Magnetic sensor device

Abstract

Magnetic sensor device, comprising: a magnetic field generator for generating a magnetic field that intersects a detection object (50); and a plurality of sets of magnetoresistive elements arranged in a line in a longitudinal direction, wherein the longitudinal direction is perpendicular to a direction of movement of the detection object (50), wherein Each of the plurality of sets of magnetoresistive elements contains a first resistor (31a) and a second resistor (31b) arranged with a distance between them in the direction of motion, wherein a center point of the first resistor and the second resistor is adapted to a center of the magnetic field generator in the direction of motion, the magnetic field generator applies a magnetic field to a plurality of the first resistors (31a) and a plurality of the second resistors (31b), which contains a component in the direction of movement of the detection object and a component in the longitudinal direction, the first resistor (31a) and the second resistor (31b) in each of the plurality of sets of magnetoresistive elements are arranged such that the distance increases from a distance between first ends of the first resistor (31a) and the second resistor (31b) in the longitudinal direction to a distance between second ends of the first resistor (31a) and the second resistor (31b) in the longitudinal direction, and at least two sets of the first resistor (31a) and the second resistor (31b) are arranged such that they are axially symmetric with respect to an axis of the magnetic field generator which runs perpendicular to the longitudinal direction, a first group (A) of the plurality of sets of magnetoresistive elements is arranged on a first side, in the longitudinal direction, of a central axis (Cy) of the magnetic field generator in the longitudinal direction, wherein the central axis (Cy) intersects a center, in the longitudinal direction, of the magnetic field generator and is perpendicular to the longitudinal direction, a second group (B) of the plurality of sets of magnetoresistive elements is arranged on a second side, in the longitudinal direction, of the central axis (Cy), in each set of magnetoresistive elements in the first group (A) the first ends of the first resistor (31a) and the second resistor (31b) are closer to the central axis (Cx) than the second ends of the first resistor (31a) and the second resistor (31b), and In all but one set of magnetoresistive elements in the second group (B), the first ends of the first resistor (31a) and the second resistor (31b) are closer to the central axis (Cx) than the second ends of the first resistor (31a) and the second resistor (31b).

Description

Technical field

[0001] The present disclosure relates to a magnetic sensor device. State of the art

[0002] A known magnetic sensor device contains several magnetoresistive elements with resistances that change according to the magnetic flux density. For example, a magnetic sensor device described in JP 6 316 429 B contains several magnetoresistive elements to detect a magnetic pattern on a paper sheet medium such as a banknote using multiple channels.

[0003] To improve detection sensitivity, the magnetic sensor device described in JP 6 316 429 contains two magnetoresistive elements arranged side by side in a bridge circuit in the transport direction (hereinafter X-direction).

[0004] Disclosing a magnetic sensor device, it comprises a magnetic field generator arranged on a surface of a planar measuring object, which has a magnetic component to generate a crossing magnetic field that intersects the measuring object, and a magnetoresistive element arranged between the measuring object and the magnetic field generator. The magnetoresistive element has a resistance that changes relative to a change in a component of the crossing magnetic field in a conveying direction along which the measuring object is conveyed, the change occurring as the measuring object is conveyed in that direction. The magnetoresistive element has resistive elements arranged side-by-side in the conveying direction and connected to each other via a bridge. The resistive elements are arranged axially symmetrically about an axis perpendicular to the conveying direction and extend through a center point of the bridge.A position in the conveying direction of the center of the bridge of the element with magnetoresistive effect corresponds to a position in the conveying direction of the center of the magnetic field generator.

[0005] US 2015 / 0 369 882 A1 discloses a device for detecting magnetic substances using elongated magnets and ferromagnetic thin-film resistive elements. The magnets extend parallel to a Y-axis direction and are magnetized oppositely in a Z-axis direction. The ferromagnetic thin-film resistive elements each have linear segments that extend substantially along the Y-axis direction in a plane of a substrate arranged in a path of magnetic field lines between the magnets, and change their resistance in response to a change in a magnetic field directed orthogonally to the Y-axis direction in the plane of the substrate.The magnets apply bias magnetic fields to the ferromagnetic thin-film magnetic resistance elements in a direction orthogonal to the Y-axis direction in the plane of the substrate, the intensity of which is lower than a saturation magnetic field of the ferromagnetic thin-film magnetic resistance elements.

[0006] DE 103 42 260 A1 discloses magnetoresistive sensors based on the AMR or GMR effect, which exhibit significantly extended linear characteristic curves because their resistors are composed of magnetoresistive strips of different shape anisotropy. Different shape anisotropies can be achieved by varying strip widths, strip thicknesses, strip spacing, or strip materials. Temperature compensation for the output voltage of the magnetoresistive sensors at at least one point on the characteristic curve is achieved by connecting another strip of material with a different temperature coefficient relative to the magnetoresistive material in series with at least one magnetoresistive resistor of the sensor. Summary of the invention: Technical problem

[0007] A magnetoresistive element has an applied magnetic flux resistance characteristic that exhibits hysteresis. After reading a paper substrate, two magnetoresistive elements connected by a bridge may be affected differently by this hysteresis. These differing hysteresis characteristics can also affect the voltage division ratio, potentially leading to an unstable output signal.

[0008] In response to the above problem, the Fig. The technique described in JP 6 316 429 involves positioning each pair of magnetoresistive elements with a larger distance between them from end to end in the direction of the reading width. This structure can apply a stable bias field in the longitudinal direction of the magnetoresistive elements, i.e., in the non-magnetosensitive direction, using a magnetic field applied by a permanent magnet in the X-direction, thus reducing the resistance changes caused by such hysteresis. The magnetoresistive elements can therefore provide stable performance.

[0009] In a region where a bias field By in the Y-direction is negative, a component of the bias field By in the Y-direction along the longitudinal direction of the magnetoresistive elements and a component of a bias field Bx in the X-direction along the longitudinal direction of the magnetoresistive elements cancel each other out. As a result, the magnetoresistive elements acquire a weaker, longitudinally applied magnetic field and are less likely to generate a stable output signal.

[0010] In response to the above problem, the structure described in JP 6 300 908 B incorporates a micromagnet at one end of a longitudinally oriented magnet to force a magnetic field in the same direction as the non-magnetic direction of each anisotropic magnetoresistive element arranged in the line. However, the structure in JP 6 300 908 B can complicate the construction of the magnet that applies a premagnetizing field.

[0011] In response to the above problem, the object of the present invention is to arrange a magnetic sensor device with a simple structure that can provide a stable output. Solution to the problem

[0012] This problem is solved by a magnetic sensor device with the features according to claims 1 and 5. Advantageous embodiments of the magnetic sensor device with the features according to claim 1 are set out in claims 2 to 4. Advantageous effects of the invention

[0013] According to the magnetic sensor device as described above in the present disclosure, at least two sets of the first resistor and the second resistor are arranged axially symmetrically with respect to the axis of the magnetic field generator, which is perpendicular to the longitudinal direction. The component of the magnetic field in the direction of motion and the component of the magnetic field in the longitudinal direction can thus be added to form a magnetic field applied in the longitudinal direction of each resistor, regardless of the orientation of the component of the magnetic field applied in the longitudinal direction by the magnetic field generator. The magnetic sensor device, with its simple structure, can therefore apply the magnetic field in the longitudinal directions of the resistors stably, is less susceptible to hysteresis, and provides a stable output. Brief description of the drawings Fig. Figure 1 is a cross-sectional view of a magnetic sensor device according to an embodiment of the present invention parallel to a direction of movement of a detection object, taken along line II in Fig. 2; Fig. Figure 2 is a cross-sectional view of the magnetic sensor device according to the embodiment in an insertion and ejection direction of the detection object, taken along line II-II in Fig. 1; Fig. Figure 3A is a schematic diagram of an anisotropic magnetoresistive element (AMR) chip according to the embodiment, which includes a layout of several pairs of magnetoresistive elements; Fig. Figure 3B is a circuit diagram of the AMR chip in its embodiment; Fig. Figure 4 is a diagram showing the distribution of a magnetic field generated by a magnet in the embodiment; Fig. Figure 5 is a diagram showing the distribution of a premagnetization field By in the Y direction, applied to the magnetoresistive elements in Fig. 1 is created; Fig. 6A is a diagram representing a component of a magnetic field applied to one of the Fig. 3A shows magnetoresistive elements arranged in the longitudinal direction; Fig. 6B is a diagram that represents the component of the magnetic field at one of the in Fig. 3A shows magnetoresistive elements arranged in the longitudinal direction; Fig. 6C is a diagram that represents the component of the magnetic field at one of the in Fig. 3A shows magnetoresistive elements arranged in the longitudinal direction; Fig. Figure 7 is a top view of an AMR chip contained in a magnetic sensor device according to another embodiment 1; Fig. Figure 8 is a diagram showing the relationship between the positions of the magnetoresistive elements in the Fig. 7 shows the AMR chip in the Y direction and the strength of the magnetic field applied in the longitudinal directions of the magnetoresistive elements; Fig. 9 is a diagram showing the relationship between the positions of the magnetoresistive elements in the Fig. 7 shows the AMR chip in the Y direction and the sensitivity of the magnetoresistive elements; Fig. Figure 10A is a top view of an AMR chip contained in a magnetic sensor device according to another embodiment 2; Fig. 10B is a diagram showing the orientations of the Fig. 10A represents the magnetoresistive elements shown; Fig. 10C is a diagram showing the relationship between the positions of the magnetoresistive elements in the Fig. Figure 10A shows the AMR chip in the Y direction and the sensitivity of the magnetoresistive elements; and Fig. Figure 11 is a top view of an AMR chip contained in a magnetic sensor device according to another embodiment 3. Description of the embodiments

[0014] A magnetic sensor device according to an embodiment of the present invention is described.

[0015] In the following, the direction of movement of a recognition object, i.e., the transverse direction of the magnetic sensor device, is defined as the X-direction; the longitudinal direction of the magnetic sensor device perpendicular to the direction of movement of the recognition object, i.e., the reading width direction, is defined as the Y-direction; and the direction perpendicular to an XY plane, which is a transport surface, is defined as the Z-direction. Appropriate reference will be made to these directions. embodiment of the present invention

[0016] Fig. Figure 1 is a ZX cross-sectional view of a magnetic sensor device 100 according to the embodiment of the invention. Fig. Figure 2 is a YZ cross-sectional view of the magnetic sensor device 100. Fig. Figure 3 is a top view of a chip with an anisotropic magnetoresistive element contained in the magnetic sensor device 100. Fig. 1 corresponds to a cross-section along line II in Fig. 2. Fig. 2 corresponds to a cross-section along line II-II in Fig. 1.

[0017] As shown, the magnetic sensor device 100 includes a magnet 1 for generating a premagnetization field, yokes 2a and 2b forming a magnetic circuit, a chip 3 with an anisotropic magnetoresistive element for outputting a change in the magnetic field as a change in resistance, a housing 4 that accommodates the magnet 1 and the yokes 2a and 2b, a metallic shielding plate 5 as a shield against magnetism, a circuit board 6 for detecting a change in resistance of a magnetoresistive element, and a signal processing circuit board 7 for processing a detection signal output by the circuit board 6.

[0018] Magnet 1 contains a permanent magnet with a north pole and a south pole in the Z direction, which has the shape of a rectangular parallelepiped that is long in the Y direction and short in the X direction. Magnet 1 forms a magnetic field generation unit that applies a premagnetizing field to chip 3 with an anisotropic magnetoresistive element.

[0019] The yokes 2a and 2b are soft magnetic plates, such as iron plates. Yoke 2a is located on the upper surface of magnet 1. Yoke 2b is located on the underside of magnet 1. The yokes 2a and 2b transmit a magnetic flux generated by magnet 1. The yokes 2a and 2b are part of the magnetic field generation unit. The yokes 2a and 2b can be omitted or arranged in a suitable manner.

[0020] The chip 3 with anisotropic magnetoresistive element (hereinafter referred to as AMR chip 3) is located on the top side of the yoke 2a and outputs a change in the applied magnetic flux as a change in resistance. The AMR chip 3 will be described in detail later.

[0021] Housing 4 is made of a resin or a ceramic material. Housing 4 is a box with an opening in its upper surface and accommodates magnet 1 and yokes 2a and 2b.

[0022] The metallic shielding plate 5 covers and protects the circuit board 6 and the surface of the AMR chip 3 facing the path of movement of a detection object 50. The metallic shielding plate 5 is not magnetized and does not transmit magnetic field lines.

[0023] The circuit board 6 is located on the top of the yoke 2a and surrounds the AMR chip 3. The circuit board 6 applies a supply voltage VDD and a ground voltage GND to the AMR chip 3 and outputs detection signals that indicate changes in the resistance of the magnetoresistive elements.

[0024] The signal processing circuit board 7 is located under the housing 4 and is connected to the circuit board 6 via a cable 8. The signal processing circuit board 7 processes the recognition signals to recognize the recognition object 50.

[0025] The recognition object 50 is a sheet-shaped object, e.g., a banknote, printed with a magnetic material, e.g., magnetic ink. The recognition object 50 is transported in the positive X direction.

[0026] The AMR chip 3 is described with reference to Fig. 3 described in detail.

[0027] The AMR chip 3 contains eight pairs of anisotropic magnetoresistive elements 31a and anisotropic magnetoresistive elements 31b. The anisotropic magnetoresistive elements 31a and 31b in each pair are arranged on imaginary lines and are axially symmetric with respect to a central axis Cx, which passes through the center of the AMR chip 3 in the X direction and extends in the Y direction, i.e., in the longitudinal direction of the AMR chip 3.

[0028] The anisotropic magnetoresistive elements 31a and 31b each have long sides and short sides in a top view. The short sides extend in a magnetosensitive direction. The long sides extend in a non-magnetosensitive direction.

[0029] Each anisotropic magnetoresistive element 31a is an example of a first resistor. Each anisotropic magnetoresistive element 31b is an example of a second resistor. The anisotropic magnetoresistive elements 31a and 31b in each pair are arranged such that the central axis Cx coincides longitudinally with the center of the magnetic field generator, which contains the magnet 1 and the yokes 2a and 2b, in the X-direction. The anisotropic magnetoresistive elements 31a and 31b are axially symmetric with respect to the central axis Cx in the longitudinal direction.

[0030] The anisotropic magnetoresistive elements 31a and 31b are spaced apart at a distance that increases or decreases in the Y-direction. At least two sets of the anisotropic magnetoresistive elements 31a and 31b are arranged such that they are axially symmetric with respect to a central axis Cy of the magnetic field generator, which contains the magnet 1 and the yokes 2a and 2b, in the Y-direction. The central axis Cy passes through the center of the AMR chip 3 in the Y-direction and extends in the X-direction, i.e., transversely to the AMR chip 3.

[0031] More precisely, the region in the positive Y-direction from an imaginary line Cy' perpendicular to the longitudinal direction of magnet 1 contains five pairs, or five sets, of the anisotropic magnetoresistive elements 31a and 31b, arranged such that their distance from each other increases as the value of Y increases. The region in the negative Y-direction from the imaginary line Cy' contains three pairs, or three sets, of the anisotropic magnetoresistive elements 31a and 31b, arranged such that their distance from each other increases as the value of Y increases. This results in the three sets of anisotropic magnetoresistive elements 31a and 31b in each region, and a total of six sets, being axially symmetric with respect to the central axis Cy in the Y-direction. The five sets of anisotropic magnetoresistive elements 31a and 31b are contained in a group A.The distance between the anisotropic magnetoresistive elements 31a and 31b in each set in group A increases with increasing value Y. The three sets of anisotropic magnetoresistive elements 31a and 31b are contained in a group B. The distance between the anisotropic magnetoresistive elements 31a and 31b in each set in group B decreases as the value Y increases. Furthermore, the anisotropic magnetoresistive elements 31a in the five sets in group A and in the three sets in group B, and the anisotropic magnetoresistive elements 31b in the five sets in group A and in the three sets in group B, are axially symmetric with respect to the central axis Cx in the Y direction.

[0032] As in Fig. As shown in Figure 3B, the printed circuit board 6 applies the power supply voltage VDD to a first end of each anisotropic magnetoresistive element 31a. The printed circuit board 6 applies the ground voltage GND to a first end of each anisotropic magnetoresistive element 31b. The anisotropic magnetoresistive element 31a and the anisotropic magnetoresistive element 31b in each pair have second ends that are short-circuited, from which an output signal from each pair is output to the printed circuit board 6 via an output signal line.

[0033] In this structure, the supply voltage VDD is divided by the ratio between the resistance of the anisotropic magnetoresistive element 31a and the resistance of the anisotropic magnetoresistive element 31b and output as a detection signal to the output signal line.

[0034] As the detection object 50, which contains a magnetic material, moves along the path of travel, the magnetic field applied to each of the anisotropic magnetoresistive elements 31a and 31b changes. The resistances of the anisotropic magnetoresistive elements 31a and 31b change accordingly, thereby changing the voltage division ratio of each pair and the voltages of the detection signals. The circuit board 6 transmits the detection signals to the signal processing circuit board 7. The signal processing circuit board 7 processes the detection signals to detect the detection object 50.

[0035] The construction of the above magnetic sensor device 100 for applying a premagnetization field to the anisotropic magnetoresistive elements 31a and 31b is described.

[0036] Fig. Figure 4 is a diagram showing the distribution of magnetic field lines emitted by the magnetic field generating unit, which contains magnet 1 and yokes 2a and 2b. Fig. Figure 4 shows the components relevant for the distribution of the magnetic field lines, and the other components are not shown. As in Fig. As shown in Figure 4, the magnetic field lines 20 emanating from the north pole of magnet 1 pass through yoke 2a in an XZ plane and exit the XY and YZ planes of yoke 2a outside of magnet 1 and yoke 2a. The magnetic field lines 20 from magnet 1 and yoke 2a enter yoke 2b at the south pole of magnet 1 through the XY and YZ planes of yoke 2b. The magnetic field lines 20 entering yoke 2b converge at the south pole of magnet 1 through yoke 2b.

[0037] The central axis of the AMR chip 3 in the X-direction, i.e., the central axis Cx in the longitudinal direction, lies at the midpoint of magnet 1 and yoke 2a in the X-direction. Similarly, the central axis in the Y-direction, perpendicular to the longitudinal direction of the AMR chip 3, i.e., the central axis Cy, lies at the midpoint of magnet 1 and yoke 2a in the Y-direction.

[0038] Thus, a positive component Bx of the magnetic field indicated by the magnetic field lines 20 in the X-direction acts as a premagnetizing field in the X-direction for the anisotropic magnetoresistive elements 31a. Conversely, a negative component Bx in the negative X-direction acts as a premagnetizing field in the X-direction for the anisotropic magnetoresistive elements 31b. This relationship is shown in the Fig. 3A and Fig. Figure 4 illustrates this. This premagnetization field enables stable application of a magnetic field in the longitudinal directions of the anisotropic magnetoresistive elements 31a and 31b. This reduces the hysteresis of the anisotropic magnetoresistive elements 31a and 31b. The anisotropic magnetoresistive elements 31a and 31b can thus have a stable output.

[0039] The AMR chip 3 and the magnet 1 are longer in the Y direction than in the X direction. Therefore, a magnetic field applied in the Y direction essentially has the same effect as in Fig. The intensity distribution shown in section 5 is shown. More precisely, the top view shows... Fig. 3A A magnetic field in the positive Y-direction is theoretically applied in the area in the positive Y-direction, i.e., the right-hand area, from the central axis Cy. A magnetic field in the negative Y-direction is applied in the area in the negative Y-direction, i.e., in the left-hand area, from the central axis Cy. However, a premagnetization field By in the Y-direction can be applied in the central area, i.e., within area (a) in Fig. 5, can be considered almost zero.

[0040] The arrangement in area (b) in Fig. 5, which corresponds to the end in the positive Y direction from the central axis Cy, i.e., the area at the right end of the drawing, is described. As in Fig. As shown in Figure 6A, the magnetic field applied in the longitudinal direction of the anisotropic magnetoresistive element 31a is the sum of a component / / Bx of the premagnetization field Bx in the X-direction along the longitudinal direction of the anisotropic magnetoresistive element 31a and a component / / By of the premagnetization field By in the Y-direction along the longitudinal direction of the anisotropic magnetoresistive element 31a. The premagnetization field in the longitudinal direction of the anisotropic magnetoresistive element 31a is thus stably supplied by both the premagnetization field Bx in the X-direction and the premagnetization field By in the Y-direction.

[0041] The arrangement in area (c) in Fig. 5, which corresponds to the end in the negative Y direction from the central axis Cy, i.e., the left end of the drawing, is described. As in Fig. As shown in Figure 6B, the bias field By in the Y direction lies in the negative Y direction. In contrast, the bias field Bx in the X direction is the same as in Figure 6B. Fig. 6A. In the following example, the anisotropic magnetoresistive elements 31a and 31b have a greater distance between them in region (c) as the value Y increases. In this example, the component / / Bx of the bias field Bx in the X-direction lies along the longitudinal direction of the anisotropic magnetoresistive element 31a, and the component / / By of the bias field By in the Y-direction lies along the longitudinal direction of the anisotropic magnetoresistive element 31a in opposite directions, so that they cancel each other out in the magnetic field applied along the longitudinal direction of the anisotropic magnetoresistive element 31a. The bias field in the longitudinal direction is thus the difference between the component / / Bx and the component / / By. The anisotropic magnetoresistive element 31a receives a small bias field in the longitudinal direction and is therefore likely to be affected by hysteresis.

[0042] In the structure in Fig. 3A contains the area in the negative Y direction from the imaginary line Cy' perpendicular to the longitudinal direction of the magnet 1 the three sets of anisotropic magnetoresistive elements 31a and 31b, which are arranged such that they have a smaller distance from each other as the value Y increases.

[0043] In this case, as in Fig. As shown in Figure 6C, one component of the magnetic field applied in the longitudinal direction of the anisotropic magnetoresistive element 31a is the sum of the component / / Bx of the premagnetization field Bx in the X-direction in the longitudinal direction of the anisotropic magnetoresistive element 31a and the component / / By of the premagnetization field By in the Y-direction in the longitudinal direction of the anisotropic magnetoresistive element 31a, where Bx is the premagnetization field in the X-direction and By is the premagnetization field in the negative Y-direction. The premagnetization field in the longitudinal direction of the anisotropic magnetoresistive element 31a is thus stabilized by both the premagnetization field Bx in the X-direction and the premagnetization field By in the Y-direction in the anisotropic magnetoresistive elements 31a and 31b in region (c). Fig. 5 were supplied, arranged so that they have a smaller distance between them as the value Y increases.

[0044] In the present embodiment, as described above, at least more than one pair of the anisotropic magnetoresistive elements 31a and 31b in the end regions of the magnet, where the direction of the premagnetization field By in the Y-direction is positive or negative, receive the premagnetization field in the longitudinal directions of the anisotropic magnetoresistive elements 31a and 31b, which is the sum of the premagnetization field Bx in the X-direction and the premagnetization field By in the Y-direction. This structure enables a more stable output over a wider area, particularly near the ends, than that described above. Fig. 9 in JP 6 316 429 arrangement in which the distance between the anisotropic magnetoresistive element 31a and the anisotropic magnetoresistive element 31b increases in the same direction in all pairs.

[0045] Furthermore, the magnetic sensor device 100 according to the present embodiment has a more uniform sensitivity distribution and thus a more uniform signal distribution. Alternative design 1

[0046] In the embodiment of the invention, at least two sets, or more precisely six sets, which are six pairs, of the anisotropic magnetoresistive element 31a and the anisotropic magnetoresistive element 31b are axially symmetric with respect to the central axis Cy. However, the structure is not limited to this. At least two sets of the anisotropic magnetoresistive element 31a and the anisotropic magnetoresistive element 31b can simply be axially symmetric with respect to the central axis Cy. For example, as in Fig. Figure 7 shows that all four sets of anisotropic magnetoresistive elements 31a and 31b in the region in the positive Y direction from the central axis Cy, and all four sets of anisotropic magnetoresistive elements 31a and 31b in the region in the negative Y direction from the central axis Cy, totaling eight sets, are axially symmetric with respect to the central axis Cy. Due to the axially symmetric arrangement of pairs of anisotropic magnetoresistive elements 31a and 31b, the fabrication of multiple types of AMR chips 3 is unnecessary; only a single original prototype is required, prepared for the anisotropic magnetoresistive elements 31a and 31b on the AMR chip 3. This structure is less expensive.

[0047] In this case, as in Fig. Figure 8 shows that the premagnetization field B / / in the longitudinal direction of each of the anisotropic magnetoresistive elements 31a and 31b is essentially uniform at every position in the Y-direction. As shown in Fig. As shown in Figure 9, the sensitivity at each position in the Y direction is also essentially uniform. Other embodiment of the invention

[0048] A magnetic sensor device 100 according to another embodiment of the invention is described with reference to Fig. 10 described. In Fig. 10 are components that are equal to or equivalent to those in Fig. The components shown in Figure 3A are provided with the same reference numerals, and the explanation of such components is omitted.

[0049] Fig. Figure 10A is a top view of an AMR chip 3 contained in the magnetic sensor 100 according to another embodiment of the invention. In this structure, the anisotropic magnetoresistive elements 31a and the anisotropic magnetoresistive elements 31b are arranged such that the angle formed between them is larger at a position closer to a central axis Cy, which corresponds to the midpoint in the Y direction, the longitudinal direction of a magnetic field generator containing a magnet 1 and yokes 2a and 2b. The anisotropic magnetoresistive elements 31a and the anisotropic magnetoresistive elements 31b are each of the same size. As shown in Figure 10A, the anisotropic magnetoresistive elements 31a and 31b are arranged such that the angle formed between them is larger at a position closer to a central axis Cy, which corresponds to the midpoint in the Y direction, which is the longitudinal direction of a magnetic field generator containing a magnet 1 and yokes 2a and 2b are arranged such that the angle formed between them is larger at a position closer to a central axis Cy, which corresponds to the midpoint in the Y direction. Fig. As schematically represented in Figure 10B, each anisotropic magnetoresistive element 31a receives a magnetic field that varies less at different positions in the Y-direction. This allows for a more uniform sensitivity distribution, as shown in Figure 10B. Fig. 10C is shown, and a more even signal distribution. Alternative design 2

[0050] A magnetic sensor device according to another embodiment 2 is described with reference to Fig. 11 described.

[0051] In Fig. 11 are components that are in Fig. The three components shown are equivalent, provided with the same reference numbers, and the explanation of such components is omitted.

[0052] In the present embodiment, as in Fig. As shown in Figure 11, anisotropic magnetoresistive elements 31a and 31b, which are closer to a central axis Cy corresponding to the midpoint in the Y direction, which is the longitudinal direction of a magnetic field generator containing a magnet 1 and yokes 2a and 2b, have a smaller width W than anisotropic magnetoresistive elements 31a and 31b, which are farther from the central axis Cy.

[0053] In Fig. 11. The magnitude of a bias field By in the Y-direction at the central axis Cy is small. The bias field By in the Y-direction is larger at a position further away from the central axis Cy. This results in lower sensitivities for the anisotropic magnetoresistive elements 31a and 31b. Therefore, the anisotropic magnetoresistive elements 31a and 31b have a greater width W at a position further away from the central axis Cy, so that the output values ​​of the anisotropic magnetoresistive elements 31 and 31b remain unchanged. This leads to the magnetic sensor device 100 appearing to have a more uniform sensitivity distribution, which enables a more uniform signal distribution. modification

[0054] The anisotropic magnetoresistive elements 31a and 31b can have a thickness, i.e., a dimension in the Z-direction, which varies depending on the position, instead of or in addition to the width W, which also varies depending on the position, as in Fig. Figure 11 illustrates this. More precisely, the anisotropic magnetoresistive elements 31a and 31b located closer to the central axis Cy can have a greater thickness, i.e., a thicker structure, than the anisotropic magnetoresistive elements 31a and 31b located further away from the central axis Cy. The anisotropic magnetoresistive elements exhibit higher sensitivity when they have a thinner resistive film. Therefore, adjusting the thickness of the anisotropic magnetoresistive elements can produce the same advantageous effects as in the other embodiment 2.

[0055] The structures described in the embodiments of the invention and the other embodiments 1 and 2 can be part of the areas in a magnetic sensor device.

[0056] Being symmetrical here does not mean being exactly symmetrical. The anisotropic magnetoresistive elements 31a and 31b contained in the magnetic sensor device 100 according to the embodiments may exhibit a symmetrical deviation with respect to the central axis Cy that is permissible for its function as a magnetic sensor, a symmetrical deviation resulting from manufacturing variations, or a partially symmetrical deviation for other functions. The symmetry deviations may include deviations in size, position, angle, and orientation.

[0057] In the embodiments of the invention and the other embodiments 1 and 2, the anisotropic magnetoresistive elements 31a and 31b are film resistors. In some embodiments, the anisotropic magnetoresistive elements 31a and 31b can be resistors, each having a meandering or folded pattern, as shown in Fig. Figure 10 in JP 6 316 429 shows that the width W of each of the anisotropic magnetoresistive elements 31a and 31b can be proportional to the number of folds of the resistor. More precisely, the anisotropic magnetoresistive elements 31a and 31b with a smaller width each have fewer folds and therefore lower resistance, while the anisotropic magnetoresistive elements 31a and 31b with a larger width W each have more folds and therefore higher resistance.

[0058] Each embodiment of the present disclosure can be suitably combined, modified, or eliminated within the scope of this disclosure. Although the anisotropic magnetoresistive elements are examples of resistors intended to be magnetoresistive elements, giant magnetoresistive (GMR) elements or tunnel magnetoresistive (TMR) elements, for example, can be used to achieve the same advantageous effects.

[0059] Although the above explanations use eight pairs, or eight sets, of magnetoresistive elements, any number of pairs can be used. Pairs or sets of magnetoresistive elements that are to be axially symmetric can be any number of pairs or sets, which in total contain at least two pairs or sets, including one set in the positive Y-direction from the central axis Cy and one set in the negative Y-direction.

[0060] Although the anisotropic magnetoresistive elements 31a and the anisotropic magnetoresistive elements 31b in the examples are axially symmetric with respect to the central axis Cx in the longitudinal direction of the magnetic field generating unit, in some embodiments they may be arranged in any other way than axially symmetric. Reference symbol list 1 magnet 2a, 2b Yoke 3 Chip with anisotropic magnetoresistive element 4 cases 5 Metallic shielding plate 6 circuit board 7 Signal processing board 8 cables 31a, 31b Anisotropic magnetoresistive element

Claims

[1] Magnetic sensor device comprising: a magnetic field generator for generating a magnetic field that intersects a detection object (50); and a plurality of sets of magnetoresistive elements arranged in a line in a longitudinal direction, wherein the longitudinal direction is perpendicular to a direction of movement of the detection object (50), wherein Each of the plurality of sets of magnetoresistive elements contains a first resistor (31a) and a second resistor (31b) arranged with a distance between them in the direction of motion, wherein a center point of the first resistor and the second resistor is adapted to a center of the magnetic field generator in the direction of motion, the magnetic field generator applies a magnetic field to a plurality of the first resistors (31a) and a plurality of the second resistors (31b), which contains a component in the direction of movement of the detection object and a component in the longitudinal direction, the first resistor (31a) and the second resistor (31b) in each of the plurality of sets of magnetoresistive elements are arranged such that the distance increases from a distance between first ends of the first resistor (31a) and the second resistor (31b) in the longitudinal direction to a distance between second ends of the first resistor (31a) and the second resistor (31b) in the longitudinal direction, and at least two sets of the first resistor (31a) and the second resistor (31b) are arranged such that they are axially symmetric with respect to an axis of the magnetic field generator which runs perpendicular to the longitudinal direction, a first group (A) of the plurality of sets of magnetoresistive elements is arranged on a first side, in the longitudinal direction, of a central axis (Cy) of the magnetic field generator in the longitudinal direction, wherein the central axis (Cy) intersects a center, in the longitudinal direction, of the magnetic field generator and is perpendicular to the longitudinal direction, a second group (B) of the plurality of sets of magnetoresistive elements is arranged on a second side, in the longitudinal direction, of the central axis (Cy), in each set of magnetoresistive elements in the first group (A) the first ends of the first resistor (31a) and the second resistor (31b) are closer to the central axis (Cx) than the second ends of the first resistor (31a) and the second resistor (31b), and In all but one set of magnetoresistive elements in the second group (B), the first ends of the first resistor (31a) and the second resistor (31b) are closer to the central axis (Cx) than the second ends of the first resistor (31a) and the second resistor (31b). [2] Magnetic sensor device according to claim 1, wherein the first resistor (31a) and the second resistor (31b) in each of the sets of magnetoresistive elements are axially symmetric about an axis (Cx) parallel to the longitudinal direction. [3] Magnetic sensor device according to one of claims 1 or 2, wherein the plurality of first resistors (31a) and the plurality of second resistors (31b), which are arranged to extend in the longitudinal direction of the magnetic field generator, are arranged such that a first resistor (31a) included in the plurality of first resistors (31a) and a second resistor (31b) included in the plurality of second resistors (31b) have a greater thickness than another first resistor (31a) included in the plurality of first resistors (31a) and another second resistor (31b) included in the plurality of second resistors (31b), and the first resistor (31a) and the second resistor (31b) are located closer to a central axis (Cy) of the magnetic field generator in the longitudinal direction than the other first resistor (31a) and the other second resistor (31b). [4] Magnetic sensor device according to one of claims 1 to 3, wherein the magnetic field generator applies a magnetic field to the plurality of first resistors (31a) and the plurality of second resistors (31b), wherein the magnetic field is generated in opposite directions in the longitudinal direction with respect to a central axis (Cy) of the magnetic field generator. [5] Magnetic sensor device comprising: a magnetic field generator for generating a magnetic field that intersects a detection object (50); and a plurality of sets of magnetoresistive elements arranged in a line in a longitudinal direction, wherein the longitudinal direction is perpendicular to a direction of movement of the detection object (50), wherein Each of the plurality of sets of magnetoresistive elements contains a first resistor (31a) and a second resistor (31b) arranged with a distance between them in the direction of motion, wherein a center point of the first resistor and the second resistor is adapted to a center of the magnetic field generator in the direction of motion, the magnetic field generator applies a magnetic field to a plurality of the first resistors (31a) and a plurality of the second resistors (31b), which contains a component in the direction of movement of the detection object and a component in the longitudinal direction, the first resistor (31a) and the second resistor (31b) in each of the plurality of sets of magnetoresistive elements are arranged such that the distance increases from a distance between first ends of the first resistor (31a) and the second resistor (31b) in the longitudinal direction to a distance between second ends of the first resistor (31a) and the second resistor (31b) in the longitudinal direction, and at least two sets of the first resistor (31a) and the second resistor (31b) are arranged such that they are axially symmetric with respect to an axis of the magnetic field generator which runs perpendicular to the longitudinal direction, wherein the first resistor (31a) and the second resistor (31b) in each of the plurality of sets of magnetoresistive elements are arranged such that a long side of each resistor is aligned at an orientation angle with respect to a central axis (Cy) of the magnetic field generator, and the orientation angle of each of the first resistor (31a) and the second resistor (31b) in a first set of the plurality of sets of magnetoresistive elements is less than or equal to the orientation angle of each of the first resistor (31a) and the second resistor (31b) in a second set of the plurality of sets of magnetoresistive elements, wherein the first set of the plurality of sets of magnetoresistive elements is closer to the central axis (Cy) than the wider set of the plurality of sets of magnetoresistive elements, and wherein an orientation angle of the first and second resistors (31a, 31b) in a set of the plurality of sets of magnetoresistive elements, which is closer to the central axis (Cy) of the magnetic field generator in the longitudinal direction, differs from an orientation angle of the first and second resistors (31a, 31b) in a set of the plurality of sets of magnetoresistive elements, which is furthest from the central axis (Cy) of the magnetic field generator in the longitudinal direction, wherein the central axis (Cy) intersects a center point of the magnetic field generator extending perpendicular to the longitudinal direction.

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