JP6927044B2 - Magnetic sensor - Google Patents

Description

The present invention relates to a magnetic sensor, and more particularly to a magnetic sensor provided with a magnetic material for collecting magnetic flux in a sensor chip.

Magnetic sensors using giant magnetoresistive elements and the like are widely used in ammeters, magnetic encoders, and the like. The magnetic sensor may be provided with a magnetic material for collecting magnetic flux on the sensor chip. In this case, the magnetic material is placed on the element forming surface of the sensor chip (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2009-276159

However, since the sensor chip is generally small, it is not easy to place the magnetic material on the sensor chip, and it is difficult to securely fix the sensor chip and the magnetic material. Further, when the magnetic material is placed on the element forming surface of the sensor chip, the height of the entire magnetic sensor becomes high, so that it is difficult to reduce the height.

Therefore, an object of the present invention is to provide a magnetic sensor capable of more reliably fixing the sensor chip and the magnetic material and achieving a low profile.

The magnetic sensor according to the present invention includes a sensor chip having an element forming surface on which at least one magnetic detection element is formed and a side surface substantially perpendicular to the element forming surface, and a first side surface of the sensor chip. It is characterized by having a magnetic material of.

According to the present invention, since the first magnetic material is provided on the side surface of the sensor chip, the contact area between the sensor chip and the magnetic material can be expanded. Therefore, both can be fixed more reliably. Moreover, it is possible to realize a low profile.

It is preferable that the magnetic sensor according to the present invention further includes a second magnetic material which is the element forming surface of the sensor chip and is provided in the vicinity of the side surface. According to this, the magnetic flux in the direction perpendicular to the element forming surface can be further bent in the horizontal direction, so that the detection sensitivity can be improved.

In the present invention, the magnetic detection element includes the first and second magnetic detection elements, and it is preferable that the first and second magnetic detection elements have different distances from the side surface. According to this, it becomes possible to perform magnetic detection by utilizing the output difference between the first magnetic detection element and the second magnetic detection element.

In this case, the magnetic detection element includes a third magnetic detection element whose distance from the side surface is equal to that of the first magnetic detection element, and a fourth magnetic detection element whose distance from the side surface is equal to that of the second magnetic detection element. It is preferable to further include a magnetic detection element. According to this, it is possible to form a differential bridge circuit using the first to fourth magnetic detection elements, and in this case, it is possible to perform magnetic detection with higher sensitivity.

The magnetic sensor according to the present invention preferably further includes a circuit board having a mounting surface on which the sensor chip is mounted. In this case, the element forming surface of the sensor chip may be substantially parallel to the mounting surface of the circuit board, or may be substantially perpendicular to the mounting surface of the circuit board.

According to the present invention, the sensor chip and the magnetic material can be fixed more reliably, and the height of the magnetic sensor can be reduced.

FIG. 1 is a schematic perspective view showing the appearance of the magnetic sensor 10A according to the preferred first embodiment of the present invention. FIG. 2 is a circuit diagram of a magnetic field detection device using the magnetic sensor 10A. FIG. 3 is a schematic perspective view showing the appearance of the magnetic sensor 10B according to the preferred second embodiment of the present invention. FIG. 4 is a diagram showing an example in which the first magnetic body 41 and the second magnetic body 42 are integrated. FIG. 5 is a schematic perspective view showing the appearance of the magnetic sensor 10C according to the preferred third embodiment of the present invention. FIG. 6 is a schematic perspective view showing the appearance of the magnetic sensor 10D according to the preferred fourth embodiment of the present invention. FIG. 7 is a schematic perspective view showing the appearance of the magnetic sensor 10E according to the preferred fifth embodiment of the present invention. FIG. 8 is a circuit diagram of a magnetic field detection device using the magnetic sensor 10E. FIG. 9 is a schematic perspective view showing the appearance of the magnetic sensor 10F according to the preferred sixth embodiment of the present invention. FIG. 10 is a schematic perspective view showing the appearance of the magnetic sensor 10G according to the preferred seventh embodiment of the present invention. FIG. 11 is a schematic perspective view showing the appearance of the magnetic sensor 10H according to the preferred eighth embodiment of the present invention. FIG. 12 is a schematic perspective view showing the appearance of the magnetic sensor 10I according to the preferred ninth embodiment of the present invention. FIG. 13 is a circuit diagram of a magnetic field detection device using the magnetic sensor 10I. FIG. 14 is a schematic perspective view showing the appearance of the magnetic sensor 10J according to the preferred tenth embodiment of the present invention. FIG. 15 is a schematic perspective view showing the appearance of the magnetic sensor 10K according to the preferred eleventh embodiment of the present invention. FIG. 16 is a schematic perspective view showing the appearance of the magnetic sensor 10L according to the preferred twelfth embodiment of the present invention.

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

FIG. 1 is a schematic perspective view showing the appearance of the magnetic sensor 10A according to the preferred first embodiment of the present invention.

As shown in FIG. 1, the magnetic sensor 10A according to the present invention is composed of a circuit board 20, a sensor chip 30 mounted on a mounting surface 21 of the circuit board 20, and a first magnetic body 41.

The circuit board 20 is a board in which a wiring pattern is formed on an insulating substrate such as resin, and a general printed circuit board, an interposer board, or the like can be used. The mounting surface 21 of the circuit board 20 forms an xy plane, and the sensor chip 30 and the first magnetic body 41 are mounted on the mounting surface 21. A land pattern for establishing an electrical connection with the sensor chip 30 is provided on the mounting surface 21 of the circuit board 20, but it is not shown in FIG. A constant voltage source 51, an operational amplifier 52, a fixed resistor 53, a voltage detection circuit 54, and the like shown in FIG. 2 are connected to the land pattern. The constant voltage source 51, the operational amplifier 52, the fixed resistor 53, and the voltage detection circuit 54 may be provided on the circuit board 20 itself, or may be provided on a board different from the circuit board 20.

The sensor chip 30 has a substantially rectangular parallelepiped shape, and a magnetic detection element MR is formed on the element forming surface 31. As shown in FIG. 1, the element forming surface 31 constitutes an xy surface. That is, the sensor chip 30 is mounted flat so that the element forming surface 31 is substantially parallel to the mounting surface 21 of the circuit board 20.

The magnetic detection element MR is not particularly limited as long as it is an element whose physical characteristics change depending on the magnetic flux density, but in the present embodiment, a magnetoresistive effect element whose resistance value changes according to the direction of the input magnetic field is used. .. The magnetization fixing direction of the magnetic detector MR is set to the direction indicated by the arrow A in FIG. 1 (minus side in the x direction). A large number of sensor chips 30 are simultaneously manufactured using an assembly substrate, and a large number of sensor chips 30 are taken by dicing them. Therefore, the four side surfaces 32 formed by dicing are substantially perpendicular to the element forming surface 31.

The first magnetic body 41 is a block made of a high magnetic permeability material such as ferrite, and has a substantially rectangular parallelepiped shape in the present embodiment. Then, in the present embodiment, the first magnetic body 41 is provided not on the element forming surface 31 of the sensor chip 30 but on one side surface 32. More specifically, the yz plane of the sensor chip 30 and the yz plane of the first magnetic body 41 are fixed to each other so as to face each other. Here, the length of the sensor chip 30 in the y direction and the length of the first magnetic body 41 in the y direction may be the same or different from each other. Further, the height of the sensor chip 30 in the z direction and the height of the first magnetic body 41 in the z direction may be the same or different from each other. However, the height of the first magnetic body 41 in the z direction is preferably equal to or less than the height of the sensor chip 30 in the z direction.

The sensor chip 30 and the first magnetic body 41 can be fixed by using an adhesive. In this case, since the magnetic detection element MR is not provided on the side surface 32 of the sensor chip 30, the first magnetic body 41 can be fixed so as to cover almost the entire surface of the side surface 32, thereby fixing both. Can be done more reliably. Further, if an adhesive is also applied between the circuit board 20 and the first magnetic body 41, the first magnetic body 41 is fixed to both the circuit board 20 and the sensor chip 30, so that the first magnetic body 41 can be fixed. The magnetic body 41 is more firmly fixed.

As described above, in the magnetic sensor 10A according to the present embodiment, the sensor chip 30 is horizontally placed on the circuit board 20, and the first magnetic body 41 is provided on the side surface 32 of the sensor chip 30. As a result, a sufficient bonding area between the sensor chip 30 and the first magnetic body 41 can be secured, so that the sensor chip 30 and the first magnetic body 41 can be more reliably fixed. Moreover, the height in the z direction can be made lower than that of the conventional magnetic sensor.

FIG. 2 is a circuit diagram of a magnetic field detection device using the magnetic sensor 10A.

The magnetic field detection device shown in FIG. 2 includes a constant voltage source 51, an operational amplifier 52, a fixed resistor 53, and a voltage detection circuit 54 connected to the magnetic sensor 10A. As shown in FIG. 2, the magnetic detector MR and the fixed resistor 53 included in the magnetic sensor 10A are connected in series between the output terminal of the operational amplifier 52 and the ground, and the connection point is the inversion of the operational amplifier 52. It is connected to the input terminal (-). A predetermined input voltage is applied to the non-inverting input terminal (+) of the operational amplifier 52 by the constant voltage source 51.

With this configuration, the constant voltage source 51, the operational amplifier 52, and the fixed resistor 53 function as constant current sources. Therefore, when the resistance value of the magnetic detector MR changes, the voltage between both ends of the magnetic detector MR changes. This change is detected by the voltage detection circuit 54. As a result, the magnetic field detection device shown in FIG. 2 can detect the magnetic field applied to the magnetic detection element MR. Then, in the present embodiment, the detection sensitivity is enhanced because the magnetism is collected by the first magnetic body 41 provided on the side surface 32 of the sensor chip 30.

FIG. 3 is a schematic perspective view showing the appearance of the magnetic sensor 10B according to the preferred second embodiment of the present invention.

The magnetic sensor 10B shown in FIG. 3 differs from the magnetic sensor 10A shown in FIG. 1 in that a second magnetic body 42 is further provided on the element forming surface 31 of the sensor chip 30. Since the other points are the same as those of the magnetic sensor 10A shown in FIG. 1, the same elements are designated by the same reference numerals, and duplicate description will be omitted.

The second magnetic body 42 is a rod-shaped body whose longitudinal direction is the y direction, is an element forming surface 31 of the sensor chip 30, and is provided in the vicinity of the side surface 32 where the first magnetic body 41 is provided. .. The first magnetic body 41 and the second magnetic body 42 do not need to be in contact with each other, but it is preferable that they are as close as possible to each other. The second magnetic material 42 may be made of the same material as the first magnetic material 41, or may be made of a different material. Since the second magnetic material is smaller in size than the first magnetic material 41, instead of adhering a member (for example, a ferrite block) made of the same material as the first magnetic material 41, a thick film process or a thin film is used. It may be formed directly on the element forming surface 31 of the sensor chip 30 by using the process. Further, the first magnetic body 41 and the second magnetic body do not have to be separate members, and both may be integrated as shown in FIG.

With this configuration, the magnetic sensor 10B according to the present embodiment can bend the magnetic flux in the z direction collected by the first magnetic body 41 in the x direction by the second magnetic body 42. As a result, the magnetic flux component in the sensitivity direction (x direction) of the magnetic detection element MR increases, so that it is possible to obtain a detection sensitivity higher than that of the magnetic sensor 10A according to the first embodiment.

FIG. 5 is a schematic perspective view showing the appearance of the magnetic sensor 10C according to the preferred third embodiment of the present invention.

The magnetic sensor 10C shown in FIG. 5 differs from the magnetic sensor 10A shown in FIG. 1 in that the sensor chip 30 and the first magnetic body 41 are mounted on the circuit board 20 in a state of being rotated by 90 °. Since the other points are the same as those of the magnetic sensor 10A shown in FIG. 1, the same elements are designated by the same reference numerals, and duplicate description will be omitted.

In the present embodiment, since the sensor chip 30 and the first magnetic body 41 are rotated by 90 °, the element forming surface 31 of the sensor chip 30 forms the yz surface, and the magnetization fixing direction of the magnetic detection element MR (arrow). A) is set to the minus side in the z direction. As described above, in the present embodiment, the diced sensor chip 30 is mounted on the circuit board 20 in a state of being laid on the side by 90 °.

The first magnetic body 41 is provided on the xy surface, which is the side surface 32 of the sensor chip 30. In the example shown in FIG. 5, the first magnetic body 41 is provided on the upper side of the sensor chip 30, but the first magnetic body is provided on the lower side of the sensor chip 30, that is, between the circuit board 20 and the sensor chip 30. The body 41 may be arranged.

The magnetic sensor 10C according to the present embodiment can achieve the same low profile as the magnetic sensor 10A according to the first embodiment by lowering the height in the z direction by dicing the sensor chip 30 smaller. It becomes.

FIG. 6 is a schematic perspective view showing the appearance of the magnetic sensor 10D according to the preferred fourth embodiment of the present invention.

The magnetic sensor 10D shown in FIG. 6 is different from the magnetic sensor 10C shown in FIG. 5 in that a second magnetic body 42 is further provided on the element forming surface 31 of the sensor chip 30. Since the other points are the same as those of the magnetic sensor 10C shown in FIG. 5, the same elements are designated by the same reference numerals, and duplicate description will be omitted.

In the magnetic sensor 10D according to the present embodiment, the magnetic flux in the x direction collected by the first magnetic body 41 can be further bent in the z direction by the second magnetic body 42. As a result, the magnetic flux component in the sensitivity direction (z direction) of the magnetic detection element MR increases, so that it is possible to obtain a detection sensitivity higher than that of the magnetic sensor 10C according to the third embodiment.

FIG. 7 is a schematic perspective view showing the appearance of the magnetic sensor 10E according to the preferred fifth embodiment of the present invention.

The magnetic sensor 10E shown in FIG. 7 differs from the magnetic sensor 10A shown in FIG. 1 in that two magnetic detection elements MR1 and MR2 are provided on the element forming surface 31 of the sensor chip 30. Since the other points are the same as those of the magnetic sensor 10A shown in FIG. 1, the same elements are designated by the same reference numerals, and duplicate description will be omitted.

As shown in FIG. 7, the magnetic detectors MR1 and MR2 are arranged side by side in the x direction, and the magnetization fixing direction is aligned in the direction indicated by the arrow A (minus side in the x direction). The magnetic detector MR1 is arranged closer to the first magnetic body 41, and the magnetic detector MR2 is arranged farther from the first magnetic body 41.

With this configuration, the amount of change in resistance of the magnetic detectors MR1 and MR2 is almost the same for the magnetic flux in the x direction, but the distance from the first magnetic body 41 is different for the magnetic flux in the z direction. There is a difference in the amount of resistance change between the magnetic detectors MR1 and MR2. Therefore, by detecting this difference, it is possible to selectively detect the magnetic flux in the z direction.

FIG. 8 is a circuit diagram of a magnetic field detection device using the magnetic sensor 10E.

The magnetic field detector shown in FIG. 8 differs from the magnetic field detector shown in FIG. 2 in that the fixed resistor 53 shown in FIG. 2 is replaced with the magnetic detector MR2. Then, in the magnetic field detection device shown in FIG. 8, the magnetic detection element MR2 can be used as a fixed resistor having almost no sensitivity to the magnetic flux in the z direction. As a result, the constant voltage source 51, the operational amplifier 52, and the magnetic detector MR2 function as a constant current source. Therefore, when the resistance value of the magnetic detector MR1 changes, the voltage between both ends of the magnetic detector MR1 changes. This change is detected by the voltage detection circuit 54. As a result, the magnetic field detection device shown in FIG. 8 can detect the magnetic field applied to the magnetic detection element MR1. Further, since the magnetic detection element MR2 functions as a fixed resistor, it is not necessary to separately provide a fixed resistor in the magnetic field detection device.

9 to 11 are schematic perspective views showing the appearance of the magnetic sensors 10F to 10H according to the preferred sixth to eighth embodiments of the present invention, respectively.

The magnetic sensor 10F according to the sixth embodiment shown in FIG. 9 is a magnetic sensor 10E to which a second magnetic body 42 is added, and its significance is as described with reference to FIG. Further, the magnetic sensor 10G according to the seventh embodiment shown in FIG. 10 is obtained by rotating the sensor chip 30 of the magnetic sensor 10E and the first magnetic body 41 by 90 °, and its significance is referred to with reference to FIG. As explained. Further, in the magnetic sensor 10H according to the eighth embodiment shown in FIG. 11, a second magnetic body 42 is added to the magnetic sensor 10E, and the sensor chip 30 and the first magnetic body 41 are rotated by 90 °. The significance of this is as explained with reference to FIG.

FIG. 12 is a schematic perspective view showing the appearance of the magnetic sensor 10I according to the preferred ninth embodiment of the present invention.

The magnetic sensor 10I shown in FIG. 12 differs from the magnetic sensor 10E shown in FIG. 7 in that four magnetic detection elements MR1 to MR4 are provided on the element forming surface 31 of the sensor chip 30. Since the other points are the same as those of the magnetic sensor 10E shown in FIG. 7, the same elements are designated by the same reference numerals, and duplicate description will be omitted.

As shown in FIG. 12, the magnetic detection elements MR1 to MR4 are all aligned in the direction indicated by the arrow A (minus side in the x direction). Further, the magnetic detection element MR1 and the magnetic detection element MR2 are arranged side by side in the x direction, and the magnetic detection element MR3 and the magnetic detection element MR4 are arranged side by side in the x direction. The magnetic detectors MR1 and MR3 are arranged close to the first magnetic body 41, and the magnetic detectors MR2 and MR4 are arranged far from the first magnetic body 41. Here, the distances from the first magnetic body 41 are equal to each other in the magnetic detection elements MR1 and MR3, and equal to each other in the magnetic detection elements MR2 and MR4.

With this configuration, the amount of change in resistance of the magnetic detectors MR1 to MR4 is almost the same for the magnetic flux in the x direction, but the distance from the first magnetic body 41 is different for the magnetic flux in the z direction. There is a difference in the amount of change in resistance of the magnetic detectors MR1 and MR2, and a difference in the amount of change in resistance of the magnetic detectors MR3 and MR4. And the difference is equal to each other. Therefore, by detecting these differences, it is possible to selectively detect the magnetic flux in the z direction.

FIG. 13 is a circuit diagram of a magnetic field detection device using the magnetic sensor 10I.

In the magnetic field detection device shown in FIG. 13, four magnetic detection elements MR1 to MR4 form a bridge circuit. That is, the magnetic detector MR1 is connected between the terminals E1 and E3, the magnetic detector MR2 is connected between the terminals E2 and E3, the magnetic detector MR3 is connected between the terminals E2 and E4, and the magnetic detector MR4 is a terminal. It is connected between E1 and E4. Then, a predetermined voltage is applied between the terminals E1 and E2 by the constant voltage source 51. Further, a voltage detection circuit 54 is connected between the terminals E3 and E4, whereby the level of the output voltage appearing between the terminals E3 and E4 is detected.

Then, as shown in FIG. 13, since the connection order of the magnetic detection elements MR1 and MR2 and the connection order of the magnetic detection elements MR3 and MR4 are reversed from each other, the magnetic detection elements MR1 to MR4 are differential bridge circuits. To configure. As a result, the change in the electrical resistance of the magnetic detectors MR1 to MR4 according to the magnetic flux density is amplified twice, so that more sensitive detection can be performed.

14 to 16 are schematic perspective views showing the appearance of the magnetic sensors 10J to 10L according to the preferred embodiments of the present invention, respectively.

The magnetic sensor 10J according to the tenth embodiment shown in FIG. 14 is a magnetic sensor 10I to which a second magnetic body 42 is added, and its significance is as described with reference to FIG. Further, the magnetic sensor 10K according to the eleventh embodiment shown in FIG. 15 is obtained by rotating the sensor chip 30 of the magnetic sensor 10I and the first magnetic body 41 by 90 °, and its significance is referred to with reference to FIG. As explained. Further, in the magnetic sensor 10L according to the twelfth embodiment shown in FIG. 16, a second magnetic body 42 is added to the magnetic sensor 10I, and the sensor chip 30 and the first magnetic body 41 are rotated by 90 °. The significance of this is as explained with reference to FIG.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the present invention, and these are also the present invention. Needless to say, it is included in the range.

10A-10L Magnetic sensor 20 Circuit board 21 Mounting surface 30 Sensor chip 31 Element forming surface 32 Side surface 41 First magnetic body 42 Second magnetic body 51 Constant voltage source 52 Operational amplifier 53 Fixed resistance 54 Voltage detection circuit E1 to E4 terminal MR , MR1-MR4 Magnetic detector

Claims (5)

With the circuit board
A sensor chip mounted on the mounting surface of the circuit board and having an element forming surface on which at least one magnetic detection element is formed and four side surfaces substantially perpendicular to the element forming surface.
A first magnetic body provided in the four first side which is one side of the sensor chip,
It is provided with a second magnetic material which is the element forming surface of the sensor chip and is provided in the vicinity of the first side surface.
The second magnetic material is arranged so as not to overlap with the magnetic detection element .
Of the four side surfaces of the sensor chip, the second side surface located on the opposite side of the first side surface is not provided with a magnetic material.
The magnetic detector includes first and second magnetic detectors.
The first and second magnetic detection elements are magnetic sensors characterized in that the distances from the first side surface are different from each other. The magnetic sensor according to claim 1, wherein the first and second magnetic materials are made of a block in which both are integrated. The magnetic detecting element, and the equal to the first distance from the side of said first magnetic detecting element 3 of the magnetic sensor, the distance from the first side surface is equal to the second magnetic detection element The magnetic sensor according to claim 1 or 2 , further comprising a fourth magnetic detector element. The element formation surface of the front Symbol sensor chip, a magnetic sensor according to any one of claims 1 to 3, wherein the mounting surface of the circuit board to be substantially parallel. The element formation surface of the front Symbol sensor chip, a magnetic sensor according to any one of claims 1 to 3, characterized in that it is substantially perpendicular to the mounting surface of the circuit board.

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