JP2013011528A - Rotation detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotation detector that suppresses decrease in detection sensitivity of a rotational state.SOLUTION: A rotation detector that comprises a sensor chip (10) having a plurality of magnetoelectric transducers (13, 14) and a cylindrical magnet (30) provided with the sensor chip (10) in a hollow thereof detects a rotational state of an object to be detected by detecting changes in a magnetic field, formed by the cylindrical magnet (30), caused by a rotation of the object to be detected, with the magnetoelectric transducers (13, 14). The sensor chip (10) includes a semiconductor substrate (11) formed with the magnetoelectric transducer (13) and a semiconductor substrate (12) formed with the magnetoelectric transducer (14), and the two semiconductor substrates (11, 12) are connected via a joint member (15).

Description

  The present invention relates to a rotation detection device having a sensor chip having a plurality of magnetoelectric conversion elements and a cylindrical magnet provided with a sensor chip in a hollow space.

  Conventionally, as shown in Patent Document 1, for example, a rotation detection device including a sensor chip having a magnetic detection element and a magnet that applies a magnetic field to the magnetic detection element of the sensor chip has been proposed. In this rotation detection device, the rotation state of the magnetic body is detected by sensing the change of the magnetic field due to the rotation of the magnetic body by the magnetic detection element.

JP 2007-232372 A

  By the way, the magnet of the rotation detector shown in Patent Document 1 is a cylindrical magnet, and a sensor chip is disposed in the hollow of the cylindrical magnet. The sensor chip is a single chip in which a magnetoresistive element and its processing circuit are integrated. Usually, the magnetoresistive elements are arranged side by side in the rotation direction of the magnetic material or in the tangential direction thereof in order to detect a change in the magnetic field due to the rotation of the magnetic material. Therefore, the lateral width of the sensor chip and the inner diameter of the cylindrical magnet that houses the sensor chip are determined by the number of magnetoresistive elements.

  As described above, in the rotation detection device disclosed in Patent Document 1, magnetoresistive elements are integrated on one sensor chip. Therefore, there is a possibility that the lateral width of the sensor chip and the inner diameter of the cylindrical magnet become long. The density of the magnetic field formed by the cylindrical magnet decreases as the distance from the cylindrical magnet increases. Therefore, when the inner diameter of the cylindrical magnet becomes longer, the axial magnetic field passing through the center of the cylindrical magnet becomes thinner. As a result, a change in the magnetic field due to the rotation of the magnetic body is reduced, and there is a possibility that the detection sensitivity of the rotation state is lowered.

  In view of the above problems, an object of the present invention is to provide a rotation detection device in which a decrease in detection sensitivity of a rotation state is suppressed.

  In order to achieve the above-described object, the invention according to claim 1 includes a sensor chip (10) having a plurality of magnetoelectric transducers (13, 14) and a cylinder in which the sensor chip (10) is provided in a hollow space. And detecting the change of the magnetic field formed by the cylindrical magnet (30) due to the rotation of the detected object by the magnetoelectric conversion element (13, 14), thereby rotating the detected object. The sensor chip (10) includes a semiconductor substrate (11) on which the magnetoelectric conversion element (13) is formed, and a semiconductor substrate (12) on which the magnetoelectric conversion element (14) is formed. The two semiconductor substrates (11, 12) are bonded via the bonding member (15).

  Thus, according to the present invention, the sensor chip (10) is formed by forming the magnetoelectric conversion elements (13, 14) on the two bonded semiconductor substrates (11, 12). Therefore, the lateral width of the sensor chip (10) and the inner diameter of the cylindrical magnet (30) can be shortened compared to a sensor chip in which a magnetoelectric conversion element is formed on one semiconductor substrate. As a result, the axial magnetic field penetrating through the center of the cylindrical magnet (30) is suppressed from being reduced, and a decrease in detection sensitivity in the rotational state is suppressed.

  As described in claim 2, the joining member (15) has an annular shape, and is constituted by the joining member (15) and opposing surfaces (11a, 12a) of the two semiconductor substrates (11, 12). A configuration in which the magnetoelectric conversion elements (13, 14) are arranged in a sealed space is preferable.

  According to this, since the magnetoelectric conversion elements (13, 14) are protected in the sealed space, contamination by foreign matter or the like is suppressed. Moreover, since it isolate | separates from external atmosphere, the change of the characteristic of the magnetoelectric conversion element (13, 14) by the change of external temperature is suppressed. As a result, a decrease in the detection sensitivity of the rotation state is suppressed.

  A structure in which the joining member (15) and the semiconductor substrate (11, 12) are directly joined is preferable. According to this, since two semiconductor substrates (11, 12) can be bonded in a wafer level state, each of the cut chip-shaped semiconductor substrates is bonded after being cut into chips from the wafer. Compared to, the joining is simplified.

  However, as described in claim 4, the joining member (15) includes a protrusion (16) provided on one of the two semiconductor substrates (11, 12), and the protrusion (16) and the opposing surface ( 11a, 12a) and a configuration having an adhesive (17) provided between them can also be adopted. According to this, since contact between the opposing surfaces (11a, 12a) of the two semiconductor substrates (11, 12) is suppressed, damage to the magnetoelectric conversion elements (13, 14) due to contact is suppressed.

  According to a fifth aspect of the present invention, a mounting member (50) for mounting the sensor chip (10) is provided, and the mounting member (50) has a recess (53) for disposing the sensor chip (10). The formed structure is good. According to this, the arrangement positions of the sensor chip (10) and the mounting member (50) are determined.

  Preferably, one of the two semiconductor substrates (11, 12) is arranged in the recess (53). According to this, the sensor chip (10) can be easily detached from the recess (53) as compared with the configuration in which all of the two semiconductor substrates constituting the sensor chip are disposed in the recess.

  As described in claim 7, the shapes of the two semiconductor substrates (11, 12) are different, and the contour line of the recess (53) is similar to the planar shape of one of the two semiconductor substrates (11, 12). The structure which is is good. According to this, it becomes clear which of the two semiconductor substrates (11, 12) constituting the sensor chip (10) should be arranged in the recess (53).

  As described in claim 8, the cylindrical member (30) has a bottomed cylindrical cap (40), and the mounting member (50) is a tongue (10) for mounting the sensor chip (10). 51) and a support portion (52) for supporting the tongue portion (51), and the end of the cap (40) is joined to the support portion (52), and the sensor chip (10) is mounted. A configuration in which the tongue (51) is disposed in the storage space constituted by the cap (40) and the support (52) is preferable. According to this, since the sensor chip (10) is protected in the storage space, contamination of the magnetoelectric conversion elements (13, 14) due to foreign matters and the characteristics of the magnetoelectric conversion elements (13, 14) due to external temperature changes. The change of is suppressed. As a result, a decrease in the detection sensitivity of the rotation state is suppressed.

  As a specific configuration of the rotation detection device, the mounting member (50) is a resin member in which the terminal (60) is insert-molded, and the sensor chip (10) and the terminal (60) are electrically connected via a conductive member, a plurality of magnetoelectric transducers (13, 14) constitute a half bridge circuit, and a half bridge circuit constitutes a full bridge circuit. Can be adopted.

It is a disassembled perspective view which shows schematic structure of the rotation detection apparatus which concerns on 1st Embodiment. It is a top view which shows the position of a to-be-detected body and a rotation detection apparatus. It is sectional drawing which shows schematic structure of a sensor chip. It is a perspective view which shows the recessed part of a supporting member. It is sectional drawing which shows the modification of a sensor chip. It is a perspective view for demonstrating arrangement | positioning to the recessed part of a sensor chip.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is an exploded perspective view showing a schematic configuration of the rotation detection device according to the first embodiment. FIG. 2 is a top view showing the positions of the detected object and the rotation detection device. FIG. 3 is a cross-sectional view showing a schematic configuration of the sensor chip. FIG. 4 is a perspective view showing a concave portion of the support member.

  The rotation detection device 100 includes a sensor chip 10 and a cylindrical magnet 30 as main parts. As shown in FIG. 1, the rotation detection device 100 according to the present embodiment includes a cap 40, a mounting member 50, and a terminal 60 in addition to the components 10 and 30. As shown in FIG. 2, the sensor chip 10 is disposed in the hollow of the cylindrical magnet 30 and is disposed to face the detection target. The object to be detected is a rotating body made of a magnetic material, and irregularities are formed on the surface thereof. When the irregularities rotate with the rotation of the detected object, the magnetic field formed by the cylindrical magnet 30 changes with the rotation of the irregularities. Then, the magnetic field applied to the sensor chip 10 also changes, and the output signal of the sensor chip 10 also changes. An output signal that depends on the change in the magnetic field (rotation of the detection target) is output to an external element via the terminal 60. In FIG. 2, only main components 10 and 30 of the rotation detection device 100 are illustrated.

  As shown in FIG. 3, the sensor chip 10 joins the two semiconductor substrates 11 and 12, the magnetoelectric conversion elements 13 and 14 formed on the two semiconductor substrates 11 and 12, and the two semiconductor substrates 11 and 12. And a joining member 15. A first magnetoelectric conversion element 13 is formed on the side of the first semiconductor substrate 11 facing the second semiconductor substrate 12, and the second magneto-resistive element 13 is formed on the side of the second semiconductor substrate 12 facing the first semiconductor substrate 11. A magnetoelectric conversion element 14 is formed. In the present embodiment, three first magnetoelectric conversion elements 13 are formed on the first semiconductor substrate 11, and three second magnetoelectric conversion elements 14 are formed on the second semiconductor substrate 12. The three magnetoelectric conversion elements 13 and 14 are arranged in the tangential direction of the rotation direction of the detected object, and the lateral width of the sensor chip 10 (semiconductor substrates 11 and 12) is determined by the three magnetoelectric conversion elements 13 and 14. Has been.

  The magnetoelectric conversion elements 13 and 14 are magnetoresistive effect elements whose resistance values vary depending on the application direction of the magnetic flux, and a plurality of half bridge circuits are configured by the plurality of magnetoelectric conversion elements 13 and 14. The half bridge circuit constitutes a full bridge circuit. The rotation state of the detected object is detected by detecting the rotation of the unevenness of the detected object based on the midpoint voltage of the half bridge circuit constituting the full bridge circuit.

  The joining member 15 is made of a metal material, and its planar shape is annular. Magnetoelectric conversion elements 13 and 14 are arranged in a sealed space constituted by the joining member 15 and the two opposing surfaces 11a and 12a. The two semiconductor substrates 11 and 12 are joined by joining the first wafer having a plurality of the first semiconductor substrates 11 on which the first magnetoelectric conversion elements 13 are formed and the second semiconductor substrate 12 on which the second magnetoelectric conversion elements 14 are formed. This is achieved by directly joining a plurality of second wafers via the joining member 15. After this bonding, the sensor chip 10 is formed by cutting the two wafers bonded via the bonding member 15 for each sensor chip 10 (semiconductor substrates 11 and 12).

  The cylindrical magnet 30 accommodates the sensor chip 10 in the hollow and applies a magnetic field to the sensor chip 10. The cylindrical magnet 30 according to the present embodiment is a cylindrical magnet, and the center of the sensor chip 10 and the center of the detection target are located in the axial direction passing through the center of the cylindrical magnet 30 as shown by a broken line in FIG. Are lined up. The magnetoelectric transducers 13 and 14 are arranged in a direction (tangential direction) orthogonal to the axial direction. The inner diameter of the cylindrical magnet 30 is determined by the lateral width of the sensor chip 10 (the magnetoelectric conversion elements 13 and 14 arranged in the tangential direction).

  The cap 40 is made of a resin material and houses the cylindrical magnet 30. The cap 40 has a bottomed cylindrical shape, and its inner diameter is slightly longer than the outer diameter of the cylindrical magnet 30. The entire circumference of the end of the cap 40 is laser welded to a support member 52 described later, and the cap 40 and the support member 52 constitute a storage space.

  The mounting member 50 includes a tongue portion 51 on which the sensor chip 10 is mounted and a support portion 52 that supports the tongue portion 51. The mounting member 50 is a resin member in which the terminal 60 is insert-molded. Both ends of the terminal 60 are exposed to the outside from the support portion 52, and one end thereof is disposed on the tongue portion 51. As shown in FIG. 4, the tongue 51 has a flat plate shape, and a recess 53 is formed on one surface thereof. The contour line of the recess 53 is similar to the planar shape of the second semiconductor substrate 12, and the second semiconductor substrate 12 is disposed in the recess 53 via an adhesive (not shown). The tongue portion 51 on which the sensor chip 10 is mounted is disposed in the storage space constituted by the cap 40 and the support portion 52 described above. Thereby, the magnetoelectric conversion elements 13 and 14 are doubly protected by the storage space and the sealed space.

  The terminal 60 serves to electrically connect an external element and the sensor chip 10. The terminal 60 and the sensor chip 10 are electrically connected via a conductive member (not shown) such as a wire. The terminal 60 transmits and receives electrical signals between a power terminal that electrically connects the external power source and the sensor chip 10, a ground terminal that electrically connects the ground and the sensor chip 10, and an external element and the sensor chip 10. And a transmission / reception terminal.

  Next, the effect of the rotation detection apparatus 100 according to the present embodiment will be described. As described above, the sensor chip 10 is formed by forming the magnetoelectric conversion elements 13 and 14 on the two bonded semiconductor substrates 11 and 12. Therefore, the lateral width of the sensor chip 10 and the inner diameter of the cylindrical magnet 30 can be shortened compared with a sensor chip in which a magnetoelectric conversion element is formed on one semiconductor substrate. As a result, it is possible to suppress the axial magnetic field from being thinned and to suppress a decrease in detection sensitivity in the rotation state.

  Magnetoelectric conversion elements 13 and 14 are arranged in a sealed space constituted by the joining member 15 and the opposing surfaces 11a and 12a. According to this, since the magnetoelectric conversion elements 13 and 14 are protected in the sealed space, contamination due to foreign matters or the like is suppressed. Further, since it is isolated from the external atmosphere, changes in the characteristics of the magnetoelectric transducers 13 and 14 due to changes in the external temperature are suppressed. As a result, a decrease in the detection sensitivity of the rotation state is suppressed.

  The two semiconductor substrates 11 and 12 are directly bonded via the bonding member 15. According to this, joining is simplified compared to joining each of the cut chip-shaped semiconductor substrates after being cut into chips from the wafer.

  A recess 53 for arranging the sensor chip 10 is formed in the tongue 51. According to this, since the arrangement positions of the sensor chip 10 and the mounting member 50 are determined, the relative positions of the magnetoelectric conversion elements 13 and 14 and the cylindrical magnet 30 are suppressed from shifting. As a result, a deviation in the magnetic field applied to the magnetoelectric conversion elements 13 and 14 is suppressed.

  Of the two semiconductor substrates 11 and 12, the second semiconductor substrate 12 is disposed in the recess 53. According to this, the sensor chip 10 can be easily detached from the recess 53 as compared with the configuration in which all of the two semiconductor substrates constituting the sensor chip are disposed in the recess.

  The magnetoelectric conversion elements 13 and 14 are double protected by the storage space and the sealed space. According to this, as compared with the configuration in which the magnetoelectric conversion elements 13 and 14 are protected only by either the storage space or the sealed space, the magnetoelectric conversion elements 13 and 14 are contaminated by foreign matters or the like and the external temperature changes. Changes in the characteristics of the magnetoelectric conversion elements 13 and 14 are suppressed. As a result, a decrease in the detection sensitivity of the rotation state is suppressed.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  In this embodiment, the joining member 15 is a metal material, and the example in which the two semiconductor substrates 11 and 12 are directly joined via the joining member 15 is shown. However, as shown in FIG. 5, the bonding member 15 includes a plurality of protrusions 16 provided on the second semiconductor substrate 12, and an adhesive 17 provided between the protrusions 16 and the facing surface 11a. It is also possible to adopt a configuration in which the semiconductor substrates 11 and 12 are bonded and fixed via the adhesive 17. In this case, since the contact between the opposing surfaces 11a and 12a of the two semiconductor substrates 11 and 12 is suppressed, damage to the magnetoelectric conversion elements 13 and 14 due to the contact is suppressed. Although not shown, the bonding member 15 includes a plurality of protrusions 16 provided on the first semiconductor substrate 11 and an adhesive 17 provided between the protrusions 16 and the facing surface 12a. Can also be adopted. FIG. 5 is a cross-sectional view showing a modified example of the sensor chip.

  In the present embodiment, as shown in FIGS. 2 and 3, the example in which the shapes of the two semiconductor substrates 11 and 12 are the same is shown. However, as shown in FIG. 6, the shapes of the two semiconductor substrates 11 and 12 may be different. In FIG. 6, the second semiconductor substrate 12 is smaller than the first semiconductor substrate 11, and the second semiconductor substrate 12 is arranged in the recess 53. According to this, it becomes clear which of the two semiconductor substrates 11 and 12 constituting the sensor chip 10 should be arranged in the recess 53. FIG. 6 is a perspective view for explaining the arrangement of the sensor chip in the recess.

  In the present embodiment, an example in which three first magnetoelectric conversion elements 13 are formed on the first semiconductor substrate 11 and three second magnetoelectric conversion elements 14 are formed on the second semiconductor substrate 12 has been described. However, the number of magnetoelectric conversion elements 13 and 14 formed on each semiconductor substrate 11 and 12 is not limited to the above example, and may be one or more. That is, the total number of the magnetoelectric conversion elements 13 and 14 may be two or more.

DESCRIPTION OF SYMBOLS 10 ... Sensor chip 11 ... 1st semiconductor substrate 12 ... 2nd semiconductor substrate 13 ... 1st magnetoelectric conversion element 14 ... 2nd magnetoelectric conversion element 15 ... Joining member 30 ... Cylindrical magnet 40 ... cap 50 ... mounting member 60 ... terminal 100 ... rotation detector

Claims (11)

A sensor chip (10) having a plurality of magnetoelectric transducers (13, 14);
A cylindrical magnet (30) provided with the sensor chip (10) in the hollow,
The rotation detection device detects a rotation state of the detected object by detecting a change in the magnetic field formed by the cylindrical magnet (30) due to the rotation of the detected object by the magnetoelectric transducer (13, 14). And
The sensor chip (10) includes a semiconductor substrate (11) on which the magnetoelectric conversion element (13) is formed, and a semiconductor substrate (12) on which the magnetoelectric conversion element (14) is formed.
The rotation detecting device, wherein the two semiconductor substrates (11, 12) are joined via a joining member (15). The joining member (15) has an annular shape,
The magnetoelectric conversion elements (13, 14) are disposed in a sealed space formed by the joining member (15) and opposing surfaces (11a, 12a) of the two semiconductor substrates (11, 12). The rotation detection device according to claim 1.   The rotation detecting device according to claim 1 or 2, wherein the joining member (15) and the semiconductor substrate (11, 12) are directly joined.   The bonding member (15) includes a protrusion (16) provided on one of the two semiconductor substrates (11, 12), and between the protrusion (16) and the facing surface (11a, 12a). The rotation detection device according to claim 1, further comprising an adhesive (17) provided. A mounting member (50) for mounting the sensor chip (10);
The rotation detecting device according to any one of claims 1 to 4, wherein the mounting member (50) is formed with a recess (53) for disposing the sensor chip (10).   6. The rotation detection device according to claim 5, wherein one of the two semiconductor substrates (11, 12) is arranged in the recess (53). The two semiconductor substrates (11, 12) have different shapes,
The rotation detecting device according to claim 6, wherein the contour line of the concave portion (53) is similar to the planar shape of one of the two semiconductor substrates (11, 12). A bottomed cylindrical cap (40) for accommodating the cylindrical magnet (30);
The mounting member (50) includes a tongue (51) for mounting the sensor chip (10), and a support (52) for supporting the tongue (51).
An end portion of the cap (40) is joined to the support portion (52), and a tongue portion (51) on which the sensor chip (10) is mounted is formed by the cap (40) and the support portion (52). The rotation detection device according to any one of claims 5 to 7, wherein the rotation detection device is arranged in a configured storage space. The mounting member (50) is a resin member in which the terminal (60) is insert-molded,
The rotation detection device according to any one of claims 5 to 8, wherein the sensor chip (10) and the terminal (60) are electrically connected via a conductive member.   The rotation detecting device according to any one of claims 1 to 9, wherein a plurality of magnetoelectric transducers (13, 14) constitute a half bridge circuit.   The rotation detection apparatus according to claim 10, wherein a full bridge circuit is configured by the half bridge circuit.

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