JP3983944B2 - Method for producing optical information recording medium - Google Patents
Method for producing optical information recording medium Download PDFInfo
- Publication number
- JP3983944B2 JP3983944B2 JP28490499A JP28490499A JP3983944B2 JP 3983944 B2 JP3983944 B2 JP 3983944B2 JP 28490499 A JP28490499 A JP 28490499A JP 28490499 A JP28490499 A JP 28490499A JP 3983944 B2 JP3983944 B2 JP 3983944B2
- Authority
- JP
- Japan
- Prior art keywords
- recording
- puh
- reproduction
- optical information
- jitter
- 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 - Fee Related
Links
Images
Landscapes
- Optical Head (AREA)
- Optical Record Carriers And Manufacture Thereof (AREA)
- Optical Recording Or Reproduction (AREA)
- Manufacturing Optical Record Carriers (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は光情報記録媒体、特にレーザ光によって記録可能な光情報記録媒体の作製方法に関する。
【０００２】
【従来の技術】
有機材料を用いた光情報記録媒体は、複素屈折率の波長依存性が大きいため、波長が異なると反射率、変調度やトラッキング信号等、さらにはジッタも大きく異なる。したがって、記録ＰＵＨ（ＰＵＨ：ピックアップヘッド）で最適な記録を行っても、再生ＰＵＨで再生すると、ジッタは劣悪で、規格値から大きくはずれるという場合が生じる。
また逆に再生ＰＵＨ（ＰＵＨ：ピックアップヘッド）で最適な記録領域でも、記録ＰＵＨで再生すると、ジッタは劣悪であるという場合が生じていた。
このように波長によってジッタが大きく変化してしまう光情報記録媒体の場合、現状では、記録時はＯＰＣによって記録波長で最適となるように記録されるため、再生波長でのジッタは保障されず、記録時のＯＰＣも無意味なものとなってしまう恐れがある。例えば、非環状化合物（例えばアゾ金属錯体化合物）を記録層材料とする光情報記録媒体の場合（４．７ＧＢ ＤＶＤ−Ｒ）、膜厚や基板溝条件等によって、図１に示すように最適記録条件が記録ＰＵＨ（６３５ｎｍ）と再生ＰＵＨ（６５０ｎｍ）で大きく異なる場合が生じる（図１において、略円形の曲線はジッタ値を等高線で表したものであり、略円が小さいほどジッタ値が小さい）。すなわち、図１において、記録ＰＵＨでの再生では、マルチパルス長が０．６６（Ｔ）、記録パワーを１０．８（ｍＷ）として記録した記録部近傍が最適ジッタを示すのに対し、再生ＰＵＨでの再生ではマルチパルス長が０．７１（Ｔ）で、記録パワーを１１．１（ｍＷ）として記録した記録部近傍が最適ジッタを示す。
ただし、図１は ＤＶＤ Ｓｐｅｃｉｆｉｃａｔｉｏｎｓ ｆｏｒ Ｒｅｃｏｒｄａｂｌｅ Ｄｉｓｋ （ＤＶＤ−Ｒ） Ｐａｒｔ１ ＰＨＹＳＩＣＡＬ ＳＰＥＣＩＦＩＣＡＴＩＯＮＳ Ｖｅｒｓｉｏｎ １．０ Ｊｕｌｙ １９９７に記載の記録ストラテジのうち、マルチパルス長と記録パワーを変化させて各条件で記録し、記録ＰＵＨでの再生と再生ＰＵＨでの再生によるＤａｔａ ｔｏ Ｃｌｏｃｋジッタを各記録条件部で測定したものである。
【０００３】
また、記録ＰＵＨと再生ＰＵＨが規格上同一の光情報記録媒体であっても、レーザの個体差や環境温度、レーザ強度等によって発振波長はある有限の波長域を有することになるため、ジッタの波長依存性の大小はあるが、上述の記録ＰＵＨと再生ＰＵＨで波長が異なる場合と同様に波長バラツキによってジッタに差が生じる可能性があるため、記録装置、および再生装置間の再生互換性が十分保たれないとう危険性がある。
さらに、記録ＰＵＨと再生ＰＵＨ（再生のみ可能な装置）では一般的にリムインテンシティが異なるため、ビ−ム径に違いが生じ、記録装置、および再生装置間の再生互換性が十分保たれないとう危険性がある。
【０００４】
【発明が解決しようとする課題】
本発明は、有機材料を用いた光情報記録媒体の作製方法において、再生互換性が高く、信頼性の非常に高い光情報記録媒体の作製方法を提供することを目的とする。
すなわち、再生波長の違いや波長バラツキ、およびビ−ム径の大小等によって、再生信号の見え方が異なることを防止して、どの装置を用いても良好なジッタが得られる光情報記録媒体の作製方法を提供することを目的とし、特にＤＶＤ−Ｒの規格に基づく光情報記録媒体にあっては、記録ＰＵＨ、再生ＰＵＨのどちらで再生しても、ジッタ特性が略等しい光情報記録媒体の作製方法を提供することを目的とする。
【０００５】
【課題を解決するための手段】
前記課題は光情報記録媒体の記録層膜厚の最適化を図る次の発明によって解決することができた。
すなわち、本発明の第１は、記録層が主として非環状化合物から構成された光情報記録媒体であって、第１レーザにより記録および再生を行うと共に前記第１レーザの記録パワーを複数段階で可変な記録ＰＵＨを用いて、作製後に、前記記録層に記録が為されると共に、第２レーザにより再生のみを行う再生ＰＵＨを用いて再生が為される光情報記録媒体の作製方法において、
前記記録層の膜厚が異なる複数種のそれぞれに対して、前記記録ＰＵＨを用いて複数段階の記録パワーで記録を行い、前記記録ＰＵＨを用いて再生が為されたときのジッタが最小となるように記録が為される最適記録パワーＰｗを、前記膜厚が異なる複数種毎に求める工程と、
前記記録層の膜厚が異なる複数種のそれぞれに対して、前記記録ＰＵＨを用いて複数段階の記録パワーで記録を行い、前記再生ＰＵＨを用いて再生が為されたときのジッタが最小となるように記録が為される最適記録パワーＰｒを、前記膜厚が異なる複数種毎に求める工程と、
前記膜厚が異なる複数種毎に求めた複数の前記最適記録パワーＰｗおよび前記膜厚が異なる複数種毎に求めた複数の前記最適記録パワーＰｒに基づいて、前記最適記録パワーＰｗと前記最適記録パワーＰｒとの差が最小となる前記膜厚を求める工程と、
求めた前記差が最小となる膜厚となるように、前記記録層を形成する工程と、
を備えたことを特徴とする光情報記録媒体の作製方法である。
【０００６】
本発明の第２は、前記最適記録パワーＰｗを求める工程は、前記膜厚毎に用意した、前記各段階の記録パワーにより記録が為された複数の前記光情報記録媒体それぞれに対して、前記記録ＰＵＨにより再生が為されたときのジッタを求め、求めた複数のジッタのうち最小のジッタに対応する前記記録パワーを、当該膜厚における前記最適記録パワーＰｗとすることで行われることを特徴とする請求項１に記載の光情報記録媒体の作製方法である。
本発明の第３は、前記最適記録パワーＰｒを求める工程は、前記膜厚毎に用意した、前記各段階の記録パワーにより記録が為された複数の前記光情報記録媒体それぞれに対して、前記再生ＰＵＨにより再生が為されたときのジッタを求め、求めた複数のジッタのうち最小のジッタに対応する前記記録パワーを、当該膜厚における前記最適記録パワーＰｒとすることで行われることを特徴とする請求項１又は２に記載の光情報記録媒体の作製方法である。
【０００７】
以下、本発明を詳細に説明する。
本発明者は前記課題を解決するために鋭意検討の結果、前述のように記録ＰＵＨと再生ＰＵＨでジッタ特性が大きく異なる理由は、再生ビ−ム径の違いと有機材料の大きな波長依存性のほかに、記録マークの位相形成のメカニズムにあることを見出し、本発明に到達することができた。
すなわち、ジッタが再生するＰＵＨの波長で大きく異なる原因が、再生するＰＵＨの波長によってアシンメトリが異なることにあり、これは再生レーザ光と記録レーザ光のビーム径が異なり、かつ記録材料の基板内部への拡散性が高い場合に顕著に現れることがわかった（記録層材料の屈折率の波長依存性による寄与は少ない）。
【０００８】
再生レーザ光と記録レーザ光のビーム径が異なる場合は、まず第一に記録波長と再生波長が異なる場合やＮＡが異なる場合等が考えられるが、本発明ではこれらの場合に限らず、記録波長と再生波長が規格上同一である光情報記録媒体にも適用される。すなわち、半導体レーザの波長は製造バラツキや、環境温度、記録再生パワーによって大きく変動する可能性があるため、たとえ規格上で記録波長と再生波長が同一であっても同一のビ−ム形状となる保証はない。また通常、記録ビーム径は記録材料を分解させるために高出力が得られるように整形したり、再生ビーム径はＲＯＭが最も良好に再生できるように整形する必要があるためリムインテンシティが異なり、記録ビーム形状と再生ビーム形状は異なる場合が一般的であり、また再生装置間での波長バラツキ、ビーム径のバラツキも０ではないからである。
したがって、本発明における膜厚の最適化を行うにあたって、記録波長と再生波長が異なる場合は、両者の代表的な装置で記録層膜厚の最適化を行えば十分であり、一方記録波長と再生波長が同一である場合は、考えられる範囲内で波長ずれ、あるいはビーム形状の異なる装置を用いて（一般的には記録ＰＵＨと再生専用ＰＵＨ間での整合を図ればよい）、記録層膜厚の最適化を行えばよい。
例えばＤＶＤ Ｓｐｅｃｉｆｉｃａｔｉｏｎｓ ｆｏｒ Ｒｅｃｏｒｄａｂｌｅ Ｄｉｓｋ （ＤＶＤ−Ｒ） Ｐａｒｔ１ ＰＨＹＳＩＣＡＬ ＳＰＥＣＩＦＩＣＡＴＩＯＮＳ Ｖｅｒｓｉｏｎ １．０ Ｊｕｌｙ １９９７では再生波長に関し１０（ｎｍ）の波長分布を許容する旨の記載があるが、環境温度や再生パワー等による波長変動を含めると、実際には更に大きな波長分布を有することになる。したがって、規格上記録波長と再生波長が同一である場合でも上記波長バラツキによるビ−ム径の差と、リムインテンシティの違いによるビ−ム径の差が加わるため、記録ＰＵＨと再生ＰＵＨでの再生特性は大きく異なる可能性がある。
これは、実際各メーカーのＤＶＤプレーヤーや評価装置を用いて同一のメディアを評価しても、ジッタ値の絶対値が小さい範囲内で変動するだけでなく、ジッタ値が大きく異なる場合や、異なる記録条件部を再生した場合にはジッタの記録条件依存性が全く異なる場合が頻繁に生じることからも容易に推測できる。
【０００９】
ジッタが再生するＰＵＨで大きく異なる原因は、上述の再生時のＰＵＨの波長の違い（基本的にはビーム径が重要。波長が異なるとビーム径も一般的に変わると考える）やリムインテンシティの違いによってビーム径が異なることに一因があるが、記録材料の基板内部への拡散性が小さい場合は、ジッタの波長依存性は少なくすることができる。
すなわち、再生時のＰＵＨのビーム径が装置間で異なるシステムにおいて（記録ＰＵＨと再生ＰＵＨでの再生ビ−ム径は異なる。また再生ＰＵＨ間でも通常はある範囲内で異なるはずである）、拡散性が高い記録材料、または拡散性の高いディスク構成を用いた場合に、ジッタの再生ＰＵＨ依存性が大きくなるのである。
【００１０】
以下記録材料の拡散性について説明する。
ここでいう、拡散性とは記録層材料の分解物が膨張した基板内へ拡散する現象のことを指し、拡散性を考慮した場合の光学位相差を数式で示すと次のようになる。すなわち、図２に示すように記録によって、基板にバンプが形成され、同時に反射層と記録層界面にピットが形成されるとし、記録層の記録による屈折率変化を記録層内で平均化し、その屈折率を（ｎｄ−δｎｄ）とすると、光学位相は以下のように表される。
【００１１】
【数１】
▲１▼：バンプ形成（基板と記録層界面）
▲２▼：ピット形成（基板と反射層界面）
▲３▼：基板屈折率低下分（バンプ形成による）
▲４▼：記録層屈折率低下分（分解による）
【００１２】
すなわち、拡散が生じない記録材料の場合は、▲１▼▲２▼▲３▼▲４▼の全ての項による位相差が加算されるが、拡散が生じる記録材料の場合は、拡散によって体積膨張によって屈折率が低下した基板中（バンプが形成された部分）に、記録層材料の分解物が拡散するため、基板屈折率の低下分がキャンセルされ、また記録層の屈折率も記録層材料の分解物が基板内へ拡散してしまうため，その低下分が少なくなる。すなわち、拡散が生じる記録材料の場合は、数１の▲１▼▲２▼によって光学位相差が生じる（▲３▼▲４▼の寄与は少ない）。このことから、拡散が生じる記録材料の変調度は、拡散が生じない記録材料よりも小さくなることがわかる。
なお、ここでは記録によって基板内へは記録層材料の分解物のみが拡散するような記述をしたが、実際は基板溶融や記録材料の溶融によって、特に記録マークの前後左右のエッジ近傍では記録層材料の分解物とともに未分解物や副生成物も基板内へ拡散する。しかし、記録層材料の未分解物や副生成物は、一般に分子が大きくまた電子的な相互作用力を保持しているため、必ずしも基板材料と分子レベルで相溶しないと考えられるので、基板の体積膨張による屈折率低下を補償する能力は、分解物に比べ低いと考える。
【００１３】
この拡散という現象の存在は、実際に記録部の光学位相差を見積もることで証明できる。例えば、次の値を用いて光学位相差を計算する（参考：Ｊｐｎ．Ｊ．Ａｐｐｌ．Ｐｈｙｓ．Ｖｏｌ．３１（１９９２）Ｐｔ．１，Ｎｏ．２Ｂ ｐｐ４８４−４９３）。
・基板の屈折率ｎｓ＝１．５７、記録層の屈折率をｎｄ＝２．７０
・バンプの高さ ｄＢ＝６０（ｎｍ）、
ピットの深さ ｄＰ＝７（ｎｍ）：ＳＥＭ等による観察
・分解によって色素の屈折率が１．５に変化
・分解相当膜厚を７０（ｎｍ）：記録部の光学特性の変化を膜厚値に換算
・バンプによって約２０％ｄＢが増加：Ｃｌａｕｓｉｕｓ Ｍｏｓｓｏｔｉｅｑｕａｔｉｏｎから
【数２】
また、屈折率低下領域を３００（ｎｍ）とする。
∴δＯＰＤ’＝１３６＋３８＋６６＋１６８＝４０８（ｎｍ）≫λ／２＝６３５／２となり、変調度は
【数３】
【００１４】
このように有機材料を用いた追記型光情報記録媒体の場合、拡散性を考慮する必要があるが、この拡散性の大小は記録層材料自身の拡散のしやすさ、および基板溝形状に依存すると考えられる。
例えば、テトラアザポルフィリン誘導体などの大環状化合物は基本骨格が頑丈であり、分解時に分解するユニット数が少なく、また分解物ユニットが大きい（記録によって置換基の結合が切れ、この比較的小さな分解物が主に基板内へ拡散する）。一方、アゾ金属錯体等の非環状化合物では、分解時に分解するユニット数が多く、また各分解物ユニットは比較的小さい。
したがって、テトラアザポルフィリン誘導体等の環状化合物は低拡散性を示し、アゾ金属錯体等の非環状化合物は高拡散性を示しやすい。
【００１５】
また、拡散は記録層のうち、基板と接触する部分が最も起こりやすいと考えられるから、基板の溝形状（幅や深さ）によって拡散効果の見え方の大小が変化する。記録による位相差は主に記録層材料の分解による屈折率変化によって生じており、拡散効果はこの屈折率変化による位相差発生を抑制する方向に働き、この両者の略加算で実際の位相差が発生している。
【００１６】
拡散性が高い記録材料からなる光情報記録媒体を、異なる波長、すなわち異なるビーム形状で再生する場合を考える。
再生ビーム形状に対して、３Ｔ、４Ｔ等の短い記録マークは、例えばビーム前方が記録部の後方にさしかかった時、ビーム内にはマーク全体が収まっている状況になるため、短マーク内の位相の位置分布を分離して再生することはできず（分解能がない）、短マーク全体の平均値的な信号しか得られない。
そのため短マークでは、マークの後方熱蓄積効果があるにもかかわらず、マーク後方の変調度が前方に対して増加することなく、ビームの走査方向に対する位相分布が対称となって見える。
一方、再生ビ−ム径に対して、１１Ｔ、１４Ｔ等の長い記録マークは、例えばビーム前方が記録部の後方にさしかかった時、ビーム内にはマーク全体が収まっていない状況になるため、長マーク内の位相の位置分布をある範囲内で分離して再生することができるようになるため（分解能がある）、再生位置にあわせた信号が得られる。そのため長マークでは、マークの後方熱蓄積効果によって、マーク後方の変調度が前方に対して増加するマークが観測され、ビームの走査方向に対する位相分布が非対称となって見える。このように長マークでは記録マーク内の位相分布がある程度の分解能をもって検出されるから、記録マーク内の拡散性による変調度の低下も検出されてしまう。
【００１７】
記録マークは、主に記録層材料の分解による屈折率変化による位相増加成分と拡散性による変調度減少成分の足しあわせで成り立っている。
記録層材料の分解による変調度増加寄与は後方熱蓄積効果によって、マーク後方で増大し、一方、拡散性による変調度の減少寄与は、屈折率変化に寄与する記録層領域に対して、拡散に寄与する記録層領域は小さいため、マーク後方に向かって変調度減少効果は大きくなるものの、その減少量の増加は少ない。
したがって、長マークの再生信号には、マーク中心部に拡散性による変調度のくぼみと、マーク後方部に熱蓄積効果による変調度の増加部が見えることになるので、この変調度のくぼみ量や後方熱蓄積効果量の検出度合いは、再生光の分解能、すなわちビーム形状に依存することになる。これが原因で、拡散性の高い非環状化合物では、ビーム形状によって長マークの変調度のくぼみ量や後方熱蓄積効果量の検出度合いが異なり、したがって長マークの変調度が異なって見えるため、アシンメトリに波長依存性（正確に言えばビーム形状依存性）が生まれ、ジッタにも波長依存性（正確に言えばビーム形状依存性）が生まれる。
【００１８】
本発明では、このジッタの波長依存性を膜厚を最適化することで、低減させた光情報記録媒体の作製方法を提供するものである。
すなわち、前述したように、記録マークは主に記録層材料の分解による屈折率変化による位相増加成分と基板に近接した記録層材料の基板内への拡散による位相低下成分によって形成されている。
前記の記録層材料の分解による屈折率変化による位相差増加成分は、記録層全体で生じる体積的効果であるのに対し、基板に近接した記録層材料の基板内への拡散による位相低下成分は、略平面的効果であるため、ジッタのビ−ム径依存性をもたらす拡散寄与を再生信号から低減させるためには、記録層材料の分解による屈折率変化で生じる位相差増加成分を増大させ、相対的に拡散成分を低下させればよく、これは記録層膜厚を増加させることで達成されることを見出したものである。
また、拡散効果は記録マークに歪みを生じさせるわけであるから、長マークのピットデビエーションを増加させる。したがって、各記録マーク長ごとの単独ジッタは良好であっても、Ｄａｔａ ｔｏ Ｃｌｏｃｋジッタは悪化する場合がある。
しかし本発明の記録層膜厚の最適化によって、拡散性によるピットデビエーションを小さくすることが可能であるため、各記録マーク長ごとの単独ジッタとともにＤａｔａ ｔｏ Ｃｌｏｃｋジッタも低減させる効果もあわせもつ。
【００１９】
以下、本発明の実施例を示す。
【００２０】
【実施例】
厚さ０．６ｍｍ、トラックピッチ０．７４（ｕｍ）のポリカーボネート基板上（４．７ＧＢ対応）に下記化１の化合物をスピンコートによって成膜し、その上にスパッタにより金反射層、さらに紫外線硬化型樹脂からなる保護層を設け、光情報記録媒体を作成し（膜の最大吸収波長におけるＡｂｓ値で０．６６０、０．７１０、０．７６０、０．８８０の４種の膜厚のメディアを作成）、パルステック工業製のＤＤＵ−１０００〔波長６３５（ｎｍ）、ＮＡ０．６０〕により、記録パワーを８．０（ｍＷ）〜１１．０（ｍＷ）の範囲で０．５（ｍＷ）きざみで変化させて記録を行い、同波長での再生、およびパルステック工業製のＤＤＵ−１０００〔波長６５０（ｎｍ）、ＮＡ０．６０〕による再生を行い、Ｄａｔａ ｔｏ Ｃｌｏｃｋジッタの測定を行った。
【００２１】
【化１】
この理由は、前述のように、本実験で用いた記録材料が比較的大きな拡散性を示す材料であり、再生するＰＵＨのビーム形状によって記録マーク中の拡散性の見え方が異なるためである。
しかし膜厚を厚くしていくと、徐々に記録層内の記録材料の分解寄与分が記録層材料分解物の基板内拡散寄与分を補償していくため（記録材料分解物の基板内拡散は、基板と記録層界面近傍の分子が大きく寄与すると考えられる）、再生するＰＵＨのビーム形状によって記録マーク中の拡散性の見え方に差がなくなる。
【００２２】
本実験結果を見れば、この現象が明確に現れており、厚膜では記録ＰＵＨである６３５（ｎｍ）でのＤａｔａ ｔｏ Ｃｌｏｃｋジッタの最適記録パワーと、再生ＰＵＨである６５０（ｎｍ）でのＤａｔａ ｔｏ Ｃｌｏｃｋジッタの最適記録パワーが近づいていき、ある膜厚近傍で記録ＰＵＨである６３５（ｎｍ）と再生ＰＵＨである６５０（ｎｍ）でのＤａｔａ ｔｏ Ｃｌｏｃｋジッタの最適記録パワーが一致し、しかもＤａｔａ ｔｏ Ｃｌｏｃｋジッタの記録パワー依存性もほとんど一致していることが明瞭にわかる。
【００２３】
図１２は各膜厚での最適記録パワーを６３５（ｎｍ）と６５０（ｎｍ）において、それぞれプロットしたものである。この結果を見ても、膜厚を厚くしていくと、徐々に記録層内の記録材料の分解寄与分が記録層材料分解物の基板内拡散寄与分を補償していき（記録材料分解物の基板内拡散は、基板と記録層界面近傍の分子が大きく寄与すると考えられる）、再生するＰＵＨのビーム形状による記録マーク中の拡散性の見え方に差がなくなっていく様子がわかる。
また、それぞれの膜厚を有するサンプルの、８、９、１０、１１（ｍＷ）で記録した時の１４Ｔマーク再生信号を６３５（ｎｍ）と６５０（ｎｍ）で再生し比較すると、アゾ金属錯体化合物では６３５（ｎｍ）と６５０（ｎｍ）での再生による１４Ｔマーク形状が異なって見えており、これがジッタの波長依存性を大きくする理由である〔６５０（ｎｍ）のほうが後方熱蓄積効果による変調度の増加が大きく見える〕。この１４Ｔマークの差異は、マーク後方への熱蓄積効果の見え方の差とも言える。
【００２４】
ところで、アゾ金属錯体化合物の１４Ｔマークの再生信号を見ると、マーク中央部付近に変調度のくぼみ（変調度が小さい部分）が存在することがわかる。
記録マークには必ずマーク後方への熱伝導効果、言い換えれば後方への熱蓄積効果があるから、マーク前方に対してマーク後方は変調度が増加するのが自然である（いわゆる涙形マークの形成）。変調度のくぼみの発生は、マルチパルスによる記録でパルス長が極端に短くない限り発生しない。
またマルチパルスによる記録でパルス長を極端に短くした場合は、変調度のくぼみは発生するが、マーク後方の熱蓄積効果による変調度の増加部分が観測されない。したがって、アゾ金属錯体化合物に見えるような１４マークの変調度のくぼみは、まさしく拡散性による変調度抑制効果が存在する証拠でもある。
この１４Ｔマークに見られるような変調度のくぼみ、および熱蓄積効果によるマーク後方の変調度増加マーク（非対称マーク）は、１０Ｔ、１１Ｔ、１４Ｔ等のような長マークにおいてのみ観測される。
これは、ビーム径に対して十分な長さを有さない記録マークは、マーク内の平均的な変調度が検出されてしまうためである。
【００２５】
本実験結果では、最適記録パワーの記録層膜厚依存性が６３５（ｎｍ）よりも６５０（ｎｍ）のほうが大きいことから、厚膜化による拡散寄与分の補償効果が６５０（ｎｍ）でより有効であると言え、したがって６５０（ｎｍ）のＰＵＨのビーム径が６３５（ｎｍ）のＰＵＨのビーム径より小さいと判断できる。
すなわち、６５０（ｎｍ）のＰＵＨは６３５（ｎｍ）のＰＵＨよりも少なくともタンジェンシャル方向のビーム径状が小さいため、ビーム形状よりも十分長い記録マークを再生すると、記録マーク中の変調度の位置による変動を細かく捕らえるため、膜厚増加による拡散性低減効果がより顕著に見えるのである。
【００２６】
一方、下記化２の環状化合物であるポルフィラジン化合物では、低拡散性であるため、長マーク変調度のビーム形状依存性が少なくなり、ジッタの記録パワー依存曲線に再生波長依存性がほとんどないことが確認できた。図７〜図１１、および図１３に示すように、ジッタの記録パワー依存曲線が６３５（ｎｍ）と６５０（ｎｍ）でほとんど同じである。ただし図７〜１１は図３〜６と同様の実験結果を、図１３は図１２と同様の実験結果を示す。
これは、化２のポルフィラジン化合物を記録層とするサンプルの、７、８、９、１０（ｍＷ）で記録した時のそれぞれの１４Ｔマーク再生信号を６３５（ｎｍ）と６５０（ｎｍ）で再生比較すると、ポルフィラジン化合物では６３５（ｎｍ）と６５０（ｎｍ）での再生による１４Ｔマーク形状にほとんど差がないことによる。
【００２７】
また、化１の化合物をＡｂｓ値で０．８５近傍の膜厚値に設定して光情報記録媒体を作製することによって、図６に示すように、記録パワーを変えて記録した記録部を再生した場合、記録ＰＵＨにおけるジッタの記録パワー依存曲線のボトムとなる最適記録パワーＰｗと再生ＰＵＨにおけるジッタの記録パワー依存曲線のボトムとなる最適記録パワーＰｒとを等しくすることが可能となり（記録ＰＵＨでも再生ＰＵＨでも、記録パワーを変えて記録した複数の記録部のうち、同一の記録部が最良のジッタ値を示す）、再生ＰＵＨに依存しない互換性の非常に優れた光情報媒体を容易に得ることができる。これは同時に再生ＰＵＨに依存しない互換性の非常に優れた光情報媒体を容易に得るためには、本発明で規定した光情報記録媒体の作製方法が、すなわち複数の記録パワーで記録した部分の、異なる２つのＰＵＨ（最もビ−ム径の異なるＰＵＨを用いることが好ましく、一般的には記録ＰＵＨと再生ＰＵＨに相当する。）でのジッタの記録パワー依存性を調べ、両波長におけるジッタの記録パワー依存性が一致する膜厚に設定する方法が有効であることが検証できた。
【００２８】
【化２】
【効果】
本発明によれば、Ｄａｔａ ｔｏ Ｃｌｏｃｋジッタに波長依存性の少ない光情報記録媒体の作製方法が提供できる。したがって、記録装置でＯＰＣを行って最適記録を行えば、記録装置と波長あるいはビ−ム径の異なる再生装置（記録波長と再生波長が異なる場合だけでなく、記録再生波長が同一である場合の再生装置間の波長バラツキを含める）で再生した場合でも、記録部はどの再生装置にとっても最適に記録された領域であることが保証できる。すなわち、記録再生波長のずれや装置間の波長バラツキによるＤａｔａ ｔｏ Ｃｌｏｃｋジッタの変動が低減できるため、装置間の互換性も高く、非常に信頼性の高い光情報記録媒体が提供できる。
【図面の簡単な説明】
【図１】最適記録条件が記録ＰＵＨ（６３５ｎｍ）と再生ＰＵＨ（６５０ｎｍ）で大きく異なる場合が生じることをを示す図である。
（ａ）記録ＰＵＨ（６３５ｎｍ）の場合
（ｂ）記録ＰＵＨ（６５０ｎｍ）の場合
【図２】図２は、記録部形成のモデルを示す図である。
【図３】Ａｂｓ＝０．６６０における、６３５ｎｍと６５０ｎｍの記録パワーとデ−タｔｏクロックジッタ（％）の関係を示す図である。
【図４】Ａｂｓ＝０．７１０における、６３５ｎｍと６５０ｎｍの記録パワーとデ−タｔｏクロックジッタ（％）の関係を示す図である。
【図５】Ａｂｓ＝０．７６０における、６３５ｎｍと６５０ｎｍの記録パワーとデ−タｔｏクロックジッタ（％）の関係を示す図である。
【図６】Ａｂｓ＝０．８８０における、６３５ｎｍと６５０ｎｍの記録パワーとデ−タｔｏクロックジッタ（％）の関係を示す図である。
【図７】Ａｂｓ＝０．５８７における、６３５ｎｍと６５０ｎｍの記録パワーとデ−タｔｏクロックジッタ（％）の関係を示す図である。
【図８】Ａｂｓ＝０．６３９における、６３５ｎｍと６５０ｎｍの記録パワーとデ−タｔｏクロックジッタ（％）の関係を示す図である。
【図９】Ａｂｓ＝０．６９４における、６３５ｎｍと６５０ｎｍの記録パワーとデ−タｔｏクロックジッタ（％）の関係を示す図である。
【図１０】Ａｂｓ＝０．７５０における、６３５ｎｍと６５０ｎｍの記録パワーとデ−タｔｏクロックジッタ（％）の関係を示す図である。
【図１１】Ａｂｓ＝０．８０２における、６３５ｎｍと６５０ｎｍの記録パワーとデ−タｔｏクロックジッタ（％）の関係を示す図である。
【図１２】各膜厚での最適記録パワーを６３５（ｎｍ）と６５０（ｎｍ）において、それぞれプロットした図である。
【図１３】各膜厚での最適記録パワーを６３５（ｎｍ）と６５０（ｎｍ）において、それぞれプロットした図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical information recording medium, in particular, an optical information recording medium that can be recorded by laser light.How to makeAbout.
[0002]
[Prior art]
An optical information recording medium using an organic material has a large wavelength dependency of the complex refractive index. Therefore, when the wavelength is different, the reflectance, the modulation factor, the tracking signal, etc., and the jitter are also greatly different. Therefore, even when optimum recording is performed with a recording PUH (PUH: pickup head), there is a case where jitter is poor and greatly deviates from the standard value when reproduced with the reproduction PUH.
On the other hand, even when the recording area is optimal with the reproduction PUH (PUH: pickup head), there is a case where the jitter is poor when the reproduction is performed with the recording PUH.
Thus, in the case of an optical information recording medium in which the jitter greatly changes depending on the wavelength, at the present time, since the recording is performed so that the recording wavelength is optimized by OPC, the jitter at the reproduction wavelength is not guaranteed, There is a possibility that OPC at the time of recording becomes meaningless. For example, in the case of an optical information recording medium using a non-cyclic compound (for example, an azo metal complex compound) as a recording layer material (4.7 GB DVD-R), optimum recording is performed as shown in FIG. There are cases where the conditions are greatly different between the recording PUH (635 nm) and the reproduction PUH (650 nm) (in FIG. 1, the substantially circular curve represents the jitter value with contour lines, and the smaller the circle, the smaller the jitter value). . That is, in FIG. 1, in the reproduction with the recording PUH, the vicinity of the recording portion where the multipulse length is 0.66 (T) and the recording power is 10.8 (mW) shows the optimum jitter, whereas the reproduction PUH In the case of reproduction at 1, the multi-pulse length is 0.71 (T), the recording power is 11.1 (mW), and the vicinity of the recording portion shows optimum jitter.
However, FIG. 1 shows the recording PUH in the recording strategy described in DVD Specification for Recordable Disk (DVD-R) Part1 PHYSICAL SPECIFICATIONS Version 1.0 July 1997. Data to Clock jitter due to reproduction in the reproduction and reproduction in the reproduction PUH was measured in each recording condition section.
[0003]
Further, even if the recording PUH and the reproducing PUH are the same optical information recording medium according to the standard, the oscillation wavelength has a certain finite wavelength range due to individual differences of lasers, environmental temperature, laser intensity, etc. Although there is a magnitude of wavelength dependence, there is a possibility that a difference in jitter may occur due to wavelength variation as in the case where the wavelength differs between the recording PUH and the reproduction PUH described above, so that the reproduction compatibility between the recording apparatus and the reproduction apparatus is high. There is a risk of not being able to keep enough.
Furthermore, since the rim intensity is generally different between the recording PUH and the reproduction PUH (apparatus capable of reproduction only), the beam diameter is different, and the reproduction compatibility between the recording apparatus and the reproduction apparatus is not sufficiently maintained. There is a risk.
[0004]
[Problems to be solved by the invention]
The present invention relates to an optical information recording medium using an organic material.How to makeOptical information recording medium with high reproduction compatibility and very high reliabilityHow to makeThe purpose is to provide.
That is, an optical information recording medium that prevents the appearance of a reproduced signal from being different due to differences in reproduction wavelength, wavelength variation, beam size, etc., and that can provide good jitter regardless of which device is used.How to makeIn particular, in the case of an optical information recording medium based on the DVD-R standard, an optical information recording medium having substantially the same jitter characteristics when reproduced by either recording PUH or reproduction PUH.How to makeThe purpose is to provide.
[0005]
[Means for Solving the Problems]
The problem isOptimize the recording layer thickness of optical information recording mediaBy the following inventionI was able to solve it.
That is, the first of the present invention isAn optical information recording medium in which a recording layer is mainly composed of an acyclic compound, which performs recording and reproduction by a first laser and uses a recording PUH in which the recording power of the first laser is variable in a plurality of stages, after production In the method for producing an optical information recording medium in which recording is performed on the recording layer and reproduction is performed using a reproduction PUH that performs reproduction only by a second laser.
For each of a plurality of types having different film thicknesses of the recording layer, recording is performed with a plurality of levels of recording power using the recording PUH, and jitter is minimized when reproduction is performed using the recording PUH. A step of determining the optimum recording power Pw at which recording is performed for each of a plurality of types having different film thicknesses;
For each of a plurality of types having different film thicknesses of the recording layer, recording is performed at a plurality of levels of recording power using the recording PUH, and jitter is minimized when reproduction is performed using the reproduction PUH. A step of obtaining the optimum recording power Pr for recording in such a manner for each of a plurality of types having different film thicknesses;
Based on the plurality of optimum recording powers Pw obtained for the plurality of types having different film thicknesses and the plurality of optimum recording powers Pr obtained for the plurality of types having different film thicknesses, the optimum recording power Pw and the optimum recording power. Obtaining the film thickness that minimizes the difference from the power Pr;
Forming the recording layer such that the difference obtained is a minimum film thickness;
A method for producing an optical information recording medium.
[0006]
The second of the present invention isThe step of obtaining the optimum recording power Pw is performed by the recording PUH for each of the plurality of optical information recording media prepared for each film thickness and recorded by the recording power at each stage. The recording power corresponding to the minimum jitter among the plurality of determined jitters is set as the optimum recording power Pw at the film thickness. This is a method for producing an optical information recording medium.
According to a third aspect of the present invention, in the step of obtaining the optimum recording power Pr, for each of the plurality of optical information recording media prepared for each film thickness and recorded with the recording power at each stage, Jitter is obtained when reproduction is performed by the reproduction PUH, and the recording power corresponding to the minimum jitter among the obtained plurality of jitters is set as the optimum recording power Pr for the film thickness. The method for producing an optical information recording medium according to
[0007]
Hereinafter, the present invention will be described in detail.
As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the reason why the jitter characteristics differ greatly between the recording PUH and the reproduction PUH as described above is that the difference in the reproduction beam diameter and the large wavelength dependence of the organic material. In addition, it was found that the recording mark phase formation mechanism exists, and the present invention has been achieved.
That is, the cause of the jitter greatly differing in the PUH wavelength to be reproduced is that the asymmetry differs depending on the PUH wavelength to be reproduced. This is because the beam diameters of the reproduction laser beam and the recording laser beam are different, and the recording material enters the substrate. When the diffusivity of the recording layer is high, it is found that the above phenomenon appears remarkably (the contribution of the refractive index of the recording layer material due to the wavelength dependency is small).
[0008]
When the beam diameters of the reproduction laser beam and the recording laser beam are different, first of all, there may be a case where the recording wavelength and the reproduction wavelength are different, or a case where the NA is different, but the present invention is not limited to these cases. And the reproduction wavelength are also applied to optical information recording media whose standards are the same. In other words, the wavelength of the semiconductor laser may vary greatly depending on manufacturing variations, environmental temperature, and recording / reproducing power, so that even if the recording wavelength and the reproducing wavelength are the same in the standard, they have the same beam shape. There is no guarantee. Also, the rim intensity is usually different because the recording beam diameter needs to be shaped so as to obtain a high output in order to decompose the recording material, and the reproducing beam diameter needs to be shaped so that the ROM can be reproduced best. This is because the recording beam shape and the reproducing beam shape are generally different, and the wavelength variation and the beam diameter variation between the reproducing apparatuses are not zero.
Therefore, when optimizing the film thickness in the present invention, if the recording wavelength and the reproducing wavelength are different, it is sufficient to optimize the recording layer film thickness with the representative apparatuses of both, while the recording wavelength and the reproducing wavelength are sufficient. If the wavelengths are the same, use a device with a wavelength shift or beam shape within a conceivable range (generally, matching between the recording PUH and the read-only PUH may be achieved), and the recording layer thickness Can be optimized.
For example, DVD Specification for Recordable Disk (DVD-R) Part 1 PHYSICAL SPECIFICATIONS Version 1.0 July 1997 has a description that the wavelength distribution of 10 (nm) is permitted with respect to the reproduction wavelength. In fact, it has a larger wavelength distribution. Therefore, even if the recording wavelength and the reproduction wavelength are the same according to the standard, the difference in beam diameter due to the above-described wavelength variation and the difference in beam diameter due to the difference in rim intensity are added. Reproduction characteristics can vary greatly.
This is because even if the same media is evaluated using a DVD player or an evaluation device of each manufacturer, not only the absolute value of the jitter value fluctuates within a small range but also the jitter value varies greatly or different recording is performed. It can be easily estimated from the fact that when the condition part is reproduced, the case where the dependency of the jitter on the recording condition is completely different often occurs.
[0009]
The reason why the jitter is greatly different in the PUH to be reproduced is because of the difference in the PUH wavelength at the time of reproduction described above (basically, the beam diameter is important. The beam diameter also generally changes when the wavelength is different) and the rim intensity. One reason is that the beam diameter varies depending on the difference, but when the diffusibility of the recording material into the substrate is small, the wavelength dependency of jitter can be reduced.
That is, in a system in which the beam diameter of PUH at the time of reproduction differs between apparatuses (the reproduction beam diameters at the recording PUH and the reproduction PUH are different. Also, the reproduction PUH should normally be different within a certain range). When a recording material with high performance or a disk configuration with high diffusivity is used, the dependency of jitter on reproduction PUH increases.
[0010]
Hereinafter, the diffusibility of the recording material will be described.
Here, the diffusibility refers to a phenomenon in which a decomposition product of the recording layer material diffuses into the expanded substrate, and the optical phase difference in consideration of the diffusivity is expressed as follows. That is, as shown in FIG. 2, by recording, bumps are formed on the substrate, and at the same time, pits are formed at the interface between the reflective layer and the recording layer, and the refractive index change due to recording of the recording layer is averaged in the recording layer. Refractive index (nd-Δnd), The optical phase is expressed as follows.
[0011]
[Expression 1]
(1) Bump formation (interface between substrate and recording layer)
(2): Pit formation (substrate and reflective layer interface)
(3): Substrate refractive index drop (due to bump formation)
(4): Refractive index drop of recording layer (due to decomposition)
[0012]
That is, in the case of a recording material in which diffusion does not occur, the phase differences due to all the terms (1), (2), (3), and (4) are added. In the case of a recording material in which diffusion occurs, volume expansion occurs due to diffusion. As a result of the decomposition of the recording layer material being diffused in the substrate where the refractive index has been lowered (part where the bumps are formed), the decrease in the refractive index of the substrate is canceled, and the refractive index of the recording layer is also the same as that of the recording layer material. The degradation product diffuses into the substrate, so that the decrease is reduced. That is, in the case of a recording material in which diffusion occurs, an optical phase difference is caused by the numerical expression (1) (2) (the contribution of (3) (4) is small). From this, it is understood that the degree of modulation of the recording material in which diffusion occurs is smaller than that of the recording material in which diffusion does not occur.
Here, it is described that only the decomposition product of the recording layer material diffuses into the substrate by recording, but in reality, the recording layer material is melted by the substrate or the recording material, particularly in the vicinity of the front, rear, left and right edges of the recording mark. Undecomposed products and by-products diffuse into the substrate together with the decomposed products. However, the undecomposed product and by-product of the recording layer material are generally considered to be incompatible with the substrate material at the molecular level because the molecules are large and retain electronic interaction force. It is considered that the ability to compensate for the refractive index decrease due to volume expansion is lower than the decomposition product.
[0013]
The existence of this phenomenon of diffusion can be proved by actually estimating the optical phase difference of the recording portion. For example, the optical phase difference is calculated using the following values (reference: Jpn. J. Appl. Phys. Vol. 31 (1992) Pt. 1, No. 2B pp 484-493).
-Substrate refractive index ns= 1.57, the refractive index of the recording layer is nd= 2.70
・ Bump height dB= 60 (nm),
Pit depth dP= 7 (nm): Observation by SEM or the like
・ The refractive index of the dye changes to 1.5 due to decomposition.
Decomposition equivalent film thickness of 70 (nm): Change in optical characteristics of the recording part is converted into film thickness value
・ About 20% d by bumpBIncreased: from Clausius Mosotiequation
[Expression 2]
Further, the refractive index lowering region is set to 300 (nm).
∴δOPD ′ = 136 + 38 + 66 + 168 = 408 (nm) >> λ / 2 = 635/2, and the modulation degree is
[Equation 3]
[0014]
In the case of a write-once type optical information recording medium using an organic material as described above, it is necessary to consider the diffusibility, but the size of this diffusivity depends on the ease of diffusion of the recording layer material itself and the substrate groove shape. It is thought that.
For example, macrocyclic compounds such as tetraazaporphyrin derivatives have a strong basic skeleton, a small number of units that decompose during decomposition, and a large number of decomposed units (substituent bonds are broken by recording, and this relatively small decomposed product Mainly diffuses into the substrate). On the other hand, an acyclic compound such as an azo metal complex has a large number of units that decompose at the time of decomposition, and each decomposition product unit is relatively small.
Therefore, cyclic compounds such as tetraazaporphyrin derivatives exhibit low diffusivity, and non-cyclic compounds such as azo metal complexes tend to exhibit high diffusivity.
[0015]
In addition, since it is considered that the portion of the recording layer that comes into contact with the substrate is most likely to be diffused, the appearance of the diffusion effect varies depending on the groove shape (width and depth) of the substrate. The phase difference due to recording is mainly caused by the refractive index change due to the decomposition of the recording layer material, and the diffusion effect works in the direction to suppress the phase difference generation due to this refractive index change. It has occurred.
[0016]
Consider a case where an optical information recording medium made of a highly diffusible recording material is reproduced with different wavelengths, that is, with different beam shapes.
For short recording marks such as 3T, 4T, etc. with respect to the reproduction beam shape, for example, when the front of the beam approaches the back of the recording portion, the entire mark is contained in the beam. Cannot be reproduced separately (no resolution), and only an average signal of the entire short mark can be obtained.
Therefore, in the short mark, although there is a heat accumulation effect behind the mark, the modulation degree behind the mark does not increase with respect to the front, and the phase distribution with respect to the scanning direction of the beam appears symmetric.
On the other hand, long recording marks such as 11T and 14T with respect to the playback beam diameter are long because, for example, when the front of the beam approaches the back of the recording portion, the entire mark does not fit in the beam. Since the phase position distribution in the mark can be separated and reproduced within a certain range (having resolution), a signal in accordance with the reproduction position can be obtained. Therefore, in the long mark, a mark in which the degree of modulation behind the mark increases with respect to the front due to the heat accumulation effect behind the mark is observed, and the phase distribution in the beam scanning direction appears asymmetric. As described above, since the phase distribution in the recording mark is detected with a certain degree of resolution in the long mark, a decrease in the degree of modulation due to the diffusibility in the recording mark is also detected.
[0017]
The recording mark is mainly composed of a phase increasing component due to a change in refractive index due to decomposition of the recording layer material and a modulation degree decreasing component due to diffusibility.
The contribution to increase in modulation due to the decomposition of the recording layer material increases behind the mark due to the backward heat accumulation effect, while the contribution to decrease in modulation due to diffusivity contributes to diffusion with respect to the recording layer region contributing to refractive index change. Since the recording layer area that contributes is small, the modulation degree reduction effect increases toward the rear of the mark, but the increase in the reduction amount is small.
Therefore, in the reproduction signal of the long mark, a depression of the modulation degree due to the diffusibility is seen at the center of the mark and an increase in the modulation degree due to the heat accumulation effect is seen at the rear of the mark. The degree of detection of the amount of back heat accumulation effect depends on the resolution of the reproduction light, that is, the beam shape. For this reason, in the non-cyclic compound with high diffusibility, the depth of modulation of the long mark modulation degree and the degree of detection of the back heat accumulation effect amount differ depending on the beam shape, and therefore the modulation degree of the long mark looks different. Wavelength dependency (more precisely, beam shape dependency) is born, and jitter also has wavelength dependency (more precisely, beam shape dependency).
[0018]
In the present invention, the wavelength dependence of this jitter is reduced by optimizing the film thickness, thereby reducing the optical information recording medium.How to makeIs to provide.
That is, as described above, the recording mark is mainly formed by a phase increasing component due to a change in refractive index due to decomposition of the recording layer material and a phase decreasing component due to diffusion of the recording layer material adjacent to the substrate into the substrate.
The phase difference increasing component due to the refractive index change due to the decomposition of the recording layer material is a volume effect generated in the entire recording layer, whereas the phase decreasing component due to diffusion of the recording layer material close to the substrate into the substrate is In order to reduce the diffusion contribution resulting from the beam diameter dependence of jitter from the reproduction signal because it is a substantially planar effect, the phase difference increasing component caused by the refractive index change due to the decomposition of the recording layer material is increased, It has only been found that the diffusion component should be relatively lowered, and this has been found to be achieved by increasing the film thickness of the recording layer.
Further, since the diffusion effect causes distortion in the recording mark, the pit deviation of the long mark is increased. Therefore, even if the single jitter for each recording mark length is good, the Data to Clock jitter may deteriorate.
However, since the pit deviation due to diffusibility can be reduced by optimizing the recording layer thickness of the present invention, it has the effect of reducing Data to Clock jitter as well as single jitter for each recording mark length.
[0019]
Examples of the present invention will be described below.
[0020]
【Example】
A compound of the following chemical formula 1 is formed on a polycarbonate substrate (corresponding to 4.7 GB) having a thickness of 0.6 mm and a track pitch of 0.74 (um) by spin coating, a gold reflective layer is sputtered thereon, and further UV-cured. An optical information recording medium is prepared by providing a protective layer made of a mold resin (abs values at the maximum absorption wavelength of the film are 0.660, 0.710, 0.760, and 0.880). Preparation), DDU-1000 manufactured by Pulstec Industrial Co., Ltd. (wavelength 635 (nm), NA 0.60), recording power in the range of 8.0 (mW) to 11.0 (mW) in 0.5 (mW) increments And recording with the same wavelength, and reproduction with DDU-1000 [wavelength 650 (nm), NA 0.60] manufactured by Pulstec Industrial Co., Ltd., and Data to Clock jitter Was measured.
[0021]
[Chemical 1]
This is because, as described above, the recording material used in this experiment is a material exhibiting a relatively large diffusibility, and the appearance of the diffusibility in the recording mark differs depending on the beam shape of the PUH to be reproduced.
However, as the film thickness is increased, the decomposition contribution of the recording material in the recording layer gradually compensates for the diffusion contribution in the substrate of the recording layer material decomposition product (the diffusion of the recording material decomposition product in the substrate is It is thought that molecules near the interface between the substrate and the recording layer contribute significantly), and the difference in the appearance of the diffusibility in the recording mark is eliminated depending on the beam shape of the PUH to be reproduced.
[0022]
From this experimental result, this phenomenon clearly appears. In the case of a thick film, the optimum recording power of Data to Clock jitter at 635 (nm) which is the recording PUH and the data at 650 (nm) which is the reproducing PUH. The optimum recording power of the to clock jitter approaches, and the optimum recording power of the data to clock jitter at the recording PUH of 635 (nm) and the reproduction PUH of 650 (nm) coincide with each other in the vicinity of a certain film thickness. It can be clearly seen that the recording power dependence of to clock jitter is almost the same.
[0023]
FIG. 12 is a plot of the optimum recording power at each film thickness at 635 (nm) and 650 (nm). From this result, as the film thickness is increased, the decomposition contribution of the recording material in the recording layer gradually compensates for the diffusion contribution in the substrate of the recording layer material decomposition product (recording material decomposition product). It can be understood that the diffusion in the substrate is greatly influenced by molecules near the interface between the substrate and the recording layer), and the difference in the appearance of the diffusibility in the recording mark due to the beam shape of the PUH to be reproduced disappears.
Further, when the 14T mark reproduction signals of samples having respective film thicknesses recorded at 8, 9, 10, 11 (mW) were reproduced at 635 (nm) and 650 (nm) and compared, the azo metal complex compound However, the 14T mark shape due to reproduction at 635 (nm) and 650 (nm) looks different, which is the reason why the wavelength dependence of jitter is increased [650 (nm) is the modulation factor due to the backward heat accumulation effect. The increase in This 14T mark difference can be said to be a difference in the appearance of the heat accumulation effect behind the mark.
[0024]
By the way, when the reproduction signal of the 14T mark of the azo metal complex compound is seen, it can be seen that a depression with a modulation degree (a part with a low modulation degree) exists near the center of the mark.
The recorded mark always has a heat conduction effect behind the mark, in other words, a heat accumulation effect behind it, so it is natural that the degree of modulation increases behind the mark in front of the mark (formation of so-called tear marks) ). The generation of the modulation degree dent does not occur unless the pulse length is extremely short in multi-pulse recording.
In addition, when the pulse length is extremely shortened by multi-pulse recording, a depression in the modulation degree occurs, but an increase in the modulation degree due to the heat accumulation effect behind the mark is not observed. Therefore, the depression of the modulation degree of 14 marks that appears to be an azo metal complex compound is also evidence that the modulation degree suppression effect due to diffusibility exists.
The depression of the modulation degree as seen in the 14T mark and the modulation degree increase mark (asymmetric mark) behind the mark due to the heat accumulation effect are observed only in the long mark such as 10T, 11T, 14T and the like.
This is because an average modulation degree in the mark is detected for a recording mark that does not have a sufficient length with respect to the beam diameter.
[0025]
In this experimental result, since the dependence of the optimum recording power on the recording layer thickness is larger at 650 (nm) than at 635 (nm), the compensation effect of the diffusion contribution due to the thick film is more effective at 650 (nm). Therefore, it can be determined that the beam diameter of the PUH of 650 (nm) is smaller than the beam diameter of the PUH of 635 (nm).
That is, since the 650 (nm) PUH has a smaller beam diameter in the tangential direction than the 635 (nm) PUH, when a recording mark sufficiently longer than the beam shape is reproduced, it depends on the position of the modulation degree in the recording mark. Since fluctuations are captured in detail, the effect of reducing the diffusivity due to the increase in film thickness appears more prominent.
[0026]
On the other hand, the porphyrazine compound, which is a cyclic compound of the
This is a sample using the porphyrazine compound of
[0027]
In addition, by forming an optical information recording medium by setting the compound of Chemical Formula 1 to a film thickness value of about 0.85 in terms of Abs value, the recording portion recorded with different recording power can be reproduced as shown in FIG. In this case, the optimum recording power Pw which is the bottom of the recording power dependence curve of jitter in the recording PUH can be made equal to the optimum recording power Pr which is the bottom of the recording power dependence curve of jitter in the reproduction PUH (even in the recording PUH). Even in the reproduction PUH, among the plurality of recording units recorded with different recording powers, the same recording unit shows the best jitter value), and an optical information medium having excellent compatibility that does not depend on the reproduction PUH is easily obtained. be able to. At the same time, in order to easily obtain an optical information medium having excellent compatibility that does not depend on the reproduction PUH, the method for producing an optical information recording medium defined in the present invention, that is, a portion recorded with a plurality of recording powers is used. Then, the recording power dependency of jitter in two different PUHs (preferably PUHs having the most different beam diameters are used, generally corresponding to recording PUHs and reproducing PUHs) is examined, and jitters at both wavelengths are examined. It was verified that the method of setting the film thickness with the same recording power dependency was effective.
[0028]
[Chemical 2]
【effect】
The present inventionAccording to, Optical information recording medium with less wavelength dependence on Data to Clock jitterHow to makeCan be provided. Therefore,RecordIf optimal recording is performed by performing OPC in the recording device, a reproducing device having a wavelength or beam diameter different from that of the recording device (not only when the recording wavelength and the reproducing wavelength are different, but also when the recording / reproducing wavelength is the same) Even in the case of reproduction with a wavelength variation between them, it can be assured that the recording unit is an optimally recorded area for any reproducing apparatus. That is, since fluctuations in Data to Clock jitter due to deviations in recording / reproducing wavelengths and wavelength variations between apparatuses can be reduced, an optical information recording medium with high compatibility between apparatuses and a very high reliability can be provided.
[Brief description of the drawings]
FIG. 1 is a diagram showing that an optimum recording condition may greatly differ between a recording PUH (635 nm) and a reproduction PUH (650 nm).
(A) In the case of recording PUH (635 nm)
(B) Recording PUH (650 nm)
FIG. 2 is a diagram illustrating a model for forming a recording unit.
FIG. 3 is a diagram showing a relationship between recording power at 635 nm and 650 nm and data to clock jitter (%) when Abs = 0.660.
FIG. 4 is a diagram showing the relationship between recording power at 635 nm and 650 nm and data to clock jitter (%) when Abs = 0.710.
FIG. 5 is a diagram showing the relationship between recording power at 635 nm and 650 nm and data to clock jitter (%) when Abs = 0.760.
FIG. 6 is a diagram showing the relationship between recording power at 635 nm and 650 nm and data to clock jitter (%) when Abs = 0.880.
FIG. 7 is a diagram showing the relationship between recording power at 635 nm and 650 nm and data to clock jitter (%) when Abs = 0.588.
FIG. 8 is a diagram showing a relationship between recording power at 635 nm and 650 nm and data to clock jitter (%) when Abs = 0.539.
FIG. 9 is a diagram showing the relationship between recording power at 635 nm and 650 nm and data to clock jitter (%) when Abs = 0.694.
FIG. 10 is a diagram showing a relationship between recording power at 635 nm and 650 nm and data to clock jitter (%) when Abs = 0.750.
FIG. 11 is a diagram showing the relationship between recording power at 635 nm and 650 nm and data to clock jitter (%) when Abs = 0.802.
FIG. 12 is a diagram in which optimum recording power at each film thickness is plotted at 635 (nm) and 650 (nm), respectively.
FIG. 13 is a diagram in which optimum recording power at each film thickness is plotted at 635 (nm) and 650 (nm), respectively.
Claims (3)
前記記録層の膜厚が異なる複数種のそれぞれに対して、前記記録ＰＵＨを用いて複数段階の記録パワーで記録を行い、前記記録ＰＵＨを用いて再生が為されたときのジッタが最小となるように記録が為される最適記録パワーＰｗを、前記膜厚が異なる複数種毎に求める工程と、For each of a plurality of types having different film thicknesses of the recording layer, recording is performed with a plurality of levels of recording power using the recording PUH, and jitter is minimized when reproduction is performed using the recording PUH. A step of determining the optimum recording power Pw at which recording is performed for each of a plurality of types having different film thicknesses;
前記記録層の膜厚が異なる複数種のそれぞれに対して、前記記録ＰＵＨを用いて複数段階の記録パワーで記録を行い、前記再生ＰＵＨを用いて再生が為されたときのジッタが最小となるように記録が為される最適記録パワーＰｒを、前記膜厚が異なる複数種毎に求める工程と、For each of a plurality of types having different film thicknesses of the recording layer, recording is performed at a plurality of levels of recording power using the recording PUH, and jitter is minimized when reproduction is performed using the reproduction PUH. A step of determining the optimum recording power Pr to be recorded for each of a plurality of types having different film thicknesses;
前記膜厚が異なる複数種毎に求めた複数の前記最適記録パワーＰｗおよび前記膜厚が異なる複数種毎に求めた複数の前記最適記録パワーＰｒに基づいて、前記最適記録パワーＰｗと前記最適記録パワーＰｒとの差が最小となる前記膜厚を求める工程と、Based on the plurality of optimum recording powers Pw obtained for the plurality of types having different film thicknesses and the plurality of optimum recording powers Pr obtained for the plurality of types having different film thicknesses, the optimum recording power Pw and the optimum recording power. Obtaining the film thickness that minimizes the difference from the power Pr;
求めた前記差が最小となる膜厚となるように、前記記録層を形成する工程と、Forming the recording layer such that the difference obtained is a minimum film thickness;
を備えたことを特徴とする光情報記録媒体の作製方法。A method for producing an optical information recording medium, comprising:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28490499A JP3983944B2 (en) | 1999-10-05 | 1999-10-05 | Method for producing optical information recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28490499A JP3983944B2 (en) | 1999-10-05 | 1999-10-05 | Method for producing optical information recording medium |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| JP2001110089A JP2001110089A (en) | 2001-04-20 |
| JP2001110089A5 JP2001110089A5 (en) | 2004-10-14 |
| JP3983944B2 true JP3983944B2 (en) | 2007-09-26 |
Family
ID=17684563
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP28490499A Expired - Fee Related JP3983944B2 (en) | 1999-10-05 | 1999-10-05 | Method for producing optical information recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3983944B2 (en) |
-
1999
- 1999-10-05 JP JP28490499A patent/JP3983944B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JP2001110089A (en) | 2001-04-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6232036B1 (en) | Optical recording disk | |
| JP4201006B2 (en) | Optical recording medium | |
| EP0996123A2 (en) | Optical recording medium and optical recording method | |
| KR19990023284A (en) | Optical information recording medium | |
| US20020051416A1 (en) | Optical recording method and optical recording medium | |
| EP0949612B1 (en) | An optical recording medium | |
| WO2001059778A1 (en) | Optical information recording medium | |
| JP3983944B2 (en) | Method for producing optical information recording medium | |
| JP2001273636A (en) | Optical recording method | |
| JP2002150563A (en) | Method and medium for optical recording | |
| Min et al. | New digital versatile disc recordable (DVD-R) with metal thin film and organic film on polycarbonate | |
| WO2007089041A1 (en) | Optical information recording medium, manufacturing method thereof, and recording method | |
| JP3543464B2 (en) | Optical recording medium and information recording method | |
| JP3028520B2 (en) | Optical information recording medium | |
| JP2004303401A (en) | Device and method to optically record and reproduce dyestuff draw type dvd medium | |
| JP4076453B2 (en) | Optical recording method for dye-based recordable DVD medium | |
| JP4135361B2 (en) | Optical recording method | |
| JP5336155B2 (en) | Optical information recording apparatus and method | |
| JP2004127472A (en) | Optical recording medium and its recording method | |
| JP4089868B2 (en) | Optical recording medium and optical recording method | |
| JP2003034078A (en) | Photorecording medium | |
| JP4060543B2 (en) | Optical recording medium | |
| JP3971561B2 (en) | Optical recording medium | |
| JP4223196B2 (en) | Optical recording medium, recording / reproducing method thereof, and optical recording apparatus | |
| JP2003248926A (en) | Optical recording method and optical recording medium |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20040712 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20040824 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20041025 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20061031 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20061225 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20070703 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20070705 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20100713 Year of fee payment: 3 |
|
| R150 | Certificate of patent or registration of utility model |
Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20110713 Year of fee payment: 4 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120713 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20120713 Year of fee payment: 5 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130713 Year of fee payment: 6 |
|
| LAPS | Cancellation because of no payment of annual fees |