JPH0540964A - 光学的記録媒体 - Google Patents

光学的記録媒体

Info

Publication number
JPH0540964A
JPH0540964A JP3196621A JP19662191A JPH0540964A JP H0540964 A JPH0540964 A JP H0540964A JP 3196621 A JP3196621 A JP 3196621A JP 19662191 A JP19662191 A JP 19662191A JP H0540964 A JPH0540964 A JP H0540964A
Authority
JP
Japan
Prior art keywords
film
pit
recording medium
optical 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.)
Pending
Application number
JP3196621A
Other languages
English (en)
Inventor
Hiroshi Komata
宏志 小俣
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Canon Inc
Original Assignee
Canon Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Canon Inc filed Critical Canon Inc
Priority to JP3196621A priority Critical patent/JPH0540964A/ja
Priority to US07/922,777 priority patent/US5398232A/en
Publication of JPH0540964A publication Critical patent/JPH0540964A/ja
Pending legal-status Critical Current

Links

Classifications

    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B11/00Recording 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
    • G11B11/10Recording 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
    • G11B11/105Recording 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
    • G11B11/10582Record carriers characterised by the selection of the material or by the structure or form
    • G11B11/10584Record carriers characterised by the selection of the material or by the structure or form characterised by the form, e.g. comprising mechanical protection elements
    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B11/00Recording 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
    • G11B11/10Recording 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
    • G11B11/105Recording 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
    • G11B11/1055Disposition or mounting of transducers relative to record carriers
    • G11B11/10576Disposition or mounting of transducers relative to record carriers with provision for moving the transducers for maintaining alignment or spacing relative to the carrier
    • G11B11/10578Servo format, e.g. prepits, guide tracks, pilot signals
    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/2407Tracks or pits; Shape, structure or physical properties thereof
    • G11B7/24085Pits
    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/241Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
    • G11B7/252Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers
    • G11B7/257Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of layers having properties involved in recording or reproduction, e.g. optical interference layers or sensitising layers or dielectric layers, which are protecting the recording layers
    • G11B7/2578Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of layers having properties involved in recording or reproduction, e.g. optical interference layers or sensitising layers or dielectric layers, which are protecting the recording layers consisting essentially of inorganic materials
    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/241Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
    • G11B7/242Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers
    • G11B7/243Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising inorganic materials only, e.g. ablative layers
    • G11B2007/24302Metals or metalloids
    • G11B2007/24306Metals or metalloids transition metal elements of groups 3-10
    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/241Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
    • G11B7/252Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers
    • G11B7/257Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of layers having properties involved in recording or reproduction, e.g. optical interference layers or sensitising layers or dielectric layers, which are protecting the recording layers
    • G11B2007/25705Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of layers having properties involved in recording or reproduction, e.g. optical interference layers or sensitising layers or dielectric layers, which are protecting the recording layers consisting essentially of inorganic materials
    • G11B2007/2571Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of layers having properties involved in recording or reproduction, e.g. optical interference layers or sensitising layers or dielectric layers, which are protecting the recording layers consisting essentially of inorganic materials containing group 14 elements except carbon (Si, Ge, Sn, Pb)
    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/241Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
    • G11B7/252Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers
    • G11B7/257Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of layers having properties involved in recording or reproduction, e.g. optical interference layers or sensitising layers or dielectric layers, which are protecting the recording layers
    • G11B2007/25705Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of layers having properties involved in recording or reproduction, e.g. optical interference layers or sensitising layers or dielectric layers, which are protecting the recording layers consisting essentially of inorganic materials
    • G11B2007/25713Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of layers having properties involved in recording or reproduction, e.g. optical interference layers or sensitising layers or dielectric layers, which are protecting the recording layers consisting essentially of inorganic materials containing nitrogen
    • GPHYSICS
    • G11INFORMATION STORAGE
    • G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B7/00Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
    • G11B7/24Record carriers characterised by shape, structure or physical properties, or by the selection of the material
    • G11B7/241Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
    • G11B7/252Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers
    • G11B7/253Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates
    • G11B7/2533Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates comprising resins
    • G11B7/2534Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates comprising resins polycarbonates [PC]

Landscapes

  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Optical Record Carriers And Manufacture Thereof (AREA)
  • Optical Recording Or Reproduction (AREA)

Abstract

(57)【要約】 【目的】 光学的記録媒体の記録密度を高くするために
プリピット間隔をつめても信号出力が低下しないように
する。 【構成】 基板1上には基板1の屈折率よりも大きな屈
折率を有する反射防止膜2が設けられている。ここで、
ランド部4の反射防止膜2の膜厚6はプリピット底部5
の反射防止膜2の膜厚7より厚くなっている。したがっ
て、この場合、プリピット底部5の反射率がランド部4
の反射率より高くなる。

Description

【発明の詳細な説明】
【0001】
【産業上の利用分野】本発明は、光ビームを用いて情報
の記録再生、消去が行なわれる光学的記録媒体に関す
る。
【0002】
【従来の技術】従来、光学的記録媒体には光学的案内溝
(以下、グルーブと記す)にはさまれたランドと呼ばれ
る部分に、アドレスデータを記録したプリピットと呼ば
れる深さλ/4n(λ:読み取り光の波長、n;基板の
屈折率)の凹部が形成されている。このプリピットの有
無によって明暗が作られ、これがアドレスデータとな
る。
【0003】
【発明が解決しようとする課題】しかしながら、上記の
従来例の光学的記録媒体では、記録密度を高くするため
にプリピット長を短くしたりプリピット間隔をつめてい
くと、読み取り光のスポット径が一定であれば信号出力
(明暗差)は低下していくという欠点があった。これは
プリピットとプリピットの中間に読み取り光のスポット
が入った時に、前後のプリピットの影響を受け十分な反
射光量が得られないためである。そこでプリピットのサ
イズを小さくして、その部分の影響を減少させると、プ
リピット上に読み取り光のスポットがある時に暗くなら
ないため、結局信号出力は向上しない。つまり、ピット
形状を変更しても、読み取り光のスポットが一定の場
合、アドレスデータの記録密度を高くすると、ピット間
隔がつまった部分で十分な信号出力が得られない。
【0004】本発明の目的は、記録密度を高くするため
にプリピット間隔をつめても信号出力(明暗差)が低下
することがない光学的記録媒体を提供することである。
【0005】
【課題を解決するための手段】本発明の光学的記録媒体
は、プリピット底部の反射率がランド部の反射率より高
い。
【0006】
【作用】一般に、光学的記録媒体では反射率を調整する
ために基板表面に基板より大きい屈折率の反射防止膜を
設ける。この反射防止膜の屈折率と膜厚を適当に選択す
れば図4にあるように目的とする反射率を得ることがで
きる。当然屈折率が同じでも膜厚が異なれば反射率は変
化する。そこで本発明によればプリピット底部とランド
部における反射防止膜の膜厚を変えることでプリピット
底部の反射率をランド部の反射率より高くすることが可
能となり、これによりプリピットのピットサイズが小さ
くてもプリピット上に読み取り光のスポットがある時に
十分に暗くなるため、プリピットとプリピットの中間に
読み取り光のスポットが入った時の反射光量をピットサ
イズを小さくすることで増加させることができ、記録密
度を高くするためにプリピット間隔をつめても信号出力
が低下することがない。
【0007】
【実施例】次に、本発明の実施例について図面を参照し
て説明する。
【0008】図1は本発明の第1の実施例の光学的記録
媒体の断面図である。なお、同図では煩雑を避けるため
ハッチングは施されていない。
【0009】本実施例の光学的記録媒体は、基板1と、
記録層3と、基板1と記録層3の間に設けられた反射防
止膜2からなっている。ここで、ランド部4の反射防止
膜膜厚6はプリピット底部5の反射防止膜膜厚7より厚
くされている。図4を見てわかるように各屈折率におい
て反射防止膜の膜厚を厚くしていくと反射率が低下して
いく領域と逆に反射率が増加していく領域がある膜厚を
境にして存在する。本実施例においては前者の領域にお
ける効果を利用している。既に述べた様にプリピット底
部5における反射防止膜膜厚7はランド部4の反射防止
膜膜厚6より薄いため図4のグラフに従ってプリピット
底部5の反射率がランド部4の反射率より高くなる。つ
まり、通常よりプリピット底部5の反射光量9は多くな
る。換言すれば通常より小さいピットで同じ効果を達成
できる。これを示したのが図3のプリピットサイズと反
射光量および信号出力のグラフである。前述の理由で本
実施例のプリピットの真上に読み取り光のスポットがあ
る時の反射光量13は従来のもの12に比べプリピット
サイズが小さい側にシフトする。さらに、プリピットと
プリピットの間に読み取り光のスポットがある時は従来
のもの14と本実施例のもの15で12,13との差ほ
ど変化しないためプリピットの真上とプリピット間との
明暗差である信号出力は本実施例のもの11が、従来の
もの10より大きくなる。この様な反射防止膜2を設け
る手段の1つとして、高周波または直流スパッタ法を用
いて窒化シリコン等の誘電体膜を基板1上に設ける際に
プラズマに対する基板のシース電圧(一側)を大きく設
定することにより基板1の平坦部(ランド部4)に比べ
凹部(プリピット部)における膜のつきまわりを悪くす
る方法がある。
【0010】図2は本発明の第2の実施例の光学的記録
媒体の断面図である。本図においても煩雑を避けるため
にハッチングは施されていない。
【0011】本実施例は第1の実施例とは逆に反射防止
膜の膜の膜厚が厚くなるにつれて反射率が高くなる領域
における効果を利用するため、プリピット底部5の反射
防止膜2’の膜厚6’はランド部4の反射防止膜2’の
膜厚7’に比べ厚くされている。これにより第1の実施
例で説明したのと同様の信号出力の向上が得られる。こ
の様な反射防止膜2’を設ける手段の1つとして、高周
波または直流スパッタ法を用いて窒化シリコン等の誘電
体膜を基板1上に設ける際にプラズマに対する基板1の
シース電圧(一側)を小さく設定することにより基板平
坦部(ランド部4)に比べ凹部(プリピット部)におけ
る膜のつきまわりを良くする方法がある。
【0012】
【発明の効果】以上説明したように本発明は、プリピッ
ト底部の反射率をランド部より高くすることにより、プ
リピット間隔をつめてもプリピット間隔のつまった部分
での出力信号が低下しないという効果がある。
【図面の簡単な説明】
【図1】本発明の第1の実施例の光学的記録媒体の断面
図である。
【図2】本発明の第2の実施例の光学的記録媒体の断面
図である。
【図3】本実施例の効果を示すグラフである。
【図4】反射防止膜の膜厚に対する反射率の変化を示す
グラフである。
【符号の説明】
1 基板 2,2’ 反射防止膜 3 記録層 4,4’ ランド部 5,5’ プリピット底部 6,6’ ランド部4の反射防止膜2,2’の膜厚 7,7’ プリピット底部5の反射防止膜2,2’の
膜厚 8,8’ ランド部4の反射光量 9,9’ プリピット底部5の反射光量 10 従来例のプリピット信号出力 11 本実施例のプリピット信号出力 12 プリピットの真上に読み取り光のスポットがあ
る時の反射光量(従来例) 13 プリピットの真上に読み取り光のスポットがあ
る時の反射光量(実施例) 14 プリピットとプリピットの間に読み取り光のス
ポットがある時の反射光量(従来例) 15 プリピットとプリピットの間に読み取り光のス
ポットがある時の反射光量(実施例)

Claims (3)

    【特許請求の範囲】
  1. 【請求項1】 グルーブと呼ばれる光学的案内溝と、該
    グルーブにはさまれたランド部分にアドレスデータ等が
    記録してあるプリピットを有する光学的記録媒体におい
    て、 前記プリピットの底部の反射率が前記ランド部の反射率
    より高いことを特徴とする光学的記録媒体。
  2. 【請求項2】 基板の屈折率より大きな屈折率を有する
    反射防止膜を該基板上に有し、前記反射防止膜の膜厚が
    厚くなるにつれて反射率が低くなる場合前記プリピット
    底部における前記反射防止膜の膜厚が前記ランド部にお
    ける前記反射膜の膜厚よりも薄い請求項1記載の光学的
    記録媒体。
  3. 【請求項3】 基板の屈折率より大きな屈折率を有する
    反射防止膜を該基板上に有し、前記反射防止膜の膜厚が
    厚くなるにつれて反射率が高くなる場合前記プリピット
    底部における前記反射防止膜の膜厚が前記ランド部にお
    ける前記反射膜の膜厚よりも厚い請求項1記載の光学的
    記録媒体。
JP3196621A 1991-08-06 1991-08-06 光学的記録媒体 Pending JPH0540964A (ja)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP3196621A JPH0540964A (ja) 1991-08-06 1991-08-06 光学的記録媒体
US07/922,777 US5398232A (en) 1991-08-06 1992-07-31 Optical recording medium with prepit areas having reflectivity higher than land areas

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP3196621A JPH0540964A (ja) 1991-08-06 1991-08-06 光学的記録媒体

Publications (1)

Publication Number Publication Date
JPH0540964A true JPH0540964A (ja) 1993-02-19

Family

ID=16360803

Family Applications (1)

Application Number Title Priority Date Filing Date
JP3196621A Pending JPH0540964A (ja) 1991-08-06 1991-08-06 光学的記録媒体

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JP3496301B2 (ja) * 1994-11-29 2004-02-09 ソニー株式会社 光ディスク基板及び光ディスク
JPH10106040A (ja) * 1996-09-26 1998-04-24 Canon Inc 光学的情報記録媒体および光学的情報記録再生装置
US5844876A (en) * 1996-09-26 1998-12-01 Victor Company Of Japan, Ltd. Double-layer optical disk, recording method and manufacturing method of this optical disk

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JPS59113534A (ja) * 1982-12-20 1984-06-30 Canon Inc 光学記録媒体
US4777068A (en) * 1984-08-10 1988-10-11 Canon Kabushiki Kaisha Optical recording medium
JPS61104346A (ja) * 1984-10-23 1986-05-22 Canon Inc 光磁気記録媒体
US5059510A (en) * 1985-02-04 1991-10-22 Hoechst Celanese Corp. Media for optical information storage comprising an organic macrocyclic chromophore substituted with a film conferring organic substituent
US5144552A (en) * 1986-07-25 1992-09-01 Ricoh Company, Ltd. Optical information storage medium having grooves and pits with specific depths, respectively
US4841515A (en) * 1987-07-01 1989-06-20 Micronic Interface Technologies Read-write optical disk
JPS6472342A (en) * 1987-09-14 1989-03-17 Canon Kk Optical recording medium
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US5274623A (en) * 1990-07-19 1993-12-28 Fuji Photo Film Co., Ltd. Information recording medium having high modulation degree

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