JPH0534425A - Magnetic field focusing machine - Google Patents
Magnetic field focusing machineInfo
- Publication number
- JPH0534425A JPH0534425A JP18775491A JP18775491A JPH0534425A JP H0534425 A JPH0534425 A JP H0534425A JP 18775491 A JP18775491 A JP 18775491A JP 18775491 A JP18775491 A JP 18775491A JP H0534425 A JPH0534425 A JP H0534425A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic field
- per unit
- unit length
- plates
- center portion
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Measuring Magnetic Variables (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は高感度磁場検出器の性能
を向上する磁場集束器に関するものである。FIELD OF THE INVENTION The present invention relates to a magnetic field concentrator for improving the performance of a high-sensitivity magnetic field detector.
【０００２】[0002]
【従来の技術】従来用いられてきた磁場検出装置は被測
定磁場に対する影響の観点から大きく以下の２つに分類
される。第１のタイプは磁性体等を用い測定対象の磁場
の道筋（磁路）を変化させ磁場検出素子に磁束を導く構
成のものであり、第２のタイプは磁路を変化させず測定
磁場に対し直接検出素子を挿入する構成のものである。
磁路を任意に変える方式の代表例は磁気ヘッドである。
磁気ヘッドは記録媒体から発生する磁場を軟磁性体のコ
アを用いてコイルまで導き、磁気誘導によってコイルに
発生する電圧として磁場を検出している。即ち、磁路を
変化させる構造の磁場検出器は被測定磁場が空間的に不
均一な場合に用いられる。一方、磁路を変化させない磁
場検出器はホール素子、フラックスゲート形磁束計、ス
クィッド磁束計等が主な例である。これらの磁場測定器
は測定する磁場が元来小さく、また、均一であることが
特徴である。被測定磁場が小さいので軟磁性体のコアを
用いて磁場を任意の方向に集束しようとしても、コアに
不可避的に含まれる不可逆な磁化過程のために被測定磁
場に比例した応答が得られない。例えば、軟磁性体であ
るパーマロイ合金等でも形状によっては０．１ Ｏｅ程
度の保磁力があり、被測定磁場がこの値以下では磁場を
集束させる効果は安定して得られない。従って、第２の
タイプの磁場検出装置には磁路を作為的に変更するよう
な構成は適用されていなかった。2. Description of the Related Art Conventionally used magnetic field detection devices are roughly classified into the following two types from the viewpoint of influence on a magnetic field to be measured. The first type uses a magnetic material or the like to change the path (magnetic path) of the magnetic field to be measured and guide the magnetic flux to the magnetic field detection element, while the second type changes the magnetic field without changing the magnetic path. On the other hand, the detection element is directly inserted.
A typical example of a method of arbitrarily changing the magnetic path is a magnetic head.
A magnetic head guides a magnetic field generated from a recording medium to a coil by using a soft magnetic core, and detects the magnetic field as a voltage generated in the coil by magnetic induction. That is, the magnetic field detector having a structure that changes the magnetic path is used when the magnetic field to be measured is spatially non-uniform. On the other hand, Hall elements, fluxgate type magnetometers, squid magnetometers, etc. are the main examples of magnetic field detectors that do not change the magnetic path. These magnetic field measuring devices are characterized in that the magnetic field to be measured is originally small and uniform. Since the magnetic field to be measured is small, even if you try to focus the magnetic field in any direction using a soft magnetic core, a response proportional to the magnetic field to be measured cannot be obtained due to the irreversible magnetization process inevitably included in the core. . For example, even a soft magnetic material such as permalloy alloy has a coercive force of about 0.1 Oe depending on the shape, and if the measured magnetic field is less than this value, the effect of focusing the magnetic field cannot be stably obtained. Therefore, the structure for artificially changing the magnetic path has not been applied to the second type magnetic field detection device.
【０００３】[0003]
【発明が解決しようとする課題】本発明は上記の事情に
鑑みてなされたもので、微弱な磁場の検出に際して、磁
場を集束して感度を高める磁場集束器を提供することを
目的する。SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a magnetic field concentrator that focuses a magnetic field to enhance sensitivity when a weak magnetic field is detected.
【０００４】[0004]
【課題を解決するための手段】本発明は上記課題を解決
するために、反磁性体で形成された２枚の板が向かい合
った構造で、外周部の単位長さ当りの開口面積が中央部
の単位長さ当りの開口面積より大きくなるように中央部
の間隔が外周部よりも狭くなっていることを特徴とする
ものである。In order to solve the above-mentioned problems, the present invention has a structure in which two plates made of a diamagnetic material face each other, and the opening area per unit length of the outer peripheral portion is the central portion. The distance between the central portions is smaller than that of the outer peripheral portion so as to be larger than the opening area per unit length.
【０００５】[0005]
【作用】上記手段により、微弱な磁場の検出に際して、
中央の面間隔が狭まった部分に磁場を集束して感度を高
めるようにしたものである。By the above means, when detecting a weak magnetic field,
This is to enhance the sensitivity by focusing the magnetic field on the part where the surface spacing in the center is narrow.
【０００６】[0006]
【実施例】以下図面を参照して本発明の実施例を詳細に
説明する。Embodiments of the present invention will now be described in detail with reference to the drawings.
【０００７】本発明は上記の第２のタイプの磁場検出装
置において、被測定磁場を空間的に集束し磁場を強めて
から検出素子に導き、実効的な検出感度を向上させる。
磁場を集束させるために、図１に示すような超伝導材料
で作製した２枚の板１，２を互いに対向した構造で、外
周部の単位長さ当りの開口面積が中央部の単位長さ当り
の開口面積より大きくなるように中央部の間隔が外周部
よりも狭くなっている磁場集束器３を用いる。超伝導状
態にある物質は磁場を物質の外に押し出す効果（マイス
ナー効果）を示す。従って、図１に示す磁場集束器３に
対してＺ方向の磁場が印加されると、中央の面間隔が狭
まった部分に磁場が集中する。被測定磁場は入り口の単
位長さ当りの開口面積（Ｓ１）と間隔が狭まった部分の
単位長さ当りの開口面積（Ｓ２）の比（Ｓ１／Ｓ２）だ
け強化される。板１，２の間隔が狭まった部分にホール
素子、フラックスゲート形磁束計、スクィッド磁束計等
の磁場検出器を配置すれば、磁場検出感度がＳ１／Ｓ２
倍だけ増大する。以上の効果の本質は超伝導状態では完
全反磁性現象が起こることを利用しており、超伝導状態
を壊してしまう様な強い外部磁場（臨界磁場：Ｈｃｌ）
が印加されればこの効果は期待できない。一般に、臨界
磁場Ｈｃｌは小さくても十Ｏｅ以上はあるので、被測定
磁場がミリＯｅのオーダーの場合に、その磁場を数桁強
めたとしても十分使用できる。従って、本発明の磁場集
束器３は微弱磁場を対象としたものと言える。また、Ｘ
方向からの磁場は本磁場集束器３によって遮蔽されるの
でノイズを低減する効果も期待できる。以下具体的な実
施例を挙げて説明する。According to the second aspect of the magnetic field detecting device of the present invention, the magnetic field to be measured is spatially focused and the magnetic field is strengthened before being guided to the detection element to improve the effective detection sensitivity.
In order to focus the magnetic field, two plates 1 and 2 made of a superconducting material as shown in FIG. 1 are opposed to each other, and the opening area per unit length of the outer peripheral portion is the unit length of the central portion. The magnetic field concentrator 3 is used in which the interval in the central part is narrower than that in the outer peripheral part so as to be larger than the opening area per hit. A substance in the superconducting state exhibits an effect of pushing a magnetic field out of the substance (Meissner effect). Therefore, when a magnetic field in the Z direction is applied to the magnetic field concentrator 3 shown in FIG. 1, the magnetic field concentrates on the portion where the center surface spacing is narrowed. The magnetic field to be measured is strengthened by the ratio (S1 / S2) of the opening area per unit length (S1) of the entrance to the opening area per unit length (S2) of the narrowed portion. If a magnetic field detector such as a Hall element, a fluxgate type magnetometer, or a squid magnetometer is arranged in a portion where the distance between the plates 1 and 2 is narrow, the magnetic field detection sensitivity is S1 / S2.
Increase by a factor of two. The essence of the above effect is that the phenomenon of complete diamagnetism occurs in the superconducting state, and a strong external magnetic field (critical magnetic field: Hcl) that destroys the superconducting state is used.
If this is applied, this effect cannot be expected. In general, the critical magnetic field Hcl is 10 Oe or more even if it is small, so that when the magnetic field to be measured is on the order of milliOe, it can be sufficiently used even if the magnetic field is increased by several digits. Therefore, it can be said that the magnetic field concentrator 3 of the present invention is intended for a weak magnetic field. Also, X
Since the magnetic field from the direction is shielded by the magnetic field concentrator 3, an effect of reducing noise can be expected. Specific examples will be described below.
【０００８】図２に本発明の具体的実施例の構成図を示
す。３は図１に説明したものと同様の磁場集束器であ
る。磁場集束器３を構成する板１の上辺（ａ−ａ′）の
中央部１ｃｍ当りの開口面積Ｓ１は４ｃｍ2 、板１，２
の間隔が狭まった部分である板１の辺（ｂ−ｂ′）の中
央部の１ｃｍ当りの開口面積Ｓ２は２ｃｍ2 である。板
１，２はY-Ba-Cu 系酸化物超伝導材料で形成されてい
る。この材料の超伝導転移温度は９１Ｋであり、液体窒
素温度における臨界磁場（Ｈｃｌ）は１２ Ｏｅであ
る。４は磁場検出素子である。具体的にはホール素子を
用いた磁束計である。５は冷却装置である。６は被測定
磁場発生用コイルである。７は磁場発生用電源である。
図２と同一の構造で磁場集束器３を省いた構成でも外部
磁場の検出は可能なので、磁場集束器３の効果を確認す
るためには両者を比較することが必要である。FIG. 2 shows a block diagram of a concrete embodiment of the present invention. 3 is a magnetic field concentrator similar to that described in FIG. The opening area S1 per 1 cm of the central portion of the upper side (aa ') of the magnetic field concentrator 3 is 4 cm 2 , and the plates 1 and 2 are
The opening area S2 per 1 cm of the central portion of the side (bb ') of the plate 1 which is the portion where the distance between the two is narrowed is 2 cm 2 . The plates 1 and 2 are made of a Y-Ba-Cu-based oxide superconducting material. The superconducting transition temperature of this material is 91 K and the critical magnetic field (Hcl) at liquid nitrogen temperature is 12 Oe. 4 is a magnetic field detection element. Specifically, it is a magnetometer using a Hall element. 5 is a cooling device. Reference numeral 6 is a coil for generating a magnetic field to be measured. Reference numeral 7 is a magnetic field generating power source.
Since the external magnetic field can be detected even with the structure having the same structure as in FIG. 2 and omitting the magnetic field concentrator 3, it is necessary to compare the two in order to confirm the effect of the magnetic field concentrator 3.
【０００９】図３は規格化出力（磁場集束器３を用いた
場合と用いない場合の出力の比）の外部磁場依存性を示
す。外部磁場（被測定磁場）が１ Ｏｅ以下では規格化
出力はほぼ２とＳ１／Ｓ２に等しく、磁場集束器３の効
果が確認された。外部磁場が１ Ｏｅ以上で規格化出力
が減少する理由は、超伝導体の結晶粒界等が臨界磁場Ｈ
ｃｌが低いため磁気シールド効果が低下したものと考え
られる。FIG. 3 shows the external magnetic field dependence of the normalized output (the ratio of the output with and without the magnetic field concentrator 3). When the external magnetic field (measured magnetic field) is 1 Oe or less, the normalized output is approximately 2, which is equal to S1 / S2, and the effect of the magnetic field concentrator 3 was confirmed. The reason why the normalized output decreases when the external magnetic field is 1 Oe or more is that the crystal grain boundaries of the superconductor have a critical magnetic field H
It is considered that the magnetic shield effect was lowered because cl was low.
【００１０】尚、磁場集束器はホール素子のみではなく
在来の磁場センサーの高感度化にも有効である。The magnetic field concentrator is effective not only for Hall elements but also for increasing the sensitivity of conventional magnetic field sensors.
【００１１】[0011]
【発明の効果】以上述べたように本発明によれば、中央
の面間隔が狭まった部分に磁場を集束して感度を高める
ことにより、被測定磁場を空間的に集束し磁場を強めて
から検出素子に導き、実効的な検出感度を向上させるこ
とができる。As described above, according to the present invention, the magnetic field to be measured is spatially focused and the magnetic field is strengthened by focusing the magnetic field on the portion where the surface spacing in the center is narrowed to enhance the sensitivity. It is possible to improve the effective detection sensitivity by leading to the detection element.
【図１】本発明磁場集束器の一実施例を示す斜視図であ
る。FIG. 1 is a perspective view showing an embodiment of a magnetic field concentrator of the present invention.
【図２】本発明に係る磁場検出器の一例を示す構成図で
ある。FIG. 2 is a configuration diagram showing an example of a magnetic field detector according to the present invention.
【図３】本発明に係る規格化出力（磁場集束器を用いた
場合と用いない場合の出力の比）の外部磁場依存性の一
例を示す特性図である。FIG. 3 is a characteristic diagram showing an example of an external magnetic field dependency of a normalized output (ratio of output with and without a magnetic field concentrator) according to the present invention.
３…磁場集束器、４…磁場検出素子、５…冷却装置、６
…被測定磁場発生用コイル、７…磁場発生用電源。3 ... Magnetic field concentrator, 4 ... Magnetic field detection element, 5 ... Cooling device, 6
... measured magnetic field generating coil, 7 ... magnetic field generating power supply.
Claims (2)
合った構造で、外周部の単位長さ当りの開口面積が中央
部の単位長さ当りの開口面積より大きくなるように中央
部の間隔が外周部よりも狭くなっていることを特徴とす
る磁場集束器。1. A structure in which two plates made of a diamagnetic material are opposed to each other, and a central portion is formed so that an opening area per unit length of an outer peripheral portion is larger than an opening area per unit length of a central portion. The magnetic field concentrator is characterized in that the distance between the two is narrower than that of the outer peripheral portion.
特徴とする請求項１記載の磁場集束器。2. The magnetic field concentrator according to claim 1, wherein a superconductor is used as the diamagnetic substance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18775491A JPH0534425A (en) | 1991-07-26 | 1991-07-26 | Magnetic field focusing machine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18775491A JPH0534425A (en) | 1991-07-26 | 1991-07-26 | Magnetic field focusing machine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0534425A true JPH0534425A (en) | 1993-02-09 |
Family
ID=16211619
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP18775491A Pending JPH0534425A (en) | 1991-07-26 | 1991-07-26 | Magnetic field focusing machine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0534425A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001188003A (en) * | 1999-06-28 | 2001-07-10 | Denso Corp | Rotational angle detecting device |
-
1991
- 1991-07-26 JP JP18775491A patent/JPH0534425A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001188003A (en) * | 1999-06-28 | 2001-07-10 | Denso Corp | Rotational angle detecting device |
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