JP2007309671A - Magnetic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic device which can be manufactured at low cost, using a simple manufacturing process, and can be miniaturized also. <P>SOLUTION: The magnetic device 10 has a first magnetic field application means 11, a second magnetic field application means 12, and a magnetometric sensor 13. The first means 11 forms a magnetic field ML in a direction of heading from one surface 11a towards the other surface 11b; whereas the second means 12 has a magnetic field MR in a direction of heading towards one surface 12a from the other surface 12b. According to these magnetic fields ML and MR, a substantially annular bias magnetic field MB is formed between the first means 11 and the second means 12, arranged adjoining each other. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a magnetic device including a magnetic sensor and a magnetic field applying unit.

  In recent years, for the purpose of cost reduction and chip component reduction, a small and lightweight magnetic sensor such as a magnetic impedance element using a magnetic thin film has been proposed. For example, in the invention described in Patent Document 1, a plurality of magnetic sensitive parts made of soft magnetic thin films formed linearly on one surface of a substrate are arranged in parallel, and a sheet-like thin film is formed so as to cover these magnetic sensitive parts. A magneto-impedance effect element is described in which a magnet is provided and a bias magnetic field is applied to a plurality of magnetic sensing parts. Patent Document 2 describes a magnetic detecting element in which a magnetic film is formed along the surface of a printed circuit board and a bias magnetic field is applied to the magnetic film by a coil formed so as to surround the magnetic film. ing.

In Patent Document 3, two thin film magnetic cores electrically connected in series are arranged in parallel on a substrate, and a thin film bias coil is provided so as to surround each of these two thin film magnetic cores. A magnetic sensor element formed and configured to apply a bias magnetic field to the thin film magnetic core by the thin film bias coil is described.
Japanese Patent No. 3650575 Japanese Patent No. 3096413 Japanese Patent No. 3341237

  However, in each of the inventions described in Patent Documents 1 to 3, it is necessary to form a bias magnetic field applying means for applying a bias magnetic field adjacent to the magnetic sensor, and the arrangement of the bias magnetic field applying means and the magnetic sensor is required. However, there was a problem that miniaturization was difficult. Moreover, the structure of the whole magnetic sensor containing a bias magnetic field application means is complicated, and there existed a subject that manufacturing cost started.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a magnetic device that can be manufactured at a low cost by a simple manufacturing process and can be miniaturized.

The magnetic device according to claim 1 of the present invention is a magnetic device including at least a first magnetic field applying unit, a second magnetic field applying unit, and a magnetic sensor, wherein the first magnetic field applying unit and the second magnetic field are provided. The applying means forms one annular bias magnetic field, and the magnetic sensor is arranged such that its magnetic sensitive direction is along the direction of the bias magnetic field.
A magnetic device according to a second aspect of the present invention is the magnetic device according to the first aspect, characterized in that the magnetic sensing direction of the magnetic sensor is arranged in an annular central region of the bias magnetic field.
A magnetic device according to a third aspect of the present invention is characterized in that, in the first aspect, a magnetic body is further arranged so as to overlap a part of the first magnetic field applying means and the second magnetic field applying means.
According to a fourth aspect of the present invention, in the magnetic device according to the first aspect, the first magnetic field applying means and the second magnetic field applying means are planar spiral coils.

  According to the magnetic device of the present invention, by providing the two magnetic field applying means, the first magnetic field applying means and the second magnetic field applying means, a series of substantially annular magnetic fluxes flowing in one direction can be formed. By arranging the magnetic sensor along the magnetic field, even if the magnetic sensor has a magnetic sensitive direction other than perpendicular to the first magnetic field applying means and the second magnetic field applying means, It is possible to detect the magnetic field strength along.

  Further, if the magnetic sensor is arranged along a substantially annular series of magnetic fluxes formed by the first magnetic field applying means and the second magnetic field applying means, the first magnetic field applying means, the second magnetic field applying means and the magnetic sensor are separated from each other. Therefore, it is possible to expand the degree of freedom in designing the magnetic device, such as arranging the two magnetic field applying means in three dimensions, and forming according to the arrangement position of the two magnetic field applying means. Since the spread of the bias magnetic field can be controlled, an optimum bias magnetic field can be applied to the magnetic sensor in accordance with the arrangement position of the magnetic sensor. Furthermore, since each may be formed separately and combined to form a magnetic sensor, a magnetic device that can be manufactured at low cost by a simple manufacturing process can be provided. Further, since the relative positions of the two magnetic field applying means can be changed, the layout can be freely performed and the degree of freedom in design is improved.

  Hereinafter, an example of a magnetic device according to the present invention will be described with reference to the drawings. Note that the present invention is not limited to such an embodiment. FIG. 1 is a perspective view and a top view showing an example of a magnetic device of the present invention. The magnetic device 10 of the present invention includes a first magnetic field applying unit 11, a second magnetic field applying unit 12, and a magnetic sensor 13. In the first magnetic field applying unit 11, a magnetic field ML is formed in a direction from the one surface 11a to the other surface 11b shown in FIG. The second magnetic field applying unit 12 forms a magnetic field MR in a direction from the other surface 12b toward the one surface 12a.

  Due to these magnetic fields ML and MR, a substantially annular bias magnetic field MB is formed between the first magnetic field applying means 11 and the second magnetic field applying means 12 arranged adjacent to each other. The bias magnetic field MB is directed from the one surface 12a of the second magnetic field applying means 12 to the one surface 11a of the first magnetic field applying means 11, and returned from the other surface 11b of the first magnetic field applying means 11 to the other surface 12b of the second magnetic field applying means 12. A series of substantially annular magnetic fluxes flowing in one direction are formed.

  The magnetic sensor 13 detects the magnetic field strength in the magnetic sensitive direction S. The magnetic sensor 13 is arranged with respect to the first magnetic field applying means 11 and the second magnetic field applying means 12 so that the magnetic sensing direction S is along the direction F in which the magnetic flux forming the bias magnetic field MB is directed. As a result, a bias magnetic field MB along the magnetic sensing direction S is applied to the magnetic sensor 13.

  According to the magnetic device of the present invention configured as described above, the bias magnetic field MB is applied to the magnetic sensor 13 by the first magnetic field applying means 11 and the second magnetic field applying means 12, and the magnetic field along the magnetic sensitive direction S is changed. Intensity can be detected accurately.

  And by providing the two magnetic field applying means, the first magnetic field applying means 11 and the second magnetic field applying means 12, a series of substantially annular magnetic fluxes flowing in one direction can be formed, and the magnetic sensor along this substantially annular magnetic flux 13 is arranged along the magnetic sensing direction S regardless of the angle of the magnetic sensing direction S of the magnetic sensor 13 with respect to the first magnetic field applying means 11 and the second magnetic field applying means 12. It becomes possible to detect the magnetic field strength.

  Further, if the magnetic sensor 13 is arranged along a substantially annular series of magnetic fluxes formed by the first magnetic field applying means 11 and the second magnetic field applying means 12, the first magnetic field applying means 11, the second magnetic field applying means 12, and Since the magnetic sensors 13 may be separated from each other, the magnetic sensors 13 may be formed by combining them separately to constitute the magnetic sensor 13, and the magnetic sensor 13 can be manufactured at a low cost by simplifying the manufacturing process. .

  The first magnetic field applying unit 11 and the second magnetic field applying unit 12 may be any devices as long as they can generate a magnetic field. For example, a permanent magnet or an electromagnet made of a coiled conductor may be used. The first magnetic field application unit 11 and the second magnetic field application unit 12 do not need to be arranged on the same plane, and may be arranged on different planes.

  The magnetic sensor 13 only needs to change its output in accordance with the magnetic field strength. For example, the magnetic sensor 13 may be any one in which a soft magnetic film is extended in a meander shape along the magnetic sensitive direction on an insulator. . The first magnetic field applying unit 11, the second magnetic field applying unit 12, and the magnetic sensor 13 may be formed on a support having an arbitrary shape such as a multilayer substrate.

  FIG. 2 is a perspective view showing another example of the magnetic device of the present invention. 3 is a cross-sectional view taken along line AA in FIG. The magnetic device 20 includes a first magnetic field applying unit 21 and a second magnetic field applying unit 22 formed on one surface (lower surface) 24a of the substrate 24, and a magnetic sensor 23 disposed on the other surface (upper surface) 24b of the substrate 24. Have. The substrate 24 may be made of an insulating resin or the like.

  The first magnetic field applying means 21 and the second magnetic field applying means 22 may be spiral coils 21 a and 22 a formed by spreading a conductive film such as a metal along the one surface 24 a of the substrate 24 in a planar shape. The winding directions of the spiral coils 21a and 22a are formed so as to be opposite to each other, and one ends of the spiral coils 21a and 22a are electrically connected to each other.

  With such a configuration, the first magnetic field applying unit 21 and the second magnetic field applying unit 22 generate magnetic fields in opposite directions by passing a current between the terminals 21b and 22b of the spiral coils 21a and 22a. Between the first magnetic field applying means 21 and the second magnetic field applying means 22, a bias magnetic field MB made up of a series of substantially annular magnetic fluxes flowing in one direction is formed.

  The magnetic sensor 23 only needs to have a soft magnetic film 23b formed on one surface of the insulator 23a, for example. Such a soft magnetic film 23b is formed in, for example, a meander shape (a zigzag folded shape), and its longitudinal direction is a magnetosensitive direction S. The magnetic sensor 23 having such a configuration is arranged such that the magnetic sensing direction S is along the direction of the substantially annular magnetic flux forming the bias magnetic field MB formed by the first magnetic field applying means 21 and the second magnetic field applying means 22. Thereby, a bias magnetic field MB along the magnetic sensing direction S is applied to the magnetic sensor 23, and the magnetic field strength in the magnetic sensing direction S can be detected with high accuracy.

  Magnetic bodies 25a and 25b are disposed between the magnetic sensor 23 and the other surface 24b of the substrate 24, respectively. Such magnetic bodies 25a and 25b may be disposed so as to overlap the outer regions of the spiral coils 21a and 22a. By covering the outer regions of the spiral coils 21a and 22a with the magnetic bodies 25a and 25b, the spiral coils 21a and 22a are arranged with respect to the magnetic sensor 23 arranged so as to be located inward from the vicinity of the center of the spiral coils 21a and 22a. The influence of an extra leakage magnetic field other than the bias magnetic field MB generated at 22a can be cut off. In addition, electrodes 26 a and 26 b that are electrically connected to the soft magnetic film 23 b of the magnetic sensor 23 may be formed between the magnetic sensor 23 and the other surface 24 b of the substrate 24.

  The magnetic device 20 configured as described above can form a bias magnetic field MB composed of a series of substantially magnetic fluxes by the first magnetic field applying means 21 and the second magnetic field applying means 22 which are two magnetic field applying means. By aligning the magnetic sensing direction S of the magnetic sensor 23 along the direction of the magnetic flux of the magnetic field MB, the magnetic field strength in the magnetic sensing direction S can be detected with high accuracy.

  Then, the first magnetic field applying means 21 and the second magnetic field applying means 22 are composed of spiral coils 21a and 22a extending in a plane along the substrate 24, whereby the entire magnetic device 20 is reduced in size and thickness. be able to. Further, by covering the outer regions of the spiral coils 21a and 22a with the magnetic bodies 25a and 25b, the magnetic sensor 23 is shielded from the influence of an extra leakage magnetic field other than the bias magnetic field MB generated by the spiral coils 21a and 22a. Therefore, the magnetic field detection accuracy of the magnetic sensor 23 can be further enhanced.

  The two magnetic field applying means can also deflect the direction of the magnetic flux forming the bias magnetic field to be generated by changing the mutual position and magnetic field generating force. In FIG. 4A, the first magnetic field applying means 31 and the second magnetic field applying means 32 are constituted by spiral coils having the same number of turns on the same plane along one surface of the substrate 33. Thereby, it is possible to generate a bias magnetic field composed of a series of uniform and substantially circular magnetic fluxes with respect to the substrate 33.

  On the other hand, in FIG. 4B, the first magnetic field applying means 41 and the second magnetic field applying means 42 are arranged on the different planes along one surface of the substrate 43 having a step. Thereby, a bias magnetic field composed of an elliptical magnetic flux deflected with respect to the substrate 43 can be generated. In FIG. 4C, the first magnetic field applying means 51 and the second magnetic field applying means 52 are constituted by spiral coils having different numbers of turns. Thereby, it is possible to generate a bias magnetic field including a magnetic flux whose magnetic flux density has changed.

  The two magnetic field applying units may be formed on different substrates and not electrically connected. In FIG. 5A, a first magnetic field applying unit 63 made of a spiral coil is arranged on the first substrate 61, and a second magnetic field applying unit 64 made of a spiral coil is arranged on the second substrate 62, respectively. Thereby, the 1st board | substrate 61 and the 2nd board | substrate 62 can be manufactured separately and can be combined, and manufacture becomes easy. Further, the flow of the magnetic flux forming the bias magnetic field to be generated can be adjusted by freely adjusting the interval between the first magnetic field applying means 63 and the second magnetic field applying means 64.

  In FIG. 5B, a first magnetic field applying means 73 and a second magnetic field applying means 74 each comprising a spiral coil are arranged on the first substrate 71 and the second substrate 72, respectively. By shifting the second substrate 72 from each other, the first magnetic field applying means 73 and the second magnetic field applying means 74 are arranged on different surfaces. Thereby, the first magnetic field applying means 73 and the second magnetic field applying means 74 can be laid out freely with respect to each other, and the degree of freedom in designing the magnetic device is increased.

It is the perspective view and sectional drawing which show an example of the magnetic device of this invention. It is a perspective view which shows another example of the magnetic device of this invention. It is sectional drawing in the AA of the magnetic device shown in FIG. It is a perspective view which shows another example of the magnetic device of this invention. It is a perspective view which shows another example of the magnetic device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Magnetic device, 11 1st magnetic field application means, 12 2nd magnetic field application means, 13 Magnetic sensor, 21a, 22a Spiral coil, 25a, 25b Magnetic body.

Claims (4)

A magnetic device comprising at least a first magnetic field applying means, a second magnetic field applying means, and a magnetic sensor,
The first magnetic field applying unit and the second magnetic field applying unit form one annular bias magnetic field, and the magnetic sensor is arranged so that a magnetic sensitive direction thereof is along a direction of the bias magnetic field. And magnetic device.   The magnetic device according to claim 1, wherein the magnetic sensing direction of the magnetic sensor is arranged in an annular central region of the bias magnetic field.   2. The magnetic device according to claim 1, wherein a magnetic material is further arranged so as to overlap a part of the first magnetic field applying unit and the second magnetic field applying unit. The magnetic device according to claim 1, wherein the first magnetic field applying unit and the second magnetic field applying unit are spiral coils having a planar shape.

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