JPH05341026A - Magnetic sensor - Google Patents
Magnetic sensorInfo
- Publication number
- JPH05341026A JPH05341026A JP4150590A JP15059092A JPH05341026A JP H05341026 A JPH05341026 A JP H05341026A JP 4150590 A JP4150590 A JP 4150590A JP 15059092 A JP15059092 A JP 15059092A JP H05341026 A JPH05341026 A JP H05341026A
- Authority
- JP
- Japan
- Prior art keywords
- magnet
- bias
- magnetic field
- magnetic
- magnetic sensor
- 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.)
- Withdrawn
Links
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- Measuring Magnetic Variables (AREA)
- Hall/Mr Elements (AREA)
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
- Transmission And Conversion Of Sensor Element Output (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は磁気センサに関する。詳
しくは、磁気抵抗パターンでブリッジ回路を構成した磁
気抵抗素子の、バイアス磁界印加用磁石に等方性磁石を
用いてバイアス磁界方向のずれによる不平衡電圧の発生
を防止した磁気センサに関する。FIELD OF THE INVENTION The present invention relates to magnetic sensors. More specifically, the present invention relates to a magnetic sensor that uses an isotropic magnet for a bias magnetic field applying magnet of a magnetoresistive element that forms a bridge circuit with a magnetoresistive pattern to prevent generation of an unbalanced voltage due to a shift in the bias magnetic field direction.
【０００２】強磁性薄膜を用いた磁気抵抗素子は、ホー
ル素子、半導体型磁気抵抗素子に比べ、微小磁界に対す
る感度が高く、分解能に優れるため、位置センサ、角度
センサ、電流センサ、ロータリーエンコーダ等に利用さ
れている。また磁気抵抗素子の出力を図３に示すように
外部磁界に対してリニアなものにすると、さらに高性能
なセンサとしての用途が期待できる。図３のような出力
特性を持つ磁気抵抗素子で重要なことは、測定磁界範囲
における出力特性の直線性、および正負の磁界に対する
出力の対称性である。近年、センサデバイスも小型化、
高性能化が望まれ、簡易な構成で精度良く安定に動作す
る磁気センサの実現が望まれている。A magnetoresistive element using a ferromagnetic thin film has a higher sensitivity to a minute magnetic field and an excellent resolution as compared with a Hall element or a semiconductor type magnetoresistive element, so that it is used in a position sensor, an angle sensor, a current sensor, a rotary encoder and the like. It's being used. If the output of the magnetoresistive element is made linear with respect to the external magnetic field as shown in FIG. 3, it can be expected to be used as a sensor with higher performance. What is important in the magnetoresistive element having the output characteristic as shown in FIG. 3 is the linearity of the output characteristic in the measurement magnetic field range and the symmetry of the output with respect to the positive and negative magnetic fields. In recent years, sensor devices have become smaller,
Higher performance is desired, and it is desired to realize a magnetic sensor that has a simple structure and operates stably with high accuracy.
【０００３】[0003]
【従来の技術】磁気抵抗素子の出力を図３のようにリニ
アなものにするには、磁気抵抗パターンでブリッジ回路
を構成し、それにバイアス磁界を印加するのが有効であ
る。従来の磁気抵抗素子にバイアス磁界を印加する方法
は、例えば図４に示すように、磁気抵抗素子１を形成し
たＳｉ基板２の裏面にバイアス磁界発生用の磁石３を貼
り付け、該磁石により磁気抵抗素子１にバイアス磁界を
印加するようにしている。2. Description of the Related Art In order to make the output of a magnetoresistive element linear as shown in FIG. 3, it is effective to construct a bridge circuit with a magnetoresistive pattern and apply a bias magnetic field to it. For example, as shown in FIG. 4, a conventional method of applying a bias magnetic field to a magnetoresistive element is to attach a bias magnetic field generating magnet 3 to the back surface of a Si substrate 2 on which the magnetoresistive element 1 is formed, and then use the magnet to generate a magnetic field. A bias magnetic field is applied to the resistance element 1.
【０００４】[0004]
【発明が解決しようとする課題】上記従来の磁気センサ
では、バイアス磁界印加用の磁石に異方性磁石を用いて
いた。そのため、Ｓｉ基板２に磁石３を貼り付けた後、
所定の方向に着磁しても、着磁の方向ではなく異方性の
向きに依存して磁界の向きが決まってしまう。異方性と
いうものは±５°くらいは傾いてしまうのが通常である
ので、その±５°のずれを磁気抵抗素子が読みとってし
まい、着磁後の不平衡電圧の変化となって表われる。そ
の結果、使用範囲を超えるのもが多くなり、歩留りが悪
くなる。図５にバイアス磁界のずれと検出出力の対称性
を示す。同図によれば磁石の発生磁界の角度ずれが１°
の場合、図３における検出磁界強度Ｈｓ／２における対
称性は１．５％と低下する。In the above conventional magnetic sensor, an anisotropic magnet is used as a magnet for applying a bias magnetic field. Therefore, after attaching the magnet 3 to the Si substrate 2,
Even if magnetized in a predetermined direction, the direction of the magnetic field is determined not by the direction of magnetization but by the direction of anisotropy. Since anisotropy is usually tilted by about ± 5 °, the magnetoresistive element reads the deviation of ± 5 °, which is represented as a change in the unbalanced voltage after magnetization. . As a result, the product often exceeds the range of use, resulting in poor yield. FIG. 5 shows the deviation of the bias magnetic field and the symmetry of the detection output. According to the figure, the angular deviation of the magnetic field generated by the magnet is 1 °
In this case, the symmetry at the detected magnetic field strength Hs / 2 in FIG. 3 decreases to 1.5%.
【０００５】本発明は、バイアス磁界発生用磁石からの
磁界方向と、磁気抵抗素子のバイアス磁界方向とを一致
させ不平衡電圧の発生を防止した磁気センサを実現しよ
うとする。The present invention intends to realize a magnetic sensor in which the direction of a magnetic field from a magnet for generating a bias magnetic field and the direction of a bias magnetic field of a magnetoresistive element are made to coincide with each other to prevent generation of an unbalanced voltage.
【０００６】[0006]
【課題を解決するための手段】本発明の磁気センサに於
いては、磁気抵抗パターンでブリッジ回路を構成した磁
気抵抗素子１２と、該磁気抵抗素子１２にバイアス磁界
を印加するバイアス磁石１１とを具備してなる磁気セン
サにおいて、上記バイアス磁石１１に等方性磁石を用
い、着磁の角度によって磁気抵抗素子１２に生ずる不平
衡電圧を調整することを特徴とする。In the magnetic sensor of the present invention, a magnetic resistance element 12 having a bridge circuit composed of a magnetic resistance pattern and a bias magnet 11 for applying a bias magnetic field to the magnetic resistance element 12 are provided. In the magnetic sensor provided, an isotropic magnet is used as the bias magnet 11, and the unbalanced voltage generated in the magnetoresistive element 12 is adjusted by the angle of magnetization.
【０００７】また、それに加えて、上記バイアス磁石１
１の形状を長方形にして形状異方性を付与したことを特
徴とする。また、それに加えて上記バイアス磁石１１の
形状を円形にして形状異方性を付与しないことを特徴と
する。この構成を採ることにより、不平衡電圧の発生を
防止した磁気センサが得られる。In addition to the above, the bias magnet 1 is also provided.
It is characterized in that the shape of No. 1 is made rectangular and shape anisotropy is given. In addition to that, the shape of the bias magnet 11 is circular so that shape anisotropy is not given. By adopting this configuration, it is possible to obtain a magnetic sensor that prevents the generation of an unbalanced voltage.
【０００８】[0008]
【作用】本発明では磁気センサのバイアス磁石１１に等
方性磁石を用いており、等方性磁石は着磁の向きによっ
て磁界の向きを変えられるため、磁気抵抗パターンのバ
イアス磁界方向にバイアス磁石の磁界方向を揃えること
ができる。これにより不平衡電圧の発生はなくなり、出
力の対称性は良好となる。In the present invention, an isotropic magnet is used as the bias magnet 11 of the magnetic sensor. Since the magnetic field of the isotropic magnet can be changed depending on the direction of magnetization, the bias magnet is in the bias magnetic field direction of the magnetoresistive pattern. The magnetic field directions can be aligned. As a result, no unbalanced voltage is generated and the output symmetry becomes good.
【０００９】[0009]
【実施例】図１は本発明の第１の実施例を示す斜視図で
ある。同図において、１０はＳｉ基板、１１はバイアス
磁石である。そして、Ｓｉ基板１０には、その上に強磁
性薄膜のジグザク形磁気抵抗パターンを４個ブリッジ接
続した磁気抵抗素子１２が形成されている。1 is a perspective view showing a first embodiment of the present invention. In the figure, 10 is a Si substrate and 11 is a bias magnet. Then, on the Si substrate 10, a magnetoresistive element 12 in which four zigzag magnetoresistive patterns of ferromagnetic thin films are bridge-connected is formed.
【００１０】また、バイアス磁石１１は等方性の磁石材
料で長方形の板状に形成され、Ｓｉ基板１０の下面に接
着されている。等方性磁石材料としては、等方性アルニ
コ、等方性鉄クロムコバルト、等方性バリウムフェライ
ト、等方性酸化物系ボンド磁石、等方性希土類コバルト
系ボンド磁石等がある。The bias magnet 11 is formed of an isotropic magnet material into a rectangular plate shape, and is bonded to the lower surface of the Si substrate 10. Examples of the isotropic magnet material include isotropic alnico, isotropic iron chromium cobalt, isotropic barium ferrite, isotropic oxide-based bonded magnet, and isotropic rare earth cobalt-based bonded magnet.
【００１１】このように構成された本実施例は、バイア
ス磁石１１に着磁してから磁気センサとして用いられる
が、その着磁は、磁石材料が等方性であるため、磁気抵
抗素子が必要とするバイアス磁界方向に正確に合わせる
ことができる。従って磁気抵抗素子パターンのブリッジ
回路には不平衡電圧が発生することはない。In this embodiment having the above-described structure, the bias magnet 11 is magnetized before it is used as a magnetic sensor. Since the magnet material is isotropic, the magnetoresistive element is required. The bias magnetic field direction can be accurately adjusted. Therefore, no unbalanced voltage is generated in the bridge circuit of the magnetoresistive element pattern.
【００１２】図２は本発明の第２の実施例を示す図であ
る。同図において、図１と同一部分は同一符号を付して
示した。本実施例は、基本的には第１の実施例と同様で
あり、異なるところは、第１の実施例ではバイアス磁石
１１が長方形の板状をなし、形状異方性を有していたの
に対し、本実施例では形状異方性が全くない円板状とし
たことである。FIG. 2 is a diagram showing a second embodiment of the present invention. In the figure, the same parts as those in FIG. 1 are designated by the same reference numerals. This embodiment is basically the same as the first embodiment, except that the bias magnet 11 in the first embodiment has a rectangular plate shape and has shape anisotropy. On the other hand, in the present embodiment, it is a disc shape having no shape anisotropy.
【００１３】このように構成された本実施例は、磁石材
料が等方性であり、形状異方性もないため、任意の方向
に正確に磁化することができる。従って磁気抵抗素子が
必要とするバイアス磁石方向に正確に着磁することがで
き、前実施例と同様に不平衡電圧の発生を防止すること
ができる。In this embodiment thus constructed, the magnet material is isotropic and has no shape anisotropy, so that it can be magnetized accurately in any direction. Therefore, it is possible to accurately magnetize in the direction of the bias magnet required by the magnetoresistive element, and it is possible to prevent the generation of an unbalanced voltage as in the previous embodiment.
【００１４】なお、第１の実施例では、バイアス磁石１
１が形状異方性を有するため、Ｓｉ基板１０との接着に
は、その位置合わせに精度を要するが、本実施例ではそ
の必要がない。またバイアス磁石としてフェライト磁石
を用い、磁気抵抗パターンにＮｉ−Ｆｅ膜を用いると、
Ｎｉ−Ｆｅ膜の抵抗変化率と磁石の磁力の温度特性が近
い値をしているので、温度特性の良い磁気センサを作る
ことができる。In the first embodiment, the bias magnet 1
Since No. 1 has shape anisotropy, the bonding with the Si substrate 10 requires precision in its alignment, but this is not necessary in this embodiment. If a ferrite magnet is used as the bias magnet and a Ni-Fe film is used for the magnetoresistive pattern,
Since the resistance change rate of the Ni—Fe film and the temperature characteristic of the magnetic force of the magnet are close to each other, a magnetic sensor having good temperature characteristics can be manufactured.
【００１５】[0015]
【発明の効果】本発明に依れば、バイアス磁石として等
方性磁石を用いることにより、着磁方向を所望の方向に
正確に合わせることができるため、磁気抵抗素子の必要
とするバイアス磁界方向に合わせて正確な着磁ができ不
平衡電圧の発生を防止することができる。これにより歩
留り良くバイアス磁石付き磁気センサを製造することが
できる。According to the present invention, by using an isotropic magnet as the bias magnet, the magnetizing direction can be accurately aligned with a desired direction. It is possible to accurately magnetize and prevent the generation of an unbalanced voltage. As a result, a magnetic sensor with a bias magnet can be manufactured with good yield.
【図１】本発明の第１の実施例を示す斜視図である。FIG. 1 is a perspective view showing a first embodiment of the present invention.
【図２】本発明の第２の実施例を示す斜視図である。FIG. 2 is a perspective view showing a second embodiment of the present invention.
【図３】磁気抵抗素子の出力特性を示す図である。FIG. 3 is a diagram showing output characteristics of a magnetoresistive element.
【図４】従来の磁気センサを示す図である。FIG. 4 is a diagram showing a conventional magnetic sensor.
【図５】バイアス磁界方向のずれと出力の対称性の関係
を示す図である。FIG. 5 is a diagram showing a relationship between a deviation in a bias magnetic field direction and output symmetry.
１０…Ｓｉ基板 １１…バイアス磁石 １２…磁気抵抗素子 10 ... Si substrate 11 ... Bias magnet 12 ... Magnetoresistive element
───────────────────────────────────────────────────── フロントページの続き (72)発明者 倉島 茂美 神奈川県川崎市中原区上小田中1015番地 富士通株式会社内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigumi Kurashima 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited
Claims (3)
した磁気抵抗素子（１２）と、該磁気抵抗素子（１２）
にバイアス磁界を印加するバイアス磁石（１１）とを具
備してなる磁気センサにおいて、 上記バイアス磁石（１１）に等方性磁石を用い、着磁の
角度によって磁気抵抗素子（１２）に生ずる不平衡電圧
を調整することを特徴とする磁気センサ。1. A magnetoresistive element (12) having a bridge circuit composed of a magnetoresistive pattern, and the magnetoresistive element (12).
A magnetic sensor comprising a bias magnet (11) for applying a bias magnetic field to the magnetic field, wherein an isotropic magnet is used as the bias magnet (11), and an unbalance occurs in the magnetoresistive element (12) depending on the angle of magnetization. A magnetic sensor characterized by adjusting a voltage.
形にして形状異方性を付与したことを特徴とする磁気セ
ンサ。2. A magnetic sensor characterized in that the bias magnet (11) has a rectangular shape to impart shape anisotropy.
にして形状異方性を付与しないことを特徴とする磁気セ
ンサ。3. A magnetic sensor characterized in that the shape of the bias magnet (11) is circular so that shape anisotropy is not imparted.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4150590A JPH05341026A (en) | 1992-06-10 | 1992-06-10 | Magnetic sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4150590A JPH05341026A (en) | 1992-06-10 | 1992-06-10 | Magnetic sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05341026A true JPH05341026A (en) | 1993-12-24 |
Family
ID=15500215
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4150590A Withdrawn JPH05341026A (en) | 1992-06-10 | 1992-06-10 | Magnetic sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05341026A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1996006329A1 (en) * | 1994-08-23 | 1996-02-29 | Matsushita Electric Industrial Co., Ltd. | Magnetic signal detector |
-
1992
- 1992-06-10 JP JP4150590A patent/JPH05341026A/en not_active Withdrawn
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1996006329A1 (en) * | 1994-08-23 | 1996-02-29 | Matsushita Electric Industrial Co., Ltd. | Magnetic signal detector |
| US5663644A (en) * | 1994-08-23 | 1997-09-02 | Matsushita Electric Industrial Co., Ltd. | Magnetoresistive sensor having a bias field applied at approximately 56° |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Application deemed to be withdrawn because no request for examination was validly filed |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 19990831 |