JPH071561B2 - Magneto-optical reproducing magnetic head - Google Patents
Magneto-optical reproducing magnetic headInfo
- Publication number
- JPH071561B2 JPH071561B2 JP61026951A JP2695186A JPH071561B2 JP H071561 B2 JPH071561 B2 JP H071561B2 JP 61026951 A JP61026951 A JP 61026951A JP 2695186 A JP2695186 A JP 2695186A JP H071561 B2 JPH071561 B2 JP H071561B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- film
- magnetic core
- core
- light
- 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 - Lifetime
Links
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B11/00—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor
- G11B11/10—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field
- G11B11/105—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field using a beam of light or a magnetic field for recording by change of magnetisation and a beam of light for reproducing, i.e. magneto-optical, e.g. light-induced thermomagnetic recording, spin magnetisation recording, Kerr or Faraday effect reproducing
- G11B11/10532—Heads
- G11B11/10541—Heads for reproducing
- G11B11/10543—Heads for reproducing using optical beam of radiation
- G11B11/10547—Heads for reproducing using optical beam of radiation interacting with the magnetisation of an intermediate transfer element, e.g. magnetic film, included in the head
Description
【発明の詳細な説明】 〔発明の利用分野〕 本発明は、高精細度のビデオ信号などの再生に用いて好
適な光再生磁気ヘツドに関する。Description: FIELD OF THE INVENTION The present invention relates to an optical reproducing magnetic head suitable for reproducing a high-definition video signal or the like.
近年における磁気記録の主なる課題は、記録媒体の容量
を拡大するための高記録密度化と高速にアクセスを可能
とするための（すなわち、記録可能帯域を拡大するため
の）高周波化である。たとえば、最近、高精細度のカラ
ーテレビジヨン方式が大いに注目されているが、かかる
方式のビデオ信号は従来方式のビデオ信号に比べて周波
数帯域が広い。このような広帯域ビデオ信号を高密度記
録する場合、通常、磁気媒体の走行速度を低くすること
により、トラツクの幅を狭くし、トラツクピツチをなく
すようにして高密度記録化をはかつているが、再生ヘツ
ドとして従来の巻線型磁気ヘツドを用いた場合、これは
磁気媒体の磁化による磁束の変化を直接巻線によつて電
気信号に変換するために、トラツクの幅が狭いことによ
つて磁気ヘツドの再生出力が低下し、再生アンプなどに
発生するノイズの影響を受けてC/N（キヤリア／ノイ
ズ）が劣化する。特に、高精細度のビデオ信号の記録再
生では、このC/Nの劣化が画質に顕著に現われることに
なる。そこで、磁気ヘツドの再生出力を高めるために、
その巻線数を増加させることが考えられるが、これによ
ると、磁気ヘツドのインダクタンスが増加して伝送帯域
が狭くなり、やはり再生画像の画質が低下して高周波化
に対応できない。The main problems of magnetic recording in recent years are increasing the recording density to increase the capacity of the recording medium and increasing the frequency to enable high-speed access (that is, to increase the recordable band). For example, recently, a high-definition color television system has received much attention, but the video signal of this system has a wider frequency band than the video signal of the conventional system. In the case of high-density recording of such a wideband video signal, usually, the traveling speed of the magnetic medium is reduced to narrow the width of the track and eliminate the track pitch, thus achieving high-density recording. When a conventional wire wound type magnetic head is used as the head, this is because the change in the magnetic flux due to the magnetization of the magnetic medium is directly converted into an electric signal by the winding, and the narrow width of the track causes The playback output drops and the C / N (carrier / noise) deteriorates under the influence of noise generated in the playback amplifier. In particular, when recording and reproducing a high-definition video signal, the deterioration of C / N becomes noticeable in the image quality. Therefore, in order to increase the reproduction output of the magnetic head,
It is conceivable to increase the number of windings, but according to this, the inductance of the magnetic head increases and the transmission band becomes narrow, and the image quality of the reproduced image also deteriorates, and it cannot cope with high frequency.
そこで、かかる問題を解消するために、光磁気効果を利
用して高密度に記録された情報を再生するようにした方
式が提案されている（信学技報Vol.1 No.42 1979.5 pp.
21−28 野村龍男らによる論文「光磁気録画方式の一検
討」）。これは、磁気媒体の磁化による磁束変化を直接
巻線によつて電気信号に変換するのではなく、磁気媒体
上の磁化パターンを光磁気効果膜に転写し、これをレー
ザビームで走査して、光磁気効果により、転写された磁
気パターンの強度に応じてレーザビームを変調させ、こ
の変調された光ビームを検出して記録情報を再生するも
のである。Therefore, in order to solve such a problem, a method has been proposed in which information recorded at a high density is reproduced by utilizing the magneto-optical effect (Study of Technical Report Vol.1 No.42 1979.5 pp.
21-28 "A study on magneto-optical recording method" by Tatsuo Nomura et al.). This does not directly convert the magnetic flux change due to the magnetization of the magnetic medium into an electric signal by the winding, but transfers the magnetization pattern on the magnetic medium to the magneto-optical effect film, scans this with a laser beam, Due to the magneto-optical effect, the laser beam is modulated according to the intensity of the transferred magnetic pattern, and the modulated light beam is detected to reproduce the recorded information.
しかし、かかる従来の方式によると、レーザビームのス
ポツト径よりも短かい記録波長の信号成分は再生され得
ず、広帯域のビデオ信号の再生においては、周波数帯域
が制限されてしまう。また、トラツクの幅を狭くして高
密度記録した場合にS/Nを向上させるためには、光磁気
効果膜に転写された磁気パターンの強度が高くなければ
ならず、このためには、光磁気効果膜を厚くして磁気媒
体からの磁気パターンの転写を充分に行なえばよいが、
このようにすると、光磁気効果膜への磁気パターンの転
写性が劣化する。However, according to such a conventional method, a signal component having a recording wavelength shorter than the spot diameter of the laser beam cannot be reproduced, and the frequency band is limited in reproducing a wideband video signal. Further, in order to improve the S / N when the track width is narrowed and high density recording is performed, the strength of the magnetic pattern transferred to the magneto-optical effect film must be high. It is sufficient to thicken the magnetic effect film to sufficiently transfer the magnetic pattern from the magnetic medium.
If so, the transferability of the magnetic pattern to the magneto-optical effect film deteriorates.
以上のように、従来では、高密度記録化をはかると、高
周波化やS/Nの向上が望めないという問題があつた。As described above, in the past, there has been a problem that it is impossible to expect higher frequencies and improved S / N when high density recording is attempted.
本発明の目的は、かかる問題点を解消し、高周波化やS/
Nの向上を伴なう高記録密度化を実現可能とした光磁気
型再生磁気ヘツドを提供するにある。The object of the present invention is to eliminate such problems, to achieve higher frequencies and S / S.
It is to provide a magneto-optical reproducing magnetic head capable of realizing a high recording density accompanied by an improvement in N.
この目的を達成するために、本発明は、ヘツドチツプ部
材の磁路中にフアラデー効果を生ずる磁性膜を設けると
ともに、該磁性膜に編光した光ビームを入射させ、該磁
性膜を通つた光ビームを検光子を介して受光素子に受光
させる。In order to achieve this object, the present invention provides a magnetic film that produces a Faraday effect in the magnetic path of a head chip member, and allows a light beam that has been knitted into the magnetic film to be incident on the magnetic film. Is received by the light receiving element via the analyzer.
該光ビームの偏光面は、該磁性膜の磁化の向きに応じた
方向にフアラデー回転し、これにより、検光子を通して
受光素子で受光される光量、したがつて、受光素子から
出力される電気信号のレベルは該磁性層の磁化の向きに
応じて変化する。The plane of polarization of the light beam rotates Faraday in the direction according to the direction of magnetization of the magnetic film, whereby the amount of light received by the light receiving element through the analyzer, and thus the electrical signal output from the light receiving element. Level changes depending on the direction of magnetization of the magnetic layer.
以下、本発明の実施例を図面によつて説明する。 Embodiments of the present invention will be described below with reference to the drawings.
第１図は本発明による光磁気型再生磁気ヘツドの一実施
例の全体構成を示す斜視図であつて、１は下部磁性コ
ア、２は光反射膜、３は磁性膜、４はヘツドギヤツプ
膜、５は非磁性膜、６は上部磁性コア、７は磁気ギヤツ
プ、８は入射穴、９はレーザビーム、10はレーザ源、11
は受光素子、12はハーフミラー、13は検光子、14はテー
プ摺動面である。FIG. 1 is a perspective view showing the overall construction of an embodiment of a magneto-optical reproducing magnetic head according to the present invention, in which 1 is a lower magnetic core, 2 is a light reflecting film, 3 is a magnetic film, 4 is a headgear film, 5 is a non-magnetic film, 6 is an upper magnetic core, 7 is a magnetic gear, 8 is an entrance hole, 9 is a laser beam, 10 is a laser source, 11
Is a light receiving element, 12 is a half mirror, 13 is an analyzer, and 14 is a tape sliding surface.
この実施例は、磁気チツプ部材と光学系とからなるが、
まず、磁気チツプ部材の構成について説明する。This embodiment consists of a magnetic chip member and an optical system,
First, the structure of the magnetic chip member will be described.
同図において、下部磁性コア１はフエライトからなつて
基板としての機能も有しており、その全面には光反射膜
２が設けられている。この光反射膜２はCrなどの金属が
蒸着法あるいはスパツタ法によつて形成されたものであ
り、厚さは500Å〜1000Åに設定される。この光反射膜
２上の所定の位置に大きなフアラデー効果を生ずる磁性
ガーネツトなどからなる磁性膜３が設けられている。こ
の磁性膜３はフオトリゾグラフツク技術によつて所定形
状にパターニングされて形成され、その膜厚は３〜20μ
ｍに設定されている。光反射膜２および磁気膜３の一部
にまたがつてヘツドギヤツプ膜４が設けられ、そのヘツ
ドギヤツプ膜４の一部に、一部が磁性膜３上にあるよう
に、非磁性膜５が設けられている。そして、さらに、ヘ
ツドギヤツプ膜４、非磁性膜５および磁性膜３にまたが
るように、上部磁性コア６が設けられている。ヘツドギ
ヤツプ膜４は、Crの膜を被着形成後、パターニングによ
つて所定形状に形成されたものであり、その膜厚は0.3
μｍ程度に設定されている。被磁性膜５は、SiO2の膜を
被着形成後、パターニングによつて所定形状に形成され
たものであり、SiO2などを材料として膜厚は10〜20μｍ
に設定されている。上部コア磁性膜６は、センダスト、
Fe−Ni,Co−Nd,Zr非晶質磁性膜などを被着形成後、パタ
ーニングによつて所定形状に形成されたものである。In the figure, the lower magnetic core 1 is made of ferrite and also has a function as a substrate, and a light reflection film 2 is provided on the entire surface thereof. The light reflecting film 2 is made of a metal such as Cr formed by a vapor deposition method or a sputtering method, and has a thickness of 500Å to 1000Å. At a predetermined position on the light reflection film 2, a magnetic film 3 made of a magnetic garnet or the like that produces a large Faraday effect is provided. This magnetic film 3 is formed by patterning into a predetermined shape by a photolithographic technique, and its film thickness is 3 to 20 μm.
It is set to m. A headgear film 4 is provided over a part of the light reflection film 2 and the magnetic film 3, and a nonmagnetic film 5 is provided on a part of the headgap film 4 so that a part thereof is on the magnetic film 3. ing. Further, an upper magnetic core 6 is provided so as to straddle the headgear film 4, the non-magnetic film 5 and the magnetic film 3. The headgear film 4 is formed in a predetermined shape by patterning after depositing a Cr film and has a film thickness of 0.3.
It is set to about μm. The magnetic film 5 is formed into a predetermined shape by depositing a SiO 2 film and then patterning it. The film thickness is 10 to 20 μm using SiO 2 as a material.
Is set to. The upper core magnetic film 6 is a sendust,
An Fe—Ni, Co—Nd, Zr amorphous magnetic film or the like is deposited and formed into a predetermined shape by patterning.
かかる構成において、各部磁性コア１、磁性膜３、上部
磁性コア６によつて磁路が形成されており、テープ摺動
面14側では、各部磁性コア１と上部磁性コア６とがヘツ
ドギヤツプ膜４を介して対向し、テープ摺動面14では、
このヘツドギャツプ膜４によつて上部磁性コア１、上部
磁性コア６間が磁気ギヤツプ７をなしている。また、被
磁性膜５は上部磁性コア６の一部を下部磁性コア１およ
び磁性膜３から充分離し、磁路からの磁束の漏洩を防止
するものである。In this structure, a magnetic path is formed by the magnetic cores 1, magnetic films 3, and upper magnetic cores 6, and the magnetic cores 1 and the upper magnetic cores 6 are formed on the tape sliding surface 14 side. , And the tape sliding surface 14
The head gap film 4 forms a magnetic gap 7 between the upper magnetic core 1 and the upper magnetic core 6. Further, the magnetic film 5 is for separating a part of the upper magnetic core 6 from the lower magnetic core 1 and the magnetic film 3 to prevent leakage of magnetic flux from the magnetic path.
上部磁性コア６の磁性膜３に重なった部分（以下、リア
部トイウ）には、磁性膜３に達する入射穴８が設けられ
ている。An incident hole 8 reaching the magnetic film 3 is provided in a portion of the upper magnetic core 6 that overlaps with the magnetic film 3 (hereinafter referred to as rear portion).
以上が磁気チップ部材の構成の説明であるが、次に、光
学系について説明する。The above is the description of the configuration of the magnetic chip member. Next, the optical system will be described.
この光学系は、レーザ源10、受光素子11、ハーフミラー
12および検光子13からなつている。This optical system includes a laser source 10, a light receiving element 11, and a half mirror.
It consists of 12 and an analyzer 13.
レーザ源10からは偏光したレーザビーム９が出力され
る。これは、ハーフミラー12を通り、入射穴８から磁性
膜３に入射する。このレーザビーム９は、磁性膜３を通
つて光反射膜２で反射され、再び磁性膜３、入射穴８を
通つた後、ハーフミラー12で反射されて検光子13を通
り、受光素子11で受光される。A polarized laser beam 9 is output from the laser source 10. This passes through the half mirror 12 and enters the magnetic film 3 through the entrance hole 8. The laser beam 9 passes through the magnetic film 3, is reflected by the light reflecting film 2, passes through the magnetic film 3 and the incident hole 8 again, is reflected by the half mirror 12, passes through the analyzer 13, and is received by the light receiving element 11. Received light.
第２図は第１図のＡ−Ａ′に沿う断面図であつて、15は
磁気テープであり、第１図に対応する部分には同一符号
をつけている。FIG. 2 is a sectional view taken along the line AA 'in FIG. 1, in which reference numeral 15 is a magnetic tape, and the portions corresponding to those in FIG.
第２図において、磁気テープ15がテープ摺動面に沿つて
走行しているとすると、この磁気テープ15の磁化による
磁束が下部磁性コスト１、磁性膜３、上部磁性コア６を
介して流れ、磁性膜３はその厚さ方向に磁化される。一
方、レーザ源10からの偏光されたレーザビーム９は、入
射穴８を通つて磁性膜３にその厚み方向（すなわち、磁
性膜３の磁化方向に平行な方向）に入射され、また、光
反射膜２で反射されて再び磁性膜３の厚み方向に進む。
この磁性膜３を通るとき、偏光されたレーザビーム９の
偏光面は、フアラデー効果により、磁性膜３の磁化の向
きに応じて互いに反対の方向に回転する。In FIG. 2, assuming that the magnetic tape 15 is running along the sliding surface of the tape, the magnetic flux due to the magnetization of the magnetic tape 15 flows through the lower magnetic cost 1, the magnetic film 3, and the upper magnetic core 6, The magnetic film 3 is magnetized in its thickness direction. On the other hand, the polarized laser beam 9 from the laser source 10 is incident on the magnetic film 3 through the entrance hole 8 in the thickness direction thereof (that is, in the direction parallel to the magnetization direction of the magnetic film 3), and the light reflection It is reflected by the film 2 and proceeds again in the thickness direction of the magnetic film 3.
When passing through the magnetic film 3, the polarization planes of the polarized laser beam 9 rotate in opposite directions depending on the magnetization direction of the magnetic film 3 due to the Faraday effect.
いま、磁性膜３が下部磁性コア１側から上部磁性コア６
側に磁束が通るように磁化されているものとすると、レ
ーザ源10から入射穴８を通して磁性膜３に入射されるレ
ーザビームが、下部磁性コア１側からレーザビーム９の
入射部分を見た第３図（ａ）において、矢印L1方向に偏
光されているとすると、磁性膜３の磁化によつて矢印L2
方向にΔθだけ偏光面が回転する。次に、光反射膜２に
おけるレーザビーム９の偏光面は、入射穴８側から磁性
膜３方向をみると、第３図（ｂ）に示すように、矢印L1
で示す入射前のレーザビーム９の偏光面の方向に対し
て、第３図（ａ）の場合とは逆方向にΔθだけずれた矢
印L2′で表わされる。この反射されたレーザビーム９の
進行方向と磁性膜３の磁化方向の向きとの関係は、レー
ザビーム９が入射される場合とは逆になるから、この反
射レーザビーム９の偏光面は、矢印L2′からさらに第３
図（ａ）の場合とは逆方向にΔθだけ回転し（下部磁性
コア１側からみると、第３図（ａ）の場合と回転方向が
同じである）、矢印L3で表わされる。Now, the magnetic film 3 is arranged from the lower magnetic core 1 side to the upper magnetic core 6 side.
Assuming that the laser beam is magnetized so that the magnetic flux passes through the side, the laser beam incident on the magnetic film 3 from the laser source 10 through the incident hole 8 is the first part when the laser beam 9 is seen from the lower magnetic core 1 side. In FIG. 3 (a), if polarized in the direction of the arrow L 1 , the magnetization of the magnetic film 3 causes the arrow L 2
The plane of polarization rotates by Δθ in the direction. Then, the plane of polarization of the laser beam 9 in the light reflection layer 2, looking at the magnetic film 3 direction from the entrance hole 8 side, as shown in FIG. 3 (b), an arrow L 1
The arrow L 2 ′ is shifted from the direction of the plane of polarization of the laser beam 9 before incidence by Δθ in the opposite direction to the case of FIG. 3 (a). Since the relationship between the traveling direction of the reflected laser beam 9 and the direction of the magnetization direction of the magnetic film 3 is opposite to that when the laser beam 9 is incident, the polarization plane of the reflected laser beam 9 is indicated by an arrow. Third from L 2 ′
It is rotated by Δθ in the opposite direction to the case of FIG. 3A (the rotation direction is the same as in the case of FIG. 3A when viewed from the lower magnetic core 1 side), and is represented by an arrow L 3 .
この結果、レーザビーム９の偏光面は、磁性膜３に入射
し、光反射膜２で反射されて磁性膜３から出射するまで
に２Δθだけ回転する。磁性膜３の磁化の向きが上記と
は逆の場合には、レーザビーム９の偏光面の回転は、上
記の場合と大きさが等しく方向が逆になる。したがつ
て、２Δθをθｆとすると、磁性膜３の磁化の向きに応
じてレーザビーム９の偏光面は＋θｆあるいは−θｆだ
け回転することになる。As a result, the plane of polarization of the laser beam 9 is rotated by 2Δθ before entering the magnetic film 3, being reflected by the light reflecting film 2 and being emitted from the magnetic film 3. When the magnetization direction of the magnetic film 3 is opposite to the above, the rotation of the polarization plane of the laser beam 9 has the same magnitude and opposite direction as in the above case. Therefore, if 2Δθ is θ f , the polarization plane of the laser beam 9 rotates by + θ f or −θ f depending on the direction of magnetization of the magnetic film 3.
そこで、第４図において、検光子13の偏向軸（偏光の透
過方向）をＡ軸方向とすると、レーザ源10からのレーザ
ビーム９の偏光面の方向はこのＡ方向よりも45°ずれた
Ｂ軸方向に設定する。このＢ方向のベクトルＢとし、こ
れがレーザ源10からのレーザビーム９とする。いま、磁
性膜３が上部磁性コア６方向に磁束が通るように磁化さ
れているとき、入射穴８を通して磁性膜３から出射され
たレーザビーム９が、ベクトルで示すように、Ｂ軸か
ら＋θｆだけ偏光面が回転したものとなつているとする
と、検光子13ではこのレーザビーム９のうちのＡ軸方向
の成分のみしか通過せず、受光素子11ではベクトルで
表わすレーザビームが受光される。このレーザビームの
光量｜｜は、 ｜｜＝｜|cos（45°＋θｆ） ＝｜|cos（45°＋θｆ） となる。磁性膜３が下部磁性コア方向に磁束が通るよう
に磁化されたときには、入射穴８を通して磁性膜３から
出射されるレーザビーム９は、ベクトル′で示すよう
に、Ｂ軸から−θｆだけ偏光面が回転したものとなる。
したがつて、この場合の検光子13を通して受光素子11に
受光されるレーザビームはベクトルＡ′で表わされ、そ
の受光量｜′｜は、 ｜′｜＝｜′|cos（45°−θｆ） ＝｜|cos（45°−θｆ） となる。Therefore, in FIG. 4, assuming that the deflection axis of the analyzer 13 (the transmission direction of polarized light) is the A-axis direction, the direction of the polarization plane of the laser beam 9 from the laser source 10 is shifted by 45 ° from the A direction. Set in the axial direction. This vector B in the B direction is used as the laser beam 9 from the laser source 10. Now, when the magnetic film 3 is magnetized so that a magnetic flux passes in the direction of the upper magnetic core 6, the laser beam 9 emitted from the magnetic film 3 through the entrance hole 8 is + θ f from the B axis as indicated by the vector. Assuming that the plane of polarization is rotated only by that amount, the analyzer 13 can pass only the component of the laser beam 9 in the A-axis direction, and the light receiving element 11 receives the laser beam represented by the vector. The light quantity || of the laser beam is || = || cos (45 ° + θ f ) = || cos (45 ° + θ f ). When the magnetic film 3 is magnetized so that a magnetic flux passes in the direction of the lower magnetic core, the laser beam 9 emitted from the magnetic film 3 through the entrance hole 8 is polarized by −θ f from the B axis as indicated by the vector '. The surface is rotated.
Therefore, the laser beam received by the light receiving element 11 through the analyzer 13 in this case is represented by the vector A ', and the received light amount |' | is given by | '| = |' | cos (45 ° -θ f ) = || cos (45 ° −θ f ).
以上のようにして、磁性膜３の磁化に向きによつて受光
素子11での受光量が異なり、また、磁気テープ15には、
FM変調されて信号が記録されており、これによる磁気パ
ターンに応じて磁性膜３の磁化の向きが変化するから、
受光素子11から磁気テープ15に記録されている信号が得
られる。As described above, the amount of light received by the light receiving element 11 varies depending on the direction of magnetization of the magnetic film 3, and the magnetic tape 15 has
A signal is recorded by being FM-modulated, and the direction of magnetization of the magnetic film 3 changes according to the magnetic pattern resulting from this,
The signal recorded on the magnetic tape 15 is obtained from the light receiving element 11.
次の表１は、磁気テープをメタル微粉テープとし、ヘツ
ド・テープ間相対速度を3.8m/sec、キヤリア周波数5MHz
としたときの、上記実施例、従来の巻線型薄膜ヘツド、
従来の磁気抵抗効果型（MR）再生ヘツドのC/Namp,C/N
totaLを比較して示したものである。The following Table 1 shows the magnetic tape as fine metal powder tape, the relative speed between the head and tape is 3.8 m / sec, and the carrier frequency is 5 MHz.
In the above example, the conventional wire wound thin film head,
Conventional magnetoresistive (MR) playback head C / N amp , C / N
It is shown by comparing totaL .
なお、Ｃはキヤリア出力、Nampはシステムで生ずるノイ
ズ、NtotaLは磁気テープとヘツドとに生ずるノイズであ
る。 C is carrier output, N amp is noise generated in the system, and N tota L is noise generated in the magnetic tape and the head.
表１から明らかなように、上記実施例では、他の従来ヘ
ツドに比べ、C/NtotaLは大差ないが、C/Nampが19〜20dB
優れている。このことから、C/NtotaLはほとんど磁気媒
体に生ずるノイズによつて決まることがわかり、また、
上記実施例では、他の従来ヘツドに比べて再生出力が大
きいことがわかる。As is clear from Table 1, in the above-mentioned embodiment, C / N totaL is not much different from other conventional heads, but C / N amp is 19 to 20 dB.
Are better. From this, it can be seen that C / N totaL is mostly determined by the noise generated in the magnetic medium, and
It can be seen that in the above embodiment, the reproduction output is larger than that of other conventional heads.
また、ヘツド・テープ間相対速度を4.75cm/secの低速と
した場合と24m/secの高速とした場合のC/Nを測定したと
ころ、上記実施例では、C/Nがほとんど変わらなかつた
が、巻線型磁気ヘツドでは、低速時再生不能であり、高
速時でヘツドのインダクタンスによつて再生出力が低下
し、したがつて、C/Nが低下した。Further, when the relative speed between the head and tape was set to a low speed of 4.75 cm / sec and the high speed of 24 m / sec was measured, the C / N was measured. , The winding type magnetic head cannot reproduce at low speed, and at high speed, the reproduction output decreased due to the inductance of the head, and thus the C / N decreased.
以上のことから、上記実施例を用いた場合には、磁気テ
ープの走行速度を遅くしてトラツクの幅を狭くすること
により、多少再生出力を低下させても、充分高いC/Nが
得られ、したがつて、従来のヘツドを用いた場合に比べ
てより高密度記録化が促進できることになる。From the above, in the case of using the above embodiment, a sufficiently high C / N can be obtained even if the reproduction output is slightly lowered by slowing the running speed of the magnetic tape and narrowing the width of the track. Therefore, higher density recording can be promoted as compared with the case of using the conventional head.
ところで、この実施例においては、第５図に示すよう
に、リア部での上部磁性コア６の磁性膜３が接する部分
16の面積S1を小さくし、上部磁性コア６のフロントギヤ
ツプ部17での面積S2に対し、S1＜S2とする。これによ
り、上部磁性コア６を通る磁束はしぼられて磁性膜３に
入り込むために、磁性膜３のレーザビーム９（第１図）
が入射される部分の磁化が強くなり、レーザビーム９の
フアラデー回転が大となつて感度、C/Nがさらに向上す
る。By the way, in this embodiment, as shown in FIG. 5, the portion of the upper magnetic core 6 in the rear portion where the magnetic film 3 contacts.
The area S 1 of 16 is reduced so that S 1 <S 2 with respect to the area S 2 at the front gear tap portion 17 of the upper magnetic core 6. As a result, the magnetic flux passing through the upper magnetic core 6 is squeezed and enters the magnetic film 3, so that the laser beam 9 on the magnetic film 3 (FIG. 1).
The magnetization of the portion where is injected becomes strong, the Faraday rotation of the laser beam 9 becomes large, and the sensitivity and C / N are further improved.
ただし、この部分16の面積S1を極端に小さくすると、こ
の部分16での磁気抵抗が増大して磁束が減ずるので、逆
に感度、C/Nが低下することは従来の磁気ヘツドと同様
である。磁性膜３の材料としてガーネツトを用いると、
その比透磁率は数百であるので、部分16の面積S1を適度
に小さくして感度、C/Nを高めることは可能である。However, if the area S 1 of this portion 16 is made extremely small, the magnetic resistance in this portion 16 increases and the magnetic flux decreases, so conversely, the sensitivity and C / N decrease as in the conventional magnetic head. is there. If garnet is used as the material of the magnetic film 3,
Since its relative magnetic permeability is several hundreds, it is possible to increase the sensitivity and C / N by appropriately reducing the area S 1 of the portion 16.
第６図は本発明による光磁気型再生磁気ヘツドの他の実
施例を示す断面図であつて、９′は光、18は反射防止膜
であり、第１図に対応する部分には同一符号をつけて重
複する説明は省略する。FIG. 6 is a cross-sectional view showing another embodiment of the magneto-optical reproducing magnetic head according to the present invention, in which 9'is light and 18 is an antireflection film, and the same symbols are given to the portions corresponding to FIG. And redundant description will be omitted.
第６図において、上部磁性コア６上の入射穴８の周囲に
反射防止膜18が設けられている。これにより、入射穴８
に入り込まない光９′は反射防止され、ハーフミラー12
を介して検光子13（第１図）に入射しないようにしてい
る。In FIG. 6, an antireflection film 18 is provided around the entrance hole 8 on the upper magnetic core 6. This allows the entrance hole 8
The light 9'that does not enter is prevented from being reflected, and the half mirror 12
The light is prevented from entering the analyzer 13 (FIG. 1) via the.
そこで、レーザ源10（第１図）からのレーザビーム９が
入射穴８からずれたり、そのビーム径が入射穴８の径よ
りも大きくても、検光子13には、磁性膜３によつてフア
ラデー回転を受けた光のみが入射され、C/Nの劣化を防
止できるとともに、光学系の設定許容範囲を大きくとれ
る。Therefore, even if the laser beam 9 from the laser source 10 (FIG. 1) is displaced from the entrance hole 8 or the beam diameter thereof is larger than the diameter of the entrance hole 8, the analyzer 13 is caused by the magnetic film 3. Only the light that has undergone the Faraday rotation is incident, preventing C / N from deteriorating and increasing the allowable setting range of the optical system.
なお、反射防止膜18には、光吸収体、表面を粗くした光
散乱体、1/2波長の光干渉を利用して反射光を防止する
薄膜などを用いることができる。As the antireflection film 18, a light absorber, a light scatterer having a roughened surface, a thin film that prevents reflected light by utilizing 1/2 wavelength light interference, or the like can be used.
第７図は本発明による光磁気型再生磁気ヘツドのさらに
他の実施例を示す断面図であつて、19は非磁性基板であ
り、第６図に対応する部分には同一符号をつけて重複す
る説明を省略する。FIG. 7 is a cross-sectional view showing still another embodiment of the magneto-optical reproducing magnetic head according to the present invention, in which 19 is a non-magnetic substrate, and the portions corresponding to those in FIG. The description will be omitted.
先の実施例においては、下部磁性コア１をフエライト磁
性基板としたが、第７図に示すこの実施例では、下部磁
性コア１をガラスなどの非磁性基板19に積層された磁性
膜とするものである。この下部磁性コア１としては、フ
エライトに比べて比透磁率μが大きいセンダスト、Fe−
Ni,Co−Nd−Zr系の非晶質磁性膜とすることができ、よ
り感度が向上する。In the previous embodiment, the lower magnetic core 1 was a ferrite magnetic substrate, but in this embodiment shown in FIG. 7, the lower magnetic core 1 is a magnetic film laminated on a non-magnetic substrate 19 such as glass. Is. The lower magnetic core 1 is made of sendust, Fe-, which has a relative magnetic permeability μ larger than that of ferrite.
A Ni, Co-Nd-Zr-based amorphous magnetic film can be formed, and the sensitivity is further improved.
なお、この実施例では、第１図や第６図に示した実施例
におけるような光反射膜２を設ける必要はない。また、
第１図に示した実施例においても、第７図に示した実施
例のように、下部磁性コア１として、フエライト磁性基
板の代りに、非磁性基板19に積層した磁性膜とすること
ができる。In this embodiment, it is not necessary to provide the light reflecting film 2 as in the embodiment shown in FIGS. Also,
Also in the embodiment shown in FIG. 1, as in the embodiment shown in FIG. 7, the lower magnetic core 1 may be a magnetic film laminated on the non-magnetic substrate 19 instead of the ferrite magnetic substrate. .
第８図は本発明による光磁気型再生磁気ヘツドのさらに
他の実施例を示す断面図であつて、20は貫通穴であり、
前出の図面に対応する部分には同一符号をつけて重複す
る説明は省略する。FIG. 8 is a sectional view showing still another embodiment of the magneto-optical reproducing magnetic head according to the present invention, in which 20 is a through hole,
The parts corresponding to those in the above drawings are designated by the same reference numerals, and the duplicated description will be omitted.
第１図、第６図および第７図に示した実施例はレーザビ
ーム９が光反射膜２あるいは下部磁性コア１で反射され
る反射型のものであつたが、第８図に示す実施例は透過
型のものである。The embodiment shown in FIGS. 1, 6 and 7 is a reflection type in which the laser beam 9 is reflected by the light reflecting film 2 or the lower magnetic core 1, but the embodiment shown in FIG. Is a transmissive type.
すなわち、第８図において、第７図に示した実施例と同
様に、ガラスなどの透明な非磁性基板19上に磁性膜の下
部磁性コア１が設けられ、この下部磁性コア１が上部磁
性コア６、磁性膜３とともに磁路を形成するが、ここ
で、下部磁性コア１に入射穴８と同軸となり、これと同
径の貫通穴20を設けている。That is, in FIG. 8, as in the embodiment shown in FIG. 7, a lower magnetic core 1 of a magnetic film is provided on a transparent non-magnetic substrate 19 such as glass, and the lower magnetic core 1 is an upper magnetic core. 6. A magnetic path is formed with the magnetic film 3. Here, the lower magnetic core 1 is provided with a through hole 20 coaxial with the incident hole 8 and having the same diameter as the incident hole 8.
上部磁性コア６側に配置されたレーザ源10からのレーザ
ビーム９は、入射穴８から磁性膜３に入り込み、そこで
フアラデー回転した後、貫通穴20、光透過性非磁性基板
19を通り、さらに、この基板19側に配置された検光子13
を通つて受光素子11に受光される。A laser beam 9 from a laser source 10 arranged on the side of the upper magnetic core 6 enters the magnetic film 3 through an entrance hole 8 and rotates Faraday there, and then a through hole 20 and a light transmissive non-magnetic substrate.
After passing through 19, the analyzer 13 placed on the side of the substrate 19
The light is received by the light receiving element 11 through the light.
この実施例によると、第１図、第６図、第７図の実施例
よりもハーフミラー12が不要となつて光学系が簡略化
し、さらに、レーザ源10、検光子13、受光素子11が直線
上に配置されるから、位置決め精度を大幅に緩和でき
る。According to this embodiment, the optical system is simplified by eliminating the need for the half mirror 12 as compared with the embodiments of FIGS. 1, 6 and 7, and further, the laser source 10, the analyzer 13 and the light receiving element 11 are Since they are arranged on a straight line, the positioning accuracy can be greatly eased.
以上説明したように、本発明によれば、従来技術に比べ
て非常に高い感度とC/Nとが得られ、磁気媒体上のトラ
ツクの幅を狭くしても良好なC/Nが得られて高密度記録
がより促進され、かつ、磁気的な信号を電気的な信号に
変換する手段に周波数帯域を制限する部材が含まれない
ために、広帯域信号の再生が可能となつて高周波化もよ
り促進されるし、さらに、入射穴に対する光ビームのず
れがあったり、光ビームの径が入射穴の径よりも大きく
ても、ファラデー効果を生ずる磁性膜以外の部分で反射
された光ビームが受光素子で受光されるのを防止するこ
とができるから、光学系の設定許容範囲が緩和される。As described above, according to the present invention, much higher sensitivity and C / N can be obtained as compared with the prior art, and good C / N can be obtained even if the track width on the magnetic medium is narrowed. High-density recording is further promoted, and the means for converting a magnetic signal into an electric signal does not include a member for limiting the frequency band. Therefore, it is possible to reproduce a wideband signal and also to increase the frequency. Even if there is a deviation of the light beam with respect to the entrance hole or the diameter of the light beam is larger than the diameter of the entrance hole, the light beam reflected by a portion other than the magnetic film that causes the Faraday effect will be Since it is possible to prevent the light receiving element from receiving light, the allowable setting range of the optical system is relaxed.
【図面の簡単な説明】 第１図は本発明による光磁気型再生磁気ヘツドの一実施
例の全体構成を示す斜視図、第２図は第１図のＡ−Ａ′
に沿う断面図、第３図は第１図におけるフアラデー効果
を生ずる磁性膜の作用を示した説明図、第４図は第１図
の実施例の再生動作を説明するためのベクトル図、第５
図はその実施例の要部を示した上面図、第６図〜第８図
は夫々本発明による光磁気型再生磁気ヘツドの他の実施
例を示す断面図である。 １……下部磁性コア、２……光反射膜、３……フアラデ
ー効果を生ずる磁性膜、６……上部磁性コア、７……磁
気ギヤツプ、８……入射穴、９……レーザビーム、10…
…レーザ源、11……受光素子、13……検光子、14……テ
ープ摺動面、15……リア部での上部磁性コアの磁性膜と
接する部分、17……上部磁性コアのフロントギャップ
部、18……反射防止膜、19……非磁性基板、20……貫通
穴。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing the overall construction of an embodiment of a magneto-optical reproducing magnetic head according to the present invention, and FIG. 2 is an AA 'in FIG.
3 is a sectional view taken along line 3, FIG. 3 is an explanatory view showing the action of the magnetic film producing the Faraday effect in FIG. 1, FIG. 4 is a vector diagram for explaining the reproducing operation of the embodiment of FIG. 1, and FIG.
FIG. 6 is a top view showing a main part of the embodiment, and FIGS. 6 to 8 are sectional views showing other embodiments of the magneto-optical reproducing magnetic head according to the present invention. 1 ... Lower magnetic core, 2 ... Light-reflecting film, 3 ... Magnetic film that produces Faraday effect, 6 ... Upper magnetic core, 7 ... Magnetic gap, 8 ... Incident hole, 9 ... Laser beam, 10 …
… Laser source, 11 …… Light receiving element, 13 …… Analyzer, 14 …… Tape sliding surface, 15 …… The portion of the rear part in contact with the magnetic film of the upper magnetic core, 17 …… Front gap of the upper magnetic core Part, 18 ... Antireflection film, 19 ... Non-magnetic substrate, 20 ... Through hole.
Claims (2)
磁性コアとがヘッドギャップ膜を挟んで磁気ギャップが
形成され、該テープ摺動面側とは反対側のリア部では該
上部磁性コアと該下部磁性コアとの間にファラデー効果
を生ずる磁性膜が設けられ、該リア部で該上部磁性コア
に該磁性膜まで達する入射穴が設けられたチップ部材
と、 偏光した光ビームを出力する光源、検光子および受光素
子と からなり、 該上部磁性コアでの該入射穴が設けられて該磁性膜に重
なる部分の面積S1をフロントギャップ部での該上部磁性
コアの面積S2よりも小さくし、 該光源からの光ビームを該入射穴から該磁性膜に入射
し、該磁性膜でファラデー回転した光ビームを該検光子
を介して該受光素子で受光するように構成したことを特
徴とする光磁気型再生磁気ヘツド。1. A magnetic gap is formed between an upper magnetic core and a lower magnetic core on a tape sliding surface side with a head gap film sandwiched therebetween, and the upper magnetic core is formed at a rear portion opposite to the tape sliding surface side. A magnetic film is provided between the core and the lower magnetic core to produce a Faraday effect, and a chip member is provided with an entrance hole reaching the magnetic film in the upper magnetic core at the rear portion, and a polarized light beam is output. Which is composed of a light source, an analyzer and a light receiving element, and the area S 1 of the portion of the upper magnetic core which is provided with the entrance hole and overlaps the magnetic film is smaller than the area S 2 of the upper magnetic core in the front gap portion. The light beam from the light source is made incident on the magnetic film through the incident hole, and the light beam Faraday-rotated by the magnetic film is received by the light receiving element through the analyzer. Characteristic magneto-optical reproducing magnetism Ki head.
性コアとがヘッドギャップ膜を挟んで磁気ギャップが形
成され、該テープ摺動面側とは反対側のリア部では、該
上部磁性コアと該下部磁性コアとの間に、ファラデー効
果を生ずる磁性膜が設けられて該磁性膜は該下部磁性コ
ア側に光反射膜を有し、該リア部で該上部磁性コアに該
磁性膜まで達する入射穴が設けられたチップ部材と、 偏光した光ビームを出力する光源、検光子および受光素
子と からなり、 該上部磁性コア上の少なくとも該入射穴の周りに反射防
止膜が設けられ、 該光源からの光ビームを該入射穴から該磁性膜に入射
し、該磁性膜でファラデー回転した光ビームを該検光子
を介して該受光素子で受光するように構成したことを特
徴とする光磁気型再生磁気ヘツド。2. A magnetic gap is formed on the tape sliding surface side with an upper magnetic core and a lower magnetic core sandwiching a head gap film, and the upper magnetic core is formed on a rear portion opposite to the tape sliding surface side. A magnetic film that produces a Faraday effect is provided between the core and the lower magnetic core, the magnetic film has a light reflecting film on the lower magnetic core side, and the magnetic film is provided on the upper magnetic core at the rear portion. A chip member having an entrance hole reaching up to, a light source for outputting a polarized light beam, an analyzer and a light receiving element, and an antireflection film provided at least around the entrance hole on the upper magnetic core, A light beam which is configured such that a light beam from the light source is incident on the magnetic film through the entrance hole, and a Faraday-rotated light beam in the magnetic film is received by the light receiving element through the analyzer. Magnetic reproduction magnetic head.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61026951A JPH071561B2 (en) | 1986-02-12 | 1986-02-12 | Magneto-optical reproducing magnetic head |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61026951A JPH071561B2 (en) | 1986-02-12 | 1986-02-12 | Magneto-optical reproducing magnetic head |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62185267A JPS62185267A (en) | 1987-08-13 |
| JPH071561B2 true JPH071561B2 (en) | 1995-01-11 |
Family
ID=12207460
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61026951A Expired - Lifetime JPH071561B2 (en) | 1986-02-12 | 1986-02-12 | Magneto-optical reproducing magnetic head |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH071561B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2652670B1 (en) * | 1989-10-03 | 1995-06-23 | Thomson Csf | HIGH RESOLUTION MAGNETOOPTIC READING HEAD. |
| FR2656723B1 (en) * | 1989-12-28 | 1995-07-21 | Thomson Consumer Electronics | MAGNETO-OPTICAL MULTI-TRACK READING HEAD. |
| JP4957154B2 (en) * | 2006-09-29 | 2012-06-20 | ダイキン工業株式会社 | Packing material for air conditioner |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57183646A (en) * | 1981-05-07 | 1982-11-12 | Nec Corp | Magnetic recorder and reproducer |
| JPS6139956A (en) * | 1984-07-31 | 1986-02-26 | Nippon Hoso Kyokai <Nhk> | Magnetooptic head |
-
1986
- 1986-02-12 JP JP61026951A patent/JPH071561B2/en not_active Expired - Lifetime
Non-Patent Citations (1)
| Title |
|---|
| ＩＢＭＴｅｃｈｎｉｃａｌＤｉｓｃｌｏｓｕｒｅＢｕｌｌｅｔｉｎ，１３〔８〕（１９７１−１）Ｐ．２２７６ |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62185267A (en) | 1987-08-13 |
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