Magnetic sensor, and position detector

Abstract

To provide a magnetic sensor capable of miniaturizing the same.SOLUTION: A magnetic sensor 1 is a magnetic sensor 1 that is configured to detect the position of a detection target based on the changes of the magnetic field strength when the detection target moves relative to a specific direction D1. The magnetic sensor includes: magnetoresistance elements 2 for detecting the relative position arranged in a predetermined direction D1 for detecting the relative position of the detection target; and magnetoresistance elements 3 for detecting the origin arranged in the predetermined direction D1. The magnetoresistance elements 2 for detecting the relative position and the magnetoresistance elements 3 for detecting the origin share at least one of a ground terminal 61 and a power supply terminal 62.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a magnetic sensor and a position detection device.

Background Art

[0002] A position detection device including a magnetic sensor and a magnetic scale has been conventionally known. Patent Document 1 proposes further providing a group of magnetoresistive elements for detecting the origin of the magnetic scale in this type of position detection device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described magnetic sensor, since it further includes a group of magnetoresistive elements for origin detection, the chip size is likely to increase. Therefore, there has been a problem that it is difficult to reduce the size of the magnetic sensor and thus the position detection device.

[0005] The problem to be solved by the present disclosure is to reduce the size of the magnetic sensor and thus the position detection device.

Means for Solving the Problems

[0006] A magnetic sensor according to an aspect of the present disclosure is a magnetic sensor configured to detect the position of a detection target based on a change in magnetic field strength caused by relative movement of the detection target in a predetermined direction, and includes a group of magnetoresistive elements for relative position detection arranged in the predetermined direction to detect the relative position of the detection target, and a group of magnetoresistive elements for origin detection arranged in the predetermined direction to detect the origin of the detection target. The group of magnetoresistive elements for relative position detection and the group of magnetoresistive elements for origin detection share at least one of a ground terminal and a power supply terminal.

[0007] A position detection device according to an aspect of the present disclosure includes the magnetic sensor and a magnetic scale in which N poles and S poles are alternately magnetized in the predetermined direction. The magnetic scale constitutes the detection target.

Effect of the Invention

[0008] The present disclosure has an effect of achieving miniaturization of the magnetic sensor and thus the position detection device.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, the magnetic sensor 1 and the position detection device 9 according to the first embodiment will be described with reference to the accompanying drawings. The drawings referred to in the following embodiments and the like are all schematic diagrams, and the ratios of the sizes and thicknesses of the respective components in the drawings do not necessarily reflect the actual dimensional ratios.

[0011] 1. First Embodiment (Position Detection Device) As schematically shown in FIGS. 1A and 1B, the position detection device 9 according to the first embodiment includes a magnetic scale 8 and a magnetic sensor 1.

[0012] In the magnetic scale 8, N poles 81 and S poles 82 are alternately magnetized in a predetermined direction D1. In the predetermined direction D1, the distance between the centers of two adjacent N poles 81 and the distance between the centers of two adjacent S poles 82 are the same as each other.

[0013] (Magnetic Sensor) The magnetic sensor 1 is configured to detect the position of a detection target based on a change in the magnetic field strength generated by the relative movement of the detection target in a predetermined direction D1. In the position detection device 9 according to the first embodiment, the magnetic scale 8 constitutes the detection target.

[0014] In the position detection device 9 according to the first embodiment, the magnetic sensor 1 is formed long in the predetermined direction D1. That is, the longitudinal direction of the magnetic sensor 1 is the predetermined direction D1.

[0015] The magnetic sensor 1 includes a magnetoresistive element group 2 for relative position detection shown in FIG. 2 and a magnetoresistive element group 3 for origin detection. In the position detection device 9 according to the first embodiment, the magnetic sensor 1 is provided with a pair of magnetoresistive element groups 3 for origin detection.

[0016] Hereinafter, one of the pair of magnetoresistive element groups 3 for origin detection is labeled with reference numeral 3A, and the other is labeled with reference numeral 3B.

[0017] The pair of magnetoresistive element groups 3A and 3B for origin detection are located on both sides sandwiching the magnetoresistive element group 2 for relative position detection in a predetermined direction D1. In other words, the magnetoresistive element group 2 for relative position detection is located between the pair of magnetoresistive element groups 3A and 3B in the predetermined direction D1.

[0018] (Magnetoresistive element group for relative position detection) The magnetoresistive element group 2 for relative position detection is arranged in a predetermined direction D1 in order to detect the relative position of the magnetic scale 8 that is the detection target.

[0019] Specifically, the magnetoresistive element group 2 for relative position detection is composed of a plurality of magnetoresistive elements 41 - 44 arranged in the predetermined direction D1. The plurality of magnetoresistive elements 41 - 44 are electrically connected so as to form a full - bridge circuit. In the magnetic sensor 1 of the first embodiment, the plurality of magnetoresistive elements 41 - 44 are four magnetoresistive elements 41 - 44 arranged in the predetermined direction D1. The four magnetoresistive elements 41 - 44 are composed of a first magnetoresistive element 41, a second magnetoresistive element 42, a third magnetoresistive element 43, and a fourth magnetoresistive element 44.

[0020] The magnetic sensor 1 of the first embodiment includes a first wiring pattern 51, a second wiring pattern 52, a third wiring pattern 53, and a fourth wiring pattern 54.

[0021] Also, the magnetic sensor 1 of the first embodiment includes a ground terminal 61, a power supply terminal 62, a first output terminal 63, and a second output terminal 64.

[0022] The first magnetoresistive element 41, the second magnetoresistive element 42, the third magnetoresistive element 43, and the fourth magnetoresistive element 44 form a full-bridge circuit. Specifically, a series circuit of the first magnetoresistive element 41 and the second magnetoresistive element 42 and a series circuit of the third magnetoresistive element 43 and the fourth magnetoresistive element 44 are connected in parallel to each other. That is, the four magnetoresistive elements 41 - 44 include the first magnetoresistive element 41 and the second magnetoresistive element 42 connected in series with each other, and the third magnetoresistive element 43 and the fourth magnetoresistive element 44 connected in series with each other.

[0023] The connection point P1 between the first magnetoresistive element 41 and the second magnetoresistive element 42 is connected to the ground terminal 61 via the first wiring pattern 51. In other words, the connection point P1 between the first magnetoresistive element 41 and the second magnetoresistive element 42 is the ground connection point 71.

[0024] The connection point P2 between the third magnetoresistive element 43 and the fourth magnetoresistive element 44 is connected to the power supply terminal 62 via the second wiring pattern 52. In other words, the connection point P2 between the third magnetoresistive element 43 and the fourth magnetoresistive element 44 is the power supply connection point 72.

[0025] The connection point P3 between the second magnetoresistive element 42 and the fourth magnetoresistive element 44 is connected to the first output terminal 63 via the third wiring pattern 53. In other words, the connection point P3 between the second magnetoresistive element 42 and the fourth magnetoresistive element 44 is the first output connection point 73.

[0026] The connection point P4 between the first magnetoresistive element 41 and the third magnetoresistive element 43 is connected to the second output terminal 64 via the fourth wiring pattern 54. In other words, the connection point P4 between the first magnetoresistive element 41 and the third magnetoresistive element 43 is the second output connection point 74.

[0027] (Magnetoresistive element group for origin detection) The magnetoresistive element groups 3A and 3B for origin detection are each arranged in a predetermined direction D1 in order to detect the origin of the magnetic scale 8 to be detected.

[0028] Specifically, the magnetoresistive element group 3A for origin detection is composed of a plurality of magnetoresistive elements 45 and 46 arranged in a predetermined direction D1. The plurality of magnetoresistive elements 45 and 46 are electrically connected in series.

[0029] In the magnetic sensor 1 of the first embodiment, the plurality of magnetoresistive elements 45 and 46 are two magnetoresistive elements 45 and 46 arranged in a predetermined direction D1. The two magnetoresistive elements 45 and 46 are composed of a fifth magnetoresistive element 45 and a sixth magnetoresistive element 46 that are electrically connected in series.

[0030] The fifth magnetoresistive element 45 has a first end portion electrically connected to the sixth magnetoresistive element 46 and a second end portion on the opposite side. A power supply terminal 67 is electrically connected to the second end portion of the fifth magnetoresistive element 45.

[0031] The sixth magnetoresistive element 46 has a first end portion electrically connected to the fifth magnetoresistive element 45 and a second end portion on the opposite side. The first end portion of the sixth magnetoresistive element 46 is electrically connected to the first end portion of the fifth magnetoresistive element 45 via a fifth wiring pattern 55. A third output terminal 65 is electrically connected to the fifth wiring pattern 55. The second end portion of the sixth magnetoresistive element 46 is electrically connected to the ground terminal 61.

[0032] That is, the ground terminal 61 is electrically connected to the magnetoresistive element group 2 for relative position detection and the magnetoresistive element group 3A for origin detection.

[0033] More specifically, the connection point P1 between the first magnetoresistive element 41 and the second magnetoresistive element 42 included in the magnetoresistive element group 2 for relative position detection is electrically connected to the ground terminal 61. In addition, the sixth magnetoresistive element 46 included in the magnetoresistive element group 3A for origin detection is electrically connected to the ground terminal 61. The ground terminal 61 is shared by the magnetoresistive element group 2 for relative position detection and the magnetoresistive element group 3A for origin detection.

[0034] The group of magnetoresistive elements 3B for origin detection is composed of a plurality of magnetoresistive elements 47 and 48 arranged in a predetermined direction D1. The plurality of magnetoresistive elements 47 and 48 are electrically connected in series.

[0035] In the magnetic sensor 1 of the first embodiment, the plurality of magnetoresistive elements 47 and 48 are two magnetoresistive elements 47 and 48 arranged in a predetermined direction D1. The two magnetoresistive elements 47 and 48 are composed of a seventh magnetoresistive element 47 and an eighth magnetoresistive element 48 that are electrically connected in series.

[0036] The seventh magnetoresistive element 47 has a first end electrically connected to the eighth magnetoresistive element 48 and a second end on the opposite side. A power supply terminal 68 is electrically connected to the second end of the seventh magnetoresistive element 47.

[0037] The eighth magnetoresistive element 48 has a first end electrically connected to the seventh magnetoresistive element 47 and a second end on the opposite side. The first end of the eighth magnetoresistive element 48 is electrically connected to the first end of the seventh magnetoresistive element 47 via a sixth wiring pattern 56. A fourth output terminal 66 is electrically connected to the sixth wiring pattern 56. A ground terminal 69 is electrically connected to the second end of the eighth magnetoresistive element 48.

[0038] That is, in the magnetic sensor 1 of the first embodiment, the ground terminal 61 electrically connected to the group of magnetoresistive elements 2 for relative position detection and the ground terminal 69 electrically connected to the group of magnetoresistive elements 3B for origin detection are provided independently of each other.

[0039] The signal output from the third output terminal 65 becomes a signal close to the signals output from the first output terminal 63 and the second output terminal 64, but includes a component resulting from the presence of one end of the magnetic scale 8. Therefore, by taking the difference between the output signals from the first output terminal 63 and the second output terminal 64 and the output signal from the third output terminal 65, it is possible to detect the presence of one end of the magnetic scale 8. Similarly, by taking the difference between the output signals from the first output terminal 63 and the second output terminal 64 and the output signal from the fourth output terminal 66, it is possible to detect the presence of the other end of the magnetic scale 8.

[0040] (Sharing of terminals) As described above, in the magnetic sensor 1 of the first embodiment, the magnetoresistive element group 2 for relative position detection and the magnetoresistive element group 3A for origin detection located adjacent thereto share the ground terminal 61.

[0041] Therefore, the magnetic sensor 1 of the first embodiment is provided with nine terminals 61 - 69. The nine terminals 61 - 69 are the ground terminal 61, the power supply terminal 62, the first output terminal 63, the second output terminal 64, the third output terminal 65, the fourth output terminal 66, the power supply terminal 67, the power supply terminal 68, and the ground terminal 69.

[0042] Fig. 3 shows a comparative example. In the comparative example, the same reference numerals are given to the same configurations as those in the first embodiment. In the magnetic sensor 1 of the comparative example, the ground terminal 61 is not shared between the magnetoresistive element group 2 for relative position detection and the magnetoresistive element group 3A for origin detection. A ground terminal 60 different from the ground terminal 61 is electrically connected to the second end of the sixth magnetoresistive element 46 included in the magnetoresistive element group 3A for origin detection. The magnetic sensor 1 of the modified example is provided with ten terminals 60 - 69.

[0043] As is clear from the comparison with the above-described comparative example, as in the magnetic sensor 1 of the first embodiment, one of the magnetoresistive element groups 3A and 3B for origin detection (here, the magnetoresistive element group 3A) shares the ground terminal 61 with the magnetoresistive element group 2 for relative position detection, so that the number of terminals is reduced by one. Therefore, according to the magnetic sensor 1 of the first embodiment, it is possible to reduce the chip size, and thus it is possible to reduce the size of the magnetic sensor 1 and, consequently, the size of the position detection device 9.

[0044] 2. Second Embodiment The position detection device 9 and the magnetic sensor 1 of the second embodiment will be described with reference to FIGS. 4 and 5. In the position detection device 9 and the magnetic sensor 1 of the second embodiment, the power supply terminal 62 is shared between the magnetoresistive element group 2 for relative position detection and the magnetoresistive element group 3B for origin detection included in the magnetic sensor 1, and in this respect, it is different from the position detection device 9 and the magnetic sensor 1 of the first embodiment.

[0045] Except for the above differences, the position detection device 9 and the magnetic sensor 1 of the second embodiment have the same configuration as the first embodiment. For the same configuration as the first embodiment, the same reference numerals are given and the detailed description is omitted.

[0046] As shown in FIG. 4, in the magnetic sensor 1 of the third embodiment, the seventh magnetoresistive element 47 has a first end portion electrically connected to the eighth magnetoresistive element 48 and a second end portion on the opposite side, and the second end portion of the seventh magnetoresistive element 47 is electrically connected to the power supply terminal 62.

[0047] That is, the power supply terminal 62 is electrically connected to the magnetoresistive element group 2 for relative position detection and the magnetoresistive element group 3B for origin detection.

[0048] More specifically, the connection point P2 between the third magnetoresistive element 43 and the fourth magnetoresistive element 44 included in the magnetoresistive element group 2 for relative position detection is electrically connected to the power supply terminal 62. In addition, the seventh magnetoresistive element 47 included in the magnetoresistive element group 3B for origin detection is electrically connected to the power supply terminal 62. The power supply terminal 62 is shared by the magnetoresistive element group 2 for relative position detection and the magnetoresistive element group 3B for origin detection.

[0049] That is, in the magnetic sensor 1 of the second embodiment, the ground terminal 61 is shared by the magnetoresistive element group 2 for relative position detection and the magnetoresistive element group 3A for origin detection, and the power supply terminal 62 is shared by the magnetoresistive element group 2 for relative position detection and the magnetoresistive element group 3B for origin detection.

[0050] Therefore, for example, when compared with the comparative example shown in FIG. 3, the number of terminals is reduced by two.

[0051] FIG. 5 shows the appearance of the magnetic sensor 1 of the second embodiment. The magnetic sensor 1 of the second embodiment includes a support substrate 10 having a longitudinal direction in a predetermined direction D1, and a plurality of electrodes 11-18 provided on the surface of the support substrate 10. The support substrate 10 is, for example, a ceramic substrate. The material of the plurality of electrodes 11-18 is, for example, a CuNi (copper nickel) based alloy.

[0052] The plurality of electrodes 11-18 are eight electrodes 11-18. The eight electrodes 11-18 are electrically connected one-to-one to the eight terminals 61-67, 69 shown in FIG. 4. The eight terminals 61-67, 69 are the ground terminal 61, the power supply terminal 62, the first output terminal 63, the second output terminal 64, the third output terminal 65, the fourth output terminal 66, the power supply terminal 67, and the ground terminal 69.

[0053] According to the magnetic sensor 1 of the second embodiment, the chip size can be reduced, and the magnetic sensor 1 can be miniaturized, and thus the position detection device 9 can be miniaturized.

[0054] 3. Third Embodiment The position detection device 9 and the magnetic sensor 1 according to the third embodiment will be described with reference to FIGS. 6 to 8. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

[0055] Also in the magnetic sensor 1 according to the third embodiment, eight magnetoresistive elements 41 - 48 arranged in a predetermined direction D1 are provided, and these eight magnetoresistive elements 41 - 48 constitute a magnetoresistive element group 2 for relative position detection and a pair of magnetoresistive element groups 3A and 3B for origin detection.

[0056] In the magnetic sensor 1 according to the third embodiment, the eight magnetoresistive elements 41 - 48 are electrically connected so as to form a full - bridge circuit.

[0057] The eight magnetoresistive elements 41 - 48 are composed of four magnetoresistive elements 41 - 44 arranged in a predetermined direction D1 and two pairs of magnetoresistive elements 45 - 48 located on both sides sandwiching the four magnetoresistive elements 41 - 44 in the predetermined direction D1.

[0058] The four magnetoresistive elements 41 - 44 are the first magnetoresistive element 41, the second magnetoresistive element 42, the third magnetoresistive element 43, and the fourth magnetoresistive element 44, which are arranged in the predetermined direction D1 in this order. The pair of magnetoresistive elements 45, 46 are the fifth magnetoresistive element 45 and the sixth magnetoresistive element 46, which are arranged in the predetermined direction D1 in this order. The sixth magnetoresistive element 46 is arranged adjacent to the first magnetoresistive element 41 in the predetermined direction D1. The other pair of magnetoresistive elements 47, 48 are the seventh magnetoresistive element 47 and the eighth magnetoresistive element 48, which are arranged in the predetermined direction D1 in this order. The seventh magnetoresistive element 47 is arranged adjacent to the fourth magnetoresistive element 44 in the predetermined direction D1. That is, the fifth magnetoresistive element 45, the sixth magnetoresistive element 46, the first magnetoresistive element 41, the second magnetoresistive element 42, the third magnetoresistive element 43, the fourth magnetoresistive element 44, the seventh magnetoresistive element 47, and the eighth magnetoresistive element 48 are arranged in the predetermined direction D1 in this order.

[0059] Among the four magnetoresistive elements 41 - 44, the first magnetoresistive element 41 and the third magnetoresistive element 43 are electrically connected, and the second magnetoresistive element 42 and the fourth magnetoresistive element 44 are electrically connected.

[0060] Also, the first magnetoresistive element 41 is electrically connected to the fifth magnetoresistive element 45, and the second magnetoresistive element 42 is electrically connected to the sixth magnetoresistive element 46. The fifth magnetoresistive element 45 and the sixth magnetoresistive element 46 are electrically connected.

[0061] The third magnetoresistive element 43 is electrically connected to the seventh magnetoresistive element 47, and the fourth magnetoresistive element 44 is electrically connected to the eighth magnetoresistive element 48. The seventh magnetoresistive element 47 and the eighth magnetoresistive element 48 are electrically connected.

[0062] In the full - bridge circuit including these eight magnetoresistive elements 41 - 48, a ground connection point 71, a power supply connection point 72, a first output connection point 73, a second output connection point 74, a third output connection point 75, and a fourth output connection point 76 are provided.

[0063] A ground terminal 61 is electrically connected to the ground connection point 71. The ground connection point 71 is constituted by the connection point P5 between the fifth magnetoresistive element 45 and the sixth magnetoresistive element 46.

[0064] A power supply terminal 62 is electrically connected to the power supply connection point 72. The power supply connection point 72 is constituted by the connection point P6 between the seventh magnetoresistive element 47 and the eighth magnetoresistive element 48.

[0065] A first output terminal 63 is electrically connected to the first output connection point 73. The first output connection point 73 is constituted by the connection point P3 between the second magnetoresistive element 42 and the fourth magnetoresistive element 44.

[0066] A second output terminal 64 is electrically connected to the second output connection point 74. The second output connection point 74 is constituted by the connection point P4 between the first magnetoresistive element 41 and the third magnetoresistive element 43.

[0067] The third output connection point 75 is electrically connected to the third output terminal 65 for origin detection. The third output connection point 75 is constituted by the connection point P7 between the first magnetoresistive element 41 and the fifth magnetoresistive element 45.

[0068] The fourth output connection point 76 is electrically connected to the fourth output terminal 66 for origin detection. The fourth output connection point 76 is constituted by the connection point P8 between the fourth magnetoresistive element 44 and the eighth magnetoresistive element 48.

[0069] In the magnetic sensor 1 of the third embodiment, the ground terminal 61 and the power supply terminal 62 are shared by the magnetoresistive element group 2 for relative position detection and the magnetoresistive element groups 3A and 3B for origin detection. Therefore, for example, when compared with the comparative example shown in FIG. 3, the number of terminals is reduced by four.

[0070] FIG. 8 shows the appearance of the magnetic sensor 1 of the third embodiment. The magnetic sensor 1 of the third embodiment includes six electrodes 11 - 16 provided on the surface of the support substrate 10. The material of the six electrodes 11 - 16 is, for example, a CuNi (copper nickel) - based alloy.

[0071] The six electrodes 11 - 16 are electrically connected one - to - one to the six terminals 61 - 66 shown in FIG. 7. The six terminals 61 - 66 are the ground terminal 61, the power supply terminal 62, the first output terminal 63, the second output terminal 64, the third output terminal 65, and the fourth output terminal 66.

[0072] According to the magnetic sensor 1 of the third embodiment, the chip size can be reduced, and thus the magnetic sensor 1 can be miniaturized, and further the position detection device 9 can be miniaturized.

[0073] It is preferable that the plurality of magnetoresistive elements 41 - 48 are each formed in a meander shape. As shown in FIG. 7, in the magnetic sensor 1 of the third embodiment, the eight magnetoresistive elements 41 - 48 are each formed in a meander shape in a plan view.

[0074] The first to fourth magnetoresistive elements 41-44 having a meander shape are arranged in a predetermined direction D1 with a gap of uniform width therebetween. Similarly, the fifth and sixth magnetoresistive elements 45, 46 having a meander shape are arranged in a predetermined direction D1 with a gap of uniform width therebetween, and the seventh and eighth magnetoresistive elements 47, 48 having a meander shape are arranged in a predetermined direction D1 with a gap of uniform width therebetween. The sixth magnetoresistive element 46 and the first magnetoresistive element 41 are arranged in a predetermined direction D1 with a gap of relatively large width therebetween, and the fourth magnetoresistive element 44 and the seventh magnetoresistive element 47 are arranged in a predetermined direction D1 with a gap of relatively large width therebetween. The width in the predetermined direction D1 between the sixth magnetoresistive element 46 and the first magnetoresistive element 41 is the same as the width in the predetermined direction D1 between the seventh magnetoresistive element 47 and the fourth magnetoresistive element 44.

[0075] In the first and second embodiments as well, it is preferable that each of the plurality of magnetoresistive elements 41-48 is formed in a meander shape. Note that it is also possible to provide these plurality of magnetoresistive elements 41-48 in a shape other than the meander shape.

[0076] 4. Modifications The above-described embodiments are merely one of various embodiments of the present disclosure. The above-described embodiments can be variously modified according to design and the like as long as the object of the present disclosure can be achieved. Hereinafter, modifications of the above-described embodiments will be listed. The modifications described below can be applied in appropriate combinations.

[0077] In the magnetic sensor 1 of the first embodiment, the ground terminal 61 is shared by the magnetoresistive element group 2 for relative position detection and the magnetoresistive element group 3A for origin detection, but the shared terminal is not limited to this. For example, it is also possible to share the power supply terminal 62 by the magnetoresistive element group 2 for relative position detection and the magnetoresistive element group 3A for origin detection.

[0078] In the magnetic sensor 1 of the second embodiment, the magnetic resistance element group 2 for relative position detection and the magnetic resistance element group 3A for origin detection share the ground terminal 61, and the magnetic resistance element group 2 for relative position detection and the magnetic resistance element group 3B for origin detection share the power supply terminal 62. However, the shared terminals are not limited to these. For example, it is also possible that the magnetic resistance element group 2 for relative position detection and the magnetic resistance element group 3A for origin detection share the power supply terminal 62, and the magnetic resistance element group 2 for relative position detection and the magnetic resistance element group 3B for origin detection share the ground terminal 61. The magnetic resistance element group 2 for relative position detection and the magnetic resistance element group 3A for origin detection do not share either the ground terminal 61 or the power supply terminal 62, and it is also possible that the magnetic resistance element group 2 for relative position detection and the magnetic resistance element group 3B for origin detection share at least one of the ground terminal 61 and the power supply terminal 62. Also, the magnetic resistance element group 2 for relative position detection and the magnetic resistance element group 3B for origin detection do not share either the ground terminal 61 or the power supply terminal 62, and it is also possible that the magnetic resistance element group 2 for relative position detection and the magnetic resistance element group 3A for origin detection share at least one of the ground terminal 61 and the power supply terminal 62.

[0079] In the above embodiment, as the magnetic resistance element group 3 for detecting the origin of the detection target, a pair of magnetic resistance element groups 3A and 3B for origin detection are provided, but it is also possible to provide only one magnetic resistance element group 3. For example, in the magnetic sensor 1 of the first embodiment, it is also possible to provide only the magnetic resistance element group 3A for origin detection as the magnetic resistance element group 3 for detecting the origin of the detection target.

[0080] 5. Summary As described based on the above embodiments and modifications, the magnetic sensor (1) of the first aspect is a magnetic sensor (1) configured to detect the position of a detection target based on a change in magnetic field strength generated by the relative movement of the detection target in a predetermined direction (D1). The magnetic sensor (1) includes a magnetic resistance element group (2) for relative position detection arranged in the predetermined direction (D1) to detect the relative position of the detection target, and a magnetic resistance element group (3) for origin detection arranged in the predetermined direction (D1) to detect the origin of the detection target. The magnetic resistance element group (2) for relative position detection and the magnetic resistance element group (3) for origin detection share at least one of the ground terminal (61) and the power supply terminal (62).

[0081] According to this aspect, since at least one of the ground terminal (61) and the power supply terminal (62) is shared by the magnetic resistance element group (2) for relative position detection and the magnetic resistance element group (3) for origin detection, the chip size can be reduced. Therefore, the size of the magnetic sensor (1) can be reduced.

[0082] The magnetic sensor (1) of the second aspect has, in the first aspect, a pair of magnetic resistance element groups (3) for origin detection. One of the pair of magnetic resistance element groups (3) for origin detection shares the ground terminal (61) or the power supply terminal (62) with the magnetic resistance element group (2) for relative position detection.

[0083] According to this aspect, the origin of the detection target can be detected by using the pair of magnetic resistance element groups (3) for origin detection, and moreover, the increase in the size of the magnetic sensor (1) can be suppressed.

[0084] The magnetic sensor (1) of the third aspect has a pair of magnetic resistance element groups (3) for origin detection. One of the pair of magnetic resistance element groups (3) for origin detection shares the ground terminal (61) with the magnetic resistance element group (2) for relative position detection. The other of the pair of magnetic resistance element groups (3) for origin detection shares the power supply terminal (62) with the magnetic resistance element group (2) for relative position detection.

[0085] According to this aspect, the origin of the detection target can be detected by using a pair of magnetoresistive element groups (3) for origin detection, and moreover, the increase in size of the magnetic sensor (1) can be suppressed.

[0086] In the magnetic sensor (1) of the fourth aspect, in the second or third aspect, the magnetoresistive element group (2) for relative position detection is composed of four magnetoresistive elements (41 - 44) electrically connected so as to form a full bridge circuit.

[0087] The magnetic sensor (1) of the fifth aspect includes a pair of magnetoresistive element groups (3) for origin detection. The magnetoresistive element group (2) for relative position detection and the pair of magnetoresistive element groups (3) for origin detection are composed of eight magnetoresistive elements (41 - 48) arranged in a predetermined direction (D1) and electrically connected so as to form a full bridge circuit.

[0088] According to this aspect, the relative position can be accurately detected by using eight magnetoresistive elements (41 - 48), and moreover, the increase in size of the magnetic sensor (1) can be suppressed.

[0089] In the magnetic sensor (1) of the sixth aspect, in the fifth aspect, the eight magnetoresistive elements (41 - 48) each have a meander shape.

[0090] According to this aspect, the effective length of the magnetoresistive elements (41 - 48) can be increased within a limited range.

[0091] In the magnetic sensor (1) of the seventh aspect, in the sixth aspect, the full bridge circuit is provided with one ground connection point (71) to which the ground terminal (61) is electrically connected and one power supply connection point (72) to which the power supply terminal (62) is electrically connected.

[0092] According to this aspect, since there is one ground connection point (71) and one power supply connection point (72) connected to the full bridge circuit respectively, the increase in size of the magnetic sensor (1) can be suppressed.

[0093] The position detection device (9) according to the eighth aspect includes any one of the magnetic sensors (1) according to the first to seventh aspects and a magnetic scale (8) in which N poles (81) and S poles (82) are alternately magnetized in a predetermined direction. The magnetic scale (8) constitutes a detection target.

[0094] According to this aspect, since at least one of the ground terminal (61) and the power supply terminal (62) is shared by the magnetoresistive element group (2) for relative position detection and the magnetoresistive element group (3) for origin detection, the chip size can be reduced. Therefore, the magnetic sensor (1) and thus the position detection device (9) can be miniaturized.

Explanation of Signs

[0095] 1 Magnetic sensor 2 Magnetoresistive element group for relative position detection 3 Magnetoresistive element group for origin detection 41 Magnetoresistive element (first magnetoresistive element) 42 Magnetoresistive element (second magnetoresistive element) 43 Magnetoresistive element (third magnetoresistive element) 44 Magnetoresistive element (fourth magnetoresistive element) 45 Magnetoresistive element (fifth magnetoresistive element) 46 Magnetoresistive element (sixth magnetoresistive element) 47 Magnetoresistive element (seventh magnetoresistive element) 48 Magnetoresistive element (eighth magnetoresistive element) 61 Ground terminal 62 Power supply terminal 71 Ground connection point 72 Power supply connection point 8 Magnetic scale 81 N pole 82 S pole 9 Position detection device

Claims

1. A magnetic sensor configured to detect the position of a detection target based on a change in magnetic field strength generated by relative movement of the detection target in a predetermined direction, comprising: a group of magnetoresistive elements for relative position detection arranged in the predetermined direction to detect the relative position of the detection target; a group of magnetoresistive elements for origin detection arranged in the predetermined direction to detect the origin of the detection target; and the group of magnetoresistive elements for relative position detection and the group of magnetoresistive elements for origin detection share at least one of a ground terminal and a power supply terminal. Magnetic sensor.

2. Comprising a pair of groups of magnetoresistive elements for origin detection, wherein one of the pair of groups of magnetoresistive elements for origin detection shares the ground terminal or the power supply terminal with the group of magnetoresistive elements for relative position detection. The magnetic sensor according to Claim 1.

3. Comprising a pair of groups of magnetoresistive elements for origin detection, wherein one of the pair of groups of magnetoresistive elements for origin detection shares the ground terminal with the group of magnetoresistive elements for relative position detection, and the other of the pair of groups of magnetoresistive elements for origin detection shares the power supply terminal with the group of magnetoresistive elements for relative position detection. The magnetic sensor according to Claim 1.

4. The group of magnetoresistive elements for relative position detection is composed of four magnetoresistive elements electrically connected to form a full bridge circuit. The magnetic sensor according to Claim 2 or 3.

5. Comprising a pair of groups of magnetoresistive elements for origin detection, wherein the group of magnetoresistive elements for relative position detection and the pair of groups of magnetoresistive elements for origin detection are composed of eight magnetoresistive elements arranged in the predetermined direction and electrically connected to form a full bridge circuit. The magnetic sensor according to Claim 1.

6. Each of the eight magnetoresistive elements has a meander shape. The magnetic sensor according to Claim 5.

7. The full bridge circuit is provided with one ground connection point to which the ground terminal is electrically connected and one power supply connection point to which the power supply terminal is electrically connected. The magnetic sensor according to Claim 6.

8. The magnetic sensor according to Claim 1, and a magnetic scale in which N poles and S poles are alternately magnetized in the predetermined direction, wherein the magnetic scale constitutes the detection target. Position detection device.

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