JPH0775041B2 - Bias magnetic field supply device - Google Patents
Bias magnetic field supply deviceInfo
- Publication number
- JPH0775041B2 JPH0775041B2 JP63011171A JP1117188A JPH0775041B2 JP H0775041 B2 JPH0775041 B2 JP H0775041B2 JP 63011171 A JP63011171 A JP 63011171A JP 1117188 A JP1117188 A JP 1117188A JP H0775041 B2 JPH0775041 B2 JP H0775041B2
- Authority
- JP
- Japan
- Prior art keywords
- yoke
- magnetic field
- recording area
- length
- bias magnetic
- 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
- G11B11/10534—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
Description
【発明の詳細な説明】 産業上の利用分野 本発明は、光磁気ディスク装置において、光磁気ディス
ク（以下、ディスクと称す）の半径方向の記録領域に磁
界を供給する装置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for supplying a magnetic field to a radial recording area of a magneto-optical disk (hereinafter referred to as a disk) in a magneto-optical disk apparatus.
従来の技術 従来のバイアス磁界供給装置は、第６図に示すように、
ディスクＤにおける半径方向の記録領域の長さ（以下、
記録長と称す）に対応する長さの長円形の断面形状を有
するセンターヨーク31を備え、このセンターヨーク31の
周囲にコイル32を配置するとともに、コイル32の外周お
よびディスクＤとは反対側の側面をヨーク33で囲んだ電
磁石34が用いられ、この電磁石34をディスクＤに対して
適当な間隙Ｇをあけて位置させ得るように構成されてい
た。2. Description of the Related Art A conventional bias magnetic field supply device, as shown in FIG.
The length of the recording area in the radial direction on the disk D (hereinafter,
A center yoke 31 having an oval cross-sectional shape with a length corresponding to the recording length) is provided, a coil 32 is arranged around the center yoke 31, and the outer periphery of the coil 32 and the side opposite to the disk D are provided. An electromagnet 34 whose side surface is surrounded by a yoke 33 is used, and the electromagnet 34 can be positioned with a proper gap G with respect to the disk D.
発明が解決しようとする課題 ところが、上記のようにヨーク長が記録長にほぼ対応し
た構成では、第７図に示すように、例えばヨーク端面と
記録面の間のギャップが0.5mmと小さい状態では、ヨー
ク両端に磁束密度が集中するエッジ効果が大きく現れ、
記録領域の両端部で斜線で示すようにディスクの許容最
大磁束密度（例えば600ガウス）を越える部分を生ずる
という問題があった。However, in the configuration in which the yoke length substantially corresponds to the recording length as described above, when the gap between the yoke end surface and the recording surface is as small as 0.5 mm, as shown in FIG. , The edge effect that the magnetic flux density is concentrated on both ends of the yoke appears significantly,
There is a problem that a portion exceeding the maximum permissible magnetic flux density (for example, 600 gauss) of the disc is generated at both ends of the recording area as shown by diagonal lines.
逆に、ギャップが例えば1.5mmと大きい状態では、破線
で示すように中央部ではディスクの許容最小磁束密度
（例えば300ガウス）に達していても記録領域の両端部
では達せず、そのため電流値を上げて実線で示す磁束密
度分布とすることが必要になるが、そうすると発熱量が
大きくなるという問題があった。On the contrary, when the gap is as large as 1.5 mm, for example, as shown by the broken line, even if the minimum allowable magnetic flux density of the disk (for example, 300 gauss) is reached in the central portion, it is not reached in both end portions of the recording area, so that the current value It is necessary to raise the magnetic flux density distribution as shown by the solid line, but this causes a problem that the amount of heat generation increases.
本発明は、上記従来の問題点に鑑み、磁束密度の分布を
記録長の範囲内で平滑化して、ギャップが変化しても磁
束密度分布がディスクの許容範囲に納まるようにしたバ
イアス磁界供給装置の提供を目的とする。In view of the above conventional problems, the present invention smoothes the distribution of the magnetic flux density within the range of the recording length so that the magnetic flux density distribution is within the allowable range of the disk even if the gap changes. For the purpose of providing.
課題を解決するための手段 本発明は上記目的を達成するため、光磁気ディスク装置
におけるディスクの半径方向の記録領域に電磁石にてバ
イアス磁界を供給する装置において、前記電磁石のヨー
クの前記記録領域と対向する部分の両端部を広幅にした
ことを特徴とする。Means for Solving the Problems In order to achieve the above object, the present invention provides an apparatus for supplying a bias magnetic field to a recording area in a radial direction of a disk in a magneto-optical disk apparatus by using an electromagnet, and the recording area of a yoke of the electromagnet. It is characterized in that both ends of the facing portion are widened.
なお、前記ヨークの記録領域と対向する部分はセンター
ヨークの先端部、もしくは記録領域の長さに比べて小さ
い径のセンターヨークの先端に設けた先端ヨークから成
る。The portion of the yoke facing the recording area is formed by the tip portion of the center yoke or the tip yoke provided at the tip of the center yoke having a diameter smaller than the length of the recording area.
作用 本発明の上記構成によれば、ヨーク記録領域に対向する
部分の両端部を広幅としたことによってエッジ効果が低
減され、最小ギャップ時にヨークの両端部における磁束
密度がディスクの許容範囲を越えないようにすることが
できる。According to the above configuration of the present invention, the edge effect is reduced by widening both ends of the portion facing the yoke recording area, and the magnetic flux density at both ends of the yoke does not exceed the allowable range of the disk at the minimum gap. You can
実施例 以下、本発明の一実施例を第１図〜第３図を参照しなが
ら説明する。Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.
まず、第３図により光磁気ディスク装置１の全体構成を
説明する。２は、光磁気ディスク（以下ディスクと称
す）で、カートリッジ３内に収容された状態でセットさ
れ、中央の支持部４がスピンドル５の上端に設けられた
回転伝達部６にて支持される。７は前記回転伝達部４に
固定されたディスク吸着用の磁石、８はディスク３の支
持部４に設けられたディスク３の位置決め及び吸着用の
位置決め板である。前記スピンドル５の下部にはこれを
回転駆動するモータ９が配設され、そのロータ10にスピ
ンドル５の下端が固定されている。First, the overall configuration of the magneto-optical disk device 1 will be described with reference to FIG. Reference numeral 2 denotes a magneto-optical disk (hereinafter referred to as a disk), which is set in a state of being housed in a cartridge 3, and a central supporting portion 4 is supported by a rotation transmitting portion 6 provided on an upper end of a spindle 5. Reference numeral 7 is a magnet for attracting the disk, which is fixed to the rotation transmitting portion 4, and reference numeral 8 is a positioning plate for positioning and attracting the disk 3, which is provided on the support portion 4 of the disk 3. A motor 9 for rotationally driving the spindle 5 is arranged below the spindle 5, and a lower end of the spindle 5 is fixed to a rotor 10 of the motor 9.
11は、前記ディスク２の記録膜12に光を当てて記録又は
再生を行うピックアップ装置であり矢印Ａの如くディス
ク２の半径方向に移動可能に構成されている。また、デ
ィスク２を間に挟んでピックアップ装置11の反対側にバ
イアス磁界供給装置20が配設され、セット状態のディス
ク２の記録膜12に対して所定のギャップをあけて位置し
得るように矢印Ｂの如く上下動可能に支持されている。Reference numeral 11 is a pickup device for irradiating the recording film 12 of the disk 2 with light for recording or reproduction, and is configured to be movable in the radial direction of the disk 2 as indicated by an arrow A. Further, a bias magnetic field supplying device 20 is arranged on the opposite side of the pickup device 11 with the disc 2 interposed therebetween, and an arrow mark is provided so that the bias magnetic field supplying device 20 can be positioned with a predetermined gap with respect to the recording film 12 of the set disc 2. Like B, it is supported so that it can move up and down.
前記バイアス磁界供給装置20においては、第１図に示す
ように、記録長に比して径の小さい丸軸状のセンターヨ
ーク21の周囲にコイル22が巻回されている。このコイル
22のディスク２側の一側は開放され、外周と他側はヨー
ク23の周壁23aと底壁23bにて囲まれている。このヨーク
23の底壁23bと前記センターヨーク21の基端部は互いに
係合されている。前記センターヨーク21の先端には、第
２図に示すように、記録長に対応する長さより両端にl1
＝0.5〜1.0mmだけ長く、かつ両端部に広幅部25を形成し
た細幅の先端ヨーク24が一体的に設けられているこうし
て、センターヨーク21から先端ヨーク24を通って外部に
出た後、ヨーク周壁23aに入り、ヨーク底壁23bを経てセ
ンターヨーク21に戻る磁気回路を有する電磁石26が構成
されている。In the bias magnetic field supply device 20, as shown in FIG. 1, a coil 22 is wound around a round shaft-shaped center yoke 21 having a diameter smaller than the recording length. This coil
One side of the disc 2 on the disk 2 side is open, and the outer periphery and the other side are surrounded by a peripheral wall 23a and a bottom wall 23b of the yoke 23. This york
The bottom wall 23b of 23 and the base end of the center yoke 21 are engaged with each other. The tip of the center yoke 21, as shown in FIG. 2, l 1 at both ends than the length corresponding to the record length
= 0.5 to 1.0 mm long, and the narrow width front end yoke 24 having the wide width portions 25 formed at both ends is integrally provided in this way. An electromagnet 26 having a magnetic circuit that enters the yoke peripheral wall 23a and returns to the center yoke 21 via the yoke bottom wall 23b is configured.
以上の構成によると、先端ヨーク24を設けているため、
センターヨーク21の径を小さくしても記録長の全長に磁
界を供給できる。従って、センターヨーク21の径を小さ
くできることに伴ってコイル22が小さくなり、電磁石25
の全体を著しく小型化でき、そのためにコイル22の線長
が短くなり、抵抗による発熱量も低減することができ
る。According to the above configuration, since the tip yoke 24 is provided,
Even if the diameter of the center yoke 21 is reduced, the magnetic field can be supplied over the entire recording length. Therefore, the coil 22 becomes smaller as the diameter of the center yoke 21 becomes smaller, and the electromagnet 25 becomes smaller.
Can be remarkably miniaturized, the wire length of the coil 22 can be shortened, and the amount of heat generated by resistance can be reduced.
しかも、第２図に示すように、先端ヨーク24の長さを記
録長よりも若干長く設定しているため例えばギャップが
1.5mmの最大ギャップ時における磁束密度分布は、仮想
線で示す従来のように記録長の両端部で、例えば300ガ
ウスという許容最小磁束密度に達しないというようなこ
とはなく、実線で示すように両端部と中央部が共に許容
最小磁束密度に達する。Moreover, as shown in FIG. 2, since the length of the tip yoke 24 is set to be slightly longer than the recording length, for example, the gap is
The magnetic flux density distribution at the maximum gap of 1.5 mm does not always reach the allowable minimum magnetic flux density of, for example, 300 Gauss at both ends of the recording length as shown by the phantom line, as shown by the solid line. Both end portions and the central portion reach the allowable minimum magnetic flux density.
また、先端ヨーク24の両端部に、広幅部25を形成してい
るので、例えばギャップが0.5mmの最小ギャップ時にお
いてエッジ効果が著しく低減されるため、仮想線で示す
従来のように記録長の両端部で、例えば600ガウスとい
う許容最大磁束密度を越えてしまうというようなことは
なく実線で示すように記録長の両端部でも許容最大磁束
密度を越えることはない。Further, since the wide width portions 25 are formed at both end portions of the tip yoke 24, the edge effect is remarkably reduced when the gap is the minimum gap of 0.5 mm. At both ends, the maximum allowable magnetic flux density of, for example, 600 gauss is not exceeded, and as shown by the solid line, the maximum allowable magnetic flux density is not exceeded at both ends of the recording length.
上記実施例では先端ヨーク24を若干長く形成するととも
に両端部に広幅部25を設けた例を示したが、いずれか一
方のみであってもそれぞれの効果は発揮する。In the above-described embodiment, the tip yoke 24 is formed to be slightly long and the wide portions 25 are provided at both ends, but the respective effects are exhibited even if only one of them is provided.
次に、第４図に基づいて第２実施例を説明するこの第２
実施例では先端ヨーク24の長さが、記録長に対応する長
さより両端にl2＝1.0〜3.0mmだけ長く形成されている。Next, the second embodiment will be described with reference to FIG.
In the embodiment, the length of the tip yoke 24 is formed longer than the length corresponding to the recording length by l 2 = 1.0 to 3.0 mm at both ends.
このような構成によると、ギャップが0.5mmの最小ギャ
ップ時において、エッジ効果による高い磁束密度の部分
が、第４図に実線で示すように記録長の範囲の外側にＣ
の如く大きく変位するため、記録長の範囲では、例えば
600ガウスという許容最大磁束密度より小さい磁束密度
分布となり、仮想線で示す従来のように記録長の両端部
で許容最大磁束密度を越えるということはない。With such a structure, at the minimum gap of 0.5 mm, the portion of high magnetic flux density due to the edge effect is C outside the range of the recording length as shown by the solid line in FIG.
As shown in Fig.
The magnetic flux density distribution is 600 Gauss, which is smaller than the maximum allowable magnetic flux density, and the maximum allowable magnetic flux density does not exceed the maximum allowable magnetic flux density at both end portions of the recording length as shown by the phantom line.
また、ギャップが1.5mmの最大ギャップ時における磁束
密度分布は、記録長の中央部で300ガウスという許容最
大磁束密度に丁度達した状態では、記録長の両端部では
許容最大磁束密度を余裕をもって越え、この許容最小磁
束密度に達する位置が記録長の外側へＤの如く変位して
いるためその分余裕を見込むことができる。In addition, the magnetic flux density distribution at the maximum gap of 1.5 mm has a margin to exceed the maximum allowable magnetic flux density at both ends of the recording length when the maximum allowable magnetic flux density of 300 Gauss is reached at the center of the recording length. However, since the position where the allowable minimum magnetic flux density is reached is displaced to the outside of the recording length by D, a margin can be expected accordingly.
さらに、上記各実施例において、第５図に示すように、
先端ヨーク24の両端に平面状もしくはアール状の面取27
を形成すると、エッジ効果を一層低減することができて
さらに効果を高めることができる。Further, in each of the above embodiments, as shown in FIG.
A flat or round chamfer 27 on both ends of the tip yoke 24.
By forming, the edge effect can be further reduced and the effect can be further enhanced.
又、上記各実施例では先端ヨーク24に対して広幅部25を
形成したり、記録長よりも長くした例を示したが、従来
例で示したセンターヨークについて同様の構成を適用し
ても同様の効果を発揮することができる。Further, in each of the above-described embodiments, the wide width portion 25 is formed with respect to the tip yoke 24 or is longer than the recording length, but the same configuration is applied to the center yoke shown in the conventional example. The effect of can be exhibited.
発明の効果 本発明のバイアス磁界供給装置によれば、以上のように
ヨークの記録領域に対向する部分の両端部を広幅とした
ことによってエッジ効果が低減され、最小ギャップ時に
ヨークの両端部における磁束密度がディスクの許容範囲
を越えないようにすることができる。According to the bias magnetic field supply device of the present invention, the edge effect is reduced by widening the both ends of the portion of the yoke facing the recording area as described above, and the magnetic flux at both ends of the yoke at the minimum gap is reduced. It is possible that the density does not exceed the tolerance of the disc.
第１図は本発明の一実施例におけるバイアス磁界供給装
置を示し、同（ａ）は断面図、同（ｂ）は下面図、第２
図は同作用説明図、第３図は同光磁気ディスク装置の要
部の概略構成図、第４図は第２実施例の作用説明図、第
５図は第３実施例の作用説明図、第６図は従来例を示
し、同（ａ）は断面図同（ｂ）は下面図、第７図は同作
用説明図である。 20……バイアス磁界供給装置 21……センターヨーク 22……コイル 24……先端ヨーク 25……広幅部 26……電磁石 27……面取。1A and 1B show a bias magnetic field supply device according to an embodiment of the present invention. FIG. 1A is a sectional view, FIG. 1B is a bottom view, and FIG.
FIG. 4 is an explanatory view of the same operation, FIG. 3 is a schematic configuration diagram of a main part of the same magneto-optical disk device, FIG. 4 is an operation explanatory view of the second embodiment, and FIG. 5 is an operation explanatory view of the third embodiment. FIG. 6 shows a conventional example, FIG. 6 (a) is a sectional view, FIG. 6 (b) is a bottom view, and FIG. 20 …… Bias magnetic field supply device 21 …… Center yoke 22 …… Coil 24 …… Tip yoke 25 …… Wide part 26 …… Electromagnet 27 …… Chamfer.
Claims (3)
径方向の記録領域に電磁石にてバイアス磁界を供給する
装置において、前記電磁石のヨークの前記記録領域と対
向する部分の両端部を広幅にしたことを特徴とするバイ
アス磁界供給装置。1. In an apparatus for supplying a bias magnetic field to a recording area in the radial direction of a disk in a magneto-optical disk apparatus by an electromagnet, both ends of a portion of a yoke of the electromagnet facing the recording area are made wide. Characteristic bias magnetic field supply device.
さに比べて小さくし、前記センターヨークの先端に記録
領域にほぼ対応した長さの先端ヨークを設け、この先端
ヨークの両端部を広幅にした請求項１記載のバイアス磁
界供給装置。2. A center yoke diameter of an electromagnet is made smaller than a length of a recording area, a tip yoke having a length substantially corresponding to the recording area is provided at a tip of the center yoke, and both ends of the tip yoke are widened. The bias magnetic field supply device according to claim 1.
を、記録領域の中央部と両端における磁束密度が最大ギ
ャップ時にほぼ同等となるように、記録領域の長さより
長くした請求項１又は２記載のバイアス磁界供給装置。3. The length of the portion of the yoke facing the recording area is made longer than the length of the recording area so that the magnetic flux densities at the center and both ends of the recording area are substantially equal at the maximum gap. 2. The bias magnetic field supply device according to 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63011171A JPH0775041B2 (en) | 1988-01-21 | 1988-01-21 | Bias magnetic field supply device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63011171A JPH0775041B2 (en) | 1988-01-21 | 1988-01-21 | Bias magnetic field supply device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01185804A JPH01185804A (en) | 1989-07-25 |
| JPH0775041B2 true JPH0775041B2 (en) | 1995-08-09 |
Family
ID=11770605
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63011171A Expired - Lifetime JPH0775041B2 (en) | 1988-01-21 | 1988-01-21 | Bias magnetic field supply device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0775041B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6766793B2 (en) * | 2002-12-12 | 2004-07-27 | General Atomics | Electromagnetic gun and rotating pulse forming network |
| WO2005071622A1 (en) * | 2004-01-27 | 2005-08-04 | Sankyo Seiki Mfg. Co., Ltd. | Paper leaves identifying sensor and paper leaves identifying device |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6265202A (en) * | 1985-09-18 | 1987-03-24 | Canon Inc | Auxiliary magnetic field impressing device |
-
1988
- 1988-01-21 JP JP63011171A patent/JPH0775041B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01185804A (en) | 1989-07-25 |
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