JPS631548B2 - - Google Patents
Info
- Publication number
- JPS631548B2 JPS631548B2 JP54029210A JP2921079A JPS631548B2 JP S631548 B2 JPS631548 B2 JP S631548B2 JP 54029210 A JP54029210 A JP 54029210A JP 2921079 A JP2921079 A JP 2921079A JP S631548 B2 JPS631548 B2 JP S631548B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic field
- amplitude
- signal
- output
- magnetoresistive
- 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.)
- Expired
Links
- 230000005291 magnetic effect Effects 0.000 claims description 88
- 238000010586 diagram Methods 0.000 description 10
- 238000000034 method Methods 0.000 description 9
- 238000003860 storage Methods 0.000 description 8
- 238000001514 detection method Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 7
- 239000003990 capacitor Substances 0.000 description 3
- 230000005294 ferromagnetic effect Effects 0.000 description 3
- 230000005415 magnetization Effects 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- 239000010409 thin film Substances 0.000 description 3
- 239000004020 conductor Substances 0.000 description 2
- 230000010354 integration Effects 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- JRBRVDCKNXZZGH-UHFFFAOYSA-N alumane;copper Chemical compound [AlH3].[Cu] JRBRVDCKNXZZGH-UHFFFAOYSA-N 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000007274 generation of a signal involved in cell-cell signaling Effects 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910000889 permalloy Inorganic materials 0.000 description 1
- 230000008929 regeneration Effects 0.000 description 1
- 238000011069 regeneration method Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Inorganic materials [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
Landscapes
- Measuring Magnetic Variables (AREA)
Description
【発明の詳細な説明】
本発明は信号磁界の強弱を磁気抵抗効果を利用
して検出する磁気センサーに関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic sensor that detects the strength of a signal magnetic field using a magnetoresistive effect.
従来、この種の磁気センサーでは、信号磁界に
対する感度を高め、線型性を改善するために、磁
気抵抗効果素子に直流バイアス磁界を印加してい
る。信号磁界に対する磁気抵抗効果素子の抵抗変
化量は、せいぜい数パーセントであるので、この
ままでは、信号成分は大きな直流電圧の上に重畳
された形で発生する。従つて、この磁気センサー
で、交流磁界だけでなく直流磁界をも検出するた
めに、通常は前記磁気抵抗効果素子のほかに補償
用の抵抗もしくは第２の磁気抵抗効果素子を設
け、この両者の差動出力を広帯域の直流増幅器で
増幅したものを信号出力として取り出していた。 Conventionally, in this type of magnetic sensor, a DC bias magnetic field is applied to the magnetoresistive element in order to increase sensitivity to a signal magnetic field and improve linearity. Since the amount of change in resistance of the magnetoresistive element with respect to the signal magnetic field is at most a few percent, the signal component will be generated as it is superimposed on a large DC voltage. Therefore, in order to detect not only an alternating current magnetic field but also a direct current magnetic field with this magnetic sensor, a compensating resistor or a second magnetoresistive element is usually provided in addition to the magnetoresistive element, and both of these are combined. The differential output was amplified by a wideband DC amplifier and then output as a signal output.
この様な磁気センサーにおいては、磁気抵抗効
果素子と補償用抵抗、もしくは磁気抵抗素子間の
抵抗値のバラツキによつて生じる直流オフセツト
電圧及び直流増幅器の直流オフセツト電圧のため
に、信号出力だけを有効に取り出すことは大変困
難であつた。 In such magnetic sensors, only the signal output is effective due to the DC offset voltage caused by the variation in resistance between the magnetoresistive element and the compensation resistor, or the magnetoresistive element, and the DC offset voltage of the DC amplifier. It was very difficult to take it out.
本発明の目的は、上記欠点を解決した、高性能
な磁気センサーを提供することにある。 An object of the present invention is to provide a high-performance magnetic sensor that solves the above-mentioned drawbacks.
本発明の特徴は、信号磁界の強弱を磁気抵抗効
果を利用して検出する磁気センサーにおいて、所
定の間隔を保つて互いに平行に並置された２つの
磁気抵抗効果素子と、従来の直流バイアス磁界の
代りに前記２つの磁気抵抗効果素子に互いに逆位
相の微小振幅交流バイアス磁界印加手段を設けて
信号磁界の強弱を、前記交流バイアス磁界を搬送
波として振幅変調された形で交流的に差動検出し
それを復調する新たな方法により、従来の直流的
な信号磁界検出方式で最大の問題となつていた、
直流オフセツト電圧に起因する欠点を克服でき、
その結果高性能な磁気センサーを実現できること
にある。 The present invention is characterized in that, in a magnetic sensor that detects the strength of a signal magnetic field by using the magnetoresistive effect, two magnetoresistive effect elements are arranged parallel to each other with a predetermined interval maintained, and a conventional DC bias magnetic field is used. Instead, the two magnetoresistive elements are provided with means for applying minute amplitude alternating current bias magnetic fields having phases opposite to each other, and the strength of the signal magnetic field is differentially detected in an alternating current manner in an amplitude modulated form using the alternating bias magnetic field as a carrier wave. A new method for demodulating it solves the biggest problem with conventional DC signal magnetic field detection methods.
Can overcome the drawbacks caused by DC offset voltage,
As a result, a high-performance magnetic sensor can be realized.
すなわち、本発明の構成は、ほぼ同位相・同一
振幅の信号磁界が作用する間隔を保つて互いに平
行に並置された２つの磁気抵抗効果素子と、これ
らの磁気抵抗効果素子を駆動する回路と、前記２
つの磁気抵抗効果素子に互いに逆位相の微小振幅
交流バイアス磁界を印加する手段と、前記２つの
磁気抵抗効果素子の差動出力を増幅する差動増幅
器と、この差動増幅器出力波形を整流して積分す
る振幅復調回路とから成る。 That is, the configuration of the present invention includes two magnetoresistive elements that are arranged in parallel with each other with a spacing such that signal magnetic fields of approximately the same phase and amplitude act, and a circuit that drives these magnetoresistive elements. Said 2
means for applying minute amplitude alternating current bias magnetic fields of mutually opposite phases to the two magnetoresistive elements; a differential amplifier for amplifying the differential output of the two magnetoresistive elements; and a means for rectifying the output waveform of the differential amplifier. It consists of an amplitude demodulation circuit that performs integration.
磁気抵抗効果素子へ交流バイアス磁界を印加し
て再生する方式は、IEEE Transaction on
Audio，Vol Au−13，No.２，March 1965，P41
〜43に示されている。これは、信号磁界に比べて
大きな振幅を有する交流バイアス磁界を印加して
信号磁界を検知し、このバイアス磁界の向きが逆
の時の出力振幅エンベロープの差を信号として再
生するもので、これと全く同一原理に基づく例と
して、特開昭53−57810号、又この方式を発展さ
せた例として米国特許第3979775号等が報告され
ている。しかし、この方式では原理上、交流バイ
アス磁界の強度を信号磁界に比べて大きくする必
要があるので、交流バイアス磁界印加手段の構成
が複雑になつたり信号磁界発生源への干渉を生じ
易い等の欠点を有する。 The method of reproducing by applying an AC bias magnetic field to a magnetoresistive element is described in the IEEE Transaction on
Audio, Vol Au−13, No.2, March 1965, P41
~43. This applies an AC bias magnetic field with a larger amplitude than the signal magnetic field, detects the signal magnetic field, and reproduces the difference in the output amplitude envelope when the bias magnetic field is in the opposite direction as a signal. An example based on exactly the same principle has been reported in Japanese Patent Application Laid-Open No. 53-57810, and an example in which this method has been developed is US Pat. No. 3,979,775. However, in principle, this method requires the strength of the AC bias magnetic field to be larger than that of the signal magnetic field, so the structure of the AC bias magnetic field application means becomes complicated and interference with the signal magnetic field generation source is likely to occur. It has its drawbacks.
本発明によれば、以上のような欠点をも容易に
改善できる。 According to the present invention, the above-mentioned drawbacks can be easily improved.
次に本発明の実施例について図面を参照して説
明する。 Next, embodiments of the present invention will be described with reference to the drawings.
第１図は本発明の一実施例を示したものであ
り、これによれば、２つの磁気抵抗効果素子１，
２がそれぞれ絶縁層３，４を介して導電体層５，
６を有し、かつ互いに平行となるように基板７上
に形成されている。導電体層５，６は、互いに逆
位相の交流電流が流れるように交流発振器８に結
線されており、前記磁気抵抗効果素子１，２へ互
いに逆位相の交流バイアス磁界を印加する手段を
形成している。又、磁気抵抗効果素子１，２は、
定電流回路９で駆動されており、それらの出力端
子１０，１１は再生回路１２に結線されている。
この再生回路１２は、前記２つの磁気抵抗効果素
子の交流出力を差動増幅する、差動増幅器１３
と、この差動増幅器出力波形の直流分オフセツト
をカツトするコンデンサ４１と、コンデンサ４１
からの出力波形を整流するダイオード等から成る
整流回路１４と、その整流された出力を積分する
積分回路１５とから成る振幅復調回路１６とから
成る。 FIG. 1 shows an embodiment of the present invention, in which two magnetoresistive elements 1,
2 are connected to the conductive layer 5, via the insulating layers 3 and 4, respectively.
6, and are formed on the substrate 7 so as to be parallel to each other. The conductive layers 5 and 6 are connected to an AC oscillator 8 so that alternating currents having mutually opposite phases flow therethrough, and form means for applying alternating current bias magnetic fields having mutually opposite phases to the magnetoresistive elements 1 and 2. ing. Moreover, the magnetoresistive elements 1 and 2 are
It is driven by a constant current circuit 9, and its output terminals 10 and 11 are connected to a reproducing circuit 12.
This reproducing circuit 12 includes a differential amplifier 13 that differentially amplifies the AC outputs of the two magnetoresistive elements.
, a capacitor 41 for cutting off the DC component offset of this differential amplifier output waveform, and a capacitor 41
The amplitude demodulation circuit 16 includes a rectifier circuit 14 made of a diode or the like that rectifies the output waveform from the rectifier, and an integrator circuit 15 that integrates the rectified output.
この実施例の動作を第２図、第３図を用いて説
明する。 The operation of this embodiment will be explained using FIGS. 2 and 3.
第２図は、本発明の信号磁界検知の原理を示す
図、第３図は、本発明の再生過程を説明する図で
ある。強磁性磁気抵抗効果素子のストライプ幅方
向印加磁界Ｈとその磁気抵抗効果素子の抵抗変化
量ΔRとの関係は周知の如く、２１に示すように
印加磁界Ｈの大きさが飽和磁界H0を越えない範
囲（｜Ｈ｜＜H0）では、近似的に
ΔR∝H2
と表わされる。 FIG. 2 is a diagram showing the principle of signal magnetic field detection according to the present invention, and FIG. 3 is a diagram explaining the reproduction process according to the present invention. The relationship between the magnetic field H applied in the stripe width direction of the ferromagnetic magnetoresistive element and the resistance change amount ΔR of the magnetoresistive element is well known, as shown in 21, when the magnitude of the applied magnetic field H exceeds the saturation magnetic field H0 . In the range where there is no difference (|H|<H 0 ), it is approximately expressed as ΔR∝H 2 .
従つて、 ｜∂・ΔR／∂H｜∝｜Ｈ｜ が成り立つ。 Therefore, ｜∂・ΔR／∂H｜∝｜H｜ holds true.
これは磁気抵抗効果素子に、ある信号磁界Ｈを
中心にして微小振幅の交流磁界を印加した時の、
ΔRの変化量が信号磁界Ｈの大きさに比例するこ
とを示す。すなわち、磁気抵抗効果素子１に微小
振幅の交流バイアス磁界２２を加えながら、信号
磁界Hsを検出すると、この信号磁界Hsの大きさ
に、ほぼ比例した大きさの交流的なΔRの変化２
４を生じる。 This is when an alternating current magnetic field of minute amplitude is applied to the magnetoresistive element with a certain signal magnetic field H as the center.
This shows that the amount of change in ΔR is proportional to the magnitude of the signal magnetic field H. That is, when a signal magnetic field Hs is detected while applying a minute amplitude AC bias magnetic field 22 to the magnetoresistive element 1, an AC-like change in ΔR 2 whose magnitude is approximately proportional to the magnitude of the signal magnetic field Hs occurs.
yields 4.
さらに、同じ信号磁界Hsが印加される様に配
置されたもう１つの磁気抵抗効果素子２に２２と
逆位相で同一振幅の微小振幅交流バイアス磁界２
３を加えながら再生すると、この磁気抵抗効果素
子２からは、２４と逆位相で同一振幅のΔRの変
化２５を生じる。これらのΔRの交流的変化を、
磁気抵抗効果素子１，２に流す電流を介して電圧
の変化に直し、さらに、これらの差動出力を取る
ことにより、信号磁界Hsの大きさに比例し、同
相ノイズが除去され交流振幅が倍になつた良好な
る交流出力が得られる。 Furthermore, another magnetoresistive effect element 2 arranged so that the same signal magnetic field Hs is applied is applied with a minute amplitude alternating current bias magnetic field 2 having the opposite phase and the same amplitude as 22.
When reproduction is performed while adding 3, this magnetoresistive element 2 produces a change 25 in ΔR with the opposite phase and the same amplitude as 24. These alternating current changes in ΔR are
By correcting the voltage change through the current flowing through the magnetoresistive elements 1 and 2, and by taking these differential outputs, the common mode noise is removed and the AC amplitude is doubled in proportion to the magnitude of the signal magnetic field Hs. A good AC output can be obtained.
例えば第３図ａに示すような信号磁界２６が前
記磁気抵抗効果素子１，２のストライプ幅方向
（ｘ方向）に加わつた場合、差動増幅器出力１７
として第３図ｂに示す様に、交流バイアス磁界を
搬送波として信号磁界２６で振幅変調された波形
に類似の出力２７を生じる。これを整流回路１４
と積分回路１５とから成る振幅復調回路１６を通
すことにより第３図ｃに示す整流出力２８を経
て、第３図ｄに示す復調出力２９を得る。この復
調出力２９の振幅は先述の原理に従い、信号磁界
２６の振幅に比例した大きさを有する。 For example, when a signal magnetic field 26 as shown in FIG. 3a is applied in the stripe width direction (x direction) of the magnetoresistive elements 1 and 2, the differential amplifier output 17
As shown in FIG. 3b, an output 27 similar to the waveform amplitude modulated by the signal magnetic field 26 using the AC bias magnetic field as a carrier wave is produced. This is the rectifier circuit 14
The signal is passed through an amplitude demodulation circuit 16 consisting of an integrator circuit 15 and a rectified output 28 shown in FIG. 3c, and then a demodulated output 29 shown in FIG. 3d is obtained. The amplitude of this demodulated output 29 has a magnitude proportional to the amplitude of the signal magnetic field 26 in accordance with the above-mentioned principle.
次に第１図に示す磁気センサーの他の応用例に
ついて説明する。 Next, another application example of the magnetic sensor shown in FIG. 1 will be explained.
第４図は前記磁気センサーを一定間隔Ｌのビツ
ト長を有する磁化３１の形で記録されている磁気
信号の検出に応用した例を示す。２つの磁気抵抗
効果素子１，２はその間隔W1が2nL（ｎは正の整
数）の大きさになるよう平行に形成されており、
これが磁気記憶媒体３０から生じる信号磁界３２
の水平成分を検知できるように前記磁気記憶媒体
３０に対し距離Ｄを隔てて並置されている。 FIG. 4 shows an example in which the magnetic sensor is applied to the detection of a magnetic signal recorded in the form of magnetization 31 having a bit length of constant interval L. The two magnetoresistive elements 1 and 2 are formed in parallel so that the distance W1 between them is 2nL (n is a positive integer).
This is the signal magnetic field 32 generated from the magnetic storage medium 30.
The magnetic recording medium 30 is arranged at a distance D from the magnetic storage medium 30 so that the horizontal component of the magnetic recording medium 30 can be detected.
この動作を第５図を用いて説明する。ａに示す
磁気記憶媒体３０のｘ方向の移動に伴い、前記磁
気抵抗効果素子１及び２には両者の間隔W1のた
めにほぼ同一振幅、同位相のｂに示すような水平
方向信号磁界３３が印加される。同様にして、差
動増幅器出力１７としてｃに示すように、交流バ
イアス磁界を搬送波として信号磁界３３で振幅変
調された波形に類した出力３４を得る。これを振
幅復調回路１５に通すことによりｄに示すよう
に、信号磁界３３の振幅に比例した大きさの振幅
を有する復調出力３５を得る。 This operation will be explained using FIG. 5. As the magnetic storage medium 30 moves in the x direction as shown in a, the magnetoresistive elements 1 and 2 receive a horizontal signal magnetic field 33 of approximately the same amplitude and phase as shown in b due to the distance W1 between them. applied. Similarly, as shown in c as the differential amplifier output 17, an output 34 similar to a waveform whose amplitude is modulated by the signal magnetic field 33 using the AC bias magnetic field as a carrier wave is obtained. By passing this through the amplitude demodulation circuit 15, a demodulated output 35 having an amplitude proportional to the amplitude of the signal magnetic field 33 is obtained, as shown in d.
第６図は本発明の他の実施例を示したもので、
第１図の実施例と比べると、２つの磁気抵抗効果
素子３７と３８が絶縁層３９及び４０を介して共
通の導電体層３６を挾むように形成されている点
が異なる。 FIG. 6 shows another embodiment of the present invention,
This embodiment differs from the embodiment shown in FIG. 1 in that two magnetoresistive elements 37 and 38 are formed so as to sandwich a common conductive layer 36 with insulating layers 39 and 40 in between.
この場合、導電体層３６は、交流発振器８に結
線されて、前記磁気抵抗効果素子３７及び３８へ
互いに逆位相の交流バイアス磁界を印加する手段
を形成することにより、Ｚ方向の信号磁界Hsを
第１図に示した実施例と同一の再生過程を経て検
出できる。 In this case, the conductor layer 36 is connected to the AC oscillator 8 to form a means for applying an AC bias magnetic field having opposite phases to the magnetoresistive elements 37 and 38, thereby generating a signal magnetic field Hs in the Z direction. Detection can be performed through the same regeneration process as in the embodiment shown in FIG.
又、第４図の場合と同様にして、このタイプの
磁気センサーも第７図に示すように一定の間隔Ｌ
のビツト長をする磁化３１の形で記録されてい
る。磁気信号の検出に応用できる。この場合、２
つの磁気抵抗効果素子３７，３８はその間隔W2
が2nL（ｎは正の整数）の大きさになるように形
成されており、これが磁気記憶媒体３０から生じ
る信号磁界３２の垂直成分を検知できるように、
前記磁気記憶媒体３０に対し、垂直に配置され
る。磁気記憶媒体３０のｘ方向の移動に伴い、前
記磁気抵抗効果素子３７及び３８にはほぼ同一振
幅、同位相の垂直方向信号磁界が印加され、第５
図に示したのと同様の動作により、前記信号磁界
の垂直成分の振幅に比例した大きさの振幅を有す
る復調出力を得る。 Also, similar to the case of FIG. 4, this type of magnetic sensor also has a fixed interval L as shown in FIG.
It is recorded in the form of magnetization 31 having a bit length of . It can be applied to detecting magnetic signals. In this case, 2
The distance between the two magnetoresistive elements 37 and 38 is W2
is formed to have a size of 2nL (n is a positive integer), so that the vertical component of the signal magnetic field 32 generated from the magnetic storage medium 30 can be detected.
It is arranged perpendicularly to the magnetic storage medium 30. As the magnetic storage medium 30 moves in the x direction, vertical signal magnetic fields having approximately the same amplitude and the same phase are applied to the magnetoresistive elements 37 and 38, and the fifth
By the same operation as shown in the figure, a demodulated output having an amplitude proportional to the amplitude of the vertical component of the signal magnetic field is obtained.
磁気抵抗効果素子１，２，３７，３８としては
パーマロイやコバルト等を主成分とする金属強磁
性合金をシリコン単結晶、ガラス、セラミツク等
の表面の滑らかな基板７上に、厚さ数百オングス
トローム、ストライプ巾数〜数十ミクロン、長さ
数十ミクロン〜数ミリメートルの形状になるよ
う、両端の電気端子と共に薄膜作製技術で作製さ
れたものが用いられる。導電体層５，６，３６と
しては厚さ数千オングストローム〜数十ミクロン
の金、銅アルミニウム等の薄膜、又絶縁体層３，
４，３９，４０としては厚さ数千オングストロー
ム〜数ミクロンのSiO，SiO2，Al2O3等の薄膜が
適する。 The magnetoresistive elements 1, 2, 37, and 38 are made of a metal ferromagnetic alloy whose main component is permalloy, cobalt, etc., on a substrate 7 with a smooth surface made of silicon single crystal, glass, ceramic, etc., to a thickness of several hundred angstroms. , a stripe fabricated by thin film fabrication technology with electrical terminals at both ends is used so as to have a stripe width of several tens of microns to several tens of microns to several millimeters in length. The conductive layers 5, 6, and 36 are thin films of gold, copper aluminum, etc., with a thickness of several thousand angstroms to several tens of microns, and the insulating layers 3,
As 4, 39, and 40, thin films of SiO, SiO 2 , Al 2 O 3 or the like having a thickness of several thousand angstroms to several microns are suitable.
本発明は、以上説明したように、信号磁界の強
弱を磁気抵抗効果を利用して検出する磁気センサ
ーにおいて、所定間隔を保つて互いに平行に並置
された２つの磁気抵抗効果素子と、従来の直流バ
イアス磁界のかわりに前記２つの磁気抵抗効果素
子に互いに逆位相の微小振幅交流バイアス磁界を
印加する手段及び振幅復調回路を設けて、信号磁
界を交流的に差動検出し復調することにより、従
来の直流的な信号磁界検出方式で最大の問題とな
つていた、直流オフセツト電圧に起因する種々の
欠点を克服できる効果がある。又、本発明の再生
方式は、従来の交流バイアス磁界印加方式と比べ
て交流バイアス磁界強度が微小であるので、信号
発生源の特性に悪影響を与えないこと、及び交流
バイアス磁界印加手段の構成が容易であること、
更には差動検出しているので、再生感度が高い等
の利点も兼ね備えている。 As explained above, the present invention provides a magnetic sensor that detects the strength of a signal magnetic field by using the magnetoresistive effect, in which two magnetoresistive effect elements arranged parallel to each other with a predetermined interval and a conventional direct current In place of the bias magnetic field, a means for applying a minute amplitude alternating current bias magnetic field of mutually opposite phases to the two magnetoresistive elements and an amplitude demodulation circuit are provided to differentially detect and demodulate the signal magnetic field in an alternating current manner. This has the effect of overcoming various drawbacks caused by the DC offset voltage, which has been the biggest problem in the DC signal magnetic field detection method. In addition, since the reproduction method of the present invention has a minute AC bias magnetic field strength compared to the conventional AC bias magnetic field application method, it does not adversely affect the characteristics of the signal generation source, and the configuration of the AC bias magnetic field application means is be easy;
Furthermore, since differential detection is used, it also has advantages such as high playback sensitivity.
第１図は本発明の一実施例を示す概略斜視図、
第２図は本発明の再生原理を示す図、第３図は本
発明の検出過程を示す図で、ａは信号磁界を示す
図、ｂは振幅変調された出力を示す図、ｃは整流
された出力を示す図、ｄは復調出力を示す図であ
る。第４図は本発明の応用例を示す概略斜視図、
第５図は第４図に示す応用例の動作を示す図で、
ａは磁気記憶媒体を示す図、ｂは信号磁界を示す
図、ｃは振幅変調された出力を示す図、ｄは復調
出力を示す図である。第６図は本発明の第２の実
施例を示す概略斜視図、第７図は第６図に示す実
施例の応用例を示す概略斜視図である。
図において、１，２，３７，３８……磁気抵抗
効果素子、３，４，３９，４０……絶縁体層、
５，６，３６……導電体層、７……基板、８……
発振器、９……定電流源回路、１０，１１……磁
気抵抗効果素子の出力端子、１２……再生回路、
１３……差動増幅器、１４……整流器、１５……
積分回路、１６……振幅復調回路、１７……差動
増幅器出力端子、１８……整流器出力端子、１９
……復調回路出力端子、２０，３２……信号磁
界、２１……強磁性磁気抵抗効果素子の静特性曲
線、２２，２３……微小振幅交流バイアス磁界、
２４，２５……交流的なΔRの変化、２６，３３
……ストライプ巾方向信号磁界、２７，３４……
差動増幅器出力波形、２８……整流回路出力波
形、２９，３５……振幅復調回路出力波形、３０
……磁気記憶媒体、３１……磁化、４１……コン
デンサ。
FIG. 1 is a schematic perspective view showing an embodiment of the present invention;
Fig. 2 is a diagram showing the reproduction principle of the present invention, Fig. 3 is a diagram showing the detection process of the present invention, where a shows the signal magnetic field, b shows the amplitude modulated output, and c shows the rectified output. d is a diagram showing the demodulated output. FIG. 4 is a schematic perspective view showing an application example of the present invention;
FIG. 5 is a diagram showing the operation of the application example shown in FIG.
3A is a diagram showing a magnetic storage medium, b is a diagram showing a signal magnetic field, c is a diagram showing an amplitude-modulated output, and d is a diagram showing a demodulated output. FIG. 6 is a schematic perspective view showing a second embodiment of the present invention, and FIG. 7 is a schematic perspective view showing an application example of the embodiment shown in FIG. In the figure, 1, 2, 37, 38... magnetoresistive element, 3, 4, 39, 40... insulator layer,
5, 6, 36... Conductor layer, 7... Substrate, 8...
Oscillator, 9... Constant current source circuit, 10, 11... Output terminal of magnetoresistive element, 12... Reproduction circuit,
13... Differential amplifier, 14... Rectifier, 15...
Integration circuit, 16... Amplitude demodulation circuit, 17... Differential amplifier output terminal, 18... Rectifier output terminal, 19
... Demodulation circuit output terminal, 20, 32 ... Signal magnetic field, 21 ... Static characteristic curve of ferromagnetic magnetoresistive element, 22, 23 ... Minute amplitude AC bias magnetic field,
24, 25...Change in AC-like ΔR, 26, 33
...Stripe width direction signal magnetic field, 27, 34...
Differential amplifier output waveform, 28... Rectifier circuit output waveform, 29, 35... Amplitude demodulation circuit output waveform, 30
...Magnetic storage medium, 31...Magnetization, 41...Capacitor.
Claims (1)
２つの磁気抵抗効果素子と、これら２つの磁気抵
抗効果素子に一定電流を供給する駆動回路と、そ
れぞれの磁気抵抗効果素子に絶縁層を介して積層
配置される導電層と、この２つの導電層に、互い
に逆位相の交流電流を流し前記２つの磁気抵抗効
果素子に互いに逆位相の微小振幅交流バイアス磁
界を印加する交流発振器と、前記２つの磁気抵抗
効果素子と接続し、これらの差動出力を増幅する
差動増幅器と、この差動増幅器出力波形を整流し
て積分する振幅復調回路とから成ることを特徴と
する磁気センサー。1. Two magnetoresistive elements arranged parallel to each other with a constant interval, a drive circuit that supplies a constant current to these two magnetoresistive elements, and a drive circuit that supplies a constant current to each magnetoresistive element through an insulating layer. a laminated conductive layer; an AC oscillator that applies alternating current with opposite phases to the two magnetoresistive elements; A magnetic sensor comprising: a differential amplifier that is connected to a magnetoresistive element and amplifies the differential output thereof; and an amplitude demodulation circuit that rectifies and integrates the output waveform of the differential amplifier.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2921079A JPS55121161A (en) | 1979-03-13 | 1979-03-13 | Magnetic sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2921079A JPS55121161A (en) | 1979-03-13 | 1979-03-13 | Magnetic sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS55121161A JPS55121161A (en) | 1980-09-18 |
| JPS631548B2 true JPS631548B2 (en) | 1988-01-13 |
Family
ID=12269821
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2921079A Granted JPS55121161A (en) | 1979-03-13 | 1979-03-13 | Magnetic sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS55121161A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58154680A (en) * | 1982-03-10 | 1983-09-14 | Copal Co Ltd | Magnetic sensor |
-
1979
- 1979-03-13 JP JP2921079A patent/JPS55121161A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS55121161A (en) | 1980-09-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0544642B1 (en) | Magnetic transducer head apparatus utilizing the magnetoresistance effect | |
| EP0484474B1 (en) | Shorted dual element magnetoresistive reproduce head exhibiting high density signal amplification | |
| US4686472A (en) | Magnetic sensor having closely spaced and electrically parallel magnetoresistive layers of different widths | |
| EP0103352B1 (en) | Magnetic sensor, particularly playback head for magnetic recording media | |
| JPS6114572B2 (en) | ||
| JPH0473201B2 (en) | ||
| JPS60182503A (en) | Magneto-resistance effect type magnetic head | |
| JPS6357741B2 (en) | ||
| JPS631548B2 (en) | ||
| JPS6259269B2 (en) | ||
| JP3639407B2 (en) | Magnetic head | |
| JPH022086B2 (en) | ||
| JPH0719341B2 (en) | Multi-track magnetoresistive effect magnetic head | |
| JPS63138515A (en) | Thin film magnetic head and its reproduction system | |
| JP2583851B2 (en) | Magnetoresistive magnetic head | |
| JPH03171410A (en) | Thin film magnetic head for recording and reproducing | |
| JPH0532803B2 (en) | ||
| JPH0542049B2 (en) | ||
| JPH1021515A (en) | Magnetic head pattern, production of magnetic head pattern, method for determining dc bias current of magnetic head obtainable from magnetic head pattern, and magnetic information reproducing device formed by using this magnetic head | |
| JP3537380B2 (en) | Magnetic head and magnetic reproducing device | |
| JPS6032245B2 (en) | magnetoresistive head | |
| JPH05159247A (en) | Magneto-resistance effect head | |
| JPS58224430A (en) | Hybrid thin film integrated head | |
| JPS60263310A (en) | Magneto-resistance effect type magnetic head device | |
| JPH0532804B2 (en) |