JP2676842B2 - Magneto-optical head - Google Patents
Magneto-optical headInfo
- Publication number
- JP2676842B2 JP2676842B2 JP27355888A JP27355888A JP2676842B2 JP 2676842 B2 JP2676842 B2 JP 2676842B2 JP 27355888 A JP27355888 A JP 27355888A JP 27355888 A JP27355888 A JP 27355888A JP 2676842 B2 JP2676842 B2 JP 2676842B2
- Authority
- JP
- Japan
- Prior art keywords
- magnetic field
- magneto
- field generating
- external magnetic
- objective lens
- 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 - Fee Related
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
-
- 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
- G11B11/10534—Heads for recording by magnetising, demagnetising or transfer of magnetisation, by radiation, e.g. for thermomagnetic recording
- G11B11/10536—Heads for recording by magnetising, demagnetising or transfer of magnetisation, by radiation, e.g. for thermomagnetic recording using thermic beams, e.g. lasers
Landscapes
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明は、外部磁界発生用のコイルを備え、光磁気デ
ィスクを用いて情報を記録、再生、消去する光磁気ヘッ
ドに関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical head that includes a coil for generating an external magnetic field and records, reproduces, and erases information using a magneto-optical disk.
従来の技術 近年、光磁気ディスクの開発、発表が多くの会社で行
われており、その性能、信頼性の向上が図られている。2. Description of the Related Art In recent years, many companies have been developing and presenting magneto-optical disks to improve their performance and reliability.
以下図面を参照しながら上述した従来の光磁気ヘッド
の一例について説明する。An example of the conventional magneto-optical head described above will be described below with reference to the drawings.
第３図は光磁気ディスクに情報を記録、再生、消去を
行う従来の光学系の概略を示したものである。FIG. 3 shows an outline of a conventional optical system for recording, reproducing and erasing information on a magneto-optical disk.
レーザ11から発したレーザ光はコリメートレンズ12で
略平行光になり、整形プリズム13で楕円形状のビームが
略円形に補正され、プリズム１（14）を透過し対物レン
ズ15でディスク３に集光する。The laser light emitted from the laser 11 is converted into a substantially parallel light by the collimator lens 12, the elliptical beam is corrected by the shaping prism 13 into a substantially circular shape, passes through the prism 1 (14), and is focused on the disk 3 by the objective lens 15. To do.
ディスク３で反射したビームは対物レンズ15を再度透
過後、プリズム１（14）で反射し、プリズム２（16）を
通過しレンズ20で光検出器18に集光する。その後、光検
出器18で電気信号に変換され、制御用信号が得られる。The beam reflected by the disk 3 passes through the objective lens 15 again, is reflected by the prism 1 (14), passes through the prism 2 (16), and is focused on the photodetector 18 by the lens 20. Then, it is converted into an electric signal by the photodetector 18, and a control signal is obtained.
一方、プリズム２（16）で反射したビームは波長板19
によりビームの偏波面を適当な角度に変えられ、プリズ
ム26で反射、透過し各々レンズ21,22で各々の光検出器
2,3（24,25）に集光される。各々の光検出器2,3（24,2
5）で電気信号に変換された後、差動増幅器27によりデ
ィスクに記録された信号が得られる。On the other hand, the beam reflected by the prism 2 (16) is the wave plate 19
The polarization plane of the beam can be changed to an appropriate angle by the prism 26, reflected and transmitted by the prism 26, and the lenses 21 and 22 respectively detect the respective photodetectors.
It is focused on 2,3 (24,25). Each photodetector 2,3 (24,2
After being converted into an electric signal in 5), the signal recorded on the disk is obtained by the differential amplifier 27.
また、再生時には必要はない記録、消去時にはレーザ
光の集束したディスク面に外部から磁界を加える必要が
あるため、ディスクに集束されるビームの光軸と略等し
く、かつディスクの反対側に電磁石または永久磁石（図
示では電磁石28）が配置されている。In addition, since it is necessary to apply a magnetic field from the outside to the disk surface on which the laser beam is focused during recording and erasing, which is not necessary during reproduction, it is approximately equal to the optical axis of the beam focused on the disk, and an electromagnet or A permanent magnet (electromagnet 28 in the figure) is arranged.
電磁石を用いるが、永久磁石を用いるかについてはそ
れぞれ必要に応じて使い分けられるが、実用上は、極性
の切替え時間の速さが重要視され、電磁石が用いられる
場合が多い。Although an electromagnet is used, whether to use a permanent magnet or not can be appropriately used depending on the necessity, but in practice, the speed of polarity switching time is considered important, and the electromagnet is often used.
対物レンズ15はアクチュエータに含まれるフォーカシ
ングコイル29に流す電流と該コイルに対向して配置され
た磁石の磁界との間に発生する磁気力によりディスク面
に対し垂直方向に駆動される。The objective lens 15 is driven in the direction perpendicular to the disk surface by the magnetic force generated between the current flowing through the focusing coil 29 included in the actuator and the magnetic field of the magnet arranged facing the coil.
発明が解決しようとする課題 しかしながら、上述のようにアクチュエータは駆動力
を得るため磁気力を発生しており、そのためアクチュエ
ータの外部に磁束が漏れてしまう。磁気的な遮蔽を完全
にすれば良いが重く、大きなアクチュエータになってし
まい、非現実的である。DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, as described above, the actuator generates the magnetic force to obtain the driving force, and therefore the magnetic flux leaks to the outside of the actuator. It is sufficient to completely shield magnetically, but it is heavy and becomes a large actuator, which is unrealistic.
また、洩れ磁束があれば外部磁場発生用のコイルの極
性が記録時と消去時で反転するため両者の磁気力にアン
バランスが起こる。例えば洩れ磁束が100Oeあり、外部
磁場で発生する磁界の強さがディスク面上で300Oeであ
れば記録時、消去時で両者が強め合い、弱め合うため40
0Oe、200Oeのアンバランスが生じる。外部磁場に対して
ディスクの許容幅を広げれば良いがディスクに過大な性
能を要求することになり、総合的にみて不利になる。Further, if there is a leakage magnetic flux, the polarities of the coils for generating the external magnetic field are reversed during recording and erasing, so that the magnetic forces of both are unbalanced. For example, if the leakage magnetic flux is 100 Oe and the strength of the magnetic field generated by the external magnetic field is 300 Oe on the disk surface, both will strengthen and weaken each other during recording and erasing.
An imbalance of 0 Oe and 200 Oe occurs. It is sufficient to widen the allowable width of the disk with respect to the external magnetic field, but this requires excessive performance of the disk, which is disadvantageous as a whole.
本発明は上記問題点に鑑み、アクチュエータからの洩
れ磁束があっても記録時と消去時に、反対の磁性でディ
スク面上に同じ磁界を得る装置を提供するものである。In view of the above problems, the present invention provides an apparatus for obtaining the same magnetic field on the disk surface by the opposite magnetism during recording and erasing even if there is a magnetic flux leaking from the actuator.
課題を解決するための手段 上記問題点を解決するために、本発明の光磁気ヘッド
はアクチュエータの駆動のための磁界発生用の磁石とし
て永久磁石を用いずに電磁石とし、その電磁石に流す電
流を記録時と消去時で切替え、外部磁場の外部と強めあ
う方向に合わせるようにしたものである。アクチュエー
タの駆動の方向が反転するためフォーカシングおよび、
またはトラッキング制御の極性も同時に反転させる。Means for Solving the Problems In order to solve the above problems, the magneto-optical head of the present invention is an electromagnet without using a permanent magnet as a magnet for generating a magnetic field for driving an actuator, and a current flowing through the electromagnet is used. It is switched between recording and erasing to match the direction of strengthening the external magnetic field. Focusing and because the driving direction of the actuator is reversed,
Alternatively, the polarity of tracking control is also reversed at the same time.
作用 本発明は上記した構成によりアクチュエータからの洩
れ磁束があってもディスク面上での磁束密度が記録時と
消去時でアンバランスになる事なく、逆にその洩れ磁束
を有効に利用し、外部磁場との間でプッシュプルの関係
にしてディスク面上での磁界を強め合わせ、外部磁場に
よる磁束の向きが変わっても同じ磁束密度を得ることが
できる。The present invention has the above-described structure, and even if there is a leakage magnetic flux from the actuator, the magnetic flux density on the disk surface does not become unbalanced at the time of recording and erasing, and on the contrary, the leakage magnetic flux is effectively used. It is possible to obtain the same magnetic flux density even when the direction of the magnetic flux due to the external magnetic field changes by strengthening the magnetic field on the disk surface in a push-pull relationship with the magnetic field.
実 施 例 以下、本発明の一実施例の光磁気ヘッドについて図面
を参照しながら説明する。Example Hereinafter, a magneto-optical head according to an example of the present invention will be described with reference to the drawings.
第１図は本発明にかかるアクチュエータ−ディスク外
部磁界発生コイルの関係を示した図である。ディスク３
にビームを収束させるための対物レンズ15はフォーカシ
ングコイル29の巻かれたボビン４に固定され、ディスク
に垂直方向に駆動される。FIG. 1 is a diagram showing a relationship between an actuator and a disk external magnetic field generating coil according to the present invention. Disk 3
The objective lens 15 for converging the beam is fixed to the bobbin 4 around which the focusing coil 29 is wound, and is driven in the direction perpendicular to the disc.
フォーカシングコイルに駆動力を与える磁界は鉄心１
に巻かれた磁界発生用コイル８に定電流を流すことによ
り得る。鉄心A1はベース２、対向ヨーク５に接続され磁
路を構成している。一方、ディスク３の反対側には外部
磁界発生用のコイルが鉄心B7に巻かれ、対物レンズに対
向する位置に配置されている。磁束の方向９は図示した
ようになり、コイル６と磁界発生用コイル８の間でプッ
シュプルの関係になる。The magnetic field that gives the driving force to the focusing coil is the iron core 1
It is obtained by causing a constant current to flow through the magnetic field generating coil 8 wound around. The iron core A1 is connected to the base 2 and the opposing yoke 5 to form a magnetic path. On the other hand, a coil for generating an external magnetic field is wound around the iron core B7 on the opposite side of the disk 3 and is arranged at a position facing the objective lens. The direction 9 of the magnetic flux is as shown in the drawing, and there is a push-pull relationship between the coil 6 and the magnetic field generating coil 8.
第２図は本例にかかる光磁気ヘッドの周辺回路をブロ
ック図で示したもので、外部磁界発生用のコイル６には
定電流回路10Aから、磁界発生コイル８には定電流回路1
0Bから、フォーカシングコイル29には駆動回路11からそ
れぞれ電流が供給される。記録／消去指令信号32により
極性切り換え回路A,B（17A,17B）がそれぞれコイル6,8
に流す電流の方向を決定する。また、フォーカス制御回
路に含まれるフォーカス信号検出23、位相補償回路30、
駆動回路11の一部に極性切り換え回路17Cを設け、指令
信号32により制御の極性を切り換える。FIG. 2 is a block diagram showing the peripheral circuit of the magneto-optical head according to the present example. The constant current circuit 10A is used for the external magnetic field generating coil 6 and the constant current circuit 1 is used for the magnetic field generating coil 8.
From 0B, current is supplied to the focusing coil 29 from the drive circuit 11. The polarity switching circuits A and B (17A and 17B) are respectively set to coils 6 and 8 by the recording / erasing command signal 32.
To determine the direction of current flow. Further, the focus signal detection 23 included in the focus control circuit, the phase compensation circuit 30,
A polarity switching circuit 17C is provided in a part of the drive circuit 11, and the control polarity is switched by the command signal 32.
両コイル6,8で発生する磁界はプッシュプルの関係に
あり必ず強めあう方向に作用する。The magnetic fields generated by both coils 6 and 8 are in a push-pull relationship and always act in a mutually reinforcing direction.
発明の効果 以上のように、本発明は、対物レンズの駆動用の駆動
磁界発生部材を従来の永久磁石を用いずに電磁石で構成
し、記録時と消去時で極性を切り替える外部磁界の極性
に合わせ、該駆動用の電磁石の極性を切り替えるように
構成したことにより、外部磁界とコイル駆動用の磁界を
強め合わせて、ディスク面上での磁束密度を増加し、結
果的に外部磁界発生部材に含まれるコイルに流す電流を
低減することができる効果も奏する。As described above, according to the present invention, the driving magnetic field generating member for driving the objective lens is configured by an electromagnet without using the conventional permanent magnet, and the polarity of the external magnetic field is switched between the recording and the erasing. In addition, since the polarity of the driving electromagnet is switched, the external magnetic field and the coil driving magnetic field are strengthened to increase the magnetic flux density on the disk surface, resulting in the external magnetic field generating member. There is also an effect that the current flowing through the included coil can be reduced.
従来対物レンズ駆動用の磁界発生装置からの洩れ磁束
によりディスク面での磁界が記録時と消去時で大きくア
ンバランスしており、その対応としてディスクの抗磁力
を高め、外部磁界発生部材に含まれるコイルに流す電流
を洩れ磁束に対して影響がなくなるほどの磁界が発生す
るよう大きくする必要があった。Conventionally, the magnetic field on the disk surface is largely unbalanced during recording and erasing due to the leakage flux from the magnetic field generator for driving the objective lens, and as a countermeasure, it increases the coercive force of the disk and is included in the external magnetic field generating member. It was necessary to increase the current flowing through the coil so that a magnetic field was generated to such an extent that it had no effect on the leakage magnetic flux.
本発明では対物レンズ駆動部からの洩れ磁束を逆に積
極的に利用しているため洩れ磁束を低減するための手段
はもちろん不要になり、外部磁界発生用コイルへの電流
も大幅に低減できるためコイル自体も小さくなる。In the present invention, since the magnetic flux leaking from the objective lens drive unit is positively utilized, a means for reducing the magnetic flux leak is not required, and the current to the external magnetic field generating coil can be greatly reduced. The coil itself also becomes smaller.
なお、上記説明では洩れ磁束の発生源を対物レンズの
フォーカシング方向駆動用の磁界としたが、もちろんト
ラッキング方向駆動用の磁界としてもなんら問題はな
く、有効な方を、または、両者を用いてもよい。In the above description, the source of the leakage magnetic flux is the magnetic field for driving the objective lens in the focusing direction, but of course there is no problem as the magnetic field for driving the tracking direction, and the effective one or both may be used. Good.
【図面の簡単な説明】 第１図は本発明の一実施例のアクチュエータ−ディスク
−外部磁界発生コイルの関係を示したブロック図、第２
図はその光磁気ヘッドの周辺回路のブロック図、第３図
は従来例の光磁気ヘッドの光学部を示したブロック図、
第４図は従来例の光磁気ヘッドのアクチュエータ−ディ
スク−外部磁界発生コイルの関係を示したブロック図で
ある。 1,7……鉄心A,B、２……ベース、３……ディスク、６…
…外部磁界発生用コイル、８……磁界発生用コイル、15
……対物レンズ、29……フォーカシングコイル。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a relationship between an actuator, a disk, and an external magnetic field generating coil according to an embodiment of the present invention.
FIG. 3 is a block diagram of a peripheral circuit of the magneto-optical head, FIG. 3 is a block diagram showing an optical part of a conventional magneto-optical head,
FIG. 4 is a block diagram showing the relationship between the actuator-disk-external magnetic field generating coil of the conventional magneto-optical head. 1,7 ...... Iron core A, B, 2 ...... Base, 3 ...... Disc, 6 ...
… External magnetic field generating coil, 8… Magnetic field generating coil, 15
…… Objective lens, 29 …… Focusing coil.
Claims (1)
生、消去する光磁気ヘッドであって、レーザ光源から発
せられたレーザビームをディスク上に集光する対物レン
ズと、この対物レンズに固定された部材に巻回され対物
レンズをディスク面に対して垂直方向に駆動するフォー
カシングコイル、および平行方向かつ半径方向に駆動す
るトラッキングコイルと、このコイルに駆動力を与える
ための電磁石で構成された駆動磁界発生部材と前記光磁
気ディスクに対して前記対物レンズの反対側に配置され
た外部磁界発生部材とを有し、前記外部磁界発生部材を
電磁石で構成し、記録／消去で切り替わる外部磁界発生
部材の極性に合わて前記駆動磁界発生部材を構成する電
磁石の極性を外部磁界発生部材より発生する外部磁界と
引き合う方向に切り替えるようにしたことを特徴とする
光磁気ヘッド。1. A magneto-optical head for recording, reproducing and erasing information using a magneto-optical disk, wherein an objective lens for condensing a laser beam emitted from a laser light source on the disk and fixed to the objective lens. It is composed of a focusing coil that is wound around a member that drives the objective lens in a direction perpendicular to the disk surface, a tracking coil that drives in a parallel direction and a radial direction, and an electromagnet that applies a driving force to this coil. An external magnetic field generating member having a driving magnetic field generating member and an external magnetic field generating member arranged on the side opposite to the objective lens with respect to the magneto-optical disk, wherein the external magnetic field generating member is composed of an electromagnet and is switched between recording and erasing. The polarity of the electromagnet constituting the driving magnetic field generating member is cut in a direction in which it attracts the external magnetic field generated by the external magnetic field generating member according to the polarity of the member. Magneto-optical head is characterized in that the obtaining manner.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27355888A JP2676842B2 (en) | 1988-10-28 | 1988-10-28 | Magneto-optical head |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27355888A JP2676842B2 (en) | 1988-10-28 | 1988-10-28 | Magneto-optical head |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02121137A JPH02121137A (en) | 1990-05-09 |
| JP2676842B2 true JP2676842B2 (en) | 1997-11-17 |
Family
ID=17529481
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP27355888A Expired - Fee Related JP2676842B2 (en) | 1988-10-28 | 1988-10-28 | Magneto-optical head |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2676842B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3394210B2 (en) | 1999-03-30 | 2003-04-07 | 富士通株式会社 | Optical disk drive |
| JP4499881B2 (en) * | 2000-07-05 | 2010-07-07 | オリンパス株式会社 | Magneto-optical disk unit |
-
1988
- 1988-10-28 JP JP27355888A patent/JP2676842B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02121137A (en) | 1990-05-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP2676842B2 (en) | Magneto-optical head | |
| JPH0232692B2 (en) | ||
| JP2877889B2 (en) | Magneto-optical recording / reproducing device | |
| KR100285758B1 (en) | Optical pickup actuator using concentration type magnetization method | |
| KR100220965B1 (en) | A tracking apparatus of actuator | |
| KR100291752B1 (en) | An actuating structure in shaft type optical pick-up actuator | |
| JP2904575B2 (en) | Magnetic field modulation magneto-optical recording device | |
| JP3365580B2 (en) | Optical pickup | |
| JPH087537Y2 (en) | Objective lens driving device for magneto-optical recording / reproducing apparatus | |
| JP2840997B2 (en) | Apparatus and method for erasing entire surface of magneto-optical disk medium | |
| JP4294843B2 (en) | Magneto-optical disk unit | |
| JP2560977Y2 (en) | Head device for magneto-optical disk | |
| JPS62285261A (en) | Leakage magnetic field correcting device | |
| JP2790477B2 (en) | Objective lens drive | |
| JPS63281251A (en) | Magneto-optical disk device | |
| JPH0422403Y2 (en) | ||
| JPS63146259A (en) | Magneto-optical recording system | |
| JPS6258441A (en) | Photomagnetic recording and reproducing device | |
| JPH035902A (en) | Magnetic head actuator mechanism for magneto-optical recording device | |
| JPH05290423A (en) | Magneto-optical recording disk device | |
| JPH0215443A (en) | Magneto-optical disk device | |
| JPH04222903A (en) | Magneto-optical driving device | |
| JPS61153857A (en) | Photomagnetic recording and reproducing device | |
| JPH03130949A (en) | Optics driving device for optical information recording and reproducing device | |
| JPS62226455A (en) | Photomagnetic recording and reproducing head |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |