JP2541918B2 - Magneto-optical recording method - Google Patents
Magneto-optical recording methodInfo
- Publication number
- JP2541918B2 JP2541918B2 JP58027773A JP2777383A JP2541918B2 JP 2541918 B2 JP2541918 B2 JP 2541918B2 JP 58027773 A JP58027773 A JP 58027773A JP 2777383 A JP2777383 A JP 2777383A JP 2541918 B2 JP2541918 B2 JP 2541918B2
- Authority
- JP
- Japan
- Prior art keywords
- magneto
- recording
- recording medium
- laser
- optical recording
- 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
- G11B11/10502—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
- G11B11/10504—Recording
-
- 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
- G11B11/10515—Reproducing
Landscapes
- Recording Or Reproducing By Magnetic Means (AREA)
Description
【発明の詳細な説明】 技術分野 本発明は、磁気記録媒体に光を照射して磁気記録媒体
に情報の記録を行なう光磁気記録方法に関するものであ
り、より詳細には、磁性体に光を照射して公知の熱磁気
効果により、磁性体の磁化の方向を制御して情報の記録
を行なう光磁気記録方法に関するものである。TECHNICAL FIELD The present invention relates to a magneto-optical recording method for recording information on a magnetic recording medium by irradiating the magnetic recording medium with light. More specifically, the present invention relates to a magneto-optical recording method. The present invention relates to a magneto-optical recording method in which information is recorded by controlling the direction of magnetization of a magnetic body by irradiation with a known thermomagnetic effect.
従来技術 ビデオ信号を周波数変調して感光体で構成されている
ビデオデイスク原盤にレーザで記録する場合、先ず、第
１図ａに示す様な周波数変調されたカラー映像信号と、
第１図ｂに示す様な周波数変調された音声信号とを加算
して、第１図ｃに示す様な周波数変調されたビデオ信号
を形成する。このビデオ信号ｃを、第１図ｄに示す様な
リミツタ波形ｄに変換し、このリミツタ波形ｄと連動し
てデイスク上にレーザを点滅しながら照射して、第１図
ｅに示す様な一連の記録ピツトをデイスク上に形成す
る。即ち、ビデオ信号を記録する場合、周波数の変化で
映像信号を記録し、デユーテイ比の変化で音声信号を記
録する。そしてデイスク上では、第１図ｅに示す如くデ
ユーテイ比の変化は記録ピツトの列方向の長さ変化で表
わされる。一方、再生を行なう場合には、デイスクにレ
ーザを照射してデイスクの記録ピツトｅを読み出し加算
波形ｃを得る。2. Description of the Related Art When a video signal is frequency-modulated and recorded on a video disc master made of a photoconductor by a laser, first, a frequency-modulated color image signal as shown in FIG.
A frequency-modulated audio signal as shown in FIG. 1b is added to form a frequency-modulated video signal as shown in FIG. 1c. This video signal c is converted into a limiter waveform d as shown in FIG. 1d, and in conjunction with this limiter waveform d, a disk is irradiated while blinking a laser, and a series as shown in FIG. The recording pit of is formed on the disk. That is, when recording a video signal, a video signal is recorded by changing the frequency and an audio signal is recorded by changing the duty ratio. Then, on the disk, the change in the duty ratio is represented by the change in the length of the recording pit in the column direction as shown in FIG. On the other hand, when reproducing is performed, the disk is irradiated with a laser to read the recording pit e of the disk and obtain the added waveform c.
然しながら、磁性体から構成されているデイスクに光
磁気記録法で信号を記録する場合には、第１図ｅで示さ
れる様なデユーテイ比の変化を記録ピツトの列方向の長
さ変化で表わす様な記録ビツトのパターンをデイスクに
レーザを照射して形成しようとすると、微小な記録ピツ
トに対し長さ変化を持たせる様にレーザを照射したとし
ても、磁性体に存在する磁壁エネルギーの作用を受けて
微小な記録ビツトは実質的に円形となり、デユーテイ比
の変化を記録ビツトの列方向の長さ変化で表わし難いと
いう問題がある。又、記録ビツトの大きさを大きくして
長さ変化を持たせ様とすると、デイスクに情報を高密度
に記録することができないという欠点が生じる。However, when a signal is recorded on a disk made of a magnetic material by the magneto-optical recording method, a change in the duty ratio as shown in FIG. 1e is represented by a change in the length of the recording pit in the column direction. If an attempt is made to irradiate a disk with a proper recording bit pattern by irradiating it with a laser, even if the laser is irradiated so as to change the length of a minute recording pit, it will be affected by the domain wall energy existing in the magnetic substance. The minute recording bits are substantially circular, and there is a problem in that it is difficult to represent changes in the duty ratio by changes in the length of the recording bits in the column direction. Further, if the size of the recording bit is increased so as to have a change in length, there is a drawback that information cannot be recorded at high density on the disk.
目的 本発明は、以上の点に鑑みなされたものであり、周波
数変調された信号を微小な記録ビツトで高密度に記録・
再生することが可能な光磁気記録方法を提供することを
目的とする。The present invention has been made in view of the above points, and records a frequency-modulated signal at a high density with a minute recording bit.
An object is to provide a magneto-optical recording method capable of reproducing.
構成 以下、本発明の具体的実施の態様に付いて添付の図面
を参考に説明する。本発明は、磁化の方向が一方向に配
向されている磁性薄膜が基板上に形成されている磁気記
録媒体にレーザ等から光を照射し、この照射による磁気
記録媒体の照射域の温度上昇による公知の熱磁気効果の
ため照射域の磁性体内部の磁化を可動状態にして、それ
と同時に磁性体内部の反磁界もしくは磁化の反転を助け
るに意図的に加えられた磁界等の外部磁界により、磁化
の配向を制御して、磁気記録媒体に情報を記憶する光磁
気記録方法において、情報信号に応じて磁気記録媒体に
光照射し記録するビツトの面積を変化させて磁気記録媒
体に情報を記録するものである。例えば、情報信号とし
て第１図ｂに示される様な周波数変調された音声信号を
デユーテイ比の変化で磁気記録媒体に光磁気記録方法を
用いて記録する場合、微小な記録ビツトは磁壁エネルギ
ーにより円形状となることに鑑みて、第２図ｆに示す如
く、周波数変調された信号のデユーテイ比の変化を照射
する円形ビームスポツト（記録ビツト）の大きさ、即ち
面積の変化で表わして、一定の周波数で磁気記録媒体に
レーザを照射する。この様な円形のレーザ照射域は、磁
化の方向が照射域周辺の磁化の方向と逆方向に配向され
て、記録ビツトが形成される。Configuration Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings. The present invention irradiates a magnetic recording medium having a magnetic thin film whose magnetization direction is oriented in one direction on a substrate with light from a laser or the like, and increases the temperature of an irradiation area of the magnetic recording medium by this irradiation. Due to the well-known thermomagnetic effect, the magnetization inside the magnetic substance in the irradiation area is made movable, and at the same time, the external magnetic field such as the demagnetizing field inside the magnetic substance or the magnetic field intentionally added to assist the reversal of the magnetization In the magneto-optical recording method of controlling the orientation of the magnetic recording medium to store information in the magnetic recording medium, the information is recorded on the magnetic recording medium by changing the area of a bit to be recorded by irradiating the magnetic recording medium with light according to an information signal. It is a thing. For example, when a frequency-modulated audio signal as shown in FIG. 1b is recorded as an information signal on a magnetic recording medium by a magneto-optical recording method with a change in duty ratio, a minute recording bit is a circle due to domain wall energy. In view of the shape, as shown in FIG. 2f, the change of the duty ratio of the frequency-modulated signal is represented by the size of the circular beam spot (recording bit), that is, the change of the area, and is constant. Irradiate the magnetic recording medium with a laser at a frequency. In such a circular laser irradiation area, the magnetization direction is oriented in the opposite direction to the magnetization direction around the irradiation area, and a recording bit is formed.
又、第3a図及び第3b図は、夫々、光磁気記録における
照射レーザ・パワーと記録されたスポツト径の関係及び
レーザ・ビーム照射時に与える外部磁界と記録スポツト
の関係を示すグラフ図であるが、レーザ・パワーを制御
しながらビームポツト（記録ビツト）の面積を変化させ
るよりも外部磁界を制御してビームスポツト（記録ビツ
ト）の大きさを制御する方が望ましい。この様な制御を
行なうことにより第２図ｆで示される様な微小な記録ビ
ツトが得られる。Further, FIGS. 3a and 3b are graphs showing the relationship between the irradiation laser power and the recorded spot diameter in magneto-optical recording, and the relationship between the external magnetic field given at the time of laser beam irradiation and the recording spot, respectively. It is desirable to control the size of the beam spot (recording bit) by controlling the external magnetic field rather than changing the area of the beam spot (recording bit) while controlling the laser power. By performing such control, a minute recording bit as shown in FIG. 2f can be obtained.
この記録ビツトのパターンを再生するには、磁気記録
媒体にレーザを照射し、公知の磁気光学効果により偏光
面の回転を検知すれば良い。この様にして再生を行なう
と第２図の記録ビツトのパターンｆに対して第２図で示
される様な再生変調波ｇが得られる。再生のレーザ照射
において、記録ビツトの列方向の長さ（直径）に対して
照射したビームのスポット径が小さなときは、ビツトの
直径に対して再生波形は変調を受けるが、一般的に記録
ビツトの径とレーザ・ビームの径が同程度の大きさある
ため、記録ビツトの面積に応じて再生波形は変調され
る。In order to reproduce the pattern of the recording bit, the magnetic recording medium may be irradiated with a laser and the rotation of the polarization plane may be detected by the known magneto-optical effect. When reproduction is carried out in this manner, a reproduction modulated wave g as shown in FIG. 2 is obtained for the recording bit pattern f in FIG. In the laser irradiation for reproduction, when the spot diameter of the irradiated beam is small with respect to the length (diameter) of the recording bit in the column direction, the reproduction waveform is modulated with respect to the diameter of the bit, but generally the recording bit is And the diameter of the laser beam are almost the same, the reproduced waveform is modulated according to the area of the recording bit.
次に、第４図を参考に本発明に基づき外部磁界を変化
させることによつてビームスポツト（記録ビツト）の径
を制御して光磁気記録の書込を行なう装置について説明
する。周波数変調波発生源10からレーザ発振用電源８と
外部磁界制御用装置９に周波数変調波が伝達され、半導
体レーザ１はレーザ発振用電源８から伝達される信号の
周波数に応じてレーザが点滅され、外部磁界用コイル６
は外部磁界制御装置から周波数変調波に応じた電流変化
に従つて磁界を発生する。半導体レーザ１から出たレー
ザはカツプリングレンズ２で平行光にされ、偏光ビーム
スプリツタ３を通過し、４分の１波長板４を通過し、対
物レンズ５に集束光にされ、更に外部磁界用コイル６に
よりビームスポツト（記録ビツト）の大きさが制御され
て、磁気記録媒体７に照射される。Next, with reference to FIG. 4, an apparatus for writing magneto-optical recording by controlling the diameter of the beam spot (recording bit) by changing the external magnetic field according to the present invention will be described. The frequency-modulated wave is transmitted from the frequency-modulated wave generation source 10 to the laser oscillation power supply 8 and the external magnetic field control device 9, and the semiconductor laser 1 blinks in accordance with the frequency of the signal transmitted from the laser oscillation power supply 8. , External magnetic field coil 6
Generates a magnetic field from an external magnetic field control device according to a change in current according to a frequency modulated wave. The laser emitted from the semiconductor laser 1 is collimated by the coupling lens 2, passes through the polarization beam splitter 3, passes through the quarter-wave plate 4 and is converged by the objective lens 5, and further the external magnetic field is applied. The size of the beam spot (recording bit) is controlled by the use coil 6 and the magnetic recording medium 7 is irradiated with the beam spot.
効果 以上、詳述した如く、本発明光磁気記録方法に拠れ
ば、周波数変調された信号を円形の微小な記録ビツトに
形成し、デユーテイ比の変化を円形の面積変化に対応さ
せて記録するため、周波数変調された信号を高密度に記
憶・再生することが可能となる。Effect As described above in detail, according to the magneto-optical recording method of the present invention, the frequency-modulated signal is formed into a circular minute recording bit, and the change in the duty ratio is recorded in correspondence with the circular area change. It becomes possible to store and reproduce a frequency-modulated signal with high density.
第１図は一連のビデオ信号波形とデイスクに形成された
記録ビツトを示したグラフ図、第２図は磁気記録媒体に
形成された記録ビツトｆとこの記録ビツトに応じて再生
された再生波形ｇを示すグラフ図、第3a図はレーザ・パ
ワーと記録されスポツト径の関係を示すグラフ図、第3b
図は外部磁界と記録されたスポツト径の関係を示すグラ
フ図、第４図は外部磁界によりビームスポツト径を制御
して光磁気書込を行なう装置の構成図である。 （符号の説明） 1:半導体レーザ、5:対物レンズ 6:外部磁界用コイル、7:磁気記録媒体 8:レーザ発振用電源、9:外部磁界制御用装置 10:周波数変調波発生源FIG. 1 is a graph showing a series of video signal waveforms and recording bits formed on a disk, and FIG. 2 is a recording bit f formed on a magnetic recording medium and a reproduction waveform g reproduced according to the recording bits. Figure 3a is a graph showing the relationship between laser power and spot diameter recorded.
FIG. 4 is a graph showing the relationship between the external magnetic field and the recorded spot diameter. FIG. 4 is a block diagram of an apparatus for controlling the beam spot diameter by the external magnetic field to perform magneto-optical writing. (Explanation of symbols) 1: Semiconductor laser, 5: Objective lens 6: Coil for external magnetic field, 7: Magnetic recording medium 8: Power supply for laser oscillation, 9: Device for controlling external magnetic field 10: Source of frequency modulated wave
Claims (1)
る前記磁気記録媒体の照射域の温度上昇と同時に前記照
射域に加えられた外部磁界により、前記磁気記録媒体の
磁化の方向を制御して、前記記録媒体に情報を記録する
光磁気記録方法において、磁化反転させる部分の面積
を、情報信号に対応した略円形形状の面積として変化さ
せることにより、前記磁気記録媒体に情報を記録するこ
とを特徴とする光磁気記録方法。1. A magnetic recording medium is irradiated with light, and the direction of magnetization of the magnetic recording medium is controlled by an external magnetic field applied to the irradiated region at the same time as the temperature of the irradiated region of the magnetic recording medium rises due to the irradiation. Then, in the magneto-optical recording method for recording information on the recording medium, the information is recorded on the magnetic recording medium by changing the area of the portion where the magnetization is inverted to a substantially circular area corresponding to the information signal. A magneto-optical recording method characterized by the above.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58027773A JP2541918B2 (en) | 1983-02-23 | 1983-02-23 | Magneto-optical recording method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58027773A JP2541918B2 (en) | 1983-02-23 | 1983-02-23 | Magneto-optical recording method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59154604A JPS59154604A (en) | 1984-09-03 |
| JP2541918B2 true JP2541918B2 (en) | 1996-10-09 |
Family
ID=12230289
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58027773A Expired - Lifetime JP2541918B2 (en) | 1983-02-23 | 1983-02-23 | Magneto-optical recording method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2541918B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2800003B2 (en) * | 1987-03-25 | 1998-09-21 | 株式会社リコー | Magneto-optical recording method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS51141608A (en) * | 1975-06-02 | 1976-12-06 | Mitsubishi Electric Corp | Information and reproduction system |
-
1983
- 1983-02-23 JP JP58027773A patent/JP2541918B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59154604A (en) | 1984-09-03 |
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