JP3180813B2 - Optical information recording medium - Google Patents
Optical information recording mediumInfo
- Publication number
- JP3180813B2 JP3180813B2 JP21883490A JP21883490A JP3180813B2 JP 3180813 B2 JP3180813 B2 JP 3180813B2 JP 21883490 A JP21883490 A JP 21883490A JP 21883490 A JP21883490 A JP 21883490A JP 3180813 B2 JP3180813 B2 JP 3180813B2
- Authority
- JP
- Japan
- Prior art keywords
- layer
- recording layer
- reflectance
- recording
- substrate
- 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.)
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Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は、熱履歴の違いにより誘起される相変化にと
もない光学定数が変化することを利用した情報の記録お
よび消去ができる記録媒体に関するものである。Description: TECHNICAL FIELD The present invention relates to a recording medium capable of recording and erasing information utilizing a change in an optical constant caused by a phase change induced by a difference in thermal history. It is.
（従来の技術） レーザ光を利用して情報の記録・再生を行う光ディス
クは、大容量、可搬型のファイルメモリとして注目され
ており、すでに、再生専用型、追記型、書換型が実用化
されている。オーバーライトが可能な方式の１つとし
て、相変化型光ディスクがある。相変化型光ディスクで
は、レーザ光照射による昇温、冷却の熱履歴の違いによ
って誘起される非晶質・結晶間などの相変化を利用して
記録・消却が行われ、これらの相変化にともなう光学定
数の変化が反射率の変化として再生されている。相変化
型光ディスクは、光磁気ディスクと比べ、オーバーライ
トが容易である、光学ヘッドの構造が単純であるなどの
特徴を有する。(Prior art) An optical disk for recording / reproducing information using a laser beam has attracted attention as a large-capacity, portable file memory, and a reproduction-only type, a write-once type, and a rewritable type have already been put to practical use. ing. As one of the methods capable of overwriting, there is a phase change optical disk. In a phase-change optical disk, recording / erasing is performed using a phase change between amorphous and crystal induced by a difference in heat history of temperature rise and cooling by laser beam irradiation, and these phase changes are accompanied. Changes in optical constants are reproduced as changes in reflectance. The phase change optical disk has features such as easy overwriting and a simple optical head structure as compared with the magneto-optical disk.
相変化型光ディスクでは、基板上に下地層２、記録層
３、保護層４、反射層５がこの順に設けられた第１図
（ｂ）に示すような４層構成が通常用いられる。反射層
５は入射光を効率よく使うという光学的観点および冷却
速度を向上させて非晶質化しやすくすることなど熱伝導
の観点の２つの観点から構成される。各層の膜厚は、記
録した部分と消去した部分との反射率の差がなるべく大
きく、吸収率の差がなるべく小さくなるように光学的に
最適化される。In a phase-change optical disk, a four-layer structure as shown in FIG. 1B in which an underlayer 2, a recording layer 3, a protective layer 4, and a reflective layer 5 are provided on a substrate in this order is usually used. The reflection layer 5 is configured from two viewpoints, that is, an optical viewpoint of using incident light efficiently and a heat conduction viewpoint of improving a cooling rate to facilitate amorphization. The film thickness of each layer is optically optimized so that the difference in reflectance between the recorded portion and the erased portion is as large as possible, and the difference in absorptance is as small as possible.
ここで吸収率の差が小さくなるようにとは、もし、吸
収率が記録された部分と消去部分とで異なった場合に
は、オーバーライト時の温度上昇が照射強度だけでは決
まらず、前の記録状態に依存してしまうため、オーバー
ライトしにくくなってしまうことより要求される条件で
ある。光学的な最適化条件は、 （１）成膜したままの状態での反射率が、５％以上ある
こと （２）結晶化にともなう反射率変化が15％以上あるこ （３）結晶化前後とも吸収率が60％以上あること （４）結晶化前後の吸収率変化が５％以下であることで
ある。Here, to make the difference in the absorptivity small means that if the absorptivity is different between the recorded part and the erased part, the temperature rise during overwriting is not determined only by the irradiation intensity, This is a required condition because it depends on the recording state, making it difficult to overwrite. The optical optimization conditions are: (1) the reflectivity in the state of film formation is 5% or more (2) the change in reflectivity due to crystallization is 15% or more (3) both before and after crystallization (4) Absorption rate change before and after crystallization is 5% or less.
反射層には通常A1、Auなどの金属が用いられる。しか
し、反射層に反射率の高い金属を用いた反射層構造にお
いては、結晶化前後の反射率の差がほぼそのまま吸収率
の差となり、各層の膜厚を調整することによって反射層
に吸収率の変化をなくすことが難しいという問題があっ
た。極端な場合として、反射率100％の反射層を考える
と、記録した部分と消去した部分の反射率の差はそのま
ま吸収率の差となってしまう。具体的として、第１図
（ｂ）に示すような、基板１上に下地層２、記録層３、
保護層４、反射層５を順次積層した構成について述べ
る。反射層５として反射率の高いAuを用いその膜厚を50
nmとした。Auは屈折率0.418、消衰係数5.13であり、ガ
ラス基板上に単層で50nm形成した場合の波長λ＝830nm
に対する基板入射の反射率は88.4％である。記録層３は
Ge19Sb38Te43とした。Ge19Sb38Te43は、スパッタしたま
まの状態で屈折率4.15、消衰係数1.00、結晶状態で屈折
率5.30、消衰係数2.51であった。下地層２および保護層
４は屈折率2.0のSi3N4とした。A metal such as A1, Au or the like is usually used for the reflective layer. However, in a reflective layer structure using a metal with high reflectivity for the reflective layer, the difference in reflectivity before and after crystallization is almost the same as the difference in absorptivity. There was a problem that it was difficult to eliminate the change of the. In an extreme case, when a reflection layer having a reflectance of 100% is considered, the difference between the reflectance of the recorded portion and the reflectance of the erased portion is directly the difference in the absorptance. Specifically, as shown in FIG. 1 (b), a base layer 2, a recording layer 3,
A configuration in which the protective layer 4 and the reflective layer 5 are sequentially laminated will be described. Au having high reflectivity is used as the reflective layer 5 and its thickness is set to 50.
nm. Au has a refractive index of 0.418 and an extinction coefficient of 5.13, and the wavelength λ = 830 nm when a 50 nm single layer is formed on a glass substrate.
Is 88.4%. The recording layer 3
Ge 19 Sb 38 Te 43 was used. Ge 19 Sb 38 Te 43 had a refractive index of 4.15 and an extinction coefficient of 1.00 in an as-sputtered state, and a refractive index of 5.30 and an extinction coefficient of 2.51 in a crystalline state. The underlayer 2 and the protective layer 4 were made of Si 3 N 4 having a refractive index of 2.0.
下地層２の膜厚を、波長λ＝830nm、下地層の屈折率
ｎ＝2.0に対してλ/2nの1/4に固定し、記録層及び保護
層の膜厚を変化させて反射率、吸収率を計算し、記録層
の膜厚をＸ軸に、保護層の膜厚をＹ軸にとって条件
（１）〜（４）をともに満たす領域を求めた。The thickness of the underlayer 2 is fixed to 1/4 of λ / 2n with respect to the wavelength λ = 830 nm and the refractive index n = 2.0 of the underlayer. The absorptance was calculated, and the area satisfying all of the conditions (1) to (4) was determined with the thickness of the recording layer on the X axis and the thickness of the protective layer on the Y axis.
条件（１）、（２）、（３）、（４）を満たす領域を
それぞれ第23図、第24図、第25図、第26図に示す。条件
（１）〜（３）をともに満たす領域を第27図に示す。第
24図と第26図を比較すると下地層２の膜厚がλ/2nの1/4
のときに条件（２）と（４）をともに満たす領域は存在
しない。また、下地層の膜厚を変えた場合にも条件
（２）と（４）をともに満たす領域は存在しなかった。Regions satisfying the conditions (1), (2), (3), and (4) are shown in FIGS. 23, 24, 25, and 26, respectively. FIG. 27 shows a region satisfying all of the conditions (1) to (3). No.
A comparison between FIG. 24 and FIG. 26 shows that the thickness of the underlayer 2 is 1/4 of λ / 2n.
At this time, there is no region that satisfies both the conditions (2) and (4). Further, even when the thickness of the underlayer was changed, there was no region satisfying both the conditions (2) and (4).
（発明が解決しようとする課題） 以上のように反射層に反射率の高い金属を用いた反射
層構成では、条件（２）と（４）をともに満たす構成が
存在しないため、条件（１）〜（４）をともに満たす構
成が存在しない。第27図に示すような条件（１）〜
（３）を満たす領域、すなわち、記録した部分と消去し
た部分とで反射率の変化が大きくなるような構成では吸
収率も変化してしまうことになる。この時、すでに信号
が記録されている部分に新たに信号を重ね書きする場合
に、温度上昇が照射強度だけでは決まらず、前の記録状
態に依存してしまうため、新たな信号が書き込みにく
い、前の信号が消え残りやすいなどの問題が生じてい
た。(Problems to be Solved by the Invention) As described above, in a reflective layer configuration using a metal having a high reflectivity for the reflective layer, there is no configuration that satisfies both the conditions (2) and (4). There is no configuration that satisfies both (4) and (4). Conditions (1) to as shown in FIG.
In a configuration where the change in the reflectance is large between the region satisfying (3), that is, the recorded portion and the erased portion, the absorptance also changes. At this time, when a new signal is overwritten on a portion where the signal has already been recorded, the temperature rise is not determined only by the irradiation intensity, but depends on the previous recording state. There was a problem that the previous signal easily disappeared.
また、反射層に反射率の高い材料を用いた場合、媒体
全体での反射率、吸収率の膜厚依存が大きくなり、成膜
のマージンが小さくなるという問題もあった。Further, when a material having a high reflectivity is used for the reflective layer, there is a problem that the reflectivity and the absorptivity of the entire medium depend on the film thickness, and the margin for film formation is reduced.
本発明の目的は、前の記録状態にかかわらず重ね書き
が容易にでき、かつ成膜のマージンの大きい光学的情報
記録媒体を提供することにある。SUMMARY OF THE INVENTION An object of the present invention is to provide an optical information recording medium capable of easily overwriting regardless of a previous recording state and having a large film formation margin.
（課題を解決するための手段） 本発明による光学的情報記録媒体は、基板上に、レー
ザ光の照射による昇温、冷却の熱履歴の違いにより光学
的性質の変化する記録層を備え、この記録層上に、ガラ
ス基板上に単層で形成した場合の基板側から入射した光
に対する反射率が25％以上70％以下の反射層を設けたこ
とを特徴としている。(Means for Solving the Problems) An optical information recording medium according to the present invention includes, on a substrate, a recording layer whose optical properties change due to a difference in heat history of temperature rise and cooling by laser beam irradiation. On the recording layer, a reflective layer having a reflectance of 25% or more and 70% or less for light incident from the substrate side when formed as a single layer on a glass substrate is provided.
こうした、反射層として、消衰係数ｋが1.0以上でガ
ラス基板上に単層で350/k［nm］以上形成した場合の基
板入射の反射率が70％以下の物質、例えば、Ti、Cr、M
o、Ｗ、Co、Ni、Pd、Ptなどの金属を用いることができ
る。これらは単体で用いることもできるし、熱伝導度の
調整、隣接する層との付着力向上などを目的に、添加物
を加えたり、合金化して用いることもできる。Such a reflective layer is a substance having an extinction coefficient k of 1.0 or more and a substrate incident reflectance of 70% or less when a single layer is formed on a glass substrate at 350 / k [nm] or more, such as Ti, Cr, M
Metals such as o, W, Co, Ni, Pd, and Pt can be used. These may be used alone, or may be added or alloyed for the purpose of adjusting the thermal conductivity, improving the adhesion to an adjacent layer, and the like.
また、単体では反射率が70％以上の物質に、添加物を
加えたり、合金化して反射率を70％以下に調整して用い
ることもできる。In addition, when used alone, an additive can be added to a substance having a reflectance of 70% or more or alloyed to adjust the reflectance to 70% or less.
また、反射層として、消衰係数ｋが1.0以上でありか
つガラス基板上に単層で350/k［nm］以上形成した場合
の基板入射の反射率が70％以上の物質を用いる場合に
は、消衰係数ｋに対して反射層の膜厚ｄ［nm］を350/k
［nm］未満の適当な値に設定することにより、その反射
率を25％から70％の範囲にすることができる。こうした
物質として例えばRh、Cu、Au、A1、Inなどの金属があげ
られる。When a substance having an extinction coefficient k of 1.0 or more and a single layer of 350 / k [nm] or more formed on a glass substrate and having a substrate incident reflectance of 70% or more is used as the reflective layer. The thickness d [nm] of the reflective layer to 350 / k for the extinction coefficient k
By setting an appropriate value of less than [nm], the reflectance can be in the range of 25% to 70%. Examples of such a substance include metals such as Rh, Cu, Au, A1, and In.
さらに、屈折率2.5以上で消衰係数が0.3以下の物質も
反射層として利用することができる。こうした物質とし
て、TiO2、Fe2O3、Bi2O3などの酸化物、CdS、Sb2S3、Zn
Se、CdTeなどのカルコゲナイド、Ge、Siなどの半導体が
あげられる。この時、反射層の膜厚ｄ［nm］は再生用の
レーザの波長λ［nm］、反射層の屈折率ｎに対して、 ｄ＝λ/4n＋ｉ×（λ/2n）±λ/8n（ｉ＝1,2,3,…） の範囲にあることが望ましい。これは、この膜厚におい
て、反射率が大きくなるためである。上記の材料のなか
でも、Siは熱拡散率がほぼAlと同等であり、熱伝導層と
しての役割も果たすことができ、特に望ましい。Further, a substance having a refractive index of 2.5 or more and an extinction coefficient of 0.3 or less can also be used as the reflection layer. Such materials include oxides such as TiO 2 , Fe 2 O 3 , Bi 2 O 3 , CdS, Sb 2 S 3 , Zn
Examples include chalcogenides such as Se and CdTe, and semiconductors such as Ge and Si. At this time, the film thickness d [nm] of the reflective layer is d = λ / 4n + i × (λ / 2n) ± λ / 8n (refractive index n of the reflective layer) with respect to the wavelength λ [nm] of the reproducing laser. i = 1, 2, 3,...). This is because the reflectance increases at this film thickness. Among the above-mentioned materials, Si has a thermal diffusivity substantially equal to that of Al and can also serve as a heat conductive layer, and is particularly desirable.
したがって本発明の特徴は、基板上に、下地層と、レ
ーザ光の照射による昇温、冷却の熱履歴の違いにより光
学的性質の変化する記録層と、保護層と、反射層とを順
次備えた光学的情報記録媒体において、前記記録層が成
膜したままの状態での前記光学的情報記録媒体の基板側
から入射したときの反射率が５％以上であり、前記記録
層を成膜したままの状態から結晶化させた時の前記光学
的情報記録媒体の基板側から入射したときの反射率の変
化が15％以上であり、前記記録層を成膜したままの状態
と前記記録層が結晶化した状態における前記光学的情報
記録媒体の前記記録層の吸収率が60％以上であり、前記
記録層を成膜したままの状態から結晶化させた時の前記
光学的情報記録媒体の前記記録層の吸収率の変化が５％
以下であり、前記反射層がSiであり、前記Siによる前記
反射層がガラス基板上に単層で形成された場合に基板側
から入射した光に対する反射率が25％以上70％以下であ
る光学的情報記録媒体にある。Therefore, a feature of the present invention is that a substrate is provided with a base layer, a recording layer whose optical properties change due to a difference in heat history of temperature rise and cooling by irradiation with laser light, a protective layer, and a reflective layer. In the optical information recording medium, the reflectance was 5% or more when incident from the substrate side of the optical information recording medium in a state where the recording layer was formed, and the recording layer was formed. The change in reflectance when incident from the substrate side of the optical information recording medium when crystallized from the as-is state is 15% or more. The absorption rate of the recording layer of the optical information recording medium in the crystallized state is 60% or more, and the optical information recording medium of the optical information recording medium when crystallized from a state in which the recording layer is formed is formed. 5% change in the absorption rate of the recording layer
Wherein the reflective layer is Si, and the reflectivity for light incident from the substrate side is 25% or more and 70% or less when the reflective layer of Si is formed as a single layer on a glass substrate. Information recording medium.
（作用） 極端に反射層の反射率が高い場合として反射率100％
の場合を考えると、記録した部分と消去した部分の反射
率の差はそのまま吸収率の差になってしまい、媒体構成
の光学的な最適化ができないことから、反射層の反射率
に上限が存在することが推定される。逆に反射層の反射
率が低い場合、記録層を透過する光を利用できなくなる
ため、特に記録層の膜厚が薄いときに吸収率を大きくと
れなくなる。(Function) 100% reflectance when the reflectance of the reflective layer is extremely high
Considering the case of (1), the difference in reflectance between the recorded portion and the erased portion becomes the difference in absorptance as it is, and optical optimization of the medium configuration cannot be performed. It is presumed to be present. Conversely, when the reflectance of the reflective layer is low, light transmitted through the recording layer cannot be used, so that the absorption cannot be increased particularly when the thickness of the recording layer is small.
そこで、第１図（ｂ）に示すような、基板１上に下地
層２、記録層３、保護層４、反射層５を順次積層した構
成について、反射層５の反射率を10％から88％の範囲で
変化させて媒体構成の光学的な最適化を行った。反射層
はAu（屈折率0.418、消衰係数5.13）とし、所望の反射
率が得られるように膜厚を設定した。記録層３はGe19Sb
38Te43とした。下地層２および保護層４は屈折率2.0のS
i3N4とした。波長λ＝830nm、下地層の屈折率ｎ＝2.0に
対して、下地層の膜厚を、反射層の反射率が10％以上46
％以下ではλ/2nの5/8に、反射層の反射率が47％以上88
％以下ではλ/2nの1/4にそれぞれ固定し、記録層３及び
保護層４の膜厚を変化させて基板側から光を入射した時
の反射率、記録層３の吸収率を計算し、記録層の膜厚を
Ｘ軸に、保護層の膜厚をＹ軸にとって条件（１）〜
（４）をともに満たす領域を求めた。Therefore, as shown in FIG. 1 (b), in a configuration in which the base layer 2, the recording layer 3, the protective layer 4, and the reflective layer 5 are sequentially laminated on the substrate 1, the reflectance of the reflective layer 5 is increased from 10% to 88%. %, And the medium configuration was optically optimized. The reflective layer was made of Au (refractive index: 0.418, extinction coefficient: 5.13), and the film thickness was set so as to obtain a desired reflectance. The recording layer 3 is Ge 19 Sb
38 Te 43 . The underlayer 2 and the protective layer 4 are made of S having a refractive index of 2.0.
i 3 N 4 When the wavelength λ is 830 nm and the refractive index of the underlayer is n = 2.0, the thickness of the underlayer is set to 10% or more.
% Or less, the reflectivity of the reflective layer is 47% to 88, which is 5/8 of λ / 2n.
% Or less, it is fixed to 1/4 of λ / 2n, and the film thickness of the recording layer 3 and the protective layer 4 is changed to calculate the reflectance when the light is incident from the substrate side and the absorptance of the recording layer 3. When the thickness of the recording layer is set on the X axis and the thickness of the protective layer is set on the Y axis, conditions (1) to
An area satisfying both (4) was determined.
反射層の反射率が23％、25％、38％、40％、47％、65
％、70％、73％のときに条件（１）〜（４）をともに満
たす領域をそれぞれ第15図、第16図、第17図、第18図、
第19図、第20図、第21図、第22図に示す。反射層の反射
率が25％以上70％以下の場合には、条件（１）〜（４）
をともに満たす領域が記録層の膜厚で30nm近傍及び90nm
近傍に存在する。なかでも反射層の反射率が40％〜65％
の範囲には、条件（１）〜（４）をともに満たす領域が
記録層膜厚で30nm近傍及び90nm近傍にかけて連続的にと
れ、特に望ましいことがわかった。反射率が70％より大
きい場合には、条件（２）を満たす領域と条件（４）を
満たす領域の重なりが非常に狭くなるため、条件（１）
〜（４）をともに満たす領域が存在しなくなる。反射層
の反射率が25％未満では、記録層の膜厚が薄い場合に吸
収率が小さくなってしまい、条件（３）を満たす領域が
狭くなるため、記録層の膜厚が30nm近傍に条件（１）〜
（４）をともに満たす領域が存在しなくなる。Reflectivity of reflective layer is 23%, 25%, 38%, 40%, 47%, 65
15, FIG. 16, FIG. 17, FIG. 18, the regions satisfying all of the conditions (1) to (4) at%, 70%, and 73%, respectively.
These are shown in FIG. 19, FIG. 20, FIG. 21, and FIG. When the reflectivity of the reflective layer is 25% or more and 70% or less, conditions (1) to (4)
Are both around 30 nm and 90 nm in the thickness of the recording layer.
Present nearby. Above all, the reflectance of the reflective layer is 40% to 65%
In the range, the region satisfying all of the conditions (1) to (4) can be continuously obtained in the vicinity of the recording layer thickness of about 30 nm and about 90 nm. When the reflectance is greater than 70%, the overlap between the region satisfying the condition (2) and the region satisfying the condition (4) is very narrow, and therefore, the condition (1)
There is no region that satisfies (4). If the reflectivity of the reflective layer is less than 25%, the absorptance becomes small when the thickness of the recording layer is small, and the area satisfying the condition (3) becomes narrow. (1)-
There is no region satisfying both (4).
以上では、下地層２、保護層４をSi3N4としたが、こ
れはSi3N4に限定されるものでなく、屈折率が2.0であれ
ば成立するものである。In the above, the underlying layer 2 and the protective layer 4 are made of Si 3 N 4 , but this is not limited to Si 3 N 4, and the condition is satisfied if the refractive index is 2.0.
（実施例） 以下に本発明を実施例により、詳細に説明する。(Example) Hereinafter, the present invention will be described in detail with reference to examples.
第１図（ａ）は本発明による光記録媒体の基本構成の
断面図である。第１図（ａ）では透明な基板１の上に記
録層３、反射層５が順次が形成されている。基板として
はガラスやポリメタクリル酸メチル（PMMA）、ポリカー
ボネイト（PC）またはエポキシなどの透明樹脂が用いら
れる。この基板にはあらかじめトラッキングサーボ用の
溝やピットが形成されたものも用いられる。記録層とし
ては、レーザ光の照射などによる昇温、冷却の熱履歴の
違いにより、光学定数の変化を生じる物質、例えば、S
e、Teなどのカルコゲン系元素を含む化合物が用いられ
る。記録層の保護のため、実際には第１図（ｂ）に示す
ように、記録層をはさみ込む形で下地層２と保護層４と
を形成することが望ましい。これらは光の干渉により読
み出し信号を大きくする干渉層としても用いられるた
め、所望の膜厚に設定されることが望ましい。下地層２
および保護層４としては透明なSi3N4またはAlNなどの窒
化物やSiO、SiO2、Ta2O5などの酸化物である誘電体が使
用される。FIG. 1 (a) is a sectional view of the basic structure of an optical recording medium according to the present invention. In FIG. 1 (a), a recording layer 3 and a reflective layer 5 are sequentially formed on a transparent substrate 1. As the substrate, a transparent resin such as glass, polymethyl methacrylate (PMMA), polycarbonate (PC), or epoxy is used. A substrate on which grooves or pits for tracking servo are formed in advance is used. As the recording layer, a substance that changes the optical constant due to a difference in the thermal history of temperature rise and cooling due to irradiation with laser light, for example, S
Compounds containing chalcogen elements such as e and Te are used. In order to protect the recording layer, it is actually desirable to form the underlayer 2 and the protective layer 4 so as to sandwich the recording layer as shown in FIG. 1 (b). Since these are also used as an interference layer for increasing a read signal by light interference, it is desirable to set the film thickness to a desired value. Underlayer 2
The protective layer 4 is made of a transparent nitride such as Si 3 N 4 or AlN, or a dielectric such as an oxide such as SiO, SiO 2 or Ta 2 O 5 .
第１図（ｂ）に示すような、基板１上に下地層２、記
録層３、保護層４、反射層５を順次積層した構成につい
て、光学的に各層の膜厚の最適化を行い、その結果に従
ってPC基板上に成膜を行い、光学特性を測定した。As shown in FIG. 1 (b), for a configuration in which a base layer 2, a recording layer 3, a protective layer 4, and a reflective layer 5 are sequentially laminated on a substrate 1, the thickness of each layer is optically optimized. According to the results, a film was formed on a PC substrate, and the optical characteristics were measured.
まず、反射層５として消衰係数1.0以上でガラス基板
上に単層で350/k［nm］以上形成した場合の基板入射の
反射率が70％以下の物質を用いる場合の例として、Tiを
用いた場合について述べる。Tiをガラス基板上に単層で
100nm形成した場合の基板側からの入射光に対する反射
率は48％である。記録層３はGe19Sb38Te43とした。下地
層２および保護層４には屈折率2.0のSi3N4を用いた。波
長λ＝830nm、下地層の屈折率ｎ＝2.0に対して、下地層
の膜厚をλ/2nの5/8に固定し、記録層３及び保護層４の
膜厚を変化させて基板入射の反率、記録層３の吸収率を
計算し、記録層の膜厚をＸ軸に、保護層の膜厚をＹ軸に
とって条件（１）〜（４）をともに満たす領域を求め
た。条件（１）、（２）、（３）、（４）を満たす領域
をそれぞれ第３図、第４図、第５図、第６図に示す。こ
れらから条件（１）〜（４）をともに満たす領域を求め
た結果を第２図に示す。これらの領域から光学的に最適
化された媒体構成の具体例を第１表に示す。First, as an example of using a substance having a substrate incidence reflectance of 70% or less when a single layer of 350 / k [nm] or more is formed on a glass substrate with a extinction coefficient of 1.0 or more as a reflective layer 5, Ti is used. The case of using is described. Ti in a single layer on a glass substrate
The reflectivity with respect to the incident light from the substrate side when formed to 100 nm is 48%. The recording layer 3 was Ge 19 Sb 38 Te 43 . For the underlayer 2 and the protective layer 4, Si 3 N 4 having a refractive index of 2.0 was used. For a wavelength λ = 830 nm and a refractive index of the underlayer n = 2.0, the thickness of the underlayer is fixed to 5/8 of λ / 2n, and the film thickness of the recording layer 3 and the protective layer 4 is changed to be incident on the substrate. And the absorptance of the recording layer 3 were calculated, and the area satisfying all of the conditions (1) to (4) was determined with the thickness of the recording layer on the X axis and the thickness of the protective layer on the Y axis. Regions satisfying the conditions (1), (2), (3), and (4) are shown in FIGS. 3, 4, 5, and 6, respectively. FIG. 2 shows the result of obtaining a region satisfying all of the conditions (1) to (4) from these. Table 1 shows specific examples of media configurations that are optically optimized from these regions.
以下、実施例１〜３に従ってPC基板上に成膜を行い、
光学特性を測定した結果を述べる。記録層３のGe19Sb38
Te43はスパッタ法により成膜した。下地層２および保護
層４のSi3N4は反応性スパッタ法により成膜した。反射
層５は真空蒸着法により成膜した。 Hereinafter, a film is formed on a PC substrate according to Examples 1 to 3,
The results of measuring the optical characteristics will be described. Ge 19 Sb 38 of the recording layer 3
Te 43 was formed by a sputtering method. Si 3 N 4 of the underlayer 2 and the protective layer 4 was formed by a reactive sputtering method. The reflection layer 5 was formed by a vacuum evaporation method.
作成した試料の波長λ＝830nmに対する基板入射の反
射率Ｒ、透過率Ｔ、吸収率Ａを測定した結果を第２表に
示す。スパッタしたままの状態と結晶化した状態につい
て測定した。ここで、反射層５でも吸収があるので、吸
収率Ａは記録層３と反射層５の両方の吸収率の合計であ
る。Table 2 shows the measurement results of the reflectance R, the transmittance T, and the absorptance A of the sample thus prepared at a wavelength of λ = 830 nm, which were incident on the substrate. The measurement was performed on the as-sputtered state and the crystallized state. Here, since the reflection layer 5 also has absorption, the absorption rate A is the sum of the absorption rates of both the recording layer 3 and the reflection layer 5.
実施例１および実施例１と同じ構成で反射層をAuとし
てディスクを線速度11.3m/sで回転させ、周波数3.7MH
z、デューティ50％の信号を記録した上に周波数2.8MH
z、デューティ50％の信号を重ね書きして、3.7HMzの信
号の消去率を測定した。なお、両ディスクとも、あらか
じめ記録層を結晶化させてから評価を行った。反射層が
Auのディスクの場合、消去パワーが6.3mWで消去率が30.
3dBと最大になり、消去パワーが5.8mWから7.3mWにおい
て消去率が25dB以上となった。これに対して、反射層が
Tiである実施例１のディスクでは6.5mWで消去率が34.2d
Bと最大になり、消去パワー4.0mWから8.7mWにおいて消
去率が25dB以上となり、重ね書き時の消去特性が向上し
た。 The disk was rotated at a linear velocity of 11.3 m / s with the reflective layer made of Au and the same configuration as in Example 1 and Example 1 and a frequency of 3.7 MHz.
z, a signal of 50% duty is recorded and the frequency is 2.8MHZ
The signal of z, 50% duty was overwritten, and the erasure rate of the signal of 3.7HMz was measured. For both disks, evaluation was performed after the recording layer was crystallized in advance. The reflective layer
For Au disks, the erasing power is 6.3mW and the erasing rate is 30.
The maximum was 3 dB, and the erasing rate was 25 dB or more when the erasing power was 5.8 mW to 7.3 mW. In contrast, the reflective layer
The erasure rate was 34.2 d at 6.5 mW for the disk of Example 1 which was Ti.
B, the erasure rate was 25 dB or more from 4.0 mW to 8.7 mW in erasing power, and the erasing characteristics during overwriting were improved.
また、反射層がAuのディスクでは記録層が結晶化され
ていて未記録の部分に記録する場合と、すでに記録して
あるところに重ね書きを行う場合とで、最適記録消去パ
ワーが変わってしまうという問題があった。これは、未
記録の部分とすでに記録してある部分とで記録層の平均
的な吸収率が異なるためである。一方、反射層がTiであ
る実施例１のディスクではこうした問題はなく同じ条件
で記録を行うことができた。In addition, in the case of a disk having a reflective layer of Au, the optimum recording / erasing power varies depending on whether the recording layer is crystallized and recording is performed on an unrecorded portion, or when overwriting is performed on an already recorded portion. There was a problem. This is because the average absorptivity of the recording layer differs between the unrecorded portion and the already recorded portion. On the other hand, in the disk of Example 1 in which the reflective layer was Ti, there was no such a problem, and recording could be performed under the same conditions.
次に、反射層５としてバルクの反射率が70％以上の金
属を膜厚を薄くして用いる場合の一例として、Auを用い
てその膜厚を10nmとした場合について述べる。Auをガラ
ス基板上に単層で10nm形成した場合、基板入射の反射率
は35.7％になる。記録層３はGe19Sb38Te43とした。下地
層２および保護層４にはSi3N4を用いた。波長λ＝830n
m、下地層の屈折率ｎ＝2.0に対して、下地層の膜厚をλ
/2nの5/8に固定し、記録層３及び保護層４の膜厚を変化
させて基板入射の反射率、記録層３の吸収率を計算し、
条件（１）〜（４）をともに満たす領域を反射層がTiの
場合と同様にして求めた。（１）〜（４）をともに満た
す領域を第７図に示す。同様にして下地層２の膜厚がλ
/2nの1/4および3/4の場合に条件（１）〜（４）をとも
に満たす領域を求めた結果を第８図、第９図に示す。こ
れらの領域から光学的に最適化された媒体構成の具体例
を第３表に示す。Next, as an example of a case where a metal having a bulk reflectivity of 70% or more is used as the reflective layer 5 with a reduced thickness, a case where the thickness is 10 nm using Au will be described. When Au is formed as a single layer on a glass substrate to a thickness of 10 nm, the reflectance at the substrate incidence is 35.7%. The recording layer 3 was Ge 19 Sb 38 Te 43 . Si 3 N 4 was used for the underlayer 2 and the protective layer 4. Wavelength λ = 830n
m and the refractive index of the underlayer n = 2.0, the thickness of the underlayer is λ
/ 2n is fixed at 5/8, the film thickness of the recording layer 3 and the protective layer 4 is changed, and the reflectance at the substrate incidence and the absorptance of the recording layer 3 are calculated.
A region satisfying all of the conditions (1) to (4) was determined in the same manner as in the case where the reflective layer was Ti. FIG. 7 shows regions satisfying all of (1) to (4). Similarly, the thickness of the underlayer 2 is λ
FIG. 8 and FIG. 9 show the results of obtaining a region satisfying both of the conditions (1) to (4) in the case of 1/4 and 3/4 of / 2n. Table 3 shows specific examples of optically optimized medium configurations from these regions.
以下、実施例４〜７に従ってPC基板上に成膜を行い、
光学特性を測定した結果を述べる。記録層３の Ge19Sb38Te43はスパッタ法により成膜した。下地層２お
よび保護層４のSi3N4は反応性スパッタ法により成膜し
た。反射層５は真空蒸着法により成膜した。Hereinafter, a film is formed on a PC substrate according to Examples 4 to 7,
The results of measuring the optical characteristics will be described. Of the recording layer 3 Ge 19 Sb 38 Te 43 was formed by a sputtering method. Si 3 N 4 of the underlayer 2 and the protective layer 4 were formed by a reactive sputtering method. The reflection layer 5 was formed by a vacuum evaporation method.
作成した試料の波長λ＝830nmに対する基板入射の反
射率Ｒ、透過率Ｔ、吸収率Ａを測定した結果を第４表に
示す。スパッタしたままの状態と結晶化した状態につい
て測定した。ここで、反射層５でも吸収があるので、吸
収率Ａは記録層３と反射層５の両方の吸収率の合計であ
る。反射層５をガラス基板上に単層で10nm形成した場
合、反射率35.7％、透過率47.9％、吸収率16.4％であっ
た。これをもとに前記試料の透過率から反射層５での吸
収を推定して記録層３での吸収率を求めたのがＡ′であ
る。Table 4 shows the measurement results of the reflectance R, the transmittance T, and the absorptance A of the sample thus prepared at a wavelength of λ = 830 nm when the substrate was incident. The measurement was performed on the as-sputtered state and the crystallized state. Here, since the reflection layer 5 also has absorption, the absorption rate A is the sum of the absorption rates of both the recording layer 3 and the reflection layer 5. When the reflective layer 5 was formed as a single layer of 10 nm on a glass substrate, the reflectance was 35.7%, the transmittance was 47.9%, and the absorption was 16.4%. Based on this, A ′ was obtained by estimating the absorption in the reflective layer 5 from the transmittance of the sample and calculating the absorption in the recording layer 3.
続いて、反射層５として、屈折率2.5以上で消衰係数
0.3以下の物質を用いる場合の一例として、反射層５にS
iを用いる場合について述べる。スパッタ法により成膜
したSiは屈折率3.5、消衰係数0.10であったので、再生
用レーザの波長λ＝830nm、Siの屈折率ｎ＝3.5に対し
て、反射層５の膜厚をλ/4n＝60nmとした、記録層３はG
e19Sb38Te43とした。下地層２および保護層４にはSi3N4
を用いた。 Subsequently, as the reflection layer 5, the extinction coefficient at a refractive index of 2.5 or more
As an example in the case of using a substance of 0.3 or less, S
The case where i is used will be described. Since the Si film formed by the sputtering method had a refractive index of 3.5 and an extinction coefficient of 0.10, the thickness of the reflective layer 5 was set to λ / 830 with respect to the wavelength of the reproducing laser λ = 830 nm and the refractive index of Si = 3.5. 4n = 60nm, recording layer 3 is G
e 19 Sb 38 Te 43 was selected. The underlayer 2 and the protective layer 4 are made of Si 3 N 4
Was used.
光学的最適化の条件（１）〜（４）をともに満たす領
域は下地層２の膜厚がλ/2nの2/8、5/8、6/8のときに広
く得られた。これらを各々第10図、第11図、第12図に示
す。これらの領域から光学的に最適化された媒体構成の
具体例を第５表に示す。Regions satisfying all of the optical optimization conditions (1) to (4) were obtained widely when the thickness of the underlayer 2 was 2/8, 5/8, and 6/8 of λ / 2n. These are shown in FIGS. 10, 11 and 12, respectively. Table 5 shows specific examples of media configurations that are optically optimized from these regions.
このように反射層としてSiのような高屈折率を有しほ
とんど吸収のないものを用いた場合にも媒体構成の光学
的な最適化を行うことができる。また、熱特性について
も、Siは熱拡散率がほぼAlと同等であり、熱伝導層とし
ての役割も果たすことができる、熱膨張係数が小さく、
記録、消去時の変形が小さいなどの点で優れている。さ
らに、Siは金属に比べ耐候性に優れているといった特徴
を有している。 As described above, even when a reflective layer having a high refractive index such as Si and having little absorption is used, the optical configuration of the medium can be optimized. Regarding thermal properties, Si has a thermal diffusivity almost equal to that of Al, and can also serve as a heat conductive layer.
It is excellent in that deformation during recording and erasing is small. Further, Si has a feature that it has better weather resistance than metal.
以下、実施例８〜13に従ってPC基板上に成膜を行い、
光学特性を測定した結果を述べる。記録層３のGe19Sb38
Te43はスパッタ法により成膜した。下地層２および保護
層４のSi3N4は反応性スパッタ法により成膜した。反射
層５はスパッタ法により成膜した。Hereinafter, a film is formed on a PC substrate according to Examples 8 to 13,
The results of measuring the optical characteristics will be described. Ge 19 Sb 38 of the recording layer 3
Te 43 was formed by a sputtering method. Si 3 N 4 of the underlayer 2 and the protective layer 4 was formed by a reactive sputtering method. The reflection layer 5 was formed by a sputtering method.
作成した試料の波長λ＝830nmに対する基板入射の反
射率Ｒ、透過率Ｔ、吸収率Ａを測定した結果を第６表に
示す。スパッタしたままの状態と窒素雰囲気中で2500℃
まで昇温して結晶化した状態について測定した。ここ
で、反射層５でも吸収があるので、吸収率Ａは記録層３
と反射層５の両方の吸収率の合計である。反射層５をガ
ラス基板上に単層で60nm形成した場合、反射率54.7％、
透過率38.9％、吸収率6.4％であった。これをもとに前
記試料の透過率から反射層５での吸収を推定して記録層
３での吸収率を求めたのがＡ′である。Table 6 shows the measurement results of the reflectance R, the transmittance T, and the absorptance A of the sample thus prepared when the substrate was incident on the substrate at a wavelength λ = 830 nm. 2500 ° C in a sputtered state and in a nitrogen atmosphere
The temperature was raised to and crystallized. Here, since the reflection layer 5 also has absorption, the absorption rate A is
It is the sum of the absorptivity of both the reflection layer 5 and the reflection layer 5. When the reflecting layer 5 is formed as a single layer on a glass substrate at 60 nm, the reflectance is 54.7%,
The transmittance was 38.9% and the absorption was 6.4%. Based on this, A ′ was obtained by estimating the absorption in the reflective layer 5 from the transmittance of the sample and calculating the absorption in the recording layer 3.
反射層５にSiを用いた他の例として、下地層に屈折率
2.0の(ZnS)0.8(SiO2)0.2を、保護層に屈折率1.9のAlNを
用いた場合について述べる。記録層３はGe19Sb38Te43と
した。波長λ＝830nm、下地層の屈折率ｎ＝2.0に対し
て、下地層の膜厚をλ/2nの5/8に固定し、記録層３及び
保護層４の膜厚を変化させて基板入射の反射率、記録層
３の吸収率を計算し、条件（１）〜（４）をともに満た
す領域を反射層がTiの場合と同様にして求めた。（１）
〜（４）をともに満たす領域を第13図に示す。これらの
領域から光学的に最適化された媒体構成の具体例を第７
表に示す。 As another example using Si for the reflective layer 5, the refractive index is
The case of using (ZnS) 0.8 (SiO 2 ) 0.2 of 2.0 and AlN of refractive index 1.9 for the protective layer will be described. The recording layer 3 was Ge 19 Sb 38 Te 43 . For a wavelength λ = 830 nm and a refractive index of the underlayer n = 2.0, the thickness of the underlayer is fixed to 5/8 of λ / 2n, and the film thickness of the recording layer 3 and the protective layer 4 is changed to be incident on the substrate. And the absorptance of the recording layer 3 were calculated, and a region satisfying all of the conditions (1) to (4) was determined in the same manner as in the case where the reflective layer was Ti. (1)
FIG. 13 shows a region that satisfies (4) to (4). A specific example of an optically optimized medium configuration from these regions is described in the seventh section.
It is shown in the table.
以下、実施例14、15に従ってPC基板上に成膜を行い、
光学特性を測定した結果を述べる。記録層３のGe19Sb38
Te43はスパッタ法により成膜した。下地層２の(ZnS)0.8
(SiO2)0.2および保護層４のAlNはスパッタ法により成膜
した。反射層５はスパッタ層により成膜した。 Hereinafter, a film is formed on a PC substrate according to Examples 14 and 15,
The results of measuring the optical characteristics will be described. Ge 19 Sb 38 of the recording layer 3
Te 43 was formed by a sputtering method. (ZnS) of underlayer 2 0.8
(SiO 2 ) 0.2 and AlN of the protective layer 4 were formed by sputtering. The reflection layer 5 was formed by a sputtering layer.
作成した試料の波長λ＝830nmに対する基板入射の反
射率Ｒ、透過率Ｔ、吸収率Ａを測定した結果を第８表に
示す。スパッタしたままの状態と結晶化した状態につい
て測定した。Table 8 shows the measurement results of the reflectance R, the transmittance T, and the absorptance A of the prepared sample at a wavelength of λ = 830 nm, which were incident on the substrate. The measurement was performed on the as-sputtered state and the crystallized state.
反射層５にSiを用いた他の例として、記録層３にGe2S
b2Te5を用いた場合について述べる。Ge2Sb2Te5は、スパ
ッタしたままの状態で屈折率4.15、消衰係数0.96、結晶
状態で屈折率5.64、消衰係数3.05であった。下地層２お
よび保護層４にはSi3N4を用いた。波長λ＝830nm、下地
層の屈折率ｎ＝2.0に対して、下地層の膜厚をλ/2nの5/
8に固定し、記録層３及び保護層４の膜厚を変化させて
基板入射の反射率、記録層３の吸収率を計算し、条件
（１）〜（４）をともに満たす領域を反射層がTiの場合
と同様にして求めた。（１）〜（４）をともに満たす領
域を第14図に示す。これらの領域から光学的に最適化さ
れた媒体構成の具体例を第９表に示す。 As another example using Si for the reflection layer 5, Ge 2 S
The case where b 2 Te 5 is used will be described. Ge 2 Sb 2 Te 5 had a refractive index of 4.15 and an extinction coefficient of 0.96 in the as-sputtered state, and a refractive index of 5.64 and an extinction coefficient of 3.05 in the crystalline state. Si 3 N 4 was used for the underlayer 2 and the protective layer 4. For a wavelength of λ = 830 nm and a refractive index of the underlying layer of n = 2.0, the thickness of the underlying layer is set to 5/5 of λ / 2n.
8 and the film thickness of the recording layer 3 and the protective layer 4 are changed to calculate the reflectance at the substrate incidence and the absorptance of the recording layer 3. The region satisfying all of the conditions (1) to (4) is defined as the reflective layer. Was determined in the same manner as in the case of Ti. FIG. 14 shows regions satisfying all of (1) to (4). Table 9 shows specific examples of media configurations that are optically optimized from these regions.
以下、実施例16、17に従ってPC基板上に成膜を行い、
光学特性を測定した結果を述べる。記録層３のGe2Sb2Te
5はスパッタ法により成膜した。下地層２および保護層
４のSi3N4は反応性スパッタ法により成膜した。反射層
５はスパッタ法により成膜した。 Hereinafter, a film is formed on a PC substrate according to Examples 16 and 17,
The results of measuring the optical characteristics will be described. Ge 2 Sb 2 Te of the recording layer 3
5 was formed by a sputtering method. Si 3 N 4 of the underlayer 2 and the protective layer 4 was formed by a reactive sputtering method. The reflection layer 5 was formed by a sputtering method.
作成した試料の波長λ＝830nに対する基板入射の反射
率Ｒ、透過率Ｔ、吸収率Ａを測定した結果を第10表に示
す。スパッタしたままの状態と結晶化した状態について
測定した。Table 10 shows the measurement results of the reflectance R, the transmittance T, and the absorptance A of the sample thus prepared at a wavelength of λ = 830 n when the substrate was incident. The measurement was performed on the as-sputtered state and the crystallized state.
（発明の効果） 以上説明したように、ガラス基板上に単層で形成した
場合の基板入射光に対する反射率が25％以上70％以下で
ある反射層を備えることにより、相変化 型ディスクにおいて、結晶化前後の反射率の変化を大き
くとり、かつ吸収率の変化の小さな媒体構成を選択でき
るようになり、記録点と消去点の吸収率の差を小さくで
きるため、重ね書きの能力を大幅に向上できる。(Effects of the Invention) As described above, when a single layer is formed on a glass substrate, the reflective layer having a reflectance of 25% or more and 70% or less with respect to the light incident on the substrate is provided, whereby the phase change is achieved. In the type disk, it is possible to select a medium configuration in which the change in reflectance before and after crystallization is large and the change in absorption is small, and the difference between the absorption at the recording point and the erasure point can be reduced. The ability can be greatly improved.
【図面の簡単な説明】 第１図は本発明による相変化型光ディスクの基本構成の
断面図、第２図〜第27図は、本発明の作用を示す図であ
る。 １…基板、２…下地層、３…記録層、４…保護層、５…
反射層BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of the basic structure of a phase-change optical disk according to the present invention, and FIGS. 2 to 27 are views showing the operation of the present invention. DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Underlayer, 3 ... Recording layer, 4 ... Protective layer, 5 ...
Reflective layer
フロントページの続き (56)参考文献 特開 昭62−139149（ＪＰ，Ａ) 特開 昭63−9040（ＪＰ，Ａ) 特開 平２−54442（ＪＰ，Ａ) 特開 平３−71441（ＪＰ，Ａ) 特開 平１−149238（ＪＰ，Ａ) 特開 平２−128330（ＪＰ，Ａ) 特開 平２−57387（ＪＰ，Ａ) 特開 昭63−298729（ＪＰ，Ａ) 特開 平２−113451（ＪＰ，Ａ)Continuation of front page (56) References JP-A-62-139149 (JP, A) JP-A-63-9040 (JP, A) JP-A-2-54442 (JP, A) JP-A-3-71441 (JP) JP-A-1-149238 (JP, A) JP-A-2-128330 (JP, A) JP-A-2-57387 (JP, A) JP-A-63-298729 (JP, A) 2-113451 (JP, A)
Claims (1)
る昇温、冷却の熱履歴の違いにより光学的性質の変化す
る記録層と、保護層と、反射層とを順次備えた光学的情
報記録媒体において、前記記録層が成膜したままの状態
での前記光学的情報記録媒体の基板側から入射したとき
の反射率が５％以上であり、前記記録層を成膜したまま
の状態から結晶化させた時の前記光学的情報記録媒体の
基板側から入射したときの反射率の変化が15％以上であ
り、前記記録層を成膜したままの状態と前記記録層が結
晶化した状態における前記光学的情報記録媒体の前記記
録層の吸収率が60％以上であり、前記記録層を成膜した
ままの状態から結晶化させた時の前記光学的情報記録媒
体の前記記録層の吸収率の変化が５％以下であり、前記
反射層がSiであり、前記Siによる前記反射層がガラス基
板上に単層で形成された場合に基板側から入射した光に
対する反射率が25％以上70％以下であることを特徴とす
る光学的情報記録媒体。1. An optical system comprising: a base layer; a recording layer whose optical properties change due to a difference in heat history of temperature rise and cooling by laser beam irradiation; a protective layer; The optical information recording medium has a reflectance of 5% or more when incident from the substrate side of the optical information recording medium in a state where the recording layer is formed, and the recording layer is formed as it is. The change in reflectance when incident from the substrate side of the optical information recording medium when crystallized from the state is 15% or more, and the state in which the recording layer is formed and the state in which the recording layer is crystallized The recording layer of the optical information recording medium has an absorptance of 60% or more in a state where the recording layer is formed, and the recording layer of the optical information recording medium when the recording layer is crystallized from an as-deposited state. The change in absorptance of 5% or less, the reflective layer is Si, The optical information recording medium reflectivity for light incident from the substrate side when the reflective layer by serial Si are formed in a single layer on a glass substrate is equal to or less than 70% to 25%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21883490A JP3180813B2 (en) | 1990-08-20 | 1990-08-20 | Optical information recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21883490A JP3180813B2 (en) | 1990-08-20 | 1990-08-20 | Optical information recording medium |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04102243A JPH04102243A (en) | 1992-04-03 |
| JP3180813B2 true JP3180813B2 (en) | 2001-06-25 |
Family
ID=16726074
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21883490A Expired - Fee Related JP3180813B2 (en) | 1990-08-20 | 1990-08-20 | Optical information recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3180813B2 (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0566107B1 (en) * | 1992-04-17 | 1998-03-18 | Matsushita Electric Industrial Co., Ltd. | Optical information recording medium and method of designing its structure |
| JP2737666B2 (en) * | 1994-10-18 | 1998-04-08 | 日本電気株式会社 | Optical information recording medium |
| JP2806274B2 (en) * | 1994-10-19 | 1998-09-30 | 日本電気株式会社 | Optical information recording medium |
| JPH08287515A (en) * | 1995-02-13 | 1996-11-01 | Matsushita Electric Ind Co Ltd | Optical information recording medium |
| US6821707B2 (en) | 1996-03-11 | 2004-11-23 | Matsushita Electric Industrial Co., Ltd. | Optical information recording medium, producing method thereof and method of recording/erasing/reproducing information |
| JP3138661B2 (en) * | 1996-10-24 | 2001-02-26 | 日本電気株式会社 | Phase change optical disk |
| US6503690B1 (en) | 1997-08-12 | 2003-01-07 | Matsushita Electric Industrial Co., Ltd. | Optical information recording medium, method for producing the same, and method for recording and reproducing optical information |
| JPH11134720A (en) | 1997-08-28 | 1999-05-21 | Matsushita Electric Ind Co Ltd | Optical information recording medium and its recording/ reproducing method |
| US6343062B1 (en) | 1997-09-26 | 2002-01-29 | Matsushita Electric Industrial Co., Ltd | Optical disk device and optical disk for recording and reproducing high-density signals |
| TW448443B (en) | 1998-08-05 | 2001-08-01 | Matsushita Electric Ind Co Ltd | Optical information storage media and production method as well as the storage reproducing method and device |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62139149A (en) * | 1985-12-11 | 1987-06-22 | Matsushita Electric Ind Co Ltd | Optical information recording and reproducing disk |
| JPH0746442B2 (en) * | 1986-06-30 | 1995-05-17 | 松下電器産業株式会社 | Optical information recording medium |
| JP2532600B2 (en) * | 1988-08-19 | 1996-09-11 | 松下電器産業株式会社 | Information carrier disc |
| JPH0371441A (en) * | 1989-08-11 | 1991-03-27 | Asahi Chem Ind Co Ltd | Optical recording medium |
-
1990
- 1990-08-20 JP JP21883490A patent/JP3180813B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04102243A (en) | 1992-04-03 |
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