JPS59152503A - Optical pickup device - Google Patents
Optical pickup deviceInfo
- Publication number
- JPS59152503A JPS59152503A JP58025495A JP2549583A JPS59152503A JP S59152503 A JPS59152503 A JP S59152503A JP 58025495 A JP58025495 A JP 58025495A JP 2549583 A JP2549583 A JP 2549583A JP S59152503 A JPS59152503 A JP S59152503A
- Authority
- JP
- Japan
- Prior art keywords
- magnetic
- recording medium
- magnetic field
- magnetic circuit
- medium
- 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.)
- Granted
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
- G11B11/1055—Disposition or mounting of transducers relative to record carriers
- G11B11/10552—Arrangements of transducers relative to each other, e.g. coupled heads, optical and magnetic head on the same base
- G11B11/10554—Arrangements of transducers relative to each other, e.g. coupled heads, optical and magnetic head on the same base the transducers being disposed on the same side of the carrier
Landscapes
- Recording Or Reproducing By Magnetic Means (AREA)
- Optical Head (AREA)
Abstract
Description
【発明の詳細な説明】
技術分野
本発明は、電磁力を利用してレンズ焦点の調整等を行う
光ピツクアップ装置角に関し、特に磁性体薄膜からなる
記録媒体」二に光ビームを集光照射して情報の記録再生
および消去を行う光磁気記録装置の光ピツクアップ装置
に好適なものである。[Detailed Description of the Invention] Technical Field The present invention relates to an optical pickup device angle that uses electromagnetic force to adjust a lens focus, etc., and in particular to an optical pickup device that focuses a light beam on a recording medium made of a magnetic thin film. The present invention is suitable for an optical pickup device of a magneto-optical recording device that records, reproduces and erases information using a magneto-optical recording device.
従来技術
従来この種の光磁気記録装置では、一般に情報を記録す
る際には、GdTbFe等の一軸異方性磁性体薄IIり
からなる円板状の記録媒体に光ビームをスポット状に集
光して照射し、その照射部分をキューり点付近の温度に
加熱することにより、磁化反転領域を形成し、それによ
り情報信号の記録を行っている。さらにその際、一様に
垂直方向に磁化された記録媒体上に対して電磁石等によ
り磁化反転を容易にする方向に磁界を付与しながら光ビ
ームの照射をしている。−力1.5+2録された情報ご
再生する際には、上述の記録媒体上に情報読取に適した
比較的弱い光ビームを集光して照射し、その光ビームの
反射光または透過光のカー回転角またはファラデー回転
角が磁化方向に応して異なることを利用して再生信号を
得ている。Prior Art Conventionally, in this type of magneto-optical recording device, when recording information, a light beam is generally focused into a spot on a disk-shaped recording medium made of a thin uniaxially anisotropic magnetic material such as GdTbFe. By heating the irradiated portion to a temperature near the cue point, a magnetization reversal region is formed, thereby recording an information signal. Further, at this time, the light beam is irradiated onto the recording medium that is uniformly magnetized in the perpendicular direction while applying a magnetic field using an electromagnet or the like in a direction that facilitates magnetization reversal. - When reproducing recorded information, a relatively weak light beam suitable for reading information is focused onto the recording medium mentioned above, and the reflected light or transmitted light of the light beam is The reproduced signal is obtained by utilizing the fact that the Kerr rotation angle or Faraday rotation angle differs depending on the magnetization direction.
このため、従来装置δでは、情tfuの記録再生時に光
ビームを記録媒体上に常に集光させるために、光学系全
体または対物レンズ等の光学系の−・部を電磁力を利用
してフォーカス力向(光軸方向)に駆動する駆動機構を
備えた光ピ・ンクアップ装置と、情報の記録時に、記録
媒体に所定方向の磁界を刊年する電磁石等の磁界刊年装
置゛1ηをイ〕する。For this reason, in the conventional device δ, in order to constantly focus the light beam on the recording medium when recording and reproducing information TFU, the entire optical system or a portion of the optical system such as the objective lens is focused using electromagnetic force. An optical pickup device equipped with a drive mechanism that drives in the force direction (optical axis direction) and a magnetic field device such as an electromagnet that applies a magnetic field in a predetermined direction to a recording medium when recording information [1η] do.
第1図および第2同は、それぞれこのような従来の光ピ
ツクアップ装置と磁界付ター装置の構成例を〉J\す。Figures 1 and 2 show examples of the configuration of such a conventional optical pickup device and magnetic field attachment device, respectively.
まず、第1図の従来例を説明すると、図の光ピツクアッ
プ装置1は、集光用の対物レンズ2、対物レンズ2を支
持する鏡+J3 、fm抽3を垂的力向に移動可能に支
持する上下−・対の弾ヒ1;支杓休4aおよび4b、弾
性支持体4aおよび4bの外縁を両肩する筐体5、鏡筒
3に同定された鏡筒駆動用の駆動コイル6、駆動コイル
6に磁界を与える一対のヨーク7aおよび7b、そのヨ
ークと永久磁石8とならなる磁気回路、光ビームを水平
力向に変位させるカルハノミラ−9とから構成され、光
ビーム10が照射される記録媒体11の記録面と平行に
対向して配設される。−力、情報の記録時に記録媒体1
1の而の磁界を付与する磁界付与装置に当る電磁石12
は、記録媒体1[の両面を挟むコの字型の強磁性体部材
13とコイル14とを治し、光ピ・ンクア・ンプ装置1
の筐体5に固定して一体動する。First, to explain the conventional example shown in Fig. 1, the optical pickup device 1 shown in the figure supports an objective lens 2 for condensing light, a mirror +J3 supporting the objective lens 2, and an fm drawer 3 movable in the vertical force direction. A pair of upper and lower bullets 1; support rests 4a and 4b; a housing 5 that covers the outer edges of the elastic supports 4a and 4b; a drive coil 6 for driving the lens barrel identified in the lens barrel 3; The recording device is composed of a pair of yokes 7a and 7b that apply a magnetic field to the coil 6, a magnetic circuit that serves as a permanent magnet 8 between the yokes, and a Calhano mirror 9 that displaces the light beam in the horizontal force direction, and is irradiated with a light beam 10. It is disposed parallel to and facing the recording surface of the medium 11. - Recording medium 1 when recording power and information
An electromagnet 12 corresponding to a magnetic field applying device that applies a magnetic field of 1.
The U-shaped ferromagnetic member 13 and the coil 14 sandwiching both sides of the recording medium 1 are fixed, and the optical pin-qua-amp device 1 is assembled.
It is fixed to the casing 5 of and moves integrally.
この光ピツクアップ装置1は記録媒体11と平行に相対
的に移動しながら、光ビーム10により記録媒体11
、f:に情報をトランク状に記録し、情報再生H)lに
は記録媒体1上に既に形成された情報l・う・ンク(不
図示)を追跡しながら、反射光により情報の再生を行う
。その時、記録媒体11と光ピ・ンクアンプ装置1との
相対的距離は記録媒体11の表面の凹凸や移動時の上下
動および外部からの振動等により変化する。そのため、
光ヒームlOが常に記録媒体11上に焦点を鯖2りζよ
うに、不図示の光検出器で焦点ずれの誤差(i号を検出
し、その検出値に応じて対物レンズ2を鏡筒3および弾
性支持体4aおよび4bを介して駆動コイル6と磁気回
路?a、7bおよび8とで構成された駆動装置によりフ
ォーカスカriiJにeイ立させるいわゆるフォーカス
制御を行っている。さらに同時に、光ビー1.1oが一
度把らえた情報トラックから外れないように、不図示の
別に設けた光検出器でトラックずれ量を検出し、その検
出値に応じたカルバノミラ−8を回Φハ駆動することに
より、光ビーム10を記#!、媒体11の面とで変位さ
せるいわゆるトラッキング制御を行っている。This optical pickup device 1 picks up the recording medium 11 with a light beam 10 while moving relatively parallel to the recording medium 11.
, f: in the form of a trunk, and the information reproduction H)l reproduces the information using reflected light while tracking the information (not shown) already formed on the recording medium 1. conduct. At this time, the relative distance between the recording medium 11 and the optical pink amplifier device 1 changes depending on the unevenness of the surface of the recording medium 11, vertical movement during movement, external vibrations, and the like. Therefore,
In order to ensure that the optical beam 10 is always focused on the recording medium 11, a photodetector (not shown) detects the focal shift error (i) and adjusts the objective lens 2 to the lens barrel 3 according to the detected value. A so-called focus control is performed to set the focus force by a drive device composed of a drive coil 6 and magnetic circuits ?a, 7b and 8 via the elastic supports 4a and 4b. In order to prevent the beam 1.1o from deviating from the information track once grasped, the amount of track deviation is detected by a separately provided photodetector (not shown), and the carbanomirror 8 is driven in accordance with the detected value. Thus, so-called tracking control is performed in which the light beam 10 is displaced with respect to the surface of the medium 11.
第2図の従来例では、光ピックアップ装置買1は上述の
第1図のものと同様のものであるか、磁界を付与する磁
界付与−装置12aが、記録媒体11の光ピンクアップ
装誇側の面に対峙して配置した環状コイル1.4aと、
記録媒体11を挟んで光ピツクアップ装置と反対側の面
に対向して配置した棒状の強磁性体磁極13aとから構
成されている点が與なる。情報の記録時には、コイル1
4aに電流を流して磁界を発生させ、記録媒体11を挟
んで反射側にある磁極13aを磁化することにより、記
録媒体11にかかる磁界を強めている。In the conventional example shown in FIG. 2, the optical pickup device 1 is the same as that shown in FIG. an annular coil 1.4a disposed facing the surface of the
Another advantage is that it is composed of a rod-shaped ferromagnetic pole 13a disposed opposite to the optical pickup device with the recording medium 11 in between. When recording information, coil 1
The magnetic field applied to the recording medium 11 is strengthened by passing a current through the recording medium 4a to generate a magnetic field and magnetizing the magnetic pole 13a on the reflective side with the recording medium 11 in between.
しかしながら、第1図または第2図に示すような従来の
磁界刊年装置12または12aにより必要な磁界を得る
ためには、そのコ・rル14または14aのターン数(
巻数)を多くしたり、コイル14または14aに流す印
ノJ10E流を大きくする必要かあった。However, in order to obtain the necessary magnetic field with the conventional magnetic field generating device 12 or 12a as shown in FIG. 1 or 2, the number of turns of the coil 14 or 14a (
It was necessary to increase the number of turns) or increase the J10E current flowing through the coil 14 or 14a.
そのため、コイル14または14aの体積が増大し、ス
ペース的に配置が困難になったり、光ピ・ンクアップ装
置1にかかる重刑が増加するという問題かあった。さら
に、上述の印加電流による発熱等も記8媒体等に悪影響
を与えるという問題も生じた。This increases the volume of the coil 14 or 14a, making it difficult to arrange it in terms of space, and increasing the burden on the optical pickup device 1. Furthermore, there has been a problem in that the heat generated by the above-mentioned applied current has an adverse effect on the medium and the like.
目的
そこで、本発明は」二連した点に鑑みて、光ピンクアン
プ装y1の対物レンズを駆動させる磁気回路の一部から
伸ばした強磁性体を記録媒体の記録面に対向して突設す
ることにより、磁気回路の漏洩磁束を有効に利用して記
録媒体に対する磁界(=f与かできるようにし、それに
より光ピ・ンクア・ンプ装置を含む光ヘツド全体の正量
や容積を軽減し、かつ5?:、熱等の悪影響のないよう
にした光ビ・ンクアップ装置を提供することを目的とす
る。Purpose: Therefore, in view of the two points, the present invention provides a ferromagnetic material extended from a part of the magnetic circuit for driving the objective lens of the optical pink amplifier device y1, and protrudes from a part of the magnetic circuit to face the recording surface of the recording medium. By doing so, it is possible to effectively utilize the leakage magnetic flux of the magnetic circuit to apply a magnetic field (=f) to the recording medium, thereby reducing the amount and volume of the entire optical head including the optical pump device. And 5?: An object of the present invention is to provide an optical link-up device which is free from adverse effects such as heat.
実施例 以下、図面を参照して本発明の詳細な説明する。Example Hereinafter, the present invention will be described in detail with reference to the drawings.
第3図は本発明光ピツクアンプ装置の構成の一例を示し
、ここで第1図の従来装置と同様な部所には同一符号を
伺してその詳細な説明を省略する。第3図の光ピツクア
ップ装置31が第1図の従来装置lと特に異なる点は、
一対のヨーク7aおよび7bと永久磁石8とから構成さ
れた磁気回路の一部、例えば一方のヨーク?bの先端に
強磁性体の突起部32を固設し、この突起部32を記録
媒体11の記録面に対峙して配置していることである。FIG. 3 shows an example of the configuration of an optical pickup device according to the present invention, in which parts similar to those of the conventional device shown in FIG. 1 are denoted by the same reference numerals, and detailed explanation thereof will be omitted. The optical pickup device 31 shown in FIG. 3 is particularly different from the conventional device 1 shown in FIG.
A part of a magnetic circuit composed of a pair of yokes 7a and 7b and a permanent magnet 8, for example, one yoke? A protrusion 32 made of ferromagnetic material is fixed at the tip of b, and this protrusion 32 is disposed facing the recording surface of the recording medium 11.
これにより、」−述の磁気回路から漏れる漏洩磁束は上
述の突起部32を介して図の矢印33で示すように、記
録媒体llの近くまで導かれ、記録媒体上で磁界が強め
られる。従って、情報の記録再生面には、突起部32を
介して与えられる磁気回路の漏洩磁束により、記録媒体
上に磁化反転を起こし易い方向の磁界が作用しているか
ら、従来とII’?I EQ )こ光ビームの照射によ
る情報記録を行うことができる。なお、同一の光ピツク
アップ装置で情報を再生する場合にも、読取用の光ビー
ムは書込用の光ビームより弱いので、上述の磁界の作用
にかかわらず磁化回転を起こさずに情報が再生できる。As a result, the leakage magnetic flux leaking from the magnetic circuit mentioned above is guided to the vicinity of the recording medium 11 through the above-mentioned protrusion 32, as shown by the arrow 33 in the figure, and the magnetic field is strengthened on the recording medium. Therefore, on the information recording/reproducing surface, a magnetic field in a direction that tends to cause magnetization reversal on the recording medium acts on the information recording/reproducing surface due to the leakage magnetic flux of the magnetic circuit applied via the protrusion 32. IEQ) Information can be recorded by irradiation with a light beam. Note that even when reproducing information using the same optical pickup device, the reading light beam is weaker than the writing light beam, so information can be reproduced without magnetization rotation regardless of the effect of the magnetic field described above. .
このように、本実施例によれば、対物レンズ2を駆動す
る磁気回路の漏洩磁束を利用して記録媒体に対する磁界
付与が行えるので、従来のような電磁石やコイル等から
なる磁気付与装置が不要になり、その結果、光ピツクア
ップ装置を含む光ヘツド全体の重量や容積を大幅に軽減
し、かつ印加電流による発熱等の悪影響を除去すること
ができるという効果が得られる。In this way, according to this embodiment, the magnetic field can be applied to the recording medium using the leakage magnetic flux of the magnetic circuit that drives the objective lens 2, so a conventional magnetic application device consisting of an electromagnet or a coil is not required. As a result, it is possible to significantly reduce the weight and volume of the entire optical head including the optical pickup device, and to eliminate adverse effects such as heat generation due to applied current.
第4図は本発明の他の実施例を示し、図の光ピツクアッ
プ装置41は第3図の前実施例の装置31とほぼ同様な
構成であるが、記録媒体11を挟んで突起部32にほぼ
対向する位置に棒状の強磁性体からなる磁束集中用の部
材42を配設している点が異なる。そこで、第4図の本
実施例では、磁気回路の突起部32から出た漏洩磁束が
記録媒体11を通して強磁性体部材42に集中するので
、記録媒体11に付与する磁界の強さをさらに大きくす
ることができる。なお、上述の部材42を磁界強度に応
じて移動可能にしてもよい。FIG. 4 shows another embodiment of the present invention. The optical pickup device 41 shown in the figure has almost the same structure as the device 31 of the previous embodiment shown in FIG. The difference is that a magnetic flux concentration member 42 made of a rod-shaped ferromagnetic material is disposed at substantially opposing positions. Therefore, in the present embodiment shown in FIG. 4, the leakage magnetic flux coming out of the protrusion 32 of the magnetic circuit passes through the recording medium 11 and concentrates on the ferromagnetic member 42, so the strength of the magnetic field applied to the recording medium 11 is further increased. can do. Note that the above-mentioned member 42 may be made movable depending on the magnetic field strength.
次に、第5図を参照して本発明の他の実施例を説明する
。第5図の実施例において、光ピックアップ装置51の
磁気回路は第1図と同様であるが、光ピツクアップ装置
51の記録媒体11に面した側の磁気回路近傍に強磁性
体の部材52およびその支持部材53を配置している。Next, another embodiment of the present invention will be described with reference to FIG. In the embodiment of FIG. 5, the magnetic circuit of the optical pickup device 51 is the same as that of FIG. 1, but a ferromagnetic member 52 and its A support member 53 is arranged.
これにより、磁気回路から漏れた漏洩磁束は強磁性体部
材52を磁化し、さらに記録媒体11に強磁性体部材5
2により磁界を付与することができる。As a result, the leakage magnetic flux leaked from the magnetic circuit magnetizes the ferromagnetic member 52, and furthermore, the ferromagnetic member 52 is attached to the recording medium 11.
2 can apply a magnetic field.
なお、前述の実施例では記録時を例にして説明したが、
本発明は少なくとも記録媒体に光ビームを東光させて情
報の消去を行う光ピツクアップにも適用することができ
、その場合にも、簡単な構成で記録媒体の情報を消去す
る方向に補助磁界を付与することができる。In addition, although the above-mentioned embodiment was explained using recording as an example,
The present invention can be applied to at least an optical pickup in which information is erased by directing a light beam onto a recording medium, and even in that case, an auxiliary magnetic field is applied in the direction of erasing information on the recording medium with a simple configuration. can do.
効果
以上説明したように、本発明によれば、光ピツクアップ
装置の磁気回路から出る漏洩磁束を記録媒体上にまで誘
導する突起部を磁気回路の一部に設けたので、電磁石等
の磁界付与手段を別番と設けることなく、情報記録時ま
たは消去時に記録媒体に対して必要な磁界をかけること
ができ、その結果、光ヘツド部の軽量小型化が達成でき
て、かつ発熱等の悪影響も除去できるという効果が得ら
れる。Effects As explained above, according to the present invention, a protrusion that guides the leakage magnetic flux emitted from the magnetic circuit of the optical pickup device onto the recording medium is provided in a part of the magnetic circuit. The necessary magnetic field can be applied to the recording medium when recording or erasing information without providing a separate number.As a result, the optical head can be made lighter and smaller, and adverse effects such as heat generation can be eliminated. You can get the effect that you can.
第1図および第2図はそれぞれ従来装置の構成例を示す
縦断面図、第3図は本発明装置の構成例を示す縦断面図
、第4図は本発明装置の他の構成例゛を示す縦断面図、
第5図は本発明装置の他の構成例を示す縦断面図である
。
1.31,41.51・・・光ピツクアップ装置、2・
・・対物レンズ、□
3・・・鏡筒、
4a、4b・・・弾性支持体、
5・・・筐体、
6・・・駆動コイル、
7a、7b・・・ヨーク、
8・・・永久磁石、
9・・・カル7へ7ミラー、
10・・・光ビーム、
11・・・記録媒体、
12・・・電磁石、
12a・・・磁界H4装置、
13 、13a・・・強磁性体部材、
14 、14a・・・コイル、
32・・・強磁性体突起部、
33・・・晶洩磁束、
42.52・・・強磁性体部材、
53・・・女手1811材。
特 許 出 願 人 キャノン株式会社第1図
0
第2図
第3図1 and 2 are longitudinal sectional views showing an example of the configuration of a conventional device, FIG. 3 is a longitudinal sectional view showing an example of the configuration of the device of the present invention, and FIG. 4 is a longitudinal sectional view of another example of the configuration of the device of the present invention. A longitudinal cross-sectional view showing,
FIG. 5 is a longitudinal sectional view showing another example of the configuration of the device of the present invention. 1.31, 41.51... Optical pickup device, 2.
...Objective lens, □ 3... Lens barrel, 4a, 4b... Elastic support, 5... Housing, 6... Drive coil, 7a, 7b... Yoke, 8... Permanent Magnet, 9...7 mirror to Cal 7, 10...Light beam, 11...Recording medium, 12...Electromagnet, 12a...Magnetic field H4 device, 13, 13a...Ferromagnetic member , 14 , 14a... Coil, 32... Ferromagnetic protrusion, 33... Crystal leakage magnetic flux, 42.52... Ferromagnetic member, 53... Female hand 1811 material. Patent applicant: Canon Co., Ltd. Figure 1 0 Figure 2 Figure 3
Claims (1)
ツクアップ装置を用いて光ビームを集光して照射するこ
とにより少なくとも情報の記録ま牟は消去を行う装置に
おいて、前記光学系誓誕を所定方向に変位させる電磁的
駆動手段を構成する磁気回路から出る漏洩磁束を前記記
録媒体へ補助磁界として導く磁気誘導手段を設けたこと
を特徴とする光ピツクアップ装置。 2、特許請求の範囲第1項記戦の装置市において、前記
磁気誘導手段は、対物レンズを駆動する前記磁気回路の
一部分から前記記録媒体に対向して突設した強磁性体で
あることを特徴とする光ピンクアップ装置。[Scope of Claims] 1) A device for erasing at least information recorded by condensing and irradiating a light beam on a recording medium made of a magnetic thin film using an optical pickup device having an optical system, An optical pickup device comprising: a magnetic guide means for guiding leakage magnetic flux from a magnetic circuit constituting an electromagnetic drive means for displacing the optical system in a predetermined direction to the recording medium as an auxiliary magnetic field. 2. In the apparatus set forth in claim 1, it is provided that the magnetic induction means is a ferromagnetic material protruding from a part of the magnetic circuit that drives the objective lens and facing the recording medium. Features optical pink-up device.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP58025495A JPS59152503A (en) | 1983-02-19 | 1983-02-19 | Optical pickup device |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP58025495A JPS59152503A (en) | 1983-02-19 | 1983-02-19 | Optical pickup device |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS59152503A true JPS59152503A (en) | 1984-08-31 |
JPH0232692B2 JPH0232692B2 (en) | 1990-07-23 |
Family
ID=12167637
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP58025495A Granted JPS59152503A (en) | 1983-02-19 | 1983-02-19 | Optical pickup device |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS59152503A (en) |
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0115666A2 (en) * | 1983-01-25 | 1984-08-15 | Sharp Kabushiki Kaisha | Optical focus position control in optical disc apparatus |
EP0122816A2 (en) * | 1983-04-18 | 1984-10-24 | Sharp Kabushiki Kaisha | Optical focus position control in an optical memory system |
JPS60170048A (en) * | 1984-02-15 | 1985-09-03 | Hitachi Ltd | Photomagnetic memory device |
JPS613504U (en) * | 1984-06-14 | 1986-01-10 | ソニー株式会社 | magneto-optical recording device |
JPS6417201A (en) * | 1987-07-09 | 1989-01-20 | Nec Corp | Electromagnet for impressing magnetic field for magneto-optical disk |
JPH01178106A (en) * | 1988-01-06 | 1989-07-14 | Nec Corp | Magnetic field device for magneto-optical disk |
JPH01178107A (en) * | 1988-01-08 | 1989-07-14 | Nec Corp | Magnetic field device for magneto-optical disk |
JPH01178104A (en) * | 1988-01-05 | 1989-07-14 | Nec Corp | Magnetic field electromagnet for magneto-optical disk |
EP0383526A2 (en) * | 1989-02-16 | 1990-08-22 | Minnesota Mining And Manufacturing Company | Magneto-optic recording system |
JPH0332731U (en) * | 1989-08-08 | 1991-03-29 |
-
1983
- 1983-02-19 JP JP58025495A patent/JPS59152503A/en active Granted
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0115666A2 (en) * | 1983-01-25 | 1984-08-15 | Sharp Kabushiki Kaisha | Optical focus position control in optical disc apparatus |
EP0122816A2 (en) * | 1983-04-18 | 1984-10-24 | Sharp Kabushiki Kaisha | Optical focus position control in an optical memory system |
JPS60170048A (en) * | 1984-02-15 | 1985-09-03 | Hitachi Ltd | Photomagnetic memory device |
JPS613504U (en) * | 1984-06-14 | 1986-01-10 | ソニー株式会社 | magneto-optical recording device |
JPH0422403Y2 (en) * | 1984-06-14 | 1992-05-22 | ||
JPS6417201A (en) * | 1987-07-09 | 1989-01-20 | Nec Corp | Electromagnet for impressing magnetic field for magneto-optical disk |
JPH01178104A (en) * | 1988-01-05 | 1989-07-14 | Nec Corp | Magnetic field electromagnet for magneto-optical disk |
JPH01178106A (en) * | 1988-01-06 | 1989-07-14 | Nec Corp | Magnetic field device for magneto-optical disk |
JPH01178107A (en) * | 1988-01-08 | 1989-07-14 | Nec Corp | Magnetic field device for magneto-optical disk |
EP0383526A2 (en) * | 1989-02-16 | 1990-08-22 | Minnesota Mining And Manufacturing Company | Magneto-optic recording system |
JPH0332731U (en) * | 1989-08-08 | 1991-03-29 |
Also Published As
Publication number | Publication date |
---|---|
JPH0232692B2 (en) | 1990-07-23 |
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