Magnetic Sensor

Abstract

To provide a magnetic sensor with which a variation in detection sensitivity is small and high detection sensitivity can be obtained.SOLUTION: A magnetic sensor 1 includes a sensor chip 100, and external magnetic bodies 10, 20 the longitudinal direction of which is a direction x. On an element forming surface 105 of the sensor chip 100 are formed magnetic body layers 111, 112 arrayed in the direction x via a magnetic gap G2 and a magneto-sensitive element R1 a magnetro sensitive direction of which is the direction x. The external magnetic body 10 includes an inner surface 12a that covers the element forming surface 105 so as to overlap the magnetic body layer 111 and an inner surface 11a that covers a side surface 101, and the external magnetic body 20 includes an inner surface 22a that covers the element forming surface 105 so as to overlap the magnetic body layer 112 and an inner surface 21a that covers a side surface 102. Thus, as the external magnetic bodies 10, 20 can be located in position by the side surfaces 101, 102 of the sensor chip 100, a variation in detection sensitivity hardly occurs.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to a magnetic sensor, and more particularly to a magnetic sensor having an external magnetic body that collects magnetic flux in a magnetic sensing element. [Background technology]

[0002] Patent Document 1 discloses a magnetic sensor equipped with an external magnetic body that collects magnetic flux in a magnetic sensing element. The magnetic sensor described in Patent Document 1 collects vertical magnetic flux using the external magnetic body and bends the collected magnetic flux horizontally to detect the horizontal component of the magnetic flux. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5297442 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the magnetic sensor described in Patent Document 1 detects the horizontal component of magnetic flux by bending the vertical magnetic flux, so the magnetic flux component that contributes to sensitivity is small, making it difficult to obtain high detection sensitivity. In addition, there is also a problem that the detection sensitivity changes significantly depending on the position of the external magnetic body.

[0005] SUMMARY OF THE PRESENT EMBODIMENTS Accordingly, an object of the present invention is to provide a magnetic sensor that has little variation in detection sensitivity and is capable of achieving high detection sensitivity. [Means for solving the problem]

[0006] The magnetic sensor according to the present invention comprises a first sensor chip having an element forming surface extending in a first direction and a second direction perpendicular to the first direction, and first and second side surfaces perpendicular to the first direction and parallel to each other, and first and second external magnetic bodies having the first direction as its longitudinal direction, and on the element forming surface, first and second magnetic layers arranged in the first direction via a first magnetic gap, and a first magnetic sensing element arranged on a magnetic path formed by the first magnetic gap and having the first direction as its magnetic sensing direction are formed, the first external magnetic body having a first inner surface covering the element forming surface so as to overlap with the first magnetic layer and a second inner surface covering the first side surface, and the second external magnetic body having a third inner surface covering the element forming surface so as to overlap with the second magnetic layer, and a fourth inner surface covering the second side surface.

[0007] According to the present invention, the magnetic flux collected by the first and second external magnetic bodies, which have a longitudinal direction in the first direction, is applied to the magnetic sensing element, which has a magnetic sensing direction in the first direction, so that many magnetic flux components contribute to sensitivity, and thus it is possible to obtain high detection sensitivity. Moreover, since the first and second external magnetic bodies can be positioned by the first and second side surfaces of the sensor chip, the mounting positions of the first and second external magnetic bodies are unlikely to shift, and therefore the detection sensitivity is unlikely to vary.

[0008] In the present invention, the first inner surface of the first external magnetic body and the third inner surface of the second external magnetic body may have a shape in which the width in the second direction becomes narrower toward the first magnetic gap, which makes it possible to further increase the density of the magnetic flux applied to the magnetic sensing element.

[0009] In the present invention, the first external magnetic body may have a structure in which a corner where the first inner surface and the second inner surface meet is removed, and the second external magnetic body may have a structure in which a corner where the third inner surface and the fourth inner surface meet is removed, thereby improving the positioning accuracy of the first and second external magnetic bodies using the first and second side surfaces.

[0010] The magnetic sensor according to the present invention may further include a substrate on which the first sensor chip, the first external magnetic body, and the second external magnetic body are mounted, and the first sensor chip may be mounted such that a third side surface perpendicular to the second direction faces the substrate. This allows the first and second external magnetic bodies to be stably supported even if they are long, and also makes it possible to shorten the length of the wiring connecting the first sensor chip and the substrate.

[0011] The magnetic sensor according to the present invention may further include an auxiliary substrate mounted on the substrate and disposed on the back surface of the first sensor chip opposite the element forming surface thereof. This increases the mechanical strength of the first sensor chip even if the first sensor chip is thin, thereby making it possible to prevent the first sensor chip from being damaged.

[0012] The magnetic sensor according to the present invention further comprises a second sensor chip having an element forming surface extending in a first and second direction and fourth and fifth side surfaces perpendicular to the first direction and parallel to each other, and third and fourth external magnetic bodies having the first direction as a longitudinal direction, and on the element forming surface of the second sensor chip, third and fourth magnetic layers arranged in the first direction via a second magnetic gap and a second magnetic sensing element arranged on a magnetic path formed by the second magnetic gap and having the first direction as a magnetic sensing direction are formed, the third external magnetic body has a fifth inner surface covering the element forming surface so as to overlap with the third magnetic layer and a sixth inner surface covering the fourth side surface, the fourth external magnetic body has a seventh inner surface covering the element forming surface so as to overlap with the fourth magnetic layer and an eighth inner surface covering the fifth side surface, and the sensitivity axis directions of the first magnetic sensing element and the second magnetic sensing element may differ from each other by 180°. This makes it possible to obtain a differential signal from the first and second magneto-sensitive elements.

[0013] In this case, the first sensor chip and the second sensor chip may be arranged so that the rear surfaces opposite to the element formation surface face each other. This makes it possible to use the first and second sensor chips having the same structure. Furthermore, in this case, a spacer may be further provided in contact with the rear surface of the first sensor chip and the rear surface of the second sensor chip, or the rear surface of the first sensor chip and the rear surface of the second sensor chip may be in contact with each other. This makes it possible to reduce the temperature difference between the first sensor chip and the second sensor chip. Effect of the Invention

[0014] As described above, according to the present invention, it is possible to provide a magnetic sensor that has little variation in detection sensitivity and is capable of achieving high detection sensitivity. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic perspective view showing the appearance of a magnetic sensor 1 according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic partial perspective view of the magnetic sensor 1 as viewed from a different angle. [Diagram 3] FIG. 3 is a schematic exploded perspective view of the magnetic sensor 1. As shown in FIG. [Figure 4] FIG. 4 is a schematic exploded perspective view of the magnetic sensor 1. As shown in FIG. [Diagram 5] FIG. 5 is a schematic partial perspective view showing an example in which an auxiliary substrate 120 is added to the magnetic sensor 1. As shown in FIG. [Figure 6] FIG. 6 is a schematic perspective view for explaining the structure of the sensor chip 100. As shown in FIG. [Figure 7] FIG. 7 is a schematic perspective view showing the sensor chip 100 with the magnetic layers 111 and 112 removed. [Figure 8] FIG. 8 is an xz cross-sectional view of a main part of the sensor chip 100. As shown in FIG. [Figure 9] FIG. 9 is a schematic partial perspective view showing an enlarged view of a main part of the magnetic sensor 1. As shown in FIG. [Figure 10]FIG. 10 is a graph showing the relationship between the width of the magnetic gap G1 and the thickness of the protrusions 12 and 22 in the z direction and the magnetic flux density applied to the magnetic sensing element R1. [Figure 11] FIG. 11(a) is a circuit diagram showing a circuit for obtaining a detection signal V1, and FIG. 11(b) is a circuit diagram showing a circuit for obtaining detection signals V2 and V3. [Figure 12] FIG. 12 is a schematic perspective view showing the appearance of a magnetic sensor 2 according to the second embodiment of the present invention. [Figure 13] FIG. 13 is a schematic exploded perspective view of a portion of the magnetic sensor 2. As shown in FIG. [Figure 14] FIG. 14 is a schematic exploded perspective view of a portion of the magnetic sensor 2. As shown in FIG. [Figure 15] FIG. 15(a) is a circuit diagram showing a circuit for obtaining a detection signal V4, and FIG. 15(b) is a circuit diagram showing a circuit for obtaining differential signals V5 and V6. [Figure 16] FIG. 16 is a schematic partial perspective view showing an example in which a spacer 300 is added to the magnetic sensor 2. As shown in FIG. [Figure 17] FIG. 17 is a schematic perspective view showing the appearance of a magnetic sensor 3 according to the third embodiment of the present invention. [Figure 18] FIG. 18 is a schematic exploded perspective view of a part of the magnetic sensor 3. As shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0017] Fig. 1 is a schematic perspective view showing the appearance of a magnetic sensor 1 according to a first embodiment of the present invention. Fig. 2 is a schematic partial perspective view of the magnetic sensor 1 seen from a different angle, and Figs. 3 and 4 are schematic exploded perspective views of the magnetic sensor 1.

[0018] As shown in Figs. 1 to 4, the magnetic sensor 1 according to the first embodiment includes a substrate 8, and a sensor chip 100 and external magnetic bodies 10, 20 mounted on the substrate 8. The substrate 8 has an xz plane as its main surface, and the sensor chip 100 and external magnetic bodies 10, 20 are mounted on the main surface. The sensor chip 100 has side surfaces 101, 102 that form a yz plane and are located opposite each other, side surfaces 103, 104 that form an xz plane and are located opposite each other, and an element forming surface 105 and a back surface 106 that form an xy plane and are located opposite each other. The sensor chip 100 is mounted upright on the substrate 8 so that the side surface 103 faces the main surface of the substrate 8.

[0019] Both of the external magnetic bodies 10 and 20 are made of a high magnetic permeability material such as ferrite. The external magnetic body 10 is made of a rod-shaped main body 11 whose longitudinal direction is the x direction, and a protruding part 12 provided at the end of the main body 11 in the x direction. Similarly, the external magnetic body 20 is made of a rod-shaped main body 21 whose longitudinal direction is the x direction, and a protruding part 22 provided at the end of the main body 21 in the x direction. The main body 11 and the protruding part 12 may be integral with each other, or may each be made of a separate block. The same applies to the main body 21 and the protruding part 22.

[0020] The thickness of the protrusions 12, 22 in the z direction is thinner than the thickness of the main bodies 11, 21 in the z direction. As a result, the protrusion 12 has an inner surface 12a constituting an xy plane, and the end of the main body 11 in the x direction has an inner surface 11a constituting a yz plane. Similarly, the protrusion 22 has an inner surface 22a constituting an xy plane, and the end of the main body 21 in the x direction has an inner surface 21a constituting a yz plane.

[0021] 2 and 4, the sensor chip 100 and the external magnetic bodies 10 and 20 are positioned on the substrate 8 so that the side surface 101 of the sensor chip 100 is covered by the inner surface 11a of the external magnetic body 10 and the side surface 102 of the sensor chip 100 is covered by the inner surface 21a of the external magnetic body 20. That is, the positional relationship between the sensor chip 100 and the external magnetic body 10 in the x direction is fixed by abutting the side surface 101 of the sensor chip 100 against the inner surface 11a of the external magnetic body 10, and the positional relationship between the sensor chip 100 and the external magnetic body 20 in the x direction is fixed by abutting the side surface 102 of the sensor chip 100 against the inner surface 21a of the external magnetic body 20. This fixes the distance in the x direction of the magnetic gap G1 formed between the protrusion 12 and the protrusion 22. Furthermore, when the sensor chip 100 and the external magnetic bodies 10 and 20 are positioned in the x direction, the element formation surface 105 of the sensor chip 100 is covered with the inner surface 12a of the external magnetic body 10 and the inner surface 22a of the external magnetic body 20.

[0022] Furthermore, a groove 13 is formed at the corner where the inner surface 11a and the inner surface 12a of the external magnetic body 10 butt against each other. Similarly, a groove 23 is formed at the corner where the inner surface 12a and the inner surface 22a of the external magnetic body 20 butt against each other. This is because if the corner is rounded due to machining accuracy or the like, the rounded corner will interfere with the sensor chip 100 and the sensor chip 100 will not be positioned correctly. By removing the corner using the grooves 13 and 23, it becomes possible to position the sensor chip 100 correctly.

[0023] Furthermore, since the sensor chip 100 is mounted upright with the side surface 103 facing the substrate 8, if the sensor chip 100 is thin, there is a risk that the strength may be insufficient. In such a case, as shown in FIG. 5, the strength may be ensured by providing an auxiliary substrate 120 on the back surface 106 of the sensor chip 100. The auxiliary substrate 120 may be fixed to the sensor chip 100 and the substrate 8 using an adhesive or the like. The auxiliary substrate 120 may be made of the same material as the sensor chip 100.

[0024] FIG. 6 is a schematic perspective view for explaining the structure of the sensor chip 100. As shown in FIG.

[0025] 6, a magnetic sensing element R1, magnetic layers 111 and 112, and terminal electrodes T11 to T14 are formed on an element formation surface 105 of the sensor chip 100. The magnetic layers 111 and 112 are thin films made of a NiFe-based material such as permalloy, and the magnetic sensing element R1 is disposed on a magnetic path formed by a magnetic gap G2 made up of the magnetic layers 111 and 112.

[0026] FIG. 7 is a schematic perspective view showing the sensor chip 100 with the magnetic layers 111 and 112 removed.

[0027] As shown in FIG. 7, the magnetic sensing element R1 extends in the y direction on the element forming surface 105, one end of which is connected to the terminal electrode T11 via the wiring L1, and the other end of which is connected to the terminal electrode T12 via the wiring L2. The magnetic sensing element R1 is not particularly limited as long as it is an element whose electrical resistance changes depending on the direction of magnetic flux, and for example, an MR element can be used. The fixed magnetization direction, which is the sensitivity axis direction of the magnetic sensing element R1, is the x direction. The terminal electrodes T13 and T14 are connected to a compensation coil (not shown). The compensation coil is used to perform so-called closed loop control by canceling the magnetic field applied to the magnetic sensing element R1. In this embodiment, the sensor chip 100 is mounted upright so that the side surface 103 of the sensor chip 100 faces the substrate 8, and therefore the wiring distance between the terminal electrodes T11 to T14 and the substrate 8 can be shortened. This makes it possible to directly connect the land pattern provided on the substrate 8 to the terminal electrodes T11 to T14 using solder or the like.

[0028] FIG. 8 is an xz cross-sectional view of a main part of the sensor chip 100. As shown in FIG.

[0029] As shown in FIG. 8, a magnetic sensing element R1 is formed on the element formation surface 105 of the sensor chip 100. The magnetic sensing element R1 is covered with an insulating layer 107, and magnetic layers 111 and 112 are formed on the surface of the insulating layer 107. In addition, in a plan view (as viewed from the z direction), the magnetic sensing element R1 is located between the magnetic layers 111 and 112. As a result, a magnetic field passing through the magnetic gap G2 is applied to the magnetic sensing element R1. That is, the magnetic sensing element R1 is located near the magnetic gap G2 formed by the magnetic layers 111 and 112, and is disposed on a magnetic path capable of detecting a magnetic field to be detected passing through the magnetic gap G2. In this way, the magnetic sensing element R1 does not necessarily need to be disposed between the two magnetic layers 111 and 112, and it is sufficient that at least a part of the magnetic field passing through the magnetic gap G2 formed by the magnetic layers 111 and 112 is applied to the magnetic sensing element R1. There is no particular limitation on the relationship between the width of the magnetic gap G2 and the width of the magnetic sensing element R1. 8, the width G2x of the magnetic gap G2 in the x direction is narrower than the width Rx of the magnetic sensing element R1 in the x direction, and as a result, the magnetic layers 111, 112 and the magnetic sensing element R1 overlap when viewed from the z direction, creating an OV. In order to apply as much of the magnetic field passing through the magnetic gap G2 to the magnetic sensing element R1, it is desirable that the distance in the z direction between the magnetic layers 111, 112 and the magnetic sensing element R1 at the overlap OV is as close as possible, and it is more desirable that the distance in the z direction between the magnetic layers 111, 112 and the magnetic sensing element R1 is closer than the width G2x of the magnetic gap G2 in the x direction. As a result, the magnetic sensing element R1 becomes the main magnetic path of the magnetic field passing through the magnetic gap G2.

[0030] FIG. 9 is a schematic partial perspective view showing an enlarged view of a main part of the magnetic sensor 1. As shown in FIG.

[0031] As shown in FIG. 9, when the sensor chip 100 and the external magnetic bodies 10 and 20 are positioned in the x direction, the magnetic body layer 111 overlaps with the inner surface 12a of the external magnetic body 10, and the magnetic body layer 112 overlaps with the inner surface 22a of the external magnetic body 20. As a result, for example, the magnetic flux in the x direction collected by the main body part 11 of the external magnetic body 10 flows to the magnetic body layer 111 through the protruding part 12 of the external magnetic body 10. The magnetic flux flowing to the magnetic body layer 111 flows to the magnetic body layer 112 through the magnetic gap G2, and further flows to the main body part 21 through the protruding part 22 of the external magnetic body 20. When the magnetic flux in the x direction collected by the external magnetic bodies 10 and 20 flows through the magnetic gap G2, the magnetic flux in the x direction is applied to the magnetic sensing element R1, so that, for example, the direction and amount of the magnetic flux can be detected based on the change in the resistance value of the magnetic sensing element R1.

[0032] Here, it is preferable that the width G1x in the x direction of the magnetic gap G1 formed by the protrusions 12 and 22 is sufficiently wider than the width G2x in the x direction of the magnetic gap G2 formed by the magnetic layers 111 and 112. This is because if the width G1x of the magnetic gap G1 is too narrow, the magnetic flux bypasses the magnetic gap G1, and the magnetic flux applied to the magnetic sensing element R1 is reduced. As an example, the width G1x of the magnetic gap G1 may be about several hundred μm, and the width G2x of the magnetic gap G2 may be about several μm.

[0033] In this way, the magnetic sensor 1 according to this embodiment can apply the magnetic flux in the x direction collected by the external magnetic bodies 10 and 20 to the magnetic sensing element R1, whose sensitivity axis direction is in the x direction, without bending the magnetic flux, and therefore can obtain high detection sensitivity. Moreover, since the sensor chip 100 on which the magnetic sensing element R1 is formed and the external magnetic bodies 10 and 20 are positioned in the x direction, variation in the width G1x of the magnetic gap G1 is unlikely to occur, and thus variation in detection sensitivity can be reduced.

[0034] In addition, the inner surface 12a of the external magnetic body 10 and the inner surface 22a of the external magnetic body 20 have a shape in which the width in the y direction becomes narrower as they approach the magnetic gap G2, which makes it possible to further increase the magnetic flux density applied to the magnetic sensing element R1. However, it is not essential that the external magnetic bodies 10 and 20 have such a shape, and the width in the y direction of the inner surfaces 12a and 22a may be constant. This makes it easier to manufacture the external magnetic bodies 10 and 20.

[0035] FIG. 10 is a graph showing the relationship between the width of the magnetic gap G1 and the thickness of the protrusions 12 and 22 in the z direction and the magnetic flux density applied to the magnetic sensing element R1.

[0036] As shown in FIG. 10, in the region where the magnetic gap G1 is 0.6 mm or less, the narrower the magnetic gap G1, the higher the magnetic flux density applied to the magnetic sensing element R1. This is because the narrower the magnetic gap G1, the lower the magnetic resistance. On the other hand, when the magnetic gap G1 is less than 0.6 mm, the narrower the magnetic gap G1, the more rapidly the magnetic flux density applied to the magnetic sensing element R1 decreases. This is because if the magnetic gap G1 is too narrow, the magnetic flux bypasses between the external magnetic bodies 10 and 20, and the magnetic flux applied to the magnetic sensing element R1 decreases. In addition, the thinner the thickness of the protrusions 12 and 22 in the z direction, the higher the magnetic flux density applied to the magnetic sensing element R1. This is because the thinner the thickness of the protrusions 12 and 22 in the z direction, the more difficult it is for the magnetic flux to bypass between the external magnetic bodies 10 and 20.

[0037] As shown in Fig. 11(a), by connecting the magnetic sensing element R1 and the fixed resistor R10 in series between the power supply, a detection signal V1 can be obtained from the connection point between the two. The fixed resistor R10 may be provided on the element forming surface 105 of the sensor chip 100, or on the substrate 8. When the fixed resistor R10 is provided on the element forming surface 105 of the sensor chip 100, a dummy element having the same configuration as the magnetic sensing element R1 and whose resistance value does not change due to a magnetic field may be used as the fixed resistor R10. Also, as shown in Fig. 11(b), the magnetic sensing element R1 and the fixed resistors R11 to R13 may be bridge-connected to obtain the detection signals V2 and V3.

[0038] Fig. 12 is a schematic perspective view showing the appearance of a magnetic sensor 2 according to a second embodiment of the present invention, and Figs. 13 and 14 are schematic exploded perspective views of parts of the magnetic sensor 2.

[0039] 12 to 14, the magnetic sensor 2 according to the second embodiment differs from the magnetic sensor 1 according to the first embodiment in that it further includes a sensor chip 200 and external magnetic bodies 30, 40 mounted on a substrate 8. Since the other basic configurations are the same as those of the magnetic sensor 1 according to the first embodiment, the same elements are given the same reference numerals and redundant explanations will be omitted.

[0040] The sensor chip 200 has the same structure as the sensor chip 100, and has side surfaces 201 and 202 which form a yz plane and are located opposite each other, side surfaces 203 and 204 which form an xz plane and are located opposite each other, and an element forming surface 205 and a back surface 206 which form an xy plane and are located opposite each other. The sensor chip 200 is mounted on the substrate 8 such that the side surface 203 faces the main surface of the substrate 8.

[0041] The external magnetic bodies 30 and 40 are both made of a high magnetic permeability material such as ferrite, and have the same structure as the external magnetic bodies 20 and 10. The external magnetic body 30 is composed of a rod-shaped main body 31 whose longitudinal direction is the x direction, and a protruding portion 32 provided at the end of the main body 31 in the x direction. Similarly, the external magnetic body 40 is composed of a rod-shaped main body 41 whose longitudinal direction is the x direction, and a protruding portion 42 provided at the end of the main body 41 in the x direction. The external magnetic bodies 10 and 40 are arranged in the z direction, and the external magnetic bodies 20 and 30 are arranged in the z direction. In this embodiment, the thickness of the main body 11 and 41 of the external magnetic bodies 10 and 40 in the z direction is thicker than the thickness of the main body 21 and 31 of the external magnetic bodies 20 and 30 in the z direction. The main body parts 11, 41 of the external magnetic bodies 10, 40 are in contact with each other, whereas the main body parts 21, 31 of the external magnetic bodies 20, 30 are spaced apart from each other in the z direction. The external magnetic bodies 10, 40 may be made of a single block. With this configuration, the tip part in the +x direction of the external magnetic bodies 10, 40 can be used as a detection head to collect magnetic flux in the x direction.

[0042] 13 and 14, the sensor chip 200 and the external magnetic bodies 30, 40 are positioned on the substrate 8 so that the side surface 201 of the sensor chip 200 is covered by the inner surface 31a of the external magnetic body 30, and the side surface 202 of the sensor chip 200 is covered by the inner surface 41a of the external magnetic body 40. That is, the positional relationship between the sensor chip 200 and the external magnetic body 30 in the x direction is fixed by abutting the side surface 201 of the sensor chip 200 against the inner surface 31a of the external magnetic body 30, and the positional relationship between the sensor chip 200 and the external magnetic body 40 in the x direction is fixed by abutting the side surface 202 of the sensor chip 200 against the inner surface 41a of the external magnetic body 40. This fixes the distance in the x direction of the magnetic gap formed between the protrusion 32 and the protrusion 42. Furthermore, when the sensor chip 200 and the external magnetic bodies 30 and 40 are positioned in the x direction, the element formation surface 205 of the sensor chip 200 is covered with the inner surface 32a of the external magnetic body 30 and the inner surface 42a of the external magnetic body 40.

[0043] The magnetic sensing element R2 and magnetic layers 211 and 212 are formed on the element formation surface 205 of the sensor chip 200. The magnetic layers 211 and 212 are thin films made of a NiFe-based material such as permalloy, and the magnetic sensing element R2 is disposed on a magnetic path formed by a magnetic gap made of the magnetic layers 211 and 212. When the sensor chip 200 and the external magnetic bodies 30 and 40 are positioned in the x direction, the magnetic layer 211 overlaps the inner surface 32a of the external magnetic body 30, and the magnetic layer 212 overlaps the inner surface 42a of the external magnetic body 40.

[0044] The sensor chip 100 and the sensor chip 200 are arranged so that the rear surfaces 106 and 206 face each other. As a result, the sensitivity axis directions of the magnetic sensing element R1 and the magnetic sensing element R2 are different from each other by 180°. For example, if the sensitivity axis direction of the magnetic sensing element R1 is the +x direction, the sensitivity axis direction of the magnetic sensing element R2 is the -x direction. Therefore, as shown in FIG. 15(a), by connecting the magnetic sensing element R1 and the magnetic sensing element R2 in series between the power source, a detection signal V4 with a larger amplitude can be obtained from the connection point between the two. Also, as shown in FIG. 15(b), the magnetic sensing elements R1 and R2 and the fixed resistors R14 and R15 may be bridge-connected to obtain differential signals V5 and V6. Furthermore, the magnetic sensing elements R1 and R2 may be bridge-connected to form a double full bridge.

[0045] 16, a spacer 300 may be provided between the sensor chip 100 and the sensor chip 200 in contact with the rear surfaces 106, 206. This reduces the temperature difference between the sensor chip 100 and the sensor chip 200 due to heat conduction through the spacer 300, making it possible to reduce measurement errors caused by the temperature difference. Moreover, since the rear surfaces 106, 206 of the sensor chips 100, 200 are covered with the spacer 300, the overall mechanical strength is also increased.

[0046] Fig. 17 is a schematic perspective view showing the appearance of a magnetic sensor 3 according to the third embodiment of the present invention, and Fig. 18 is a schematic exploded perspective view of a part of the magnetic sensor 3.

[0047] 17 and 18, the magnetic sensor 3 according to the third embodiment differs from the magnetic sensor 2 according to the second embodiment in that the back surface 106 of the sensor chip 100 and the back surface 206 of the sensor chip 200 are in contact with each other, and the main bodies 21, 31 of the external magnetic bodies 20, 30 are in contact with each other. As the other basic configurations are the same as those of the magnetic sensor 2 according to the second embodiment, the same elements are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0048] As in the magnetic sensor 3 according to the third embodiment, by bringing the rear surfaces 106, 206 of the sensor chips 100, 200 into contact with each other, the temperature difference between the sensor chips 100 and 200 becomes smaller, so that it becomes possible to further reduce measurement errors caused by the temperature difference. In this embodiment as well, the external magnetic bodies 10, 40 may be formed of a single block, and the external magnetic bodies 20, 30 may be formed of a single block.

[0049] Although a preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present invention, and it goes without saying that these modifications are also included within the scope of the present invention. [Explanation of symbols]

[0050] 1~3 Magnetic sensors 8 Substrate 10,20,30,40 External magnetic body 11, 21, 31, 41 Main body 12,22,32,42 Protrusion 11a, 12a, 21a, 22a, 31a, 32a, 41a, 42a Inner surface 13,23 groove 100,200 sensor chips 101~104,201~204 Side 105,205 Element formation surface 106,206 back side 107 Insulating layer 111,112,211,212 Magnetic layer 120 Auxiliary Board 300 Spacer G1, G2 magnetic gap L1, L2 wiring R1, R2 magnetic sensing element R10~R15 Fixed resistance T11~T14 Terminal electrode

Claims

1. a first sensor chip having an element forming surface extending in a first direction and a second direction perpendicular to the first direction, and first and second side surfaces perpendicular to the first direction and parallel to each other; a first external magnetic body and a second external magnetic body, the first direction being a longitudinal direction of the first external magnetic body; On the element forming surface, first and second magnetic layers arranged in the first direction with a first magnetic gap interposed therebetween, and a first magnetic sensing element disposed on a magnetic path formed by the first magnetic gap and having a magnetic sensing direction in the first direction are formed; the first external magnetic body has a first inner surface covering the element forming surface so as to overlap the first magnetic layer, and a second inner surface covering the first side surface; A magnetic sensor characterized in that the second external magnetic body has a third inner surface covering the element forming surface so as to overlap the second magnetic layer, and a fourth inner surface covering the second side surface.

2. 2. The magnetic sensor according to claim 1, wherein the first inner surface of the first external magnetic body and the third inner surface of the second external magnetic body have a shape whose width in the second direction narrows as they approach the first magnetic gap.

3. the first external magnetic body has a structure in which a corner portion where the first inner surface and the second inner surface meet is removed, 3. The magnetic sensor according to claim 1, wherein the second external magnetic body has a structure in which a corner where the third inner surface and the fourth inner surface butt against each other is removed.

4. a substrate on which the first sensor chip, the first external magnetic body, and the second external magnetic body are mounted, 4. The magnetic sensor according to claim 1, wherein the first sensor chip is mounted such that a third side surface perpendicular to the second direction faces the substrate.

5. 5. The magnetic sensor according to claim 4, further comprising an auxiliary substrate mounted on the substrate and disposed on a back surface of the first sensor chip opposite to the element formation surface.

6. a second sensor chip having an element forming surface extending in the first and second directions and fourth and fifth side surfaces perpendicular to the first direction and parallel to each other; and third and fourth external magnetic bodies having a longitudinal direction in the first direction, On the element forming surface of the second sensor chip, third and fourth magnetic layers arranged in the first direction via a second magnetic gap, and a second magnetic sensing element arranged on a magnetic path formed by the second magnetic gap and having a magnetic sensing direction in the first direction are formed; the third external magnetic body has a fifth inner surface covering the element forming surface so as to overlap the third magnetic layer, and a sixth inner surface covering the fourth side surface; the fourth external magnetic body has a seventh inner surface covering the element forming surface so as to overlap the fourth magnetic layer, and an eighth inner surface covering the fifth side surface, 5. The magnetic sensor according to claim 1, wherein the sensitivity axes of the first magnetic sensitive element and the second magnetic sensitive element are different from each other by 180 degrees.

7. 7. The magnetic sensor according to claim 6, wherein the first sensor chip and the second sensor chip are arranged such that their back surfaces, which are located opposite the element formation surface, face each other.

8. The magnetic sensor according to claim 7 , further comprising a spacer in contact with the rear surface of the first sensor chip and the rear surface of the second sensor chip.

9. 8. The magnetic sensor according to claim 7, wherein the rear surface of the first sensor chip and the rear surface of the second sensor chip are in contact with each other.

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