JP2519197B2 - Thermomagnetic recording device - Google Patents
Thermomagnetic recording deviceInfo
- Publication number
- JP2519197B2 JP2519197B2 JP57165880A JP16588082A JP2519197B2 JP 2519197 B2 JP2519197 B2 JP 2519197B2 JP 57165880 A JP57165880 A JP 57165880A JP 16588082 A JP16588082 A JP 16588082A JP 2519197 B2 JP2519197 B2 JP 2519197B2
- Authority
- JP
- Japan
- Prior art keywords
- recording
- magnetic field
- thin film
- recording medium
- magnetic thin
- 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
- G11B11/10517—Overwriting or erasing
-
- 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
Landscapes
- Recording Or Reproducing By Magnetic Means (AREA)
Description
【発明の詳細な説明】 〈技術分野〉 本発明はレーザ光の照射熱により情報の記録と消去を
行なう熱磁気記録装置に関する。Description: TECHNICAL FIELD The present invention relates to a thermomagnetic recording apparatus for recording and erasing information by the irradiation heat of laser light.
〈従来技術〉 近年、高密度，大容量，高速アクセス等の要求を満足
し得る光メモリ装置の研究開発が活発に推進されてい
る。中でも半導体レーザを用いて情報の記録・再生・消
去が可能な光磁気ディスクメモリは画像，文字等のファ
イルメモリやビデオディスクメモリへの応用が考えられ
る為に特に注目されている。<Prior Art> In recent years, research and development of an optical memory device capable of satisfying requirements such as high density, large capacity, and high speed access have been actively promoted. Among them, a magneto-optical disk memory capable of recording / reproducing / erasing information by using a semiconductor laser is particularly attracting attention because it can be applied to a file memory for images and characters and a video disk memory.
光磁気ディスクメモリへの記録はキューリ点記録、
補償点記録、保持力の温度変化を利用する記録に分
類される。これらはいずれの方式も適当な外部磁場のも
とでレーザ光により局所的に記録媒体（磁性体薄膜）の
温度を上げその部分の磁化を上記外部磁場の向きに変化
させる事で記録する所謂熱磁気記録である。Curie point recording for recording on magneto-optical disk memory,
It is classified into the compensation point record and the record using the temperature change of the holding force. In any of these methods, so-called thermal recording is performed by locally raising the temperature of the recording medium (magnetic thin film) by a laser beam under an appropriate external magnetic field and changing the magnetization of that portion in the direction of the external magnetic field. It is magnetic recording.
次にこの熱磁気記録の公知な方式について概略的に説
明する。第１図は従来の熱磁気記録の方式の一例を表わ
す。１はガラス等の透明基板、２は記録磁性体薄膜、３
は保護板である。４はレーザ光、５はレーザ光を集光す
る集光レンズで、６は上記記録磁性体薄膜に対して磁場
を供給するコイルである。この第１図に示した方式はコ
イルに流す電流の方向或いは電流の大きさを変えれば容
易に必要とする磁場を得ることができるので、機構上は
簡単になるが、上記記録磁性体薄膜２へ磁場を供給する
為には上記透明基板１ごしに磁場を供給しなければなら
ず、その為できる限り上記コイル６を上記透明基板１に
近づけても上記コイル６の上記記録磁性体薄膜２への供
給磁場を充分なものにすることが困難であった。しかる
に通常上記記録磁性体薄膜には記録時あるいは消去時に
上記記録磁性体薄膜上で100Oe（エルステッド）以上の
非常に大きな磁場を必要としたので上記コイル６に流す
電流を多くするか、上記コイル６を大きくするといった
対応が必要であった。しかしこのいずれの対応も装置が
大型化し実用的ではなかった。Next, a known method of this thermomagnetic recording will be schematically described. FIG. 1 shows an example of a conventional thermomagnetic recording system. 1 is a transparent substrate such as glass, 2 is a recording magnetic thin film, 3
Is a protective plate. Reference numeral 4 is a laser beam, 5 is a condenser lens for condensing the laser beam, and 6 is a coil for supplying a magnetic field to the recording magnetic thin film. In the system shown in FIG. 1, the required magnetic field can be easily obtained by changing the direction or magnitude of the current flowing through the coil, so that the mechanism is simple, but the recording magnetic thin film 2 described above is used. In order to supply a magnetic field to the transparent substrate 1, a magnetic field must be supplied. Therefore, even if the coil 6 is brought close to the transparent substrate 1 as much as possible, the recording magnetic thin film 2 of the coil 6 is provided. It was difficult to supply a sufficient magnetic field to the. However, since a very large magnetic field of 100 Oe (Oersted) or more is required on the recording magnetic thin film at the time of recording or erasing in the recording magnetic thin film, it is necessary to increase the current flowing through the coil 6 or It was necessary to take measures such as increasing. However, neither of these measures was practical because the device was large.
一方第２図は従来の熱磁気記録の方式の他の例を表わ
す。第１図の方式とは異なり、コイル６の代わりに記録
磁性体薄膜２を挾んで上記集光レンズ５と反対側を永久
磁石７が配置され、該永久磁石７により上記記録磁性体
薄膜２に磁場が供給される。この方式によれば永久磁石
は比較的小型のものでも強い磁場を得ることができるの
で装置を大型化する心配がない。但し永久磁石７の磁場
の大きさについては充分に注意しなければならない。On the other hand, FIG. 2 shows another example of the conventional thermomagnetic recording system. Unlike the system shown in FIG. 1, instead of the coil 6, a recording magnet thin film 2 is sandwiched and a permanent magnet 7 is arranged on the side opposite to the condensing lens 5, and the recording magnet thin film 2 is formed by the permanent magnet 7. A magnetic field is supplied. According to this method, even if the permanent magnet is relatively small, a strong magnetic field can be obtained, so there is no need to worry about increasing the size of the device. However, attention must be paid to the magnitude of the magnetic field of the permanent magnet 7.
〈本発明が解決しようとする問題点〉 本発明者等は永久磁石７の磁場の記録磁性体薄膜２に
対する悪影響について調べた。第３図は記録磁性体薄膜
として有用なGdTbFe非晶質磁性体薄膜の磁気ヒステリシ
ス特性を示す。同図の如くGdTbFe非晶質磁性体薄膜の保
磁力Hcは3.8KOeである。このGdTbFe非晶質磁性体薄膜に
4kOeの消去磁場を与えて第４図（ａ）に示す様に一様に
薄膜の磁化をそろえた後、同図（ｂ）に示す様に磁化と
逆向きの外部磁場Heを印加しその状態を保持した。この
時のGdTbFe非晶質磁性体薄膜の残留磁化の量の時間的変
化を第５図に示す。同図の如く残留磁化量が安定してい
たのは外部磁場Heが1kOeの時でそれより大きな2.0kOe,2
4kOeの場合では時間の経過とともに残留磁化量は減少し
た。<Problems to be Solved by the Present Invention> The present inventors investigated the adverse effect of the magnetic field of the permanent magnet 7 on the recording magnetic thin film 2. FIG. 3 shows the magnetic hysteresis characteristics of a GdTbFe amorphous magnetic thin film useful as a recording magnetic thin film. As shown in the figure, the coercive force Hc of the GdTbFe amorphous magnetic thin film is 3.8 KOe. In this GdTbFe amorphous magnetic thin film
After applying an erasing magnetic field of 4 kOe to uniformly align the magnetization of the thin film as shown in Fig. 4 (a), an external magnetic field He in the opposite direction to the magnetization is applied as shown in Fig. 4 (b). Held. FIG. 5 shows the change over time in the amount of residual magnetization of the GdTbFe amorphous magnetic thin film at this time. As shown in the figure, the residual magnetization was stable when the external magnetic field He was 1 kOe, which was larger than 2.0 kOe, 2.
In the case of 4 kOe, the residual magnetization decreased with the passage of time.
又、同様な例としてGdTbDyFe（Gd0.125 Tb0.1 Dy
0.125 Fe0.75）非晶質磁性体薄膜についても調べた。
該磁性体薄膜の保磁力Hcは6000eであるが、この磁性体
薄膜を用いて記録円盤を作成し特定の信号を記録した後
外部磁場Heを消去方向に300Oe印加しその状態で48〜72h
our放置したところ記録ビット径が小さくなり再生信号
の品質が悪くなった。As a similar example, GdTbDyFe (Gd 0.125 Tb 0.1 Dy
0.125 Fe 0.75 ) amorphous magnetic thin film was also investigated.
The coercive force Hc of the magnetic thin film is 6000e, but after recording a specific disc using this magnetic thin film and recording a specific signal, an external magnetic field He of 300 Oe is applied in the erasing direction and 48-72 h in that state.
When left unattended, the recording bit diameter decreased and the quality of the reproduced signal deteriorated.
又、更に同様な例として磁性体薄膜の組成調整によっ
て保磁力Hcを800OeとしたGdTbDyFe非晶質磁性体薄膜に
ついても調べた。該磁性体薄膜を用いて記録円盤を作成
し特定の信号を記録した後、外部磁場Heを記録方向にて
300Oe印加して放置したところ、記録ビット径が多くな
りこれも再生信号の品質を劣化させた。As a similar example, a GdTbDyFe amorphous magnetic thin film having a coercive force Hc of 800 Oe was also investigated by adjusting the composition of the magnetic thin film. After creating a recording disk using the magnetic thin film and recording a specific signal, an external magnetic field He is applied in the recording direction.
When 300 Oe was applied and left as it was, the recording bit diameter increased, which also deteriorated the quality of the reproduced signal.
以上の例によって示した記録情報の不安定現象は磁性
体薄膜の微小欠陥の部分の磁化が磁性体薄膜の保磁力よ
り小さな逆磁場でも反転しそれを核として磁壁移動によ
り徐々に反転磁化部分が広がることに起因している。The instability phenomenon of the recorded information shown by the above example is such that the magnetization of the minute defects of the magnetic thin film is reversed even in the reverse magnetic field smaller than the coercive force of the magnetic thin film, and the reversal magnetization is gradually caused by the domain wall movement with it as the nucleus. It is due to the spread.
〈目的〉 本発明は上記実験結果を元にしてなされたもので、希
土類−遷移金属系非晶質合金磁性体薄膜を記録媒体とし
た時に、記録情報の不安定現象が生ずることがない補助
磁場の値の適切な条件を備えた熱磁気記録装置を提供す
ることを目的とする。<Purpose> The present invention was made based on the above experimental results, and when a rare earth-transition metal-based amorphous alloy magnetic thin film is used as a recording medium, an auxiliary magnetic field that does not cause an unstable phenomenon of recorded information It is an object of the present invention to provide a thermomagnetic recording device having an appropriate condition of the value of.
〈実施例〉 以下本発明に係る実施例について説明する。<Examples> Examples of the present invention will be described below.
本発明に係る実施例は第２図に示した永久磁石７によ
って記録磁性体薄膜２に磁場を供給する熱磁気記録装置
において、記録磁性体薄膜２をGdTbFe非晶質磁性体薄膜
にて形成し、且つ上記永久磁石７を情報の消去時におい
て上記GdTbFe非晶質磁性体薄膜上に1kOeの強さの磁場を
印加するものとしたものである。上述した如く上記GdTb
Fe非晶質磁性体薄膜の保磁力Hcは3.8kOeである。ここで
本発明者等は上記永久磁石７の上記GdTbFe非晶質磁性体
薄膜上での磁場の値が1.3kOe程度（GdTbFe非晶質磁性体
薄膜の保磁力Hcの約1/3）以下であれば上記永久磁石が
上記GdTbFe非晶質磁性体薄膜に悪影響を及ぼさない即ち
残留磁化が安定である事を確認している。The embodiment according to the present invention is a thermomagnetic recording device for supplying a magnetic field to the recording magnetic thin film 2 by the permanent magnet 7 shown in FIG. 2, in which the recording magnetic thin film 2 is formed of a GdTbFe amorphous magnetic thin film. Moreover, the permanent magnet 7 is adapted to apply a magnetic field having a strength of 1 kOe onto the GdTbFe amorphous magnetic thin film at the time of erasing information. As mentioned above, the above GdTb
The coercive force Hc of the Fe amorphous magnetic thin film is 3.8 kOe. Here, the present inventors found that the value of the magnetic field on the GdTbFe amorphous magnetic thin film of the permanent magnet 7 is about 1.3 kOe (about 1/3 of the coercive force Hc of the GdTbFe amorphous magnetic thin film) or less. If so, it has been confirmed that the permanent magnet does not adversely affect the GdTbFe amorphous magnetic thin film, that is, the residual magnetization is stable.
又、GdTbDyFe非晶質磁性体薄膜を記録磁性体薄膜２と
した場合についても実験したが、この場合も上記永久磁
石７の上記GdTbDyFe非晶質磁性体薄膜上での磁場の値が
上記GdTbDyFe非晶質磁性体薄膜の保持力Hcの約1/3以下
であれば上記永久磁石７が上記GdTbDyFe非晶質磁性体薄
膜に悪影響を及ぼさない事を確認している。Also, an experiment was carried out in the case where the GdTbDyFe amorphous magnetic thin film was used as the recording magnetic thin film 2. In this case as well, the value of the magnetic field of the permanent magnet 7 on the GdTbDyFe amorphous magnetic thin film was the above GdTbDyFe non-magnetic value. It has been confirmed that the permanent magnet 7 does not adversely affect the GdTbDyFe amorphous magnetic thin film if the coercive force Hc of the crystalline magnetic thin film is about 1/3 or less.
以上の説明は消去時における永久磁石の磁場の強さの
適切な値について述べたが、記録時における永久磁石の
磁場の強さは通常消去時より小さくしているので、記録
時においては永久磁石を消去時より弱いものを使用する
か或いは永久磁石を消去時より記録媒体から離間させて
使用する等の方法が考えられる。しかし本発明に係る永
久磁石の磁場の強さの値であれば消去時，記録時に係わ
らず永久磁石は非晶質磁性体薄膜に悪影響を及ぼさない
ので、消去時，記録時共に同じ値の磁場を印加してもよ
い。Although the above description has described an appropriate value of the magnetic field strength of the permanent magnet at the time of erasing, the magnetic field strength of the permanent magnet at the time of recording is smaller than that at the time of normal erasing. It is conceivable to use a weaker magnet than that used for erasing, or to use the permanent magnet at a distance from the recording medium more than when erasing. However, the magnetic field strength of the permanent magnet according to the present invention does not adversely affect the amorphous magnetic thin film during erasing or recording, so that the magnetic field having the same value during erasing and recording is used. May be applied.
〈効果〉 以上のように本発明によれば希土類−遷移金属系非晶
質合金磁性体薄膜の記録媒体に長時間補助磁場を印加し
た状態に放置しておいても、記録磁性体薄膜に記録され
た情報に不安定現象が生ずることがなく安定して保持さ
れるので、記録情報が消滅する等の事故が発生する虞れ
がない熱磁気記録装置を提供することができる。<Effect> As described above, according to the present invention, even if a recording medium of a rare earth-transition metal-based amorphous alloy magnetic thin film is left in a state in which an auxiliary magnetic field is applied for a long time, recording is performed on the recording magnetic thin film. It is possible to provide a thermomagnetic recording device that does not cause an accident such as disappearance of recorded information because the recorded information is stably held without causing an unstable phenomenon.
第１図は従来の熱磁気記録方式の一例を示す説明図、第
２図は従来の熱磁気記録方式の他の例を示す説明図、第
３図はGdTbFe非晶質磁性体薄膜の磁気ヒステリシス特性
を示すグラフ図、第４図はGdTbFe非晶質磁性体薄膜に外
部磁場を印加した説明図、第５図はGdTbFe非晶質磁性体
薄膜の残留磁化の量の時間的変化を示すグラフ図であ
る。 図中、1:透明基板、2:記録磁性体薄膜 3:保護板、4:レーザ光、5:集光レンズ 6:コイル、7:永久磁石FIG. 1 is an explanatory diagram showing an example of a conventional thermomagnetic recording system, FIG. 2 is an explanatory diagram showing another example of a conventional thermomagnetic recording system, and FIG. 3 is a magnetic hysteresis of a GdTbFe amorphous magnetic thin film. Fig. 4 is a graph showing the characteristics, Fig. 4 is an explanatory diagram in which an external magnetic field is applied to the GdTbFe amorphous magnetic thin film, and Fig. 5 is a graph showing the amount of residual magnetization of the GdTbFe amorphous magnetic thin film with time. Is. In the figure, 1: transparent substrate, 2: recording magnetic thin film 3: protective plate, 4: laser light, 5: condenser lens 6: coil, 7: permanent magnet
───────────────────────────────────────────────────── フロントページの続き (72)発明者 片山 博之 大阪市阿倍野区長池町22番22号 シヤ− プ株式会社内 (72)発明者 高橋 明 大阪市阿倍野区長池町22番22号 シヤ− プ株式会社内 (72)発明者 山岡 秀嘉 大阪市阿倍野区長池町22番22号 シヤ− プ株式会社内 (56)参考文献 特開 昭52−153409（ＪＰ，Ａ) 特開 昭54−95250（ＪＰ，Ａ) 特開 昭56−143547（ＪＰ，Ａ) 特開 昭57−24047（ＪＰ，Ａ) 特開 昭57−94948（ＪＰ，Ａ) Ｊａｐａｎｅｓｅ Ｊｏｕｒｎａｌ ｏｆ Ａｐｐｌｉｅｄ Ｐｈｙｓｉｃ ｓ．Ｖｏｌ．18（1979）Ｓｕｐｐｌｅｍ ｅｎｔｅ 18−１ ＰＰ．231−234 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Katayama 22-22 Nagaike-cho, Abeno-ku, Osaka City Group Co., Ltd. (72) Akira Takahashi 22-22 22 Nagaike-cho, Abeno-ku, Osaka City Co., Ltd. (72) Inventor Hideoka Yamaoka 22-22 Nagaike-cho, Abeno-ku, Osaka City, Ltd. (56) References JP-A-52-153409 (JP, A) JP-A-54-95250 (JP, A) ) JP-A-56-143547 (JP, A) JP-A-57-24047 (JP, A) JP-A-57-94948 (JP, A) Japanese Journal of Applied Physics. Vol. 18 (1979) Supplemente 18-1 PP. 231−234
Claims (1)
遷移金属系非晶質合金磁性体薄膜を有する記録媒体と、
前記記録媒体に対して情報の記録／消去を行うためのレ
ーザ光を集光する対物レンズと、前記記録媒体を介して
前記対物レンズの反対側に配され、前記記録媒体に対し
て磁場印加状態に放置される永久磁石から成る補助磁場
印加手段とを備えた熱磁気記録装置において、 前記補助磁場印加手段は、前記記録媒体上における磁場
の強さが前記記録媒体の室温における保持力の1/3以下
となるように成すことによって記録情報品質の経時変化
を抑制し、かつ、消去時と記録時に共に同じ値の磁場を
極性を反転して印加することを特徴とする熱磁気記録装
置。1. A rare earth element having an easy axis of magnetization perpendicular to the film surface.
A recording medium having a transition metal-based amorphous alloy magnetic thin film,
An objective lens that collects laser light for recording / erasing information on the recording medium, and an objective lens that is arranged on the opposite side of the objective lens through the recording medium, and a magnetic field is applied to the recording medium. In the thermomagnetic recording device provided with an auxiliary magnetic field applying unit made of a permanent magnet that is left to stand, the auxiliary magnetic field applying unit is such that the strength of the magnetic field on the recording medium is 1 / of the coercive force of the recording medium at room temperature. A thermomagnetic recording apparatus characterized in that the change in recorded information quality with time is suppressed by setting the number to be 3 or less, and that a magnetic field of the same value is applied with the polarity reversed during both erasing and recording.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57165880A JP2519197B2 (en) | 1982-09-21 | 1982-09-21 | Thermomagnetic recording device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57165880A JP2519197B2 (en) | 1982-09-21 | 1982-09-21 | Thermomagnetic recording device |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4081222A Division JP2889427B2 (en) | 1992-04-03 | 1992-04-03 | Thermomagnetic recording device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5954002A JPS5954002A (en) | 1984-03-28 |
| JP2519197B2 true JP2519197B2 (en) | 1996-07-31 |
Family
ID=15820729
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57165880A Expired - Lifetime JP2519197B2 (en) | 1982-09-21 | 1982-09-21 | Thermomagnetic recording device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2519197B2 (en) |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5837608B2 (en) * | 1978-03-15 | 1983-08-17 | 日本放送協会 | magnetic recording medium |
| JPS5724047A (en) * | 1980-07-21 | 1982-02-08 | Matsushita Electric Ind Co Ltd | Recorder and reproducer |
-
1982
- 1982-09-21 JP JP57165880A patent/JP2519197B2/en not_active Expired - Lifetime
Non-Patent Citations (1)
| Title |
|---|
| ＪａｐａｎｅｓｅＪｏｕｒｎａｌｏｆＡｐｐｌｉｅｄＰｈｙｓｉｃｓ．Ｖｏｌ．１８（１９７９）Ｓｕｐｐｌｅｍｅｎｔｅ１８−１ＰＰ．２３１−２３４ |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5954002A (en) | 1984-03-28 |
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