JPH02173903A - Electromagnet for magneto-optical disk - Google Patents
Electromagnet for magneto-optical diskInfo
- Publication number
- JPH02173903A JPH02173903A JP32834788A JP32834788A JPH02173903A JP H02173903 A JPH02173903 A JP H02173903A JP 32834788 A JP32834788 A JP 32834788A JP 32834788 A JP32834788 A JP 32834788A JP H02173903 A JPH02173903 A JP H02173903A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic field
- electromagnet
- recording
- erasing
- magneto
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 230000005415 magnetization Effects 0.000 claims description 3
- 230000020169 heat generation Effects 0.000 abstract description 6
- 230000003313 weakening effect Effects 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 6
- 230000007246 mechanism Effects 0.000 description 4
- 230000003287 optical effect Effects 0.000 description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000005374 Kerr effect Effects 0.000 description 1
- 229910000828 alnico Inorganic materials 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
Landscapes
- Recording Or Reproducing By Magnetic Means (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は、光磁気記録、（特に熱・磁気記録）に使用さ
れる電磁石に関し、特に一定バイアス磁Ｗの発生装置を
備えた電磁石に関する。DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an electromagnet used for magneto-optical recording (especially thermal/magnetic recording), and more particularly to an electromagnet equipped with a constant bias magnet W generator.
（従来の技術）
書換え可能な光磁気ディスクを使用する光磁気記録装置
を例に挙げると、消去時と記録時において媒体に対し垂
直にあるＩ／ベル以上の磁界を印加し、レーザー光線を
照射することで部分的に温度を上げ、その部分における
媒体の磁化の向きを外部の磁界の方向に合わぜる熱磁気
記録を行い、方向が消去状態、その反対方向が記録状態
に対応する仕組みで情報の記録、消去を行う。このよう
に記録装置は媒体に対し、消去時と記録時で逆の磁界を
加える必要があるが従来この用途には、消去時と記録時
によって電流の向きを変えて磁界の向きを変える、鉄心
から成るＥ型ヨークの中心部分にコイルを巻いた型の電
磁石、あるいは回転機構によって磁界の向きを変える永
久磁石が使われてきた。そして、消去時と記録時とのい
ずれにおいても同一の強度の磁界が一般に用いられてき
た。(Prior art) For example, in a magneto-optical recording device that uses a rewritable magneto-optical disk, a magnetic field greater than I/bel perpendicular to the medium is applied during erasing and recording, and a laser beam is irradiated. This causes thermomagnetic recording in which the temperature is raised locally and the direction of magnetization of the medium in that area is aligned with the direction of the external magnetic field. Information is stored in a mechanism in which the direction corresponds to the erased state and the opposite direction corresponds to the recorded state. Records and erases information. In this way, recording devices need to apply opposite magnetic fields to the medium during erasing and recording, but conventionally, for this purpose, iron cores have been used to change the direction of the magnetic field by changing the direction of the current depending on when erasing and recording. Electromagnets with a coil wound around the center of an E-shaped yoke, or permanent magnets that change the direction of the magnetic field using a rotating mechanism, have been used. A magnetic field of the same strength has generally been used both during erasing and during recording.
（発明が解決しようとする課Ｍ）
上記用途において媒体が必要とする磁界を得るなめには
、電磁石を使用した場合、必要なコイルの巻数が必要な
磁界強度を得るために設計上はぼ決まってしまいそれ以
上の小型化が難しく、また必要なコイルの巻数に起因し
て電流による発熱も問題になることが多い、一方、永久
磁石を使用する場合、これらは問題にならないが、反対
に回転機構を必要とし、磁界の反転に時間がかがるとい
った難点が存在する。(Problem M to be solved by the invention) In order to obtain the magnetic field required by the medium in the above applications, when an electromagnet is used, the required number of turns of the coil is not determined in design in order to obtain the required magnetic field strength. This makes further miniaturization difficult, and heat generation due to current is often a problem due to the number of turns of the coil required.On the other hand, when using permanent magnets, these do not pose a problem, but on the other hand, they rotate in the opposite direction. There are disadvantages in that it requires a mechanism and takes time to reverse the magnetic field.
したがって、本発明の目的は、特に消去時に必要な磁界
を得るために、予め一定の磁界を一方向く消去時に加算
される方向）に加えておき、その代わり、必要なコイル
の巻数を減少して、電磁石の小型化を企てると共に、電
流による発熱の問題を最少にした光磁気ディスク用電磁
石を提供することにある。Therefore, an object of the present invention is to apply a certain magnetic field in advance in one direction (in the direction added during erasing) in order to obtain the magnetic field necessary especially during erasing, and instead reduce the number of turns of the required coil. Another object of the present invention is to provide an electromagnet for a magneto-optical disk that minimizes the problem of heat generation due to current while attempting to downsize the electromagnet.
（課題を解決するための手段）
上述の目的を達成するために、本発明は光磁気記録のよ
うに磁化の向きを制御することにより記録、再生する媒
体を用いた情報記録再生装置で用いる光磁気ディスク用
電磁石において、消去及び記録時に加える磁界を発生す
るための電磁石に対して予め一定の磁界を一方向に加え
ておくことを特徴とする電磁石を採用するものである。(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides an optical system for use in an information recording and reproducing apparatus using a medium that records and reproduces information by controlling the direction of magnetization, such as magneto-optical recording. The electromagnet for magnetic disks employs an electromagnet characterized in that a fixed magnetic field is applied in one direction in advance to the electromagnet for generating the magnetic field applied during erasing and recording.
（作用）
一般的にまず消去を行った後に記録をする形式において
消去時および記録時にそれぞれに必要な磁界が必要とさ
れるが、必ずしも消去時と記録時で同じ磁界強度が必要
ではなく、消去時は比較的強い磁界が望まれ記録時は弱
くても十分機能する。(Function) In general, in a format where data is first erased and then recorded, magnetic fields are required for erasing and recording, but the same magnetic field strength is not necessarily required for erasing and recording. At times, a relatively strong magnetic field is desired, but at the time of recording, even a weak magnetic field can function satisfactorily.
本発明は、この特性を利用し、永久磁石である程度の消
去方向に対する磁界を常時加えておき、すなわちバイア
ス磁界を予め与えておき、その上で電磁石を駆動する。The present invention takes advantage of this characteristic by constantly applying a certain degree of magnetic field in the erasing direction using a permanent magnet, that is, applying a bias magnetic field in advance, and then driving the electromagnet.
この場合、消去時においては永久磁石によって予め与え
られたバイアス磁界が電磁石によって発生された磁界に
加えられて必要な磁界を得ることができ、一方記録時に
は電磁石によって発生される磁界が永久磁石によって予
め与えられた磁石により減じられるが、記録時には前述
のように弱くて十分機能するので、使用上さしつかえな
いものである。このようにすることで電磁石の負担を少
なくでき、より一層の小型化が可能になり、電流を減ら
せることで発熱も抑えられる。また、回転機構もいらず
磁界の反転も高速に行える。In this case, during erasing, the bias magnetic field pre-given by the permanent magnet is added to the magnetic field generated by the electromagnet to obtain the required magnetic field, while during recording, the magnetic field generated by the electromagnet is pre-applied by the permanent magnet. Although it is reduced by the provided magnet, it is weak and functions well during recording as described above, so it is not a problem in use. By doing this, the burden on the electromagnet can be reduced, further miniaturization is possible, and heat generation can also be suppressed by reducing the current. Furthermore, there is no need for a rotating mechanism, and the magnetic field can be reversed at high speed.
（実施例） 次に、本発明を図面を参照して説明する。(Example) Next, the present invention will be explained with reference to the drawings.
第１図は、本発明の光磁気ディスク用電磁石の斜視図で
ある。第２図は、本発明の光磁気ディスク用電磁石の正
面図である。第３図は、本発明の光磁気ディスク用電磁
石の特性を示すグラフである。第４図は、本発明の光磁
気ディスク用電磁石を用いた光磁気記録装置の内部を示
す正面図である。第５図は、第４図の側面図である。FIG. 1 is a perspective view of an electromagnet for a magneto-optical disk according to the present invention. FIG. 2 is a front view of the magneto-optical disk electromagnet of the present invention. FIG. 3 is a graph showing the characteristics of the magneto-optical disk electromagnet of the present invention. FIG. 4 is a front view showing the inside of a magneto-optical recording device using the magneto-optical disk electromagnet of the present invention. FIG. 5 is a side view of FIG. 4.
第１図および第２図を最初に参照すると、本発明の光磁
気ディスク用電磁石（以下単に電磁石という）１０が示
されている。電磁石１ｏは鉄心がら成るＥ型ヨーク１２
と、このヨーク１２の中心部分に巻かれたコイル１４と
、ヨーク１２の両端部分の端部にそれぞれ固定した永久
磁石１６と、から成る。永久磁石１６は、例えばＮ極が
内方にかつＳ極が外方に向くように固定されており、こ
の向きは、消去時にコイルに流される電流によって発生
される磁界に加算され、かつ記録時にコイルに流される
電流によって発生される磁界を減じる向きである。なお
、取付ける磁石の残留磁束密度は、消去方法の磁界をど
のくらい増すかによるが、１０００〜３０００ガウス程
度が適しており、この値は一般的なアルニコ磁石やフェ
ライト磁石で十分実現可能である。Referring first to FIGS. 1 and 2, there is shown a magneto-optical disk electromagnet (hereinafter simply referred to as an electromagnet) 10 of the present invention. The electromagnet 1o is an E-type yoke 12 consisting of an iron core.
It consists of a coil 14 wound around the center of the yoke 12, and permanent magnets 16 fixed to the ends of both ends of the yoke 12, respectively. The permanent magnet 16 is fixed such that, for example, the N pole faces inward and the S pole faces outward, and this orientation is such that it is added to the magnetic field generated by the current flowing through the coil during erasing, and is added to the magnetic field during recording. It is oriented to reduce the magnetic field generated by the current flowing through the coil. Note that the residual magnetic flux density of the attached magnet depends on how much the magnetic field is increased in the erasing method, but a suitable value is about 1000 to 3000 Gauss, and this value can be sufficiently achieved with a general alnico magnet or ferrite magnet.
第３図は、第１図および第２図に示す電磁石１０によっ
て得られたヨークの端部がら垂直方向に離れた距離に対
する磁束密度の特性を示すグラフである。このグラフは
第２図に示す電磁石の特性（磁心比透磁率、起磁力、永
久磁石の磁界強度、外形寸法）に基づいて得られたもの
である。図中、Ｏ印は永久磁石＋電磁石（消去時）を示
し、Ｘ印は電磁石のみを示し、Δ印は永久磁石ト電磁石
（記録時）を示Ｌ、・印は永久磁石のみを示す。FIG. 3 is a graph showing the characteristics of magnetic flux density with respect to the vertical distance from the end of the yoke obtained by the electromagnet 10 shown in FIGS. 1 and 2. FIG. This graph was obtained based on the characteristics of the electromagnet shown in FIG. 2 (core relative permeability, magnetomotive force, magnetic field strength of the permanent magnet, external dimensions). In the figure, the symbol O indicates a permanent magnet + electromagnet (during erasing), the symbol X indicates only an electromagnet, the symbol Δ indicates a permanent magnet plus an electromagnet (during recording), L, and the symbol • indicate only a permanent magnet.
第３図から明らかなように、本発明の電磁石］０を用い
ることにより、消去時には永久磁石による磁界と電磁石
による磁界とが算術加算され、強い強度の磁界が得られ
る一方、記録時には、電磁石による磁界から永久磁石に
よる磁界を減じた磁界が得られるが、前述のように記録
時には消去時より低い強度で十分であるので、使用上問
題は生じない。As is clear from FIG. 3, by using the electromagnet]0 of the present invention, the magnetic field by the permanent magnet and the magnetic field by the electromagnet are arithmetically added during erasing, and a strong magnetic field is obtained, while during recording, the magnetic field due to the electromagnet is A magnetic field obtained by subtracting the magnetic field generated by the permanent magnet from the magnetic field is obtained, but as mentioned above, a lower intensity is sufficient during recording than during erasing, so no problems arise in use.
また、このグラフから、消去時および記録時に必要な強
度の磁界が得られる範囲内で、電磁石と電磁石により作
用させられる記録ディスクとの距離を任意の適当な値に
選ぶことができる。Also, from this graph, the distance between the electromagnet and the recording disk acted upon by the electromagnet can be selected to any appropriate value within the range in which a magnetic field of the strength required during erasing and recording can be obtained.
次に、第４図おＪ：び第５図を参照して、本発明の電磁
石を光磁気ディスク記録装置に特に、いわゆる熱磁気記
録装置に適用した実施例に関連し、て説明する。しかし
ながら、本発明は熱磁気記録装置に限定されるものでは
なく、一般にレーザー光を用いる広義の光磁気ディスク
記録装置に適用できるものである。熱磁気記録方法は、
−・般に、消去時にディスク等の記録媒体に一方向の磁
界をか（・）、一方記録時に記録媒体に逆方向の磁界を
かけながらレーザー光のスポットを与えて、記録すべき
情報に応じて記録媒体を部分的に加熱して、照射したス
ポット領域だけを外部磁界と同方向に磁化して、記録を
行うものである。このことを行うために、光磁気ディス
ク記録装置２０はフレーム２２の上部内部に本発明の電
磁石】０を固定している。フレーム２２の基部にはディ
スクドライブ２４が配置されており、このディスクドラ
イブ２４はスピンドルモータ（図示せず）およびドライ
ブモータの垂直上方に突出するスピンドル固定したター
ンテーブル２４ａを有し、ターンデープル２４ａには記
録するためのディスク２６が載せられる。記録装置２０
は、さらに、フレーム２２の基部に矢印“′Ｘ′°で示
すように半径方向に移動可能に取（＝ｔ ｉ′Ｉた光ピ
ツクアップ２８を有している。Next, with reference to FIGS. 4 and 5, an explanation will be given of an embodiment in which the electromagnet of the present invention is applied to a magneto-optical disk recording device, particularly a so-called thermomagnetic recording device. However, the present invention is not limited to thermomagnetic recording devices, but can generally be applied to magneto-optical disk recording devices in a wide sense that use laser light. The thermomagnetic recording method is
- Generally, when erasing, a magnetic field is applied to a recording medium such as a disk in one direction (・), while when recording, a spot of laser light is applied while applying a magnetic field in the opposite direction to the recording medium, depending on the information to be recorded. Recording is performed by partially heating the recording medium and magnetizing only the irradiated spot area in the same direction as the external magnetic field. To accomplish this, the magneto-optical disk recording device 20 has an electromagnet according to the present invention fixed inside the upper part of the frame 22. A disk drive 24 is disposed at the base of the frame 22, and the disk drive 24 has a spindle motor (not shown) and a turntable 24a fixed to a spindle that projects vertically above the drive motor. A disc 26 for recording is loaded. Recording device 20
Further, the optical pickup 28 is mounted at the base of the frame 22 so as to be movable in the radial direction as indicated by the arrow "'X'°".
この光ピツクアップ２８は記録媒体のディスクの記録領
域の範囲内にわたって可動であり、−Ｊ一般には記録時
光レーザーを記録媒体に向けて照射ｊ−で、前述のよう
に記録を行い、また読取り時には光ｌ／−ザーを記録媒
体に向けて照射して、その反射光を検出して、検出した
反射光の特性（ファラデー効果、またはカー効果）によ
り読取りを行う。This optical pickup 28 is movable within the range of the recording area of the disk of the recording medium, and generally performs recording as described above by irradiating an optical laser toward the recording medium during recording, and also emits light during reading. The recording medium is irradiated with a l/- laser, the reflected light is detected, and reading is performed based on the characteristics (Faraday effect or Kerr effect) of the detected reflected light.
なお、前述の電磁石１ｏは、第５図から明らかなように
、記録媒体のディスクの記録範囲内にわたって半径方向
に充分カバーする［１］を有し、これにより、消去時お
よび記録時にディスクの回転に伴って順次全領域にわた
ってそれぞれ一定の強度の磁界をかけることができるよ
うに構成されている。As is clear from FIG. 5, the electromagnet 1o described above has a radius [1] that sufficiently covers the recording range of the disk of the recording medium in the radial direction, thereby preventing rotation of the disk during erasing and recording. The structure is such that a magnetic field of a constant strength can be applied sequentially over the entire area as the area increases.
以上、本発明の電磁石の好まｉ〜い実施例について説明
してきたが、本発明はこの実施例に限定されるしのでは
なく、他の変形を可能であり、そのような変形も本発明
は含むものである０例えば、本発明の電磁石としてＥ型
ヨークにコイルを巻いた電磁石を説明してきたが、本発
明は一般のコ形状型ヨークの２つの脚の一方または両方
の脚部または２つの脚部を連結している中間部分にコイ
ルを巻いた電磁石にも適用できるものである。さらにま
た、Ｅ型ヨークの両端部に永久磁石を固定するのに加え
て、中間部分に他の永久磁石夕固定することもできるも
のである。Although preferred embodiments of the electromagnet of the present invention have been described above, the present invention is not limited to these embodiments, and other modifications are possible, and such modifications are not limited to the present invention. For example, although the electromagnet of the present invention has been described as an electromagnet in which a coil is wound around an E-shaped yoke, the present invention can be applied to one or both of the two legs of a general U-shaped yoke, or two legs. It can also be applied to electromagnets that have a coil wound around the middle part connecting them. Furthermore, in addition to fixing permanent magnets to both ends of the E-type yoke, other permanent magnets can also be fixed to the middle part.
（発明の効果）
以上詳細に説明したように、本発明は、電磁石に一定磁
界を一方向に加えるように永久磁石を固定することによ
り、消去時の磁界の強度を弱めることなく、コイルの巻
数を減じ、それによ−）て電磁石を小型化し、かつ電流
による発熱を最少に抑制することができるものである。(Effects of the Invention) As explained in detail above, the present invention has the advantage of fixing a permanent magnet so as to apply a constant magnetic field to the electromagnet in one direction, thereby reducing the number of turns of the coil without weakening the strength of the magnetic field during erasing. This makes it possible to downsize the electromagnet and minimize heat generation due to current.
第１図は、本発明の光磁気ディスク用電磁石の斜視図で
ある。
第２図は、本発明の光磁気ディスク用電磁石の正面図で
ある。
第３図は、本発明の光磁気ディスク用電磁石の特性を示
すグラフである。
第４図は、本発明の光磁気ディスク用電磁石を用いた光
磁気記録装置の内部を示す正面図である。
第５図は、
第４図の側面図である。
０・・・光磁気ディスク用電磁石、
・ヨーク、
４・・・コイル、
６・・・永久磁石。
第
図
距
乾
（ｍ）
第
菖
図
第
図
○
第
図
第
図FIG. 1 is a perspective view of an electromagnet for a magneto-optical disk according to the present invention. FIG. 2 is a front view of the magneto-optical disk electromagnet of the present invention. FIG. 3 is a graph showing the characteristics of the magneto-optical disk electromagnet of the present invention. FIG. 4 is a front view showing the inside of a magneto-optical recording device using the magneto-optical disk electromagnet of the present invention. FIG. 5 is a side view of FIG. 4. 0... Electromagnet for magneto-optical disk, - Yoke, 4... Coil, 6... Permanent magnet. Diagram distance dry (m) Diagram Diagram Diagram ○ Diagram Diagram
Claims (2)
より記録、再生する媒体を用いた情報記録再生装置で用
いる光磁気ディスク用電磁石において、消去及び記録時
に加える磁界を発生するための電磁石に対して予め一定
の磁界を一方向に加えておくことを特徴とする電磁石。(1) An electromagnet for generating a magnetic field applied during erasing and recording in an electromagnet for magneto-optical disks used in information recording and reproducing devices that use media that record and reproduce by controlling the direction of magnetization, such as magneto-optical recording. An electromagnet characterized by applying a fixed magnetic field in one direction in advance to the magnet.
消去時の磁界を強める方向に設定しておくことを特徴と
する電磁石。(2) The electromagnet according to claim 1, wherein the constant magnetic field is set in a direction that strengthens the magnetic field during erasing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32834788A JPH02173903A (en) | 1988-12-26 | 1988-12-26 | Electromagnet for magneto-optical disk |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32834788A JPH02173903A (en) | 1988-12-26 | 1988-12-26 | Electromagnet for magneto-optical disk |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02173903A true JPH02173903A (en) | 1990-07-05 |
Family
ID=18209225
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP32834788A Pending JPH02173903A (en) | 1988-12-26 | 1988-12-26 | Electromagnet for magneto-optical disk |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02173903A (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61104443A (en) * | 1984-10-26 | 1986-05-22 | Nec Corp | Photomagnetic recording/production/erasion device |
| JPS61208603A (en) * | 1985-03-12 | 1986-09-17 | Fujitsu Ltd | Bias magnetic field generating device |
| JPS61287003A (en) * | 1985-06-13 | 1986-12-17 | Toshiba Corp | Optical information recording and reproducing device |
-
1988
- 1988-12-26 JP JP32834788A patent/JPH02173903A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61104443A (en) * | 1984-10-26 | 1986-05-22 | Nec Corp | Photomagnetic recording/production/erasion device |
| JPS61208603A (en) * | 1985-03-12 | 1986-09-17 | Fujitsu Ltd | Bias magnetic field generating device |
| JPS61287003A (en) * | 1985-06-13 | 1986-12-17 | Toshiba Corp | Optical information recording and reproducing device |
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