JP2008020239A - Magnetic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a miniaturizable magnetic device having excellent reliability, capable of lowering cost easily. <P>SOLUTION: This magnetic device 10 is equipped with the first base material 11 comprising a magnetic body, a magnetic field detection means 12 and a magnetic field application means 13 arranged to sandwich the first base material 11. The first base material 11 is constituted of an elastic body expandable/contractible by a pressure change, and for example, the magnetic field detection means 12 is arranged on one surface 11a side thereof, and the magnetic field application means 13 is arranged on the other surface 11b side thereof. The magnetic field detection means 12 is preferably a magnetic element wherein a resistance value or the like is changed by fluctuation of the magnetic field. The magnetic field application means 13 applied the magnetic field to the magnetic field detection means 12 through the first base material 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a magnetic device including a magnetic sensor, and more particularly to a magnetic device applicable as a pressure sensor.

  Conventionally, a mechanical pressure sensor using a Bourdon tube is known as a device for detecting pressure. Such a mechanical pressure sensor has a problem that its configuration is complicated and large. Therefore, electronic pressure sensors are becoming mainstream in recent years instead of mechanical pressure sensors.

Examples of the electronic pressure sensor include a sensor that detects a change in pressure by forming a diaphragm that is curved by pressure on a semiconductor substrate or the like, and detecting the curvature of the diaphragm. Such an electronic pressure sensor can be formed using a semiconductor microfabrication technique, has few mechanical moving parts, and can be easily downsized. For example, Patent Document 1 describes a pressure sensor configured to form a space partitioned on one side and the other side of a metal diaphragm, and to detect the curvature of the diaphragm due to pressure fluctuation by a Hall element. Yes.
JP-A-7-92047

  However, in order to obtain a diaphragm having a uniform thickness, the conventional electronic pressure sensor as described above is manufactured by accurately aligning both sides of a semiconductor substrate and performing anisotropic etching to form a diaphragm. There was a problem of cost. Moreover, the diaphragm which thinned such a semiconductor substrate was easy to be damaged by excessive pressure, and there existed a subject also in the surface of intensity | strength and durability. Furthermore, there is a problem that the configuration is complicated and expensive, such as a compensation circuit for correcting variations in output voltage with respect to pressure and correction due to temperature fluctuations.

  The present invention has been made in view of the above circumstances, and by providing a magnetic device having a structure excellent in mechanical durability and having a simple structure and high reliability by eliminating a diaphragm. Objective.

The magnetic device according to claim 1 of the present invention includes at least a first base material made of an elastic body, a magnetic field detection means and a magnetic field application means arranged so as to sandwich the first base material. And
A magnetic device according to a second aspect of the present invention is the magnetic device according to the first aspect, characterized in that a second base material made of a rigid body is disposed on the magnetic field detection means side of the first base material.
A magnetic device according to a third aspect of the present invention is characterized in that, in the first or second aspect, a third base material made of a rigid body is disposed on the magnetic field application means side of the first base material.
A magnetic device according to a fourth aspect of the present invention is the magnetic device according to the second aspect, wherein the magnetic field detection means is arranged inside the first base material and / or the second base material.
A magnetic device according to a fifth aspect of the present invention is the magnetic device according to the third aspect, wherein the magnetic field applying means is arranged inside the first base material and / or the third base material.
A magnetic device according to a sixth aspect of the present invention is the magnetic device according to the first aspect, wherein the first base material includes an internal space.

  According to the magnetic device of the present invention, by arranging the magnetic field detection means and the magnetic field application means so as to sandwich the first base material, when the first base material, which is an elastic body, is compressed by pressure, the magnetic field detection means The magnetic field strength applied from the magnetic field applying means to the magnetic field detecting means changes. By detecting the change in the resistance value of the magnetic field detection means due to the change in the magnetic field strength, the change in the pressure applied to the first base material can be reliably detected.

  Since such a magnetic device can be manufactured simply by providing a magnetic field detecting means and a magnetic field applying means on the first base material that is an elastic body, the manufacturing cost can be reduced. In addition, by eliminating the need for a diaphragm, the mechanical durability is excellent. Furthermore, by eliminating the need for a compensation circuit, it is possible to provide a magnetic device that can be applied as a pressure sensor with a simple structure and high reliability.

  Hereinafter, an embodiment in which a magnetic device according to the present invention is used as a pressure sensor will be described with reference to the drawings. The present invention is not limited to such an embodiment.

  Fig.1 (a) is sectional drawing which shows an example of the magnetic device (pressure sensor) of this invention. The magnetic device 10 of the present invention includes a first base material 11 made of an elastic body, and a magnetic field detection means 12 and a magnetic field application means 13 arranged so as to sandwich the first base material 11. The first base material 11 is composed of an elastic body that can be expanded and contracted by a change in pressure. For example, the magnetic field detecting means 12 is disposed on the one surface 11a side, and the magnetic field applying means 13 is disposed on the other surface 11b side.

  The magnetic field detection means 12 may be a magnetic element whose resistance value changes due to fluctuations in the magnetic field. The magnetic field application unit 13 applies a magnetic field to the magnetic field detection unit 12 via the first base material 11.

  According to the magnetic device (pressure sensor) having such a configuration, for example, when pressure is applied to the one surface 11a of the first base material 11 with respect to the magnetic device 10 in the state illustrated in FIG. ), The first base material 11 made of an elastic body is compressed by the pressure P, and the interval T between the magnetic field applying means 13 and the magnetic field detecting means 12 is narrowed.

  As shown in FIG. 2A, if the magnetic field having the magnetic field intensity M1 is applied from the magnetic field applying unit 13 to the magnetic field detecting unit 12 before the first base material 11 is compressed, pressure is applied. When the first base material 11 is compressed and the magnetic field application means 13 approaches the magnetic field detection means 12, the magnetic field intensity M2 applied from the magnetic field application means 13 to the magnetic field detection means 12 as shown in FIG. It becomes larger than the magnetic field strength M1 before the pressure is applied.

  At this time, if a constant sense current A is allowed to flow through the magnetic field detection means 12, if the magnetic field strength increases due to the change (approach) of the interval T between the magnetic field application means 13 and the magnetic field detection means 12, the magnetic field detection means 12 The resistance value R changes. By detecting the change in the resistance value R of the magnetic field detection means 12 as the change in the sense current A, it is possible to detect that the first base material 11 has been compressed, that is, the pressure applied to the first base material 11. it can.

  As described above, according to the magnetic device 10 of the present invention, the first base material 11 that is an elastic body is pressurized by arranging the magnetic field detection means 12 and the magnetic field application means 13 so as to sandwich the first base material 11. The distance between the magnetic field detection means 12 and the magnetic field application means 13 approaches, and the strength of the magnetic field applied from the magnetic field application means 13 to the magnetic field detection means 12 changes. By detecting the change in the resistance value of the magnetic field detection means 12 due to the change in the magnetic field intensity, it is possible to reliably detect the change in the pressure applied to the first substrate 11.

  Since the magnetic device 10 has a simple configuration in which the magnetic field detection means 12 and the magnetic field application means 13 are arranged on the one surface side and the other surface side of the first base material 11 that is an elastic body, the pressure is detected at a low cost. A sensor can be configured. Moreover, since there are few mechanical movable parts, the magnetic device 10 which can be applied as a highly reliable pressure sensor with less occurrence of problems can be provided.

  The 1st base material 11 should just be comprised from porous bodies, such as an elastic body, for example, sponge, rubber | gum. In particular, by using an elastic body excellent in heat resistance, cold resistance, and water repellency such as silicon rubber for the first base material 11, pressure can be reliably detected under various environments such as a high temperature environment and an outdoor environment. it can.

  The magnetic field applying unit 13 may be any unit as long as it can stably generate a magnetic field with a constant intensity and apply a magnetic field toward the magnetic field detecting unit 12. The magnetic field applying unit 13 may be constituted by, for example, an electromagnet such as a coil, a permanent magnet, or the like. In particular, by using a permanent magnet, a stable and constant magnetic field can be formed at low cost without using an external power source or the like.

  The magnetic field detection unit 12 may be any device as long as it can detect an intensity change of an external magnetic field (a magnetic field applied by the magnetic field application unit). For example, a magnetic effect (MR) element is preferable. Used for. Such a magnetic effect (MR) element can be manufactured at a low cost by a semiconductor process or the like, and can detect a change in a magnetic field with high accuracy.

  When a magnetic effect (MR) element is used as the magnetic field detection means 12, the magnetization direction B of the magnetic field detection means 12 is, for example, in a state where no pressure is applied to the first base material 11 as shown in FIG. , Along the vertical direction L. Then, as shown in FIG. 2B, when pressure is applied to the first base material 11 to compress the first base material 11, and the magnetic field application means 13 approaches the magnetic field detection means 12, the magnetic field detection means 12. The magnetization direction B of the magnetic field detection means 12 is tilted with respect to the vertical direction L due to the increase of the magnetic field applied to. Since the magnetic field detection means 12 changes the resistance value R almost quantitatively in accordance with the inclination θ of the magnetization direction B, the pressure applied to the first substrate 11 by measuring the resistance value R of the magnetic field detection means 12. The value can be detected.

  When a magnetic effect (MR) element is used as the magnetic field detection means 12, the first base material 11 is contracted (compressed) step by step as shown in FIG. The thickness T of the base material 11 and the resistance value R of the magnetic field detection means 12 are measured. An example in which the relationship between the thickness T of the first base material 11 and the resistance value R of the magnetic field detection means 12 is plotted is the graph shown in FIG.

  From such a graph, a function of the amount of shrinkage of the first base material 11 of a certain material and the resistance value R of the magnetic field detection means 12 can be obtained. Since the amount of contraction due to the pressure of the elastic body is considered to be the same if it is of the same material and the same size, if the amount of contraction due to the pressure of the elastic body is known, the resistance value R of the magnetic field detection means 12 By applying the function, the pressure value applied to the first base material 11 can be easily obtained.

  FIG. 5 is a perspective view showing another embodiment of the magnetic device of the present invention. In FIG. 5, the first base material is shown in a transmissive state. In the magnetic device 20 in this embodiment, the magnetic field applying means 23 and the third base material 26 are arranged on the one surface 21a side of the first base material 21 made of an elastic body. Further, the magnetic field detection means 22 and the second base material 25 are arranged on the other surface 21 b side of the first base material 21. The 2nd base material 25 and the 3rd base material 26 consist of a rigid body, and should just be a hard resin, a metal board | substrate, etc., for example.

  By providing the second base material 25 and the third base material 26 in contact with the first base material 21, the pressure applied to the first base material 21 can be received more accurately. Further, the range in which the pressure is received and measured can be arbitrarily set by changing the size of the second base material 25 or the third base material 26. Furthermore, the intensity | strength and durability of the magnetic device 20 whole can be improved by covering the 1st base material 21 with the 2nd base material 25 and the 3rd base material 26 which consist of a rigid body.

  In this embodiment, as the magnetic field detection means 22, a magnetoresistive element in which a conductor 22b having a meander shape is formed on an insulating substrate 22a is used. A magnetoresistive element having such a meander-shaped conductor 22b can be manufactured at a low cost and can reliably detect a change in the magnetic field.

  Hereinafter, preferable configuration examples of the magnetic device of the present invention will be listed. In the magnetic device 30 shown in FIG. 6, the third base material 32 is disposed on the one surface 31 a side of the first base material 31 made of an elastic body, and the magnetic field applying means 33 is disposed inside the third base material 32. . A second base material 34 is disposed on the other surface 31 b side of the first base material 31, and a magnetic field detection means 35 is disposed inside the second base material 34.

  In the magnetic device 40 shown in FIG. 7, the third base material 42 is disposed on the one surface 41 a side of the first base material 41 made of an elastic body, and the magnetic field applying means 43 is disposed inside the third base material 42. . Further, the second base material 44 is disposed on the other surface 41b side of the first base material 41, and the magnetic field detection means 45 is disposed in the first base material 41 near the other surface 41b of the first base material 41. ing.

  In the magnetic device 50 shown in FIG. 8, the third base material 52 is disposed on the one surface 51 a side of the first base material 51 made of an elastic body, and the first base material 51 near the one surface 51 a of the first base material 51. Magnetic field applying means 53 is arranged inside. A second base material 54 is disposed on the other surface 51 b side of the first base material 51, and magnetic field detection means 55 is disposed inside the second base material 54.

  In the magnetic device 60 shown in FIG. 9, the third base material 62 is disposed on the one surface 61 a side of the first base material 61 made of an elastic body, and the first base material 61 is close to the one surface 61 a of the first base material 61. Magnetic field applying means 63 is arranged inside. A second base 64 is disposed on the other surface 61b side of the first base 61, and a magnetic field detection means 65 is disposed in the first base 61 near the other surface 61b of the first base 61. ing.

  In the magnetic device 70 shown in FIG. 10, a third base material 72 is arranged on the one surface 71 a side of the first base material 71 made of an elastic body, and a magnetic field applying means 73 is arranged inside the third base material 72. . Further, a magnetic field detecting means 75 is disposed inside the first base material 71 near the other surface 71 b of the first base material 71.

  In the magnetic device 80 shown in FIG. 11, a magnetic field applying unit 83 is disposed inside the first base material 81 near the one surface 81 a of the first base material 81 made of an elastic body. The second base 84 is disposed on the other surface 81 b side of the first base 81, and the magnetic field detection means 85 is disposed inside the second base 84.

  In the magnetic device 90 shown in FIG. 12, magnetic field applying means 93 is disposed inside the first base material 91 near the one surface 91 a made of an elastic body. Further, a magnetic field detecting means 95 is arranged inside the first base material 91 near the other surface 91b of the first base material 91.

  In the magnetic device 100 shown in FIG. 13, a plurality of magnetic field applying means 103 a and 103 b are arranged inside the first base material 101 near the one surface 101 a made of an elastic body. In addition, magnetic field detection means 105 is arranged inside the first base material 101 near the other surface 101 b of the first base material 101. By providing a plurality of magnetic field applying means 103a and 103b, a strong magnetic field can be stably applied by the magnetic field detecting means 105.

  In the magnetic device 110 shown in FIG. 14, a third substrate 112 is disposed on the one surface 111 a side of the first substrate 111 made of an elastic body, and a magnetic field applying unit 113 is disposed inside the third substrate 112. . A second base material 114 is disposed on the other surface 111 b side of the first base material 111, and a magnetic field detection means 115 is disposed inside the second base material 114. And the 1st base material 111 is provided with internal space 111a. By forming the internal space 111a in the first base material 111, the magnetic device 110 can be reduced in weight. In addition, if the internal space 111a is an airtight space, the amount of contraction of the first base material 111 due to the external pressure can be freely adjusted by adjusting the pressure of the enclosed gas.

  In the magnetic device 120 shown in FIG. 15, the third base material 122 is disposed on the one surface 121 a side of the first base material 121 made of an elastic body, and straddles the inside of the third base material 122 and the inside of the first base material 121. In this way, magnetic field applying means 123 is arranged. A second base material 124 is disposed on the other surface 121b side of the first base material 121, and a magnetic field detection means 125 is disposed so as to straddle the inside of the second base material 124 and the inside of the second base material 124. Yes.

It is sectional drawing which shows an example of the magnetic device of this invention. It is explanatory drawing which shows the effect | action of the magnetic device of this invention. It is explanatory drawing which shows the example of a measurement of the relationship between the thickness of a 1st base material, and the resistance value of a magnetic field detection means. It is the graph which showed the relationship between the thickness of a 1st base material, and the resistance value of a magnetic field detection means. It is a disassembled perspective view which shows another example of the magnetic device of this invention. It is sectional drawing which shows another example of the magnetic device of this invention. It is sectional drawing which shows another example of the magnetic device of this invention. It is sectional drawing which shows another example of the magnetic device of this invention. It is sectional drawing which shows another example of the magnetic device of this invention. It is sectional drawing which shows another example of the magnetic device of this invention. It is sectional drawing which shows another example of the magnetic device of this invention. It is sectional drawing which shows another example of the magnetic device of this invention. It is sectional drawing which shows another example of the magnetic device of this invention. It is sectional drawing which shows another example of the magnetic device of this invention. It is sectional drawing which shows another example of the magnetic device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Magnetic device (pressure sensor), 11 1st base material, 12 Magnetic field detection means, 13 Magnetic field application means.

Claims (6)

  A magnetic device comprising at least a first base material made of an elastic body, a magnetic field detection means and a magnetic field application means arranged so as to sandwich the first base material.   The magnetic device according to claim 1, wherein the second base material made of a rigid body is disposed on the magnetic field detection means side of the first base material.   The magnetic device according to claim 1, wherein a third base material made of a rigid body is disposed on the magnetic field applying means side of the first base material.   The magnetic device according to claim 2, wherein the magnetic field detection means is disposed inside the first base material and / or the second base material.   The magnetic device according to claim 3, wherein the magnetic field applying unit is disposed inside the first base material and / or the third base material. The magnetic device according to claim 1, wherein the first substrate has an internal space.

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