the film thickness of the magnetically sensitive portion 12 is thicker than that of the conventional Hall element. The magnetic sensing portion 12 is formed with a thickness that is sensitive to both the perpendicular magnetic field and the in-plane magnetic field. Specifically, the magnetic field sensing portion 12 is formed, for example, in the shape of a triangular prism, and the electrodes 13a to 13c are arranged on the upper surface of the triangular prism in plan view near the positions of the vertices of the triangle. The magnetically sensitive portion 12 formed in the shape of a triangular prism has a thickness that satisfies an aspect ratio (thickness of the magnetically sensitive portion 12/minimum distance between the electrodes 13a to 13c) of 0.01 or more and 1 or less.

In this specification, the thickness of the magneto-sensitive portion indicates the thickness of a semiconductor region having a high impurity concentration with respect to the substrate, and can be measured, for example, by secondary ion mass spectrometry (SIMS) in the thickness direction of the Hall element 2 .
The aspect ratio of the magnetic field sensitive portion 12 may be 0.02 or more, or 0.05 or more. If the aspect ratio of the magnetic field sensing portion 12 is within this range, the sensitivity to the in-plane magnetic field is increased, which is preferable.
Although there is no particular upper limit to the aspect ratio of the magneto-sensitive portion 12, it may be 0.5 or less or 0.1 or less in view of ease of manufacture.
In addition, the thickness of the magnetic sensing portion is preferably 0.5 μm or more in order to increase the sensitivity to the in-plane magnetic field. Although there is no particular upper limit, it is preferably 10 μm or less from the viewpoint of ease of production.
The method of manufacturing the Hall element 2 is similar to that of the conventional Hall element whose magnetically sensitive portion is made of a thin film. The thickness of the magnetic portion/minimum distance between electrodes (terminals) is 0.01 or more and 1 or less.

Further, the shape of the magnetic field sensing portion 12 is not limited to a triangular prism shape, and may be any shape such as a rectangular parallelepiped shape as long as it has a thickness that is sensitive to both the perpendicular magnetic field and the in-plane magnetic field. .
In the Hall element 2, one of the three electrodes 13a to 13c serves as a driving terminal of the Hall element 2, and the remaining two electrodes serve as output terminals of the Hall element 2. FIG. Although the case where three electrodes 13a to 13c are provided is described here, the number of electrodes is not limited to three and may be four or more.

The substrate 11 is formed with the magnetic sensing portion 12 directly or via an insulating layer or the like, and may be a semiconductor substrate or an insulating substrate. The semiconductor substrate may be a silicon substrate, a compound semiconductor substrate, or the like, and the insulating substrate may be, for example, a ceramic substrate. The substrate 11 may have an electric circuit formed in or on the substrate 11 .
The magnetic field sensing portion 12 is formed on one surface of the substrate 11, and serves as a drive terminal or a first conductive path through which a drive current flows between, for example, an electrode 13a, which serves as a drive terminal, and, for example, an electrode 13b, which serves as one output terminal. A second conductive path is integrally formed between the electrode 13a and the other output terminal, for example, the electrode 13c, through which the drive current flows. The magnetic field sensing portion 12 is a portion to which a magnetic field is applied, and resistance changes occur in the first conductive path and the second conductive path in the magnetic field sensing portion 12 due to the Lorentz force according to the applied magnetic field.

In FIG. 1, the electrodes 13a to 13c are arranged in the vicinity of the vertices of the triangle of the magnetic field sensing portion 12 having a triangular prism shape in a plan view, but the present invention is not limited to this. It suffices if they are arranged so as to form at least one triangle with vertices 13a to 13c. When four or more electrodes are provided, any three of the plurality of electrodes may be arranged so as to form at least one triangle.
An equilateral triangle is preferable as the triangle formed by such three electrodes. By forming an equilateral triangle, it is possible to set, as a connection pattern to be described later, a pattern that obtains sensitivity vectors that are independent of each other and have equal absolute values in the sensitivity vectors to be described later.

Alternatively, an isosceles triangle having the electrodes as vertices may be formed. By forming an isosceles triangle, the distances from the drive terminal to the two output terminals become equal as a connection pattern, which will be described later, so that a pattern that can obtain a signal with less offset components can be set.
In particular, when four or more electrodes are provided, a plurality of such isosceles triangles may be formed. In this case, at least two isosceles triangles are preferably formed, and at least three areosceles triangles are preferably formed. is more preferred. By arranging the electrodes in this way, it is possible to set a plurality of patterns that can obtain signals with less offset components.

Furthermore, the electrodes may be arranged at positions that are rotationally symmetrical in a plan view. Since the electrodes are formed at rotationally symmetrical positions, it is possible to set a plurality of patterns in which a plurality of isosceles triangles are formed and signals with less offset components can be obtained, and the amount of calculation in the calculation unit 20 described later. can be reduced, and the calculation load in the calculation unit 20 can be reduced. In this case, the n electrodes may be arranged at m-fold rotational symmetry (where n≧3 and m is an integer satisfying 3≦m≦n).

For example, the electrodes 13a to 13c may be arranged at positions having three-fold rotational symmetry (that is, positions forming an equilateral triangle) (hereinafter also referred to as three-fold rotational symmetry).
When four or more electrodes are provided, they may be arranged at positions having three-fold rotational symmetry, or may be arranged at positions having four-fold rotational symmetry. That is, as shown in FIG. 2(a), three of the four electrodes may be arranged at positions forming a triangle, and the remaining one electrode may be arranged inside the triangle. Alternatively, as shown in FIG. 2B, four electrodes may be arranged at the vertices of a square.

Here, the case where the electrodes 13a to 13c are arranged on the magnetic sensing portion 12 whose upper surface is flat in plan view has been described, but the present invention is not limited to this. For example, the magnetic sensing part 12 may be formed in a stepped shape, and three or four or more electrodes may be arranged at different height positions. Further, in the magnetic sensing portion 12 formed in a triangular prism shape, for example, the electrodes 13a to 13c may be arranged on any three surfaces of the triangular prism.
The signal processing section 3 includes a switch section 21 , a drive section 22 and a calculation section 20 , and the calculation section 20 includes detection sections 23 a and 23 b , an output section 24 and a calculation processing section 25 .

The switch unit 21 switches connection patterns between the electrodes 13a to 13c, the drive unit 22, and the detection units 23a and 23b, and switches the electrodes 13a to 13c connected to the drive unit 22 and the detection units 23a and 23b, respectively. . That is, the switch section 21 switches the connection between the electrodes 13a to 13c, the drive section 22, and the detection sections 23a and 23b to three connection patterns with different connection destinations. The drive section 22 and the detection sections 23a and 23b each have a connection terminal. In the switch section 21, the electrodes 13a to 13c are connected to the connection terminals of the drive section 22 and the detection sections 23a and 23b. Each of the connection patterns is sensitive to both magnetic field components in the direction perpendicular to the plane containing the three electrodes 13a to 13c and to magnetic field components in the direction parallel to this plane. is set to

The drive unit 22 drives the Hall element (detector) 2 . The detectors 23a and 23b extract detector outputs from any two of the electrodes 13a to 13c through the switch 21 and output them to the output 24. FIG.
The output unit 24 acquires a signal consisting of the potential difference between the terminals of the two electrodes connected to the detection units 23a and 23b or the current difference flowing through the two electrodes based on the input signals input from the detection units 23a and 23b. , a signal representing the potential difference or the current difference is output to the arithmetic processing unit 25 as a difference signal Si (i=1 to 3, i is a variable representing each connection pattern).
The arithmetic processing unit 25 stores the difference signal Si input from the output unit 24, for example, in a storage area 25a provided in the arithmetic processing unit 25, and the electrodes 13a to 13c, the driving unit 22, and the detecting units 23a and 23b. After obtaining the difference signal Si for each of the three connection patterns with different connection destinations, the three signals representing the magnetic field strength in the three axial directions are obtained based on the difference signal Si for the three connection patterns stored in the storage area 25a. It calculates and outputs axial magnetic field measurement signals Bx to Bz.

[Method for Driving Hall Element]
Next, a method of driving the Hall element (detector) 2 will be described.
Here, the case where the electrodes 13a to 13c are arranged in a three-fold rotational symmetry will be described.
(First driving method)
First, the first driving method will be explained.
FIG. 3 is a schematic equivalent circuit of the Hall element 2 portion for explaining a driving method when the Hall element 2 is driven with a constant current.
In FIG. 3, T1 is a drive terminal, and T2 and T3 are output terminals. Among the electrodes 13a to 13c, the electrode connected to the drive unit 22 by the switch unit 21 becomes the drive terminal T1, the electrode connected to the detection unit 23a becomes the output terminal T2, and the electrode connected to the detection unit 23b is output. It becomes the terminal T3.
In the first driving method, as shown in FIG. 3, the drive terminal T1 is connected to the power supply, the output terminal T2 is connected to the signal ground potential via the constant current source 31a, and similarly the output terminal T3 is connected to the constant current potential. Connected to signal ground potential via current source 31b. Then, the same constant current Ic is drawn from the two output terminals T2 and T3. A potential difference generated between the output terminals T2 and T3 at this time is acquired as a differential signal Si. That is, the voltage detector 32 detects the potential difference ΔV between the output terminal T2 and the output terminal T3, and the output of the voltage detector 32 is the difference obtained when the Hall element 2 is driven in the connection pattern shown in FIG. obtained as a signal Si.

When the electrodes 13a to 13c are arranged in a three-fold rotational symmetry, and no magnetic field is applied to the magnetic field sensing portion 12, in FIG. The resistance r1+r3 in the conductive path from the drive terminal T1 to the output terminal T3 is substantially the same. Therefore, the potential difference ΔV between the output terminal T2 and the output terminal T3 becomes substantially zero.
On the other hand, when a magnetic field is applied to the magnetic field sensing portion 12, between the resistance r1+r2 in the conductive path from the drive terminal T1 to the output terminal T2 and the resistance r1+r3 in the conductive path from the drive terminal T1 to the output terminal T3 , there is a difference depending on the magnitude of the applied magnetic field. Therefore, a potential difference occurs between the output terminals T2 and T3, and this difference becomes the potential difference ΔV, that is, the difference signal Si.

Here, in FIG. 3, the potential difference ΔV between the output terminals T2 and T3 can be expressed by the following equation (1).
ΔV=((Gsi)/net)IB (1)
In equation (1), Gsi is a geometric factor that is a preset coefficient determined by the shape of the magnetically sensitive portion 12, n is the carrier density, e is the elementary charge, t is the film thickness of the magnetically sensitive portion 12, and I is Input current, B is the magnetic flux density.

In the magnetic sensor 1 shown in FIG. 1, the switch section 21 sequentially switches the connections between the drive section 22, the detection sections 23a and 23b, and the electrodes 13a to 13c. Then, the potential difference ΔV in each of the three different connection patterns is detected by the detection units 23a and 23b and the output unit 24. FIG. This makes it possible to acquire differential signals Si in three different connection patterns. The detection units 23a and 23b and the output unit 24 shown in FIG. 1 correspond to the voltage detector 32 shown in FIG.

(Second driving method)
Next, the second driving method will be explained.
FIG. 4 is a schematic equivalent circuit of the Hall element 2 portion for explaining a driving method when the Hall element 2 is driven at a constant voltage.
In FIG. 4, T1 is a drive terminal, and T2 and T3 are output terminals.
As shown in FIG. 4, drive terminal T1 is connected to voltage source 41, output terminal T2 is connected to signal ground potential, and output terminal T3 is connected to signal ground potential. A constant voltage Vc is input to the drive terminal T1 by the voltage source 41, and the current flowing from the drive terminal T1 to the output terminal T2 at this time is detected by the current detector 42, and the current flowing from the drive terminal T1 to the output terminal T3 is detected. is detected by the current detector 43, and the difference between the currents detected by the current detectors 42 and 43 (hereinafter referred to as output current difference) ΔI is obtained. This output current difference ΔI becomes the difference signal Si. In FIG. 4, r12 represents the resistance of the conductive path from the drive terminal T1 to the output terminal T2, r31 represents the resistance of the conductive path from the drive terminal T1 to the output terminal T3, and r23 represents the resistance of the output terminal T2. It represents the resistance in the conductive path between the output terminal T3.

When the electrodes 13a to 13c are arranged in a three-fold rotational symmetry, in the state in which no magnetic field is applied to the magnetic sensing part 12, in FIG. The current flowing through the conductive path from the drive terminal T1 to the output terminal T3 is substantially the same, and the output current difference ΔI is substantially zero.
On the other hand, when a magnetic field is applied to the magnetic field sensing portion 12, between the resistance r12 in the conductive path from the drive terminal T1 to the output terminal T2 and the resistance r31 in the conductive path from the drive terminal T1 to the output terminal T3, A difference occurs depending on the magnitude of the applied magnetic field. Therefore, a difference occurs between the current flowing through the conductive path from the drive terminal T1 to the output terminal T2 and the current flowing through the conductive path from the drive terminal T1 to the output terminal T3, and this difference is detected as the output current difference ΔI. and this output current difference ΔI becomes the difference signal Si.

In FIG. 4, the current difference between the current flowing through the output terminal T2 and the current flowing through the output terminal T3, that is, the output current difference ΔI can be expressed by the following equation (2).
ΔI=Gsvμ ² net BV (2)
In equation (2), Gsv is the geometric factor, μ is the mobility, n is the carrier density, e is the elementary charge, t is the film thickness of the magneto-sensitive portion 12, B is the magnetic flux density, and V is the drive by the voltage source 41. is the input voltage to terminal T1.

In the magnetic sensor 1 shown in FIG. 1, similarly to the first driving method, the switching section 21 sequentially switches the electrodes 13a to 13c connected to the driving section 22 and the detecting sections 23a and 23b. Then, the output current difference ΔI in the three different connection patterns is detected by the detection units 23a and 23b and the output unit 24 shown in FIG. This makes it possible to acquire differential signals Si in three different connection patterns.

(Third driving method)
Next, a third driving method will be explained.
FIG. 5 is a schematic equivalent circuit of the Hall element 2 portion for explaining the third driving method.
The equivalent circuit shown in FIG. 5 is obtained by providing a constant current circuit 51 in place of the voltage source 41 in the equivalent circuit for constant voltage driving of the Hall element 2 shown in FIG. A constant current Ic is input to the drive terminal T1, and the difference between the current flowing from the drive terminal T1 to the output terminal T2 and the current flowing from the drive terminal T1 to the output terminal T3 is detected as the output current difference ΔI.

In this case also, when no magnetic field is applied to the magnetic field sensing portion 12, the current flowing from the drive terminal T1 to the output terminal T2 is substantially the same as the current flowing from the drive terminal T1 to the output terminal T3. On the other hand, when a magnetic field is applied to the magnetic field sensing portion 12, the current flowing from the drive terminal T1 to the output terminal T2 and the current flowing from the drive terminal T1 to the output terminal T3 vary depending on the magnitude of the applied magnetic field. there is a difference. This output current difference ΔI is acquired as a differential signal Si.
In the magnetic sensor 1 shown in FIG. 1, similarly to the second driving method shown in FIG. is detected by the detection units 23a and 23b and the output unit 24 shown in FIG. This makes it possible to obtain the difference signal Si in three different connection patterns.

(Fourth driving method)
Next, a fourth driving method will be explained.
FIG. 6 is a schematic equivalent circuit of the Hall element 2 portion for explaining the fourth driving method.
The equivalent circuit shown in FIG. 6 is the equivalent circuit in the third driving method shown in FIG. is provided with a variable voltage source 53. A constant current Ic is input to the drive terminal T1, and the difference between the current flowing from the drive terminal T1 to the output terminal T2 and the current flowing from the drive terminal T1 to the output terminal T3 is detected as the output current difference ΔI. The voltages applied by the variable voltage sources 52 and 53 are adjusted so that the output current difference ΔI becomes zero.

In this case also, when no magnetic field is applied to the magnetic field sensing portion 12, the current flowing from the drive terminal T1 to the output terminal T2 is substantially the same as the current flowing from the drive terminal T1 to the output terminal T3. On the other hand, when a magnetic field is applied, a difference occurs between the current flowing from the drive terminal T1 to the output terminal T2 and the current flowing from the drive terminal T1 to the output terminal T3 according to the magnitude of the applied magnetic field. In the equivalent circuit shown in FIG. 6, variable voltage sources 52 and 53 apply a voltage that cancels out the output current difference ΔI between the current flowing from the drive terminal T1 to the output terminal T2 and the current flowing from the drive terminal T1 to the output terminal T3. The voltage is applied to T2 and T3, and the voltage difference between the voltage applied by the variable voltage source 52 and the voltage applied by the variable voltage source 53 at this time is obtained as a differential signal Si.

In the magnetic sensor 1 shown in FIG. 1, similarly to the second driving method shown in FIG. In each connection pattern, the detection units 23a and 23b and the output unit 24 detect an output current difference ΔI between the current flowing from the drive terminal T1 to the output terminal T2 and the current flowing from the drive terminal T1 to the output terminal T3. Further, the output section 24 adjusts the voltages applied by the variable voltage sources 52 and 53 so as to cancel the output current difference ΔI detected by the output section 24, and outputs the difference between the adjusted voltages applied by the variable voltage sources 52 and 53 as a difference signal. It can be acquired as Si. The processing for acquiring this difference signal Si may be executed by the output unit 24 or by the arithmetic processing unit 25. Separately, the voltages applied by the variable voltage sources 52 and 53 may be adjusted. and outputting the difference between the voltages applied by the variable voltage sources 52 and 53 as the difference signal Si. Thereby, it is possible to acquire the differential signal Si in three different connection patterns.

(Fifth driving method)
Next, a fifth driving method will be described.
FIG. 7 is a schematic equivalent circuit of the Hall element 2 portion for explaining the fifth driving method.
The equivalent circuit shown in FIG. 7 is obtained by providing a voltage source 55 instead of the constant current circuit 51 in the equivalent circuit in the fourth driving method shown in FIG. A constant voltage Vc is input to the drive terminal T1 by the voltage source 55, and the difference between the current flowing from the drive terminal T1 to the output terminal T2 and the current flowing from the drive terminal T1 to the output terminal T3 is detected as the output current difference ΔI. The voltages applied by the variable voltage sources 52 and 53 are adjusted so that the output current difference ΔI becomes zero.

In this case also, when no magnetic field is applied to the magnetic field sensing portion 12, the current flowing from the drive terminal T1 to the output terminal T2 is substantially the same as the current flowing from the drive terminal T1 to the output terminal T3. On the other hand, when a magnetic field is applied, a difference occurs between the current flowing from the drive terminal T1 to the output terminal T2 and the current flowing from the drive terminal T1 to the output terminal T3 according to the magnitude of the applied magnetic field. . In the equivalent circuit shown in FIG. 7, variable voltage sources 52 and 53 apply a voltage to the output terminal by variable voltage sources 52 and 53 to cancel the output current difference ΔI between the current flowing from the driving terminal T1 to the output terminal T2 and the current flowing from the driving terminal T1 to the output terminal T3. The voltage is applied to T2 and T3, and the voltage difference between the voltage applied by the variable voltage source 52 and the voltage applied by the variable voltage source 53 at this time is obtained as a differential signal Si.

In the magnetic sensor 1 shown in FIG. 1, the connection destinations of the electrodes 13a to 13c are sequentially switched by the switch section 21 as in the fourth driving method. In each connection pattern, the detection units 23a and 23b and the output unit 24 detect an output current difference ΔI between the current flowing from the drive terminal T1 to the output terminal T2 and the current flowing from the drive terminal T1 to the output terminal T3. Furthermore, the output unit 24 or the arithmetic processing unit 25 or separately performs a process of adjusting the voltage applied by the variable voltage sources 52 and 53 and a process of outputting the difference between the voltages applied by the variable voltage sources 52 and 53 as a difference signal Si. The difference signal Si in three different connection patterns may be acquired by the processing unit.

(Sixth driving method)
Next, a sixth driving method will be described.
FIG. 8 is a schematic equivalent circuit of the Hall element 2 portion for explaining the sixth driving method.
A sixth driving method, as shown in the equivalent circuit of FIG. 8, acquires as an output the fluctuation of the midpoint potential when a constant voltage is input.
As shown in FIG. 8, drive terminal T1 is connected to voltage source 61, output terminal T2 is connected to signal ground potential, and output terminal T3 is connected to signal ground potential. A constant voltage Vc is input to the drive terminal T1, and the voltage detector 62 detects the potential of the output terminal T3. A change in the potential of the output terminal T3 due to the application of the magnetic field becomes the difference signal Si.

When the electrodes 13a to 13c are arranged in a three-fold rotational symmetry, when no magnetic field is applied, in FIG. and the resistance r23 in the conductive path between the output terminal T2 and the output terminal T2 are substantially the same, and the potential of the output terminal T3 is substantially the same as the midpoint potential. Here, the midpoint potential is a potential obtained by dividing the potential difference between the drive terminal T1 and the output terminal T2 by the resistors r31 and r23 when no magnetic field is applied to the magnetic sensing section 12 . This midpoint potential is detected in advance for each connection pattern and stored in the storage area 25a, for example.

On the other hand, when a magnetic field is applied, a difference occurs between the resistors r31 and r23 according to the strength of the applied magnetic field, and the potential of the output terminal T3 fluctuates according to the resulting resistance difference. do. That is, the potential of the output terminal T3 does not match the midpoint potential. A potential difference between the output terminal T3 and the midpoint potential is obtained as a differential signal Si.
In the magnetic sensor 1 shown in FIG. 1, the switch section 21 sequentially switches the electrodes 13a to 13c connected to the drive terminal T1, the output terminal T2, and the output terminal T3. The detection units 23a and 23b and the output unit 24 detect the voltage of the output terminal T3 in each connection pattern, and output the difference between the potential of the output terminal T3 and the midpoint potential as a difference signal Si. Thereby, it is possible to acquire the difference signal Si in each of the three different connection patterns.

(Seventh driving method)
Next, the seventh driving method will be explained.
FIG. 9 is a schematic equivalent circuit of the Hall element 2 portion for explaining the seventh driving method.
The seventh driving method, as shown in the equivalent circuit of FIG. 9, obtains as an output the change in the midpoint potential when the constant current Ic is input.
As shown in FIG. 9, drive terminal T1 is connected to current source 63, output terminal T2 is connected to signal ground potential, and output terminal T3 is connected to signal ground potential. A constant current Ic is input to the drive terminal T1, and the voltage detector 64 detects the potential of the output terminal T3. A change in the potential of the output terminal T3 due to the application of the magnetic field becomes the differential signal Si.

When the electrodes 13a to 13c are arranged in a three-fold rotational symmetry and no magnetic field is applied, in FIG. are substantially the same, and the potential of the output terminal T3 is substantially the same as the midpoint potential. The term "midpoint potential" as used herein refers to the potential difference between the drive terminal T1 and the output terminal T2 when no magnetic field is applied to the magnetic sensing section 12, which is the potential divided by the resistors r1 and r2. . This midpoint potential is detected in advance for each connection pattern and stored in the storage area 25a, for example.

On the other hand, when a magnetic field is applied, a difference corresponding to the strength of the applied magnetic field is generated between the resistors r1 and r2, and the potential of the output terminal T3 is generated between the resistors r1 and r2. It fluctuates according to the resistance difference. That is, the potential of the output terminal T3 does not match the midpoint potential. A potential difference between the output terminal T3 and the midpoint potential is obtained as a differential signal Si.
In the magnetic sensor 1 shown in FIG. 1, the switch section 21 sequentially switches the electrodes 13a to 13c connected to the drive terminal T1, the output terminal T2, and the output terminal T3. The detection units 23a and 23b and the output unit 24 detect the voltage of the output terminal T3 in each connection pattern, and output the difference between the potential of the output terminal T3 and the midpoint potential as a difference signal Si. Thereby, it is possible to acquire the difference signal Si in each of the three different connection patterns.

[Calculation method of magnetic field intensity in three axial directions]
Next, an acquisition method for acquiring magnetic field strengths in three axial directions from differential signals Si in three different connection patterns will be described. Note that the computation for obtaining the magnetic field strength in these three axial directions is executed by the computation processing unit 25 .
10A and 10B are explanatory diagrams for explaining the sensitivity vector of the magnetic sensing portion 12 included in the Hall element 2. FIG. shows an example in which the magnetic sensing portion is formed of a thick-film semiconductor. Also, FIG. 10 shows a case where three electrodes are formed in the magnetic sensing portion.
As shown in FIG. 10(a), when the magnetic sensing portion is formed of a thin film semiconductor, that is, when formed of a two-dimensional thin film, the magnetic sensing portion has sensitivity only to a perpendicular magnetic field. Therefore, even if a magnetic field having a vector shown in FIG. 10(c) is applied to the magnetic field sensing portion, the magnetic field sensing portion shown in FIG. 10(a) can detect only the magnetic field strength in the perpendicular direction.

As shown in FIG. 10(b), when the magnetic sensing portion is formed of a thick-film semiconductor, the magnetic sensing portion has sensitivity in the direction perpendicular to the plane, and also sensitivity to the in-plane magnetic field (transverse magnetic field) of the thick-film semiconductor. have. That is, as shown in FIG. 10(b), when the vector representing the sensitivity in the direction perpendicular to the plane is defined as the in-plane sensitivity vector Mmα and the vector representing the sensitivity to the in-plane magnetic field is defined as the in-plane sensitivity vector Mmβ, the magnetic sensing part is , a vector in the direction obtained by synthesizing the in-plane sensitivity vector Mmα and the in-plane sensitivity vector Mmβ, that is, the synthesized sensitivity vector Mm, and has sensitivity to the oblique magnetic field. That is, it has sensitivity in the vector direction of the magnetic field shown in FIG. 10(c).

FIG. 11 is for explaining the calculation method of the magnetic field strength in the three axial directions when the electrodes 13a to 13c are arranged in a three-fold rotational symmetry, that is, arranged at angular intervals of 120 degrees. It is an explanatory diagram. For example, as shown in FIG. 11A, when the electrode 13a is the driving terminal, and the electrodes 13b and 13c are the output terminals T2 and T3, respectively (first phase), the magnetic field sensing portion 12 is shown in FIG. has a sensitivity vector in the direction indicated by Mi (i=1). FIG. 11(b) represents the sensitivity vector when FIG. 11(a) is viewed from above. FIG. 11(c) shows a case where the electrode 13b is the drive terminal T1 (second phase) in FIG. 11(a), and FIG. Sensitivity vectors M2 and M3 in a planar view are represented when T1 (third phase).

Here, the sensitivity vector Mi in the i phase can be expressed by the following equation (3). Note that i=i-th phase. That is, it is a variable representing each connection pattern. Here i=1-3. In the formula, Miα represents the i-th phase in-plane sensitivity vector, and Miβ represents the ith-phase in-plane sensitivity vector.
Mi=Miα+Miβ (3)

That is, the sensitivity vector Mi in the first to third phases when the magnetic field vector B shown in FIG.
M1=M1α+M1β
M2=M2α+M2β
M3=M3α+M3β (4)
Vector calculation is performed so that the sensitivity vector obtained by synthesizing the three equations represented by equation (4) has only one directional component of the three axes.

Here, when the electrodes 13a to 13c are arranged in a three-fold rotational symmetry, the sensitivity vectors M1 to M3 have the relationship represented by the following equation (5).
ΣMiβ=0 (i=1 to 3)
M1α=M2α=M2α (5)

Therefore, the sensitivity vector of each axial component can be expressed by the following equation (6). Mx represents the sensitivity vector of the X-axis direction component, My represents the sensitivity vector of the Y-axis direction component, and Mz represents the sensitivity vector of the Z-axis direction component.
Mx=2M1-M2-M3=2M1β-M2β-M3β
My=M2-M3=M2β-M3β
Mz=M1+M2+M3=M1α+M2α+M3α (6)
That is, the X-axis direction component Mx can be calculated only from the in-plane sensitivity vectors M1β to M3β in the first to third phases. The Y-axis direction component My can be calculated only from the in-plane sensitivity vectors M2β and M3β in the first to third phases. Furthermore, the Z-axis direction component Mz can be calculated only from the surface sensitivity vectors M1α to M3α in the first to third phases.

Here, the differential signal Si output from the Hall element 2 in the i-th phase can be expressed by the following equation (7). Note that Mij in the equation (7) represents the sensitivity of the j-direction component in the i-th phase, and Bj represents the j-direction component of the magnetic field applied to the magnetic sensing section 12 . j=X-axis, Y-axis, Z-axis.
Si=MixBx+MiyBy+MizBz (7)
When the difference signal Si represented by the equation (7) is represented by a matrix with i=1 to n, it can be represented by the following equation (8). From the equation (8), the magnetic field of each component in the three axial directions is It can be seen that it is obtained from the equation (9).
If the calculation matrix for calculating the magnetic field of each component in the three axial directions is expressed in a general form, it can be expressed by the following equation (10). Note that the matrix M represented by the formula (10) is hereinafter referred to as a triaxial magnetic field calculation matrix (general form).

In addition, "†" in (9) expresses that it is a general inverse matrix.
From equation (9), each magnetic field component in the triaxial direction has an inverse matrix M ^† of the triaxial magnetic field calculation matrix (general form) M (detM≠0). I know there is. For example, the inverse matrix M ^† does not exist if the three electrodes 13a-13c are arranged on the same straight line. That is, in order for the inverse matrix M ^† to exist, the three electrodes 13a to 13c must be arranged at positions forming a triangle.

[Method for removing offset components]
Next, a method for removing the offset component of the Hall element 2 will be described.
(When driven by the constant current drive method)
When the Hall element 2 in which the electrodes 13a to 13c are arranged in three-fold rotational symmetry as shown in FIG. 12 is driven by the constant current driving method shown in FIG. It can be represented by the equivalent circuit shown in (a). When no magnetic field is applied to the magnetic field sensing portion 12, the resistance of the conductive path from the electrode serving as the drive terminal T1 to the output terminal T2 is substantially the same as the resistance of the conductive path from the drive terminal T1 to the output terminal T3. , only the potential difference corresponding to the difference between the resistance r2 and the resistance r3 caused by slight asymmetry of the magnetic field sensing portion 12 is output as the offset component Vu. When a magnetic field is applied to the magnetic field sensing portion 12, a magnetic field is applied between the resistance in the conductive path from the drive terminal T1 to the output terminal T2 and the resistance in the conductive path from the drive terminal T1 to the output terminal T3. A difference corresponding to the magnetic field is generated, and a potential difference of the magnetoelectric conversion component Vh corresponding to the resistance difference is output between the output terminals T2 and T3.
A potential difference V23 between the output terminals T2 and T3 when a magnetic field is applied to the magnetic sensing section 12 can be expressed by the following equation (11).
V23=V2-V3=Vu+Vh (11)

Next, as shown in FIG. 12(b), a constant current Ic is passed from the output terminal T2 to the output terminal T3. At this time, as shown in FIG. 12(b), a conductive path is formed in the magnetic sensing section 12 from the output terminal T2 to the output terminal T3. That is, the current flowing through the resistor r2 is opposite to that shown in FIG. 12(a). When no magnetic field is applied to the magnetic sensing part 12, the resistances r2 and r3 between the output terminals T2 and T3 are substantially the same, and the potential of the drive terminal T1 is the intermediate value of the potential difference V23c generated between the output terminals T2 and T3. (hereinafter referred to as the potential difference intermediate value), that is, V23c/2. Here, the potential difference V23c is a potential difference that occurs across the output terminals T2 and T3 when the constant current Ic is applied between the output terminals T2 and T3. Due to the slight asymmetry of the magnetic sensing part 12, a resistance difference occurs between the resistance r2 and the resistance r3, and half of the offset component Vu corresponding to the resistance difference between the potential of the drive terminal T1 and the potential difference intermediate value V23c/2. A potential difference corresponding to When a magnetic field is applied to the magnetic field sensing portion 12, a difference corresponding to the applied magnetic field is generated between the resistor r2 and the resistor r3 between the output terminals T2 and T3, and the potential of the drive terminal T1 and the potential difference A potential difference corresponding to half of the magnetoelectric conversion component Vh corresponding to the resistance difference appears between the intermediate value V23c/2 and is detected by the voltage detector as a voltage value whose sign is inverted.

At this time, the potential difference V23' between the potential of the drive terminal T1 and the potential difference intermediate value V23c/2 can be expressed by the following equation (12).
V'23=V1-V23c/2=(Vu-Vh)/2 (12)
Therefore, from "V23" (potential difference between output terminals T2 and T3) detected in the equivalent circuit shown in FIG. 12(a), "V'23" (drive terminal T1) detected in the equivalent circuit shown in FIG. and the intermediate value V23c/2) of the potential difference between the output terminals T2 and T3, which does not include the offset component of the Hall element 2 and corresponds to the strength of the applied magnetic field. can obtain a differential signal Si consisting of a potential difference corresponding to the resistance difference of .

In each connection pattern according to the above-described procedure, a differential signal Si composed of a voltage corresponding to the resistance difference between the output terminals T2 and T3, which does not include the offset component of the Hall element 2, is obtained, and the magnetic field is calculated based on these signals. , the magnetic field intensity can be obtained in which the influence of the offset component of the Hall element 2 is reduced.
Specifically, for every three connection patterns, as shown in FIG. 12(b), a constant current Ic is passed from the output terminal T2 to the output terminal T3 to offset the potential difference between the potential of the drive terminal T1 and the potential difference intermediate value V23c/2. and obtaining a signal "V'23" containing the component Vu and the sign-inverted magnetoelectric conversion component Vh. That is, when obtaining the differential signal Si corresponding to the three connection patterns, predetermined signals are obtained in two phases for each connection pattern, for a total of six phases.

It should be noted that the process of obtaining the difference signal Si from which the offset component has been removed is performed in the output unit 24, for example. 12(a) and the conductive path shown in FIG. 12(b) are formed by the switch unit 21, for example. That is, in the switch section 21, for example, first, the electrode 13a (drive terminal T1) and the drive section 22, the electrode 13b (output terminal T2) and the electrode 13c (output terminal T3) are connected to the detection section 23a and the detection section 23b, respectively. Then, the difference signal Si is acquired in this state. Next, the electrode 13a and the drive unit 22 are cut off, the electrode 13b is connected to the constant current source 31c, the electrode 13c is connected to the signal ground potential, and current is passed from the electrode 13b to the electrode 13c.

(When driven by the constant voltage drive method)
When the Hall element 2 in which the electrodes 13a to 13c are arranged in three-fold rotational symmetry as shown in FIG. 13 is driven by the constant voltage driving method shown in FIG. It can be represented by the equivalent circuit shown in (a).
When no magnetic field is applied to the magnetic field sensing portion 12, approximately the same current flows from the electrode serving as the drive terminal T1 to the output terminals T2 and T3. Therefore, the output current difference between the output terminal T2 and the output terminal T3 becomes substantially zero, and the resistance r12 in the conductive path from the drive terminal T1 to the output terminal T2 caused by the slight asymmetry of the magnetic sensing part 12 and the output from the drive terminal T1 Only the current difference corresponding to the difference with the resistance r31 in the conduction path to the terminal T3, that is, the offset component Iu, is the output current difference between the output terminals T2 and T3. When a magnetic field is applied, a difference corresponding to the applied magnetic field occurs between the resistor r12 and the resistor r23, and the output current difference between the output terminal T2 and the output terminal T3 causes the resistor r12 and the resistor r23 A current difference of the magnetoelectric conversion component Ih appears according to the resistance difference between . A current difference I23 between the output terminals T2 and T3 when a magnetic field is applied can be expressed by the following equation (13).
I23=I2-I3=Iu+Ih (13)

Next, as shown in FIG. 13(b), by applying a constant voltage Vc to the output terminal T2 and connecting the output terminal T3 to the signal ground potential, a constant voltage is applied between the output terminal T2 and the output terminal T3. Apply Vc. That is, the voltage applied to the resistor r12 is opposite to that shown in FIG. 13(a). Also, a voltage source that outputs a constant voltage Vc/2 is connected, and a current detector detects the current flowing through the path passing through the drive terminal T1 and this constant voltage source. In FIG. 13B, a constant voltage Vc is applied across the resistor r23, and a constant voltage Vc is applied across the serially connected resistors r12 and r31. When no magnetic field is applied to the magnetism sensing section 12, the resistors r12 and r31 are substantially the same, and the current flowing through the path passing through the drive terminal T1 and the voltage source that outputs the constant voltage Vc/2 is substantially zero. becomes. In other words, a current equivalent to half of the offset component Iu corresponding to the resistance difference between the resistors r12 and r31 caused by the slight asymmetry of the magnetic field sensing portion 12 is applied to the drive terminal T1 and the voltage source that outputs the constant voltage Vc/2. Flow through the route. This current is detected by a current detector. When a magnetic field is applied, a difference corresponding to the applied magnetic field occurs between the resistors r12 and r31, and a current corresponding to half of the magnetoelectric conversion component Ih corresponding to the resistance difference flows through the drive terminal T1. , which is detected by the current detector as a current value whose sign is inverted.

A current I'23 flowing through the path passing through the drive terminal T1 and the voltage source outputting the constant voltage Vc/2 when the magnetic field is applied can be expressed by the following equation (14).
I′23=(Iu−Ih)/2 (14)
Therefore, from "I23" (current difference between output terminals T2 and T3) detected in the equivalent circuit shown in FIG. 13(a), "I'23" (drive terminal T1 (the current flowing through T1) is doubled and subtracted to obtain a differential signal Si can be obtained.

In each connection pattern according to the above-described procedure, the difference signal Si, which does not include the offset component of the Hall element 2 and is composed of the current difference between the output terminals T2 and T3, is obtained. A magnetic field strength can be obtained that is less affected by the offset component of 2.
Specifically, an equivalent circuit shown in FIG. 13A is formed for each of the three connection patterns, and a signal "I23" containing the offset component Iu and the magnetoelectric conversion component Ih is generated from the current difference between the output terminals T2 and T3. and an operation of forming the equivalent circuit shown in FIG. 13(b) to obtain a signal "I'23" containing the offset component Iu and the sign-inverted magnetoelectric conversion component Vh by means of the current detector. That is, when obtaining the differential signal Si corresponding to the three connection patterns, predetermined signals are obtained in two phases for each connection pattern, for a total of six phases.

The process of obtaining the difference signal Si from which the offset voltage is removed is also performed in the output unit 24, for example. 13A and FIG. 13B are formed by the switch unit 21, for example.
Thus, the magnetic sensor 1 according to one embodiment of the present invention can detect the magnetic field strength in three axial directions by providing the three electrodes 13a to 13c in one Hall element 2, and By adjusting the aspect ratio, the sensitivity can be oriented in the direction in which the change in the magnetic field is large, and a signal with a high S/N ratio can be obtained. Therefore, it is possible to obtain high S/N magnetic field strength in the triaxial directions with a smaller number of terminals than in the prior art.

When the magnetic sensor 1 according to the embodiment shown in FIG. 1 has four or more electrodes, three electrodes forming a triangle are selected from among the four or more electrodes, and any one of the electrodes are used as drive terminals, and the other two electrodes are used as output terminals, and for the three electrodes forming the triangle, the connection destinations are switched as described in the above embodiment to acquire at least three differential signals Si with different connection patterns. You should do it. Here, one triangle may be selected and at least three difference signals Si may be obtained from the triangle, or a plurality of triangles may be selected and at least three difference signals Si may be obtained from these triangles.

Further, in the above-described embodiment, in the magnetic sensor 1 having the three electrodes 13a to 13c, the differential signal Si is obtained for a total of three connection patterns once for each connection pattern. A plurality of differential signals Si are acquired for each of the three connection patterns for a plurality of times in the connection pattern, and based on the acquired plurality of differential signals Si, for example, by using an average of the differential signals Si of the same connection pattern, the three An axial magnetic field measurement signal may be obtained.

Further, even when four or more electrodes are provided, the difference signal Si is obtained with three or more connection patterns with different combinations, and the difference signals Si obtained with three connection patterns with different combinations are used as described above. The triaxial magnetic field measurement signal may be obtained by the same procedure, or the triaxial magnetic field measurement signal may be obtained using all the differential signals Si obtained with all connection patterns in different combinations. . Furthermore, also in this case, the differential signal Si may be acquired once for each connection pattern, and the three-axis measurement signal may be acquired using a plurality of differential signals Si, one acquired for each connection pattern, Alternatively, the triaxial magnetic field measurement signal may be obtained by obtaining the difference signal Si multiple times for each connection pattern and, for example, using the average of the difference signals Si for the same connection pattern.

In either case, the triaxial magnetic field measurement signal can be acquired by switching the connection destination so that the matrix M composed of the sensitivity vectors Mi has a general inverse matrix M ^† .
Further, in the above embodiment, the case where magnetic field components in three axial directions are acquired has been described, but the present invention is not limited to this, and only magnetic field components in one axial direction may be acquired.
Although the embodiments of the present invention have been described above, the above embodiments illustrate devices and methods for embodying the technical idea of the present invention. It does not specify the material, shape, structure, arrangement, etc. Various modifications can be made to the technical idea of the present invention within the technical scope defined by the claims.

1 Magnetic sensor 2 Hall element 3 Signal processing unit 11 Substrate 12 Magnetic sensing units 13a to 13c Electrode 21 Switch unit 22 Driving unit 23a, 23b Detecting unit 24 Output unit 25 Arithmetic processing unit

Claims (8)

a magnetic sensing portion formed on one surface of the substrate and having a predetermined thickness to be sensitive to both the perpendicular magnetic field and the in-plane magnetic field ;
a plurality of electrodes arranged to form at least one triangle on the upper surface of the magnetic field sensing portion;
a drive unit connected to one of the electrodes and configured to drive the magnetic sensing unit;
a calculation unit having a plurality of connection terminals;
a switch unit that switches the plurality of electrodes according to a plurality of connection patterns and connects them to the driving unit and the connection terminal;
with
An aspect ratio of the magnetic sensing portion (the predetermined thickness of the magnetic sensing portion/minimum distance between the plurality of electrodes) is 0.01 or more and 1 or less, and each of the connection patterns is set and stored to be sensitive to both magnetic field components in directions perpendicular to a plane containing the three electrodes forming said triangle and magnetic field components in directions parallel to said plane;
The connection patterns comprise three connection patterns for each triangle, a first connection pattern of the three connection patterns being a first electrode of the three electrodes forming the triangle. and the drive unit, and a second electrode and a third electrode of the three electrodes are connected to the plurality of connection terminals, respectively, and the third of the three connection patterns The second connection pattern is a pattern in which the second electrode and the drive section are connected, and the first electrode and the third electrode are each connected to the plurality of connection terminals, and the three A third connection pattern among the connection patterns is a pattern in which the third electrode and the drive section are connected, and the first electrode and the second electrode are each connected to the plurality of connection terminals. and
The calculation unit has a preset calculation formula for calculating magnetic field components in triaxial directions representing the magnitude of the magnetic field applied to the magnetic field sensing unit based on a triaxial magnetic field calculation matrix,
The arithmetic expression is such that the drive unit inputs a constant current or a constant voltage to the electrodes connected to the drive unit for each of the three connection patterns, applies a known magnetic field to the magnetic sensing unit, A set of output signals from the plurality of connection terminals is obtained for each of the connection patterns when a conductive path is formed in the magnetic sensing portion by being driven by the unit, and the output signal set is calculated for each set of output signals. At least three differential signals indicating a potential difference or a current difference between the two connection terminals, or a constant current or constant voltage input to the electrode connected to the drive unit for each of the three connection patterns by the drive unit. and the electrode connected to the drive section and the other one of the electrodes obtained by dividing the potential difference between the electrode connected to the drive section and one of the connection terminals when no magnetic field is applied. A difference between a known potential difference, which is a potential difference between connection terminals, and a potential difference between the electrode connected to the drive section and the other connection terminal when a known magnetic field is applied to the magnetic sensing section. based on at least three differential signals and triaxial magnetic field components representing the magnitude of the known magnetic field, preset according to an acquisition method when the three differential signals are acquired,
The computing section outputs signals from the plurality of connection terminals when a magnetic field to be detected is applied to the magnetic field sensing section and is driven by the driving section to form a conductive path in the magnetic field sensing section. are acquired for each of the connection patterns, and at least three difference signals indicating the potential difference or current difference between the two connection terminals calculated for each of the output signal sets, or the known potential difference and the sensor. at least three difference signals indicating the difference between the potential difference between the electrode connected to the drive unit and the other connection terminal when the magnetic field to be detected is applied to the magnetic unit; A magnetic sensor that calculates magnetic field components in the three axial directions of the magnetic field to be detected applied to the magnetic sensing part from the arithmetic expression corresponding to the acquisition method when the signal is acquired, and outputs the magnetic field as a magnetic signal. a magnetic sensing portion formed on one surface of the substrate and having a predetermined thickness to be sensitive to both the perpendicular magnetic field and the in-plane magnetic field ;
a plurality of electrodes arranged to form a plurality of triangles on the upper surface of the magnetic field sensing portion;
a drive unit connected to one of the electrodes and configured to drive the magnetic sensing unit;
a calculation unit having a plurality of connection terminals;
a switch unit that switches the plurality of electrodes in a plurality of connection patterns and connects them to the driving unit and the connection terminal;
An aspect ratio of the magnetic sensing portion (the predetermined thickness of the magnetic sensing portion/minimum distance between the plurality of electrodes) is 0.01 or more and 1 or less, and each of the connection patterns is set and stored to be sensitive to both magnetic field components in directions perpendicular to a plane containing the three electrodes forming said triangle and magnetic field components in directions parallel to said plane;
The connection pattern includes a connection pattern that connects one electrode of three electrodes forming one triangle to the drive unit and connects the other two electrodes to the connection terminal, respectively, using the same or different triangles. At least 3 patterns are included as targets,
The calculation unit has a preset calculation formula for calculating magnetic field components in triaxial directions representing the magnitude of the magnetic field applied to the magnetic field sensing unit based on a triaxial magnetic field calculation matrix,
The arithmetic expression is such that the drive unit inputs a constant current or a constant voltage to the electrodes connected to the drive unit for each of the three connection patterns, applies a known magnetic field to the magnetic sensing unit, A set of output signals from the plurality of connection terminals is obtained for each of the connection patterns when a conductive path is formed in the magnetic sensing portion by being driven by the unit, and the output signal set is calculated for each set of output signals. At least three differential signals indicating a potential difference or a current difference between the two connection terminals, or a constant current or constant voltage input to the electrode connected to the drive unit for each of the three connection patterns by the drive unit. and the electrode connected to the drive section and the other one of the electrodes obtained by dividing the potential difference between the electrode connected to the drive section and one of the connection terminals when no magnetic field is applied. A difference between a known potential difference, which is a potential difference between connection terminals, and a potential difference between the electrode connected to the drive section and the other connection terminal when a known magnetic field is applied to the magnetic sensing section. based on at least three differential signals and triaxial magnetic field components representing the magnitude of the known magnetic field, preset according to an acquisition method when the three differential signals are acquired,
The computing section outputs signals from the plurality of connection terminals when a magnetic field to be detected is applied to the magnetic field sensing section and is driven by the driving section to form a conductive path in the magnetic field sensing section. are acquired for each of the connection patterns, and at least three difference signals indicating the potential difference or current difference between the two connection terminals calculated for each of the output signal sets, or the known potential difference and the sensor. at least three difference signals indicating the difference between the potential difference between the electrode connected to the drive unit and the other connection terminal when the magnetic field to be detected is applied to the magnetic unit; A magnetic sensor that calculates magnetic field components in the three axial directions of the magnetic field to be detected applied to the magnetic sensing part from the arithmetic expression corresponding to the acquisition method when the signal is acquired, and outputs the magnetic field as a magnetic signal. 2. The magnetic sensor according to claim 1, wherein said magnetic field sensing portion comprises three said electrodes, and said electrodes are arranged to form an equilateral triangle. the plurality of electrodes are arranged so as to form at least one isosceles triangle on the magnetically sensitive portion;
3. The magnetic sensor according to claim 1, wherein the connection pattern is set and stored for the electrodes forming the isosceles triangle. wherein the plurality of electrodes are arranged such that at least two isosceles triangles are formed in the magnetically sensitive portion;
3. The magnetic sensor according to claim 1, wherein the connection pattern is set and stored for the electrodes forming the isosceles triangle. wherein the plurality of electrodes are arranged such that at least three isosceles triangles are formed in the magnetically sensitive portion;
3. The magnetic sensor according to claim 1, wherein the connection pattern is set and stored for the electrodes forming the isosceles triangle. The magnetic sensor according to any one of claims 4 to 6, wherein the plurality of electrodes are arranged at positions that are rotationally symmetrical in plan view. 8. The magnetic sensor according to any one of claims 4 to 7, wherein the magnetic sensing section includes the four electrodes.

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