JP2004030885A

JP2004030885A - Manufacturing method and manufacturing apparatus for multi-layered optical information recording medium

Info

Publication number: JP2004030885A
Application number: JP2003130363A
Authority: JP
Inventors: Kazuhide Hayashi; 林　　一英; Kazuya Hisada; 久田　和也; Kazuhiro Tomaru; 東丸　一弘; Eiji Ono; 大野　鋭二
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2002-05-10
Filing date: 2003-05-08
Publication date: 2004-01-29
Anticipated expiration: 2023-05-08
Also published as: JP4112423B2

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that unevenness is caused in the thickness of a separation layer in the case of transferring signal pits by a stamper to the surface of a substrate together with the separation layer between the substrate and the stamper by using the stamper on the thick substrate, on the surface of which the signal pits are formed and on which a rewritable recording multi-layered film is formed. <P>SOLUTION: A thickness distribution thicker in the inner circumferential part and gradually getting thinner toward the outer circumferential part in the radial direction is provided to a transfer layer 103 on the surface of the stamper 100, an adhesive layer 107 is formed between the surface of the signal substrate 105 on which the signal recording film 106 exists and the stamper 100 with the transfer layer 103 formed thereon, and the adhesive layer 107 has a thickness distribution thinner in its inner circumferential part and gradually getting thicker toward its outer circumferential part. Since the thickness distribution in the radial direction is opposite between the transfer layer 103 and the adhesive layer 107 to each other, the thickness distribution of the separation layer 110 having the two layers is made uniform. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、複数の信号記録層の間に分離層を有する片面より記録及び再生を行う、多層光情報記録媒体の製造方法および製造装置に関するものである。
【０００２】
【従来の技術】
高密度光情報記録媒体として、片面２層再生のＤＶＤのような厚み方向に信号記録面を複数層有する、多層光情報記録媒体が提案されている。たとえば、片面２層再生のＤＶＤは２枚の基板のうち１枚の情報記録面に金、シリコン等の透光性の反射層を、もう一枚の情報記録面に従来のアルミニウム等からなる反射層を、それぞれ成膜し、これらの情報記録面が内側になるように貼り合せた構造となっている。
【０００３】
さらに、１層あたりの面記録密度を向上するために、青紫色レーザ光源（波長４００ｎｍ前後）と高ＮＡのレンズを用い、厚さが０．１ｍｍといった薄型の記録再生側透明カバー層を持つ高密度光情報記録媒体が提案されている。この高密度光情報記録媒体は、厚い信号基板の表面に信号の案内溝あるいはピットを形成して、その上に書き換え可能な記録多層膜を成膜、さらにその上に透明カバー層が形成された構造になっている。この薄型透明カバー層タイプの高密度光情報記録媒体でも２つの信号記録面を有するものが考えられる。その作製方法の一つの例としては以下の方法が挙げられる。
【０００４】
（１）表面に信号の案内溝あるいはピットが形成され、書き換え可能な記録多層膜が成膜された厚い基板の上に、さらに紫外線硬化樹脂を用いて分離層を形成するとともに、その分離層の表面に２層目の信号の案内溝あるいはピットを形成する。
【０００５】
（２）２層目の信号の案内溝あるいはピットの上に書き換え可能な透光性の記録多層膜を成膜する。
【０００６】
（３）厚さが０．１ｍｍといった薄型の記録再生側透明カバー層を形成する。
【０００７】
具体的な作製方法として（例えば、特許文献１参照。）、上記（１）の工程のためにプラスチック製のスタンパ２１００を用いて、そのスタンパ２１００上の信号案内溝あるいはピットを覆って第１の紫外線硬化樹脂を塗布し硬化する。その後、異なる性質を有する第２の紫外線硬化樹脂を接着層として用いて、１層目の信号記録層２１０６が成膜された基板と硬化された第１の紫外線硬化樹脂とを貼り合わせ、第２の紫外線硬化樹脂の硬化後スタンパ２１００を剥離している。このようにして第１の紫外線硬化樹脂と第２の紫外線硬化樹脂から分離層２１１０が形成される。このような方法を用いれば、剛性のある厚い信号基板２１０５をベースとして、その上に分離層２１１０を介して、もう一層の信号記録層２１０６、さらには複数の信号記録層２１０６を積み上げて多層光情報記録媒体を作製することができる。
【０００８】
【特許文献１】
特開２００２−２６０３０７号公報
【０００９】
【発明が解決しようとする課題】
しかしながら、多層光情報記録媒体の信号記録層２１０６の間に存在する分離層２１１０の厚みは均一である必要がある。分離層２１１０の厚みが均一であれば、分離層２１１０の前後にある一方の信号記録層２１０６では記録あるいは再生の際に受ける他方の信号記録層２１０６からの反射光の影響が一定になる。他方の信号記録層２１０６からの反射光が変動すると、再生信号の外乱成分となり、Ｓ／Ｎが悪化する。逆に、分離層２１１０の厚みが均一であれば、他方の信号記録層２１０６からの外乱が一定であるため、記録あるいは再生が安定になり、再生信号の品質は向上する。
【００１０】
図１２は、従来の多層光情報記録媒体を製造する際の、信号基板２１０５またはスタンパ２１００への紫外線硬化樹脂の滴下量の時間変化と、紫外線硬化樹脂が滴下された状態の信号基板２１０５またはスタンパ２１００の回転数を示す図である。図１２に示すように、従来の製造方法では、信号基板２１０５またはスタンパ２１００の中心部付近に紫外線硬化樹脂を滴下させ、滴下が終了した後、信号基板２１０５またはスタンパ２１００を回転させることにより、その遠心力によって紫外線硬化樹脂が信号基板２１０５またはスタンパ２１００の中心部付近から外側に向かって引きのばされていた。
【００１１】
上記のような製造方法では、スタンパ２１００または信号基板２１０５が回転するときの遠心力により、紫外線硬化樹脂は、スタンパ２１００または信号基板２１０５の中心側よりも外側の方においてその厚みが厚くなる。従って、図１３に示すように、異なる性質の紫外線硬化樹脂を合わせて形成された分離層２１１０も中心側から外側に向かってその厚みが厚くなる傾向となり、上記のように、従来の製造方法による多層光情報記録媒体のＳ／Ｎ比は満足できるものではなかった。
【００１２】
本発明は、上記従来の製造方法の課題に鑑み、分離層を挟む信号記録層への記録及び信号記録層からの再生を安定に行うことができ、良質な信号を得ることができる多層光情報記録媒体を製造する方法及び装置を提供することを目的とする。
【００１３】
【課題を解決するための手段】
上記課題を解決するための第１の本発明は、複数の信号記録層の間に分離層を有する片面より記録及び再生を行う、多層光情報記録媒体の製造方法であって、
（ａ）スタンパの上の、案内溝とピットの少なくとも一つを有する信号記録領域がある面に隣接して第ｎ＋１層を形成する工程と、
（ｂ）前記信号記録層を有する信号基板に隣接して第ｎ層を形成する工程と、を含み、
前記分離層は、前記第ｎ＋１層および前記第ｎ層を合わせることにより得られ、
前記第ｎ＋１層および前記第ｎ層のうち、少なくとも一方の層の半径方向の厚み分布を他方の層の半径方向の厚み分布に基づいて形成または制御する、多層光情報記録媒体の製造方法である。
【００１４】
前記第ｎ＋１層は所定の厚み分布を有して形成され、前記第ｎ層は所定の厚み分布を有して形成され、
前記少なくも一方の層の半径方向の厚み分布を他方の層の半径方向の厚み分布を考慮して制御する、第１の本発明の多層光情報記録媒体の製造方法である。
【００１５】
第２の本発明は、前記第ｎ＋１層および前記第ｎ層を所定の厚み分布を有して形成し、
前記少なくも一方の層の半径方向の厚み分布を他方の層の半径方向の厚み分布を考慮して制御する、第１の本発明の多層光情報記録媒体の製造方法である。
【００１６】
上記第１または第２の本発明の多層光情報記録媒体の製造方法によれば、第ｎ＋１層と第ｎ層とのいずれか一方の半径方向の厚み分布が他方を考慮しながら制御されるため、両方を有する分離層の厚み分布も制御でき、均一にすることができる。その結果、分離層を挟む信号記録層の記録及び再生を安定に行うことができ、かつ良質な信号を得ることができる。
【００１７】
第３の本発明は、前記分離層の半径方向の厚み分布が実質上均一である、第１または第２の本発明の多層光情報記録媒体の製造方法である。
【００１８】
上記第３の本発明の多層光情報記録媒体の製造方法によれば、第ｎ＋１層と第ｎ層とが両方半径方向の厚み分布が制御されるため、両方を有する分離層の厚み分布も制御でき、均一にすることができる。その結果、分離層を挟む信号記録層の記録及び再生を安定に行うことができ、かつ良質な信号を得ることができる。
【００１９】
第４の本発明は、前記スタンパを前記第ｎ＋１層から剥離する工程をさらに含む、第１の本発明の多層光情報記録媒体の製造方法である。
【００２０】
第５の本発明は、前記第ｎ＋１層の半径方向の厚み分布が、前記スタンパの内周部より外周部の方が薄く、前記第ｎ層の半径方向の厚み分布が、前記信号基板の内周部より外周部の方が厚い、第１の本発明の多層光情報記録媒体の製造方法である。上記製造方法によれば、第ｎ＋１層と第ｎ層を有する分離層を均一にすることができる。
【００２１】
第６の本発明は、前記第ｎ＋１層が放射線硬化材料であって、前記（ａ）の工程が、前記スタンパの内周部または前記信号基板の前記第ｎ層の内周部に前記放射線硬化材料を滴下する工程と、前記放射線硬化材料が滴下された前記スタンパまたは前記信号基板を回転する工程と、を含む、第５の本発明の多層光情報記録媒体の製造方法である。
【００２２】
第７の本発明は、前記放射線硬化材料が滴下された前記スタンパまたは前記信号基板を回転する工程の後に、
前記スタンパと前記信号基板とを前記第ｎ＋１層を内側にして重ね合わせる工程を行い、
その後、放射線を照射することにより前記放射線硬化材料を照射する工程を行う、第６の本発明の多層光情報記録媒体の製造方法である。
【００２３】
第８の本発明は、前記（ａ）の工程が、前記スタンパの内周部または前記第ｎ層の内周部に前記放射線硬化材料を滴下する工程と、前記放射線硬化材料が滴下された前記スタンパまたは前記信号基板を回転する工程とを含む、第６の本発明の多層光情報記録媒体の製造方法である。上記製造方法によれば、容易に第ｎ＋１層を形成することができる。
【００２４】
第９の本発明は、前記スタンパの内周部または前記信号基板の第ｎ層の内周部に前記放射線硬化材料を滴下する工程と前記放射線硬化材料が滴下された前記スタンパまたは前記信号基板を回転する工程との一部が同時になされる、第６〜８のいずれかの本発明の多層光情報記録媒体の製造方法である。上記製造方法によれば、容易に第ｎ＋１層の半径方向の厚み分布を制御することができる。
【００２５】
第１０の本発明は、前記スタンパの内周部または前記信号基板の第ｎ層の内周部に前記放射線硬化材料を滴下しながら、前記スタンパまたは前記信号基板を回転する、第６〜８の本発明のいずれかの多層光情報記録媒体の製造方法である。
【００２６】
第１１の本発明は、前記スタンパの内周部または前記信号基板の第ｎ層の内周部に前記放射線硬化材料を滴下する前に、前記スタンパまたは前記信号基板の第ｎ層の略中心に中心穴がある場合には前記中心穴に蓋をした上で、前記蓋の上から前記放射線硬化材料を滴下する、第６〜８の本発明のいずれかの多層光情報記録媒体の製造方法である。上記製造方法によれば、容易に第ｎ＋１層の半径方向の厚み分布を制御することができる。
【００２７】
第１２の本発明は、前記第ｎ＋１層の半径方向の厚み分布が、前記スタンパの内周部より外周部の方が厚く、前記第ｎ層の半径方向の厚み分布が、前記信号基板の内周部より外周部の方が薄い、第１の本発明の多層光情報記録媒体の製造方法である。上記構成によれば、第ｎ＋１層と第ｎ層を有する分離層を均一にすることができる。
【００２８】
第１３の本発明は、前記第ｎ層が放射線硬化材料であって、前記（ｂ）の工程が、前記スタンパの前記第ｎ＋１層の内周部あるいは前記信号基板の内周部に前記放射線硬化材料を滴下する工程と、前記放射線硬化材料が滴下された前記スタンパあるいは前記信号基板を回転する工程と、回転後に前記スタンパと前記信号基板の前記放射線硬化材料が塗布された面が内側となるように重ね合わせる工程と、放射線を照射することにより前記放射線硬化材料を硬化する工程とを含む、第１２の本発明の多層光情報記録媒体の製造方法である。上記製造方法によれば、容易に第ｎ＋１層の形成されたスタンパと信号基板を接着することができる。
【００２９】
第１４の本発明は、前記スタンパの内周部あるいは前記信号基板の内周部に前記放射線硬化材料を滴下する工程と、前記放射線硬化材料が滴下された前記スタンパあるいは前記信号基板を回転する工程との一部が同時になされる第１３の本発明の多層光情報記録媒体の製造方法である。上記製造方法によれば、容易に第ｎ層の半径方向の厚み分布を制御することができる。
【００３０】
第１５の本発明は、前記スタンパの内周部あるいは前記信号基板の内周部に前記放射線硬化材料を滴下しながら、回転する第１４の本発明の多層光情報記録媒体の製造方法である。
【００３１】
第１６の本発明は、前記放射線硬化材料を滴下する前に、前記スタンパあるいは前記信号基板の略中心に中心穴がある場合には前記中心穴に蓋をした上で、前記蓋の上から前記放射線硬化材料を滴下する第１３〜１５の本発明のいずれかの多層光情報記録媒体の製造方法である。上記製造方法によれば、容易に第ｎ層の半径方向の厚み分布を制御することができる。
【００３２】
第１７の本発明は、前記スタンパあるいは前記信号基板の前記放射線硬化材料が塗布された面が内側となるように重ね合わせる工程が減圧環境下で行われる第７または１３の本発明の多層光情報記録媒体の製造方法である。上記製造方法によれば、分離層内への気泡の混入を防ぐことができる。
【００３３】
第１８の本発明は、前記第ｎ＋１層が放射線硬化性を有する感圧性接着剤を含む第５または第１２の本発明の多層光情報記録媒体の製造方法である。上記製造方法によれば、感圧性接着剤は粘度が高いため厚み分布の制御が容易で、またスタンパからの信号の転写も確実にすることができる。
【００３４】
第１９の本発明は、前記第ｎ層が感圧性接着剤を含む第５または第１２の本発明の多層光情報記録媒体の製造方法である。上記製造方法によれば、感圧性接着剤は粘度が高いため第ｎ層の厚み分布の制御が容易である。
【００３５】
第２０の本発明は、前記第ｎ層が放射線硬化材料であって、前記（ｂ）の工程が、前記第ｎ層を形成するための接着用放射線硬化材料を、前記スタンパの前記第ｎ＋１層の上と前記信号基板の少なくとも一方に滴下する工程と、前記スタンパと前記信号基板を前記第ｎ＋１層が内側になるように重ね合わせ、前記スタンパと前記信号基板を回転させて前記接着用放射線硬化材料を延伸する工程、放射線を照射することにより前記放射線硬化材料を硬化する工程とを含む第５の本発明の多層光情報記録媒体の製造方法である。上記製造方法によれば、減圧しなくとも第ｎ層内の気泡は延伸により飛ばされるため、気泡の混入を防ぐことができる。
【００３６】
第２１の本発明は、前記第ｎ＋１層が放射線硬化材料であって、前記（ａ）の工程が、前記第ｎ＋１層を形成するための転写用放射線硬化材料を、前記スタンパと前記信号基板上前記第ｎ層の上の少なくとも一方に滴下する工程と、前記スタンパと前記信号基板を前記第ｎ層が内側になるように重ね合わせ、前記スタンパと前記信号基板を回転させて前記転写用放射線硬化材料を延伸する工程、放射線を照射することにより前記放射線硬化材料を硬化する工程とを含む第１２の本発明の多層光情報記録媒体の製造方法である。
【００３７】
第２２の本発明は、複数の信号記録層の間に分離層を有する片面より記録及び再生を行う、多層光情報記録媒体の製造装置であって、
前記信号記録層の上に前記分離層を形成する際に、スタンパの上の、案内溝とピットの少なくとも一つを有する信号記録領域がある面に、前記スタンパの半径方向に対して厚み分布を制御して第ｎ＋１層を形成する第ｎ＋１層形成手段と、
前記スタンパ上の前記第ｎ＋１層と、前記信号記録層を有する信号基板との間に、半径方向の厚み分布を制御された第ｎ層を形成して、前記スタンパ上の前記第ｎ＋１層と前記信号基板とを接着する接着手段と、
前記スタンパを前記第ｎ＋１層から剥離し、表面に前記スタンパ上の信号が転写された前記第ｎ＋１層と前記第ｎ層とを有する前記分離層を得る剥離手段とを備えた、多層光情報記録媒体の製造装置である。
【００３８】
上記本発明の多層光情報記録媒体の製造装置によれば、第ｎ＋１層と第ｎ層とが両方半径方向の厚み分布が制御されるため、両方を有する分離層の厚み分布も制御でき、均一にすることができ、歩留まり向上による量産性の向上が期待できる。また、分離層を挟む信号記録層の記録及び再生を安定に行うことができ、かつ良質な信号を得ることができる。
【００３９】
第２３の本発明は、前記第ｎ＋１層が放射線硬化材料であるとき、前記第ｎ＋１層形成手段が、
前記スタンパの内周部に前記放射線硬化材料を滴下する滴下手段と、前記放射線硬化材料が滴下された前記スタンパを回転する回転手段と、放射線を照射することにより前記放射線硬化材料を硬化する硬化手段とを有する第２２の本発明の多層光情報記録媒体の製造装置である。上記構成によれば、容易に第ｎ＋１層を形成することができる。
【００４０】
第２４の本発明は、前記スタンパの内周部に前記放射線硬化材料を滴下しながら、前記スタンパを回転する第２３の本発明の多層光情報記録媒体の製造装置である。
【００４１】
第２５の本発明は、前記スタンパの内周部に前記放射線硬化材料を滴下する前に、前記スタンパの略中心に中心穴がある場合には前記中心穴に蓋をした上で、前記蓋の上から前記放射線硬化材料を滴下する第２３または２４の本発明の多層光情報記録媒体の製造装置である。上記構成によれば、容易に第ｎ＋１層の半径方向の厚み分布を制御することができる。
【００４２】
第２６の本発明は、前記第ｎ層が放射線硬化材料であるとき、前記接着手段が、
前記スタンパの前記第ｎ＋１層の内周部あるいは前記信号基板の内周部に前記放射線硬化材料を滴下する滴下手段と、前記放射線硬化材料が滴下された前記スタンパあるいは前記信号基板を回転する回転手段と、回転後に前記スタンパと前記信号基板の前記放射線硬化材料が塗布された面が内側となるように重ね合わせる重ね合わせ手段と、放射線を照射することにより前記放射線硬化材料を硬化する硬化手段とを有する第２２の本発明の多層光情報記録媒体の製造装置である。上記構成によれば、容易に第ｎ＋１層の形成されたスタンパと信号基板を接着することができる。
【００４３】
第２７の本発明は、前記スタンパの内周部あるいは前記信号基板の内周部に前記放射線硬化材料を滴下しながら回転する、第２６の本発明の多層光情報記録媒体の製造装置である。
【００４４】
第２８の本発明は、前記放射線硬化材料を滴下する前に、前記スタンパあるいは前記信号基板の略中心に中心穴がある場合には前記中心穴に蓋をした上で、前記蓋の上から前記放射線硬化材料を滴下する第２６または第２７の本発明の多層光情報記録媒体の製造装置である。上記構成によれば、容易に第ｎ層の半径方向の厚み分布を制御することができる。
【００４５】
第２９の本発明は、前記重ね合わせ手段が減圧手段を併せ持ち、前記減圧手段により周囲を減圧環境にした上で前記スタンパと前記信号基板を重ね合わせる第２６の本発明の多層光情報記録媒体の製造装置である。上記構成によれば、分離層内への気泡の混入を防ぐことができ、歩留まりの向上が期待できる。
【００４６】
第３０の本発明は、前記第ｎ層が放射線硬化材料であるとき、前記接着手段が、
前記第ｎ層を形成するための接着用放射線硬化材料を、前記スタンパの前記第ｎ＋１層の上と前記信号基板の少なくとも一方に滴下する滴下手段と、前記スタンパと前記信号基板を前記第ｎ＋１層が内側になるように重ね合わせ、前記スタンパと前記信号基板を回転させて前記接着用放射線硬化材料を延伸する延伸手段と、放射線を照射することにより前記放射線硬化材料を硬化する硬化手段とを有する第２２の本発明の多層光情報記録媒体の製造装置である。上記構成によれば、減圧しなくとも第ｎ層内の気泡は延伸により飛ばされるため、気泡の混入を防ぐことができ、歩留まりの向上が期待できる。
【００４７】
第３１の本発明は、信号情報を有することができる基板層と、
前記基板層の上部に形成された第ｎ層と、
前記第ｎ層の上部に形成された第ｎ＋１層と、
前記第ｎ＋１層の上部に形成された保護層と、を備え、前記第ｎ層および第ｎ＋１層を合わせた厚みが均一である多層光情報記録媒体である。
【００４８】
第３２の本発明は、前記第ｎ＋１層の半径方向の厚みと前記第ｎ層の半径方向の厚みが互いに相反する、第３１の本発明の多層光情報記録媒体である。
【００４９】
【発明の実施の形態】
以下、本発明の実施の形態について、図面を用いて詳細に説明する。
【００５０】
（実施の形態１）
本実施の形態について図１を用いて説明する。ここでは、本発明の第ｎ＋１層の一例である転写層の半径方向の厚み分布がスタンパ（モールド）の内周部で厚く外周になるにつれて徐々に薄くなる傾向であり、また、本発明の第ｎ層の一例である接着層の半径方向の厚み分布が、信号基板の内周部で薄く外周になるにつれて徐々に厚くなる傾向である場合の例について示す。
【００５１】
図１に本発明の概念図を示す。まず、図１（ａ）に示すように、円形をなすスタンパ１００表面の凹凸部１０２の上に転写層１０３を形成する。信号記録領域に形成された凹凸部１０２は案内溝とピットの少なくとも一つを有する。例えば、アドレス情報を示すウォブルを有するトラックピッチ０．３２ミクロン、深さ２０ｎｍの溝が挙げられる。また、スタンパ１００の中心には中心穴１０１があってもよい。転写層１０３は、スタンパ１００の半径方向に対して内周部では厚く、外周部にかけて徐々に薄くなる厚み分布を有するように形成される。
【００５２】
次に、図１（ｂ）に示すように、信号基板１０５の表面には、本発明の信号記録層の一例である信号記録膜１０６が設けられている。信号基板１０５の信号記録膜１０６のある面と、転写層１０３が形成されたスタンパ１００の間に、接着層１０７を形成して、スタンパ１００と信号基板１０５を接着する。信号基板１０５には中心穴１０８があってもよい。ここで、接着層１０７は、半径方向に対して内周部では薄く、外周部にかけて徐々に厚くなる厚み分布を有するように形成される。転写層１０３と接着層１０７の半径方向の厚み分布が互いに逆であるため、その２つからなる分離層１１０の厚み分布は均一となる。最後に図１（ｃ）のように、スタンパ１００を転写層１０３との界面より剥離する。転写層１０３の表面にはスタンパ１００から転写された凹凸部１０９が形成される。転写層１０３はスタンパ１００上の凹凸部１０２を転写するための層であるが、転写層１０３とスタンパ１００の界面での剥離が容易となるように各々の材料を適宜選ぶ必要がある。
【００５３】
以上のようにして、半径方向に厚みが均一な分離層１１０を得る。分離層１１０の転写された凹凸部１０９には、信号記録膜３００１が形成されたのち、さらに分離層あるいは保護層３０００が形成される。以上が本発明の概略である。なお、信号基板１０５は信号記録膜１０６の下に他の信号記録層を有していてもよい（図示せず）。すなわち、信号記録膜１０６が分離層上に形成されていてもよいということである。
【００５４】
以下、図１（ａ）〜（ｃ）の各工程について詳細に説明する。
【００５５】
まず、転写層の形成工程について一例を用いて説明する。転写層の材料として本発明の放射線硬化材料の一例としての紫外線硬化樹脂を用いて、スピンコートにより転写層を形成する場合を図２と図３に示す。図２（ａ）に示すような中心穴１０１を有するスタンパ１００を準備する。中心穴１０１の直径は１５ｍｍ、スタンパ１００の外径は直径１２０ｍｍである。ここでは転写層の材料として紫外線硬化樹脂を用いるので、スタンパの材質は例えば、アクリル樹脂、オレフィン樹脂、ポリカーボネート、ノルボルネン系樹脂等の紫外線に対してある程度透明なプラスチックが好ましい。
【００５６】
次に、図２（ｂ）のように、スタンパ１００を回転テーブル２０１の上におく。回転テーブル２０１はスタンパ１００を真空吸引等の方法で固定する。そして、中心穴１０１は蓋２０２でカバーする。蓋２０２の外形は直径１５ｍｍ〜４２ｍｍの範囲のものでよいが、ここでは直径２２ｍｍのものである。蓋２０２の上にノズル２０５を配置して、転写層の材料である紫外線硬化樹脂２００を滴下しはじめる。滴下前に、回転テーブル２０１は回転していてもよい。紫外線硬化樹脂２００は粘度１５０ｍＰａ・ｓである。紫外線硬化樹脂２００としては、図１（ｃ）で示すように、スタンパ１００との界面で剥離しやすくなる材料を選ぶ必要がある。例えば、紫外線照射によりラジカル重合を起こすアクリル系材料等が挙げられる。樹脂の滴下時間は９ｓｅｃである。滴下とほぼ同時に、図２（ｃ）に示すように回転テーブル２０１を回転する。初期の６ｓｅｃは低速で、その後の回転数は２０００ｒｐｍであり、２０００ｒｐｍにおける回転時間は１０ｓｅｃである。したがって、滴下終了後７ｓｅｃ回転をつづける。回転後、回転テーブル２０１は停止する。
【００５７】
図３に停止した後の工程を示す。図３（ａ）は停止した直後の様子を示している。スタンパ内周部で厚く、外周部にかけて徐々に薄くなる傾向になっている。図３（ｂ）は半径方向に対する転写層の厚みを示すものである。半径２０ｍｍ付近では１５ミクロンくらいであり厚いが、中心から半径方向に離れるにつれ薄くなり、中心から半径方向に５８ｍｍの点で約１３ミクロンになる。このような厚み分布は、紫外線硬化樹脂の滴下時間と滴下時の回転テーブルの回転数、滴下停止後の回転時間により制御することができる。回転数と回転時間が大きくなると、半径方向の厚み分布の変化は小さくなり全体的に均一になる。
【００５８】
最後に図３（ｃ）に示すように、蓋２０２をスタンパ１００上より除去した上で紫外線ランプ２１０により紫外線硬化樹脂２００を硬化させ、転写層１０３を得る。硬化前に蓋２０２を除去する目的は、硬化後に紫外線硬化樹脂２００が固体化して、蓋２０２を除去しづらくなることを防ぐためである。蓋２０２の除去はロボットアームで掴んでもよいし、蓋の一部を磁性体で構成して磁石を用いて持ち上げても良い。図３（ｃ）では回転テーブル２０１上で硬化を行っているが、スタンパ１００を紫外線ランプが設置された異なるテーブルに移動させて硬化を行ってもよい。紫外線ランプ２１０としてはメタルハライドランプ、水銀ランプ、キセノンランプ等を用いることができる。
【００５９】
次に、接着層を形成する工程について一例を用いて説明する。ここでは、接着層として紫外線硬化樹脂を用いる場合を説明する。紫外線硬化樹脂としては、信号基板の材料や信号記録層の材料、また転写層１０３との接着力の強い材料を選択する必要がある。たとえば、アクリル系材料が挙げられる。図４にスピンにより接着層を延伸する場合を示す。図４（ａ）に示すように、まず信号記録膜１０６が形成された信号基板１０５を回転テーブル４０１上に配置して固定する。信号基板１０５の外径は直径１２０ｍｍ、中心穴１０８は直径１５ｍｍであり、材質はポリカーボネートやアクリル、またオレフィン等のプラスチックが用いられる。信号記録膜１０６は例えば、ＧｅＳｂＴｅやＡｇＩｎＳｂＴｅ等の相変化膜、磁性体膜、色素膜といった記録膜とそれらを挟むＺｎＳ等の誘電体膜、金属反射膜等であってもよい。一般にスパッタリングや蒸着によって成膜される。
【００６０】
回転テーブル４０１への固定は、信号基板１０５との接触面を真空吸引で行われる。回転テーブル４０１には中心穴１０８に嵌合するセンターピン４０２があり、信号基板１０５の中心出しが行われる。回転テーブル４０１を回転させて、信号基板１０５上の半径２０〜３０ｍｍの位置に配置されたノズル４００より紫外線硬化樹脂４０３を滴下する。ここでは紫外線硬化樹脂４０３として、粘度４５０ｍＰａ・ｓのアクリル樹脂を用いる。信号基板１０５が回転されるため、紫外線硬化樹脂４０３はリング状になる。
【００６１】
次に図２と図３に示した工程から得られるスタンパ１００を信号基板１０５の上に重ね合わせる。図４（ｂ）のように、信号基板１０５上にはリング状の紫外線硬化樹脂４０４が形成されており、その上方より転写層１０３がリング状の紫外線硬化樹脂４０４に接するようにスタンパ１００を重ね合わせす。スタンパ１００の中心穴１０１は直径１５ｍｍであるためセンターピン４０２と嵌合し、信号基板１０５とスタンパ１００の中心が互いに合う。重ね合わせは、転写層１０３とリング状の紫外線硬化樹脂４０４が接する際に混入する恐れのある気泡を防ぐため、減圧環境下で行ってもよい。
【００６２】
次に、図４（ｃ）に示すように回転テーブル４０１を高速回転し、紫外線硬化樹脂を全面に延伸する。ここでは、５０００ｒｐｍの高速で３０ｓｅｃ回転する。これにより、延伸された接着層４０５が転写層１０３と信号基板１０５の間に形成される。この後の剥離工程で剥離を安定に行うために、図４（ｃ）のように延伸された接着層４０５がスタンパ１００と直接接しないようにする必要がある。延伸の後、図３（ｃ）と同様、紫外線ランプによりスタンパ１００側より延伸された接着層４０５を硬化する。スタンパ１００が透明であるため、硬化が可能となる。
【００６３】
得られた接着層の厚み分布と、転写層と接着層からなる分離層の厚み分布を図５に示す。図５（ａ）のように接着層の厚み分布は高速回転による遠心力で、内周部で１０ミクロン、外周にかけて徐々に厚くなり外周端で１２．５ミクロンになっている。また、転写層と接着層からなる分離層の厚み分布は図５（ｂ）であり、図３（ｂ）と図５（ａ）が足されたものとなり、内周から外周まで２４．５±０．５ミクロンの範囲にあり、非常に均一になる。
【００６４】
最後に図６にスタンパの剥離工程について示す。ここでは、くさびと圧縮空気を用いた剥離方法を示す。図６（ａ）に示すように、接着工程で得られたスタンパ１００と信号基板１０５が接着された剥離前中間物６２０を固定台６００の上に固定する。固定法は真空吸引が好ましい。固定台６００にはセンターポスト６０１があり、その一部に吹き出し口６０２が設けられている。
【００６５】
次に、図６（ｂ）に示すように、センターポスト６０１よりくさび６１０を出し、スタンパ１００と転写層１０３の界面に挿入する。このとき、転写層１０３がくさび６１０により多少削ずれてもかまわない。くさび６１０が挿入されたのち、吹き出し口６０２より圧縮空気６１５が吹き出される。圧縮空気６１５はくさび６１０が挿入されたスタンパ１００と転写層１０３の界面に入り込み、スタンパ１００を剥がし始める。しばらく待つと図６（ｃ）のようにスタンパ１００は転写層１０３の界面できれいに剥離され、分離層１１０の表面（転写層１０３表面）に転写された凹凸部１０９が露出される。図６（ｂ）において圧縮空気６１５のみで剥離が進行しない場合は上方からスタンパ１００を持ち上げるようにすると、剥離をより効率良く行うことができる。
【００６６】
剥離された信号基板を多層光情報記録媒体として完成させるためには、さらに、図６の剥離工程のあとに、転写された凹凸部１０９の上にさらにスパッタリングにより信号記録層を形成したうえで、その上にさらに透明なカバー層（例えば厚み７５ミクロン）を均一に形成する必要がある。透明カバー層の形成方法は所望の透明カバー層の厚みより薄い厚み精度の高い透明フィルムを透明な接着剤で貼る方法や、透明なオーバコート剤で所望の厚みの層を直接形成する方法とがある。上記本実施の形態で説明した方法で作製された多層光情報記録媒体では、信号記録層の間を分離する分離層が均一になるため、記録及び再生を行っている信号記録層と隣接した信号記録層からの迷光等の影響がどの半径位置でも一定となり、安定な記録及び再生が可能であり、どの半径位置でも良質かつ安定な信号を得ることができる。
【００６７】
なお、本実施の形態では転写層と接着層としてともに紫外線硬化樹脂を用いたが、熱硬化性材料であっても良い。このとき、スタンパの材質は、例えば、ニッケル、鉄をはじめとする金属類、プラスチックであればＡＢＳ樹脂等の耐熱性の高いものを選ぶ必要がある。
【００６８】
また、図４ではスタンパ１００を信号基板１０５の上から重ねたが、スタンパ１００を下におき信号基板１０５を上から重ねても良い。また、信号基板１０５上に接着層用の紫外線硬化樹脂４０３を滴下したが、スタンパ１００上の転写層１０３に滴下してもよい。信号基板１０５とスタンパ１００のどちらを上から重ね合わせてもかまわない。また、接着層用の紫外線硬化樹脂４０３を信号基板１０５とスタンパ１００の両方に滴下してもかまわない。いずれの場合にも、接着層用の紫外線硬化樹脂と滴下する表面との塗れ性等を考えて、接着層の所望の厚み分布を得るように回転条件を決定すればよい。
【００６９】
（実施の形態２）
実施の形態２では、図４に示した接着層の形成方法と異なる第２の接着層形成工程について説明する。図７にその概念図を示す。図７（ａ）のように図４（ａ）と同様の方法にて回転テーブル７０１に信号基板１０５を保持して、リング状の紫外線硬化樹脂４０４を配置する。ただし、滴下位置は実施の形態１の場合より内側であり、半径１５ｍｍの位置である。接着層用の紫外線硬化樹脂は実施の形態１と同じものでかまわない。
【００７０】
次に図７（ｂ）のように、回転テーブル７０１を高速回転する。これにより信号基板１０５上には延伸された接着層４０５が形成される。回転条件は５０００ｒｐｍで２０ｓｅｃである。この条件であれば、図５（ａ）に示した厚み分布とほぼ同じものが得られる。次に図７（ｃ）に示すように、図３（ｃ）で得られた転写層１０３が形成されたスタンパ１００と接着層７０６の形成された信号基板１０５を減圧チャンバ７０５内に導入して減圧下で重ね合わせる。転写層１０３と接着層７０６が接するように重ね合わせる。減圧チャンバ７０５内には信号基板１０５を固定するテーブル７０２がある。テーブル７０２にはセンターピン７０３があり、上から重ねるスタンパ１００と固定された信号基板１０５と中心をあわせることができる。
【００７１】
減圧チャンバ７０５の内部は信号基板１０５とスタンパ１００が導入された後、真空ポンプ７０４で減圧される。減圧下で重ね合わせるため、転写層１０３と接着層７０６の間には気泡が混入することはない。重ね合わせた後、減圧チャンバ７０５内が大気開放されて空気を導入したのち、信号基板１０５とスタンパ１００を取り出し、図３（ｃ）のように紫外線ランプ２１０を用いて接着層７０６を硬化する。硬化後、図６に示した方法でスタンパ１００を剥離する。剥離後の工程は実施の形態１に示したものと同様なのでここでは省略する。
【００７２】
なお、実施の形態２では、信号基板１０５の上に接着層７０６を形成して、スタンパ１００と重ね合わせたが、転写層１０３の上に接着層７０６を形成して、接着層のない信号基板１０５と重ね合わせてもよい。また、信号基板１０５とスタンパ１００の両方に接着層を形成して重ね合わせてもよい。いずれの場合にも、接着層用の紫外線硬化樹脂と滴下する表面との塗れ性等を考えて、接着層の所望の厚み分布を得るように回転条件を決定すればよい。
【００７３】
また、図７（ｃ）に示した工程の後、減圧チャンバ７０５より重ね合わせされた信号基板１０５とスタンパ１００を取り出し、加圧チャンバ内に導入して、オートクレーブにより微小な気泡（内部は減圧空気）を潰してもよい。
【００７４】
（実施の形態３）
実施の形態３では、転写層の半径方向の厚み分布がスタンパの内周部で薄く外周になるにつれて徐々に厚くなる傾向であり、また、接着層の半径方向の厚み分布が信号基板の内周部で厚く外周になるにつれて徐々に薄くなる傾向である場合の例について説明する。転写層の形成は図７（ａ），（ｂ）と同様、接着層の形成は図２及び図３で示した方法とほぼ同じである。まず、図８を用いて工程概略を説明する。
【００７５】
第１に、転写層の形成である。図８（ａ）に示すように、回転テーブル７０１に固定したスタンパ１００に転写層用の紫外線硬化樹脂を滴下して、回転テーブル７０１を回転して紫外線硬化樹脂を延伸する。スタンパ１００は実施の形態１及び２で用いたものと同じものが使用できる。紫外線硬化樹脂としては、実施の形態１及び２と同じ樹脂でよい。滴下位置は半径１１ｍｍの位置である。回転は４０００ｒｐｍで回転時間は５ｓｅｃである。回転停止後、紫外線ランプにて延伸された転写層８０１を硬化する。図９（ａ）に延伸された転写層８０１の厚み分布を示す。内周部で８ミクロン、外周部で１０ミクロンと徐々に厚い傾向になっている。
【００７６】
次に、信号基板との接着である。図８（ｂ）に示すように、図２及び３で説明した方法と同様に回転テーブル２０１の上に信号記録膜１０６の形成された信号基板１０５を固定して、中心穴１０８を直径２２ｍｍの蓋２０２で塞いでノズル２０５より接着層用の紫外線硬化樹脂８０２を塗布する。紫外線硬化樹脂８０２を滴下しながら回転テーブル２０１を回転する。このとき、信号基板１０５は実施の形態１及び２と同様のものでよい。紫外線硬化樹脂８０２は、実施の形態１とは異なり２００ｍＰａ・ｓのアクリル樹脂である。樹脂の滴下時間は９ｓｅｃである。初期の６ｓｅｃは低速で、その後の回転数は２０００ｒｐｍであり、回転時間は１０ｓｅｃである。回転停止後、蓋２０２を除去する。得られた接着層８０４の厚み分布は図９（ｂ）のようなものである。内周部で１７ミクロン、外周部で１５〜１６ミクロンである。外周にかけて徐々に薄くなるように回転条件を制御したことになる。
【００７７】
最後に、紫外線硬化樹脂８０２を硬化することなく、信号基板１０５と硬化された転写層８０３が形成されたスタンパを、図８（ｃ）に示すような減圧チャンバ内に導入して、減圧下で重ね合わせる。減圧チャンバ７０５内は真空ポンプ７０４で減圧される。信号基板１０５の中心とスタンパ１００の中心はテーブル７０２のセンターピン７０３で合わされる。重ね合わせされた信号基板１０５とスタンパ１００に紫外線を照射して、接着層８０４を硬化する。硬化後、図６に示した方法でスタンパ１００を剥離する。得られた分離層（転写層と接着層からなる層）の厚み分布を図９（ｃ）に示す。転写層１０３と接着層８０４が各々半径方向の厚み分布が制御されているため、得られる分離層の厚み分布は２５．５±０．５ミクロンの範囲に入り非常に均一となる。
【００７８】
なお、剥離後の工程は実施の形態１に示したものと同様なのでここでは省略する。
【００７９】
また、実施の形態３では、接着層８０４を安定に作製するために信号基板１０５上に形成したが、スタンパ１００上の硬化された転写層８０３の上に形成して、接着層のない信号基板と重ね合わせてもよい。また、信号基板１０５上に接着層８０４を形成して蓋２０２を除去して硬化した上で、図８（ａ）の延伸された転写層８０１を硬化することなく、減圧チャンバ７０５内で重ね合わせてもよい。
【００８０】
この場合、重ねた後紫外線で延伸された転写層８０１を硬化するが、転写層用の紫外線硬化樹脂が硬化後の接着層との接着力が十分強いことが必須条件となる。さもなければ、剥離工程においてスタンパ１００と転写層との界面でうまく剥離ができなくなる。いずれの場合にも、塗布する転写層あるいは接着層の厚み分布が所望のものになるように回転条件を決定することが重要である。
【００８１】
また、図８（ｃ）の後、減圧チャンバ７０５より重ね合わせされた信号基板１０５とスタンパ１００を取り出し、加圧チャンバ内に導入して、オートクレーブにより微小な気泡（内部は減圧空気）を潰してもよい。
【００８２】
（実施の形態４）
実施の形態４では、転写層あるいは接着層が感圧性接着剤である場合について説明する。
【００８３】
第１の例は、転写層が上記実施の形態１〜３と同様、紫外線硬化樹脂であり、接着層が感圧性接着剤である場合である。転写層は実施の形態３の図８（ａ）と同様に形成する。図８（ａ）の方法は図２及び３で示した方法より蓋を用いないことから容易である。転写層用の紫外線硬化樹脂を実施の形態３と同じものを用いれば、厚み分布は図９（ａ）と同様になる。転写層の形成方法に関しては上記と同様であるため、省略する。接着層として感圧性接着剤を用いる場合、感圧性接着剤は予め円盤状にしておく必要がある。
【００８４】
感圧性接着剤の厚み分布は図９（ｂ）のように制御しておく必要がある。感圧性接着剤は半固体状のものであるため、一般的に厚み分布をコントロールしやすい。図１０に感圧性接着剤を接着層として用いたときの分離層の作製方法を示す。図１０（ａ）は信号基板１０５に感圧性接着剤１００５を貼り付ける方法を示している。感圧性接着剤１００５には中心穴１００６があり、また、内周から外周にかけて徐々に薄くなるような厚み分布を持たせてある。中心穴１００６があるため、固定テーブル１０００のセンターピン１００１により信号基板１０５の中心と合わすことができる。感圧性接着剤１００５は、ローラ１０１０により信号基板１０５の外周端より順に他方の外周端まで貼られる。ローラ１０１０は感圧性接着剤１００５とくっつかないような表面処理（例えばフッ化処理）が施されているゴムであることが望ましい。ゴム製であれば弾力性があるため、感圧性接着剤１００５と信号基板１０５の間には大気中でも気泡が混入しづらくなる。
【００８５】
この図１０（ａ）の工程は減圧チャンバ内で行ってもよい。ローラ１０１０を感圧性接着剤１００５へ押す圧力が十分高ければ、信号基板上の凹凸部に感圧性接着剤１００５を埋め込むことは可能である。また、感圧性接着剤１００５のローラ１０１０と接する面にローラ１０１０とのくっつきを防止する保護フィルムがあってもよい。図１０（ｂ）は硬化された転写層８０３が形成されたスタンパ１００と減圧チャンバ７０５内で重ね合わせされる様子を示す図である。手順は実施の形態２および３に示したものと同じである。感圧性接着剤１００５に保護フィルムがついている場合、この工程の前で剥がしておく必要があることは言うまでもない。重ね合わせた後、感圧性接着剤１００５に紫外線硬化性等の特長があり硬化することができるものの場合は硬化してもよい。最後に剥離工程を行い、厚み分布が均一な分離層を得ることができる。
【００８６】
第２の例は、転写層が紫外線硬化性のある感圧性接着剤であり、接着層が紫外線硬化樹脂である場合である。接着層は図７（ａ）および（ｂ）と同じである。ここでは、説明を省略する。図１１は転写層用の感圧性接着剤１１０５をバルーン１１００によりスタンパ１００に重ねる方法を示している。感圧性接着剤１１０５は内周から外周にかけて徐々に薄くなる厚み分布を有するように形成されている。図１１（ａ）に示すように、感圧性接着剤１１０５には中心穴１１０６があり、固定テーブル１０００のセンターピン１００１によりスタンパ１００の中心と合わされる。固定テーブル１０００の中心上方よりバルーン１１００を下ろし、徐々にエア１１０１を入れていく。バルーン１１００は感圧性接着剤１１０５とくっつかないような表面処理（例えばフッ化処理）が施されているゴムであることが望ましい。
【００８７】
バルーン１１００にエア１１０１を入れていくと、図１１（ｂ）のように弾力性のあるバルーン１１００は膨らみ、スタンパ１００の中心より外周端へと感圧性接着剤１１０５をスタンパ１００に接触させていく。バルーン１１００の弾力性と中心から徐々に感圧性接着剤１１０５をスタンパ１００に接触させることにより、感圧性接着剤１１０５とスタンパ１００の界面への気泡混入を防ぐことができる。また、感圧性接着剤１１０５はバルーン１１００で押されるため、スタンパ１００上の凹凸部１０２に埋め込まれる。この工程の後、紫外線照射により感圧性接着剤１１０５を硬化する。硬化することにより、剥離工程の際でも感圧性接着剤１１０５に形成された凹凸部１０２が変形したりすることはない。感圧性接着剤の硬化後、図７（ｃ）の方法と同様に信号基板と重ね合わせ接着層を硬化したのち、最後に剥離工程が行われる。
【００８８】
なお、実施の形態４では、接着層形成方法としてローラを、転写層形成方法としてバルーンを用いる場合を説明したが、接着層形成方法としてバルーンを、転写層形成方法としてローラを用いてもよい。
【００８９】
また、実施の形態４では、接着層あるいは転写層が感圧性接着剤である場合についてのみ説明したが、接着層と転写層両方が感圧性接着剤であってもよい。また、上記で説明した紫外線硬化樹脂の厚み分布が内周から外周にかけて徐々に薄くなるように制御して、感圧性接着剤の厚み分布を内周から外周にかけて徐々に厚くなるように制御してもよい。
【００９０】
以上までの説明における多層光情報記録媒体の製造方法および製造装置は、転写層と接着層を有する分離層の厚み分布を制御することができ、分離層の厚みを均一にすることができる。これにより、分離層を挟む信号記録層の記録および再生を安定に行うことができ、かつ良質な信号を得ることができる。また、分離層の厚みむらについて生産マージンを得ることができ、量産性を向上することができる。
【００９１】
このように製造された多層光情報記録媒体３００２の一例を図１４に示す。このように本発明の実施の形態による製造方法により製造された多層光情報記録媒体の断面を見ると、分離層１１０を構成する転写層１０３および接着層１０７の界面が中心から外側に向かって斜めになっており、分離層１１０は半径方向において一定の厚みを有することがわかる。この場合、斜めの程度は製造条件により様々であり、場合によってはこの界面が実質上水平であることもあり得る。
【００９２】
また、以上までの説明において、各転写層および各接着層の半径方向の厚み分布は、互いに補うように両者の厚み分布が制御されてもよいし、一方の層の厚み分布を他方の層の厚み分布を考慮しながら制御されてもよく、各転写層および各接着層の両者の厚みの合計が半径方向において均一であれば上記の場合と同様の効果を得ることができる。さらに、各転写層および各接着層の半径方向のそれぞれの厚み分布が均一であってもよい。
【００９３】
また、以上までの説明において、分離層は、各転写層および各接着層の２層から構成されるとしたが、分離層は、３層以上の複数の層から構成されていてもよい。その場合、例えば、分離層が３層から構成される場合、本発明の信号基板は、信号基板１０５および信号基板１０５上に形成された第ｎ−１層に対応する。そして、分離層がｍ層から構成される場合は、本発明の信号基板は、信号基板１０５と第１層から第ｎ−１層までが積層された層に対応する。図１５にそのような場合の信号基板の例を示す。
【００９４】
また、ｎ＋１層およびｎ層が形成されて、その一方の層の厚み分布の制御を他方の層の厚み分布を考慮しながら制御するのは、例えば、１つ前の製造ロットにおける厚み分布を考慮しながら、上記一方の層の厚み分布を制御する場合も含まれる。その場合、一番最初の製造ロットとして試作品における厚み分布を考慮しながら一方の厚み分布を制御する場合も考えられる。
【００９５】
また、上記の実施の形態１〜４では、分離層が１つしかない場合について説明したが、本発明はこの場合に限られず、分離層が複数存在してもよく、その場合は、複数ある分離層のうち少なくとも１つの分離層に対して適用され得る。
【００９６】
なお、実施の形態２及び３の場合と同様に、図１０（ｂ）の後、減圧チャンバ７０５より重ね合わせされた信号基板１０５とスタンパ１００を取り出し、加圧チャンバ内に導入して、オートクレーブにより微小な気泡（内部は減圧空気）を潰してもよい。
【００９７】
以上、上記実施の形態１〜４では、本発明の多層光情報記録媒体の製造方法の実施形態を主として説明したが、本発明の多層光情報記録媒体の製造装置は、図２〜４、図６〜８、図１０、１１に示す各工程で用いた回転テーブルやノズルといった構成部品を各手段として構成されている。
【００９８】
また、以上の説明においては、本発明の信号記録層は、信号記録膜１０６であるとしたが、本発明の信号記録層は、案内溝またはピットにより構成されていてもよい。
【００９９】
また、以上までの説明では、本発明の放射線硬化材料は紫外線硬化樹脂であるとして説明したが、それ以外の放射線により硬化される材料であってもよい。
【０１００】
【発明の効果】
以上のように、本発明の多層光情報記録媒体の製造方法及び製造装置は、分離層を挟む信号記録層への記録及び信号記録層からの再生を安定に行うことができ、良質な信号を得ることができる。
【図面の簡単な説明】
【図１】本発明の一実施の形態における多層光情報記録媒体の製造方法を示す模式図
【図２】本発明の一実施の形態の転写層形成工程における転写層の塗布方法の一例を示す図
【図３】本発明の一実施の形態の転写層形成工程における転写層の硬化方法の一例と得られた厚み分布を示す図
【図４】本発明の一実施の形態における接着層形成工程の一例を示す図
【図５】図２、図３及び図４の工程の結果得られた接着層と分離層の厚み分布を示す図
【図６】本発明の一実施の形態におけるスタンパの剥離工程の一例を示す図
【図７】本発明の一実施の形態における接着層形成工程の第２の例を示す図
【図８】本発明の一実施の形態における、厚み分布が図２ないし図７と異なる場合の転写層形成および接着層形成の方法を示す図
【図９】図８の形成方法で得られる厚み分布を示す図
【図１０】本発明の一実施の形態における、接着層として感圧性接着剤を用いた場合の接着層形成工程を示す図
【図１１】本発明の一実施の形態における、転写層として感圧性接着剤を用いた場合の転写層形成工程を示す図
【図１２】従来技術の多層光情報記録媒体の製造方法の一部を示す図
【図１３】従来技術により製造された多層光情報記録媒体の断面図
【図１４】本発明の実施の形態の製造方法により製造された多層光情報記録媒体の断面図
【図１５】本発明の実施の形態の変形例を示す図
【符号の説明】
１００　スタンパ
１０１、１０８、１００６、１１０６　中心穴
１０２　凹凸部
１０３　転写層
１０５　信号基板
１０６　信号記録膜
１０７、７０６、８０４　接着層
１０９　転写された凹凸部
１１０　分離層
２００、４０３、８０２　紫外線硬化樹脂
２０１、４０１、７０１　回転テーブル
２０２　蓋
２０５、４００　ノズル
２１０　紫外線ランプ
４０２、７０３、１００１　センターピン
４０４　リング状の紫外線硬化樹脂
４０５　延伸された接着層
６００　固定台
６０１　センターポスト
６０２　吹き出し口
６１０　くさび
６１５　圧縮空気
６２０　剥離前中間物
７０２　テーブル
７０４　真空ポンプ
７０５　減圧チャンバ
８０１　延伸された転写層
８０３　硬化された転写層
１０００　固定テーブル
１００５、１１０５　感圧性接着剤
１０１０　ローラ
１１００　バルーン
１１０１　エア[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for manufacturing a multilayer optical information recording medium that performs recording and reproduction from one side having a separation layer between a plurality of signal recording layers.
[0002]
[Prior art]
As a high-density optical information recording medium, a multilayer optical information recording medium having a plurality of signal recording surfaces in the thickness direction, such as a single-sided, dual-layer reproduction DVD, has been proposed. For example, in a single-sided dual-layer reproduction DVD, one information recording surface of two substrates is provided with a light-transmitting reflective layer such as gold or silicon, and the other information recording surface is formed of a conventional aluminum or other reflective layer. The layers are each formed into a film, and are bonded together such that their information recording surfaces are on the inside.
[0003]
Furthermore, in order to improve the areal recording density per layer, a blue-violet laser light source (wavelength around 400 nm) and a high NA lens are used, and a thin recording / reproducing side transparent cover layer having a thickness of 0.1 mm is used. A density optical information recording medium has been proposed. In this high-density optical information recording medium, signal guide grooves or pits were formed on the surface of a thick signal substrate, a rewritable recording multilayer film was formed thereon, and a transparent cover layer was further formed thereon. It has a structure. It is conceivable that this thin transparent cover layer type high-density optical information recording medium has two signal recording surfaces. One example of the manufacturing method is as follows.
[0004]
(1) On a thick substrate on which signal guide grooves or pits are formed on a surface and a rewritable recording multilayer film is formed, a separation layer is further formed by using an ultraviolet curing resin, and the separation layer is formed. A signal guide groove or pit for the second layer is formed on the surface.
[0005]
(2) A rewritable translucent recording multilayer film is formed on the second-layer signal guide groove or pit.
[0006]
(3) A thin recording / reproducing side transparent cover layer having a thickness of 0.1 mm is formed.
[0007]
As a specific manufacturing method (for example, see Patent Literature 1), a plastic stamper 2100 is used for the above-described step (1), and the first and second signal guide grooves or pits on the stamper 2100 are covered. An ultraviolet curing resin is applied and cured. Thereafter, using a second ultraviolet curing resin having different properties as an adhesive layer, the substrate on which the first signal recording layer 2106 is formed and the cured first ultraviolet curing resin are attached to each other. After the ultraviolet curing resin is cured, the stamper 2100 is peeled off. Thus, the separation layer 2110 is formed from the first ultraviolet curable resin and the second ultraviolet curable resin. According to such a method, a signal signal layer 2106 having a rigid thickness is used as a base, and another signal recording layer 2106 and a plurality of signal recording layers 2106 are stacked on the signal substrate 2105 via a separation layer 2110 to form a multilayer optical signal. An information recording medium can be manufactured.
[0008]
[Patent Document 1]
JP-A-2002-260307
[0009]
[Problems to be solved by the invention]
However, the thickness of the separation layer 2110 existing between the signal recording layers 2106 of the multilayer optical information recording medium needs to be uniform. If the thickness of the separation layer 2110 is uniform, one of the signal recording layers 2106 before and after the separation layer 2110 has a constant influence of light reflected from the other signal recording layer 2106 during recording or reproduction. When the reflected light from the other signal recording layer 2106 fluctuates, it becomes a disturbance component of the reproduced signal, and the S / N deteriorates. Conversely, if the thickness of the separation layer 2110 is uniform, disturbance from the other signal recording layer 2106 is constant, so that recording or reproduction becomes stable and the quality of a reproduction signal is improved.
[0010]
FIG. 12 shows a time change of the amount of the ultraviolet curable resin dropped onto the signal substrate 2105 or the stamper 2100 when the conventional multilayer optical information recording medium is manufactured, and the signal substrate 2105 or the stamper with the ultraviolet curable resin dropped. It is a figure which shows the rotation speed of 2100. As shown in FIG. 12, in the conventional manufacturing method, the ultraviolet curable resin is dropped near the central portion of the signal substrate 2105 or the stamper 2100, and after the dripping is completed, the signal substrate 2105 or the stamper 2100 is rotated to rotate the resin. The centrifugal force caused the ultraviolet curable resin to extend outward from near the center of the signal substrate 2105 or the stamper 2100.
[0011]
In the manufacturing method as described above, the thickness of the ultraviolet curable resin increases outside the center of the stamper 2100 or the signal substrate 2105 due to the centrifugal force when the stamper 2100 or the signal substrate 2105 rotates. Therefore, as shown in FIG. 13, the separation layer 2110 formed by combining ultraviolet curable resins having different properties also tends to increase in thickness from the center to the outside. The S / N ratio of the multilayer optical information recording medium was not satisfactory.
[0012]
The present invention has been made in view of the above-mentioned problems of the conventional manufacturing method, and has been made in view of the above-mentioned problems, and it is possible to stably perform recording on and reproduction from a signal recording layer sandwiching a separation layer, and obtain multilayer optical information capable of obtaining a high-quality signal. It is an object to provide a method and an apparatus for manufacturing a recording medium.
[0013]
[Means for Solving the Problems]
A first aspect of the present invention for solving the above-mentioned problem is a method for manufacturing a multilayer optical information recording medium, which performs recording and reproduction from one side having a separation layer between a plurality of signal recording layers,
(A) forming an (n + 1) th layer adjacent to a surface of a stamper on which a signal recording area having at least one of a guide groove and a pit is located;
(B) forming an n-th layer adjacent to a signal substrate having the signal recording layer;
The separation layer is obtained by combining the (n + 1) th layer and the nth layer,
A method for manufacturing a multilayer optical information recording medium, wherein a radial thickness distribution of at least one of the (n + 1) th layer and the nth layer is formed or controlled based on a radial thickness distribution of the other layer. .
[0014]
The (n + 1) th layer is formed with a predetermined thickness distribution, the nth layer is formed with a predetermined thickness distribution,
A first method of manufacturing a multilayer optical information recording medium according to the present invention, wherein the thickness distribution of at least one layer in the radial direction is controlled in consideration of the thickness distribution of the other layer in the radial direction.
[0015]
According to a second aspect of the present invention, the (n + 1) th layer and the nth layer are formed with a predetermined thickness distribution,
A first method of manufacturing a multilayer optical information recording medium according to the present invention, wherein the thickness distribution of at least one layer in the radial direction is controlled in consideration of the thickness distribution of the other layer in the radial direction.
[0016]
According to the first or second method of manufacturing a multilayer optical information recording medium of the present invention, the thickness distribution in the radial direction of one of the (n + 1) th layer and the nth layer is controlled in consideration of the other. , The thickness distribution of the separation layer having both can be controlled and made uniform. As a result, recording and reproduction of the signal recording layer sandwiching the separation layer can be performed stably, and a high-quality signal can be obtained.
[0017]
A third aspect of the present invention is the method for manufacturing a multilayer optical information recording medium according to the first or second aspect of the present invention, wherein a radial thickness distribution of the separation layer is substantially uniform.
[0018]
According to the third method of manufacturing a multilayer optical information recording medium of the present invention, since the thickness distribution in both the (n + 1) th layer and the nth layer in the radial direction is controlled, the thickness distribution of the separation layer having both is also controlled. And can be uniform. As a result, recording and reproduction of the signal recording layer sandwiching the separation layer can be performed stably, and a high-quality signal can be obtained.
[0019]
A fourth aspect of the present invention is the method for manufacturing a multilayer optical information recording medium according to the first aspect of the present invention, further comprising a step of removing the stamper from the (n + 1) th layer.
[0020]
According to a fifth aspect of the present invention, the thickness distribution in the radial direction of the (n + 1) th layer is thinner in the outer peripheral portion than the inner peripheral portion of the stamper, and the thickness distribution in the radial direction of the nth layer is smaller than the inner thickness of the signal substrate. This is the first method for manufacturing a multilayer optical information recording medium of the present invention, in which the outer peripheral portion is thicker than the peripheral portion. According to the above manufacturing method, the separation layer having the (n + 1) th layer and the nth layer can be made uniform.
[0021]
In a sixth aspect of the present invention, the (n + 1) -th layer is a radiation-curable material, and the step (a) includes the step of forming the radiation-curable material on an inner peripheral portion of the stamper or an inner peripheral portion of the n-th layer of the signal substrate. A fifth method of manufacturing a multi-layer optical information recording medium according to the present invention, comprising a step of dropping a material and a step of rotating the stamper or the signal substrate onto which the radiation-curable material has been dropped.
[0022]
The seventh invention is characterized in that after the step of rotating the stamper or the signal substrate on which the radiation curing material is dropped,
Performing a step of superimposing the stamper and the signal substrate with the (n + 1) th layer being inside;
Thereafter, a step of irradiating the radiation-curable material by irradiating the radiation is performed, which is the sixth method for producing a multilayer optical information recording medium of the present invention.
[0023]
According to an eighth aspect of the present invention, the step (a) comprises a step of dropping the radiation-curable material onto an inner peripheral portion of the stamper or an inner peripheral portion of the n-th layer; A method of manufacturing a multilayer optical information recording medium according to a sixth aspect of the present invention, comprising a step of rotating a stamper or the signal substrate. According to the above manufacturing method, the (n + 1) th layer can be easily formed.
[0024]
According to a ninth aspect of the present invention, a step of dropping the radiation-curable material onto an inner peripheral portion of the stamper or an inner peripheral portion of the n-th layer of the signal substrate includes the step of: dropping the radiation-curable material onto the stamper or the signal substrate. A method of manufacturing a multilayer optical information recording medium according to any one of the sixth to eighth aspects, wherein a part of the rotating step is performed simultaneously. According to the above manufacturing method, the thickness distribution in the radial direction of the (n + 1) th layer can be easily controlled.
[0025]
A tenth aspect of the present invention is the sixth to eighth aspects, wherein the stamper or the signal substrate is rotated while dropping the radiation-curable material onto the inner periphery of the stamper or the inner periphery of the n-th layer of the signal substrate. It is a method for manufacturing a multilayer optical information recording medium according to any one of the present invention.
[0026]
An eleventh aspect of the present invention provides the method according to the eleventh aspect, wherein the radiation-curable material is dropped on an inner peripheral portion of the stamper or an n-th layer of the signal substrate. The method according to any one of the sixth to eighth aspects of the present invention, wherein, when there is a center hole, the radiation-curable material is dropped on the cover after covering the center hole. is there. According to the above manufacturing method, the thickness distribution in the radial direction of the (n + 1) th layer can be easily controlled.
[0027]
According to a twelfth aspect of the present invention, the thickness distribution in the radial direction of the (n + 1) th layer is thicker in the outer peripheral portion than in the inner peripheral portion of the stamper, and the thickness distribution in the radial direction of the nth layer is within the signal substrate. This is the first method for manufacturing a multilayer optical information recording medium of the present invention, in which the outer peripheral portion is thinner than the peripheral portion. According to the above configuration, the separation layer having the (n + 1) th layer and the nth layer can be made uniform.
[0028]
A thirteenth aspect of the present invention is that the n-th layer is a radiation-curable material, and the step (b) is performed by forming the radiation-curable material on the inner periphery of the (n + 1) -th layer of the stamper or the inner periphery of the signal substrate. A step of dropping a material, a step of rotating the stamper or the signal substrate on which the radiation-curable material is dropped, and such that the surface of the stamper and the signal substrate on which the radiation-curable material is applied faces inside after rotation. A method of manufacturing a multilayer optical information recording medium according to the twelfth aspect of the present invention, comprising the steps of: superimposing on a substrate; and irradiating radiation to cure the radiation-curable material. According to the above manufacturing method, the stamper on which the (n + 1) th layer is formed and the signal substrate can be easily bonded.
[0029]
A fourteenth aspect of the present invention is a step of dropping the radiation-curable material on the inner periphery of the stamper or the inner periphery of the signal substrate, and rotating the stamper or the signal substrate on which the radiation-curable material is dropped. A thirteenth method of manufacturing a multilayer optical information recording medium according to the present invention, wherein a part of the method is performed simultaneously. According to the above manufacturing method, the thickness distribution in the radial direction of the n-th layer can be easily controlled.
[0030]
A fifteenth aspect of the present invention is the method for manufacturing a multilayer optical information recording medium according to the fourteenth aspect of the present invention, which rotates while dropping the radiation-curable material onto the inner periphery of the stamper or the inner periphery of the signal substrate.
[0031]
Sixteenth invention, before dropping the radiation-curable material, if there is a center hole at the approximate center of the stamper or the signal board, after covering the center hole, A thirteenth to a fifteenth method of manufacturing a multilayer optical information recording medium according to the present invention, wherein a radiation-curable material is dropped. According to the above manufacturing method, the thickness distribution in the radial direction of the n-th layer can be easily controlled.
[0032]
A seventeenth aspect of the present invention is the multilayer optical information according to the seventh or thirteenth aspect, wherein the step of superimposing the radiation-curable material on the stamper or the signal substrate so that the surface to which the radiation-curable material is applied is inside is performed under a reduced pressure environment. This is a method for manufacturing a recording medium. According to the above manufacturing method, it is possible to prevent air bubbles from being mixed into the separation layer.
[0033]
An eighteenth aspect of the present invention is the method for manufacturing the multilayer optical information recording medium according to the fifth or twelfth aspect of the present invention, wherein the (n + 1) th layer contains a radiation-curable pressure-sensitive adhesive. According to the above-mentioned manufacturing method, the pressure-sensitive adhesive has a high viscosity, so that the thickness distribution can be easily controlled and the transfer of a signal from the stamper can be ensured.
[0034]
The nineteenth invention is the method for producing a multilayer optical information recording medium according to the fifth or twelfth invention, wherein the n-th layer contains a pressure-sensitive adhesive. According to the above manufacturing method, the pressure-sensitive adhesive has a high viscosity, so that the thickness distribution of the n-th layer can be easily controlled.
[0035]
In a twentieth aspect of the present invention, the n-th layer is a radiation-curable material, and the step (b) comprises the step of: bonding the radiation-curable material for forming the n-th layer to the (n + 1) -th layer of the stamper. A step of dropping the stamper and at least one of the signal substrates, and overlapping the stamper and the signal substrate such that the (n + 1) th layer is on the inside, and rotating the stamper and the signal substrate to cure the bonding radiation. A fifth method of producing a multilayer optical information recording medium according to the present invention, comprising a step of stretching a material and a step of irradiating radiation to cure the radiation-curable material. According to the above-described manufacturing method, the bubbles in the n-th layer are blown off without stretching even if the pressure is reduced, so that the inclusion of bubbles can be prevented.
[0036]
According to a twenty-first aspect of the present invention, the (n + 1) -th layer is a radiation-curable material, and the step (a) includes transferring the radiation-curable material for forming the (n + 1) -th layer onto the stamper and the signal substrate. Dropping onto at least one of the n-th layer, overlapping the stamper and the signal substrate such that the n-th layer is on the inside, and rotating the stamper and the signal substrate to cure the transfer radiation. A twelfth method for producing a multilayer optical information recording medium according to the present invention, comprising a step of stretching a material and a step of irradiating radiation to cure the radiation-curable material.
[0037]
A twenty-second aspect of the present invention is an apparatus for manufacturing a multilayer optical information recording medium that performs recording and reproduction from one side having a separation layer between a plurality of signal recording layers,
When forming the separation layer on the signal recording layer, a thickness distribution in a radial direction of the stamper is formed on a surface of the stamper on which a signal recording region having at least one of a guide groove and a pit exists. An (n + 1) th layer forming means for controlling to form an (n + 1) th layer;
Forming an n-th layer whose thickness distribution in the radial direction is controlled between the (n + 1) th layer on the stamper and the signal substrate having the signal recording layer, and forming the (n + 1) th layer on the stamper and the Bonding means for bonding the signal board;
A multilayer optical information recording device, comprising: a peeling unit that peels off the stamper from the (n + 1) th layer and obtains the separation layer having the (n + 1) th layer and the (n) th layer on which a signal on the stamper is transferred. It is an apparatus for manufacturing a medium.
[0038]
According to the apparatus for manufacturing a multilayer optical information recording medium of the present invention, the thickness distribution of both the (n + 1) th layer and the (n) th layer in the radial direction is controlled. It can be expected that the productivity can be improved by improving the yield. In addition, recording and reproduction of the signal recording layer sandwiching the separation layer can be performed stably, and a high-quality signal can be obtained.
[0039]
In a twenty-third aspect of the present invention, when the (n + 1) th layer is a radiation curing material,
Dropping means for dropping the radiation-curable material onto the inner periphery of the stamper, rotating means for rotating the stamper onto which the radiation-curable material has been dropped, and curing means for curing the radiation-curable material by irradiating radiation A twenty-second manufacturing apparatus for a multilayer optical information recording medium according to the present invention, comprising: According to the above configuration, the (n + 1) th layer can be easily formed.
[0040]
A twenty-fourth aspect of the present invention is the apparatus for manufacturing a multilayer optical information recording medium according to the twenty-third aspect of the present invention, wherein the stamper is rotated while dropping the radiation-curable material onto the inner periphery of the stamper.
[0041]
Twenty-fifth aspect of the present invention is that, before the radiation-curable material is dropped on the inner peripheral portion of the stamper, if there is a center hole substantially at the center of the stamper, the center hole is covered, and A twenty-third or a twenty-fourth manufacturing apparatus for a multilayer optical information recording medium according to the present invention, wherein the radiation-curable material is dropped from above. According to the above configuration, the radial thickness distribution of the (n + 1) th layer can be easily controlled.
[0042]
A twenty-sixth aspect of the present invention provides a method as described above, wherein the n-th layer is a radiation-curable material,
Dropping means for dropping the radiation-curable material onto the inner periphery of the (n + 1) th layer or the signal substrate of the stamper, and rotating means for rotating the stamper or the signal substrate onto which the radiation-curable material has been dropped. And a stacking unit for stacking the stamper and the signal substrate after rotation so that the surface of the signal substrate on which the radiation-curable material is applied is inside, and a curing unit for curing the radiation-curable material by irradiating radiation. It is a twenty-second apparatus for manufacturing a multilayer optical information recording medium according to the present invention. According to the above configuration, the stamper on which the (n + 1) th layer is formed and the signal substrate can be easily bonded.
[0043]
A twenty-seventh aspect of the present invention is the apparatus for manufacturing a multilayer optical information recording medium according to the twenty-sixth aspect of the present invention, which rotates while dripping the radiation-curable material onto the inner periphery of the stamper or the inner periphery of the signal substrate.
[0044]
Twenty-eighth aspect of the present invention is that, before dropping the radiation-curable material, when the stamper or the signal board has a center hole substantially at the center thereof, the center hole is covered, and A twenty-sixth or twenty-seventh invention for manufacturing a multilayer optical information recording medium of the present invention, wherein a radiation-curable material is dropped. According to the above configuration, the radial thickness distribution of the n-th layer can be easily controlled.
[0045]
A twenty-ninth aspect of the present invention is a multi-layer optical information recording medium according to the twenty-sixth aspect of the present invention, wherein the superimposing means has a decompression means, and the stamper and the signal substrate are superimposed on each other after the surroundings are set to a decompressed environment. Manufacturing equipment. According to the above configuration, it is possible to prevent air bubbles from being mixed into the separation layer, and an improvement in yield can be expected.
[0046]
In a thirtieth aspect of the present invention, when the n-th layer is a radiation curing material,
Dropping means for dropping an adhesive radiation-curable material for forming the n-th layer on at least one of the n + 1-th layer and the signal substrate of the stamper; and applying the stamper and the signal substrate to the n + 1-th layer. Have a stretching means for rotating the stamper and the signal substrate to stretch the radiation curing material for bonding, and a curing means for curing the radiation curing material by irradiating radiation. A twenty-second embodiment is an apparatus for manufacturing a multilayer optical information recording medium according to the present invention. According to the above configuration, the air bubbles in the n-th layer are blown off by stretching even if the pressure is not reduced, so that mixing of air bubbles can be prevented, and an improvement in yield can be expected.
[0047]
A thirty-first aspect of the present invention provides a substrate layer capable of having signal information,
An n-th layer formed on the substrate layer;
An (n + 1) th layer formed on the nth layer;
A protective layer formed above the (n + 1) th layer, wherein the combined thickness of the nth and (n + 1) th layers is uniform.
[0048]
A thirty-second aspect of the present invention is the multilayer optical information recording medium according to the thirty-first aspect, wherein the radial thickness of the (n + 1) th layer and the radial thickness of the nth layer are opposite to each other.
[0049]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0050]
(Embodiment 1)
This embodiment will be described with reference to FIG. Here, the thickness distribution in the radial direction of the transfer layer, which is an example of the (n + 1) th layer of the present invention, tends to be thicker at the inner peripheral portion of the stamper (mold) and gradually thinner toward the outer periphery. An example in which the thickness distribution in the radial direction of the adhesive layer, which is an example of the n-layer, tends to be thinner at the inner peripheral portion of the signal substrate and gradually increased toward the outer periphery.
[0051]
FIG. 1 shows a conceptual diagram of the present invention. First, as shown in FIG. 1A, the transfer layer 103 is formed on the concave and convex portions 102 on the surface of the stamper 100 having a circular shape. The uneven portion 102 formed in the signal recording area has at least one of a guide groove and a pit. For example, a groove having a track pitch of 0.32 μm and a depth of 20 nm having wobbles indicating address information can be given. Further, a center hole 101 may be provided at the center of the stamper 100. The transfer layer 103 is formed so as to have a thickness distribution that is thicker at the inner peripheral portion with respect to the radial direction of the stamper 100 and gradually becomes thinner toward the outer peripheral portion.
[0052]
Next, as shown in FIG. 1B, a signal recording film 106, which is an example of a signal recording layer of the present invention, is provided on the surface of the signal substrate 105. An adhesive layer 107 is formed between the surface of the signal substrate 105 on which the signal recording film 106 is provided and the stamper 100 on which the transfer layer 103 is formed, and the stamper 100 and the signal substrate 105 are adhered. The signal board 105 may have a center hole 108. Here, the adhesive layer 107 is formed so as to have a thickness distribution that is thinner in the inner peripheral portion in the radial direction and gradually becomes thicker in the outer peripheral portion. Since the thickness distributions of the transfer layer 103 and the adhesive layer 107 in the radial direction are opposite to each other, the thickness distribution of the two separation layers 110 is uniform. Finally, as shown in FIG. 1C, the stamper 100 is peeled off from the interface with the transfer layer 103. An uneven portion 109 transferred from the stamper 100 is formed on the surface of the transfer layer 103. The transfer layer 103 is a layer for transferring the concave and convex portions 102 on the stamper 100, and it is necessary to appropriately select each material so as to facilitate separation at the interface between the transfer layer 103 and the stamper 100.
[0053]
As described above, the separation layer 110 having a uniform thickness in the radial direction is obtained. After the signal recording film 3001 is formed on the transferred uneven portion 109 of the separation layer 110, a separation layer or a protection layer 3000 is further formed. The above is the outline of the present invention. Note that the signal substrate 105 may have another signal recording layer below the signal recording film 106 (not shown). That is, the signal recording film 106 may be formed on the separation layer.
[0054]
Hereinafter, each step of FIGS. 1A to 1C will be described in detail.
[0055]
First, the step of forming the transfer layer will be described using an example. FIGS. 2 and 3 show a case where a transfer layer is formed by spin coating using an ultraviolet curable resin as an example of the radiation curable material of the present invention as a material of the transfer layer. A stamper 100 having a center hole 101 as shown in FIG. 2A is prepared. The diameter of the center hole 101 is 15 mm, and the outer diameter of the stamper 100 is 120 mm. Here, since an ultraviolet curable resin is used as the material of the transfer layer, the material of the stamper is preferably a plastic that is transparent to some extent to ultraviolet rays, such as an acrylic resin, an olefin resin, a polycarbonate, and a norbornene resin.
[0056]
Next, as shown in FIG. 2B, the stamper 100 is placed on the turntable 201. The rotary table 201 fixes the stamper 100 by a method such as vacuum suction. Then, the center hole 101 is covered with the lid 202. The outer shape of the lid 202 may be in the range of 15 mm to 42 mm in diameter, but here is 22 mm in diameter. The nozzle 205 is arranged on the lid 202, and the ultraviolet curable resin 200, which is the material of the transfer layer, is started to be dropped. Before dropping, the turntable 201 may be rotating. The ultraviolet curable resin 200 has a viscosity of 150 mPa · s. As shown in FIG. 1C, it is necessary to select a material that easily peels off at the interface with the stamper 100, as shown in FIG. For example, an acrylic material or the like that causes radical polymerization by irradiation with ultraviolet rays may be used. The resin dripping time is 9 sec. Almost simultaneously with the dropping, the turntable 201 is rotated as shown in FIG. The initial 6 sec is a low speed, and the rotation speed thereafter is 2000 rpm, and the rotation time at 2000 rpm is 10 sec. Therefore, the rotation is continued for 7 seconds after the end of the dropping. After the rotation, the turntable 201 stops.
[0057]
FIG. 3 shows the steps after stopping. FIG. 3A shows a state immediately after stopping. The thickness tends to be thicker on the inner periphery of the stamper and gradually thinner on the outer periphery. FIG. 3B shows the thickness of the transfer layer in the radial direction. It is about 15 microns thick at a radius of about 20 mm, but becomes thinner as it moves away from the center in the radial direction, and becomes about 13 microns at a point 58 mm radially from the center. Such a thickness distribution can be controlled by the dripping time of the ultraviolet curable resin, the number of rotations of the rotary table at the time of dripping, and the rotation time after stopping dripping. As the number of rotations and the rotation time increase, the change in thickness distribution in the radial direction decreases and becomes uniform as a whole.
[0058]
Finally, as shown in FIG. 3C, the cover 202 is removed from the stamper 100, and then the ultraviolet curing resin 200 is cured by the ultraviolet lamp 210 to obtain the transfer layer 103. The purpose of removing the lid 202 before curing is to prevent the ultraviolet curable resin 200 from solidifying after curing and making it difficult to remove the lid 202. The lid 202 may be removed by a robot arm, or a part of the lid may be made of a magnetic material and lifted using a magnet. Although the curing is performed on the rotary table 201 in FIG. 3C, the curing may be performed by moving the stamper 100 to a different table provided with an ultraviolet lamp. As the ultraviolet lamp 210, a metal halide lamp, a mercury lamp, a xenon lamp, or the like can be used.
[0059]
Next, a step of forming an adhesive layer will be described using an example. Here, a case where an ultraviolet curable resin is used as the adhesive layer will be described. As the ultraviolet curable resin, it is necessary to select a material for the signal substrate, a material for the signal recording layer, and a material having a strong adhesive force to the transfer layer 103. For example, an acrylic material may be used. FIG. 4 shows a case where the adhesive layer is stretched by spinning. As shown in FIG. 4A, first, the signal substrate 105 on which the signal recording film 106 is formed is arranged and fixed on the turntable 401. The outer diameter of the signal board 105 is 120 mm in diameter, the center hole 108 is 15 mm in diameter, and the material is plastic such as polycarbonate, acrylic, or olefin. The signal recording film 106 may be, for example, a phase change film such as GeSbTe or AgInSbTe, a recording film such as a magnetic film or a dye film, a dielectric film such as ZnS sandwiching them, a metal reflection film, or the like. Generally, a film is formed by sputtering or vapor deposition.
[0060]
The fixing to the turntable 401 is performed by vacuum suction at the contact surface with the signal board 105. The rotary table 401 has a center pin 402 that fits into the center hole 108, and the signal board 105 is centered. The rotating table 401 is rotated, and the ultraviolet curable resin 403 is dropped from the nozzle 400 disposed at a position on the signal substrate 105 with a radius of 20 to 30 mm. Here, an acrylic resin having a viscosity of 450 mPa · s is used as the ultraviolet curing resin 403. Since the signal substrate 105 is rotated, the ultraviolet curable resin 403 has a ring shape.
[0061]
Next, the stamper 100 obtained from the steps shown in FIGS. 2 and 3 is overlaid on the signal substrate 105. As shown in FIG. 4B, a ring-shaped ultraviolet curable resin 404 is formed on the signal substrate 105, and the stamper 100 is overlaid so that the transfer layer 103 contacts the ring-shaped ultraviolet curable resin 404 from above. Match. Since the center hole 101 of the stamper 100 has a diameter of 15 mm, the center hole 101 is fitted with the center pin 402 so that the signal board 105 and the center of the stamper 100 are aligned with each other. The superposition may be performed under a reduced pressure environment in order to prevent bubbles which may be mixed when the transfer layer 103 and the ring-shaped ultraviolet curable resin 404 come into contact with each other.
[0062]
Next, as shown in FIG. 4C, the rotary table 401 is rotated at a high speed, and the ultraviolet curable resin is stretched over the entire surface. Here, the rotation is performed at a high speed of 5000 rpm for 30 seconds. Thus, a stretched adhesive layer 405 is formed between the transfer layer 103 and the signal substrate 105. In order to perform stable peeling in the subsequent peeling step, it is necessary to prevent the stretched adhesive layer 405 from directly contacting the stamper 100 as shown in FIG. After the stretching, similarly to FIG. 3C, the adhesive layer 405 stretched from the stamper 100 side by an ultraviolet lamp is cured. Since the stamper 100 is transparent, it can be cured.
[0063]
FIG. 5 shows the thickness distribution of the obtained adhesive layer and the thickness distribution of the separation layer including the transfer layer and the adhesive layer. As shown in FIG. 5A, the thickness distribution of the adhesive layer is 10 μm at the inner periphery and gradually increases toward the outer periphery and becomes 12.5 μm at the outer periphery due to centrifugal force caused by high-speed rotation. The thickness distribution of the separation layer composed of the transfer layer and the adhesive layer is shown in FIG. 5 (b), which is the sum of FIGS. 3 (b) and 5 (a), and 24.5 ± from the inner circumference to the outer circumference. It is in the range of 0.5 microns and is very uniform.
[0064]
Finally, FIG. 6 shows a stamper peeling step. Here, a peeling method using a wedge and compressed air is described. As shown in FIG. 6A, the pre-peeling intermediate 620 to which the stamper 100 and the signal substrate 105 obtained in the bonding step are bonded is fixed on the fixing base 600. The fixing method is preferably vacuum suction. The fixed base 600 has a center post 601, and a blowout port 602 is provided in a part thereof.
[0065]
Next, as shown in FIG. 6B, the wedge 610 is taken out from the center post 601 and inserted into the interface between the stamper 100 and the transfer layer 103. At this time, the transfer layer 103 may be slightly displaced by the wedge 610. After the wedge 610 is inserted, compressed air 615 is blown out from the outlet 602. The compressed air 615 enters the interface between the stamper 100 into which the wedge 610 is inserted and the transfer layer 103, and starts to peel off the stamper 100. After waiting for a while, as shown in FIG. 6C, the stamper 100 is cleanly peeled off at the interface of the transfer layer 103, and the uneven portion 109 transferred to the surface of the separation layer 110 (the surface of the transfer layer 103) is exposed. In FIG. 6B, when the peeling does not proceed only with the compressed air 615, the peeling can be performed more efficiently by lifting the stamper 100 from above.
[0066]
In order to complete the peeled signal substrate as a multilayer optical information recording medium, further, after the peeling step of FIG. 6, after further forming a signal recording layer on the transferred uneven portion 109 by sputtering, Further, a transparent cover layer (for example, a thickness of 75 microns) needs to be uniformly formed thereon. The method of forming the transparent cover layer includes a method in which a transparent film having a thickness accuracy smaller than the desired thickness of the transparent cover layer is attached with a transparent adhesive, and a method in which a layer having a desired thickness is directly formed with a transparent overcoat agent. is there. In the multilayer optical information recording medium manufactured by the method described in the present embodiment, since the separation layer separating the signal recording layers is uniform, the signal adjacent to the signal recording layer performing recording and reproduction is used. The effect of stray light or the like from the recording layer is constant at any radial position, stable recording and reproduction are possible, and good quality and stable signals can be obtained at any radial position.
[0067]
In this embodiment, an ultraviolet curable resin is used for both the transfer layer and the adhesive layer. However, a thermosetting material may be used. At this time, as the material of the stamper, it is necessary to select a metal having high heat resistance, such as a metal such as nickel and iron, and an ABS resin if it is a plastic.
[0068]
In FIG. 4, the stamper 100 is stacked from above the signal board 105. However, the stamper 100 may be placed below and the signal board 105 may be stacked from above. Further, the ultraviolet curing resin 403 for the adhesive layer is dropped on the signal substrate 105, but may be dropped on the transfer layer 103 on the stamper 100. Either the signal board 105 or the stamper 100 may be overlaid from above. Further, the ultraviolet curing resin 403 for the adhesive layer may be dropped on both the signal substrate 105 and the stamper 100. In any case, the rotation conditions may be determined so as to obtain a desired thickness distribution of the adhesive layer in consideration of the wettability between the ultraviolet curable resin for the adhesive layer and the surface to be dropped.
[0069]
(Embodiment 2)
In the second embodiment, a second adhesive layer forming step different from the method for forming the adhesive layer shown in FIG. 4 will be described. FIG. 7 shows a conceptual diagram thereof. As shown in FIG. 7A, the signal substrate 105 is held on the turntable 701 in the same manner as in FIG. 4A, and the ring-shaped ultraviolet curable resin 404 is arranged. However, the dropping position is inside of the case of the first embodiment, and is a position with a radius of 15 mm. The UV-curable resin for the adhesive layer may be the same as in the first embodiment.
[0070]
Next, as shown in FIG. 7B, the rotary table 701 is rotated at a high speed. As a result, a stretched adhesive layer 405 is formed on the signal substrate 105. The rotation condition is 5000 rpm for 20 seconds. Under these conditions, a thickness distribution substantially the same as that shown in FIG. Next, as shown in FIG. 7C, the stamper 100 on which the transfer layer 103 obtained in FIG. 3C is formed and the signal substrate 105 on which the adhesive layer 706 is formed are introduced into the decompression chamber 705. Overlap under reduced pressure. The transfer layer 103 and the adhesive layer 706 are overlapped so as to be in contact with each other. Inside the decompression chamber 705, there is a table 702 for fixing the signal substrate 105. The table 702 has a center pin 703 so that the center of the stamper 100 and the signal board 105 fixed thereto can be aligned.
[0071]
After the signal substrate 105 and the stamper 100 are introduced into the decompression chamber 705, the pressure is reduced by the vacuum pump 704. Since the layers are superposed under reduced pressure, no air bubbles are mixed between the transfer layer 103 and the adhesive layer 706. After the superposition, the inside of the decompression chamber 705 is opened to the atmosphere and air is introduced. Thereafter, the signal substrate 105 and the stamper 100 are taken out, and the adhesive layer 706 is cured using the ultraviolet lamp 210 as shown in FIG. After curing, the stamper 100 is peeled off by the method shown in FIG. The steps after the peeling are the same as those described in Embodiment Mode 1, and thus are omitted here.
[0072]
In the second embodiment, the adhesive layer 706 is formed on the signal substrate 105 and overlapped with the stamper 100. However, the adhesive layer 706 is formed on the transfer layer 103, and the signal substrate without the adhesive layer is formed. 105 may be superimposed. Further, an adhesive layer may be formed on both the signal substrate 105 and the stamper 100 and may be overlapped. In any case, the rotation conditions may be determined so as to obtain a desired thickness distribution of the adhesive layer in consideration of the wettability between the ultraviolet curable resin for the adhesive layer and the surface to be dropped.
[0073]
After the step shown in FIG. 7C, the superposed signal substrate 105 and the stamper 100 are taken out from the decompression chamber 705, introduced into the pressurization chamber, and minute air bubbles (the inside is decompressed air) by an autoclave. ) May be crushed.
[0074]
(Embodiment 3)
In the third embodiment, the thickness distribution in the radial direction of the transfer layer tends to become thinner in the inner peripheral portion of the stamper and gradually increase as it goes to the outer periphery, and the thickness distribution in the radial direction of the adhesive layer changes to the inner peripheral portion of the signal substrate. An example will be described in which the thickness of the portion is thicker and the outer periphery is gradually thinner. The formation of the transfer layer is substantially the same as that shown in FIGS. 7A and 7B, and the formation of the adhesive layer is substantially the same as the method shown in FIGS. First, an outline of the process will be described with reference to FIG.
[0075]
First is the formation of a transfer layer. As shown in FIG. 8A, an ultraviolet curable resin for a transfer layer is dropped on the stamper 100 fixed to the rotary table 701, and the rotary table 701 is rotated to stretch the ultraviolet curable resin. The same stamper 100 as that used in the first and second embodiments can be used. As the ultraviolet curable resin, the same resin as in the first and second embodiments may be used. The drop position is a position with a radius of 11 mm. The rotation is 4000 rpm and the rotation time is 5 seconds. After the rotation is stopped, the transfer layer 801 stretched by an ultraviolet lamp is cured. FIG. 9A shows the thickness distribution of the transferred transfer layer 801. The thickness tends to gradually increase to 8 microns at the inner periphery and 10 microns at the outer periphery.
[0076]
Next, adhesion to a signal substrate is performed. As shown in FIG. 8B, the signal substrate 105 on which the signal recording film 106 is formed is fixed on the turntable 201 in the same manner as described with reference to FIGS. With the lid 202 closed, an ultraviolet curable resin 802 for an adhesive layer is applied from the nozzle 205. The rotating table 201 is rotated while the ultraviolet curable resin 802 is dropped. At this time, the signal board 105 may be the same as in the first and second embodiments. Unlike the first embodiment, the ultraviolet curing resin 802 is an acrylic resin of 200 mPa · s. The resin dripping time is 9 sec. The initial 6 sec is a low speed, the rotation speed thereafter is 2000 rpm, and the rotation time is 10 sec. After the rotation stops, the lid 202 is removed. The thickness distribution of the obtained adhesive layer 804 is as shown in FIG. It is 17 microns at the inner periphery and 15-16 microns at the outer periphery. This means that the rotation conditions were controlled so that the thickness gradually decreased toward the outer periphery.
[0077]
Finally, without curing the ultraviolet curing resin 802, the stamper on which the signal substrate 105 and the cured transfer layer 803 are formed is introduced into a decompression chamber as shown in FIG. Overlap. The pressure inside the decompression chamber 705 is reduced by the vacuum pump 704. The center of the signal board 105 and the center of the stamper 100 are aligned by the center pin 703 of the table 702. The superposed signal substrate 105 and the stamper 100 are irradiated with ultraviolet rays to cure the adhesive layer 804. After curing, the stamper 100 is peeled off by the method shown in FIG. FIG. 9C shows the thickness distribution of the obtained separation layer (a layer composed of the transfer layer and the adhesive layer). Since the thickness distribution in the radial direction of each of the transfer layer 103 and the adhesive layer 804 is controlled, the thickness distribution of the obtained separation layer falls within the range of 25.5 ± 0.5 μm and is very uniform.
[0078]
Note that the steps after peeling are the same as those described in Embodiment Mode 1, and thus are omitted here.
[0079]
In the third embodiment, the adhesive layer 804 is formed on the signal substrate 105 in order to stably produce the signal substrate. However, the signal substrate without the adhesive layer is formed on the cured transfer layer 803 on the stamper 100. May be superimposed. Further, after the adhesive layer 804 is formed on the signal substrate 105, the lid 202 is removed and cured, the stretched transfer layer 801 in FIG. 8A is superposed in the decompression chamber 705 without being cured. You may.
[0080]
In this case, the transfer layer 801 that has been stretched with ultraviolet rays after being stacked is cured, and it is an essential condition that the ultraviolet curing resin for the transfer layer has a sufficiently strong adhesive force with the adhesive layer after curing. Otherwise, in the peeling step, peeling cannot be performed well at the interface between the stamper 100 and the transfer layer. In any case, it is important to determine the rotation conditions so that the thickness distribution of the transfer layer or the adhesive layer to be applied becomes a desired one.
[0081]
After FIG. 8C, the signal substrate 105 and the stamper 100 which are superimposed on each other are taken out from the decompression chamber 705, and introduced into the pressurization chamber. Is also good.
[0082]
(Embodiment 4)
In the fourth embodiment, a case where the transfer layer or the adhesive layer is a pressure-sensitive adhesive will be described.
[0083]
The first example is a case where the transfer layer is an ultraviolet curable resin and the adhesive layer is a pressure-sensitive adhesive as in the first to third embodiments. The transfer layer is formed in the same manner as in Embodiment 3 shown in FIG. The method of FIG. 8A is easier than the method shown in FIGS. 2 and 3 because a lid is not used. If the same ultraviolet curing resin as that of the third embodiment is used for the transfer layer, the thickness distribution becomes the same as that of FIG. The method for forming the transfer layer is the same as that described above, and will not be described. When a pressure-sensitive adhesive is used as the adhesive layer, the pressure-sensitive adhesive needs to have a disk shape in advance.
[0084]
It is necessary to control the thickness distribution of the pressure-sensitive adhesive as shown in FIG. Since the pressure-sensitive adhesive is semi-solid, it is generally easy to control the thickness distribution. FIG. 10 shows a method for forming a separation layer when a pressure-sensitive adhesive is used as an adhesive layer. FIG. 10A shows a method of attaching the pressure-sensitive adhesive 1005 to the signal substrate 105. The pressure-sensitive adhesive 1005 has a center hole 1006 and has a thickness distribution such that the thickness gradually decreases from the inner periphery to the outer periphery. Since there is the center hole 1006, the center pin 1001 of the fixed table 1000 can be aligned with the center of the signal board 105. The pressure-sensitive adhesive 1005 is applied by the roller 1010 from the outer peripheral end of the signal board 105 to the other outer peripheral end. The roller 1010 is desirably rubber that has been subjected to a surface treatment (for example, fluoridation treatment) so as not to stick to the pressure-sensitive adhesive 1005. Since rubber is elastic, it is difficult for air bubbles to mix between the pressure-sensitive adhesive 1005 and the signal substrate 105 even in the air.
[0085]
This step of FIG. 10A may be performed in a reduced pressure chamber. If the pressure for pressing the roller 1010 against the pressure-sensitive adhesive 1005 is sufficiently high, it is possible to embed the pressure-sensitive adhesive 1005 in the uneven portion on the signal board. In addition, a protective film for preventing sticking to the roller 1010 may be provided on a surface of the pressure-sensitive adhesive 1005 which is in contact with the roller 1010. FIG. 10B is a diagram showing a state where the cured transfer layer 803 is superimposed on the stamper 100 on which the transfer layer 803 is formed in the decompression chamber 705. The procedure is the same as that shown in the second and third embodiments. Needless to say, if the pressure-sensitive adhesive 1005 has a protective film, it must be peeled off before this step. After overlapping, if the pressure-sensitive adhesive 1005 has a characteristic such as ultraviolet curability and can be cured, it may be cured. Finally, a separation step is performed to obtain a separation layer having a uniform thickness distribution.
[0086]
The second example is a case where the transfer layer is an ultraviolet-curable pressure-sensitive adhesive and the adhesive layer is an ultraviolet-curable resin. The adhesive layer is the same as in FIGS. 7A and 7B. Here, the description is omitted. FIG. 11 shows a method of stacking a pressure-sensitive adhesive 1105 for a transfer layer on a stamper 100 by a balloon 1100. The pressure-sensitive adhesive 1105 is formed so as to have a thickness distribution that gradually decreases from the inner periphery to the outer periphery. As shown in FIG. 11A, the pressure-sensitive adhesive 1105 has a center hole 1106, which is aligned with the center of the stamper 100 by the center pin 1001 of the fixed table 1000. The balloon 1100 is lowered from above the center of the fixed table 1000, and air 1101 is gradually introduced. The balloon 1100 is desirably a rubber that has been subjected to a surface treatment (for example, a fluoridation treatment) so as not to stick to the pressure-sensitive adhesive 1105.
[0087]
When air 1101 is introduced into the balloon 1100, the elastic balloon 1100 expands as shown in FIG. 11B, and the pressure-sensitive adhesive 1105 is brought into contact with the stamper 100 from the center of the stamper 100 to the outer peripheral end. . By gradually bringing the pressure-sensitive adhesive 1105 into contact with the stamper 100 from the center of the elasticity of the balloon 1100, air bubbles can be prevented from entering the interface between the pressure-sensitive adhesive 1105 and the stamper 100. Further, since the pressure-sensitive adhesive 1105 is pressed by the balloon 1100, it is embedded in the uneven portion 102 on the stamper 100. After this step, the pressure-sensitive adhesive 1105 is cured by ultraviolet irradiation. By curing, the uneven portion 102 formed on the pressure-sensitive adhesive 1105 does not deform even during the peeling step. After the pressure-sensitive adhesive is cured, the adhesive layer is superposed on the signal substrate and cured in the same manner as in the method of FIG. 7C, and finally, a peeling step is performed.
[0088]
In the fourth embodiment, a case where a roller is used as a method of forming an adhesive layer and a balloon is used as a method of forming a transfer layer, but a balloon may be used as a method of forming an adhesive layer, and a roller may be used as a method of forming a transfer layer.
[0089]
In the fourth embodiment, only the case where the adhesive layer or the transfer layer is a pressure-sensitive adhesive has been described, but both the adhesive layer and the transfer layer may be a pressure-sensitive adhesive. Also, the thickness distribution of the ultraviolet curing resin described above is controlled so as to gradually decrease from the inner periphery to the outer periphery, and the thickness distribution of the pressure-sensitive adhesive is controlled so as to gradually increase from the inner periphery to the outer periphery. Is also good.
[0090]
The method and apparatus for manufacturing a multilayer optical information recording medium described above can control the thickness distribution of the separation layer having the transfer layer and the adhesive layer, and can make the thickness of the separation layer uniform. Thereby, recording and reproduction of the signal recording layer sandwiching the separation layer can be performed stably, and a high-quality signal can be obtained. Further, a production margin can be obtained for the thickness unevenness of the separation layer, and mass productivity can be improved.
[0091]
FIG. 14 shows an example of the multilayer optical information recording medium 3002 manufactured as described above. Looking at the cross section of the multilayer optical information recording medium manufactured by the manufacturing method according to the embodiment of the present invention, the interface between the transfer layer 103 and the adhesive layer 107 constituting the separation layer 110 is inclined from the center to the outside. It can be seen that the separation layer 110 has a constant thickness in the radial direction. In this case, the degree of obliqueness varies depending on the manufacturing conditions, and in some cases, this interface may be substantially horizontal.
[0092]
Further, in the above description, the thickness distribution in the radial direction of each transfer layer and each adhesive layer may be controlled so that the thickness distribution of both layers is complemented with each other, or the thickness distribution of one layer may be changed to the other layer. The control may be performed in consideration of the thickness distribution. If the total thickness of both the transfer layer and the adhesive layer is uniform in the radial direction, the same effect as in the above case can be obtained. Further, the thickness distribution of each transfer layer and each adhesive layer in the radial direction may be uniform.
[0093]
In the above description, the separation layer is composed of two layers of each transfer layer and each adhesive layer. However, the separation layer may be composed of three or more layers. In that case, for example, when the separation layer is composed of three layers, the signal substrate of the present invention corresponds to the signal substrate 105 and the (n-1) th layer formed on the signal substrate 105. When the separation layer is composed of m layers, the signal substrate of the present invention corresponds to a layer in which the signal substrate 105 and the first to (n-1) th layers are stacked. FIG. 15 shows an example of a signal board in such a case.
[0094]
In addition, the reason why the thickness distribution of one layer is controlled while considering the thickness distribution of the other layer when the n + 1 layer and the n layer are formed is to consider, for example, the thickness distribution in the immediately preceding manufacturing lot. However, the case where the thickness distribution of the one layer is controlled is also included. In this case, one thickness distribution may be controlled while considering the thickness distribution of the prototype as the first production lot.
[0095]
Further, in the above-described first to fourth embodiments, the case where there is only one separation layer has been described. However, the present invention is not limited to this case, and a plurality of separation layers may be present. It can be applied to at least one of the separation layers.
[0096]
As in the case of Embodiments 2 and 3, after FIG. 10B, the signal board 105 and the stamper 100 which are superimposed are taken out from the decompression chamber 705, introduced into the pressurization chamber, and autoclaved. You may crush small air bubbles (the inside is decompressed air).
[0097]
As described above, in the first to fourth embodiments, the embodiment of the method for manufacturing a multilayer optical information recording medium of the present invention has been mainly described. Components such as rotary tables and nozzles used in the respective steps shown in FIGS. 6 to 8 and FIGS.
[0098]
Further, in the above description, the signal recording layer of the present invention is the signal recording film 106, but the signal recording layer of the present invention may be constituted by guide grooves or pits.
[0099]
Further, in the above description, the radiation curable material of the present invention is described as an ultraviolet curable resin, but may be a material curable by other radiation.
[0100]
【The invention's effect】
As described above, the method and apparatus for manufacturing a multilayer optical information recording medium of the present invention can stably perform recording on and reproduction from the signal recording layer sandwiching the separation layer, and provide a high-quality signal. Obtainable.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a method for manufacturing a multilayer optical information recording medium according to an embodiment of the present invention.
FIG. 2 is a diagram showing an example of a transfer layer coating method in a transfer layer forming step according to one embodiment of the present invention.
FIG. 3 is a diagram showing an example of a method of curing a transfer layer in a transfer layer forming step according to an embodiment of the present invention, and a thickness distribution obtained.
FIG. 4 is a diagram showing an example of an adhesive layer forming step in one embodiment of the present invention.
FIG. 5 is a view showing a thickness distribution of an adhesive layer and a separation layer obtained as a result of the processes of FIGS. 2, 3, and 4;
FIG. 6 is a diagram showing an example of a stamper peeling step according to one embodiment of the present invention.
FIG. 7 is a diagram showing a second example of the adhesive layer forming step in one embodiment of the present invention.
FIG. 8 is a diagram showing a method of forming a transfer layer and an adhesive layer when the thickness distribution is different from those in FIGS. 2 to 7 in one embodiment of the present invention.
FIG. 9 is a view showing a thickness distribution obtained by the forming method of FIG. 8;
FIG. 10 is a diagram showing an adhesive layer forming step when a pressure-sensitive adhesive is used as the adhesive layer in one embodiment of the present invention.
FIG. 11 is a diagram showing a transfer layer forming step when a pressure-sensitive adhesive is used as the transfer layer in one embodiment of the present invention.
FIG. 12 is a diagram showing a part of a method for manufacturing a multilayer optical information recording medium according to the related art.
FIG. 13 is a cross-sectional view of a multilayer optical information recording medium manufactured by a conventional technique.
FIG. 14 is a sectional view of a multilayer optical information recording medium manufactured by the manufacturing method according to the embodiment of the present invention;
FIG. 15 is a diagram showing a modification of the embodiment of the present invention.
[Explanation of symbols]
100 stamper
101,108,1006,1106 center hole
102 Uneven part
103 transfer layer
105 signal board
106 signal recording film
107, 706, 804 adhesive layer
109 Transferred irregularities
110 Separation layer
200, 403, 802 UV curable resin
201, 401, 701 rotary table
202 lid
205, 400 nozzles
210 UV lamp
402, 703, 1001 Center pin
404 Ring-shaped UV curable resin
405 Stretched adhesive layer
600 fixed base
601 Center Post
602 outlet
610 wedge
615 Compressed air
620 Intermediate before peeling
702 table
704 vacuum pump
705 decompression chamber
801 Stretched transfer layer
803 Hardened transfer layer
1000 fixed table
1005, 1105 Pressure sensitive adhesive
1010 roller
1100 balloon
1101 air

Claims

Performing recording and reproduction from one side having a separation layer between a plurality of signal recording layers, a method for manufacturing a multilayer optical information recording medium,
(A) forming an (n + 1) th layer adjacent to a surface of a stamper on which a signal recording area having at least one of a guide groove and a pit is located;
(B) forming an n-th layer adjacent to a signal substrate having the signal recording layer;
The separation layer is obtained by combining the (n + 1) th layer and the nth layer,
A method for manufacturing a multilayer optical information recording medium, wherein a radial thickness distribution of at least one of the (n + 1) th layer and the nth layer is formed or controlled based on a radial thickness distribution of the other layer.

Forming the (n + 1) th layer and the (n) th layer each having a predetermined thickness distribution;
2. The method according to claim 1, wherein the thickness distribution of at least one layer in the radial direction is controlled in consideration of the thickness distribution of the other layer in the radial direction.

3. The method for manufacturing a multilayer optical information recording medium according to claim 1, wherein the radial thickness distribution of the separation layer is substantially uniform.

The method for manufacturing a multilayer optical information recording medium according to claim 1, further comprising a step of peeling off the stamper from the (n + 1) th layer.

The thickness distribution in the radial direction of the (n + 1) th layer is thinner in the outer peripheral portion than in the inner peripheral portion of the stamper, and the thickness distribution in the radial direction of the nth layer is smaller in the outer peripheral portion than the inner peripheral portion of the signal board. The method for manufacturing a multilayer optical information recording medium according to claim 1, wherein the thickness is thick.

Wherein the (n + 1) th layer is a radiation-curable material, and the step (a) comprises dropping the radiation-curable material onto an inner peripheral portion of the stamper or an inner peripheral portion of the n-th layer of the signal substrate; 6. The method for manufacturing a multilayer optical information recording medium according to claim 5, comprising: rotating the stamper or the signal substrate on which the radiation curable material has been dropped.

After the step of rotating the stamper or the signal substrate on which the radiation curing material has been dropped,
Performing a step of superimposing the stamper and the signal substrate with the (n + 1) th layer being inside;
7. The method for manufacturing a multilayer optical information recording medium according to claim 6, wherein a step of irradiating the radiation-curable material by irradiating radiation is performed thereafter.

The step (a) is a step of dropping the radiation-curable material onto the inner periphery of the stamper or the inner periphery of the n-th layer, and rotating the stamper or the signal substrate on which the radiation-curable material is dropped. 7. The method for manufacturing a multilayer optical information recording medium according to claim 6, comprising the steps of:

Part of the step of dropping the radiation-curable material onto the inner periphery of the stamper or the inner periphery of the n-th layer of the signal substrate, and the step of rotating the stamper or the signal substrate onto which the radiation-curable material has been dropped 9. The method for manufacturing a multilayer optical information recording medium according to claim 6, wherein the steps are performed simultaneously.

The multilayer according to any one of claims 6 to 8, wherein the stamper or the signal substrate is rotated while dropping the radiation-curable material onto an inner peripheral portion of the stamper or an inner peripheral portion of the n-th layer of the signal substrate. A method for manufacturing an optical information recording medium.

Before dropping the radiation-curable material on the inner periphery of the stamper or the inner periphery of the n-th layer of the signal substrate, if there is a center hole substantially at the center of the n-th layer of the stamper or the signal substrate, The method for manufacturing a multilayer optical information recording medium according to any one of claims 6 to 8, wherein the radiation curable material is dropped from above the lid after covering the center hole.

The thickness distribution in the radial direction of the (n + 1) th layer is thicker in the outer periphery than in the inner periphery of the stamper, and the thickness distribution in the radial direction of the nth layer is larger in the outer periphery than the inner periphery of the signal board. The method for manufacturing a multilayer optical information recording medium according to claim 1, wherein the thickness is thin.

The n-th layer is a radiation-curable material, and the step (b) is a step of dropping the radiation-curable material onto an inner peripheral portion of the (n + 1) -th layer of the stamper or an inner peripheral portion of the signal substrate; Rotating the stamper or the signal substrate onto which the radiation-curable material has been dropped, and superposing the stamper and the signal substrate after rotation so that the surface of the signal-cured material coated with the radiation-curable material is inside, Irradiating the radiation-curable material to cure the radiation-curable material.

Part of the step of dropping the radiation-curable material onto the inner periphery of the stamper or the inner periphery of the signal substrate and the step of rotating the stamper or the signal substrate onto which the radiation-curable material has been dropped are simultaneously performed. The method for manufacturing a multilayer optical information recording medium according to claim 13, wherein

The method for manufacturing a multilayer optical information recording medium according to claim 14, wherein the rotation is performed while dropping the radiation curable material onto an inner peripheral portion of the stamper or an inner peripheral portion of the signal substrate.

Before dropping the radiation-curable material, if the stamper or the signal substrate has a center hole substantially at the center thereof, the center hole is covered, and the radiation-curable material is dropped from above the lid. A method for manufacturing a multilayer optical information recording medium according to claim 13.

14. The method for manufacturing a multilayer optical information recording medium according to claim 7, wherein the step of superimposing the stamper or the signal substrate so that the surface of the signal curing substrate coated with the radiation curable material is inside is performed under a reduced pressure environment.

13. The method according to claim 5, wherein the (n + 1) th layer contains a radiation-curable pressure-sensitive adhesive.

The method for manufacturing a multilayer optical information recording medium according to claim 5, wherein the n-th layer includes a pressure-sensitive adhesive.

The n-th layer is a radiation-curable material, and in the step (b), the bonding radiation-curable material for forming the n-th layer is coated on the (n + 1) -th layer of the stamper and the signal substrate. Dropping at least one of them, overlapping the stamper and the signal substrate such that the (n + 1) th layer is on the inside, rotating the stamper and the signal substrate, and stretching the bonding radiation-curable material; And curing the radiation-curable material by irradiating the radiation-curable material.

The (n + 1) th layer is a radiation-curable material, and the step (a) includes transferring the radiation-curable material for transfer for forming the (n + 1) th layer on the stamper and the signal substrate on the n-th layer. A step of dropping at least one of them, a step of superimposing the stamper and the signal substrate such that the n-th layer is on the inside, and a step of rotating the stamper and the signal substrate to extend the transfer radiation-curable material; Irradiating the radiation-curable material to cure the radiation-curable material.

Performing recording and reproduction from one side having a separation layer between a plurality of signal recording layers, a multilayer optical information recording medium manufacturing apparatus,
When forming the separation layer on the signal recording layer, a thickness distribution in a radial direction of the stamper is formed on a surface of the stamper on which a signal recording region having at least one of a guide groove and a pit exists. An (n + 1) th layer forming means for controlling to form an (n + 1) th layer;
Forming an n-th layer whose thickness distribution in the radial direction is controlled between the (n + 1) th layer on the stamper and the signal substrate having the signal recording layer, and forming the (n + 1) th layer on the stamper and the Bonding means for bonding the signal board;
A multilayer optical information recording device, comprising: a peeling unit that peels off the stamper from the (n + 1) th layer and obtains the separation layer having the (n + 1) th layer and the (n) th layer on which a signal on the stamper is transferred. Media manufacturing equipment.

When the (n + 1) th layer is a radiation curing material,
Dropping means for dropping the radiation-curable material onto the inner periphery of the stamper, rotating means for rotating the stamper onto which the radiation-curable material has been dropped, and curing means for curing the radiation-curable material by irradiating radiation 23. The apparatus for manufacturing a multilayer optical information recording medium according to claim 22, comprising:

24. The apparatus for manufacturing a multilayer optical information recording medium according to claim 23, wherein the stamper is rotated while dropping the radiation curable material onto an inner peripheral portion of the stamper.

Before dropping the radiation-curable material onto the inner periphery of the stamper, if the stamper has a center hole substantially at the center, then cover the center hole with the radiation-curable material from above the lid. 25. The apparatus for manufacturing a multilayer optical information recording medium according to claim 23, wherein the apparatus is dropped.

When the n-th layer is a radiation-curable material, the bonding means:
Dropping means for dropping the radiation-curable material onto the inner peripheral portion of the (n + 1) th layer or the signal substrate of the stamper, and rotating means for rotating the stamper or the signal substrate onto which the radiation-curable material has been dropped. And a stacking means for stacking the stamper and the signal substrate after rotation so that the surface of the signal substrate coated with the radiation-curable material is on the inside, and a curing means for curing the radiation-curable material by irradiating radiation. 23. The apparatus for manufacturing a multilayer optical information recording medium according to claim 22, comprising:

27. The apparatus for manufacturing a multilayer optical information recording medium according to claim 26, wherein the apparatus rotates while dripping the radiation curable material onto an inner peripheral portion of the stamper or an inner peripheral portion of the signal substrate.

Before dropping the radiation-curable material, if the stamper or the signal substrate has a center hole substantially at the center thereof, the center hole is covered, and the radiation-curable material is dropped from above the lid. An apparatus for manufacturing a multilayer optical information recording medium according to claim 26 or 27.

27. The apparatus for manufacturing a multilayer optical information recording medium according to claim 26, wherein the superimposing means has a decompressing means, and the stamper and the signal substrate are superimposed on each other after a decompression environment is set around the depressurizing means.

When the n-th layer is a radiation-curable material, the bonding means:
Dropping means for dropping an adhesive radiation-curable material for forming the n-th layer on at least one of the n + 1-th layer and the signal substrate of the stamper; and applying the stamper and the signal substrate to the n + 1-th layer. Have a stretching means for rotating the stamper and the signal substrate to stretch the radiation curing material for bonding, and a curing means for curing the radiation curing material by irradiating radiation. An apparatus for manufacturing a multilayer optical information recording medium according to claim 22.

A substrate layer capable of having signal information;
An n-th layer formed on the substrate layer;
An (n + 1) th layer formed on the nth layer;
A protective layer formed above the (n + 1) th layer, wherein the combined thickness of the nth and (n + 1) th layers is uniform.

32. The multilayer optical information recording medium according to claim 31, wherein a radial thickness of the (n + 1) th layer and a radial thickness of the nth layer are opposite to each other.