Magnetic sensor

Abstract

The present invention relates to a magnetic sensor which can improve the detection precision of a weak magnetic field and can be downsized. A magnetic sensor is provided with a magnetic body changing the direction of a magnetic field input to a magnetoresistance effect element in the vicinity of the magnetoresistance effect element in which the resistance value changes according to the direction of the input magnetic field, the magnetic body has a mean for changing the direction of a magnetic field on the surface at a side where the magnetoresistance effect element is formed. The chamfer part of the magnetic body may be chamfered with a shape having at least one flat surface.

Claims

1. A magnetic sensor for detecting an intensity of a magnetic field comprising: a magnetoresistance effect element placed on a placement surface; and a magnetic body (1) placed on the placement surface and spaced from the magnetoresistance effect element when viewed in a direction perpendicular to the placement surface such that the magnetoresistance effect element is located outside the periphery of the magnetic body when viewed in the direction perpendicular to the placement surface and (2) that has a polygon shape with at least one chamfered corner in a cross-section parallel to the placement surface, wherein the magnetic body changes the direction of an input magnetic field input to the magnetoresistance effect element, a resistance value of the magnetoresistance effect element changes according to the direction of the input magnetic field, and the magnetoresistance effect element and the magnetic body are configured and positioned relative to each other such that the magnetic field enters the magnetic body in a direction transverse to the placement surface and is guided out of the magnetic body and to the magnetoresistance effect element such that the at least one chamfered corner causes the input magnetic field in the vicinity of the at least one chamfered corner to bend towards a direction in which magnetic induction occurs in the magnetoresistance effect element to increase the intensity of the input magnetic field.

2. The magnetic sensor according to claim 1, wherein, the magnetic body is a soft magnetic body.

3. The magnetic sensor according to claim 1, wherein the magnetic body does not overlap any part of the magnetoresistance effect element when viewed in the direction perpendicular to the placement surface.

4. The magnetic sensor according to claim 1, wherein the magnetic body has a rectangular shape with four corners.

5. A magnetic sensor for detecting an intensity of a magnetic field comprising: a pair of spaced magnetoresistance effect elements placed on a placement surface; and a magnetic body positioned between the pair of magnetoresistance effect elements when viewed in a direction perpendicular to the placement surface, the magnetic body not overlapping any part of the magnetoresistance effect elements when viewed in the direction perpendicular to the placement surface, wherein the magnetic body changes the direction of an input magnetic field input to the magnetoresistance effect elements, resistance values of the magnetoresistance effect elements change according to the direction of the input magnetic field, the magnetic body has a polygon shape with at least one chamfered corner in a cross-section parallel to the placement surface, and the magnetoresistance effect elements and the magnetic body are configured and positioned relative to each other such that the magnetic field enters the magnetic body in a direction transverse to the placement surface and is guided out of the magnetic body and to the magnetoresistance effect elements such that the at least one chamfered corner causes the input magnetic field in the vicinity of the at least one chamfered corner to bend towards a direction in which magnetic induction occurs in the magnetoresistance effect elements to increase the intensity of the input magnetic field.

6. The magnetic sensor according to claim 5, wherein the chamfered corner of the magnetic body constitutes a flat surface extending in the direction perpendicular to the placement surface.

7. The magnetic sensor according to claim 5, wherein the chamfered corner of the magnetic body constitutes a concave surface extending in the direction perpendicular to the placement surface.

8. The magnetic sensor according to claim 5, wherein, the magnetic body is a soft magnetic body.

9. The magnetic sensor according to claim 6, wherein, the magnetic body is a soft magnetic body.

10. The magnetic sensor according to claim 7, wherein, the magnetic body is a soft magnetic body.

11. The magnetic sensor according to claim 5, wherein the magnetic body has a rectangular shape with four corners in the cross-section.

12. The magnetic sensor according to claim 5, wherein all corners of the magnetic body are chamfered corners.

13. The magnetic sensor according to claim 5, wherein the magnetic body has a plurality of corners formed by side faces and all of the corners are other than a 90° corner formed by two of the side faces.

14. The magnetic sensor according to claim 5, wherein: the magnetic body has first and second opposing side surfaces; and the first side surface faces a first of the pair of spaced magnetoresistance effect elements and the second side surface faces a second of the pair of spaced magnetoresistance effect elements.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a view showing the configuration of the GMR chip.

(2) FIG. 2 is a diagram showing the characteristic of the GMR element.

(3) FIG. 3 is a view showing the configuration of the conventional magnetic sensor (the surface involving X-Z axis).

(4) FIG. 4 is a view showing the configuration of the conventional magnetic sensor (the surface involving X-Y axis).

(5) FIG. 5 is a schematic view showing the magnetic flux introduced to the GMR element part in the example of prior art (on the surface involving X-Z axis).

(6) FIG. 6 is a schematic view showing the magnetic flux introduced to the GMR element part in the example of prior art (on the surface involving X-Y axis).

(7) FIG. 7 is a view showing the configuration of the magnetic sensor in Embodiment 1 (on the surface involving X-Z axis).

(8) FIG. 8 is a view showing the configuration of the magnetic sensor in Embodiment 1 (on the surface involving X-Y axis).

(9) FIG. 9 is a schematic view showing the magnetic flux introduced to the GMR element part in Embodiment 1.

(10) FIG. 10 shows the stimulation results in the example of prior art and Embodiment 1 about the intensity of the magnetic field at the magnetoresistance effect element part in the X-axis direction.

(11) FIG. 11 is a view showing the configuration of the magnetic sensor in Embodiment 2 (on the surface involving X-Z axis).

(12) FIG. 12 is a view showing the configuration of the magnetic sensor in Embodiment 2 (on the surface involving X-Y axis).

(13) FIG. 13 is a schematic view showing the magnetic flux introduced to the GMR element part in Embodiment 2.

(14) FIG. 14 shows the stimulation results in the example of prior art and Embodiment 2 about the intensity of the magnetic field at the magnetoresistance effect element part in the X-axis direction.

(15) FIG. 15 is a view showing the configuration of the magnetic sensor in Embodiment 3 (on the surface involving X-Z axis).

(16) FIG. 16 is a view showing the configuration of the magnetic sensor in Embodiment 3 (on the surface involving X-Y axis).

(17) FIG. 17 is a schematic view showing the magnetic flux introduced to the GMR element part in Embodiment 3.

(18) FIG. 18 shows the stimulation results in the example of prior art and Embodiment 3 about the intensity of the magnetic field at the magnetoresistance effect element part in the X-axis direction.

(19) FIG. 19 is a view showing the configuration of the magnetic sensor in Embodiment 4 (on the surface involving X-Z axis).

(20) FIG. 20 is a view showing the configuration of the magnetic sensor in Embodiment 4 (on the surface involving X-Y axis).

(21) FIG. 21 is a schematic view showing the magnetic flux introduced to the GMR element part in Embodiment 4.

(22) FIG. 22 shows the stimulation results in the example of prior art and Embodiment 4 about the intensity of the magnetic field at the magnetoresistance effect element part in the X-axis direction.

DETAILED DESCRIPTION OF EMBODIMENTS

(23) The specific configuration in the present invention will be described in the following embodiments. Hereinafter, the basic configuration of the magnetic sensor in the present invention will be described in Embodiment 1, and the configuration of the magnetic sensor in the present invention to be specifically applied will be described in Embodiments 2 to 4.

(24) The GMR element is described as an example of the magnetoresistance effect element, but the element involving the magneto-resistance effect can also be used, including the TMR element, AMR element and the like.

Embodiment 1

(25) The first embodiment of the present invention will be described with reference to FIG. 7 to FIG. 10. FIG. 7 is a view showing the configuration of the magnetic sensor according to the present embodiment on the surface involving X-Z axis. FIG. 8 is a view showing the configuration of the magnetic sensor according to the present embodiment on the surface involving X-Y axis. FIG. 9 is a schematic view showing the magnetic field entering the GMR element part through the magnetic body in the present embodiment. FIG. 10 shows the stimulation results in the example of prior art and the present embodiment about the intensity of the magnetic field at the magnetoresistance effect element part in the X-axis direction.

(26) [Configuration]

(27) The shape of the soft magnetic body according to the present embodiment will be described with reference to FIG. 7 and FIG. 8. GMR elements 111 and 112 are formed in GMR chip 110. Further, these GMR elements form a bridge circuit. In the vicinity of the bridge circuit, magnetic body 121 changing the direction of the magnetic field input to the magnetoresistance effect element is disposed. In addition, on the cross-section involving X-Y axis, chamfer part 131 is disposed on the corner part of magnetic body 121.

(28) Further, chamfer part 131 of magnetic body 121 preferably has one flat surface.

(29) Magnetic body 121 is the soft magnetic body made of the material such as the ferrite material, the permalloy (Ni—Fe alloy), Sendust (Fe—Si—Al alloy) or the like. The material is not restricted as long as magnetic body 121 functions to change the direction of magnetic field H.

(30) Further, magnetic body 121 is preferably composed of one component. However, as long as magnetic body 121 is capable of changing the direction of magnetic field H, the number of the components to constitute magnetic body 121 is not particularly restricted.

(31) [Function]

(32) Hereinafter, magnetic field H introduced to GMR element parts 111 and 112 through the configuration mentioned above will be described with reference to FIG. 9. Similar to that in the example of prior art, the magnetic field entering magnetic body 121 from the front external side of the figure in Z-axis direction is bended by magnetic body 121 and is introduced into the interior of magnetic body 121.

(33) Magnetic field H introduced into the interior of magnetic body 121 is guided towards the GMR element disposing side by the chamfer shape in the vicinity of chamfer part 131 of magnetic body 121 and is then bended towards the direction where the magnetic induction occurs in the GMR element. With such a function, the component of magnetic field H in the X-axis direction is increased to improve the detection precision of the magnetic sensor, wherein the magnetic induction occurs in the X-axis direction in the GMR element.

(34) With reference to FIG. 10, a simulation is performed to predict the intensity of magnetic field H introduced to GMR element parts 111 and 112 through the configuration mentioned above, and the result is described and compared against that from the example of prior art. It can be confirmed in Embodiment 1 that the intensity of magnetic field H introduced to GMR element parts 111 and 112 is increased compared to that in the example of prior art.

(35) With the function mentioned above, the detection precision of the magnetic sensor can be improved by increasing the intensity of the magnetic field at the GMR element part.

Embodiment 2

(36) The second embodiment of the present invention will be described with reference to FIG. 11 to FIG. 14. FIG. 11 is a view showing the configuration of the magnetic sensor according to the present embodiment on the surface involving X-Z axis. FIG. 12 is a view showing the configuration of the magnetic sensor according to the present embodiment on the surface involving X-Y axis. FIG. 13 is a schematic view showing the magnetic field entering the GMR element part through the magnetic body in the present embodiment. FIG. 14 shows the stimulation results in the example of prior art and the present embodiment about the intensity of the magnetic field at the magnetoresistance effect element part in the X-axis direction.

(37) [Configuration]

(38) The shape of the soft magnetic body according to the present embodiment will be described with reference to FIG. 11 and FIG. 12. GMR elements 211 and 212 are formed in GMR chip 210. Further, these GMR elements form a bridge circuit. In the vicinity of the bridge circuit, magnetic body 221 changing the direction of the magnetic field input to the magnetoresistance effect element is disposed. In addition, on the cross-section involving X-Y axis, chamfer part 231 is disposed on the corner part of magnetic body 221.

(39) Further, on the plane involving X-axis and Y-axis, the shape of chamfer part 231 of magnetic body 221 preferably has two flat surfaces. However, the shape of chamfer part 231 may have two or more flat surfaces as long as chamfer part 231 functions to change the direction of magnetic field H.

(40) Magnetic body 221 is the soft magnetic body made of the material such as the ferrite material, the permalloy (Ni—Fe alloy), Sendust (Fe—Si—Al alloy) or the like. The material is not restricted as long as magnetic body 221 functions to change the direction of magnetic field H.

(41) Further, magnetic body 221 is preferably composed of one component. However, as long as magnetic body 221 is capable of changing the direction of magnetic field H, the number of the components to constitute magnetic body 221 is not particularly restricted.

(42) [Function]

(43) Hereinafter, magnetic field H introduced to GMR element parts 211 and 212 through the configuration mentioned above will be described with reference to FIG. 13. Similar to that in the example of prior art, the magnetic field entering magnetic body 221 from the front external side of the figure in Z-axis direction is bended by magnetic body 221 and is introduced into the interior of magnetic body 221.

(44) Magnetic field H introduced into the interior of magnetic body 221 is guided towards the GMR element disposing side by the chamfer shape in the vicinity of chamfer part 231 of magnetic body 221 and is then bended towards the direction where the magnetic induction occurs in the GMR element. With such a function, the component of magnetic field H in the X-axis direction is increased to improve the detection precision of the magnetic sensor, wherein the magnetic induction occurs in the X-axis direction in the GMR element.

(45) With reference to FIG. 14, a simulation is performed to predict the intensity of magnetic field H introduced to GMR element parts 211 and 212 through the configuration mentioned above, and the result is described and compared against that from the example of prior art. It can be confirmed in Embodiment 2 that the intensity of magnetic field H introduced to GMR element parts 211 and 212 is increased compared to that in the example of prior art.

(46) With the function mentioned above, the detection precision of the magnetic sensor can be improved by increasing the intensity of the magnetic field at the GMR element part.

Embodiment 3

(47) The third embodiment of the present invention will be described with reference to FIG. 15 to FIG. 18. FIG. 15 is a view showing the configuration of the magnetic sensor according to the present embodiment on the surface involving X-Z axis. FIG. 16 is a view showing the configuration of the magnetic sensor according to the present embodiment on the surface involving X-Y axis. FIG. 17 is a schematic view showing the magnetic field entering the GMR element part through the magnetic body in the present embodiment. FIG. 18 shows the stimulation results in the example of prior art and the present embodiment about the intensity of the magnetic field at the magnetoresistance effect element part in the X-axis direction.

(48) [Configuration]

(49) The shape of the soft magnetic body according to the present embodiment will be described with reference to FIG. 15 and FIG. 16. GMR elements 311 and 312 are formed in GMR chip 310. Further, these GMR elements form a bridge circuit. In the vicinity of the bridge circuit, magnetic body 321 changing the direction of the magnetic field input to the magnetoresistance effect element is disposed. In addition, on the cross-section involving X-Y axis, chamfer part 331 is disposed on the corner part of magnetic body 321.

(50) Further, on the plane involving the X-axis and the Y-axis, chamfer part 331 of magnetic body 321 preferably has an arc like shape bulging towards the center direction of magnetic body 321. However, the arc like shape can be used for part or all of chamfer parts 331 as long as chamfer part 331 functions to change the direction of magnetic field H. Further, the arc like shape and the polygon like shape can be used in combination for chamfer part 331.

(51) Magnetic body 321 is the soft magnetic body made of the material such as the ferrite material, the permalloy (Ni—Fe alloy), Sendust (Fe—Si—Al alloy) or the like. The material is not restricted as long as magnetic body 221 functions to change the direction of magnetic field H.

(52) Further, magnetic body 321 is preferably composed of one component. However, as long as magnetic body 321 is capable of changing the direction of magnetic field H, the number of the components to constitute magnetic body 321 is not particularly restricted.

(53) [Function]

(54) Hereinafter, magnetic field H introduced to GMR element parts 311 and 312 through the configuration mentioned above will be described with reference to FIG. 17. Similar to that in the example of prior art, the magnetic field entering magnetic body 321 from the front external side of the figure in Z-axis direction is bended by magnetic body 321 and is introduced into the interior of magnetic body 321.

(55) Magnetic field H introduced into the interior of magnetic body 321 is guided towards the GMR element disposing side by the chamfer shape in the vicinity of chamfer part 331 of magnetic body 321 and is then bended towards the direction where the magnetic induction occurs in the GMR element. With such a function, the component of magnetic field H in the X-axis direction is increased to improve the detection precision of the magnetic sensor, wherein the magnetic induction occurs in the X-axis direction in the GMR element.

(56) With reference to FIG. 18, a simulation is performed to predict the intensity of magnetic field H introduced to GMR element parts 311 and 312 through the configuration mentioned above, and the result is described and compared against that from the example of prior art. It can be confirmed in Embodiment 3 that the intensity of magnetic field H introduced to GMR element parts 311 and 312 is increased compared to that in the example of prior art.

(57) With the function mentioned above, the detection precision of the magnetic sensor can be improved by increasing the intensity of the magnetic field at the GMR element part.

Embodiment 4

(58) The fourth embodiment of the present invention will be described with reference to FIG. 19 to FIG. 22. FIG. 19 is a view showing the configuration of the magnetic sensor according to the present embodiment on the surface involving X-Z axis. FIG. 20 is a view showing the configuration of the magnetic sensor according to the present embodiment on the surface involving X-Y axis. FIG. 21 is a schematic view showing the magnetic field entering the GMR element part through the magnetic body in the present embodiment. FIG. 22 shows the stimulation results in the example of prior art and the present embodiment about the intensity of the magnetic field at the magnetoresistance effect element part in the X-axis direction.

(59) [Configuration]

(60) The shape of the soft magnetic body according to the present embodiment will be described with reference to FIG. 19 and FIG. 20. GMR elements 411 and 412 arc formed in GMR chip 410. Further, these GMR elements form a bridge circuit in the vicinity of the bridge circuit, magnetic body 421 changing the direction of the magnetic field input to the magnetoresistance effect element is disposed. In addition, on the cross-section involving X-Y axis, chamfer part 431 is disposed on the corner part of magnetic body 421.

(61) Further, on the plane involving the X-axis and the Y-axis, chamfer part 431 of magnetic body 421 preferably has an arc like shape bulging towards the outside direction of magnetic body 421. However, the arc like shape can be used for part or all of chamfer parts 431 as long as chamfer part 431 functions to change the direction of magnetic field H. Further, the arc like shape and the polygon like shape can be used in combination for chamfer part 431.

(62) Magnetic body 421 is the soft magnetic body made of the material such as the ferrite material, the permalloy (Ni—Fe alloy), Sendust (Fe—Si—Al alloy) or the like. The material is not restricted as long as magnetic body 221 functions to change the direction of magnetic field H.

(63) Further, magnetic body 421 is preferably composed of one component. However, as long as magnetic body 421 is capable of changing the direction of magnetic field H, the number of the components to constitute magnetic body 421 is not particularly restricted.

(64) [Function]

(65) Hereinafter, magnetic field H introduced to GMR element parts 411 and 412 through the configuration mentioned above will be described with reference to FIG. 21. Similar to that in the example of prior art, the magnetic field entering magnetic body 421 from the front external side of the figure in Z-axis direction is bended by magnetic body 421 and is introduced into the interior of magnetic body 421.

(66) Magnetic field H introduced into the interior of magnetic body 421 is guided towards the GMR element disposing side by the chamfer shape in the vicinity of chamfer part 431 of magnetic body 421 and is then bended towards the direction where the magnetic induction occurs in the GMR element. With such a function, the component of magnetic field H in the X-axis direction is increased to improve the detection precision of the magnetic sensor, wherein the magnetic induction occurs in the X-axis direction in the GMR element.

(67) With reference to FIG. 22, a simulation is performed to predict the intensity of magnetic field H introduced to GMR element parts 411 and 412 through the configuration mentioned above, and the result is described and compared against that from the example of prior art. It can be confirmed in Embodiment 4 that the intensity of magnetic field H introduced to GMR element parts 411 and 412 is increased compared to that in the example of prior art.

(68) With the function mentioned above, the detection precision of the magnetic sensor can be improved by increasing the intensity of the magnetic field at the GMR element part.

INDUSTRIAL APPLICATION

(69) The present invention can be applied to various measuring devices such as the magnetic sensor, the galvanometer and the encoder. Thus, the present invention can be utilized in the industry.

DESCRIPTION OF REFERENCE NUMERALS

(70) 1 GMR chip 10 GMR chip in example of prior art 11, 12 element disposing part in example of prior art 21 magnetic body in example of prior art 110 GMR chip in Embodiment 1 111, 112 element disposing part in Embodiment 1 121 magnetic body in Embodiment 1 131 chamfer part of magnetic body in Embodiment 1 210 GMR chip in Embodiment 2 211, 212 element disposing part in Embodiment 2 221 magnetic body in Embodiment 2 231 chamfer part of magnetic body in Embodiment 2 310 GMR chip in Embodiment 3 311, 312 element disposing part in Embodiment 3 321 magnetic body in Embodiment 3 331 chamfer part of magnetic body in Embodiment 3 410 GMR chip in Embodiment 4 411, 412 element disposing part in Embodiment 4 421 magnetic body in Embodiment 4 431 chamfer part of magnetic body in Embodiment 4 A fixed direction of magnetization H magnetic field