Magnetic sensor device

Abstract

The magnetic sensor device includes a magnet that generates a magnetic field and a magnetoresistive effect element arranged in a longitudinal direction perpendicular to the transmission direction of the object to be detected. The first resistor (31a) and the second resistor (31b) of the magnetoresistive effect element are arranged so that the center of the interval between the first resistor (31a) and the second resistor (31b) in the transmission direction is located at the central axis (Cx) of the magnet in the transmission direction. The magnet applies a magnetic field having a transmission direction component and a longitudinal direction component of the object to be detected to the first resistor (31a) and the second resistor (31b). The first resistor (31a) and the second resistor (31b) are arranged so that the interval between them increases from one end of the first resistor (31a) and the second resistor (31b) toward the other end in the longitudinal direction, and at least two groups of the first resistor (31a) and the second resistor (31b) are arranged in a line-symmetrical manner with respect to a virtual line (Cy') perpendicular to the longitudinal direction of the magnet.

Description

Technical Field

[0001] The present application relates to magnetic sensor devices. Background Art

[0002] Magnetic sensor devices are known that use multiple magnetoresistive elements whose resistance changes with magnetic flux density. For example, Patent Document 1 discloses a magnetic sensor device that uses multiple magnetoresistive elements to detect magnetic patterns contained in paper media such as banknotes across multiple channels.

[0003] In order to improve detection sensitivity, the magnetic sensor device described in Patent Document 1 bridges two magnetoresistive effect elements adjacent to each other in the transmission direction (hereinafter referred to as the X-axis direction).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 6316429

[0007] Patent Document 2: Japanese Patent No. 6300908 Summary of the Invention

[0008] Technical problem to be solved by the invention

[0009] The applied magnetic flux-resistance characteristic of a magnetoresistive element exhibits hysteresis. Therefore, if the two magnetoresistive elements forming the bridge have different hysteresis effects after reading a paper medium, the difference in hysteresis effects affects the voltage divider ratio, making it difficult to obtain a stable output signal.

[0010] In order to deal with this problem, in Patent Document 1 Figure 9 In this technique, a pair of magnetoresistive elements are arranged so that the distance between them increases from one end toward the other in the reading width direction. This structure allows the X-axis magnetic field applied by a permanent magnet to stably apply a bias magnetic field in the longitudinal direction (i.e., the non-magnetic sensitive direction) of the magnetoresistive elements, thereby suppressing resistance fluctuations caused by hysteresis characteristics and achieving a stable output.

[0011] However, with this configuration, in the region where the Y-axis bias magnetic field By is negative, the longitudinal component of the magnetoresistive element due to the magnetic field By and the longitudinal component of the X-axis bias magnetic field Bx cancel each other out. Consequently, the magnetic field applied longitudinally to the magnetoresistive element weakens, impairing the stability of the output signal.

[0012] To address the aforementioned issues, Patent Document 2 discloses a structure in which micromagnets are placed at the ends of the longitudinal sides of a magnet to forcibly apply a bias magnetic field in the same direction in the non-magnetic direction of each anisotropic magnetoresistive element arranged along a line. However, the structure of Patent Document 2 complicates the structure of the magnet providing the bias magnetic field.

[0013] The present disclosure has been made to solve the above-mentioned problems, and an object thereof is to provide a magnetic sensor device that has a simple structure and can obtain a stable output.

[0014] Technical means for solving technical problems

[0015] In order to achieve the above-mentioned purpose, the magnetic sensor device involved in the present disclosure includes: a magnetic field generating member that generates a magnetic field that intersects with the object to be detected; and a magnetoresistive effect element that is arranged on a straight line in the longitudinal direction with a direction perpendicular to the transmission direction of the object to be detected as the longitudinal direction. The magnetoresistive effect element has a structure in which a first resistor and a second resistor are arranged so that the center of the gap between the first resistor and the second resistor in the transmission direction is located at the center position of the magnetic field generating member in the transmission direction. The magnetic field generating member applies a component having a transmission direction of the object to be detected and a component in the longitudinal direction to the first resistor and the second resistor. The first resistor and the second resistor are arranged so that the gap between the first resistor and the second resistor increases as they move from one end of the first resistor and the second resistor toward the other end in the longitudinal direction, and at least two groups of the first resistor and the second resistor are arranged in a line-symmetrical manner with respect to an axis of the magnetic field generating member that is perpendicular to the longitudinal direction.

[0016] Effects of the Invention

[0017] According to the present disclosure, at least two sets of first and second resistors are arranged in line symmetry about an axis perpendicular to the longitudinal direction of the magnetic field generating member. Therefore, when considering the magnetic field applied in the longitudinal direction of each resistor, the transmission direction component and the longitudinal direction component of the magnetic field applied by the magnetic field generating member are summed regardless of the orientation of the longitudinal direction component. This allows for a simple structure to stably apply a magnetic field in the longitudinal direction of the resistors, suppressing hysteresis and achieving a stable output. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a cross-sectional view parallel to the conveying direction of the object to be detected of the magnetic sensor device according to the first embodiment of the present disclosure, Figure 2 Line II cross-sectional view.

[0019] Figure 2 is a cross-sectional view of the magnetic sensor device according to Embodiment 1 as viewed from the insertion and removal direction of the object to be detected. Figure 1 Cross-sectional view along line II-II.

[0020] Figure 3A 1 is a structural diagram of the AMR chip according to the first embodiment, and is a diagram showing the arrangement of a plurality of magnetoresistive effect element pairs.

[0021] Figure 3B This is a circuit diagram of the AMR chip according to the first embodiment.

[0022] Figure 4 This is a distribution diagram of the magnetic field generated by the magnet according to the first embodiment.

[0023] Figure 5 Yes Figure 1 Graph showing the distribution of the Y-axis bias magnetic field By applied to the magnetoresistive element.

[0024] Figure 6A Is the description applied to Figure 3A Graph showing the longitudinal component of the magnetic field of the magnetoresistive element shown.

[0025] Figure 6B Is the description applied to Figure 3A Graph showing the longitudinal component of the magnetic field of the magnetoresistive element shown.

[0026] Figure 6C Is the description applied to Figure 3A Graph showing the longitudinal component of the magnetic field of the magnetoresistive element shown.

[0027] Figure 7 This is a top view of the AMR chip of the magnetic sensor device according to the second embodiment of the present disclosure.

[0028] Figure 8 Yes Figure 7 FIG. 4 is a graph showing the relationship between the position of each magnetoresistive element in the AMR chip in the Y-axis direction and the strength of the magnetic field applied in the longitudinal direction of the element.

[0029] Figure 9 Yes Figure 7 FIG. 4 is a graph showing the relationship between the position of each magnetoresistive element in the AMR chip in the Y-axis direction and its sensitivity.

[0030] Figure 10A This is a top view of the AMR chip of the magnetic sensor device in the third embodiment of the present disclosure.

[0031] Figure 10B Yes Figure 10A A diagram showing the relationship between the orientations of the magnetoresistive elements shown.

[0032] Figure 10C Yes Figure 10AFIG. 4 is a graph showing the relationship between the position of each magnetoresistive element in the AMR chip in the Y-axis direction and its sensitivity.

[0033] Figure 11 This is a top view of the AMR chip of the magnetic sensor device according to the fourth embodiment of the present disclosure. DETAILED DESCRIPTION

[0034] Hereinafter, a magnetic sensor device according to an embodiment of the present disclosure will be described.

[0035] In addition, in the following description, the transmission direction of the object to be detected, that is, the short side direction of the magnetic sensor device, is defined as the X-axis direction, the long side direction of the magnetic sensor device orthogonal to the transmission direction of the object to be detected, that is, the reading width direction, is defined as the Y-axis direction, and the direction perpendicular to the XY plane serving as the transmission surface is defined as the Z direction, and appropriate references are made thereto.

[0036] (Implementation 1)

[0037] Figure 1 is a ZX cross-sectional view of the magnetic sensor device 100 according to the first embodiment. Figure 2 FIG. 3 is a YZ cross-sectional view of the magnetic sensor device 100 , and FIG. 4 is a top view of the anisotropic magnetoresistive effect element chip of the magnetic sensor device 100 . Figure 1 Equivalent to Figure 2 II line profile, Figure 2 Equivalent to Figure 1 II-II line section.

[0038] As shown in the figure, the magnetic sensor device 100 includes a magnet 1 that generates a bias magnetic field, magnetic yokes 2a and 2b that form a magnetic circuit, an anisotropic magnetoresistive effect element chip 3 that outputs changes in the magnetic field as changes in resistance value, a shell 4 that accommodates the magnet 1 and the magnetic yokes 2a and 2b, a metal shielding plate 5 for shielding magnetism, a circuit substrate 6 for detecting changes in the resistance value of the magnetoresistive effect element, and a signal processing circuit substrate 7 for processing the detection signal output by the circuit substrate 6.

[0039] Magnet 1 comprises a rectangular permanent magnet having north and south poles in the Z-axis direction, and is elongated in the Y-axis direction and short in the X-axis direction. Magnet 1 forms a magnetic field generator that applies a bias magnetic field to anisotropic magnetoresistive element chip 3.

[0040] Yoke 2a and yoke 2b are each plate-shaped and made of a soft magnetic material such as iron. Yoke 2a is attached to the upper surface of magnet 1, while yoke 2b is attached to the lower surface of magnet 1. Yokes 2a and 2b form part of the magnetic field generating unit, transmitting the magnetic flux generated by magnet 1. Yokes 2a and 2b are not essential components and can be positioned as needed.

[0041] An anisotropic magnetoresistive effect element chip 3 (hereinafter referred to as AMR chip 3) is arranged on the upper surface of the yoke 2a and outputs the change of the applied magnetic flux as the change of the resistance value. The AMR chip 3 will be described in detail later.

[0042] The housing 4 is made of resin or ceramics, and is formed in a box shape with an open top surface, and houses the magnet 1 and the yokes 2 a and 2 b.

[0043] The metal shield plate 5 covers and protects the circuit board 6 and the AMR chip 3 on the transmission path side of the object 50. The metal shield plate 5 itself is not magnetized and allows magnetic lines of force to pass through.

[0044] The circuit board 6 surrounds the AMR chip 3 and is placed on the upper surface of the yoke 2a. The circuit board 6 applies a power supply voltage VDD and a ground voltage GND to the AMR chip 3 and outputs a detection signal indicating a change in resistance of the magnetoresistive element.

[0045] The signal processing circuit board 7 is disposed at the lower portion of the housing 4 and is connected to the circuit board 6 via a cable 8 . The signal processing circuit board 7 processes the detection signal and detects the object to be detected 50 .

[0046] The object to be detected 50 is a thin sheet-like object to be detected, such as a banknote printed with a magnetic material such as magnetic ink, etc. The conveying direction of the object to be detected 50 is the +X axis direction.

[0047] Next, the details of the AMR chip 3 will be described with reference to FIG. 3 .

[0048] The AMR chip 3 includes eight pairs of anisotropic magnetoresistive effect elements 31a and 31b, which are arranged on a virtual line in line symmetry with respect to a central axis Cx passing through the center of the chip in the X-axis direction and extending in the Y-axis direction as the longitudinal direction.

[0049] The anisotropic magnetoresistive effect elements 31 a and 31 b have long sides and short sides, respectively, in a plan view. The short side direction is a magnetically sensitive direction, and the long side direction is a magnetically non-sensitive direction.

[0050] Anisotropic magnetoresistive effect elements 31a and 31b are examples of a first resistor and a second resistor. Anisotropic magnetoresistive effect elements 31a and 31b are arranged so that the longitudinal center axis Cx is the center position of the magnetic field generating member, including magnet 1 and yokes 2a and 2b, in the X-axis direction. Anisotropic magnetoresistive effect elements 31a and 31b are arranged in a line-symmetrical manner with respect to the longitudinal center axis Cx.

[0051] Anisotropic magnetoresistive elements 31a and 31b are arranged so that the distance between them increases or decreases along the Y-axis. Furthermore, at least two pairs of anisotropic magnetoresistive elements 31a and 31b are arranged line-symmetrically with respect to the central axis Cy of the magnetic field generating member, which includes magnet 1 and yokes 2a and 2b, in the Y-axis direction. Central axis Cy passes through the center of AMR chip 3 in the Y-axis direction and extends in the X-axis direction, which is the short side direction.

[0052] Specifically, in Figure 3A In the example shown in FIG. 1 , in the region closer to the +Y axis than the imaginary line Cy' perpendicular to the longitudinal direction of the magnet 1, there are five pairs, or five groups, of anisotropic magnetoresistive effect elements 31a and 31b arranged with their spacing increasing as Y increases. In the region closer to the -Y axis than the imaginary line Cy', there are three pairs, or three groups, of anisotropic magnetoresistive effect elements 31a and 31b arranged with their spacing decreasing as Y increases. Therefore, a total of six groups, three each, of anisotropic magnetoresistive effect elements 31a and 31b are arranged line-symmetrically with respect to the central axis Cy in the Y direction. Furthermore, the spacing between anisotropic magnetoresistive effect elements 31a and 31b in Group A, which consists of five groups, increases as Y increases. The spacing between anisotropic magnetoresistive effect elements 31a and 31b in Group B, which consists of three groups, decreases as Y increases. Furthermore, the five sets of anisotropic magnetoresistive effect elements 31 a and 31 b belonging to group A and the three sets of anisotropic magnetoresistive effect elements 31 a and 31 b belonging to group B are arranged line-symmetrically with respect to the central axis Cx in the Y-axis direction.

[0053] like Figure 3B As shown, power supply voltage VDD is applied to one end of each anisotropic magnetoresistive effect element 31a via circuit board 6. Ground voltage GND is applied to one end of each anisotropic magnetoresistive effect element 31b. The other ends of anisotropic magnetoresistive effect elements 31a and 31b are short-circuited, and the output of each pair is output to circuit board 6 via an output signal line.

[0054] In such a configuration, the power supply voltage VDD is divided according to the ratio of the resistance values of the anisotropic magnetoresistive effect elements 31 a and 31 b , and is output as a detection signal to the output signal line.

[0055] Passing a magnetic object 50 through the transmission path changes the magnetic field applied to each of the anisotropic magnetoresistive elements 31a and 31b, causing their resistance to change, changing the voltage divider ratio, and thus the voltage of the detection signal. Circuit board 6 transmits the detection signal to signal processing circuit board 7, which processes the detection signal to detect object 50.

[0056] Next, a description will be given of a configuration for applying a bias magnetic field to the anisotropic magnetoresistive effect elements 31 a and 31 b in the magnetic sensor device 100 .

[0057] Figure 4 : is a diagram showing the distribution of magnetic lines of force output by a magnetic field generating unit including the magnet 1 and the yokes 2a and 2b. Figure 4 The structural elements required to describe the distribution of magnetic field lines are recorded, and the others are omitted. Figure 4 As shown, when viewed in the XZ plane, magnetic flux 20 generated from the north pole of magnet 1 passes through yoke 2a and is released from the XY and YZ surfaces of yoke 2a to the outside of magnet 1 and yoke 2a. Magnetic flux 20 released to the outside of magnet 1 and yoke 2a then enters yoke 2b from the XY and YZ surfaces of yoke 2b, which is located on the south pole side of magnet 1. Magnetic flux 20 entering yoke 2b is then concentrated on the south pole of magnet 1 by yoke 2b.

[0058] Here, the X-axis center axis of the AMR chip 3, i.e., the longitudinal center axis Cx, is positioned at the X-axis center of the magnet 1 and the yoke 2a. Similarly, the Y-axis center axis of the AMR chip 3, i.e., the longitudinal center axis Cy, is positioned at the Y-axis center of the magnet 1 and the yoke 2a.

[0059] Therefore, the X-axis component +Bx of the magnetic field represented by the magnetic field lines 20 acts as an X-axis bias magnetic field for the anisotropic magnetoresistive effect element 31a. Conversely, on the anisotropic magnetoresistive effect element 31b, the -X-axis component -Bx acts as an X-axis bias magnetic field for the anisotropic magnetoresistive effect element 31b. Figure 3A and Figure 4 This relationship is shown in . This bias magnetic field stably applies a magnetic field in the longitudinal direction of the anisotropic magnetoresistive effect elements 31a and 31b. This suppresses the hysteresis characteristics of the anisotropic magnetoresistive effect elements 31a and 31b, and enables stable output.

[0060] On the other hand, in the Y-axis direction, the AMR chip 3 and the magnet 1 are longer than in the X-axis direction, so a force of approximately Figure 5 The intensity distribution of the magnetic field is shown in FIG. Figure 3A In the top view of the central axis Cy, in theory, a magnetic field in the +Y direction is applied to the area on the +Y side, i.e., the right side of the central axis Cy. In addition, a magnetic field in the -Y direction is applied to the area on the -Y side, i.e., the left side of the central axis Cy. However, in the central part, i.e., Figure 5 In the range of (a), the Y-axis direction bias magnetic field By can be basically considered to be "0".

[0061] Here, consider the end portion closer to the +Y axis side than the central axis Cy. Figure 5The range of (b) in the figure is the configuration at the right end. Figure 6A As shown, the applied magnetic field in the longitudinal direction of anisotropic magnetoresistive effect element 31a is the sum of the longitudinal component / / Bx of the anisotropic magnetoresistive effect element 31a of the X-axis bias magnetic field Bx and the longitudinal component / / By of the Y-axis bias magnetic field By. Therefore, a stable bias magnetic field in the longitudinal direction of anisotropic magnetoresistive effect element 31a is provided by both the X-axis bias magnetic field Bx and the Y-axis bias magnetic field By.

[0062] Next, consider the end portion closer to the -Y axis side than the central axis Cy. Figure 5 The range of (c) in the figure is the configuration at the left end. Figure 6B As shown in FIG, the Y-axis bias magnetic field By is oriented in the -Y-axis direction. On the other hand, the X-axis bias magnetic field Bx is oriented in the -Y-axis direction. Figure 6A The same. Consider the case of anisotropic magnetoresistive effect elements 31a and 31b located in region (c), arranged so that the spacing between them widens as Y increases. In this case, in the applied magnetic field in the longitudinal direction of anisotropic magnetoresistive effect element 31a, the longitudinal component / / Bx of the anisotropic magnetoresistive effect element 31a of the X-axis bias magnetic field Bx and the longitudinal component / / By of the anisotropic magnetoresistive effect element 31a of the Y-axis bias magnetic field By are opposite and cancel each other out. Therefore, the difference between them becomes the longitudinal bias magnetic field. As a result, the longitudinal bias magnetic field of anisotropic magnetoresistive effect element 31a becomes smaller, and anisotropic magnetoresistive effect element 31a is easily affected by hysteresis.

[0063] On the other hand, Figure 3A In the structure, in the region closer to the -Y axis than the imaginary line Cy' perpendicular to the longitudinal direction of the magnet 1, there are three sets of anisotropic magnetoresistive effect elements 31a and 31b arranged with the intervals narrowing as Y increases.

[0064] In this case, if Figure 6C As shown in FIG. 1 , if the bias magnetic field in the X-axis direction is Bx and the bias magnetic field in the -Y-axis direction is By, the component of the applied magnetic field in the longitudinal direction of the anisotropic magnetoresistive effect element 31a becomes the sum of the longitudinal component / / Bx of the anisotropic magnetoresistive effect element 31a due to the X-axis bias magnetic field Bx and the longitudinal component / / Bx of the anisotropic magnetoresistive effect element 31b due to the Y-axis bias magnetic field By. Figure 5 In the range of (c), the anisotropic magnetoresistive effect elements 31a and 31b are configured in a manner where the intervals become narrower as Y increases, and a long-side bias magnetic field is stably provided to the anisotropic magnetoresistive effect element 31a through the X-axis bias magnetic field Bx and the Y-axis bias magnetic field By.

[0065] As described above, in this embodiment, within the range of the magnet end, regardless of whether the direction of the bias magnetic field By in the Y-axis direction is in the positive region or the negative region, for at least a portion of the pairs of anisotropic magnetoresistive effect elements 31a and 31b, the bias magnetic field Bx in the X-axis direction and the bias magnetic field By in the Y-axis direction are added together as the bias magnetic field in the longitudinal direction of the anisotropic magnetoresistive effect elements 31a and 31b. This is in contrast to the case of Patent Document 1, in which the spacing between all anisotropic magnetoresistive effect elements 31a and 31b is increased in the same direction. Figure 9 Compared with the configuration described in , stable output can be obtained in a wider area, especially near the end.

[0066] Furthermore, the magnetic sensor device 100 of the present embodiment has improved uniformity in sensitivity distribution, and can obtain a more uniform signal distribution.

[0067] (Implementation Method 2)

[0068] In the first embodiment, at least two or more sets of six groups, that is, six pairs of anisotropic magnetoresistive effect elements 31a and anisotropic magnetoresistive effect elements 31b are arranged to be line-symmetrical with respect to the central axis Cy. However, this configuration is not limited thereto, and any configuration may be made as long as at least two or more sets are line-symmetrical with respect to the central axis Cy. For example, Figure 7 As shown, all four sets of anisotropic magnetoresistive elements 31a and 31b located in the positive Y-axis region relative to the central axis Cy, and all four sets of anisotropic magnetoresistive elements 31a and 31b located in the negative Y-axis region relative to the central axis Cy, totaling eight sets, can be arranged in line symmetry with respect to the central axis Cy. This line symmetry eliminates the need to manufacture multiple AMR chips 3. Instead, a single pattern master for forming the anisotropic magnetoresistive elements 31a and 31b on the AMR chip 3 can be manufactured, thereby reducing costs.

[0069] In this case, if Figure 8 As shown in FIG. 1 , the bias magnetic field B in the longitudinal direction of the anisotropic magnetoresistive effect elements 31a and 31b is substantially uniform regardless of the position in the Y-axis direction. Figure 9 As shown, the sensitivity is also independent of the position along the Y-axis and is basically uniform.

[0070] (Implementation 3)

[0071] The magnetic sensor device 100 according to the third embodiment will be described with reference to FIG10. Figure 3A The same or equivalent components are denoted by the same reference numerals, and their description is omitted.

[0072] Figure 10AThis is a top view of the AMR chip 3 of the magnetic sensor 100 in the third embodiment. In this structure, the anisotropic magnetoresistive effect element 31a and the anisotropic magnetoresistive effect element 31b are arranged so that the angle formed by them becomes larger as they are closer to the central axis Cy. The central axis Cy corresponds to the midpoint of the long side direction, i.e., the Y-axis direction, of the magnetic field generating member including the magnet 1 and the yokes 2a and 2b. The anisotropic magnetoresistive effect elements 31a and 31b are of the same size. In this case, Figure 10B As schematically shown in FIG, the difference caused by the position of the magnetic field applied to the magnetoresistive element 31a in the Y-axis direction becomes smaller. Figure 10C As shown, the uniformity of the sensitivity distribution is improved, and a more uniform signal distribution can be obtained.

[0073] (Implementation 4)

[0074] Reference Figure 11 A magnetic sensor device 100 according to the fourth embodiment will be described.

[0075] Figure 11 3 , the same reference numerals are used for the structural elements that are the same as or correspond to those in FIG3 , and their descriptions are omitted.

[0076] like Figure 11 As shown, in this embodiment, the width W of the anisotropic magnetoresistive effect elements 31a and 31b on the side close to the central axis Cy is smaller than the width W of the anisotropic magnetoresistive effect elements 31a and 31b on the side away from the central axis Cy, and the central axis Cy is equivalent to the midpoint of the long side direction, i.e., the Y-axis direction, of the magnetic field generating component including the magnet 1 and the yokes 2a and 2b.

[0077] exist Figure 11 In the example, the magnitude of the Y-axis bias magnetic field By is minimal at the center axis Cy. However, as the distance from the center axis Cy increases, the Y-axis bias magnetic field By increases, affecting the sensitivity of the anisotropic magnetoresistive effect elements 31a and 31b, causing the sensitivity to decrease. Therefore, by increasing the width W of the anisotropic magnetoresistive effect elements 31a and 31b as the distance from the center axis Cy increases, the output values from the anisotropic magnetoresistive effect elements 31a and 31b remain constant. This apparently improves the uniformity of the sensitivity distribution of the magnetic sensor device 100, enabling a uniform signal distribution.

[0078] (Variation)

[0079] As Figure 11Instead of varying the width W of the anisotropic magnetoresistive effect elements 31a and 31b depending on position, or in addition to varying the width W depending on position, the thickness of the anisotropic magnetoresistive effect elements 31a and 31b, i.e., their size in the Z-axis direction, can be varied depending on position. More specifically, the thickness of the anisotropic magnetoresistive effect elements 31a and 31b on the side closer to the central axis Cy is greater than that on the side farther from the central axis Cy. Anisotropic magnetoresistive effect elements have the characteristic of increasing sensitivity as the resistive film is thinner. Therefore, by adjusting the thickness, the same effects as in Embodiment 4 can be achieved.

[0080] The portion having the structures described in Embodiments 1 to 4 may be provided as only a partial region of the magnetic sensor device.

[0081] In this specification, "symmetry" does not necessarily mean symmetry in the strict sense. In the magnetic sensor device 100 of the embodiment, the anisotropic magnetoresistive effect elements 31a and 31b may have symmetry deviations relative to the central axis Cy sufficient to function as magnetic sensors, symmetry deviations due to manufacturing errors, and local symmetry deviations for other functional purposes. These deviations may include any of dimensional deviations, positional deviations, angular or directional deviations, and the like.

[0082] In the above description, the anisotropic magnetoresistive effect elements 31a and 31b are depicted as a single resistor. However, as shown in FIG10 of Patent No. 6316429 (Patent Document 1), the resistor may also have a meandering structure, i.e., a folded pattern. Furthermore, the width W of the anisotropic magnetoresistive effect elements 31a and 31b is proportional to the number of folds in the resistor. Specifically, when the width W of the anisotropic magnetoresistive effect elements 31a and 31b is smaller, the number of folds in the resistor is smaller, resulting in a lower resistance value of the anisotropic magnetoresistive effect elements 31a and 31b. When the width W of the anisotropic magnetoresistive effect elements 31a and 31b is larger, the number of folds in the resistor is greater, resulting in a higher resistance value of the magnetoresistive effect elements 31a and 31b.

[0083] Furthermore, the present disclosure allows for the free combination of embodiments within the scope of this disclosure, as well as for appropriate modifications and omissions of the embodiments. For example, while an example of an anisotropic magnetoresistive element is shown as a resistor constituting a magnetoresistive element, the same effect can be achieved by using a GMR (Giant Magneto Resistive Effect) element, a TMR (Tunnel Magneto Resistive Effect), or the like.

[0084] While an example of eight pairs or groups of magnetoresistive elements is shown, the number of pairs is arbitrary. Furthermore, the number of pairs or groups arranged in a line-symmetrical manner is also arbitrary, as long as there is one group on the +Y side of the central axis Cy and one group on the -Y side, for a total of two or more groups.

[0085] Furthermore, although the example in which the anisotropic magnetoresistive effect elements 31 a and the anisotropic magnetoresistive effect elements 31 b are arranged line-symmetrically with respect to the longitudinal central axis Cx of the magnetic field generating unit is shown, they do not need to be line-symmetrical.

[0086] The device structure, circuit structure, etc. are exemplary and can be changed appropriately.

[0087] Various embodiments and variations of the present disclosure may be implemented without departing from the broad spirit and scope of the present disclosure. Furthermore, the aforementioned embodiments are intended to illustrate the present disclosure and do not limit its scope. That is, the scope of the present disclosure is indicated by the scope of the claims, not by the embodiments. Furthermore, variations implemented within the scope of the claims and their equivalents are also considered to be within the scope of the present disclosure.

[0088] This application is based on Japanese Patent Application No. 2019-144767 filed on August 6, 2019. The specification, claims, and all drawings of Japanese Patent Application No. 2019-144767 are incorporated herein by reference.

[0089] Label Description

[0090] 1 magnet

[0091] 2a, 2b yoke

[0092] 3Anisotropic magnetoresistive effect element chip

[0093] 4 Shell

[0094] 5 metal shielding plate

[0095] 6 Circuit board

[0096] 7Signal processing circuit board

[0097] 8 cables

[0098] 31a and 31b are anisotropic magnetoresistive effect elements.

Claims

1. A magnetic sensor device, characterized in that include: a magnetic field generating member for generating a magnetic field intersecting the object to be detected; as well as a magnetoresistive effect element having a longitudinal direction perpendicular to a conveying direction of the object to be detected and arranged on a straight line in the longitudinal direction; The magnetoresistive element has a structure in which a first resistor and a second resistor are arranged such that the center of the interval between the first resistor and the second resistor in the transmission direction is located at the center position of the magnetic field generating member in the transmission direction. The magnetic field generating member applies a magnetic field having a component in the transmission direction of the object to be detected and a component in the longitudinal direction to the first resistor and the second resistor. The first resistor and the second resistor are arranged so that the distance between them increases from one end of the first resistor and the second resistor toward the other end in the longitudinal direction. At least two sets of the first resistor and the second resistor are arranged in line symmetry with respect to an axis perpendicular to the longitudinal direction of the magnetic field generating member. A first group of the plurality of magnetoresistive effect elements is arranged closer to a first side in the longitudinal direction than a central axis of the magnetic field generating member, wherein the central axis intersects the center in the longitudinal direction of the magnetic field generating member and extends perpendicular to the longitudinal direction. A second group of the plurality of magnetoresistive effect elements is arranged closer to a second side in the longitudinal direction than the central axis. In the magnetoresistive effect elements of the first group, one end of the first resistor and the second resistor is closer to the central axis than the other end of the first resistor and the second resistor. In all of the magnetoresistive effect elements except one of the second groups, one ends of the first resistor and the second resistor are closer to the central axis than the other ends of the first resistor and the second resistor.

2. The magnetic sensor device according to claim 1, wherein The set of the first resistor and the second resistor is arranged line-symmetrically with respect to an axis passing through the center of the short side direction perpendicular to the long side direction of the magnetic field generating member and along the long side direction.

3. The magnetic sensor device according to claim 1 or 2, wherein: For the groups of the magnetoresistive effect elements consisting of pairs of the first resistor and the second resistor, all groups are arranged in a line-symmetrical manner with respect to a central axis, which is an axis perpendicular to the long side direction and at the center of the long side direction of the magnetic field generating component.

4. The magnetic sensor device according to claim 1 or 2, wherein: The first resistor and the second resistor extending along the long side direction of the magnetic field generating component are configured so that the angle formed by the first resistor and the second resistor on the side close to the central axis of the long side direction of the magnetic field generating component and the central axis becomes less than the angle formed by the first resistor and the second resistor on the side away from the central axis and the central axis.

5. The magnetic sensor device according to claim 1 or 2, wherein: The first resistor and the second resistor extending along the long side direction of the magnetic field generating component are configured so that the width of the first resistor and the second resistor on the side close to the central axis of the long side direction of the magnetic field generating component is smaller than the width of the first resistor and the second resistor on the side away from the central axis.

6. The magnetic sensor device according to claim 1 or 2, wherein: The first resistor and the second resistor extending along the long side direction of the magnetic field generating component are configured so that the thickness of the first resistor and the second resistor on the side close to the central axis of the long side direction of the magnetic field generating component is thicker than the thickness of the first resistor and the second resistor on the side away from the central axis.

7. The magnetic sensor device according to claim 1 or 2, wherein: The magnetic field generating member applies magnetic fields in opposite directions to the first resistor and the second resistor with reference to the central axis in the longitudinal direction thereof.

8. A magnetic sensor device, characterized in that: include: a magnetic field generating member for generating a magnetic field intersecting the object to be detected; as well as a magnetoresistive effect element having a longitudinal direction perpendicular to a conveying direction of the object to be detected and arranged on a straight line in the longitudinal direction; The magnetoresistive element has a structure in which a first resistor and a second resistor are arranged such that the center of the interval between the first resistor and the second resistor in the transmission direction is located at the center position of the magnetic field generating member in the transmission direction. The magnetic field generating member applies a magnetic field having a component in the transmission direction of the object to be detected and a component in the longitudinal direction to the first resistor and the second resistor. The first resistor and the second resistor are arranged so that the distance between them increases from one end of the first resistor and the second resistor toward the other end in the longitudinal direction. At least two sets of the first resistor and the second resistor are arranged in line symmetry with respect to an axis perpendicular to the longitudinal direction of the magnetic field generating member. The first resistor and the second resistor extending along the long side direction of the magnetic field generating component are configured so that the angle formed by the first resistor and the second resistor on the side close to the central axis of the long side direction of the magnetic field generating component and the central axis becomes less than the angle formed by the first resistor and the second resistor on the side away from the central axis and the central axis.

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