JPH034973B2 - - Google Patents
Info
- Publication number
- JPH034973B2 JPH034973B2 JP56070284A JP7028481A JPH034973B2 JP H034973 B2 JPH034973 B2 JP H034973B2 JP 56070284 A JP56070284 A JP 56070284A JP 7028481 A JP7028481 A JP 7028481A JP H034973 B2 JPH034973 B2 JP H034973B2
- Authority
- JP
- Japan
- Prior art keywords
- film
- reflective film
- magneto
- recording
- thin film
- 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
- 239000010408 film Substances 0.000 claims description 64
- 230000005291 magnetic effect Effects 0.000 claims description 14
- 239000000758 substrate Substances 0.000 claims description 11
- 239000010409 thin film Substances 0.000 claims description 11
- 238000003860 storage Methods 0.000 claims description 8
- 230000005415 magnetization Effects 0.000 claims description 2
- 230000015654 memory Effects 0.000 description 6
- 229910004298 SiO 2 Inorganic materials 0.000 description 5
- 239000000696 magnetic material Substances 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 239000012790 adhesive layer Substances 0.000 description 4
- 230000003287 optical effect Effects 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 239000011521 glass Substances 0.000 description 3
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000002223 garnet Substances 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- 239000010410 layer Substances 0.000 description 2
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 2
- 239000004926 polymethyl methacrylate Substances 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 230000005374 Kerr effect Effects 0.000 description 1
- 229910016629 MnBi Inorganic materials 0.000 description 1
- 229910010413 TiO 2 Inorganic materials 0.000 description 1
- 238000003486 chemical etching Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000001312 dry etching Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 239000002902 ferrimagnetic material Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 150000002910 rare earth metals Chemical class 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 229920003002 synthetic resin Polymers 0.000 description 1
- 239000000057 synthetic resin Substances 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
- 229910052725 zinc Inorganic materials 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
Description
【発明の詳細な説明】
本発明はレーザー光により情報の記録再生消去
を行う磁気光学記憶素子に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magneto-optical storage element that records, reproduces and erases information using laser light.
近年、高密度・大容量・高速アクセス等の種々
の要求を満足し得る光メモリ装置の研究開発が活
発に進められている。 In recent years, research and development of optical memory devices that can satisfy various demands such as high density, large capacity, and high speed access have been actively conducted.
各種光メモリ装置のうちでも特に記録材料とし
て垂直磁化膜を用いた磁気光学記憶装置は、不要
になつた情報を消去しその上に新しい情報を再記
録できるという特長があり広く注目されている。 Among various optical memory devices, magneto-optical storage devices that use a perpendicularly magnetized film as a recording material have attracted wide attention because of their ability to erase information that is no longer needed and re-record new information thereon.
しかし、上記の特長を有する反面、磁気光学記
憶素子は再生信号が小さいため、信号雑音比
（Ｓ／Ｎ）が良くないという欠点があつた。特に
磁気光学記憶素子からの反射光を利用して情報の
再生を行う、所謂カー効果再生方式においては磁
性体のカー回転角が小さいため、Ｓ／Ｎ比を高め
る事が困難であつた。そのため従来では記録媒体
である磁性材料を改良したり、或いは記録媒体上
にSiOやSiO2の誘電体膜を形成したりして、カー
回転角を高める工夫がなされていた。後者の例と
して、たとえばTbFe 磁性体薄膜上にSiO膜を
形成することによつてカー回転角が0.15度から
0.6度に増大した事が報告されている（IEEE
Trans on Mag Vol Mag−16 no5、1980
P1194）。しかしながら、このような磁性体膜上
への誘電体膜の形成による方法では、カー回転角
が増大する一方で反射光量が減退し（たとえば、
上記TbFeとSiOの例では反射光量が50％から10
％へ減少する）、その為実質的なＳ／Ｎ比の改善
にはならず理論値程の期待はできなかつた。又、
一方SiOやSiO2等の誘電体薄膜の形成では、磁性
体に腐蝕の恐れのある場合はその腐蝕の実質的な
防御となり得ない事や、記録ビツト径が1μｍ程
度であるため1μｍ程度の小さなほこりやゴミが
該誘電体薄膜に付着した場合は記録ビツト検出が
不可能になる事等のため実質的な記録素子とする
ためには厚さ0.5〜２mm程度のガラス又は透明樹
脂を使用する事が望ましい。しかし、そうする事
によりカー回転角の増大は期待できない。 However, although it has the above-mentioned features, the magneto-optical memory element has a drawback that the signal-to-noise ratio (S/N) is not good because the reproduced signal is small. In particular, in the so-called Kerr effect reproduction method in which information is reproduced using reflected light from a magneto-optical storage element, it has been difficult to increase the S/N ratio because the Kerr rotation angle of the magnetic material is small. Therefore, conventional efforts have been made to increase the Kerr rotation angle by improving the magnetic material of the recording medium or by forming a dielectric film of SiO or SiO 2 on the recording medium. As an example of the latter, for example, by forming a SiO film on a TbFe magnetic thin film, the Kerr rotation angle can be changed from 0.15 degrees.
It has been reported that the increase has increased to 0.6 degrees (IEEE
Trans on Mag Vol Mag−16 no5, 1980
P1194). However, in this method of forming a dielectric film on a magnetic film, the Kerr rotation angle increases while the amount of reflected light decreases (for example,
In the above example of TbFe and SiO, the amount of reflected light varies from 50% to 10%.
%), therefore, the S/N ratio was not substantially improved and could not be expected as much as the theoretical value. or,
On the other hand, forming a dielectric thin film such as SiO or SiO 2 cannot provide substantial protection against corrosion if there is a risk of corrosion in the magnetic material. If dust or dirt adheres to the dielectric thin film, it will become impossible to detect recorded bits, so glass or transparent resin with a thickness of about 0.5 to 2 mm should be used to make it a practical recording element. is desirable. However, by doing so, it cannot be expected that the Kerr rotation angle will increase.
一方最近では、ガーネツト基板の上にDyFe等
のアモルフアス磁性体を付け、DyFeに記録され
た情報をＳ／Ｎ比の良いガーネツトに転写し読み
出す方式等も提案されている（第４回日本応用磁
気学会学術講習会5aB−４）。しかし、その方式
では大面積の記憶素子にはなり得ず大容量メモリ
には適さない。 On the other hand, recently, a method has been proposed in which an amorphous magnetic material such as DyFe is attached to a garnet substrate and the information recorded on the DyFe is transferred to and read out from the garnet with a good S/N ratio. Academic Seminar 5aB-4). However, this method cannot provide a large-area storage element and is not suitable for large-capacity memories.
又以上の問題とは別に光メモリ装置は高密度記
録が基本的な条件であるため、その記録ビツト径
は上述したごとく1μｍ程度であり、従つて記録
再生・消去の過程でフオーカスサーボ、トラツク
サーボ等のサーボ技術が不可欠となる。さもない
と記録装置は複雑で、かつ精巧なものが必要とな
り、実用には適さなくなる。そして特にトラツク
サーボをかける場合にはフイリツプスMCA方式
のビデオデイスク装置の様にあらかじめ記録され
ている情報を再生するだけの装置とは異なり、磁
気光学記録装置では何等情報のない場所に新たに
信号を記録していく必要があり、そのためには信
号の記録トラツクと平行してサーボ用のガイドト
ラツクがある事が望ましい。 In addition to the above-mentioned problems, since high-density recording is the basic requirement for optical memory devices, the recording bit diameter is about 1 μm as mentioned above, and therefore the focus servo, track servo, etc. etc. servo technology is essential. Otherwise, the recording device would need to be complicated and sophisticated, making it unsuitable for practical use. In particular, when applying track servo, unlike a device such as a Philips MCA video disk device that only reproduces pre-recorded information, a magneto-optical recording device generates a new signal where there is no information. It is necessary to record signals, and for this purpose it is desirable to have a servo guide track in parallel with the signal recording track.
本発明は以上の点に鑑みなされたものであつて
反射光量を減らす事なく、磁気光学効果を増大さ
せるとともに、サーボ用のガイドトラツクをも得
る事を目的とする。 The present invention has been made in view of the above points, and an object of the present invention is to increase the magneto-optic effect without reducing the amount of reflected light, and to also obtain a guide track for servo.
次に本発明の具体的な実施例を図面を参照しな
がら詳説する。 Next, specific embodiments of the present invention will be explained in detail with reference to the drawings.
第１図は本発明の磁気光学記憶素子の一実施例
の一部拡大側面断面図である。ガラス又は
PMMA等の合成樹脂の基板１にGdTbFe、
TbDyFe等の希土類と遷移金属よりなるアモルフ
アスフエリ磁性体の垂直磁化膜２をスパツタリン
グや蒸着法等により形成する。更に該アモルフア
ス膜２の上からSiO2、SiO、MgF、TiO2等の透
明な誘電体膜３を形成し、該誘電体膜３の上から
Cu、Au、Ag、Zn、Sn等の反射層４を帯状に形
成する。アモルフアス膜２の最適膜厚は光メモリ
装置に使用するレーザ等の光の波長とアモルフア
ス膜２の種類と、反射膜４の種類により異なる
が、おおむね、50〜300Å程度である。具体的に
いえば、GdTbFe膜、HeNeレーザ、Cu反射膜の
組合せでは約150Å、又GdTbFe膜、8300Å半導
体レーザ、Cu反射膜では約200Åである。第２図
はGdTbFeの膜厚とカー回転角の関係をCuとAl
の反射膜に関して図示したものである。但し、使
用波長は6328Åである。GdTbFe膜だけのカー回
転角は0.27゜である事を考えると反射膜付き
GdTbFe膜の優位性は明らかである。AgやAuに
ついてもCuとほぼ同等の曲線を得ている。上記
透明な誘電体膜３はアモルフアス磁性体膜２にキ
ユリ点記録や補償点記録を行う場合、磁性体膜２
に加えられた熱が反射膜４に逃げないために断熱
層として設けたものであるが、この誘電体膜３の
膜厚によつてカー回転角は大きく異なる。従つ
て、磁性体膜２、誘電体膜３、反射膜４、使用波
長等によつて適当な膜厚を定めねばならない。例
えばGdTbFe磁性体膜、SiO2誘電体膜、Cu反射
膜を用い、HeNeレーザ波長6328Åの光を用いる
場合、SiO2膜厚は約2000Åが、又光源8300Åの
半導体レーザに変つた場合は、約2700Åが適当で
ある。 FIG. 1 is a partially enlarged side cross-sectional view of an embodiment of the magneto-optic storage element of the present invention. glass or
GdTbFe on the substrate 1 made of synthetic resin such as PMMA,
A perpendicular magnetization film 2 of an amorphous ferrimagnetic material made of a rare earth such as TbDyFe and a transition metal is formed by sputtering, vapor deposition, or the like. Furthermore, a transparent dielectric film 3 made of SiO 2 , SiO, MgF, TiO 2 or the like is formed on the amorphous film 2 , and then
A reflective layer 4 made of Cu, Au, Ag, Zn, Sn, etc. is formed in a band shape. The optimum thickness of the amorphous film 2 varies depending on the wavelength of light such as a laser used in the optical memory device, the type of the amorphous film 2, and the type of the reflective film 4, but is approximately 50 to 300 Å. Specifically, it is about 150 Å for a combination of a GdTbFe film, a HeNe laser, and a Cu reflective film, and about 200 Å for a combination of a GdTbFe film, an 8300 Å semiconductor laser, and a Cu reflective film. Figure 2 shows the relationship between GdTbFe film thickness and Kerr rotation angle for Cu and Al.
This is a diagram illustrating the reflective film of FIG. However, the wavelength used is 6328 Å. Considering that the Kerr rotation angle of the GdTbFe film alone is 0.27°, the reflective film is included.
The superiority of GdTbFe film is clear. Curves almost equivalent to those for Cu were obtained for Ag and Au. The above-mentioned transparent dielectric film 3 is used as the magnetic material film 3 when performing Kiyuri point recording or compensation point recording on the amorphous magnetic film 2.
Although the dielectric film 3 is provided as a heat insulating layer to prevent the heat applied to the dielectric film 3 from escaping to the reflective film 4, the Kerr rotation angle varies greatly depending on the thickness of the dielectric film 3. Therefore, appropriate film thicknesses must be determined depending on the magnetic film 2, dielectric film 3, reflective film 4, and the wavelength used. For example, if a GdTbFe magnetic film, SiO 2 dielectric film, and Cu reflective film are used and light with a HeNe laser wavelength of 6328 Å is used, the SiO 2 film thickness will be approximately 2000 Å, but if the light source is changed to a semiconductor laser with a wavelength of 8300 Å, the thickness will be approximately 2700 Å is suitable.
該誘電体膜３の膜厚は基本的にはλ／2n（使用
光源の波長をλ、誘電体膜３の屈折率をｎとす
る）の整数倍であれば良い。反射膜４は帯状のガ
イドトラツクを形成するとともに、トラツク番号
やトラツクをセクターに分ける場合に必要な情報
を断続した帯状トラツクとして入れても良い。又
接着層５はガイドトラツク付き反射膜４を保護す
るためのものであり、支持基板６と反射膜４を接
着するものであれば良い。 Basically, the thickness of the dielectric film 3 may be an integral multiple of λ/2n (where λ is the wavelength of the light source used and n is the refractive index of the dielectric film 3). The reflective film 4 forms a band-shaped guide track, and may also contain track numbers and information necessary for dividing the track into sectors as intermittent band-shaped tracks. Further, the adhesive layer 5 is for protecting the reflective film 4 with guide tracks, and any adhesive layer may be used as long as it adheres the supporting substrate 6 and the reflective film 4.
第３図は本発明に基づく磁気光学記憶素子の使
用例を説明する説明図である。 FIG. 3 is an explanatory diagram illustrating an example of use of the magneto-optic memory element based on the present invention.
集光レンズ１０で絞られたレーザ光９は反射膜
付きトラツク７へ照射され、該反射膜７に対応す
る磁性体膜の部分１１を記録トラツクとして情報
が記録・再生・消去される。同図の構造によれば
再生時においては反射膜７によりカー回転角が増
大され高いＳ／Ｎを得る事が出来、一方書込み時
には誘電体膜３により反射膜７へ熱が逃げるのを
防ぐので、少ないレーザパワーで記録ができる。
ガイドトラツクとしては反射膜のない部分８が使
用される。該部分８からの返り光は少いため、レ
ーザ光が記録トラツク１１からはずれた事を容易
に検出できる。 The laser beam 9 focused by the condenser lens 10 is irradiated onto the track 7 with a reflective film, and information is recorded, reproduced, and erased using the portion 11 of the magnetic film corresponding to the reflective film 7 as a recording track. According to the structure shown in the figure, during reproduction, the Kerr rotation angle is increased by the reflective film 7, making it possible to obtain a high S/N ratio.On the other hand, during writing, the dielectric film 3 prevents heat from escaping to the reflective film 7. , recording can be done with less laser power.
The portion 8 without a reflective coating is used as a guide track. Since the amount of light returned from the portion 8 is small, it is easy to detect that the laser beam has deviated from the recording track 11.
第４図は本発明に基づく磁気光学記憶素子の他
の実施例を示す一部側面断面図である。即ち、ガ
ラス又はPMMA等の樹脂基板１と磁性体膜２の
間にZnS、SiO、TiO2等該基板１の屈折率よりも
大きな屈折率を有する誘電体薄膜１２を入れたも
のである。他の部分は第１図の構成と同じであ
る。該誘電体薄膜１２は第１図の磁気光学記憶素
子よりも更にカー回転角を高めＳ／Ｎ比を改善す
るために導入されたものである。 FIG. 4 is a partial side sectional view showing another embodiment of the magneto-optic storage element according to the present invention. That is, a dielectric thin film 12 having a refractive index greater than that of the substrate 1, such as ZnS, SiO, TiO2, etc., is placed between a resin substrate 1 such as glass or PMMA and a magnetic film 2. The other parts are the same as the configuration shown in FIG. The dielectric thin film 12 is introduced in order to further increase the Kerr rotation angle and improve the S/N ratio compared to the magneto-optical memory element shown in FIG.
ここで本発明の主旨は磁気光学効果を増大させ
るための反射膜と該反射膜を帯状に形成する事で
ガイドトラツクを形成する事にある。従つて本発
明の主旨の範囲で他の種々の構成をとる事が出来
る。例えば磁性体膜はGdTbFeやDyTbFeの他に
GdBiFe、GdSnFe、GdPbFe、GdYFe、TbFe、
DyFe、MnBi、MnBiCu等の膜でも良い。又支
持基板６は接着層５が充分の強度を有するならば
不要であるし、又基板１から反射膜４までの構成
の素子を基板６に対し２枚はり合せ、表裏両面使
用の磁気光学記録素子としても良い。又本発明は
ガイドトラツクを有する反射膜の作成方法には依
らない事はもちろんであり、例えばケミカルエツ
チング、ドライエツチング等のエツチングやレー
ザ光によるカツチング法等をその製造に用いるこ
とが考えられる。 Here, the gist of the present invention is to form a guide track by forming a reflective film in order to increase the magneto-optic effect and forming the reflective film in a band shape. Therefore, various other configurations can be adopted within the scope of the spirit of the present invention. For example, magnetic films include GdTbFe and DyTbFe.
GdBiFe, GdSnFe, GdPbFe, GdYFe, TbFe,
A film of DyFe, MnBi, MnBiCu, etc. may also be used. Further, the supporting substrate 6 is not necessary if the adhesive layer 5 has sufficient strength, and magneto-optical recording that can be used on both the front and back surfaces is achieved by bonding two elements of the structure from the substrate 1 to the reflective film 4 to the substrate 6. It may also be used as an element. It goes without saying that the present invention does not depend on the method of producing a reflective film having guide tracks; for example, etching such as chemical etching, dry etching, cutting with laser light, etc. may be used for its production.
以上説明した如く本発明によれば、磁気光学効
果を増大せしめる反射膜を帯形状にすることによ
つて該反射膜の存在によりサーボ用のトラツキン
グ信号をも得ることができるものである。 As explained above, according to the present invention, by forming the reflective film that increases the magneto-optical effect into a band shape, it is possible to obtain a tracking signal for servo due to the presence of the reflective film.
第１図は本発明に係わる磁気光学記憶素子の一
実施例の一部拡大側面断面図、第２図はGdTbFe
膜の反射膜膜厚変化に対するKerr回転角依存性
を示すグラフ図、第３図は第１図の磁気光学記憶
素子にレーザーを照射した状態を示す一部拡大側
面断面図、第４図は本発明に係わる磁気光学記憶
素子の他の実施例の一部拡大側面断面図を示す。
図中、１：基板、２：アモルフアス磁性体膜、
３：誘電体膜、４：反射膜、５：接着層、６：支
持基板、９：レーザ光、１０：集光レンズ、１
１：記録トラツク、１２：誘電体薄膜。
FIG. 1 is a partially enlarged side sectional view of an embodiment of the magneto-optical memory element according to the present invention, and FIG. 2 is a GdTbFe
A graph showing Kerr rotation angle dependence on changes in the reflective film thickness of the film. Figure 3 is a partially enlarged side cross-sectional view showing the magneto-optical memory element in Figure 1 irradiated with a laser. Figure 4 is the main FIG. 6 shows a partially enlarged side cross-sectional view of another embodiment of the magneto-optic storage element according to the invention. In the figure, 1: substrate, 2: amorphous magnetic film,
3: Dielectric film, 4: Reflective film, 5: Adhesive layer, 6: Support substrate, 9: Laser light, 10: Condensing lens, 1
1: recording track, 12: dielectric thin film.
Claims (1)
有する磁性体薄膜を形成し、該磁性体薄膜の上部
に帯状の反射膜を形成するとともに、 前記磁性体薄膜の前記帯状の反射膜に対向する
部分を情報記録部とし、前記磁性体薄膜の前記帯
状の反射膜に対向しない部分を非情報記録部とし
たことを特徴とする磁気光学記憶素子。[Scope of Claims] 1. A magnetic thin film having an axis of easy magnetization perpendicular to the film surface is formed on a transparent substrate, a strip-shaped reflective film is formed on top of the magnetic thin film, and the magnetic thin film A magneto-optical storage element, characterized in that a portion of the magnetic thin film that faces the strip-shaped reflective film is an information recording portion, and a portion of the magnetic thin film that does not face the strip-shaped reflective film is a non-information recording portion.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7028481A JPS57183647A (en) | 1981-05-08 | 1981-05-08 | Magentrooptical storage element |
| US06/275,388 US4414650A (en) | 1980-06-23 | 1981-06-19 | Magneto-optic memory element |
| FR8112234A FR2485241B1 (en) | 1980-06-23 | 1981-06-22 | MAGNETO-OPTICAL MEMORY ELEMENT |
| DE3124573A DE3124573C2 (en) | 1980-06-23 | 1981-06-23 | Magneto-optical storage medium |
| GB8119345A GB2081537B (en) | 1980-06-23 | 1981-06-23 | Magneto-optic memory element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7028481A JPS57183647A (en) | 1981-05-08 | 1981-05-08 | Magentrooptical storage element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57183647A JPS57183647A (en) | 1982-11-12 |
| JPH034973B2 true JPH034973B2 (en) | 1991-01-24 |
Family
ID=13427023
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7028481A Granted JPS57183647A (en) | 1980-06-23 | 1981-05-08 | Magentrooptical storage element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57183647A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6391847A (en) * | 1986-10-03 | 1988-04-22 | Ricoh Co Ltd | Magneto-optical recording medium |
| JPH04364250A (en) * | 1991-09-26 | 1992-12-16 | Brother Ind Ltd | Optical recording medium |
| JP2790553B2 (en) * | 1991-10-25 | 1998-08-27 | シャープ株式会社 | Magneto-optical storage element |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56105344A (en) * | 1980-01-25 | 1981-08-21 | Fuji Photo Film Co Ltd | Photomagnetic recording medium |
-
1981
- 1981-05-08 JP JP7028481A patent/JPS57183647A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56105344A (en) * | 1980-01-25 | 1981-08-21 | Fuji Photo Film Co Ltd | Photomagnetic recording medium |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57183647A (en) | 1982-11-12 |
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