JPH0123845B2 - - Google Patents
Info
- Publication number
- JPH0123845B2 JPH0123845B2 JP56073388A JP7338881A JPH0123845B2 JP H0123845 B2 JPH0123845 B2 JP H0123845B2 JP 56073388 A JP56073388 A JP 56073388A JP 7338881 A JP7338881 A JP 7338881A JP H0123845 B2 JPH0123845 B2 JP H0123845B2
- Authority
- JP
- Japan
- Prior art keywords
- light beam
- recording
- magnetic
- magnetic recording
- recording 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.)
- Expired
Links
- 238000000034 method Methods 0.000 claims description 10
- 230000005415 magnetization Effects 0.000 description 4
- 239000000758 substrate Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000000265 homogenisation Methods 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 230000005381 magnetic domain Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
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
- G11B11/10502—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 characterised by the transducing operation to be executed
- G11B11/10528—Shaping of magnetic domains, e.g. form, dimensions
Landscapes
- Recording Or Reproducing By Magnetic Means (AREA)
- Optical Recording Or Reproduction (AREA)
Description
【発明の詳細な説明】
本発明は磁気記録再生方法、特に光ビームの照
射による光磁気記録方式に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic recording and reproducing method, particularly to a magneto-optical recording method using light beam irradiation.
磁気記録の高密度化は、記録媒体の進歩、即ち
記録媒体の膜の均質化、高保磁力化、磁区の微細
化等により著しく向上し、数オングストロームの
反転磁化を記録することも可能になつた。しか
し、磁気ヘツドによる書込み、読み出しを、この
ような高密度化された記録媒体に対応させること
は、ヘツド媒体の幾何学的スペーシングの関係上
困難である。 The density of magnetic recording has improved significantly due to advances in recording media, such as homogenization of recording media films, higher coercive force, and finer magnetic domains, and it has become possible to record reversal magnetization of several angstroms. . However, it is difficult to adapt writing and reading by a magnetic head to such a high-density recording medium due to the geometrical spacing of the head medium.
これを回避するものとして光ビームによつて磁
気媒体に書き込みかつ読み出しを行なう光磁気記
録方式が提案されている。この方式では、第２図
に示すように、光ビーム１を収来させ、光ビーム
１の収束した部分を磁気媒体２に照射する一方、
コイル３によつて光ビーム１に磁界を与える。磁
気媒体２はあらかじめ例えばＮ極に磁化されてい
るとすると、コイル３に反転電流を与えることに
より、光ビームの照射部分のみがＳ極に反転す
る。そこで、光ビーム１又は磁気媒体２のいずれ
か一方を移動させることにより、第１図に示すよ
うに、磁気媒体２上にＳ極に反転したスポツト１
０が形成されてゆく。しかしながら、光ビームの
収束には光の波長によつて先天的に定められるビ
ーム径の収束限界がある。即ち、光の波長入、開
口数NAとすると、収束されたビームの径ｄは、
ｄ＞２／π 入／NA
となることが知られている。このため、光磁気記
録は、第１図に示すように、Ｓ極に反転したスポ
ツト１０が、粒々に並んだ状態で残されることに
なり、隣接するトラツクの間隔ｐもこのスポツト
に対し十分な間隔をとるのが普通である。このよ
うな制約により、１つ１つの記録の大きさは、媒
体自体の密度限界に関係なく、光のスポツトサイ
ズでまず与えられてしまい、又隣接トラツクとの
間に無駄な空白区域も残す為にその面の記録密度
をあまり上げることはできない。 To avoid this problem, a magneto-optical recording method has been proposed in which writing and reading are performed on a magnetic medium using a light beam. In this method, as shown in FIG. 2, the light beam 1 is converged and the converged portion of the light beam 1 is irradiated onto the magnetic medium 2.
A magnetic field is applied to the light beam 1 by means of a coil 3 . Assuming that the magnetic medium 2 is previously magnetized to the north pole, for example, by applying a reversal current to the coil 3, only the portion irradiated with the light beam is reversed to the south pole. Therefore, by moving either the light beam 1 or the magnetic medium 2, as shown in FIG.
0 is being formed. However, when converging a light beam, there is a convergence limit on the beam diameter that is determined a priori by the wavelength of the light. That is, it is known that the diameter d of a converged beam is d>2/π input/NA, where the wavelength of light is input and the numerical aperture is NA. For this reason, in magneto-optical recording, as shown in Fig. 1, spots 10 with reversed S poles are left in a lined-up state, and the spacing p between adjacent tracks is also sufficient for these spots. It is normal to keep an interval. Due to these constraints, the size of each recording is first given by the spot size of the light, regardless of the density limit of the medium itself, and wasteful blank areas are also left between adjacent tracks. Therefore, it is not possible to increase the recording density on that surface very much.
本発明はこの改良を目的としたもので、光ビー
ムそのもののスポツトサイズを変えることなく、
ビツト間隔を詰めていくことによりビーム径より
狭いビツチで記録し、磁気記録媒体の単位面積あ
たりの記録密度を上げた光磁気記録の再生方法、
特に再生の際、記録されている後続ビツトの読み
取りを出来る限り阻止する光磁気記録再生方法を
提供するものである。 The present invention aims to improve this, without changing the spot size of the light beam itself.
A method for reproducing magneto-optical recording in which the recording density per unit area of the magnetic recording medium is increased by recording with bits narrower than the beam diameter by narrowing the bit interval;
In particular, the present invention provides a magneto-optical recording and reproducing method that prevents reading of subsequent recorded bits as much as possible during reproduction.
この目的を達成するために、本発明では、光ビ
ームの集束部分を磁気記録媒体に照射すると共
に、前記磁気記録媒体に反転磁界を与え、光ビー
ム又は磁気記録媒体を移動させて、各光ビームの
照射部分の後縁に残留記録を残すように記録した
前記磁気記録媒体に、再生用の光ビームの集束部
分を照射して読み取り、該読み取り信号中の後続
ビツトの成立をトランスバーサルフイルタを介し
て遅延加算することを特徴とする光磁気記録再生
方法が提供される。 To achieve this objective, the present invention irradiates a magnetic recording medium with a focused portion of a light beam, applies a reversal magnetic field to the magnetic recording medium, moves the light beam or the magnetic recording medium, and each light beam A focused portion of the light beam for reproduction is irradiated onto the magnetic recording medium recorded so as to leave a residual record at the trailing edge of the irradiated portion, and the formation of subsequent bits in the read signal is detected through a transversal filter. A magneto-optical recording and reproducing method is provided, which is characterized in that delay addition is performed.
このように本発明では、読み取り信号中の後続
ビツトの成分をトランスバーサルフイルタを介し
て遅延加算しているので、読み取つた信号中の後
続ビツトの成分が大幅に弱められ、必要な信号の
みを取り出すことができる。 In this way, in the present invention, the components of subsequent bits in the read signal are delayed and added via the transversal filter, so the components of the subsequent bits in the read signal are significantly weakened, making it possible to extract only the necessary signal. be able to.
以下、図面を参照し本発明について詳細に説明
する。 Hereinafter, the present invention will be explained in detail with reference to the drawings.
第２図及び第３図において、光ビーム１をレン
ズ４によつて収束断面が円形又は楕円形になるよ
う収束し、その収束部分を基板５の磁気媒体２に
照射する。基板５上の磁気媒体２はあらかじめＮ
極にもＳ極にも反転されていない。光ビーム１の
収束部分の附近に、光ビーム１に磁界を与えるコ
イル３とを配し、このコイル３に記録電流を流し
ビツト列に応じた反転電流を与えると、交照射部
のみ温度が上昇して抗磁力が減少し、コイル磁界
の方向に容易に磁化反転するが、周囲は室温の
まゝで保磁力が高く磁化方向は維持される。即
ち、コイル３による磁界がＮ極のときは、その光
ビーム１の照射部分がＮ極に反転し、逆に、コイ
ル３による磁界がＳ極のときは、その光ビーム１
の照射部分はＳ極に反転し、その磁化方向が維持
される。 In FIGS. 2 and 3, a light beam 1 is converged by a lens 4 so that its convergence cross section becomes circular or elliptical, and the converged portion is irradiated onto a magnetic medium 2 on a substrate 5. The magnetic medium 2 on the substrate 5 is preliminarily
Neither the pole nor the south pole is reversed. A coil 3 that applies a magnetic field to the light beam 1 is arranged near the convergence part of the light beam 1, and when a recording current is passed through this coil 3 and a reversal current corresponding to the bit string is applied, the temperature only rises in the alternating irradiation part. As a result, the coercive force decreases and the magnetization is easily reversed in the direction of the coil magnetic field, but the coercive force is high and the magnetization direction is maintained while the surroundings remain at room temperature. That is, when the magnetic field produced by the coil 3 is north pole, the irradiated portion of the light beam 1 is reversed to the north pole, and conversely, when the magnetic field produced by the coil 3 is south pole, the light beam 1
The irradiated part is reversed to the south pole, and its magnetization direction is maintained.
このとき、光ビーム１又は基板５（磁気媒体
２）の送り速度を遅くすると、磁気媒体２上でＮ
極又はＳ極に反転した光ビームスポツトは順次重
なり、各光ビームスポツトの後縁部の加熱形状が
三日月形に順次残り、第３図に示すような記録が
残される。即ち、第３図において、符号７で示す
領域がレンズ４で収束された光ビームの照射領域
であり、符号８1，８2，８3，８4で示す領域が残
留記録の領域である。また、矢印Ｑは基板（磁気
媒体）の送り方向である。このような各三日月形
の記録領域８1，８2，８3，８4は光ビームの照射
領域７よりも面積が小さく、それだけ記録密度が
上げられる。 At this time, if the feeding speed of the light beam 1 or the substrate 5 (magnetic medium 2) is slowed down, N
The light beam spots reversed to poles or south poles are successively overlapped, and the heated shape of the trailing edge of each light beam spot remains in a crescent shape, leaving a record as shown in FIG. That is, in FIG. 3, the area indicated by reference numeral 7 is the irradiation area of the light beam converged by the lens 4, and the areas indicated by reference numerals 8 1 , 8 2 , 8 3 , and 8 4 are the areas of residual recording. Further, arrow Q is the feeding direction of the substrate (magnetic medium). Each of these crescent-shaped recording areas 8 1 , 8 2 , 8 3 , 8 4 has a smaller area than the light beam irradiation area 7, and the recording density can be increased accordingly.
光ビームの収束断面が円形の場合は、磁気媒体
上に第４図に示すような三日月形の残留記録８1，
８2，８3，８4………が残される。なお、斜線の
領域は磁化されない部分である。このような記録
の読み出しを光ビームの照射で行なう場合、その
ビーム内には後続ビツトの記録が含まれて弁別で
きないという難点がある。例えば、第４図におい
て、破線９で示す領域が記録読み出しのための光
ビーム照射領域であるとすると、この領域内には
残留記録８2，８3，８4，８5が含まれてしまう。
しかし、この難点は、第５図に示すように、読み
出し信号中の後続ビツトの成分をトランスバーサ
ルフイルタのように遅延加算することにより幾分
改良することができる。なお、第５図において、
符号２は情報が記録された磁気媒体、符号１′は
読み出し用の光ビーム、符号１１は光検出器、Ｄ
は遅延要素、A1，A2，A3………は乗算要素であ
る。また、記録読み出し用の光ビーム照射面積
は、通常は、第４図の破線９で示すように、記録
の際の光ビーム照射面積よりも小さくする。 When the convergence cross section of the light beam is circular, a crescent-shaped residual record 8 1 , as shown in Figure 4, is created on the magnetic medium.
8 2 , 8 3 , 8 4 ...... are left. Note that the shaded area is a portion that is not magnetized. When such a record is read out by irradiating a light beam, there is a problem in that the beam contains records of subsequent bits and cannot be distinguished. For example, in FIG. 4, if the area indicated by the broken line 9 is the light beam irradiation area for reading the records, this area will include residual records 8 2 , 8 3 , 8 4 , and 8 5 . .
However, this difficulty can be somewhat improved by delay-adding the components of subsequent bits in the read signal like a transversal filter, as shown in FIG. In addition, in Fig. 5,
Reference numeral 2 is a magnetic medium on which information is recorded, reference numeral 1' is a light beam for reading, reference numeral 11 is a photodetector, D
is a delay element, and A 1 , A 2 , A 3 . . . are multiplication elements. Further, the light beam irradiation area for recording and reading is usually smaller than the light beam irradiation area for recording, as shown by the broken line 9 in FIG.
又、隣接トラツク成分との近接干渉について
は、VTRの記録で知られるアジマスが逆である
ことによる干渉の低減と同様の形状関係が成りた
つており、たとえ読出し光ビームが隣接トラツク
の縁にまたがつてもそこは極めて細かいN.Sの混
合領域で信号としての影響は少ない。この為、ト
ラツクピツチは近づけることが可能となる。 In addition, regarding close interference with adjacent track components, a shape relationship similar to the reduction in interference due to reverse azimuth, which is known in VTR recording, is established, and even if the readout light beam crosses the edge of an adjacent track, However, this area is a very fine NS mixture area and has little effect on the signal. Therefore, the track pitch can be brought closer.
なお、半導体レーザは構造的に発光ビーム（断
面）が偏平となるものが多く、その光ビームは送
り方向と直交する方向にのびる如く偏平に絞るこ
とにより、第６図に示すような残留記録とするの
も、記録の高密度化を更に達成するために有利な
場合がある。なお、第６図において、符号１２の
領域は長ビツトの領域である。 Note that many semiconductor lasers have a flat emitted beam (cross section) due to their structure, and by focusing the light beam flat so that it extends in a direction perpendicular to the feeding direction, residual recording as shown in Figure 6 can be achieved. It may also be advantageous to further achieve higher recording density. In FIG. 6, the area 12 is a long bit area.
第１図は従来の光磁気記録方式による残留記録
を示す図、第２図は光ビームによつて磁気記録を
している状態を示す図、第３図は本発明による光
磁気記録の状態を示す図、第４図は本発明の磁気
記録方式による残留記録を示す図、第５図は本発
明による記録の読み出しを行なう状態を示す図、
第６図は偏平な光ビームによつて磁気記録された
状態を示す図である。
１，１′……光ビーム、２……磁気記録媒体、
３……コイル、４……レンズ、７……光ビームの
照射領域、８1，８2，８3……残留記録。
Fig. 1 shows residual recording using the conventional magneto-optical recording method, Fig. 2 shows the state of magnetic recording using a light beam, and Fig. 3 shows the state of magneto-optical recording according to the present invention. FIG. 4 is a diagram showing residual recording by the magnetic recording method of the present invention, and FIG. 5 is a diagram showing a state in which recording is read according to the present invention.
FIG. 6 is a diagram showing a state in which magnetic recording is performed using a flat light beam. 1,1'...Light beam, 2...Magnetic recording medium,
3...Coil, 4...Lens, 7...Light beam irradiation area, 81 , 82 , 83 ...Residual recording.
Claims (1)
射すると共に、前記磁気記録媒体に反転磁界を与
え、光ビーム又は磁気記録媒体を移動させて、各
光ビームの照射部分の後縁に残留記録を残すよう
に記録した前記磁気記録媒体２に、再生用の光ビ
ーム１′の集束部分を照射して読み取り、該読み
取り信号中の後続ビツトの成分をトランスバーサ
ルフイルタを介して遅延加算することを特徴とす
る光磁気記録再生方法。1. Irradiate the focused portion of the light beam 1 onto the magnetic recording medium 2, apply a reversal magnetic field to the magnetic recording medium, move the light beam or the magnetic recording medium, and record residual information at the trailing edge of the irradiated portion of each light beam. The magnetic recording medium 2, which has been recorded so as to leave a . Characteristic magneto-optical recording and reproducing method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7338881A JPS57189302A (en) | 1981-05-18 | 1981-05-18 | Optical magnetic recording system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7338881A JPS57189302A (en) | 1981-05-18 | 1981-05-18 | Optical magnetic recording system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57189302A JPS57189302A (en) | 1982-11-20 |
| JPH0123845B2 true JPH0123845B2 (en) | 1989-05-09 |
Family
ID=13516755
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7338881A Granted JPS57189302A (en) | 1981-05-18 | 1981-05-18 | Optical magnetic recording system |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57189302A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59215008A (en) * | 1983-05-20 | 1984-12-04 | Canon Inc | Optical magnetic disc device |
| JPS61214228A (en) * | 1985-03-20 | 1986-09-24 | Hitachi Ltd | Information recording method |
| JP2800003B2 (en) * | 1987-03-25 | 1998-09-21 | 株式会社リコー | Magneto-optical recording method |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57186248A (en) * | 1981-05-09 | 1982-11-16 | Ricoh Co Ltd | Vertically thermomagnetic recording and reproducing system |
-
1981
- 1981-05-18 JP JP7338881A patent/JPS57189302A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57186248A (en) * | 1981-05-09 | 1982-11-16 | Ricoh Co Ltd | Vertically thermomagnetic recording and reproducing system |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57189302A (en) | 1982-11-20 |
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