JP4157425B2 - Organic functional thin film, manufacturing method thereof, and optical recording medium provided with organic functional thin film - Google Patents

Description

【００１８】
請求項４の構成によれば、脱離した置換基が気化しやすく、ミクロ相分離構造が壊されることがなく、均一なナノメータサイズの空孔が形成される。これにより、機能性色素を導入した場合に秩序化された構造の有機機能薄膜が得られ、例えば、光記録媒体の記録層、特に高密度記録用として有用な記録材料が提供される。
【００１９】
請求項５の発明は、互いに非相溶であるポリマー鎖が結合したブロック共重合体により形成されたミクロ相分離構造を有し、該ミクロ相分離構造の一方の分離相を形成するポリマー鎖が酸触媒により脱離可能な置換基を有し、該置換基の脱離によって形成された空孔に機能性色素を含有する有機機能薄膜の製造方法であって、
前記ブロック共重合体を含有する溶液を調製し、該調製された溶液を塗布薄膜化してミクロ相分離構造を有する有機薄膜を形成する工程と、
該有機薄膜に酸を接触させる工程と、
該有機薄膜を加熱して接触させた酸触媒により、前記ポリマー鎖に結合した置換基を脱離させて空孔を形成する工程と、
該空孔に機能性色素を含有させる工程と、
を含むことを特徴とする有機機能薄膜の製造方法である。
【００２０】
請求項６の発明は、互いに非相溶であるポリマー鎖が結合したブロック共重合体により形成されたミクロ相分離構造を有し、該ミクロ相分離構造の一方の分離相を形成するポリマー鎖が酸触媒により脱離可能な置換基を有し、該置換基の脱離によって形成された空孔に機能性色素を含有する有機機能薄膜の製造方法であって、
前記ブロック共重合体を含有する溶液を調製し、該調製された溶液を塗布薄膜化してミクロ相分離構造を有する有機薄膜を形成する工程と、
該有機薄膜に光酸発生剤を接触させる工程と、
該有機薄膜に光照射をした後に加熱して接触させた光酸発生剤から発生した酸により、前記ポリマー鎖に結合した置換基を脱離させて空孔を形成する工程と、
該空孔に機能性色素を含有させる工程と、
を含むことを特徴とする有機機能薄膜の製造方法である。
【００２１】
請求項７の発明は、互いに非相溶であるポリマー鎖が結合したブロック共重合体により形成されたミクロ相分離構造を有し、該ミクロ相分離構造の一方の分離相を形成するポリマー鎖が酸触媒により脱離可能な置換基を有し、該置換基の脱離によって形成された空孔に機能性色素を含有する有機機能薄膜の製造方法であって、
前記ブロック共重合体と、前記脱離可能な置換基を有するポリマー鎖が形成する分離相にのみ相溶性のある光酸発生剤とを含有する溶液を調製し、該調製された溶液を塗布薄膜化してミクロ相分離構造を有する有機薄膜を形成する工程と、
該有機薄膜に光照射をした後に加熱して含有する光酸発生剤から発生した酸により、前記ポリマー鎖に結合した置換基を脱離させて空孔を形成する工程と、
該空孔に機能性色素を含有させる工程と、
を含むことを特徴とする有機機能薄膜の製造方法である。
【００２２】
請求項８の発明は、互いに非相溶であるポリマー鎖が結合したブロック共重合体により形成されたミクロ相分離構造を有し、該ミクロ相分離構造の一方の分離相を形成するポリマー鎖が酸触媒により脱離可能な置換基を有し、該置換基の脱離によって形成された空孔に機能性色素を含有する有機機能薄膜の製造方法であって、
前記ブロック共重合体を含有する溶液を調製し、該調製された溶液を塗布薄膜化してミクロ相分離構造を有する有機薄膜を形成する工程と、
該有機薄膜に熱酸発生剤を接触させる工程と、
該有機薄膜を加熱して接触させた熱酸発生剤から発生した酸により、前記ポリマー鎖に結合した置換基を脱離させて空孔を形成する工程と、
該空孔に機能性色素を含有させる工程と、
を含むことを特徴とする有機機能薄膜の製造方法である。
【００２３】
請求項５〜８の製造方法によれば、機能性色素を、ブロック共重合体のミクロ相分離構造における所望とする分離相に形成されたナノメータサイズの空孔に、高度に秩序化された構造に制御して選択的に含有させることが可能となる。
このよう構造制御して複合化することにより、光学的性質、電子的性質、電気導電的性質等の新機能を発揮する有機機能薄膜の製造が達成される。また、超高密度記録に対応できる本発明の光記録媒体の製造を可能とすることができる。
【００２４】
請求項９の発明は、前記ミクロ相分離構造は、溶媒キャスト、もしくは温度変化により形成されることを特徴とする請求項５〜８のいずれかに記載の有機機能薄膜の製造方法である。
【００２５】
請求項９の構成によれば、簡便にミクロ相分離構造の形成ができ、有機機能薄膜を形成するための前駆体として具備すべき構造と構成を備えた有機薄膜が得られる。
【００２６】
請求項１０の発明は、前記空孔に機能性色素を含有させる工程が、溶媒を用いる湿式法により行われることを特徴とする請求項５〜９のいずれかに記載の有機機能薄膜の製造方法である。
【００２７】
請求項１０によれば、適応対象物やその素材の組合せ、あるいは製造工程に応じて処方が選択されるので、機能性色素を所望とする分離相の空孔に、秩序化された構造に制御して選択的に含有させることが可能となる。これによって、ナノメータサイズのドット列化が実現し、例えば、記録材料として用いた場合に超高密度記録に対応できる本発明の光記録媒体の製造を可能とすることが可能になる。
【００２８】
請求項１１の発明は、基板上に有機機能薄膜からなる記録層を設けた光記録媒体であって、
前記有機機能薄膜は、互いに非相溶であるポリマー鎖が結合したブロック共重合体により形成されたミクロ相分離構造を有し、該ミクロ相分離構造の一方の分離相を形成するポリマー鎖が脱離可能な置換基を有し、該置換基の脱離によって形成された空孔に機能性色素を含有したことを特徴とする光記録媒体である。
【００２９】
請求項１１によれば、光記録媒体の記録層中の機能性色素から構成される記録用のドット（記録ドット）がナノメータサイズで均一に形成されるため、超高密度の記録が可能となる。
【００３０】
請求項１２の発明は、基板上に、互いに非相溶であるポリマー鎖が結合したブロック共重合体により形成されたミクロ相分離構造を有し、該ミクロ相分離構造の一方の分離相を形成するポリマー鎖が脱離可能な置換基を有し、該置換基の脱離によって形成された空孔に機能性色素を含有する有機機能薄膜からなる記録層を設け、レーザ光を照射して該機能性色素の光学特性を変化させて記録再生することを特徴とする光記録媒体である。
【００３１】
請求項１２によれば、光記録媒体の記録層中の記録ドットがナノメータサイズで均一に形成され、照射されるレーザ光の発振波長やレンズのＮＡに依存することなく、ナノメータサイズの微小記録を実現し、超高密度の記録が可能となる。更に、記録ピットの最外周エッジも不明瞭となることなく優れた信号特性を得ることが可能となる。
更に、記録ピットの最外周エッジもこの有機薄膜の記録層ドット全体を変化させるように記録することで、従来のレーザビームのガウス分布などの要因に基づく記録ピットの最外周エッジの不明瞭さなどの問題も回避され、記録ピットのバラツキの無い高品質の信号特性を得ることが可能となる。
【００３２】
請求項１３の発明は、前記機能性色素は、記録再生用レーザの波長近傍に最大吸収波長を持つように波長制御した色素であることを特徴とする請求項１２に記載の光記録媒体である。
【００３３】
請求項１４の発明は、前記機能性色素は、記録再生用レーザの波長近傍に最大屈折率を持つように波長制御した色素であることを特徴とする請求項１２に記載の光記録媒体である。
【００３４】
請求項１３または１４の構成によれば、レーザ光の発振波長近傍に最大吸収波長または最大屈折率を持つ機能性色素を用いることによって、記録層の光学特性変化を検知することにより光記録媒体の記録再生を行う場合に、最もコントラストが得られる条件に合致させることができる。
【００３５】
請求項１５の発明は、前記機能性色素は、フォトクロミック色素であることを特徴とする請求項１２〜１４のいずれかに記載の光記録媒体である。
【００３６】
請求項１５の構成によれば、記録層の書き換えが可能な記録媒体を得ることが可能である。
【００３７】
【発明の実施の形態】
以下、本発明の実施の形態について説明する。
前述のように本発明の有機機能薄膜は、互いに非相溶であるポリマー鎖が結合したブロック共重合体により形成されたミクロ相分離構造を有しており、そのミクロ相分離構造の一方の分離相を形成するポリマー鎖には、最初、脱離可能な置換基が結合しており、薄膜化した後に置換基を脱離して空孔を形成し、この空孔に機能性色素を含有した構造からなる。なお、置換基は、酸触媒により脱離されるものであることが好ましい。
【００３８】
この有機機能薄膜の特長は、機能性色素がナノメータサイズで、しかも高度に秩序化されて高分子マトリックスの空孔に含有されていることである。その秩序化されたナノメータサイズ構造の形成における原動力（ドライビングフォース）として、ブロック共重合体のミクロ相分離現象を利用するものである。
ミクロ相分離構造としては、球状構造（海島構造）、柱状構造、ラメラ状構造、共連続状構造、もしくはその類似構造が利用できる。
図１に本発明における機能性色素が含有される一方の分離相の代表的なミクロ相分離構造の模式図を示す。
このように一方の分離相（高分子マトリックス）に空孔を形成し、この空孔にナノメータサイズの機能性色素を導入し、三次元的に高度に構造制御して複合化することにより、光学的性質、電子的性質、導電的性質等の新たな機能が発現する有機機能薄膜が作製することができる。なお、有機機能薄膜を光記録媒体に適用する場合には、機能性色素としては、光または熱により、その光学特性を変化させる機能を有する色素からなることが好ましい。
【００３９】
本発明の有機機能薄膜におけるミクロ相分離構造の一方の分離相を形成するポリマー鎖に結合し、例えば、酸触媒により脱離可能な置換基は、脱離した後に気化することが好ましく、脱離した置換基の沸点は、ブロック共重合体のガラス転移点（Ｔｇ）以下であることが好ましい。すなわち、本発明においては、ミクロ相分離構造を形成した後に酸触媒によって置換基の脱離反応を進行させるために、更に加熱を必要とする。したがって、その際ミクロ相分離構造を壊さないためにはブロック共重合体のＴｇ以下の温度で加熱（できるだけ短時間に）することが好ましいためである。
【００４０】
更に、脱離した置換基が気化することにより、ミクロ相分離したブロック共重合体中に空孔ができ、その空孔に機能性色素を効率よく導入する（埋め込む）ことができる。
置換基としては、ブロック共重合体のＴｇ以下で脱離するものであれば、特に制約はないが、好ましい置換基の構造としては、例えば、下記構造式（I）あるいは構造式（II）で示される基が挙げられる。
【００４１】
【化３】

【００４２】
本発明におけるブロック共重合体は、互いに非相溶である各ポリマーを組み合わせて合成することができる。２種以上のポリマーの組合せであってもよい。
本発明に用いるブロック共重合体の合成法としては、例えば、スチレン、イソプレン、α−メチルスチレン、クロロメチルスチレン、２ビニルピリジン、アミノスチレン、４−ビニルピリジン、メタクリレート類、ε−カプロラクトン、ブタジエン、ビニルメチルエーテル、１、３−シクロヘキサンジエン、エチレンオキシドや、酸触媒により脱離可能な基で保護されたビニルフェノールやアクリル酸、メタクリル酸等の各種モノマーを用いて得られる、当該互いに非相溶のポリマー鎖の末端から重合するリビング重合法（アニオン重合、リビングラジカル重合）、あるいは鎖の中央から合成するリビング重合（アニオン重合）、または末端官能性ポリマーの末端を結合させる合成法（アニオン重合、リビングラジカル重合等）などの重合方法によって合成することができる。
例えば、リビングラジカル重合法によって、酸触媒により脱離する置換基を有するポリスチレンと、ポリメチルメタクリレートとのブロック共重合体、あるいはポリスチレンと、酸触媒により脱離する置換基を有するポリメタクリル酸とのブロック共重合体が合成できる。
【００４３】
本発明において好ましく用いられる酸触媒としては、所望のポリマー鎖に結合した置換基を脱離することができるものであり、空孔形成を阻害せず、またミクロ相分離構造を壊すものでなければ、特に制約はなく使用することができる。このような酸触媒としては、酸化合物、あるいは光照射もしくは加熱により酸化合物を発生する化合物（光酸発生剤、熱酸発生剤）を用いることができる。
酸化合物としては、例えば、ｐ−トルエンスルホン酸等の公知の化合物を用いることができる。また、酸化合物を発生する化合物としては、例えば、トリフェニルスルホニウムトリフレート等のスルホニウム化合物、ジフェニルヨードニウムトリフレート等のヨードニウム化合物、あるいはニトロベンジルエステル化合物等いずれも公知の化合物を用いることができる。
上記酸触媒は、適用対象物や、それに応用する有機機能薄膜の製造工程などに応じて適宜選択される。
【００４４】
また、本発明の有機機能薄膜に用いられる機能性色素としては、レーザの照射エネルギーにより、ヒートモード（熱分解等）でその光学定数を変化させる化合物、あるいは、レーザの照射エネルギーによりフォトンモードでその光学定数を変化させる化合物がある。
レーザの照射エネルギーによりヒートモード（熱分解等）でその光学定数を変化させる化合物としては、例えば、ポリメチン色素、スクアリリウム系、ピリリウム系、ポルフィリン系、ポルフィラジン系、アゾ系、アゾメチン系染料等、あるいはそれらの金属錯体化合物が挙げられる。
更に、レーザの照射エネルギーによりフォトンモードでその光学定数を変化させる化合物としては、例えば、フルギド類、ジアリールエテン類、アゾベンゼン類、スピロピラン類、スチルベン類、ジヒドロピレン類、チオインジゴ類、ビピリジン類、アジリジン類、芳香族多環類、アリチリデンアニリン類、キサンテン類等のフォトクロミック材料が挙げられる。
【００４５】
上記化合物において、記録の書き換えが可能なフォトクロミック材料は、特に好ましい。また、上記の化合物を単独で用いてもよいし、２種以上の組合せにして用いてもよい。
更に、上記化合物に加えて、特性改良等の目的で、安定剤（例えば遷移金属錯体）、紫外線吸収材、分散剤、難燃剤、滑剤、帯電防止剤、界面活性剤、可塑剤などと一緒に用いることもできる。
なお、有機機能薄膜の空孔に導入された機能性色素のドット径は、５ｎｍ〜５００ｎｍ、好ましくは１０ｎｍ〜２００ｎｍが適当である。
【００４６】
次に、本発明の有機機能薄膜の製造方法について説明する。
本発明における有機機能薄膜は以下のような製造方法によって製造することができる。なお、各製造方法においてミクロ相分離を促進させるために、ブロック共重合体以外に他のポリマーを添加しても構わない。
【００４７】
第一の方法は、まず、互いに非相溶であるポリマー鎖が結合したブロック共重合体を含有する溶液を調製した後、浸漬塗布法やスピンコート法等により薄膜化して、溶媒キャストもしくは温度変化によりミクロ相分離構造を形成し（ミクロ相分離構造を有する有機薄膜を形成する工程）、次に、その有機薄膜に酸を接触させ（有機薄膜に酸を接触させる工程）、これを加熱して酸触媒反応によりポリマー鎖に結合した脱離可能な置換基を取り除き（空孔を形成する工程）、置換基脱離によって形成されたナノメータサイズの空孔に機能性色素を導入する（空孔に機能性色素を含有させる工程）ことにより、本発明の秩序化された構造の有機機能薄膜を得る製造方法である。
【００４８】
第二の方法は、まず、互いに非相溶であるポリマー鎖が結合したブロック共重合体を含有する溶液を調製した後、浸漬塗布法やスピンコート法等により薄膜化して、溶媒キャストもしくは温度変化によりミクロ相分離構造を形成し（ミクロ相分離構造を有する有機薄膜を形成する工程）、次に、その有機薄膜に光酸発生剤を接触させ（有機薄膜に光酸発生剤を接触させる工程）、更に光照射をした後に加熱して酸触媒反応によりポリマー鎖に結合した脱離可能な置換基を取り除き（空孔を形成する工程）、置換基脱離によって形成されたナノメータサイズの空孔に機能性色素を導入する（空孔に機能性色素を含有させる工程）ことにより、本発明の秩序化された構造の有機機能薄膜を得る製造方法である。
【００４９】
第三の方法は、まず、互いに非相溶であるポリマー鎖が結合したブロック共重合体と、前記脱離可能な置換基を有するポリマー鎖が形成する分離相にのみ相溶性のある光酸発生剤とを含有する溶液を調製した後、浸漬塗布法やスピンコート法等により薄膜化して、溶媒キャストもしくは温度変化によりミクロ相分離構造を形成し（ミクロ相分離構造を有する有機薄膜を形成する工程）、次に、該有機薄膜に光照射をした後に加熱して酸触媒反応によりポリマー鎖に結合した脱離可能な置換基を取り除き（空孔を形成する工程）、置換基脱離によって形成されたナノメータサイズの空孔に機能性色素を導入する（空孔に機能性色素を含有させる工程）ことにより、本発明の秩序化された構造の有機機能薄膜を得る製造方法である。
なお、光酸発生剤としては、前記のような公知の化合物が使用できる。
【００５０】
第四の方法は、まず、互いに非相溶であるポリマー鎖が結合したブロック共重合体を含有する溶液を調製した後、浸漬塗布法やスピンコート法等により薄膜化して、溶媒キャストもしくは温度変化によりミクロ相分離構造を形成し（ミクロ相分離構造を有する有機薄膜を形成する工程）、次に、その有機薄膜に熱酸発生剤を接触させ（有機薄膜に熱酸発生剤を接触させる工程）、更に加熱して酸触媒反応によりポリマー鎖に結合した脱離可能な置換基を取り除き（空孔を形成する工程）、置換基脱離によって形成されたナノメータサイズの空孔に機能性色素を導入する（空孔に機能性色素を含有させる工程）ことにより、本発明の秩序化された構造の有機機能薄膜を得る製造方法である。
なお、熱酸発生剤としては、前記のような公知の化合物が使用できる。
【００５１】
４つのいずれかの方法により形成した有機薄膜の空孔に機能性色素を導入する方法としては、例えば、空孔が形成された有機薄膜と機能性色素溶液（機能性色素を溶媒に溶解または分散）とを浸漬や塗布などにより接触させて行う湿式法により有機薄膜の空孔に導入（埋め込む）することができる。なお、有機薄膜への機能性色素の導入方法は、これに限定されるものではなく、目的とする適用対象物やその素材、形態、あるいは製造工程などに応じて好適な方法が適宜選択される。
【００５２】
次に、前記有機機能薄膜を、記録材料（記録層）として応用した光記録媒体について説明する。
従来の光記録媒体は、連続した記録材料から構成された記録層（記録材料が存在する層）を備えており、この記録層にレーザビームを照射し、レーザビームの形状に相応した何らかの変化（光学的な変化を伴う物理的、化学的等の変化）を記録材料に対して形成して記録するものである。したがって、最小記録ピットのサイズは、光学系の発振波長とレンズのＮＡで決定されるレーザビーム径に依存するため、従来の記録再生システムでは、高密度化は基本的にレーザの発振波長やレンズのＮＡの実用化技術力に左右されてきた。
また、ビーム形状がガウス分布した形状であることと、記録材料として熱または光に対し、明瞭なしきい値で変化する材料はほとんど存在ないこととから、形成されるピットの最外周の大きさや変化量は均一とはならず、その再生信号品質にもバラツク要因が必ず存在し、高品質の信号特性を得るにも限界があった。
【００５３】
本発明の記録媒体は、上記の従来記録媒体の課題を克服した新しい構造の光記録媒体である。すなわち、本発明の有機機能薄膜を応用した光記録媒体は、連続した層中に、機能性色素が形成するナノメータサイズの記録層ドットがマトリックスを介して高度に秩序化され、非連続して存在する構造である。この記録層ドットのサイズは、１０〜５００ｎｍであり、均一に形成されている。
したがって、このような予め形成されたナノメータサイズの記録層ドットを利用することにより、レーザ発振波長やレンズのＮＡで決定されることなく、最小記録ピットのサイズは、形成する記録層ドットのみで決定されるため、任意の記録密度の記録媒体が設計可能となる。更に、記録ピットの最外周のエッジもこの有機機能薄膜の構造体で決定されているため、この記録層ドット全体を変化させるように記録することで、ピットのバラツキのない、高品質の信号特性を得ることが可能となる。
【００５４】
本発明の光記録媒体の構成及びその必要物性について以下に説明する。
〈記録媒体構成〉
本発明の光記録媒体は、基板上に前記有機機能薄膜からなる記録層を設けるものであるが、その他必要により構成層として、下引き層、金属反射層、保護層、基板面ハードコート層などを設けることができ、目的や要求特性に応じて構成層の形態が選ばれる。本発明の光記録媒体について図面を参考にして説明する。
本発明の光記録媒体は、例えば図２（ａ）〜（ｄ）や図３（ａ）〜（ｅ）の概略断面図に示す例のような構成を有するものである。すなわち、図２（ａ）〜（ｄ）の場合には、基板上に金属反射層を設けずに構成した例を示す。また、図３（ａ）〜（ｅ）の場合には、金属反射層を設けて構成した例を示す。
本発明の光記録媒体の構成としては、追記型光ディスクの構造(基板上に記録層を設けたものを２枚貼り合わせたいわゆるエアーサンドイッチ構造)としてもよく、ＣＤ−Ｒ構造（基板上に記録層、反射層、保護層を設ける）としてもよく、ＣＤ−Ｒ構造を貼り合わせたＤＶＤ構造でもよい。なお、上記構成は実施の形態を説明するための例であって他の構成でもよい。以下に光記録媒体の各構成層について説明する。
【００５５】
〈基板〉
本発明の光記録媒体に用いる基板としては、基板側より記録再生を行なう場合のみ使用レーザーに対して透明でなければならず、記録層側（基板と反対側）から記録、再生を行なう場合には基板は透明である必要はない。
基板材料としては、例えば、ポリエステル、アクリル樹脂、ポリアミド、ポリカーボネート樹脂、ポリオレフィン樹脂、フェノール樹脂、エポキシ樹脂、ポリイミドなどのプラスチック、またはガラス、セラミック、あるいは金属などを用いることができる。なお、基板の表面にトラッキング用の案内溝や、案内ピット、更にアドレス信号などのプリフォーマットなどが形成されていてもよい。
【００５６】
〈記録層〉
記録層は、レーザ光の照射により何らかの変化（光学特性の変化または形状の変化）を生じさせ、その変化により情報を記録し、光学的に再生可能なものであって、その記録層は、前記のように互いに非相溶であるポリマー鎖が結合したブロック共重合体により形成されたミクロ相分離構造を有し、該ミクロ相分離構造の一方の分離相を形成するポリマー鎖は、脱離可能な置換基（例えば、酸触媒により脱離する置換基）を有し、該置換基の脱離によって形成された空孔に機能性色素を含有する構成からなる。
機能性色素の光学特性としては、記録再生用レーザ波長に対し、その吸収特性変化を利用して再生する場合には、レーザ波長近傍に最大吸収波長を持つように波長制御することが好ましく、記録再生用レーザ波長に対し、その屈折率変化を利用して再生する場合には、レーザ波長近傍に最大屈折率を持つように波長制御することが好ましい。
【００５７】
また再生法としてレーザ照射により蛍光特性に変化を与えその変化を再生する方法は、僅かな変化でも高コントラストに再生が可能であり、本光記録媒体のような記録ピットの大きさ（ドット列化されたナノメーターサイズの大きさ）が予め決まっている場合には、特に従来法に比較して大幅な低エネルギーで記録することが可能となる。
従来法（光源サイドからの手法）の場合には、十分な照射エネルギーを付与して記録しなければ明瞭なピット形状の形成ができなかった。このため、レーザ照射よる記録材の反応率が高くなければ記録ができなかった。一方、ピットが予め形成されている本記録媒体では、僅かな反応率でも再生が可能であり、特に蛍光再生においては特に有効である。
【００５８】
〈下引き層〉
下引き層は、（１）接着性の向上、（２）水またはガスなどのバリアー、（３）記録層の保存安定性の向上、（４）反射率の向上、（５）溶剤からの基板の保護、（６）案内溝、案内ピット、プレフォーマットの形成などを目的として使用される。
（１）の目的に対しては、高分子材料、例えば、アイオノマー樹脂、ポリアミド樹脂、ビニル樹脂、天然樹脂、天然高分子、シリコーン、液状ゴムなどの種々の高分子化合物及び、シランカップリング剤などを用いることができる。
（２）あるいは（３）の目的に対しては、上記高分子材料以外に無機化合物、例えば、ＳｉＯ、ＭｇＦ、ＳｉＯ₂、ＴｉＯ、ＺｎＯ、ＴｉＮ、ＳｉＮなどがあり、更に金属あるいは半金属、例えば、Ｚｎ、Ｃｕ、Ｎｉ、Ｃｒ、Ｇｅ、Ｓｅ、Ａｕ、Ａｇ、Ａｌ、などを用いることができる。
（４）の目的に対しては、金属、例えば、Ａｌ、Ａｕ、Ａｇ等や、金属光沢を有する有機薄膜、例えば、メチン染料、キサンテン系染料などを用いることができる。
（５）あるいは（６）の目的に対しては、紫外線硬化樹脂、熱硬化樹脂、熱可塑性樹脂等を用いることができる。
上記下引き層の膜厚としては０．０１〜３０μｍ、好ましくは、０．０５〜１０μｍが適当である。
【００５９】
〈金属反射層〉
金属反射層は、要求される反射率に応じて必要な場合用いられる。
反射層としては、単体で高反射率が得られる腐食されにくい金属あるいは半金属等が用いられ、このような材料例としては、Ａｕ、Ａｇ、Ｃｒ、Ｎｉ、Ａｌ、Ｆｅ、Ｓｎなどが挙げられる。これら材料の中で、反射率、生産性の点からＡｕ、Ａｇ、Ａｌが最も好ましい。これらの金属、半金属は、単独で使用してもよく、２種の合金としてもよい。
反射層の膜形成法としては、限定するものではないが、蒸着、スッパタリングなどが挙げられる。反射層の膜厚としては、５０〜５０００Åが好ましく、更には１００〜３０００Åが好ましい。
【００６０】
〈保護層、基板面ハードコート層〉
保護層及び基板面ハードコート層は、（１）記録層(反射吸収層)を傷、ホコリ、汚れ等から保護する、（２）記録層(反射吸収層)の保存安定性の向上、（３）反射率の向上等を目的として使用される。これらの目的に対しては、前記下引き層に示した材料を用いることができる。
また、無機材料として、ＳｉＯ、ＳｉＯ₂なども用いることができ、有機材料としてポリメチルアクリレート、ポリカーボネート、エポキシ樹脂、ポリスチレン、ポリエステル樹脂、ビニル樹脂、セルロース、脂肪族炭化水素樹脂、天然ゴム、スチレンブタジエン樹脂、クロロプレンゴム、ワックス、アルキッド樹脂、乾性油、ロジン等の熱軟化性、熱溶融性樹脂も用いることができる。
上記材料のうち最も好ましい例としては、生産性に優れた紫外線硬化樹脂である。保護層または基板面ハードコート層の膜厚は、０．０１〜３０μｍ、好ましくは０．０５〜１０μｍが適当である。
本発明において、前記下引き層、保護層及び基板面ハードコート層には、記録層の場合と同様に、安定剤、分散剤、難燃剤、滑剤、帯電防止剤、界面活性剤、可塑剤等を含有させることができる。
【００６１】
【実施例】
以下、実施例により本発明を更に詳細に説明する。ただし、本発明はなんら実施例に限定されるものではない。
実施例１〜３：有機薄膜に係る実施例
数平均分子量約５０，０００のポリ（ｐ−ｔｅｒｔ−ブトキシカルボニルオキシスチレン）（ＰＢＯＣＳＴ）とポリメチルメタクリレート（ＰＭＭＡ）とからなり、ＰＢＯＣＳＴの体積分率がそれぞれ１６ｖｏｌ％（実施例１）、３３ｖｏｌ％（実施例２）、５２ｖｏｌ％（実施例３）であるブロック共重合体をリビングラジカル法で合成した。
得られた実施例１〜実施例３の体積分率からなるブロック共重合体をシクロヘキサノンに溶解し、マイカ上にキャスト膜（有機薄膜）を形成した。更に、このキャスト膜を１４０℃で８時間加熱処理してその相分離構造を小角Ｘ線散乱方法（ＳＡＸＳ）測定、透過型電子顕微鏡（ＴＥＭ）観察により調べた。その結果、各実施例における相分離構造は、それぞれ数十ｎｍ以下の球状構造（実施例１）、柱状構造（実施例２）、及びラメラ構造（実施例３）であることが確認された。
次に作製した各実施例のキャスト膜をｐ−トルエンスルホン酸の１ｗｔ％イソプロピルアルコール溶液に浸漬させた後に、９０℃で５分間加熱処理を行った。そのキャスト膜を原子間力顕微鏡（ＡＦＭ）により観察したところ、いずれの実施例の場合にもブロック共重合体のＰＢＯＣＳＴ構造部であるポリマー鎖の部分に空孔が形成されていていることが確認された（この空孔が形成されている部分は、置換基が脱離し、ポリ−ｐ−ヒドロキシスチレン（ＰＨＳ）に変化した箇所に相当する）。
更に、空孔が形成された各実施例のキャスト膜を、tris（p-dimethylaminophenyl）methylium SbF₆の０．５ｗｔ％メタノール／ピリジン（：２０／１）溶液の中に浸漬させた。このキャスト膜の表面層をＴＥＭにより観察した結果、いずれも、色素がＰＨＳ部分に偏析しており、空孔に色素が含有された秩序化された構造が形成されていることが確認された。
【００６２】
実施例４
数平均分子量約７０，０００のポリスチレン（ＰＳＴ）とポリ−ｔｅｒｔ−ブチルメタクリレート（ＰｔＢＭＡ）とからなり、ＰｔＢＭＡの体積分率が２８ｖｏｌ％となるブロック共重合体をリビングラジカル法で合成した。
得られたブロック共重合体とトリフェニルスルホニウムトリフレートとを１００：３となるようにシクロヘキサノンに溶解し、マイカ上にキャスト膜（有機薄膜）を形成した。
得られたキャスト膜を１４０℃で１０時間加熱処理してその相分離構造をＳＡＸＳ測定、ＴＥＭ観察により調べた。その結果、相分離構造は、数十ｎｍ以下のの柱状構造であることが確認された。
更に、上記相分離構造を有するキャスト膜に光照射を行い、その後に１００℃で３分間加熱し、ＡＦＭにより観察を行ったところ、ブロック共重合体のＰｔＢＭＡ構造部であるポリマー鎖の部分に空孔が形成されていていることが確認された（この空孔が形成されている部分は、置換基が脱離し、ポリメタクリル酸（ＰＭＡＡ）に変化した箇所に相当する）。
更に、空孔が形成されたキャスト膜に、3,3,3',3'-tetramethyl-1,1'-bis(3-sulfoethyl)-2,2'-indodicarbocyanine hydroxide triethylamine saltの１ｗｔ％水溶液を滴下し、乾燥した。このキャスト膜の表面層をＴＥＭにより観察した結果、色素が柱状構造（ＰＭＡＡ部分）に偏析しており、空孔に色素が含有された秩序化された構造が形成されていることが確認された。
【００６３】
比較例１
実施例４において用いた酸触媒のトリフェニルスルホニウムトリフレートに代えて、ｐ−トルエンスルホン酸を用いたところ、柱状構造は確認されたが、空孔は確認されなかった。
【００６４】
上記実施例１〜４の結果から、ブロック共重合体に球状、柱状、ラメラ状の相分離構造が形成され、その分離相に置換基の脱離に基づく秩序化されたナノメータサイズの空孔を生じさせ、形成された空孔に選択的に機能性色素を含有させた有機機能薄膜を作製することがきた。この有機機能薄膜の有する機能性色素の機能と高度に秩序化された構造により、有用で新規な性質（光学的性質、電子的性質、導電的性質等）が発現する。
なお、前記のように比較例１の場合には、空孔は確認されなかったが、この理由は、ミクロ相分離構造を構築するために加熱する際に脱離基も一緒に外れてしまい、そのために最初からＰＳＴとＰＭＡＡとのブロック共重合となってしまい、後の空孔形成時において空孔ができない（隙間が生じない形になってしまう）状態になったためであると考えられる。
【００６５】
実施例５：記録体に係る実施例
実施例３で合成したブロック共重合体のシクロヘキサノン溶液を、厚さ１ｍｍ、５ｃｍ四方の石英基板上にスピンコートした。ただし、スピンコートは溶媒が均一に広がったところで回転を停止した。
次に、ブロック共重合体溶液をスピンコートした石英基板を乾燥し、更に１３０℃で５時間加熱処理を行った。このようにして得られた有機薄膜の相分離構造をＴＥＭにより観察してラメラ構造であることを確認した後に、ｐ−トルエンスルホン酸の１ｗｔ％メタノール溶液を滴下し、１００℃で３分間加熱した。更に、実施例３と同様に色素溶液に浸漬し、色素をＰＨＳからなるラメラ構造内に導入し（埋め込み）、記録体とした。
この記録体に発振波長６３５ｎｍ、ビーム径１μｍの半導体レーザ光を水平方向に１．５μｍ間隔で１．０ｃｍ²スキャンさせた。この照射部および未照射部をＴＥＭ、及び光学顕微鏡による観察、顕微分光法による反射率及び透過率の測定、蛍光観察を行った。結果を下記表１に示す。
【００６６】
比較例２
色素溶液に浸漬しないこと以外は実施例５と同様にして記録体を作製し、記録を行って、照射部および未照射部をＴＥＭ、及び光学顕微鏡による観察、顕微分光法による反射率及び透過率の測定、蛍光観察を行った。結果を下記表１に示す。
【００６７】
【表１】

【００６８】
評価結果
実施例と比較例の結果から、本発明に係る実施例５の記録体の有機薄膜は、レーザ光照射により、ＰＨＳ内に埋め込まれた色素に記録がなされたことが確認され、記録可能なことが明らかになった。
なお、本実験では、色素ドット径（数十ｎｍ）に比較して、径の大きなビーム（１μｍ）光源を用いて記録したため、記録体に形成されたナノメータサイズの多数の色素ドットを一度に記録したが、色素ドットと同程度のビーム径で記録すれば、色素ドットを個別に記録することが可能であることが判明した。
また、記録信号が反射率変化として再生できることから、この現象を利用して再生する方式では、記録再生用レーザの発振波長近傍に、機能性色素の最大吸収波長を制御するか、あるいは機能性色素の最大屈折率を制御することが最も好ましいことが分かった。
更に、記録信号が蛍光の有無として再生でき、しかも上記透過率や反射率に比較し大きなＳ／Ｎ比で再生が可能で、本方式の光記録媒体の再生法としては特に好ましいことが認められた。
【００６９】
【発明の効果】
本発明は、互いに非相溶であるポリマー鎖が結合したブロック共重合体を用いて形成したミクロ相分離構造の一方の分離相を構成するポリマー鎖に、脱離可能な置換基を結合し、この置換基を脱離してナノメータサイズの秩序ある空孔を形成し、この空孔に機能性色素を導入して複合化することにより、光学的性質、電子的性質、導電的性質等の新たな機能を発揮する有機機能薄膜の提供を可能とする。なお、置換基は、酸触媒により脱離するような基であるのが好ましい。
特に、ナノメータサイズの機能性色素から構成される秩序化されたドット構造（ドット列）を有する有機機能薄膜を記録材料（記録層）として用いることにより、照射されるレーザ光の発振波長やレンズのＮＡに依存することなく、レーザピックアップの回折限界を超える記録密度で記録再生が可能な光記録媒体を提供することができる。
また、上記有機機能薄膜は、少なくとも、ブロック共重合体ミクロ相分離構造を有する有機薄膜を形成する工程と、酸触媒反応によりポリマー鎖に結合した脱離可能な置換基を取り除き空孔を形成する工程と、空孔に機能性色素を含有させる工程とを含む製造工程により製造することができ、これによって構造制御して複合化した有機機能薄膜の提供を可能とする。
【図面の簡単な説明】
【図１】本発明の有機機能薄膜における機能性色素が含有される一方の分離相のミクロ相分離構造((a)球状構造、(b)柱状構造、(c)ラメラ状構造)を示す模式図である。
【図２】本発明の有機機能薄膜を記録層に設けた光記録媒体の金属反射層を備えない場合の層構成例（ａ）〜（ｄ）を示す概略断面図である。
【図３】本発明の有機機能薄膜を記録層に設けた光記録媒体の金属反射層を備えた場合の層構成例（ａ）〜（ｅ）を示す概略断面図である。
【符号の説明】
１ 基板
２ 記録層
３ 下引き層
４ 保護層
５ 基板面ハードコート層
６ 金属反射層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an organic functional thin film having high functionality that can be applied as an electronic material or an optical material used in the fields of optical disks, optical cards, optical tapes, and the like, and an optical recording medium using the organic functional thin film. The organic functional thin film useful for optical recording media that records and reproduces information by causing optical changes such as the transmittance and reflectance of the recording material, and ultrahigh-density optical recording using the same It relates to the medium.
[0002]
[Prior art]
It is expected that new functions such as electronic properties, conductive properties, optical properties, magnetic properties, etc. will be exhibited by introducing nanometer-sized functional materials into polymer materials and compositing them. Therefore, the compounding of nanometer-sized materials has attracted attention as an important technique for obtaining functional composite materials.
As such a functional material, research and development of a metal-organic composite material composed of nanometer-sized metal ultrafine particles, that is, metal nanoclusters, is being promoted.
For example, a composite in which ultrafine metal particles are contained in the vicinity of the center in one phase in a microphase separation structure of an incompatible block copolymer, that is, a metal / organic polymer (Mn1) composite and a matrix polymer (Mn2) ), A phase separation structure is formed by solvent casting or temperature operation (Mn1> Mn2), and then a polymer phase not containing metal fine particles is removed (see, for example, Patent Document 1). ).
Also proposed is a metal / organic polymer composite structure in which ultrafine particles of metal are contained in a row in one polymer phase of a microphase separation structure of a block copolymer bonded to each end of incompatible polymer chains. Has been. The ultrafine metal particles in this composite structure are composed of a block copolymer in which a polymer chain having an affinity for a metal compound and a polymer chain having an affinity for a metal compound are bonded at the end, and a high boiling point capable of reducing metal ions. There has been proposed a method of dissolving in a solvent and a low-boiling solvent, removing the low-boiling solvent to form a phase separation structure, and reducing and forming metal ions while removing the high-boiling solvent (see, for example, Patent Document 2). .)
Patent Document 1 and Patent Document 2 all relate to a metal / organic polymer composite structure (porous body) intended to be used as a catalyst, an immobilized catalyst, a membrane reactor, an antistatic plastic or the like.
[0003]
As another form of research, a resin layer containing a copolymerized polymer is formed on a substrate, and a predetermined region is irradiated with infrared rays, visible rays, ultraviolet rays, or ionizing radiation, and then subjected to a thermal annealing treatment. A method of forming a separation structure and forming a nanopattern by etching has been proposed (for example, see Patent Document 3).
Alternatively, a molded body containing a block polymer or graft copolymer having a salt-forming group (acidic group or basic group) is formed, and the salt-forming group of the formed molded body is changed to a salt, and then a micro separation structure is formed. A method of forming a pattern has been proposed (see, for example, Patent Document 4).
The above Patent Document 3 and Patent Document 4 are both intended to form a nano-order pattern to be applied to an electronic component by utilizing a microphase separation structure in lithography technology.
[0004]
As described above, research using the microphase separation structure has already been carried out, but it contains a functional dye introduced by controlling the desired (arbitrary) separation phase of the microphase separation structure to maintain an ordered structure. At present, the research and development of organic functional thin films, especially recording media, has hardly been promoted.
[0005]
On the other hand, in the optical memory field, so-called recordable CD-R and DVD-R corresponding to the CD standard and the DVD standard are currently commercialized as optical recording media having a reflective layer on a substrate. As the amount of information increases, higher recording capacity and smaller size are required. For this reason, further improvement in the recording density of such an optical recording medium is desired.
Elemental techniques for improving the recording capacity in the current optical recording system include a recording pit miniaturization technique and an image compression technique represented by MPEG2. In order to reduce the recording / reproducing light wavelength and increase the diffraction limit, the recording pit miniaturization technology has been studied to increase the numerical aperture (NA) of the optical system. Regeneration is impossible. For this reason, super-resolution technology capable of recording and reproducing beyond the diffraction limit and optical memory systems using near-field light have attracted attention as promising means, but they have not yet been put into practical use due to the high technical hurdles. .
[0006]
In view of the above situation, there is a need for the development of a more realistic new technology that enables higher-density recording by minute recording exceeding the diffraction limit.
[0007]
[Patent Document 1]
JP 2000-72951 A
[Patent Document 2]
JP 2000-72952 A
[Patent Document 3]
JP 2002-287377 A
[Patent Document 4]
JP 2002-241532 A
[0008]
[Problems to be solved by the invention]
The present invention has been made in view of the above-described problems. As described later, the organic functional thin film is used to enable high-density recording by a method completely different from the conventional approach from the light source side. It is what. That is, the present invention relates to a novel organic functional thin film constructed by incorporating a functional dye in an order of nanometer size into a polymer chain of an arbitrary separated phase in a microphase-separated structure formed in a block copolymer and its production In addition to providing a method, an object of the present invention is to provide an optical recording medium using the organic thin film as a recording material and capable of recording and reproducing at a recording density exceeding the diffraction limit of a pickup lens.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, the present invention forms a microphase separation structure using a block copolymer in which polymer chains that are incompatible with each other are bonded, and one separated phase of the microphase separation structure is formed. A detachable substituent is bonded to the polymer chain in advance, and by removing this substituent, a nanometer-size vacancy is formed, and this vacancy is functional while maintaining an ordered structure. By introducing a dye into a composite, it is possible to provide a functional composite material (organic functional thin film) that exhibits new functions such as optical properties, electronic properties, and conductive properties. The present invention also provides a method for producing an organic functional thin film by such compounding and an optical recording medium using the organic functional thin film. The substituent is preferably one that is eliminated by an acid catalyst.
Furthermore, by using the organic functional thin film of the present invention as a recording material (recording layer), the functional dye introduced into the pores is formed into a dot array with a small nanometer size. High density optical recording can be realized. That is, since the area of each dot formed on the recording layer itself is smaller than the diffraction limit of the irradiation light, an optical recording medium capable of recording and reproducing at a recording density exceeding the diffraction limit of the optical system (laser pickup) Can be obtained. Such a concept of the recording medium is completely different from the approach of increasing the density from the optical system in the prior art.
Hereinafter, the present invention will be specifically described.
[0010]
The invention of claim 1 has a microphase separation structure formed by a block copolymer in which polymer chains that are incompatible with each other are bonded, and the polymer chain forming one separated phase of the microphase separation structure is An organic functional thin film characterized by having a detachable substituent and containing a functional dye in pores formed by elimination of the substituent.
[0011]
According to the configuration of claim 1, a nanometer size highly ordered in a desired (arbitrary) separated phase in a microphase-separated structure formed in a block copolymer in which polymer chains that are incompatible with each other are bonded Thus, it is possible to introduce a functional dye into the pores while maintaining the ordered structure. Thus, it is possible to provide a functional composite material (organic functional thin film) that exhibits new functions such as optical properties, electronic properties, and conductive properties.
In particular, by using an organic functional thin film with an ordered dot structure (dot array) composed of nanometer-sized functional dyes as a recording material (recording layer), the recording density exceeds the diffraction limit of the laser pickup. An optical recording medium capable of recording and reproducing can be obtained.
[0012]
In the invention of claim 2, the microphase separation structure of the separated phase formed by the polymer chain having the detachable substituent is spherical, columnar, lamellar, co-continuous, or a structure similar to each of these shapes. It is an organic functional thin film of Claim 1 characterized by the above-mentioned.
[0013]
According to the configuration of claim 2, a functional composite material corresponding to the characteristic shape and form of each separated phase and the properties (optical properties, electronic properties, conductive properties, etc.) of the functional dye contained in the pores Can be provided. When the functional dye contained in the pores has a property that the optical properties are changed by light or heat, a recording material for a recording layer of an optical recording medium, particularly a recording material useful for high-density recording is provided.
[0014]
The organic functional thin film according to claim 1 or 2, wherein the boiling point of the substituent desorbed from the polymer chain is equal to or lower than the glass transition point (Tg) of the block copolymer. It is.
[0015]
According to the configuration of claim 3, the organic functional thin film has an ordered structure in which the microphase-separated structure is maintained without being broken, and uniform nanometer-sized vacancies are formed and a functional dye is introduced. Is obtained.
[0016]
The invention of claim 4 is characterized in that the substituent leaving from the polymer chain is a group represented by the following structural formula (I) or structural formula (II). It is an organic functional thin film of description.
[0017]
[Chemical 2]

[0018]
According to the configuration of claim 4, the desorbed substituent is easily vaporized, the microphase separation structure is not broken, and uniform nanometer-sized pores are formed. Thereby, an organic functional thin film having an ordered structure is obtained when a functional dye is introduced, and for example, a recording material useful for a recording layer of an optical recording medium, particularly for high-density recording is provided.
[0019]
The invention of claim 5 has a microphase separation structure formed by a block copolymer in which polymer chains that are incompatible with each other are bonded, and the polymer chain that forms one separated phase of the microphase separation structure A method for producing an organic functional thin film having a substituent detachable by an acid catalyst and containing a functional dye in pores formed by elimination of the substituent,
Preparing a solution containing the block copolymer, forming the thin film by coating the prepared solution to form an organic thin film having a microphase separation structure;
Contacting the organic thin film with an acid;
A step of forming a void by desorbing a substituent bonded to the polymer chain by an acid catalyst which is brought into contact with the organic thin film by heating;
Adding a functional dye to the pores;
It is a manufacturing method of the organic functional thin film characterized by including.
[0020]
The invention of claim 6 has a microphase separation structure formed by a block copolymer in which polymer chains that are incompatible with each other are bonded, and the polymer chain that forms one separated phase of the microphase separation structure has A method for producing an organic functional thin film having a substituent detachable by an acid catalyst and containing a functional dye in pores formed by elimination of the substituent,
Preparing a solution containing the block copolymer, forming the thin film by coating the prepared solution to form an organic thin film having a microphase separation structure;
Contacting the organic acid thin film with a photoacid generator;
A step of detaching a substituent bonded to the polymer chain to form vacancies with an acid generated from a photoacid generator heated and brought into contact with the organic thin film after light irradiation; and
Adding a functional dye to the pores;
It is a manufacturing method of the organic functional thin film characterized by including.
[0021]
The invention of claim 7 has a microphase separation structure formed by a block copolymer in which polymer chains that are incompatible with each other are bonded, and the polymer chain that forms one separated phase of the microphase separation structure A method for producing an organic functional thin film having a substituent detachable by an acid catalyst and containing a functional dye in pores formed by elimination of the substituent,
A solution containing the block copolymer and a photoacid generator that is compatible only with the separated phase formed by the polymer chain having the detachable substituent is prepared, and the prepared solution is applied to the coated thin film. Forming an organic thin film having a microphase separation structure,
A step of detaching a substituent bonded to the polymer chain to form vacancies with an acid generated from a photoacid generator contained by heating after irradiation of the organic thin film; and
Adding a functional dye to the pores;
It is a manufacturing method of the organic functional thin film characterized by including.
[0022]
The invention of claim 8 has a microphase separation structure formed by a block copolymer in which polymer chains that are incompatible with each other are bonded, and the polymer chain that forms one separated phase of the microphase separation structure has A method for producing an organic functional thin film having a substituent detachable by an acid catalyst and containing a functional dye in pores formed by elimination of the substituent,
Preparing a solution containing the block copolymer, forming the thin film by coating the prepared solution to form an organic thin film having a microphase separation structure;
Contacting the organic thin film with a thermal acid generator;
A step of releasing a substituent bonded to the polymer chain with an acid generated from a thermal acid generator that is brought into contact with heating of the organic thin film to form a void;
Adding a functional dye to the pores;
It is a manufacturing method of the organic functional thin film characterized by including.
[0023]
According to the production method of claims 5 to 8, the functional dye is a highly ordered structure in nanometer-sized vacancies formed in a desired separated phase in the microphase-separated structure of the block copolymer. It can be controlled to be contained selectively.
By complexing by controlling the structure in this way, it is possible to produce an organic functional thin film that exhibits new functions such as optical properties, electronic properties, and electroconductive properties. Further, it is possible to manufacture the optical recording medium of the present invention that can cope with ultra-high density recording.
[0024]
The invention according to claim 9 is the method for producing an organic functional thin film according to any one of claims 5 to 8, wherein the microphase separation structure is formed by solvent casting or temperature change.
[0025]
According to the structure of Claim 9, a micro phase-separation structure can be formed easily and the organic thin film provided with the structure and structure which should be provided as a precursor for forming an organic functional thin film is obtained.
[0026]
The invention according to claim 10 is characterized in that the step of incorporating a functional dye into the pores is performed by a wet method using a solvent. It is.
[0027]
According to the tenth aspect, since the prescription is selected according to the object to be applied, the combination of the materials, or the manufacturing process, the functional dye is controlled to have the ordered structure in the vacancies of the desired separated phase. Thus, it can be selectively contained. As a result, a dot array of nanometer size is realized, and for example, when used as a recording material, it becomes possible to manufacture the optical recording medium of the present invention that can cope with ultra-high density recording.
[0028]
The invention of claim 11 is an optical recording medium in which a recording layer comprising an organic functional thin film is provided on a substrate,
The organic functional thin film has a microphase separation structure formed by a block copolymer in which polymer chains that are incompatible with each other are bonded, and the polymer chain forming one separated phase of the microphase separation structure is removed. An optical recording medium having a separable substituent and containing a functional dye in pores formed by elimination of the substituent.
[0029]
According to the eleventh aspect, since the recording dots (recording dots) composed of the functional dye in the recording layer of the optical recording medium are uniformly formed with a nanometer size, ultrahigh density recording is possible. .
[0030]
The invention of claim 12 has a microphase separation structure formed by a block copolymer in which polymer chains that are incompatible with each other are bonded on a substrate, and forms one separated phase of the microphase separation structure. A polymer layer having a detachable substituent, and a recording layer made of an organic functional thin film containing a functional dye is provided in the pores formed by the elimination of the substituent, and irradiated with laser light to form the recording layer An optical recording medium which records and reproduces by changing the optical characteristics of a functional dye.
[0031]
According to the twelfth aspect, the recording dots in the recording layer of the optical recording medium are uniformly formed in the nanometer size, and the minute recording of the nanometer size can be performed without depending on the oscillation wavelength of the irradiated laser light or the NA of the lens. Realized and enables ultra-high density recording. Furthermore, it is possible to obtain excellent signal characteristics without obscure the outermost peripheral edge of the recording pit.
Furthermore, the outermost peripheral edge of the recording pit is recorded so as to change the entire recording layer dot of the organic thin film, so that the ambiguity of the outermost peripheral edge of the recording pit based on factors such as the Gaussian distribution of the conventional laser beam The above problem can be avoided, and it is possible to obtain high-quality signal characteristics without variations in recording pits.
[0032]
The invention according to claim 13 is the optical recording medium according to claim 12, wherein the functional dye is a dye whose wavelength is controlled so as to have a maximum absorption wavelength in the vicinity of the wavelength of the recording / reproducing laser. .
[0033]
The invention according to claim 14 is the optical recording medium according to claim 12, wherein the functional dye is a dye whose wavelength is controlled so as to have a maximum refractive index in the vicinity of the wavelength of the recording / reproducing laser. .
[0034]
According to the configuration of the thirteenth or fourteenth aspect, by using a functional dye having a maximum absorption wavelength or a maximum refractive index in the vicinity of the oscillation wavelength of the laser light, a change in the optical characteristics of the recording layer is detected, thereby detecting the optical recording medium. When performing recording and reproduction, it is possible to match the conditions for obtaining the highest contrast.
[0035]
The invention of claim 15 is the optical recording medium according to any one of claims 12 to 14, wherein the functional dye is a photochromic dye.
[0036]
According to the configuration of the fifteenth aspect, it is possible to obtain a recording medium in which the recording layer can be rewritten.
[0037]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
As described above, the organic functional thin film of the present invention has a microphase separation structure formed by a block copolymer in which polymer chains that are incompatible with each other are bonded, and one separation of the microphase separation structure. The polymer chain that forms the phase is bonded with a detachable substituent at first, and after forming a thin film, the substituent is removed to form a void, and a structure containing a functional dye in this void Consists of. The substituent is preferably one that is eliminated by an acid catalyst.
[0038]
The feature of this organic functional thin film is that the functional dye has a nanometer size and is highly ordered and contained in the pores of the polymer matrix. As a driving force (driving force) in the formation of the ordered nanometer size structure, the micro phase separation phenomenon of the block copolymer is used.
As the microphase separation structure, a spherical structure (sea-island structure), a columnar structure, a lamellar structure, a co-continuous structure, or a similar structure can be used.
FIG. 1 shows a schematic diagram of a typical microphase separation structure of one separated phase containing the functional dye in the present invention.
In this way, vacancies are formed in one separated phase (polymer matrix), nanometer-sized functional dyes are introduced into these vacancies, and the structure is complexed by highly controlling the structure in three dimensions. It is possible to produce an organic functional thin film that exhibits new functions such as mechanical properties, electronic properties, and conductive properties. When the organic functional thin film is applied to an optical recording medium, the functional dye is preferably made of a dye having a function of changing its optical characteristics by light or heat.
[0039]
In the organic functional thin film of the present invention, a substituent that binds to a polymer chain forming one separated phase of the microphase-separated structure and can be removed by an acid catalyst, for example, is preferably vaporized after being removed. The boiling point of the substituted group is preferably not more than the glass transition point (Tg) of the block copolymer. That is, in the present invention, further heating is required to advance the elimination reaction of the substituent by the acid catalyst after forming the microphase separation structure. Therefore, in this case, in order not to break the microphase-separated structure, it is preferable to heat (in as short a time as possible) at a temperature not higher than Tg of the block copolymer.
[0040]
Further, when the detached substituent is vaporized, vacancies are formed in the microphase-separated block copolymer, and the functional dye can be efficiently introduced (embedded) into the vacancies.
The substituent is not particularly limited as long as it is eliminated at Tg or less of the block copolymer, but preferred substituent structures include, for example, the following structural formula (I) or structural formula (II): And the groups shown.
[0041]
[Chemical 3]

[0042]
The block copolymer in the present invention can be synthesized by combining polymers that are incompatible with each other. It may be a combination of two or more polymers.
Examples of the method for synthesizing the block copolymer used in the present invention include styrene, isoprene, α-methylstyrene, chloromethylstyrene, 2 vinylpyridine, aminostyrene, 4-vinylpyridine, methacrylates, ε-caprolactone, butadiene, Vinyl methyl ether, 1,3-cyclohexanediene, ethylene oxide, and incompatible with each other obtained by using various monomers such as vinyl phenol, acrylic acid, and methacrylic acid protected with a group removable by an acid catalyst. Living polymerization method (anionic polymerization, living radical polymerization) that polymerizes from the end of the polymer chain, or living polymerization method (anionic polymerization) that is synthesized from the center of the chain, or a synthetic method that bonds the end of the terminal functional polymer (anionic polymerization, living) Polymerization methods such as radical polymerization) Can be synthesized.
For example, by a living radical polymerization method, a block copolymer of polystyrene having a substituent that is eliminated by an acid catalyst and polymethyl methacrylate, or polystyrene and polymethacrylic acid having a substituent that is eliminated by an acid catalyst. A block copolymer can be synthesized.
[0043]
The acid catalyst preferably used in the present invention is one that can remove a substituent bonded to a desired polymer chain, does not inhibit pore formation, and does not destroy the microphase separation structure. It can be used without any particular restrictions. As such an acid catalyst, an acid compound or a compound that generates an acid compound by photoirradiation or heating (a photoacid generator or a thermal acid generator) can be used.
As the acid compound, for example, a known compound such as p-toluenesulfonic acid can be used. As the compound that generates an acid compound, for example, a known compound can be used such as a sulfonium compound such as triphenylsulfonium triflate, an iodonium compound such as diphenyliodonium triflate, or a nitrobenzyl ester compound.
The acid catalyst is appropriately selected according to the object to be applied and the production process of the organic functional thin film applied thereto.
[0044]
The functional dye used in the organic functional thin film of the present invention is a compound that changes its optical constant in the heat mode (pyrolysis, etc.) by the laser irradiation energy, or the photon mode in the laser irradiation energy. There are compounds that change the optical constant.
Examples of the compound that changes its optical constant in the heat mode (thermal decomposition, etc.) depending on the laser irradiation energy include, for example, polymethine dyes, squarylium-based, pyrylium-based, porphyrin-based, porphyrazine-based, azo-based, azomethine-based dyes, etc. These metal complex compounds are mentioned.
Furthermore, as a compound that changes its optical constant in photon mode by laser irradiation energy, for example, fulgides, diarylethenes, azobenzenes, spiropyrans, stilbenes, dihydropyrenes, thioindigos, bipyridines, aziridines, Examples thereof include photochromic materials such as aromatic polycycles, allylidene anilines, and xanthenes.
[0045]
In the above compound, a photochromic material capable of rewriting recording is particularly preferable. Moreover, said compound may be used independently and may be used in combination of 2 or more types.
Further, in addition to the above compounds, for the purpose of improving properties, etc., together with stabilizers (eg transition metal complexes), ultraviolet absorbers, dispersants, flame retardants, lubricants, antistatic agents, surfactants, plasticizers, etc. It can also be used.
The dot diameter of the functional dye introduced into the pores of the organic functional thin film is 5 nm to 500 nm, preferably 10 nm to 200 nm.
[0046]
Next, the manufacturing method of the organic functional thin film of this invention is demonstrated.
The organic functional thin film in the present invention can be produced by the following production method. In addition, in order to promote microphase separation in each manufacturing method, you may add another polymer other than a block copolymer.
[0047]
The first method is to first prepare a solution containing a block copolymer in which polymer chains that are incompatible with each other are bonded, and then thin the film by a dip coating method, a spin coating method, etc. To form a microphase-separated structure (a step of forming an organic thin film having a microphase-separated structure), and then contact an acid with the organic thin film (a step of bringing an acid into contact with the organic thin film) and heat it. The detachable substituent bonded to the polymer chain is removed by an acid-catalyzed reaction (step of forming vacancies), and a functional dye is introduced into the nanometer-size vacancies formed by detachment of the substituent (to the vacancies) This is a production method for obtaining an organic functional thin film having an ordered structure of the present invention by incorporating a functional dye.
[0048]
The second method is to first prepare a solution containing a block copolymer in which polymer chains that are incompatible with each other are bonded, and then thin the film by a dip coating method, a spin coating method, etc. To form a microphase-separated structure (step of forming an organic thin film having a microphase-separated structure), and then contact the organic acid thin film with a photoacid generator (step of contacting the organic thin film with a photoacid generator) Further, after irradiation with light, heating is performed to remove a detachable substituent bonded to the polymer chain by an acid-catalyzed reaction (a step of forming a vacancy), and a nanometer-sized vacancy formed by the detachment of the substituent is obtained. It is a manufacturing method which obtains the organic functional thin film of the ordered structure of this invention by introduce | transducing a functional pigment | dye (process to make a void | hole contain a functional pigment | dye).
[0049]
The third method is to generate a photoacid that is compatible only with a block copolymer in which polymer chains that are incompatible with each other are bonded and a separated phase formed by the polymer chain having the detachable substituent. After preparing a solution containing an agent, the film is thinned by a dip coating method, a spin coating method, or the like, and a microphase separation structure is formed by solvent casting or temperature change (step of forming an organic thin film having a microphase separation structure) ) Next, after irradiating the organic thin film with light, the organic thin film is heated to remove the detachable substituent bonded to the polymer chain by an acid catalyzed reaction (step of forming vacancies). This is a production method for obtaining an organic functional thin film having an ordered structure of the present invention by introducing a functional dye into nanometer-sized pores (step of incorporating a functional dye into pores).
In addition, as a photo-acid generator, the above-mentioned well-known compounds can be used.
[0050]
The fourth method is to first prepare a solution containing a block copolymer in which polymer chains that are incompatible with each other are bonded, and then thin the film by a dip coating method, a spin coating method, etc. To form a microphase-separated structure (step of forming an organic thin film having a microphase-separated structure), and then contact the organic thin film with a thermal acid generator (step of contacting the organic thin film with a thermal acid generator) Further, when heated, the detachable substituent bonded to the polymer chain is removed by an acid-catalyzed reaction (step of forming a vacancy), and a functional dye is introduced into the nanometer-sized vacancy formed by the detachment of the substituent. This is a manufacturing method for obtaining an organic functional thin film having an ordered structure of the present invention by performing (a step of incorporating a functional dye into pores).
In addition, as a thermal acid generator, the above-mentioned known compounds can be used.
[0051]
As a method for introducing a functional dye into the pores of an organic thin film formed by any one of the four methods, for example, an organic thin film in which holes are formed and a functional dye solution (dissolving or dispersing the functional dye in a solvent) ) Can be introduced (embedded) into the pores of the organic thin film by a wet method performed by contact with the substrate by dipping or coating. The method of introducing the functional dye into the organic thin film is not limited to this, and a suitable method is appropriately selected according to the target application object, its material, form, manufacturing process, and the like. .
[0052]
Next, an optical recording medium in which the organic functional thin film is applied as a recording material (recording layer) will be described.
A conventional optical recording medium includes a recording layer composed of a continuous recording material (a layer in which the recording material exists). The recording layer is irradiated with a laser beam, and some change corresponding to the shape of the laser beam ( (Physical and chemical changes accompanying optical changes) are formed on the recording material and recorded. Therefore, since the size of the minimum recording pit depends on the laser beam diameter determined by the oscillation wavelength of the optical system and the NA of the lens, in the conventional recording / reproducing system, the increase in density is basically the laser oscillation wavelength or lens. Has been influenced by the practical technology of NA.
Also, because the beam shape is a Gaussian distribution and there is almost no material that changes with a clear threshold for heat or light as a recording material, the size and change of the outermost circumference of the pits formed The amount is not uniform, and there is always a variation factor in the quality of the reproduced signal, and there is a limit to obtaining high quality signal characteristics.
[0053]
The recording medium of the present invention is an optical recording medium having a new structure that overcomes the problems of the conventional recording medium. That is, in the optical recording medium to which the organic functional thin film of the present invention is applied, the nanometer-sized recording layer dots formed by the functional dye are highly ordered through the matrix in the continuous layer, and are discontinuously present. It is a structure to do. The size of the recording layer dots is 10 to 500 nm and is formed uniformly.
Therefore, by using such a nanometer-sized recording layer dot formed in advance, the minimum recording pit size is determined only by the recording layer dot to be formed without being determined by the laser oscillation wavelength or lens NA. Therefore, a recording medium having an arbitrary recording density can be designed. Furthermore, since the outermost peripheral edge of the recording pit is also determined by the structure of this organic functional thin film, high quality signal characteristics without pit variation can be obtained by recording the entire recording layer dot. Can be obtained.
[0054]
The configuration of the optical recording medium of the present invention and the necessary physical properties thereof will be described below.
<Recording medium configuration>
The optical recording medium of the present invention is provided with a recording layer comprising the organic functional thin film on a substrate, but as necessary, as a constituent layer, an undercoat layer, a metal reflective layer, a protective layer, a substrate surface hard coat layer, etc. The form of the constituent layer is selected according to the purpose and required characteristics. The optical recording medium of the present invention will be described with reference to the drawings.
The optical recording medium of the present invention has a configuration such as the example shown in the schematic cross-sectional views of FIGS. 2 (a) to 2 (d) and FIGS. 3 (a) to 3 (e). That is, in the case of FIGS. 2A to 2D, an example is shown in which a metal reflective layer is not provided on the substrate. 3A to 3E show examples in which a metal reflective layer is provided.
The structure of the optical recording medium of the present invention may be a write-once optical disk structure (a so-called air sandwich structure in which two recording layers are provided on a substrate) and a CD-R structure (recording on a substrate). Providing a layer, a reflective layer, and a protective layer), or a DVD structure in which a CD-R structure is bonded. The above configuration is an example for describing the embodiment, and other configurations may be used. Hereinafter, each constituent layer of the optical recording medium will be described.
[0055]
<substrate>
The substrate used in the optical recording medium of the present invention must be transparent to the laser used only when recording / reproduction is performed from the substrate side, and when recording / reproduction is performed from the recording layer side (opposite side of the substrate). The substrate need not be transparent.
As the substrate material, for example, plastic such as polyester, acrylic resin, polyamide, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, polyimide, glass, ceramic, or metal can be used. Note that a guide groove for tracking, a guide pit, and a preformat such as an address signal may be formed on the surface of the substrate.
[0056]
<Recording layer>
The recording layer is capable of causing some kind of change (change in optical characteristics or change in shape) by irradiation with laser light, recording information by the change, and optically reproducing the recording layer. The polymer chain that forms one separated phase of the microphase-separated structure is removable, with a microphase-separated structure formed by a block copolymer in which polymer chains that are incompatible with each other are bonded. And a functional dye is contained in the vacancies formed by the elimination of the substituent.
As for the optical characteristics of the functional dye, when reproducing using the change in absorption characteristics with respect to the recording / reproducing laser wavelength, it is preferable to control the wavelength so as to have the maximum absorption wavelength near the laser wavelength. When reproduction is performed using the refractive index change with respect to the reproduction laser wavelength, it is preferable to control the wavelength so that the maximum refractive index is in the vicinity of the laser wavelength.
[0057]
In addition, as a reproduction method, the method of reproducing the change by changing the fluorescence characteristics by laser irradiation can reproduce with high contrast even with a slight change. When the nanometer size is determined in advance, it is possible to record with significantly lower energy than in the conventional method.
In the case of the conventional method (method from the light source side), a clear pit shape could not be formed unless recording was performed with sufficient irradiation energy. For this reason, recording was not possible unless the reaction rate of the recording material by laser irradiation was high. On the other hand, the recording medium in which pits are formed in advance can be reproduced even with a small reaction rate, and is particularly effective in fluorescence reproduction.
[0058]
<Underlayer>
The undercoat layer consists of (1) improved adhesion, (2) a barrier such as water or gas, (3) improved storage stability of the recording layer, (4) improved reflectance, and (5) a substrate from a solvent. And (6) formation of guide grooves, guide pits, and preformats.
For the purpose of (1), polymer materials such as ionomer resins, polyamide resins, vinyl resins, natural resins, natural polymers, silicones, various rubber compounds such as liquid rubber, and silane coupling agents. Can be used.
For the purpose of (2) or (3), in addition to the above polymer materials, inorganic compounds such as SiO, MgF, SiO₂, TiO, ZnO, TiN, SiN, and the like, and metal or semimetal such as Zn, Cu, Ni, Cr, Ge, Se, Au, Ag, Al, etc. can be used.
For the purpose of (4), metals such as Al, Au, and Ag, and organic thin films having metallic luster such as methine dyes and xanthene dyes can be used.
For the purpose of (5) or (6), an ultraviolet curable resin, a thermosetting resin, a thermoplastic resin, or the like can be used.
The thickness of the undercoat layer is 0.01 to 30 μm, preferably 0.05 to 10 μm.
[0059]
<Metal reflective layer>
The metal reflective layer is used when necessary according to the required reflectance.
As the reflective layer, a metal or semimetal that is highly corrosive and is not easily corroded is used, and examples of such materials include Au, Ag, Cr, Ni, Al, Fe, and Sn. . Among these materials, Au, Ag, and Al are most preferable from the viewpoint of reflectance and productivity. These metals and metalloids may be used alone or as two kinds of alloys.
Examples of the method for forming the reflective layer include, but are not limited to, vapor deposition and sputtering. The thickness of the reflective layer is preferably from 50 to 5000 mm, more preferably from 100 to 3000 mm.
[0060]
<Protective layer, hard coat layer on substrate surface>
The protective layer and the hard coat layer on the substrate surface are (1) protecting the recording layer (reflection / absorption layer) from scratches, dust, dirt, etc. (2) improving the storage stability of the recording layer (reflection / absorption layer), (3 ) Used for the purpose of improving the reflectance. For these purposes, the materials shown in the undercoat layer can be used.
In addition, as inorganic materials, SiO, SiO₂Can also be used, such as polymethyl acrylate, polycarbonate, epoxy resin, polystyrene, polyester resin, vinyl resin, cellulose, aliphatic hydrocarbon resin, natural rubber, styrene butadiene resin, chloroprene rubber, wax, alkyd resin, Thermal softening and heat melting resins such as drying oil and rosin can also be used.
The most preferable example among the above materials is an ultraviolet curable resin excellent in productivity. The film thickness of the protective layer or the substrate surface hard coat layer is 0.01 to 30 μm, preferably 0.05 to 10 μm.
In the present invention, the undercoat layer, the protective layer, and the substrate surface hard coat layer have the same stabilizers, dispersants, flame retardants, lubricants, antistatic agents, surfactants, plasticizers, etc. as in the recording layer. Can be contained.
[0061]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the examples.
Examples 1-3: Examples relating to organic thin films
It consists of poly (p-tert-butoxycarbonyloxystyrene) (PBOCST) and polymethyl methacrylate (PMMA) having a number average molecular weight of about 50,000, and the volume fractions of PBOCST are 16 vol% (Example 1) and 33 vol%, respectively. (Example 2) A block copolymer of 52 vol% (Example 3) was synthesized by the living radical method.
The obtained block copolymer having the volume fraction of Example 1 to Example 3 was dissolved in cyclohexanone to form a cast film (organic thin film) on mica. Furthermore, this cast film was heat-treated at 140 ° C. for 8 hours, and the phase separation structure was examined by small-angle X-ray scattering (SAXS) measurement and transmission electron microscope (TEM) observation. As a result, it was confirmed that the phase separation structure in each example was a spherical structure (Example 1), a columnar structure (Example 2), and a lamella structure (Example 3) each of several tens of nm or less.
Next, the cast film of each example produced was immersed in a 1 wt% isopropyl alcohol solution of p-toluenesulfonic acid, and then heat-treated at 90 ° C. for 5 minutes. When the cast film was observed with an atomic force microscope (AFM), it was confirmed that pores were formed in the polymer chain portion which is the PBOCST structure portion of the block copolymer in any of the examples. (The portion where the pores are formed corresponds to the place where the substituent was eliminated and changed to poly-p-hydroxystyrene (PHS)).
Further, the cast film of each example in which pores were formed was designated as tris (p-dimethylaminophenyl) methylium SbF.₆Was immersed in a 0.5 wt% methanol / pyridine (: 20/1) solution. As a result of observing the surface layer of this cast film by TEM, it was confirmed that in all cases, the dye was segregated in the PHS portion, and an ordered structure containing the dye in the pores was formed.
[0062]
Example 4
A block copolymer composed of polystyrene (PST) having a number average molecular weight of about 70,000 and poly-tert-butyl methacrylate (PtBMA) and having a PtBMA volume fraction of 28 vol% was synthesized by the living radical method.
The obtained block copolymer and triphenylsulfonium triflate were dissolved in cyclohexanone so as to be 100: 3, and a cast film (organic thin film) was formed on mica.
The obtained cast film was heat-treated at 140 ° C. for 10 hours, and the phase separation structure was examined by SAXS measurement and TEM observation. As a result, it was confirmed that the phase separation structure was a columnar structure of several tens of nm or less.
Further, the cast film having the above phase separation structure was irradiated with light, then heated at 100 ° C. for 3 minutes and observed by AFM. As a result, the polymer chain portion, which is the PtBMA structure portion of the block copolymer, was emptied. It was confirmed that pores were formed (the portion where the pores were formed corresponds to the place where the substituent was eliminated and changed to polymethacrylic acid (PMAA)).
Furthermore, a 1 wt% aqueous solution of 3,3,3 ′, 3′-tetramethyl-1,1′-bis (3-sulfoethyl) -2,2′-indodicarbocyanine hydroxide triethylamine salt is added to the cast film in which pores are formed. Dropped and dried. As a result of observing the surface layer of this cast film with TEM, it was confirmed that the dye was segregated into a columnar structure (PMAA part) and an ordered structure containing the dye in the pores was formed. .
[0063]
Comparative Example 1
When p-toluenesulfonic acid was used instead of the acid catalyst triphenylsulfonium triflate used in Example 4, a columnar structure was confirmed, but no vacancies were confirmed.
[0064]
From the results of Examples 1 to 4 above, spherical, columnar, and lamellar phase separation structures were formed in the block copolymer, and ordered nanometer-sized vacancies based on elimination of substituents were formed in the separation phase. Thus, it has been possible to produce an organic functional thin film in which a functional dye is selectively contained in the formed pores. Useful and novel properties (optical properties, electronic properties, conductive properties, etc.) are manifested by the function of the functional dye and the highly ordered structure of the organic functional thin film.
In the case of Comparative Example 1 as described above, no vacancies were confirmed, but this was because the leaving group also came off together when heating to build a microphase separation structure, Therefore, it is considered that block copolymerization of PST and PMAA was performed from the beginning, resulting in a state in which voids could not be formed (a gap would not be formed) during later void formation.
[0065]
Example 5: Example relating to recording medium
The cyclohexanone solution of the block copolymer synthesized in Example 3 was spin-coated on a 1 mm thick, 5 cm square quartz substrate. However, the spin coating stopped rotating when the solvent spread evenly.
Next, the quartz substrate on which the block copolymer solution was spin-coated was dried and further subjected to heat treatment at 130 ° C. for 5 hours. After observing the phase separation structure of the organic thin film thus obtained with a TEM and confirming that it was a lamellar structure, a 1 wt% methanol solution of p-toluenesulfonic acid was dropped and heated at 100 ° C. for 3 minutes. . Further, it was immersed in a dye solution in the same manner as in Example 3, and the dye was introduced (embedded) into a lamellar structure composed of PHS to obtain a recording material.
A semiconductor laser beam having an oscillation wavelength of 635 nm and a beam diameter of 1 μm was applied to this recording medium at a distance of 1.5 cm in the horizontal direction.²I scanned it. The irradiated part and the unirradiated part were observed with a TEM and an optical microscope, the reflectance and transmittance were measured with a microspectroscopy, and the fluorescence was observed. The results are shown in Table 1 below.
[0066]
Comparative Example 2
A recording medium was prepared and recorded in the same manner as in Example 5 except that it was not immersed in the dye solution, and the irradiated part and the unirradiated part were observed with a TEM and an optical microscope, and the reflectance and transmittance by a microspectroscopy method. Measurement and fluorescence observation were performed. The results are shown in Table 1 below.
[0067]
[Table 1]

[0068]
Evaluation results
From the results of Examples and Comparative Examples, it was confirmed that the organic thin film of the recording material of Example 5 according to the present invention was recorded on the dye embedded in the PHS by laser light irradiation, and recording was possible. Became clear.
In this experiment, recording was performed using a light source with a large diameter (1 μm) compared to the diameter of the dye dots (several tens of nm), so a large number of nanometer-sized dye dots formed on the recording medium were recorded at a time. However, it was found that the dye dots can be individually recorded if recording is performed with a beam diameter comparable to that of the dye dots.
In addition, since the recording signal can be reproduced as a change in reflectance, in the method of reproducing using this phenomenon, the maximum absorption wavelength of the functional dye is controlled near the oscillation wavelength of the recording / reproducing laser, or the functional dye is used. It has been found that it is most preferable to control the maximum refractive index.
Further, it can be recognized that the recording signal can be reproduced as the presence or absence of fluorescence, and can be reproduced with a large S / N ratio compared to the above-described transmittance and reflectance. It was.
[0069]
【The invention's effect】
The present invention binds a detachable substituent to a polymer chain constituting one separated phase of a microphase separation structure formed using a block copolymer in which polymer chains that are incompatible with each other are bonded, By removing these substituents to form nanometer-sized ordered vacancies, and by introducing functional dyes into these vacancies, new optical properties, electronic properties, conductive properties, etc. It is possible to provide organic functional thin films that demonstrate their functions. The substituent is preferably a group capable of leaving by an acid catalyst.
In particular, by using an organic functional thin film having an ordered dot structure (dot array) composed of nanometer-sized functional dyes as a recording material (recording layer), the oscillation wavelength of the irradiated laser light or the lens It is possible to provide an optical recording medium capable of recording / reproducing at a recording density exceeding the diffraction limit of the laser pickup without depending on NA.
Further, the organic functional thin film forms at least a step of forming an organic thin film having a block copolymer microphase separation structure and a vacant hole by removing a detachable substituent bonded to the polymer chain by an acid catalytic reaction. It can be manufactured by a manufacturing process including a process and a process of incorporating a functional dye into the pores, thereby enabling to provide a composite organic functional thin film by controlling the structure.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a microphase separation structure ((a) spherical structure, (b) columnar structure, (c) lamellar structure) of one separated phase containing a functional dye in the organic functional thin film of the present invention. FIG.
FIG. 2 is a schematic cross-sectional view showing layer configuration examples (a) to (d) in the case where a metal reflective layer of an optical recording medium provided with the organic functional thin film of the present invention is provided in a recording layer.
FIG. 3 is a schematic cross-sectional view showing layer configuration examples (a) to (e) in the case where a metal reflective layer of an optical recording medium provided with the organic functional thin film of the present invention is provided in a recording layer.
[Explanation of symbols]
1 Substrate
2 Recording layer
3 Underlayer
4 Protective layer
5 Substrate surface hard coat layer
6 Metal reflective layer

Claims (15)

A polymer chain having a microphase separation structure formed by a block copolymer in which polymer chains that are incompatible with each other are bonded, and the polymer chain forming one separated phase of the microphase separation structure has a removable substituent And an organic functional thin film characterized in that a functional dye is contained in pores formed by elimination of the substituent. The microphase separation structure of the separation phase formed by the polymer chain having a detachable substituent is spherical, columnar, lamellar, co-continuous, or a structure similar to each of the shapes. 2. The organic functional thin film according to 1. 3. The organic functional thin film according to claim 1, wherein the boiling point of the substituent eliminated from the polymer chain is not more than the glass transition point (Tg) of the block copolymer. The organic functional thin film according to any one of claims 1 to 3, wherein the substituent leaving from the polymer chain is a group represented by the following structural formula (I) or structural formula (II).

It has a microphase-separated structure formed by a block copolymer in which polymer chains that are incompatible with each other are bonded, and the polymer chain forming one separated phase of the microphase-separated structure can be removed by an acid catalyst A method for producing an organic functional thin film having a substituent and containing a functional dye in pores formed by elimination of the substituent,
Preparing a solution containing the block copolymer, forming the thin film by coating the prepared solution to form an organic thin film having a microphase separation structure;
Contacting the organic thin film with an acid;
A step of forming a void by desorbing a substituent bonded to the polymer chain by an acid catalyst which is brought into contact with the organic thin film by heating;
Adding a functional dye to the pores;
The manufacturing method of the organic functional thin film characterized by including. It has a microphase-separated structure formed by a block copolymer in which polymer chains that are incompatible with each other are bonded, and the polymer chain forming one separated phase of the microphase-separated structure can be removed by an acid catalyst A method for producing an organic functional thin film having a substituent and containing a functional dye in pores formed by elimination of the substituent,
Preparing a solution containing the block copolymer, forming the thin film by coating the prepared solution to form an organic thin film having a microphase separation structure;
Contacting the organic acid thin film with a photoacid generator;
A step of detaching a substituent bonded to the polymer chain to form vacancies with an acid generated from a photoacid generator heated and brought into contact with the organic thin film after light irradiation; and
Adding a functional dye to the pores;
The manufacturing method of the organic functional thin film characterized by including. It has a microphase-separated structure formed by a block copolymer in which polymer chains that are incompatible with each other are bonded, and the polymer chain forming one separated phase of the microphase-separated structure can be removed by an acid catalyst A method for producing an organic functional thin film having a substituent and containing a functional dye in pores formed by elimination of the substituent,
A solution containing the block copolymer and a photoacid generator that is compatible only with the separated phase formed by the polymer chain having the detachable substituent is prepared, and the prepared solution is applied to the coated thin film. The organic thin film having a microphase-separated structure is formed, and the substituent bonded to the polymer chain is removed by the acid generated from the photoacid generator contained by heating the organic thin film after light irradiation. Forming a hole by separating, and
Adding a functional dye to the pores;
The manufacturing method of the organic functional thin film characterized by including. It has a microphase-separated structure formed by a block copolymer in which polymer chains that are incompatible with each other are bonded, and the polymer chain forming one separated phase of the microphase-separated structure can be removed by an acid catalyst A method for producing an organic functional thin film having a substituent and containing a functional dye in pores formed by elimination of the substituent,
Preparing a solution containing the block copolymer, forming the thin film by coating the prepared solution to form an organic thin film having a microphase separation structure;
Contacting the organic thin film with a thermal acid generator;
A step of releasing a substituent bonded to the polymer chain with an acid generated from a thermal acid generator that is brought into contact with heating of the organic thin film to form a void;
Adding a functional dye to the pores;
The manufacturing method of the organic functional thin film characterized by including. The method for producing an organic functional thin film according to claim 5, wherein the microphase separation structure is formed by solvent casting or temperature change. The method for producing an organic functional thin film according to any one of claims 5 to 9, wherein the step of incorporating a functional dye into the pores is performed by a wet method using a solvent. An optical recording medium provided with a recording layer comprising an organic functional thin film on a substrate,
The organic functional thin film has a microphase separation structure formed by a block copolymer in which polymer chains that are incompatible with each other are bonded, and the polymer chain forming one separated phase of the microphase separation structure is removed. An optical recording medium having a separable substituent, wherein a functional dye is contained in pores formed by elimination of the substituent. It has a micro phase separation structure formed by a block copolymer in which polymer chains that are incompatible with each other are bonded to each other on the substrate, and the polymer chain forming one separated phase of the micro phase separation structure can be detached. A recording layer made of an organic functional thin film containing a functional dye is provided in holes formed by elimination of the substituent, and the optical characteristics of the functional dye are irradiated by laser irradiation. An optical recording medium which is recorded and reproduced while being changed. 13. The optical recording medium according to claim 12, wherein the functional dye is a dye whose wavelength is controlled to have a maximum absorption wavelength in the vicinity of the wavelength of the recording / reproducing laser. 13. The optical recording medium according to claim 12, wherein the functional dye is a dye whose wavelength is controlled so as to have a maximum refractive index in the vicinity of the wavelength of the recording / reproducing laser. The optical recording medium according to claim 12, wherein the functional dye is a photochromic dye.

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