JPH03241553A - Magnetic field application device for optical disk device - Google Patents

Abstract

PURPOSE:To correct an impression magnetic field to that within a specified range by providing a magnet which is make opposite to a recording type optical disk surface and made freely rotatable around the rotary shaft parallel to the disk surface, and setting the rotary shaft to be eccentric in a state where an eccentricity quantity can freely be adjusted to a magnetic pole. CONSTITUTION:The rotary shaft 11 of the magnet 8 is set to be eccentric as against the magnetic pole and an N-pole-side is set to be far from the magneto-optical disk DI1 surface from the center of the magnet 8. The strength of the magnetic field impressed from the magnet 8 on the DI1 surface is weak at the time of recording and it becomes strong at the time of elimination as shown in a broken line C. A leakage magnetic field 10 owing to the actuator 5 of an optical pickup 3 operates so that the strength of the magnetic field is increased at the time of recording and it is decreased at the time of elimination when the polarity is set to be an N-pole. Thus, the eccentricity quantity of the shaft 11 is set to be freely adjustable structure and a distance between DI1 surface and the magnetic pole is suitably set. Thus, the leakage magnetic field 10 is compensation-cancelled and it can be corrected to the impression magnetic field stored within the specified range at the time of recording and elimination as shown as a solid line D on the DI1 surface.

Description

【発明の詳細な説明】 産業上の利用分野 本発明は、光磁気ディスク等の記録型光ディスクを用い
た光ディスク装置の磁界印加装置に関する。DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic field applying device for an optical disk device using a recording type optical disk such as a magneto-optical disk.

従来の技術 第５図は光磁気記録方式の原理を説明するためのもので
、まず、光磁気ディスク１はその記録面にＣｄＣｏ、Ｆ
ｅＴｅ等の薄膜を設けてなる。このような光磁気ディス
ク１に対して磁界印加装置２により外部磁界を印加した
状態で、反対面側より光ピツクアップ３（対物レンズ４
とアクチュエータ５で代表する）によりレーザ光を照射
する。Conventional technology FIG. 5 is for explaining the principle of the magneto-optical recording system. First, a magneto-optical disk 1 has a recording surface coated with CdCo, F
A thin film of eTe or the like is provided. While an external magnetic field is applied to such a magneto-optical disk 1 by a magnetic field applying device 2, an optical pickup 3 (objective lens 4) is applied from the opposite side.
(represented by actuator 5) irradiates laser light.

このレーザ光照射により熱の加わった部分は、保持力が
落ち、磁界印加装置２による外部磁界の向きに磁化６が
反転する。この磁化６の向きによって１１１　＃かｌ　
Ｑ　ｌ″の情報を記録するというものである。The coercive force of the portion heated by this laser beam irradiation decreases, and the magnetization 6 is reversed in the direction of the external magnetic field from the magnetic field application device 2. Depending on the direction of this magnetization 6, 111 # or l
This is to record the information of Q1''.

ここに、光磁気ディスク１の記録膜に印加する外部磁界
の向きを変える方法として、第６図に示すように、ディ
スク面に平行な回転軸７（紙面表裏方向に伸びている）
を中心に回動自在に磁石８を設け、周囲のコイル９への
通電制御により回転させ、Ｓ極とＮ極とを切換えるよう
にしたものが実用化されている。Here, as a method of changing the direction of the external magnetic field applied to the recording film of the magneto-optical disk 1, as shown in FIG.
A magnet 8 has been put into practical use so as to be rotatable around the center, and is rotated by controlling the energization of the surrounding coil 9 to switch between the south pole and the north pole.

発明が解決しようとする課題 このような記録方式において、記録又は消去を確実に行
なうためには、記録膜に印加される外部磁界強度が記録
・消去時の何れの場合にあっても特定の範囲内におさま
っていることが必要である。Problems to be Solved by the Invention In such a recording system, in order to ensure recording or erasing, the intensity of the external magnetic field applied to the recording film must be within a specific range, whether during recording or erasing. It is necessary to stay within.

例えば、ＩＳＯ標準化委員会（３，５インチ）によれば
、記録時：＋２００〜＋４００［Ｏｅｌ、消去時ニー２
００〜−４００　［Ｏｅｌのように磁界強度が指定され
ている。記録及び消去時の印加磁界の強度がこのような
特定の範囲内にない場合、記録膜でのビット（マーク）
の形成のバラツキを生じ、誤記録や誤再生の原因ともな
る。For example, according to the ISO standardization committee (3.5 inches), recording: +200 to +400 [Oel, erasing knee 2
00 to -400 [Magnetic field strength is specified as Oel. If the strength of the applied magnetic field during recording and erasing is not within such a specific range, bits (marks) on the recording film
This causes variations in the formation of the discs, causing erroneous recording and erroneous playback.

この点、第６図のものを検討すると、回転軸７が磁石８
の磁極中心（Ｎ極とＳ極の中間）にあるため、光ピツク
アップ３側のアクチュエータ５からの漏れ磁界１０が生
じたとすると、光磁気ディスク１面上の磁界強度は記録
時と消去時とで異なってくる。よって、上記の範囲を越
える場合を生ずる。Regarding this point, when considering the one in FIG. 6, it is found that the rotating shaft 7 is
Assuming that a leakage magnetic field 10 is generated from the actuator 5 on the optical pickup 3 side, the magnetic field strength on the surface of the magneto-optical disk 1 differs between recording and erasing. It will be different. Therefore, there may be cases where the above range is exceeded.

第７図は第６図構成による場合の記録時／消去時の磁界
印加の様子を示すものである。ここに、仮に記録時−の
印加磁界をＮ極、消去時の印加磁界をＳ極、光ピツクア
ップ３のアクチュエータ５による漏れ磁界の極性をＮ極
とする。すると、光磁気ディスク１面上に実際に印加さ
れる磁界強度は、磁石８からの磁界のみであれば同図（
ｂ）中に破線Ａで示すような磁界強度となるが、漏れ磁
界１０のため、実際には実線Ｂで示すような強度磁界と
なり、Ｎ極のほうが大きくなる。つまり、記録時の印加
磁界が消去時よりも大きくなる。この結果、上記のよう
な不都合を生じ得る。FIG. 7 shows how a magnetic field is applied during recording/erasing in the case of the configuration shown in FIG. 6. Here, it is assumed that the magnetic field applied during recording is N pole, the magnetic field applied during erasing is S pole, and the polarity of the leakage magnetic field by actuator 5 of optical pickup 3 is N pole. Then, if the magnetic field strength actually applied to the surface of the magneto-optical disk is only the magnetic field from the magnet 8, the intensity is as shown in the figure (
In b), the magnetic field intensity is as shown by the broken line A, but due to the leakage magnetic field 10, the magnetic field is actually as strong as shown by the solid line B, and the north pole is larger. In other words, the applied magnetic field during recording becomes larger than during erasing. As a result, the above-mentioned disadvantages may occur.

課題を解決するための手段 記録型光ディスク面に対向させてディスク面に平行な回
転軸を中心に回転自在な磁石を備えた光ディスク装置の
磁界印加装置において、前記回転軸を磁極に対して偏心
量調整自在な状態に偏心させて設けた。Means for Solving the Problems In a magnetic field application device for an optical disk device, which is equipped with a magnet that faces the surface of a recording type optical disk and is rotatable about a rotation axis that is parallel to the disk surface, the amount of eccentricity of the rotation axis with respect to the magnetic pole is determined. It is set eccentrically so that it can be adjusted freely.

作用 磁石の回転軸が磁極に対して偏心しているため、記録用
、消去用の各々の磁極と記録型光ディスク面との距離が
異なることになり、各々の磁極によりディスク面上に印
加される磁界強度に差を持たせることができる。よって
、この磁界強度の差、即ち、回転軸の偏心量を調整し、
光ピツクアップ側による漏れ磁界をキャンセルする大き
さとすることにより、ディスク面上で記録時、消去時の
何れの場合も特定範囲内に収まる印加磁界となるように
補正することができる。Since the rotation axis of the working magnet is eccentric with respect to the magnetic poles, the distances between the recording and erasing magnetic poles and the recording optical disk surface are different, and the magnetic field applied to the disk surface by each magnetic pole is It is possible to make a difference in strength. Therefore, by adjusting the difference in magnetic field strength, that is, the amount of eccentricity of the rotating shaft,
By setting the magnitude to cancel the leakage magnetic field from the optical pickup side, it is possible to correct the applied magnetic field so that it falls within a specific range both during recording and erasing on the disk surface.

実施例 本発明の第一の実施例を第１図ないし第３図に基づいて
説明する。第５図ないし第７図で示した基本構成はその
まま用いるものとする。本実施例は、基本的には、第１
図（ａ）に示すように、磁石８の回転軸１１をその磁極
に対して偏心させて設けたものである。本実施例は、第
７図の例を想定しており、回転軸１１を磁石８の中心か
ら、光磁気ディスク１面に対しＮ極側が遠くなるように
ずらしたものである。Embodiment A first embodiment of the present invention will be described with reference to FIGS. 1 to 3. The basic configuration shown in FIGS. 5 to 7 will be used as is. This embodiment basically consists of the first
As shown in Figure (a), the rotating shaft 11 of the magnet 8 is eccentrically provided with respect to its magnetic pole. In this embodiment, the example shown in FIG. 7 is assumed, and the rotating shaft 11 is shifted from the center of the magnet 8 so that the north pole side is farther away from the surface of the magneto-optical disk.

このような構成によれば、磁石８によって光磁気ディス
ク１面に印加される磁界の強さは、同図（ｂ）中に破線
Ｃで示すように、記録時に弱く、消去時に強くなる。ま
た、光ピツクアップ３のアクチュエータ５による漏れ磁
界の極性をＮ極とすると、漏れ磁界１０で示すように記
録時には磁界の強さを増し、消去時には減らすように働
く。よって、回転軸１１の偏心量を適切に設定すること
により、実線りで示すように、記録時と消去時とのディ
スク面上での印加磁界が等しくなるように補償できる。According to such a configuration, the strength of the magnetic field applied to the surface of the magneto-optical disk by the magnet 8 is weak during recording and becomes strong during erasing, as shown by the broken line C in FIG. 2(b). Furthermore, if the polarity of the leakage magnetic field generated by the actuator 5 of the optical pickup 3 is N-pole, the strength of the magnetic field increases during recording and decreases during erasing, as shown by the leakage magnetic field 10. Therefore, by appropriately setting the amount of eccentricity of the rotating shaft 11, it is possible to compensate so that the magnetic fields applied on the disk surface during recording and erasing are equal, as shown by the solid line.

ところで、前記回転軸１１の偏心量は調整自在とするの
がよい。ここでは、磁石８の磁極間にＮ極寄りに形成し
た軸穴用の長穴１２と回転軸１１との組合せにより、記
録時と消去時とで回転軸１１が偏心した位置となるよう
にしたものである。Incidentally, it is preferable that the amount of eccentricity of the rotating shaft 11 is adjustable. Here, the combination of the rotary shaft 11 and the long hole 12 for the shaft hole formed between the magnetic poles of the magnet 8 closer to the N pole allows the rotary shaft 11 to be in an eccentric position during recording and erasing. It is something.

つまり、長穴１２の大きさ（長さ）が偏心量を規制する
ことになるので、この大きさを第３図中に破線で示すよ
うに適宜設定することにより、ディスク面と磁極との間
の距離を調整し、漏れ磁界１０の補償キャンセルが可能
となる。In other words, the size (length) of the elongated hole 12 regulates the amount of eccentricity, so by setting this size appropriately as shown by the broken line in Figure 3, the distance between the disk surface and the magnetic pole is It is possible to compensate and cancel the leakage magnetic field 10 by adjusting the distance.

また、本発明の第二の実施例を第４図により説明する。Further, a second embodiment of the present invention will be explained with reference to FIG.

本実施例は、回転軸１４の偏心量を可変調整自在とした
ものである。まず、回転軸１４に対する軸穴用の長穴１
５を長めに形成しておき、この長穴１５内での回転軸１
４の位置を規制する先端半円状の微調整ねじ１６を磁石
８に対して微調整自在に取付けるとともに、反対側から
回転軸１４を微調整ねじ１６先端に押付ける押圧ばね１
７を設けたものである。よって、回転軸１４の偏心位置
は微調整ねじ１６により決定されることになる。これに
よれば、光ピツクアップ３のアクチュエータ５側からの
漏れ磁界１０の強度にバラツキがある場合、磁界印加装
置の組付は時にこの微調整ねじ１６を微調することによ
り、バラツキを含めて補償できることになる。In this embodiment, the amount of eccentricity of the rotating shaft 14 can be variably adjusted. First, the elongated hole 1 for the shaft hole for the rotating shaft 14
5 is formed to be long, and the rotation axis 1 in this elongated hole 15 is
A fine adjustment screw 16 with a semicircular tip for regulating the position of the screw 1 is attached to the magnet 8 for fine adjustment, and a pressing spring 1 presses the rotating shaft 14 against the tip of the fine adjustment screw 16 from the opposite side.
7. Therefore, the eccentric position of the rotating shaft 14 is determined by the fine adjustment screw 16. According to this, if there is variation in the strength of the leakage magnetic field 10 from the actuator 5 side of the optical pickup 3, the variation can be compensated for by sometimes finely adjusting the fine adjustment screw 16 when assembling the magnetic field application device. become.

発明の効果 本発明は、上述したように磁石の回転軸を磁極に対して
偏心させ、かつ、偏心量調整自在に設けて、記録用、消
去用の各々の磁極によりディスク面上に印加される磁界
強度に差を持たせたので、磁界強度の差、即ち、偏心量
を、光ピツクアップ側による漏れ磁界をキャンセルする
大きさとすることにより、ディスク面上で記録時、消去
時の何れの場合も特定範囲内に収まる印加磁界となるよ
うに補正することができる。Effects of the Invention As described above, the present invention makes the rotating shaft of the magnet eccentric with respect to the magnetic poles, and the eccentricity is adjustable, so that the magnetic poles for recording and erasing can apply voltage onto the disk surface. Since there is a difference in magnetic field strength, the difference in magnetic field strength, that is, the amount of eccentricity, is set to a size that cancels the leakage magnetic field from the optical pickup side. The applied magnetic field can be corrected to fall within a specific range.

【図面の簡単な説明】[Brief explanation of drawings]

第１図は本発明の第一の実施例を示す記録／消去時の磁
界強度関係を示す説明図、第２図はその偏心量調整手段
を示す磁石の正面図、第３図はその一部を拡大した正面
図、第４図は本発明の第二の実施例を示す磁石の正面図
、第５図は一般的な光磁気記録方式の原理を示す概略構
成図、第６図はより具体的に示す概略構成図、第７図は
従来例による記録／消去時の磁界強度関係を示す説明図
である。 １・・・記録型光ディスク、８・・・磁石、１１，１３
゜１４・・・回転軸 出　願　人　　　株式会社　　　リ　コ、７）１４図 １ ７焔FIG. 1 is an explanatory diagram showing the magnetic field strength relationship during recording/erasing according to the first embodiment of the present invention, FIG. 2 is a front view of the magnet showing the eccentricity adjusting means, and FIG. 3 is a part thereof. FIG. 4 is a front view of a magnet showing the second embodiment of the present invention, FIG. 5 is a schematic configuration diagram showing the principle of a general magneto-optical recording system, and FIG. 6 is a more specific diagram. FIG. 7 is an explanatory diagram showing the magnetic field strength relationship during recording/erasing according to a conventional example. 1... Recordable optical disk, 8... Magnet, 11, 13
゜14... Rotating shaft applicant Rico Co., Ltd., 7) 14 Figure 1 7 Flame

Claims (1)

【特許請求の範囲】[Claims] 　記録型光ディスク面に対向させてディスク面に平行な
回転軸を中心に回転自在な磁石を備えた光ディスク装置
の磁界印加装置において、前記回転軸を磁極に対して偏
心量調整自在な状態に偏心させて設けたことを特徴とす
る光ディスク装置の磁界印加装置。In a magnetic field application device for an optical disk device, which includes a magnet that faces a recording type optical disk surface and is rotatable about a rotating shaft parallel to the disk surface, the rotating shaft is eccentrically adjusted with respect to a magnetic pole so that the amount of eccentricity can be freely adjusted. What is claimed is: 1. A magnetic field applying device for an optical disk device, characterized in that the device is provided with a magnetic field applying device.