JP3602652B2 - Optical information recording medium, information recording method and information reproducing method for optical information recording medium - Google Patents

Description

（ただし，Ｘ ¹ 〜Ｘ ⁴ は，それぞれ独立に水素原子，ハロゲン原子，置換基を有しても良いアルキル基，置換基を有しても良いアリール基，置換基を有しても良いアルコキシ基，置換基を有しても良いアリールオキシ基，置換基を有しても良いアルキルチオ基，置換基を有しても良いアリールチオ基，ニトロ基，シアノ基，スルホン酸基，スルホン酸アミド基，スルホン酸エステル基であり，ｏ，ｐ，ｑ，ｒは，置換基Ｘ ¹ 〜Ｘ ⁴ の置換数で０〜４の整数である。）で表されるフタロシアニン化合物であり，前記色素が，外部エネルギーの付加によって凝集状態が変化し，複数の異なる波長域に対する吸収スペクトルが変化するものである。
【００２４】
また，本発明の請求項２に係る光情報記録媒体は，請求項１記載の光情報記録媒体において，前記記録層が，前記色素の凝集状態の変化により，前記色素の凝集状態の変化前の反射率と比較して，前記複数の異なる波長域から選択された全ての光に対する反射率を低下させることによって情報を記録及び再生するものである。
【００２５】
また，本発明の請求項３に係る光情報記録媒体は，請求項１又は２記載の光情報記録媒体において，前記複数の異なる波長域が，６２０〜６５０ｎｍ及び７６０〜８３０ｎｍであるものである。
【００２６】
また，本発明の請求項４に係る光情報記録媒体は，請求項３記載の光情報記録媒体において，前記６２０〜６５０ｎｍの波長域から選択された波長のレーザ光で情報の記録及び再生が可能であり，かつ前記７６０〜８３０ｎｍの波長域から選択された波長のレーザ光で情報の記録及び再生が可能であるものである。
【００２７】
また，本発明の請求項５に係る光情報記録媒体は，請求項４記載の光情報記録媒体において，更に，前記６２０〜６５０ｎｍ又は前記７６０〜８３０ｎｍのいずれか一方の波長域から選択された波長のレーザ光によって記録された情報が，前記６２０〜６５０ｎｍ及び前記７６０〜８３０ｎｍの波長域から選択された全ての波長のレーザ光で再生可能であるものである。
【００２９】
また，本発明の請求項６に係る光情報記録媒体の情報記録方法は，請求項１〜５のいずれかに記載の光情報記録媒体の情報記録方法において，前記記録層に対して外部エネルギーを付加して，前記色素の凝集状態を変化させ，前記複数の異なる波長域の吸収スペクトルを，前記外部エネルギー付加前の吸収スペクトルから異なる吸収スペクトルに変化させることによって前記記録層に情報を記録するものである。
【００３０】
また，本発明の請求項７に係る光情報記録媒体の情報記録方法は，請求項６記載の光情報記録媒体の情報記録方法において，前記複数の異なる波長域から選択された全ての波長の光に対する反射率を，前記吸収スペクトル変化前の反射率から低下させることによって前記記録層に情報を記録するものである。
【００３１】
また，本発明の請求項８に係る光情報記録媒体の情報記録方法は，請求項６又は７記載の光情報記録媒体の情報記録方法において，前記複数の異なる波長域が，６２０〜６５０ｎｍ及び７６０〜８３０ｎｍであるものである。
【００３２】
また，本発明の請求項９に係る光情報記録媒体の情報再生方法は，請求項１〜５のいずれかに記載の光情報記録媒体の情報再生方法において，前記外部エネルギーを付加することによって吸収スペクトルが変化する複数の異なる波長域から選択された光を用いて，前記記録層に記録された情報を再生するものである。
【００３３】
また，本発明の請求項１０に係る光情報記録媒体の情報再生方法は，請求項９記載の光情報記録媒体の情報再生方法において，前記記録層に前記複数の異なる波長域から選択された光を照射してその反射光を受光し，前記記録層に情報が記録されていない状態の反射率に対する反射率の低下を検出することによって前記記録層に記録された情報を再生するものである。
【００３４】
更に，本発明の請求項１１に係る光情報記録媒体の情報再生方法は，請求項９又は１０記載の光情報記録媒体の情報再生方法において，前記複数の異なる波長域が，６２０〜６５０ｎｍ及び７６０〜８３０ｎｍであるものである。
【００３５】
すなわち，本発明に係る光情報記録媒体は，複数の異なる波長域から選択されたレーザ光で情報の記録及び再生を可能にすることを特徴とする。複数の異なる波長域から選択されたレーザ光とは，例えば異なる波長域が２つの場合，一方のレーザ光の記録波長λ_ｗ ^１ と他方の記録波長λ_ｗ ^２ ，一方のレーザ光の再生波長λ_ｒ ^１ と他方の再生波長λ_ｒ ^２ がそれぞれ異なっていても良いということである。すなわち，λ_ｗ ^１ ≠λ_ｗ ^２ ≠λ_ｒ ^１ ≠λ_ｒ ^２ でも良い。通常，記録波長と再生波長は同一波長を用いるため，λ_ｗ ^１ ＝λ_ｒ ^１ ≠λ_ｗ ^２ ＝λ_ｒ ^２ となる。
【００３６】
また，本発明に係る光情報記録媒体は，ある１つの波長のレーザ光で記録した情報を２つ以上の異なる波長のレーザ光で再生可能とすることである。例えば，異なる記録波長及び再生波長がそれぞれ２つずつある場合には，λ_ｗ ^１ 又はλ_ｗ ^２ で記録した情報を，λ_ｒ ^１ 及びλ_ｒ ^２ のいずれを用いても再生することができる。
【００３７】
具体的に，本発明に係る光情報記録媒体は，７６０〜８３０ｎｍの波長域から選択された波長のレーザ光で情報を記録でき，その記録された情報を，７６０〜８３０ｎｍの波長域から選択された波長のレーザ光で再生でき（記録波長と再生波長は異なっていても良い），かつ６２０〜６５０ｎｍの波長域から選択された波長のレーザ光で情報を記録でき，その記録された情報を，６２０〜６５０ｎｍの波長域から選択された波長のレーザ光で再生できるものである（記録波長と再生波長は異なっていても良い）。加えて，７６０〜８３０ｎｍの波長域から選択された波長のレーザ光で記録された情報を，この波長域とは異なる波長域，例えば６２０〜６５０ｎｍの波長域から選択された波長のレーザ光で再生することができる。更に，６２０ｎｍ〜６５０ｎｍの波長域から選択された波長のレーザ光で記録された情報を，この波長域とは異なる波長域，例えば７６０〜８３０ｎｍの波長域から選択されたレーザ光で再生することができる。
【００３８】
本発明に係る光情報記録媒体では，７６０〜８３０ｎｍ及び６２０〜６５０ｎｍの波長域から選択された波長のレーザ光で情報を記録することにより，７６０〜８３０ｎｍ及び６２０〜６５０ｎｍ近傍の吸収スペクトルを変化させることができる。そして，情報は，７６０〜８３０ｎｍ及び６２０〜６５０ｎｍの波長域から選択された波長のレーザ光を照射した場合の反射率を，情報が記録されていない状態での反射率に対して低下させることによって記録される。
【００３９】
これにより，６２０〜６５０ｎｍの波長域から選択された波長のレーザ光を照射し，受光した反射光の反射率の低下を検出することによって，７６０〜８３０ｎｍの波長域から選択された波長のレーザ光によって記録された情報を再生することができる。また，７６０〜８３０ｎｍの波長域から選択された波長のレーザ光を照射し，受光した反射光の反射率の低下を検出することによって，６２０〜６５０ｎｍの波長域から選択された波長のレーザ光によって記録された情報を再生することができる。
【００４０】
このようにある波長のレーザ光を照射し，複数の波長域の吸収スペクトルを変化させ，かつ複数の波長域から選択された波長のレーザ光に対する反射率を低下させることができることが，本発明の光情報記録媒体の特徴である。吸収スペクトルの変化は，記録層の色素の凝集状態の変化によって起こる。本発明の発明者は，色素の凝集状態を変化させて６２０〜６５０ｎｍ及び７６０〜８３０ｎｍの波長域の吸収スペクトルを変化させ，かつ反射率を低下させることができる色素を見い出した。その色素の構造は，上記化学式に示されるものである。
【００４１】
また，本発明に係る光情報記録媒体の情報記録方法では，外部エネルギーで上記色素分子の凝集状態を制御し，吸収スペクトルを変化させる。吸収スペクトルの変化としては，色素の相変化や結晶化による吸光度の増減，色素吸光度の増減である濃色効果（ｈｙｐｅｒｃｈｒｏｍｉｃ ｅｆｆｅｃｔ）や淡色効果（ｈｙｐｏｃｈｒｏｍｉｃ ｅｆｆｅｃｔ），又は吸収スペクトルのシフトが生じる凝集状態の変化や深色移動（ｂａｔｈｏｃｈｒｏｍｉｃ ｓｈｉｆｔ），浅色移動（ｈｙｐｓｏｃｈｒｏｍｉｃ ｓｈｉｆｔ）等がある。
【００４２】
吸収スペクトルの形状変化は，吸収スペクトルのどのような変化であっても良いが，色素の分解，溶解，相変化，結晶化等により，色素膜の物理的形状変化を伴うものは従来技術の問題点で説明したように好ましくない。
【００４３】
そこで，本発明では，色素の凝集状態のみを変化させて吸収スペクトルを変化させるという方法を用いる。この吸収スペクトルの変化は，いわゆる吸収スペクトルのシフトを伴う。ただし，吸収スペクトルの変化により，吸収スペクトルシフトのみが生じるわけではない。ここでスペクトルシフトという用語を用いたのは，図２２に示すような記録層等の形状変化を伴わない記録を行うことができるということを強調したものである。言い換えれば，色素を含む記録層の物理的変化を伴わない吸収スペクトル変化が生じるということを意味している。以下に使用される吸収スペクトルシフト又は吸収スペクトルの変化という用語は，全て色素の形状状態等の物理的変化を伴わない吸収スペクトルの変化という意味として用いる。ただし，本発明に用いられる記録層は形状状態等の物理的変化を伴わない吸収スペクトルの変化により情報を記録／再生できるが，実際の光ディスクにおいて図２２に示したような基板等の物理的変化が本発明の吸収スペクトルの変化に付加されることを拒むものではない。要は本発明の光情報記録媒体の記録層は，従来のように基板等の物理的変化がなくても全くかまわないのである。
【００４４】
本発明の光情報記録媒体では，前記吸収スペクトルシフトを少なくとも２つ以上の異なる波長域で同時に起こさせることで情報の記録を行う。この吸収スペクトルシフトとは，１つの外部エネルギーの付与，例えばある波長のレーザ光の照射によって吸収スペクトル全体がシフトするものであり，局所的な吸収スペクトルシフトではない。したがって，この記録方法を用いることにより，２つ以上の互いに異なる記録波長で情報の記録を可能とし，かつ２つ以上の異なる再生波長である波長で記録した情報を再生することができる。
【００４５】
図１は，上記吸収スペクトルのシフトを説明するための説明図である。図１において，吸収スペクトルのピーク波長に対して長波長側では，色素の凝集状態を変化させることによって吸収スペクトルのシフトを生じさせる。一方，吸収スペクトルのピーク波長に対して短波長側では，色素の凝集状態を変化させることによって，吸収スペクトルを増加させる。そして，吸収スペクトルの変化が生じた長波長及び短波長の両者の波長のレーザ光を照射した場合に，そのレーザ光の反射率を低下させることができるようにすることによって情報を記録することができる。
【００４６】
なお，図１においては，再生波長が色素のピーク波長に対して長波長側と短波長側に存在すると仮定したが，２つの再生波長が長波長側にあっても，短波長側にあっても良い。
【００４７】
したがって，この情報記録方法により，２つの互いに異なる波長の光で情報を記録することができ，かつこの記録により，再生波長のレーザ光に対する反射率を情報が記録されていない状態に対して低下させることができる。よって，ある波長で記録した情報を，２つ以上の異なる波長のレーザ光で再生することが可能となる。この再生方法は，情報の記録により反射率が低下するというＣＤ系メディアと同一の方法を用いるものであるであるため，他のＣＤ系メディアとの互換性を持たせることができる。
【００４８】
具体的に，本発明に係る光情報記録媒体では，７６０〜８３０ｎｍ及び６２０〜６５０ｎｍの波長域から選択された波長のレーザ光で情報を記録することにより，７６０〜８３０ｎｍ及び６２０〜６５０ｎｍの波長域近傍の吸収スペクトルを変化させる。また，情報は，情報が記録されていない状態の反射率に対して，７６０〜８３０ｎｍ及び６２０〜６５０ｎｍの波長域から選択された波長のレーザ光に対する反射率が低下することを利用して記録される。
【００４９】
これにより，７６０〜８３０ｎｍの波長域から選択された波長のレーザ光で記録された情報を，７６０〜８３０ｎｍの波長域から選択された波長のレーザ光及び６２０〜６５０ｎｍの波長域から選択された波長のレーザ光の両者を用いても，未記録状態の反射率に対する反射率の低下として情報を再生することができる。一方，６２０〜６５０ｎｍの波長域から選択された波長のレーザ光で記録された情報も，７６０〜８３０ｎｍの波長域から選択された波長のレーザ光及び６２０〜６５０ｎｍの波長域から選択された波長のレーザ光の両者を用いても，未記録状態の反射率に対する反射率の低下として情報を再生することができる。
【００５０】
このように，ある波長のレーザ光で，色素の凝集状態を変化させて複数の波長域の吸収スペクトルを変化させ，かつその変化により複数の波長域のレーザ光に対する反射率を低下させて情報を記録することができることが本発明の光情報記録媒体の情報記録方法の特徴である。
【００５１】
更に，本発明の光情報記録媒体の情報再生方法では，前述した光情報記録媒体において，吸収スペクトルの変化が生じ，反射率を低下させる複数の波長域の光を照射することにより，光情報記録媒体に記録された情報を再生することができる。
【００５２】
例えば，前述した図１に示すように，吸収スペクトルの変化が生じた長波長側及び短波長側の波長域から選択された波長のレーザ光を照射することにより，図１に示すような２つの異なる波長域に記録された情報を，反射率の低下を検出することによって再生することができる。なお，図１において，情報の２つの再生波長が，吸収スペクトルのピーク波長に対して長波長側及び短波長側の波長域にあるとして情報の再生を説明したが，２つの再生波長が吸収スペクトルのピーク波長に対して，長波長側又は短波長側の一方に存在する場合であっても情報を再生することができる。
【００５３】
前述したように，本発明の光情報記録媒体においては，７６０〜８３０ｎｍ及び６２０〜６５０ｎｍの波長域から選択された波長のレーザ光で情報を記録することができ，７６０〜８３０ｎｍ及び６２０〜６５０ｎｍの波長域近傍の吸収スペクトルを変化させる。情報は，未記録状態の反射率に対して，７６０〜８３０ｎｍ及び６２０〜６５０ｎｍの波長域近傍の反射率を低下させることによって記録される。
【００５４】
これにより，７６０〜８３０ｎｍの波長域から選択された波長のレーザ光で記録された情報を，７６０〜８３０ｎｍの波長域から選択された波長のレーザ光及び６２０〜６５０ｎｍの波長域から選択された波長のレーザ光の両者によって，未記録状態の反射率に対する反射率の低下として情報を再生することができる。一方，６２０〜６５０ｎｍの波長域から選択された波長のレーザ光で記録された情報も，７６０〜８３０ｎｍの波長域から選択された波長のレーザ光及び６２０〜６５０ｎｍの波長域から選択された波長のレーザ光の両者によって，未記録状態の反射率に対する反射率の低下として情報を再生することができる。
【００５５】
このように，吸収スペクトルの変化を用いて反射率の低下として記録された情報を，複数の波長域から選択された波長のレーザ光を照射することによって反射率の低下を検出し，情報を再生することが本発明の光情報記録媒体の情報再生方法の特徴である。
【００５６】
【発明の実施の形態】
以下，本発明に係る光情報記録媒体，光情報記録媒体の記録方法及び再生方法の実施の形態を図面を参照しつつ詳細に説明する。
【００５７】
本発明の実施の形態においては，有機材料で追記性を持った記録材料を説明すると共に，ＣＤ系メディア及びＤＶＤ系メディアと互換性のある追記型光情報記録媒体について説明する。すなわち，現状において市場に出回っているＣＤ−Ｒや今後登場してくるＤＶＤ−Ｒ系のような１回だけ書込可能な高感度の追記型光情報記録媒体について説明する。
【００５８】
（記録層に用いる色素）
現在ＣＤ系メディアやＰＤ，ＭＤ，ＭＯ等の光ディスクは，記録容量が最高で６５０ＭＢ程度である。また，追記型のものについては有機材料が，書換型のものについては無機材料が用いられれている。
【００５９】
相変化材料等の無機材料の実績から，前記容量においては書換型のものの材料として有機材料が用いられるということは考えられない。しかしながら，今後ＤＶＤ系メディアが普及していくにつれ，追記型はもちろんであるが，書換型においても有機材料が適用される可能性がある。
【００６０】
なぜなら，無機材料は感度が悪く，有機材料に対して１〜２桁熱伝導率及び熱拡散係数が大きいからである。また，ＲＯＭとの互換性を考えると，追記型及び書換型の両者に対し，ＲＯＭのような高反射率が要求される場合があり，無機材料では，このような高反射率を達成することが困難であるからである。
【００６１】
現状でも，ＤＶＤ−ＲＯＭが容量４．７ＧＢ以上であるのに対し，相変化材料を用いたＤＶＤ−ＲＡＭは，マークエッジ記録やランド・グルーブ記録を用いたとしても容量が２．９ＧＢ程度である。そこで，本発明の発明者は，高感度化及び高転送レート化が可能な材料として，有機材料を用いることを検討した。
【００６２】
現在，フタロシアニン，ナフタロシアニン化合物は，光情報記録媒体の材料として最も適した材料の１つである。ところが，ＣＤ−Ｒ，即ちユーザが１回だけ情報を書き込めるタイプのメディアにおいて，フタロシアニン，ナフタロシアニン化合物は，単に情報記録時のレーザ光吸収用として使用されるのみである。そして，情報は，レーザ光吸収によるフタロシアニン，ナフタロシアニン化合物の分解，あるいはフタロシアニン，ナフタロシアニン化合物のレーザ光吸収による基板の変形を用いて記録される。このレーザ光吸収によって基板を変形させ，情報の記録を行った様子は，前述した図２２に示した通りである。この図２２に示す記録メカニズムでは，高速再生時のジッタが大きくなり，高転送レート化を図ることができないという問題がある。
【００６３】
特に，ＤＶＤ系メディアにおいては，再生時の高速化と共に記録時の高速化も要求される。そのためには，記録膜の感度が非常に重要である。しかしながら，現状のＣＤ−Ｒのような熱分解，熱変形によって情報の記録を行う場合には，高出力のレーザが必要となり，記録レスポンスの点から好ましくない。
【００６４】
また，ＤＶＤ系メディアにおいては，ＤＶＤ−ＲＯＭが４．７ＧＢ以上の容量を有することから，追記型及び書換型のＤＶＤについても同等の容量を有することが好ましい。しかしながら，現在ＲＡＭとして脚光を浴びているものは，相変化型の材料を用いたものであり，マークエッジ記録やランド・グルーブ方式の高密度化手法を用いても容量が２．９ＧＢ程度にとどまっている。
【００６５】
この理由は，無機材料が基本的に感度が悪いこと，有機材料に比べて１〜２桁熱伝導率及び熱拡散係数が大きいことによる。したがって，高速で高感度に記録でき，低ジッタで情報が再生できる記録材料が非常に望まれているのである。
【００６６】
本発明においては，従来のように単なる吸収材としてフタロシアニン，ナフタロシアニン化合物を使用するのではなく，フタロシアニン，ナフタロシアニン化合物自体の物性変化を直接的に利用することにより，基板変形，色素の物理的変化等による表面形状の変化を伴わない光情報記録媒体用材料を特定し，光情報記録媒体，光情報記録媒体の情報記録方法及び情報再生方法を提供する。
【００６７】
フタロシアニン，ナフタロシアニン化合物等の色素化合物による吸収スペクトル変化は，例えば結晶状態，凝集状態，会合状態，構造・電子的状態等の変化により生ずる。
【００６８】
凝集状態の変化を利用する吸収スペクトルの変化は，色素分子と色素分子間の相互作用が変化するものである。例えば，色素分子が他の色素分子と相互作用しない単独に存在する状態，即ち分散された状態に対し，色素分子が凝集すると，吸収スペクトルが短波長又は長波長へシフトする。例えば，図２に示すように，太線の吸収スペクトルから細線の吸収スペクトルにシフトする。
【００６９】
また，前述した図１に示すように，ある色素の凝集状態に対し，色素−色素間の相互作用が変化し，図２に示す凝集状態とは異なる色素凝集状態を示すことで，吸収スペクトルが短波長又は長波長へシフトを起こす。
【００７０】
２つ以上の色素分子が分子オーダーの距離又はそれ以下に近づいた場合，色素のいわゆるＪ−会合，Ｈ−会合等の会合現象が見られる。これは凝集状態の変化に当たるものである。一般的に，結晶状態の変化，相変化等は，膜の表面状態が激しく，光メモリには適していないため，色素の凝集状態を外部エネルギーにより変化させることのできる色素を探索する必要がある。
【００７１】
本発明は，
（ａ）記録により色素分子の吸収スペクトルを変化させることができなくなるような，色素分子の基本骨格同士の分子間力や静電力，双極子相互作用等の力による会合，凝集を防ぎ，
（ｂ）記録により色素分子の吸収スペクトルをコントロールできるような程度に初期的に会合，凝集しており，
（ｃ）また，逆に記録によっても色素分子が互いに相互作用を生じないことを防ぎ，色素分子の吸収スペクトルを記録によりコントロールできるような程度に初期から会合，凝集させられる色素分子として，色素分子に置換基を設けた色素，好ましくは中心金属に置換基を有する色素，更に好ましくは中心金属にアルキル置換基を有する色素を用い，この置換基の凝集力や置換基の空間的広がりにより会合，凝集させ，この効果により色素基本骨格のπ共役系の相互作用を生じ，色素のある状態に対して色素分子の吸収スペクトルを変化させることに特徴がある。
【００７２】
このように本発明に用いる色素は，色素分子に置換基，好ましくは中心金属に置換基，更に好ましくは中心金属にアルキル置換基を有するものである。
【００７３】
色素分子に置換基ない場合（中心金属以外の部分に置換された置換基も含めて）や，置換基が小さい場合等は，色素分子間の距離が狭く，色素分子同士の相互作用力が大きい。このため，外部エネルギーによる記録処理を施しても相互作用力を変化させることができず，吸収スペクトルを変化させることができない。したがって，吸収スペクトル可動性がないため，記録層の形状変化を伴わない追記もできない。
【００７４】
他方，置換基が３次元的に非常に大きい場合等は，色素基本骨格同士の相互作用が弱められ，置換基の分子間力相互作用により，色素分子が会合，凝集状態を形成するが，色素分子の基本骨格の距離が大きくなり，色素分子基本骨格のπ共役系間の相互作用がほとんどなくなる可能性もある。そのためには，記録による色素分子間相互作用の変化が少なくなり，吸収スペクトルシフトが期待できない（ある１つの安定色素凝集状態ともう１つの安定色素凝集状態の吸収スペクトル差が小さくなる。）。したがって，記録により色素分子間の相互作用力を変えることを可能にするためには（吸収スペクトルの可動性），十分な吸収スペクトルシフトを起こすような距離圏内に色素分子同士を引き込み，しかも吸収スペクトル可動性を持たせるために，色素分子同士を近づけすぎないようにすることが重要である。
【００７５】
また，本発明では，吸収スペクトル可動性，可逆性の発現，安定性の向上，成膜性や膜均一性の改善のため，色素に高分子化合物を添加しても良い。
【００７６】
本発明において好ましい色素構造は，色素分子同士を近づけすぎないようにするため，色素分子の中心金属に置換基を設け，かつ色素分子同士を十分な吸収スペクトルシフトを起こすような距離圏内引き込むようにする作用を置換基の凝集力（分子間力）及び置換基の空間的広がりに持たせるものである。
【００７７】
フタロシアニン，ナフタロシアニン化合物を置換基のつく場所で大きく分類すると，
１）α位に置換基を有するタイプ
２）β位に置換基を有するタイプ
３）中心金属に置換基を有するタイプ
にわけることができる。
【００７８】
これらのうち，α位に置換基を有するタイプ及びβ位に置換基を有するタイプのフタロシアニン，ナフタロシアニン化合物は，異性体の存在や置換基の回転・振動によるエネルギー準位の存在によって吸収スペクトルが広がり易い。したがって，会合等の凝集状態変化による吸収スペクトル変化が生じても，その変化が非常に大きくなければ記録コントラストは低い（図３）。
【００７９】
他方，中心金属に置換基を有するタイプ，いわゆる軸配位子のフタロシアニン，ナフタロシアニン化合物は，一般的に軸配位子の影響がフタロシアニン，ナフタロシアニン化合物の基本骨格に与える影響が少ないため，軸配位子の回転・振動によるエネルギー状態間にほとんど差がない。また，α位やβ位に置換基を導入しなければ，異性体も存在しないため，吸収スペクトルの広がりがなく，溶液状態のような鋭いピークを持つ吸収スペクトルを示す。
【００８０】
したがって，このような軸配位子型の色素は，会合，凝集状態の変化による色素分子と色素分子間の相互作用変化によってわずかに吸収スペクトルが変化しても，もとの（ある安定状態）吸収スペクトルが非常にシャープであるため記録コントラストが高くなる（図１及び図２参照）。
【００８１】
更に，ＣＤ系，ＤＶＤ系メディアと互換性を持たせる構造とした場合，即ち記録層の上に金属反射層を設けたとき，α位に置換基を有するタイプ及びβ位に置換基を有するタイプのフタロシアニン，ナフタロシアニン化合物は吸収スペクトルがブロードで，もともと追記変化の２つの安定状態を含んだ吸収スペクトル形状を示すこと，本来メイン構造の色素には存在しないはずの波長領域にも，異性体の存在や置換基の回転・振動によるエネルギー準位の存在により吸収が存在すること等により，初期から記録・再生波長に比較的大きな吸収がある場合が多くなり，初期（未記録，消去時）の反射率が低下するおそれがある。
【００８２】
つまり未記録・消去時の反射率を高くするような記録・再生波長を選択し（その波長ではほとんど吸収がない），その波長に大きな吸収を持たせるようにする程，吸収スペクトルを動かすことができない可能性がある。
【００８３】
他方，中心金属に置換基を有するタイプ，即ちいわゆる軸配位子型のフタロシアニン，ナフタロシアニン化合物は，逆に未記録・消去時の反射率を高くするような記録・再生波長を選択しても，その波長に大きな吸収を持たせるようになるくらいに吸収スペクトルを動かすことが可能である（少しの吸収スペクトル変化で良い）。
【００８４】
この軸配位子は，無置換状態のように，色素分子間の相互作用が非常に大きい状態から色素分子間の距離を広げる働きを担い，吸収スペクトル可動性を持たせることが可能になると同時に，色素間の相互作用を失わせない作用を担う。つまり，軸配位子を適当に選択することによって，軸配位子の凝集力及び軸配位子の空間的広がりで色素分子間の距離，凝集する角度等の凝集状態をコントロールできるため，記録コントラストが高く，良好な追記性を有する記録材料の提供が可能となる。
【００８５】
このような理由により，中心金属に置換基を有するタイプ，即ちいわゆる軸配位子型のフタロシアニン，ナフタロシアニン等の化合物を有機光情報記録媒体用材料として選択したことが本発明の重要な点である。
【００８６】
さて，大きな吸収スペクトル変化を起こすためには，まず色素分子同士，つまり色素基本骨格のπ共役系同士を置換基同士の分子間力等の相互作用で吸収スペクトルの変化が十分大きくなるような距離に引き込むことが必要である。
【００８７】
この場合，色素分子同士が接近しすぎても吸収スペクトル可動性を失う可能性があるため好ましくない。しかし，中心金属に置換基を有するタイプ，即ちいわゆる軸配位子型のフタロシアニン，ナフタロシアニン等の化合物は，その軸配位子によって色素分子同士が接近できる距離，角度等の凝集状態をコントロールすることができるので都合が良い。
【００８８】
このように本発明の発明者は，特定軸配位子の長さ及び軸配位子の空間的広がりをコントロールすることにより，追記性を制御できることを見い出した。
【００８９】
ところで，色素−色素間の相互作用による吸収スペクトルは，単分子状態のハミルトニアンに双極子−双極子相互作用の項を取り込むことで近似できる。すなわち，双極子−双極子相互作用は次式で表される。
【数１】

なお，図４は，フタロシニアン，ナフタロシニアン等の化合物の主骨格の位置と吸収スペクトルの変化量を説明するための説明図である。
【００９０】
いま，双極子−双極子相互作用の項のみを考え，この相互作用によるエネルギー変化を調べると，図５のようになる。この図５から明らかなように，フタロシアニン，ナフタロシアニン等の化合物における主骨格がθ方向又はφ方向に，あるいはθ方向及びφ方向の混合で，どのような位置をとるかによって吸収スペクトルの変化量も変わることがわかる。
【００９１】
双極子−双極子相互作用の式からわかるように，この相互作用によるエネルギー変化を大きくするためには，図４において，双極子モーメントの大きさμ_Ａ ，μ_Ｂ を大きくすること，距離ｒを小さくすること，あるいはφ，θを最適化することが必要である。
【００９２】
双極子モーメントの大きさμ_Ａ ，μ_Ｂ を大きくすることは，フタロシアニン，ナフタロシアニン等の化合物における主骨格環を変えることに対応するため，容易に分子設計できない。
【００９３】
また，前述したように，距離ｒを極端に小さくすることは吸収スペクトル可動性を失うため，好ましくない。
【００９４】
本発明では，双極子−双極子相互作用力の変化，即ち色素基本骨格π共役系間の相互作用力変化によって吸収スペクトルシフトを大きくすることを，吸収スペクトル可動性を失わない範囲で色素基本骨格間距離ｒ，θ方向，φ方向の配置をコントロールすることにより行う。すなわち，本発明の発明者は，中心金属の置換基，即ち軸配位子を選択することで上記コントロールを行うことができることを見い出した。
【００９５】
更に，本発明の発明者は，軸配位子を選択することにより，情報の記録によってある程度規則性をもって色素を凝集させることができることを見い出した。本発明での情報の記録は，色素のある安定凝集状態に対し，別の安定な凝集状態へと変化させることによって行われる。
【００９６】
軸配位子を変えることで軸配位子の傾き，立体障害性，かさ高さ，たわみ易さ等をコントロールでき，従って色素分子同士の相互作用配置，凝集状態の規則性を変えることができる。
【００９７】
このような配位子としてはアルキル基が好ましい。これは，アルキル基が適当な凝集力を有し，アルキル基を大きくしても色素基本骨格π共役系間の相互作用を持たせることができるためである。
【００９８】
例えば，以下の（１）式及び（２）式で示される化合物Ｒ１，Ｒ２，Ｒ３におけるアルキル基は，前述の双極子−双極子相互作用によるエネルギー変化を見てもわかるように，ある１つの色素凝集状態からの吸収スペクトル変化量を大きくするために，他方の色素凝集状態を規則性を持って凝集させることが好ましい。このような状態にするためには，例えば軸配位子が比較的立った状態になるアルキル基が選択され，色素分子同士がいわゆるＨ会合した状態をとるような又は軸配位子が極端に寝た状態になるアルキル基が選択され，色素分子同士がいわゆるＪ会合した状態をとるような状態が好ましく，このような状態をとるための最適組合せが存在する。
【００９９】
【化３】

【０１００】
【化４】

【０１０１】
ただし，Ｘ^１ 〜Ｘ^４ は，それぞれ独立に水素原子，ハロゲン原子，置換基を有しても良いアルキル基，置換基を有しても良いアリール基，置換基を有しても良いアルコキシ基，置換基を有しても良いアリールオキシ基，置換基を有しても良いアルキルチオ基，置換基を有しても良いアリールチオ基，ニトロ基，シアノ基，スルホン酸基，スルホン酸アミド基，スルホン酸エステル基を示す。ｋ，ｌ，ｍ，ｎは，置換基Ｘ^１ 〜Ｘ^４ の置換数で０〜４の整数を示す。
【０１０２】
２つの色素凝集状態として，色素の分散状態に近い状態と色素の凝集状態を安定的に形成しやすい色素構造としては，例えば（１）式及び（２）式で示される化合物において，Ｒ１，Ｒ２，Ｒ３がアルキル基であり，Ｒ１，Ｒ２，Ｒ３はアルキル基の種類が異なっても良く，好ましい１例としては，Ｒ３はＲ１とＲ２のうち炭素数の大きいアルキル基よりも炭素数で３つ以上の差を有するアルキル基，又は（１）式及び（２）式で示される化合物において，Ｒ１，Ｒ２，Ｒ３はアルキル基であって，Ｒ１，Ｒ２，Ｒ３はアルキル基の種類が異なっても良く，Ｒ１，Ｒ２は炭素数３以下のアルキル基であり，Ｒ３はＲ１とＲ２のうち炭素数の大きいアルキル基よりも炭素数３つ以上の差を有するアルキル基が吸収スペクトル変化を大きくできる最適組み合わせである。
【０１０３】
軸配位子に適したアルキル基としては，メチル基，エチル基，ｎ−プロピル基，ｎ−ブチル基，イソブチル基，ｎ−ペンチル基，ネオペンチル基，イソアミル基，２−メチルブチル基，ｎ−ヘキシル基，２−メチルペンチル基，３−メチルペンチル基，４−メチルペンチル基，２−エチルブチル基，ｎ−ヘプチル基，２ーメチルヘキシル基，３−メチルヘキシル基，４−メチルヘキシル基，５−メチルヘキシル基，２−エチルペンチル基，３−エチルペンチル基，ｎ−オクチル基，２−メチルヘプチル基，３−メチルヘプチル基，４−メチルヘプチル基，５−メチルヘプチル基，２−エチルヘキシル基，３−エチルヘキシル基，ｎ−ノニル基，ｎ−デシル基，ｎ−ドデシル基等の一級アルキル基，イソプロピル基，ｓｅｃ−ブチル基，１−エチルプロピル基，１−メチルブチル基，１，２−ジメチルプロピル基，１−メチルヘプチル基，１−エチルブチル基，１，３−ジメチルブチル基，１，２−ジメチルブチル基，１−エチル−２−メチルプロピル基，１−メチルヘキシル基，１−エチルヘプチル基，１−プロピルブチル基，１−イソプロピル−２−メチルプロピル基，１−エチル−２−メチルブチル基，１−プロピル−２−メチルプロピル基，１−メチルヘプチル基，１−エチルヘキシル基，１−プロピルペンチル基，１−イソプロピルペンチル基，１−イソプロピル−２−メチルブチル基，１−イソプロピル−３−メチルブチル基，１−メチルオクチル基，１−エチルプロピル基，１−プロピルヘキシル基，１−イソブチル−３−メチルブチル基等の二級アルキル基，ｔｅｒｔ−ブチル基，ｔｅｒｔ−ヘキシル基，ｔｅｒｔ−アミル基，ｔｅｒｔ−オクチル基等の三級アルキル基，シクロヘキシル基，４−メチルシクロヘキシル基，４−エチルシクロヘキシル基，４−ｔｅｒｔ−ブチルシクロヘキシル基，４−（２−エチルヘキシル）シクロヘキシル基，ボルニル基，イソボニル基，アダマンタン基等のシクロアルキル基等が挙げられる。
【０１０４】
また，（１）式及び（２）式中のＸ^１ 〜Ｘ^４ は，それぞれ独立に水素原子，ハロゲン原子，置換基を有しても良いアルキル基，置換基を有しても良いアリール基，置換基を有しても良いアルコキシ基，置換基を有しても良いアリールオキシ基，置換基を有しても良いアルキルチオ基，置換基を有しても良いアリールチオ基，ニトロ基，シアノ基，スルホン酸基，スルホン酸アミド基，スルホン酸エステル基を示す。ｋ，ｌ，ｍ，ｎは，置換基Ｘ^１ 〜Ｘ^４ の置換数で０〜４の整数を示す。（１）式及び（２）式中のＸ^１ 〜Ｘ^４ は，好ましくは置換基があまり立体的に大きくなく，置換基の数としても少ないものが良い。これは置換基として立体的に大きいもの，また，置換基を数多く導入することは，軸配位子型色素吸収スペクトルの特徴を失わせるものであるからである。
【０１０５】
具体的に説明すると，（１）式及び（２）式で示される化合物において，Ｒ１，Ｒ２，Ｒ３が同一で大きなアルキル基である場合には，空間的に密で色素基本骨格π共役系同士があまり近づけなく（図４に示すｒが大きくなる），色素基本骨格π共役系の相互作用が低下するため，吸収スペクトルシフト量が小さい。
【０１０６】
また，アルキル基３つが全て大きなアルキル基であるとすると，そのアルキル基部分が結晶化し易くなり，光情報記録媒体として使用することができない。
【０１０７】
そこで，（１）式及び（２）式に示される化合物において，Ｒ１，Ｒ２，Ｒ３のうちの１つのアルキル基を長くし，他の２つを短くすることで，上記問題を改善することができる。これによって，大きな吸収スペクトル変化を生じる記録材料を得ることができる。
【０１０８】
しかしながら，これらの色素吸収スペクトル変化は，初期的にある程度ランダムな状態から記録によって色素分子間の相互作用が強まるように凝集する変化であり，記録した状態が色素が規則性をもって凝集した状態ではない。したがって，その吸収スペクトル変化が図６に示すような相似的移動で，吸収スペクトルのピーク波長に対して短波長側と長波長側では，記録による反射率の極性が異なる（逆になる）。そのため，ある１つの記録波長で記録された情報が，２以上の異なる波長で，記録情報が反射率の低下として再生することができない可能性がある。また，現実的には（１）式に示されたフタロシアニン化合物の場合，７８０ｎｍ付近と６３０ｎｍ付近の波長域はそれぞれ，図７において吸収スペクトルのピーク波長に対して長波長側のすそと短波長側のすそ付近に対応する（もちろんそれぞれ吸収スペクトルは異なる）。そのため，７６０ｎｍ〜８３０ｎｍの波長でも，６２０〜６５０ｎｍの波長でも，両方で記録された情報を反射率の低下として再生することは不可能である。これを解決するためには，単に情報の記録によって未記録状態に対してある程度凝集性を増加させたり，逆に分散化させるだけでは不可能で，色素分子の凝集性に秩序性を持たせる必要がある。
【０１０９】
本発明の発明者は，以下の（３）式に示されるフタロシアニン化合物が，類似する他の色素とは異なる特性を示すことを見い出した。
【０１１０】
【化５】

【０１１１】
すなわち，（３）式に示されるフタロシアニン化合物によれば，未記録状態からある程度色素が規則性をもって凝集し，かつ記録によって更に色素の規則性が高まり，大きな凝集状態変化をもたらす。
【０１１２】
成膜性や膜均一性，記録，再生特性を改善するため，更に上記色素に高分子を添加しても良い。
【０１１３】
具体的に好ましい例としては，以下の（４）式で示されるポリメタクリル酸エステル，（５）式で示されるポリスチレン置換体を挙げることができる。ポリメタクリル酸エステルにおいて，Ｒが，分岐を有しても良い炭素数３以上のアルキル基が好ましい。ポリスチレン置換体においては，置換基がＺ１〜Ｚ６のうち少なくとも１カ所以上に炭素数３以上の分岐を有しても良いアルキル基が置換されていることが好ましい。ただし，そのうちの置換基の１つの位置がＺ６の場合は，炭素数１以上の分岐を有しても良いアルキル基が置換されていることが好ましく，置換基は複数導入されていても良い。
【０１１４】
【化６】

【０１１５】
【化７】

【０１１６】
これらの高分子の規定は，側鎖へのアルキル基導入，また，側鎖に立体障害をもたらすかさ高い置換基を導入することにより，高分子間の相互作用を低下させるため，さらには側鎖のアルキル基と色素分子の置換基，具体的には中心金属に置換されたアルキル基部分との分子間力，即ち相互作用を高めるために必要である。
【０１１７】
また，他の好ましい高分子化合物として，（６）式に示される高分子化合物を挙げることができる。
【０１１８】
【化８】

【０１１９】
（６）式中，Ｒ１１，Ｒ１２は，水素又は置換基を有しても良いアルキル基を示す。これらは同一であっても良いが，両方同時に水素を有することはなく，少なくとも一方は置換基を有しても良いアルキル基である。（６）式において，ＸはＳ，Ｏ，Ｓｅ又はＮＲ^１３であり，Ｒ^１３は水素，アルキル基又はアリール基を示す。これらのうち，好ましくはＸが硫黄原子であるポリチオフェン誘導体で，更に好ましくは，Ｒ１１，Ｒ１２のうち，１つが水素原子で，他方がアルキル基であるポリ（３−アルキルチオフェン）である。また，ポリ（３−アルキルチオフェン）のうちでも，有機溶媒への溶解性，高分子間の相互作用力，色素分子との相互作用力等の関係からｎ＝６以上のアルキル基が好ましい。
【０１２０】
（記録層）
記録層の形成に当たっては，光エネルギーの効率，波長整合性，色素の分子集合状態，分散状態，結晶状態の変化促進のため，他の色素を添加しても良い。そのような色素としては，例えばポリメチン色素，ナフタロシアニン系，フタロシアニン系，スクアリリウム系，コロコニウム系，ピリリウム系，ナフトキノン系，アントラキノン（インダンスレン）系，キサンテン系，トリフェニルメタン系，アズレン系，テトラヒドロコリン系，フェナンスレン系，トリフェチアジン系染料及び金属錯体化合物等が挙げられる。上記の染料を単独で用いても良いし，また２種以上の組合せにしても良い。また，上記染料中に金属，金属化合物，例えばＩｎ，Ｔｅ，Ｂｉ，Ａｌ，Ｂｅ，ＴｅＯ_２ ，ＳｎＯ，Ａｓ，Ｃｄ等を分散混合，あるいは積層の形態で用いることもできる。更に，上記染料中に高分子材料，例えばアイオノマー樹脂，ポリアミド系樹脂，ビニル系樹脂，天然高分子，シリコーン，液状ゴム等の種々の材料，もしくはシランカップリング剤等を分散混合して用いても良いし，あるいは特性改良の目的で，安定剤（例えば遷移金属錯体），分散剤，難燃剤，滑剤，帯電防止剤，界面活性剤，可塑剤等と一緒に用いることができる。
【０１２１】
記録層の形成は，蒸着，スパッタリング，ＣＶＤ又は溶剤塗布等の通常の方法によって行うことができる。塗布法を用いる場合には，上記染料等を有機溶媒に溶解させて，スプレー，ローラコーティング，ディッピング及びスピンコーティング等の慣用のコーティング法によって行われる。
【０１２２】
上記有機溶媒としては，一般にメタノール，エタノール，イソプロパノール等のアルコール類，アセトン，メチルエチルケトン，シクロヘキサン等のケトン類，Ｎ，Ｎ−ジメチルアセトアミド，Ｎ−Ｎジメチルホルムアミド等のアミド類，ジメチルスホキシド等のスルホキシド類，テトラヒドロフラン，ジオキサン，ジエチルエーテル，エチレングリコールモノメチルエーテル等のエーテル類，酢酸メチル，酢酸エチル等のエステル類，クロロホルム，塩化メチレン，ジクロロエタン，四塩化炭素，トリクロロエタン等の脂肪族ハロゲン化炭素類，あるいはベンゼン，キシレン，モノクロロベンゼン，ジクロロベンゼン等の芳香族類，メトキシエタノール，エトキシエタノール等のセルソルブ類，ヘキサン，ペンタン，シクロヘキサン，メチルシクロヘキサン等の炭化水素類等を用いることができる。
【０１２３】
なお，記録層の膜厚は，１００オングストローム〜１０μｍ，好ましくは２００〜２０００オングストロームが適当である。
【０１２４】
（基板）
基板は，基板側より記録・再生を行う場合にのみ，使用されるレーザ光に対して透明でなければならず，記録層側から記録・再生を行う場合には，透明である必要はない。
【０１２５】
基板材料としては，例えば，ポリエステル，アクリル樹脂，ポリアミド，ポリカーボネート樹脂，ポリオレフィン樹脂，フェノール樹脂，エポキシ樹脂，ポリイミド等のプラスチック，あるいはガラス，セラミック，金属等を用いることができる。
【０１２６】
なお，基板の表面にトラッキング用の案内溝や案内ピット，更にアドレス信号等のプレフォーマットが形成されていても良い。
【０１２７】
（下引き層）
下引き層は，
（ａ）接着性の向上，
（ｂ）水又はガス等のバリアー，
（ｃ）記録層の保存安定性の向上，
（ｄ）反射率の向上，
（ｅ）溶剤からの基板の保護，
（ｆ）案内溝・案内ピット・プレフォーマット等の形成
等を目的として使用される。
【０１２８】
（ａ）の目的に対しては，高分子材料，例えばアイオノマー樹脂，ポリアミド樹脂，ビニル系樹脂，天然樹脂，天然高分子，シリコーン，液状ゴム等の種々の高分子物質，及びシランカップリング剤等を用いることができる。
【０１２９】
（ｂ）及び（ｃ）の目的に対しては，上記高分子材料以外に，無機化合物，例えばＳｉＯ_２ ，ＭｇＦ_２ ，ＳｉＯ，ＴｉＯ_２ ，ＺｎＯ，ＴｉＮ，ＳｉＮ等の金属又は半金属，例えばＺｎ，Ｃｕ，Ｎｉ，Ｃｒ，Ｇｅ，Ｓｅ，Ａｕ，Ａｇ，Ａｌ等を用いることができる。
【０１３０】
（ｄ）の目的に対しては，例えばＡｌ，Ａｇ等や，金属光沢を有する有機薄膜，例えばメチン染料，キサンテン系染料等を用いることができる。
【０１３１】
（ｅ）及び（ｆ）の目的に対しては，紫外線硬化樹脂，熱硬化樹脂，熱可塑性樹脂等を用いることができる。
【０１３２】
なお，下引き層の膜厚は，０．０１〜３０μｍ，好ましくは０．０５〜１０μｍが適当である。
【０１３３】
（保護層・基板表面ハードコート層）
保護層又は基板表面ハードコート層は，
（ａ）記録層（反射吸収層）の傷，ホコリ，汚れ等からの保護，
（ｂ）記録層（反射吸収層）の保存安定性の向上，
（ｃ）反射率の向上
等を目的として使用される。
【０１３４】
上記の目的に対しては，前記下引き層の説明の際に示した材料を用いることができる。また，無機材料として，ＳｉＯ，ＳｉＯ_２ 等も用いることができ，有機材料として，ポリメチルアクリレート，ポリカーボネート，エポキシ樹脂，ポリスチレン，ポリエステル樹脂，ビニル樹脂，セルロース，脂肪族炭化水素樹脂，芳香族炭化水素樹脂，天然ゴム，スチレン−ブタジエン樹脂，クロロプレンゴム，ワックス，アルキッド樹脂，乾性油，ロジン等の熱軟化性，熱溶融樹脂も用いることができる。
【０１３５】
上記材料のうち，保護層又は基板表面ハードコート層に最も好ましい物質は，生産性に優れた紫外線硬化樹脂である。保護層又は基板表面ハードコート層の膜厚は，０．０１〜３０μｍ，好ましくは０．０５〜１０μｍが適当である。
【０１３６】
本発明においては，下引き層，保護層及び基板表面ハードコート層には，記録層の場合と同様に，安定剤，分散剤，難燃剤，滑剤，帯電防止剤，界面活性剤，可塑剤等を含有させることができる。
【０１３７】
（金属反射層）
反射層には，単体で高反射率が得られ，腐食されにくい金属，半金属等を用いることができる。材料の例としては，Ａｕ，Ａｇ，Ｃｕ，Ｃｒ，Ｎｉ，Ａｌ等を挙げることができ，好ましくはＡｕ，Ａｌが良い。これらの金属，半金属は，単独で使用しても良く，２種以上の合金としても良い。
【０１３８】
反射層の膜形成方法としては，蒸着，スパッタリング等が挙げられ，膜厚としては，５０〜３０００オングストローム，好ましくは１００〜１０００オングストロームである。
【０１３９】
次に，本発明の光情報記録媒体の実施例を説明する。
［実施例１］
【０１４０】
以下の（７）式で示されるフタロシアニン化合物において，ｎが７及び１１である２つの化合物を合成した。このフタロシアニン化合物をクロロホルムに溶解させ，スピンコーティング法によりガラス基板上に薄膜を形成した。
【０１４１】
【化９】

【０１４２】
この２つの化合物の分光特性を測定した結果が図８及び図９であり，図８はｎが７の場合，図９はｎが１１の場合を示している。図８及び図９から明らかなように，この色素が初期的（未記録状態）に，複数の安定した凝集状態を形成することがわかる。
【０１４３】
また，２つの化合物のクロロホルム溶液の吸収スペクトルは，それぞれ図１０及び図１１に示す通りであって，両者とも溶液状態では，ほとんど色素間相互作用がなく，分子が単一分散状態となっていると考えられる。このことから，（７）式の色素が，固体となるときに特異な凝集状態を生じていることがわかる。
【０１４４】
更に，ｎ＝７及び１１の色素について，初期，１００℃，１５０℃，１８０℃，２００℃に加熱したときの吸収スペクトルを測定した。その結果を図１２及び図１３に示す。なお，図１２はｎ＝７，図１３はｎ＝１１の場合の結果を示している。図１２及び図１３に示すように，加熱により吸収スペクトルの変化が生じており，加熱により色素の凝集状態を変化させることができることがわかる。
【０１４５】
この色素の初期，１００℃，１５０℃，１８０℃，２００℃の加熱による膜状態を高分解能の顕微鏡で観察した結果，表面形状には全く変化はなく，均一であった。すなわち，記録層の表面形状の変化による乱反射で吸収スペクトルの変化が生じたのではなく，純粋な凝集状態の変化により生じたものであることがわかった。
【０１４６】
［比較例］
前述した実施例１に対する比較例として，（８）式〜（１５）式に示すフタロシアニン化合物を合成し，クロロホルムに溶解させ，スピンコーティング法によりガラス基板上に薄膜を形成した。
【０１４７】
【化１０】

【０１４８】
【化１１】

【０１４９】
【化１２】

【０１５０】
【化１３】

【０１５１】
【化１４】

【０１５２】
【化１５】

【０１５３】
【化１６】

【０１５４】
【化１７】

【０１５５】
同様に，これら比較例の化合物の分光特性を測定した結果を図１４〜図２０に示す。図１４〜図２０から，初期的に色素分子がランダムに凝集していると推測される。なぜなら，初期の吸収スペクトルのピークが１つで，吸収スペクトル幅が狭いからである。
【０１５６】
なお，図１４は（８）式のＳｉＰｃ［−ＯＳｉ（ＣＨ_３ ）_２ Ｃ_４ Ｈ_９ ］_２ ，図１５は，（９）式のＳｉＰｃ［−ＯＳｉ（ＣＨ_３ ）_２ Ｃ_５ Ｈ_１１］_２ ，図１６は，（１０）式のＳｉＰｃ［−ＯＳｉ（ＣＨ_３ ）_２ Ｃ_６ Ｈ_１３］２，図１７は，（１１）式のＳｉＰｃ［−ＯＳｉ（ＣＨ_３ ）_２ Ｃ_８ Ｈ_１７］_２ ，図１８は，（１２）式のＳｉＰｃ［−ＯＳｉ（ＣＨ_３ ）_２ Ｃ_１０Ｈ_２１］_２ ，図１９は，（１３）式のＳｉＰｃ［−ＯＳｉ（ＣＨ_３ ）_２ Ｃ_１２Ｈ_２５］_２ ，図２０は，（１４）式のＳｉＰｃ［−ＯＳｉ（Ｃ_２ Ｈ_５ ）_２ Ｃ_８ Ｈ_１７］_２ の薄膜吸収スペクトルをそれぞれ示している。
【０１５７】
（１５）式のＳｉＰｃ［−ＯＳｉ（ｉ−Ｃ_３ Ｈ_７ ）_２ Ｃ_８ Ｈ_１７］_２ の薄膜吸収スペクトルについては図示していないが，初期（成膜時）から相分離しており，吸収スペクトル変化は図２０に示す（１４）式のＳｉＰｃ［−ＯＳｉ（Ｃ_２ Ｈ_５ ）_２ Ｃ_８ Ｈ_１７］_２ の吸収スペクトル変化と同様であった。
【０１５８】
これら比較例の色素は初期的あるいは加熱によって色素が相分離又は結晶化を起こし，膜質は不良であった。これについても置換基の凝集力及び空間的広がりによる特有の効果により生じているものと考えられる。
【０１５９】
また，比較例の化合物は，１００℃，１５０℃，１８０℃，２００℃の加熱では吸光度の急激な低下が起きてしまい，吸収スペクトルがシフトしなかった。
【０１６０】
以上より，（７）式に示す実施例の化合物が，その色素構造により規則的な１つ以上の色素凝集状態を形成させる特有の効果があり，かつ加熱によりその凝集状態を大きく変化させ，別の凝集状態へと変化させることができることがわかった。更に，この加熱による凝集状態の変化に伴い，複数の波長域で吸収スペクトル変化が生じており，複数の異なる波長域から選択された波長のレーザ光で情報の記録及び再生が可能で，かつ，ある波長で記録した情報を，複数の異なる再生波長で再生できることが可能であることがわかった。
【０１６１】
更に，（７）式の構造を有する色素が，ＣＤ系メディアとＤＶＤ系メディア，即ち記録，再生波長として７８０ｎｍ近傍を利用する光情報記録媒体と６３０ｎｍ近傍を利用する光情報記録媒体間で互換性を有するメディアとして利用することができる特性を有する否かを以下に確かめた。
【０１６２】
スピンコート法により，（７）式においてｎ＝１１の色素（図９参照）の薄膜をガラス基板上に形成し，更にその上に金を蒸着したサンプルを作成した。
【０１６３】
このときのサンプルの反射率は，図２１の実線に示される通りであり，７８０ｎｍで反射率約７９％，６３５ｎｍで反射率約５７％であり，高反射型ＣＤ，ＤＶＤ系メディアとして利用可能であることがわかった。
【０１６４】
次に，このサンプルを１８０℃で５分加熱したときの反射率を図２１の破線で示す。この結果から明らかなように，７８０ｎｍ近傍，６５０ｎｍ近傍共に，加熱記録によって反射率が低下していることがわかった。加熱記録による反射率変化は，７８０ｎｍで７９％から３７％への変化，６３５ｎｍで５７％から４６％への変化であった。
【０１６５】
上述したように，加熱によって６５０ｎｍ近傍及び７８０ｎｍ近傍の両方の吸収スペクトルを変化させることができたことは，ある任意のこの色素が吸収する波長のレーザ光を照射すれば，その吸収加熱効果により，図２１と同様な反射率変化が得られることがわかる。すなわち，７６０ｎｍ〜８３０ｎｍの記録波長で記録しても，６２０〜６５０の記録波長で記録しても，７６０ｎｍ〜８３０ｎｍと６２０ｎｍ〜６５０ｎｍ近傍の両方の吸収スペクトルを同時に変化させることができる。また，７６０ｎｍ〜８３０ｎｍ又は６２０ｎｍ〜６５０ｎｍから選択された任意の記録波長で記録された情報は，７６０ｎｍ〜８３０ｎｍの再生波長でも，６２０ｎｍ〜６５０ｎｍの再生波長でも記録された情報を未記録状態に対して，反射率が低下する情報として再生することができることが明らかになった。
【０１６６】
【発明の効果】
以上説明したように，本発明に係る光情報記録媒体（請求項１）によれば，色素が，一般式
【化１８】

で表されるフタロシアニン化合物であるため，大きなスペクトルシフトを得ることができ，複数の異なる波長域から選択された波長のレーザ光で情報の記録及び再生を行うことができる。したがって，複数の光情報記録媒体間，複数の光情報記録媒体用ドライブ間で情報の共有化を図ることができると共に，常に変化し氾濫する光情報記録媒体の資源共有化を図ることができ，互換性の高い光情報記録媒体を得ることができ，色素が，外部エネルギーの付加によって凝集状態が変化し，複数の異なる波長域に対する吸収スペクトルが変化するものであるため，複数の異なる波長域から選択された波長のレーザ光で情報の記録及び再生を行うことができる。また，色素の凝集状態を変化させるのみであるため，低パワーのレーザ光を情報の記録及び再生に用いることができる。したがって，複数の光情報記録媒体間，複数の光情報記録媒体用ドライブ間で情報の共有化を図ることができると共に，常に変化し氾濫する光情報記録媒体の資源共有化を図ることができ，互換性の高い光情報記録媒体を得ることができる。
【０１６７】
また，本発明に係る光情報記録媒体（請求項２）によれば，請求項１記載の光情報記録媒体において，記録層が，色素の凝集状態の変化により，色素の凝集状態の変化前の反射率と比較して，複数の異なる波長域から選択された全ての光に対する反射率を低下させることによって情報を記録するものであるため，複数の異なる波長域から選択された波長のレーザ光で情報の記録及び再生を行うことができる。また，色素の凝集状態を変化させるのみであるため，低パワーのレーザ光を情報の記録及び再生に用いることができる。したがって，複数の光情報記録媒体間，複数の光情報記録媒体用ドライブ間で情報の共有化を図ることができると共に，常に変化し氾濫する光情報記録媒体の資源共有化を図ることができ，互換性の高い光情報記録媒体を得ることができる。
【０１６８】
また，本発明に係る光情報記録媒体（請求項３）によれば，請求項１又は２記載の光情報記録媒体において，複数の異なる波長域が，６２０〜６５０ｎｍ及び７６０〜８３０ｎｍであるため，複数の異なる波長域から選択された波長のレーザ光で情報の記録及び再生を行うことができる。したがって，複数の光情報記録媒体間，複数の光情報記録媒体用ドライブ間で情報の共有化を図ることができると共に，常に変化し氾濫する光情報記録媒体の資源共有化を図ることができ，互換性の高い光情報記録媒体を得ることができる。
【０１６９】
また，本発明に係る光情報記録媒体（請求項４）によれば，請求項３記載の光情報記録媒体において，６２０〜６５０ｎｍの波長域から選択された波長のレーザ光で情報の記録及び再生が可能であり，かつ７６０〜８３０ｎｍの波長域から選択された波長のレーザ光で情報の記録及び再生が可能であるため，複数の光情報記録媒体間，複数の光情報記録媒体用ドライブ間で情報の共有化を図ることができると共に，常に変化し氾濫する光情報記録媒体の資源共有化を図ることができ，互換性の高い光情報記録媒体を得ることができる。
【０１７０】
また，本発明に係る光情報記録媒体（請求項５）によれば，請求項４記載の光情報記録媒体において，更に，６２０〜６５０ｎｍ又は７６０〜８３０ｎｍのいずれか一方の波長域から選択された波長のレーザ光によって記録された情報が，６２０〜６５０ｎｍ及び７６０〜８３０ｎｍの波長域から選択された全ての波長のレーザ光で再生可能であるため，複数の光情報記録媒体間，複数の光情報記録媒体用ドライブ間で情報の共有化を図ることができると共に，常に変化し氾濫する光情報記録媒体の資源共有化を図ることができ，互換性の高い光情報記録媒体を得ることができる
【０１７２】
また，本発明に係る光情報記録媒体の情報記録方法（請求項６）によれば，請求項１〜５のいずれかに記載の光情報記録媒体の記録層に対して外部エネルギーを付加して，色素の凝集状態を変化させ，複数の異なる波長域の吸収スペクトルを，外部エネルギー付加前の吸収スペクトルから異なる吸収スペクトルに変化させることによって記録層に情報を記録するため，複数の異なる波長域から選択された波長のレーザ光で情報の記録を行うことができる。また，色素の凝集状態を変化させるのみであるため，低パワーのレーザ光を情報の記録及び再生に用いることができる。したがって，複数の光情報記録媒体間，複数の光情報記録媒体用ドライブ間で情報の共有化を図ることができると共に，常に変化し氾濫する光情報記録媒体の資源共有化を図ることができ，互換性の高い光情報記録媒体の情報記録方法を得ることができる。
【０１７３】
また，本発明に係る光情報記録媒体の情報記録方法（請求項７）によれば，請求項６記載の光情報記録媒体の情報記録方法において，複数の異なる波長域から選択された全ての波長の光に対する反射率を，吸収スペクトル変化前の反射率から低下させることによって記録層に情報を記録するため，複数の異なる波長域から選択された波長のレーザ光で情報の記録を行うことができる。また，色素の凝集状態を変化させるのみであるため，低パワーのレーザ光を情報の記録及び再生に用いることができる。したがって，複数の光情報記録媒体間，複数の光情報記録媒体用ドライブ間で情報の共有化を図ることができると共に，常に変化し氾濫する光情報記録媒体の資源共有化を図ることができ，互換性の高い光情報記録媒体の情報記録方法を得ることができる。
【０１７４】
また，本発明に係る光情報記録媒体の情報記録方法（請求項８）によれば，請求項６又は７記載の光情報記録媒体の情報記録方法において，複数の異なる波長域が，６２０〜６５０ｎｍ及び７６０〜８３０ｎｍであるため，複数の光情報記録媒体間，複数の光情報記録媒体用ドライブ間で情報の共有化を図ることができると共に，常に変化し氾濫する光情報記録媒体の資源共有化を図ることができ，互換性の高い光情報記録媒体の情報記録方法を得ることができる。
【０１７５】
また，本発明に係る光情報記録媒体の情報再生方法（請求項９）によれば，請求項１〜５のいずれかに記載の光情報記録媒体において，外部エネルギーを付加することによって吸収スペクトルが変化する複数の異なる波長域から選択された波長の光を用いて，記録層に記録された情報を再生するため，複数の異なる波長域から選択された波長のレーザ光で情報の再生を行うことができる。したがって，複数の光情報記録媒体間，複数の光情報記録媒体用ドライブ間で情報の共有化を図ることができると共に，常に変化し氾濫する光情報記録媒体の資源共有化を図ることができ，互換性の高い光情報記録媒体の情報再生方法を得ることができる。
【０１７６】
また，本発明に係る光情報記録媒体の情報再生方法（請求項１０）によれば，請求項９記載の光情報記録媒体の情報再生方法において，記録層に複数の異なる波長域から選択された波長の光を照射してその反射光を受光し，記録層に情報が記録されていない状態の反射率に対する反射率の低下を検出することによって記録層に記録された情報を再生することにしたため，複数の異なる波長域から選択された波長のレーザ光で情報の再生を行うことができる。したがって，複数の光情報記録媒体間，複数の光情報記録媒体用ドライブ間で情報の共有化を図ることができると共に，常に変化し氾濫する光情報記録媒体の資源共有化を図ることができ，互換性の高い光情報記録媒体の情報再生方法を得ることができる。
【０１７７】
更に，本発明に係る光情報記録媒体の情報再生方法（請求項１１）によれば，請求項９又は１０記載の光情報記録媒体の情報再生方法において，複数の異なる波長域が，６２０〜６５０ｎｍ及び７６０〜８３０ｎｍであるため，複数の光情報記録媒体間，複数の光情報記録媒体用ドライブ間で情報の共有化を図ることができると共に，常に変化し氾濫する光情報記録媒体の資源共有化を図ることができ，互換性の高い光情報記録媒体の情報再生方法を得ることができる。
【図面の簡単な説明】
【図１】記録層に用いる色素の吸収スペクトルのシフトを説明するための説明図である。
【図２】記録層に用いる色素の吸収スペクトルのシフトを説明するための説明図である。
【図３】記録層に用いる色素の吸収スペクトルのシフトを説明するための説明図である。
【図４】フタロシニアン，ナフタロシニアン等の化合物の主骨格の位置と吸収スペクトルの変化量を説明するための説明図である。
【図５】フタロシニアン，ナフタロシニアン等の化合物の主骨格の位置によるエネルギー変化を説明するための説明図である。
【図６】記録層に用いる色素の吸収スペクトルのシフトを説明するための説明図である。
【図７】記録層に用いる色素の吸収スペクトルのシフトを説明するための説明図である。
【図８】本発明に係る光情報記録媒体に用いる色素化合物の実施例（（７）式，ｎ＝７）の分光特性を説明する説明図である。
【図９】本発明に係る光情報記録媒体に用いる色素化合物の実施例（（７）式，ｎ＝１１）の分光特性を説明する説明図である。
【図１０】本発明に係る光情報記録媒体に用いる色素化合物の実施例（（７）式，ｎ＝７）をクロロホルム溶液に溶解させた場合の吸収スペクトルを説明する説明図である。
【図１１】本発明に係る光情報記録媒体に用いる色素化合物の実施例（（７）式，ｎ＝１１）をクロロホルム溶液に溶解させた場合の吸収スペクトルを説明する説明図である。
【図１２】本発明に係る光情報記録媒体に用いる色素化合物の実施例（（７）式，ｎ＝７）をクロロホルム溶液からスピンコーティング法により薄膜化させ，初期状態，１００℃，１５０℃，１８０℃，２００℃に加熱したときの吸収スペクトルを説明する説明図である。
【図１３】本発明に係る光情報記録媒体に用いる色素化合物の実施例（（７）式，ｎ＝１１）をクロロホルム溶液からスピンコーティング法により薄膜化させ，初期状態，１００℃，１５０℃，１８０℃，２００℃に加熱したときの吸収スペクトルを説明する説明図である。
【図１４】光情報記録媒体に用いる色素化合物の比較例（（８）式）をクロロホルム溶液からスピンコーティング法により薄膜化させ，初期状態，１００℃，１５０℃，１８０℃，２００℃に加熱したときの吸収スペクトルを説明する説明図である。
【図１５】光情報記録媒体に用いる色素化合物の比較例（（９）式）をクロロホルム溶液からスピンコーティング法により薄膜化させ，初期状態，１００℃，１５０℃，１８０℃，２００℃に加熱したときの吸収スペクトルを説明する説明図である。
【図１６】光情報記録媒体に用いる色素化合物の比較例（（１０）式）をクロロホルム溶液からスピンコーティング法により薄膜化させ，初期状態，１００℃，１５０℃，１８０℃，２００℃に加熱したときの吸収スペクトルを説明する説明図である。
【図１７】光情報記録媒体に用いる色素化合物の比較例（（１１）式）をクロロホルム溶液からスピンコーティング法により薄膜化させ，初期状態，１００℃，１５０℃，１８０℃，２００℃に加熱したときの吸収スペクトルを説明する説明図である。
【図１８】光情報記録媒体に用いる色素化合物の比較例（（１２）式）をクロロホルム溶液からスピンコーティング法により薄膜化させ，初期状態，１００℃，１５０℃，１８０℃，２００℃に加熱したときの吸収スペクトルを説明する説明図である。
【図１９】光情報記録媒体に用いる色素化合物の比較例（（１３）式）をクロロホルム溶液からスピンコーティング法により薄膜化させ，初期状態，１００℃，１５０℃，１８０℃，２００℃に加熱したときの吸収スペクトルを説明する説明図である。
【図２０】光情報記録媒体に用いる色素化合物の比較例（（１４）式）をクロロホルム溶液からスピンコーティング法により薄膜化させ，初期状態，１００℃，１５０℃，１８０℃，２００℃に加熱したときの吸収スペクトルを説明する説明図である。
【図２１】本発明に係る光情報記録媒体に用いる色素化合物の実施例（（７）式，ｎ＝１１）を用いた場合の反射率の変化を説明するための説明図である。
【図２２】ＣＤ−Ｒに情報を書き込んだ状態を説明するための説明図である。
【符号の説明】
１ 基板
２ 記録層
３ 金反射面[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical information recording medium, an information recording method of the optical information recording medium, and an information reproducing method, and more particularly, to sharing information between a plurality of optical information recording media and a plurality of optical information recording medium drives. The present invention relates to an optical information recording medium, an information recording method for an optical information recording medium, and an information reproducing method capable of sharing resources of an optical information recording medium that constantly changes and overflows.
[0002]
[Prior art]
At present, a number of removable disks have appeared as data storage media for personal computers. Among these, the CD-ROM has completely established one position, as in the past FDD, and the CD-ROM drive is being installed as a standard in most personal computers. The compatibility with the CD-ROM media is even one of the differentiating factors of the removable media.
[0003]
For example, a CD-R (CD-Recordable), which is a CD-based write-once medium, has a reflectance of 60 to 70% or more in an unrecorded state so that it can be reproduced by a CD-ROM drive. Recording can be performed by lowering the reflectance by recording. With this compatibility, information recorded on a CD-R can be read by a CD-ROM drive.
[0004]
That is, in a CD-R, a recording layer, a reflection layer, and a protective layer are laminated on a transparent resin substrate, and the recording layer undergoes physical or chemical changes by irradiating the recording layer with a high-power laser beam. Wake up and record information in the form of pits. Then, by irradiating the formed pits with a low-power laser beam and detecting a change in reflectance, information recorded as pits can be reproduced.
[0005]
In recent years, research and development of removable media as gigabyte storage, such as HDDs, have been actively conducted, and CD media have begun to evolve into DVD (digital video disc) media. In this DVD-based medium, a laser beam having a wavelength of 630 nm is used for recording / reproducing information with respect to a laser beam having a wavelength of 780 nm used for recording / reproducing of current CD-based media. Further, even in the case of DVD media, a DVD-ROM is required to have a high reflectance of 60 to 70% or more when not recorded, like a CD-ROM.
[0006]
Therefore, it can be easily imagined that compatibility between the CD-based media and the DVD-based media becomes very problematic. There is no problem with the compatibility between the CD-ROM and the DVD-ROM, but this problem exists as a major hurdle in the write-once CD-R.
[0007]
At present, CD-Rs are gradually becoming popular due to their high compatibility and ease of handling. However, since the recording / reproducing wavelength of CD-R and the recording / reproducing wavelength of DVD-based media are different, CD-R media It is very inconvenient for the user that the information recorded in the DVD cannot be read by the DVD drive. This is because both CD-Rs and DVD-ROMs may become popular in the future. Therefore, it is clear that it is preferable to introduce a CD-R that can be reproduced by a DVD drive into the market.
[0008]
As described above, the current CD-R records and reproduces information using a laser wavelength of 780 nm. Specifically, in order to make the current CD-R compatible with DVD-based media so that the information written on the CD-R can be reproduced by a DVD-based drive, 635 nm of the recording material of the CD-R is used. It is necessary to make the recorded information exist near the wavelength of. In other words, when recording information on a CD-R, it is necessary to change the physical properties of the dye near 780 nm and also the physical properties of the dye near 635 nm.
[0009]
At present, a cyanine-based or phthalocyanine-based dye is used in a recording layer of a CD-R. The information is written as a change in reflectance (decrease in reflectance) due to a change in physical properties of the dye such as decomposition of these dyes, deformation of the substrate, and the like.
[0010]
FIG. 22 is an explanatory diagram for explaining a state where information has been written to a CD-R. FIG. 22A shows the state of a CD-R before information is recorded. This CD-R is composed of a substrate 1, a recording layer 2 formed on the substrate 1 and containing a dye, and a recording layer 2. 2 and a gold reflection layer 3 formed on the metal layer 2.
[0011]
As a method of actually recording information on a CD-R, as shown in FIG. 22, a method of forming a bump by deforming the interface between the recording layer 2 containing the dye and the substrate 1 (FIG. 22B )), A method of forming Pits (pits) at the interface between the recording layer 2 containing the dye and the gold reflective layer 3 (FIG. 22C), or a bubble at the interface between the recording layer 2 containing the dye and the gold reflective layer 3 There is a method of forming (bubbles) (FIG. 22D). For reference, FIG. 22E shows a state where information is recorded on a CD-ROM.
[0012]
By the way, the current CD-R uses the long wavelength side of the absorption spectrum of a cyanine dye or a phthalocyanine dye as a recording / reproducing wavelength. By using the wavelength in this region, appropriate absorption and reflectance can be obtained. That is, a high reflectance is obtained when recording is not performed, and a change in the physical properties of the dye due to heat absorption, a change in the interface of the substrate or the interface of the gold reflective layer is caused during recording, and the reflectance can be reduced to record information.
[0013]
Therefore, as one method for making it possible to read information recorded at wavelengths of 780 nm and 635 nm with a laser beam of 780 nm, which is the recording / reproducing wavelength of a CD-R, a dye of 780 nm wavelength is used. A method is conceivable in which the dye whose absorption spectrum is located at the hem (longer wavelength side) and the hem of the absorption spectrum of the dye is also located at the wavelength of 635 nm (short wavelength side) is used for the recording layer. .
[0014]
An optical recording medium disclosed in Japanese Patent Application Laid-Open No. 7-323665, for example, enables recording and reproduction of information in different wavelength ranges. This optical recording medium is an optical recording medium in which a recording layer containing a dye, a reflective layer and a protective layer are sequentially laminated on a substrate, wherein the recording layer has an absorption maximum of less than 630 nm and is selected from 630 to 690 nm. The absorbance of light having a wavelength selected is 0.03 to 0.5, and the absorbance of light having a wavelength selected from 770 to 830 nm is 0.03 to 0.3.
[0015]
According to this optical recording medium, recording / reproduction can be performed with respect to red laser light having a wavelength selected from 630 to 690 nm, and near-infrared laser light having a wavelength selected from 770 to 830 nm can be obtained. And an optical recording medium having good recording characteristics capable of recording / reproducing or reproducing in accordance with the CD standard.
[0016]
Another example is an optical recording medium disclosed in JP-A-8-31010. This optical recording medium comprises at least a light absorbing layer provided on a transparent substrate, directly or through another layer, for absorbing laser light, and a light reflecting layer provided directly on the light absorbing layer. In the optical recording medium, the light absorbing layer contains at least an organic dye, the light reflecting layer is formed of a metal film, and recording and reproduction can be performed by using the wavelength λ1 of the laser beam. Recording and reproduction are possible using the wavelength λ2 of the laser light of the above, and the refractive index of the light absorbing layer at the wavelength λ1 is 1.8 to 2.6, and the extinction coefficient k is 0.04 to 0.16. In this case, the refractive index of the light absorbing layer at the wavelength λ2 is 1.6 or more, and the extinction coefficient k is 0.04 to 0.5.
[0017]
According to this optical recording medium, recording and reproduction in accordance with the CD standard can be performed for near-infrared laser light having a different wavelength, for example, a wavelength selected from 770 to 830 nm. It is possible to obtain an optical recording medium having good recording characteristics and capable of recording and reproducing or reproducing with respect to a red laser beam having a predetermined wavelength.
[0018]
[Problems to be solved by the invention]
However, in the optical recording media disclosed in the above two publications, bumps or the like are formed at the interface between the recording layer 2 containing the dye and the gold reflective layer 3 or the recording layer 2 containing the dye and the substrate 1 as shown in FIG. Since information is recorded on a CD-R by forming a recording portion, when a laser beam having a wavelength of 780 nm is used, bumps or the like are used as recording information and the difference in reflectance from an unrecorded portion is sufficient. Although information can be reproduced with contrast, when a laser beam having a wavelength of 630 nm is used, a difference in reflectance from an unrecorded portion cannot be obtained with sufficient contrast, and information may not be reproduced accurately. There is.
[0019]
This is because in a CD or DVD medium, a method is used in which incident laser light is diffracted or scattered by a recording unit and information is reproduced based on the amount of diffracted or scattered light incident on the objective lens. is there. Specifically, in a CD-based or DVD-based medium, no bump or the like is formed in an unrecorded portion, and a laser beam for reproducing information is not diffracted or scattered. The emitted laser light returns almost as it is. On the other hand, when a recording portion such as a bump is formed, laser light for reproducing information is diffracted or scattered by the recording portion, so that the amount of light returning to the detector decreases. As described above, in the CD-based and DVD-based media, the information is reproduced by utilizing the fact that the amount of the incident laser light is reduced and returned.
[0020]
As described above, in the conventional optical information recording medium, a fine recording portion is formed at the interface between the recording layer containing the dye itself, the recording layer containing the dye and the gold reflective layer, or the recording layer containing the dye and the substrate. Therefore, the light having a wavelength of 780 nm is sufficiently diffracted or scattered by the formed recording portion, so that the amount of return light is reduced. There is a possibility that the light quantity does not sufficiently decrease.
[0021]
Further, with the current dye for CD-R, even if information can be recorded / reproduced with a laser beam having a wavelength of 780 nm, it is difficult to reproduce information recorded with a laser beam having a wavelength of 635 nm. This is, on the one hand, a problem of the recording mechanism itself as described above, and the other is the low reflectivity around 635 nm. Due to the low reflectivity, it is difficult to detect a signal, and the error rate and the jitter increase. Therefore, a certain degree of reflectance is required not only near 780 nm but also near 635 nm.
[0022]
Therefore, the present invention has been made in view of the above, and shares information among a plurality of optical information recording media or a plurality of optical information recording medium drives, and constantly changes and floods the optical information recording medium. The purpose is to share resources.
[0023]
[Means for Solving the Problems]
The inventor of the present invention has developed an optical information recording medium that changes only the physical properties of dyes in a plurality of reproduction wavelength regions during recording without changing the shapes of the recording layer containing the dye, the gold reflective layer, and the substrate. , Found that the above objectives can be achieved. That is, the optical information recording medium according to claim 1 of the present invention is an optical information recording medium comprising a substrate and a recording layer containing at least a dye and a reflective layer laminated on the substrate.The dye has a general formula
Embedded image

(However, X ¹ ~ X ^Four Are each independently a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, an alkoxy group which may have a substituent, An aryloxy group, an alkylthio group which may have a substituent, an arylthio group which may have a substituent, a nitro group, a cyano group, a sulfonic acid group, a sulfonamide group, and a sulfonate group. o, p, q, and r are the substituents X ¹ ~ X ^Four Is an integer of 0 to 4. ) Is a phthalocyanine compound represented byThe aggregation state of the dye is changed by the addition of external energy, and the absorption spectrum in a plurality of different wavelength ranges is changed.
[0024]
Also, in the optical information recording medium according to claim 2 of the present invention, in the optical information recording medium according to claim 1, the recording layer is provided before the change in the aggregation state of the dye due to the change in the aggregation state of the dye. Information is recorded and reproduced by lowering the reflectivity for all light selected from the plurality of different wavelength ranges as compared with the reflectivity.
[0025]
An optical information recording medium according to claim 3 of the present invention is the optical information recording medium according to claim 1 or 2, wherein the plurality of different wavelength ranges are 620 to 650 nm and 760 to 830 nm.
[0026]
The optical information recording medium according to claim 4 of the present invention can record and reproduce information with the laser light having a wavelength selected from the wavelength range of 620 to 650 nm in the optical information recording medium according to claim 3. And information can be recorded and reproduced with a laser beam having a wavelength selected from the wavelength range of 760 to 830 nm.
[0027]
An optical information recording medium according to a fifth aspect of the present invention is the optical information recording medium according to the fourth aspect, further comprising a wavelength selected from one of the wavelength ranges of 620 to 650 nm or 760 to 830 nm. Can be reproduced by laser light of all wavelengths selected from the wavelength ranges of 620 to 650 nm and 760 to 830 nm.
[0029]
Claims of the present invention6The information recording method for an optical information recording medium according to1-5In the information recording method for an optical information recording medium according to any one of the above, external energy is added to the recording layer to change the aggregation state of the dye, and the absorption spectra of the plurality of different wavelength ranges are changed. Information is recorded on the recording layer by changing the absorption spectrum before adding external energy to a different absorption spectrum.
[0030]
Claims of the present invention7The information recording method for an optical information recording medium according to6In the information recording method for an optical information recording medium according to the above, the reflectivity for light of all wavelengths selected from the plurality of different wavelength ranges is reduced from the reflectivity before the change of the absorption spectrum, whereby information is recorded on the recording layer. Is to be recorded.
[0031]
Claims of the present invention8The information recording method for an optical information recording medium according to6 or 7In the information recording method for an optical information recording medium described above, the plurality of different wavelength ranges are 620 to 650 nm and 760 to 830 nm.
[0032]
Claims of the present invention9The method for reproducing information from an optical information recording medium according to1-5In the information reproducing method for an optical information recording medium according to any one of the above, the light recorded on the recording layer using light selected from a plurality of different wavelength ranges in which an absorption spectrum changes by adding the external energy. This is for reproducing information.
[0033]
Claims of the present invention10The method for reproducing information from an optical information recording medium according to9In the information reproducing method for an optical information recording medium according to the above, the recording layer is irradiated with light selected from the plurality of different wavelength ranges, the reflected light is received, and the information is not recorded on the recording layer. The information recorded on the recording layer is reproduced by detecting a decrease in the reflectance with respect to the reflectance.
[0034]
Further, the claims of the present invention11The method for reproducing information from an optical information recording medium according to9 or 10In the information reproducing method for an optical information recording medium described above, the plurality of different wavelength ranges are 620 to 650 nm and 760 to 830 nm.
[0035]
That is, the optical information recording medium according to the present invention is characterized in that information can be recorded and reproduced with laser light selected from a plurality of different wavelength ranges. The laser light selected from a plurality of different wavelength ranges is, for example, when there are two different wavelength ranges, the recording wavelength λ of one laser light_w ¹And the other recording wavelength λ_w ², The reproduction wavelength λ of one laser beam_r ¹And the other reproduction wavelength λ_r ²Are different from each other. That is, λ_w ¹≠ λ_w ²≠ λ_r ¹≠ λ_r ²But it's fine. Normally, the same wavelength is used for the recording wavelength and the reproduction wavelength._w ¹= Λ_r ¹≠ λ_w ²= Λ_r ²It becomes.
[0036]
Further, an optical information recording medium according to the present invention is such that information recorded by a laser beam of a certain wavelength can be reproduced by laser beams of two or more different wavelengths. For example, if there are two different recording wavelengths and two different reproduction wavelengths,_w ¹Or λ_w ²The information recorded in_r ¹And λ_r ²Reproduction can be performed by using any of the above.
[0037]
Specifically, the optical information recording medium according to the present invention can record information with a laser beam having a wavelength selected from the wavelength range of 760 to 830 nm, and the recorded information is selected from the wavelength range of 760 to 830 nm. Information can be reproduced with a laser beam having a different wavelength (the recording wavelength and the reproduction wavelength may be different), and information can be recorded with a laser beam having a wavelength selected from a wavelength range of 620 to 650 nm. It can be reproduced with a laser beam having a wavelength selected from the wavelength range of 620 to 650 nm (the recording wavelength and the reproduction wavelength may be different). In addition, information recorded by a laser beam having a wavelength selected from the wavelength range of 760 to 830 nm is reproduced by a laser beam having a wavelength range different from this wavelength range, for example, a wavelength selected from the wavelength range of 620 to 650 nm. can do. Further, information recorded with a laser beam having a wavelength selected from the wavelength range of 620 nm to 650 nm can be reproduced with a laser beam selected from a wavelength range different from this wavelength range, for example, a wavelength range of 760 to 830 nm. it can.
[0038]
In the optical information recording medium according to the present invention, the absorption spectrum near 760 to 830 nm and 620 to 650 nm is changed by recording information with a laser beam having a wavelength selected from the wavelength range of 760 to 830 nm and 620 to 650 nm. be able to. The information is obtained by lowering the reflectance when a laser beam having a wavelength selected from the wavelength range of 760 to 830 nm and 620 to 650 nm is applied to the reflectance when no information is recorded. Be recorded.
[0039]
Thus, by irradiating a laser beam of a wavelength selected from the wavelength range of 620 to 650 nm and detecting a decrease in the reflectance of the received reflected light, the laser beam of the wavelength selected from the wavelength range of 760 to 830 nm is detected. The recorded information can be reproduced. Further, by irradiating a laser beam having a wavelength selected from the wavelength range of 760 to 830 nm and detecting a decrease in the reflectance of the received reflected light, the laser beam having a wavelength selected from the wavelength range of 620 to 650 nm is used. The recorded information can be reproduced.
[0040]
As described above, it is possible to irradiate a laser beam having a certain wavelength to change the absorption spectrum in a plurality of wavelength ranges and to reduce the reflectance for a laser beam having a wavelength selected from the plurality of wavelength ranges. This is a characteristic of the optical information recording medium. The change in the absorption spectrum is caused by the change in the aggregation state of the dye in the recording layer. The inventor of the present invention has found a dye capable of changing the state of aggregation of the dye, changing the absorption spectrum in the wavelength range of 620 to 650 nm and 760 to 830 nm, and reducing the reflectance. The structure of the dye is shown by the above chemical formula.
[0041]
In the information recording method for an optical information recording medium according to the present invention, the state of aggregation of the dye molecules is controlled by external energy to change the absorption spectrum. Changes in the absorption spectrum include an increase or decrease in absorbance due to a phase change or crystallization of the dye, an increase or decrease in the absorbance of the dye, a hyperchromic effect or a hypochromic effect, or an aggregation state in which the absorption spectrum shifts. There is a change, a deep-color shift, a deep-color shift, and the like.
[0042]
The shape change of the absorption spectrum may be any change in the absorption spectrum. However, the change in the physical shape of the dye film due to the decomposition, dissolution, phase change, crystallization, etc. of the dye is a problem of the conventional technology. As described in the point, it is not preferable.
[0043]
Therefore, in the present invention, a method is used in which only the aggregation state of the dye is changed to change the absorption spectrum. This change in the absorption spectrum is accompanied by a so-called shift in the absorption spectrum. However, a change in the absorption spectrum does not necessarily cause only the absorption spectrum shift. The use of the term "spectral shift" here emphasizes that recording can be performed without changing the shape of the recording layer or the like as shown in FIG. In other words, it means that an absorption spectrum change occurs without a physical change of the recording layer containing the dye. The terms absorption spectrum shift or change in absorption spectrum used hereinafter are all used to mean changes in the absorption spectrum without physical changes such as the shape state of the dye. However, the recording layer used in the present invention can record / reproduce information by a change in the absorption spectrum without a physical change such as a shape state. However, in an actual optical disk, a physical change of a substrate or the like as shown in FIG. Is not refused to be added to the change in the absorption spectrum of the present invention. The point is that the recording layer of the optical information recording medium of the present invention does not need to be physically changed, such as a substrate, as in the related art.
[0044]
In the optical information recording medium of the present invention, information is recorded by causing the absorption spectrum shift to occur simultaneously in at least two or more different wavelength ranges. The absorption spectrum shift refers to a shift of the entire absorption spectrum caused by application of one external energy, for example, irradiation of a laser beam having a certain wavelength, and is not a local absorption spectrum shift. Therefore, by using this recording method, information can be recorded at two or more different recording wavelengths, and information recorded at two or more different reproduction wavelengths can be reproduced.
[0045]
FIG. 1 is an explanatory diagram for explaining the shift of the absorption spectrum. In FIG. 1, on the long wavelength side with respect to the peak wavelength of the absorption spectrum, the absorption spectrum is shifted by changing the aggregation state of the dye. On the other hand, on the short wavelength side with respect to the peak wavelength of the absorption spectrum, the absorption spectrum is increased by changing the aggregation state of the dye. When laser light of both the long wavelength and the short wavelength where the absorption spectrum is changed is irradiated, the information can be recorded by reducing the reflectance of the laser light. it can.
[0046]
In FIG. 1, it is assumed that the reproduction wavelength exists on the long wavelength side and the short wavelength side with respect to the peak wavelength of the dye. However, even if the two reproduction wavelengths are on the long wavelength side, they are on the short wavelength side. Is also good.
[0047]
Therefore, according to this information recording method, information can be recorded with two light beams having different wavelengths, and the recording lowers the reflectivity for a laser beam having a reproduction wavelength with respect to a state where no information is recorded. be able to. Therefore, information recorded at a certain wavelength can be reproduced with two or more laser beams having different wavelengths. Since this reproduction method uses the same method as CD-based media in which the reflectance is reduced by recording information, it can have compatibility with other CD-based media.
[0048]
Specifically, in the optical information recording medium according to the present invention, by recording information with a laser beam having a wavelength selected from the wavelength range of 760 to 830 nm and 620 to 650 nm, the wavelength range of 760 to 830 nm and 620 to 650 nm is recorded. Changes the nearby absorption spectrum. Information is recorded by utilizing the fact that the reflectivity for laser light having a wavelength selected from the wavelength range of 760 to 830 nm and 620 to 650 nm is lower than the reflectivity in a state where no information is recorded. You.
[0049]
As a result, information recorded with the laser light having a wavelength selected from the wavelength range of 760 to 830 nm is converted into the laser light having the wavelength selected from the wavelength range of 760 to 830 nm and the wavelength selected from the wavelength range of 620 to 650 nm. Even if both laser beams are used, the information can be reproduced as a decrease in the reflectance with respect to the reflectance in the unrecorded state. On the other hand, information recorded with a laser beam having a wavelength selected from the wavelength range of 620 to 650 nm is also used for the laser beam having a wavelength selected from the wavelength range of 760 to 830 nm and a wavelength selected from the wavelength range of 620 to 650 nm. Even when both of the laser beams are used, information can be reproduced as a decrease in reflectance with respect to the reflectance in an unrecorded state.
[0050]
In this way, laser light of a certain wavelength changes the aggregation state of the dye to change the absorption spectrum in a plurality of wavelength ranges, and the change reduces the reflectivity of the laser light in a plurality of wavelength ranges to obtain information. Recording is a feature of the information recording method of the optical information recording medium of the present invention.
[0051]
Further, in the information reproducing method for an optical information recording medium according to the present invention, the optical information recording medium described above is irradiated with light in a plurality of wavelength ranges that cause a change in the absorption spectrum and reduce the reflectance. Information recorded on the medium can be reproduced.
[0052]
For example, as shown in FIG. 1 described above, by irradiating a laser beam having a wavelength selected from the long wavelength side and the short wavelength side in which the absorption spectrum has changed, two light beams as shown in FIG. Information recorded in different wavelength ranges can be reproduced by detecting a decrease in reflectance. In FIG. 1, the information reproduction has been described assuming that the two reproduction wavelengths of the information are in the wavelength regions on the long wavelength side and the short wavelength side with respect to the peak wavelength of the absorption spectrum. The information can be reproduced even if it exists on one of the long wavelength side and the short wavelength side with respect to the peak wavelength of.
[0053]
As described above, in the optical information recording medium of the present invention, information can be recorded with a laser beam having a wavelength selected from the wavelength range of 760 to 830 nm and 620 to 650 nm, and information of 760 to 830 nm and 620 to 650 nm can be recorded. Changes the absorption spectrum near the wavelength range. Information is recorded by lowering the reflectance near the wavelength range of 760 to 830 nm and 620 to 650 nm with respect to the reflectance in the unrecorded state.
[0054]
As a result, information recorded with the laser light having a wavelength selected from the wavelength range of 760 to 830 nm is converted into the laser light having the wavelength selected from the wavelength range of 760 to 830 nm and the wavelength selected from the wavelength range of 620 to 650 nm. Information can be reproduced as a decrease in the reflectance with respect to the reflectance in an unrecorded state by both of the laser beams. On the other hand, information recorded with a laser beam having a wavelength selected from the wavelength range of 620 to 650 nm is also used for the laser beam having a wavelength selected from the wavelength range of 760 to 830 nm and a wavelength selected from the wavelength range of 620 to 650 nm. With both of the laser beams, information can be reproduced as a decrease in the reflectance with respect to the reflectance in an unrecorded state.
[0055]
As described above, the information recorded as the decrease in reflectance using the change in the absorption spectrum is irradiated with laser light of a wavelength selected from a plurality of wavelength ranges to detect the decrease in reflectance and reproduce the information. This is a feature of the information reproducing method of the optical information recording medium of the present invention.
[0056]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of an optical information recording medium, a recording method of the optical information recording medium, and a reproducing method according to the present invention will be described in detail with reference to the drawings.
[0057]
In the embodiment of the present invention, a write-once optical information recording medium compatible with CD-based media and DVD-based media will be described, in addition to a recordable organic material that is recordable. That is, a write-once optical information recording medium of high sensitivity that can be written only once, such as a CD-R currently on the market and a DVD-R system that will appear in the future, will be described.
[0058]
(Dye used for recording layer)
At present, recording media of CD media, PDs, MDs, MOs and the like have a maximum recording capacity of about 650 MB. An organic material is used for a recordable type, and an inorganic material is used for a rewritable type.
[0059]
From the results of inorganic materials such as phase change materials, it is not conceivable that an organic material is used as a rewritable material in the above capacity. However, with the spread of DVD media in the future, organic materials may be applied not only to write-once media but also to rewritable media.
[0060]
This is because inorganic materials have poor sensitivity, and have a thermal conductivity and thermal diffusion coefficient that are one to two orders of magnitude higher than organic materials. Considering compatibility with ROM, high reflectivity such as ROM may be required for both write-once type and rewritable type. Inorganic materials must achieve such high reflectivity. Is difficult.
[0061]
At present, DVD-ROMs have a capacity of 4.7 GB or more, whereas DVD-RAMs using a phase change material have a capacity of about 2.9 GB even if mark edge recording or land / groove recording is used. . Therefore, the inventor of the present invention has studied using an organic material as a material capable of increasing the sensitivity and the transfer rate.
[0062]
At present, phthalocyanine and naphthalocyanine compounds are one of the most suitable materials for optical information recording media. However, in a CD-R, that is, a type of medium in which a user can write information only once, phthalocyanine and naphthalocyanine compounds are simply used for absorbing laser light when recording information. Then, the information is recorded using decomposition of the phthalocyanine or naphthalocyanine compound by laser light absorption or deformation of the substrate by laser light absorption of the phthalocyanine or naphthalocyanine compound. The state of recording the information by deforming the substrate by the absorption of the laser light is as shown in FIG. 22 described above. The recording mechanism shown in FIG. 22 has a problem that jitter at the time of high-speed reproduction becomes large and a high transfer rate cannot be achieved.
[0063]
In particular, DVD-based media are required to have a high speed at the time of recording as well as a high speed at the time of reproduction. For that purpose, the sensitivity of the recording film is very important. However, when information is recorded by thermal decomposition and thermal deformation as in the current CD-R, a high-output laser is required, which is not preferable in terms of recording response.
[0064]
In addition, since DVD-ROMs have a capacity of 4.7 GB or more in DVD-based media, it is preferable that write-once and rewritable DVDs have the same capacity. However, what is currently in the spotlight as a RAM uses a phase-change type material, and its capacity is only about 2.9 GB even when a mark edge recording or a land / groove type high-density method is used. ing.
[0065]
The reason for this is that inorganic materials are basically insensitive and that the thermal conductivity and the thermal diffusion coefficient are one to two orders of magnitude higher than those of organic materials. Therefore, a recording material capable of recording at high speed with high sensitivity and reproducing information with low jitter is highly desired.
[0066]
In the present invention, instead of using a phthalocyanine or naphthalocyanine compound as a mere absorbing material as in the prior art, the substrate deformation and physical physical properties of the dye are directly utilized by utilizing the change in the physical properties of the phthalocyanine or naphthalocyanine compound itself. An optical information recording medium material that does not involve a change in surface shape due to a change or the like is specified, and an optical information recording medium, an information recording method of the optical information recording medium, and an information reproducing method are provided.
[0067]
A change in the absorption spectrum due to a dye compound such as a phthalocyanine or naphthalocyanine compound is caused by, for example, a change in a crystal state, an aggregation state, an association state, a structure / electronic state, or the like.
[0068]
The change in the absorption spectrum using the change in the aggregation state changes the interaction between the dye molecules. For example, when a dye molecule aggregates in a state where the dye molecule does not interact with another dye molecule alone, that is, in a dispersed state, the absorption spectrum shifts to a short wavelength or a long wavelength. For example, as shown in FIG. 2, the absorption spectrum is shifted from a thick line absorption spectrum to a thin line absorption spectrum.
[0069]
Further, as shown in FIG. 1 described above, the interaction between the dye and the dye changes with respect to the state of aggregation of a certain dye, and the dye aggregate state is different from the aggregation state shown in FIG. Causes a shift to short or long wavelengths.
[0070]
When two or more dye molecules approach a molecular order distance or less, an association phenomenon such as so-called J-association or H-association of the dye is observed. This corresponds to a change in the state of aggregation. In general, the change in crystal state, phase change, and the like are intense due to the surface state of the film and are not suitable for optical memory. Therefore, it is necessary to search for a dye that can change the aggregation state of the dye by external energy.
[0071]
The present invention
(A) Prevents association and aggregation due to forces such as intermolecular force, electrostatic force, and dipole interaction between the basic skeletons of the dye molecules so that the absorption spectrum of the dye molecules cannot be changed by recording;
(B) Initially associated and aggregated to such an extent that the absorption spectrum of the dye molecule can be controlled by recording,
(C) Conversely, the dye molecule prevents dye molecules from interacting with each other even by recording, and is a dye molecule that can be aggregated and aggregated from the beginning to such an extent that the absorption spectrum of the dye molecule can be controlled by recording. A dye having a substituent on the center metal, preferably a dye having a substituent on the central metal, more preferably a dye having an alkyl substituent on the central metal, and the association is caused by the cohesive force of the substituent and the spatial spread of the substituent. Agglomeration causes the effect of the π-conjugated system of the basic skeleton of the dye due to this effect, thereby changing the absorption spectrum of the dye molecule with respect to the state of the dye.
[0072]
Thus, the dye used in the present invention has a substituent on the dye molecule, preferably a substituent on the central metal, and more preferably an alkyl substituent on the central metal.
[0073]
When there is no substituent on the dye molecule (including the substituent substituted on the part other than the central metal) or when the substituent is small, the distance between the dye molecules is small and the interaction force between the dye molecules is large. . For this reason, even if a recording process using external energy is performed, the interaction force cannot be changed, and the absorption spectrum cannot be changed. Therefore, since there is no absorption spectrum mobility, additional writing without a change in the shape of the recording layer cannot be performed.
[0074]
On the other hand, when the substituent is very large three-dimensionally, the interaction between the dye basic skeletons is weakened, and the dye molecules associate and form an aggregated state due to the intermolecular force interaction of the substituent. There is a possibility that the distance between the basic skeletons of the molecules is increased and the interaction between the π-conjugated systems of the basic skeletons of the dye molecules is almost eliminated. Therefore, the change in the interaction between the dye molecules due to the recording is reduced, and the absorption spectrum shift cannot be expected (the difference in the absorption spectrum between one stable dye aggregated state and another stable dye aggregated state is reduced). Therefore, in order to make it possible to change the interaction force between dye molecules by recording (absorption spectrum mobility), the dye molecules are drawn into a range within which a sufficient absorption spectrum shift occurs, and the absorption spectrum In order to have mobility, it is important to keep the dye molecules from coming too close together.
[0075]
Further, in the present invention, a high molecular compound may be added to the coloring matter for the purpose of improving absorption spectrum mobility, reversibility, improving stability, film forming property and film uniformity.
[0076]
In the present invention, the preferred dye structure is such that a substituent is provided on the central metal of the dye molecule so that the dye molecules are not too close to each other, and the dye molecules are drawn into a range within a range that causes a sufficient absorption spectrum shift. That is, the action of the substituent is given to the cohesive force (intermolecular force) of the substituent and the spatial spread of the substituent.
[0077]
Phthalocyanine and naphthalocyanine compounds can be broadly classified according to the location of the substituent.
1) Type having a substituent at the α-position
2) Type having a substituent at the β-position
3) Type having a substituent on the central metal
Can be divided into
[0078]
Of these, phthalocyanine and naphthalocyanine compounds of the type having a substituent at the α-position and the type having a substituent at the β-position have absorption spectra due to the presence of isomers and the presence of energy levels due to the rotation and vibration of the substituent. Easy to spread. Therefore, even if an absorption spectrum change due to a change in aggregation state such as association occurs, the recording contrast is low unless the change is very large (FIG. 3).
[0079]
On the other hand, phthalocyanine and naphthalocyanine compounds of the type having a substituent on the central metal, so-called axial ligands, generally have little effect on the basic skeleton of the phthalocyanine or naphthalocyanine compound due to the influence of the axial ligand. There is almost no difference between the energy states due to the rotation and vibration of the ligand. If a substituent is not introduced at the α-position or β-position, there is no isomer, and thus the absorption spectrum does not spread and shows an absorption spectrum having a sharp peak like a solution state.
[0080]
Therefore, even if the absorption spectrum of such an axial ligand type dye is slightly changed due to the change in the interaction between the dye molecules due to the change of the association and aggregation state, the original (some stable state) Since the absorption spectrum is very sharp, the recording contrast is high (see FIGS. 1 and 2).
[0081]
Further, when the structure is made compatible with CD and DVD media, that is, when a metal reflective layer is provided on the recording layer, a type having a substituent at the α-position and a type having a substituent at the β-position Phthalocyanine and naphthalocyanine compounds have broad absorption spectra and exhibit an absorption spectrum shape that originally includes two stable states of postscript change. In the wavelength region that should not be present in the dye of the main structure, Due to the existence of an energy level due to the presence or the rotation or vibration of the substituent, absorption is relatively large in the recording / reproducing wavelength from the beginning, and the initial (unrecorded, erased) The reflectivity may be reduced.
[0082]
In other words, the recording / reproducing wavelength that increases the reflectivity at the time of unrecording / erasing is selected (there is almost no absorption at that wavelength), and the more the wavelength has a large absorption, the more the absorption spectrum can be moved. May not be possible.
[0083]
On the other hand, the type having a substituent on the central metal, that is, the so-called axial ligand type phthalocyanine or naphthalocyanine compound, on the other hand, does not require the recording / reproducing wavelength to increase the reflectance at the time of unrecording / erasing. In addition, it is possible to move the absorption spectrum so that the wavelength has a large absorption (a small change in the absorption spectrum is enough).
[0084]
This axial ligand acts to increase the distance between the dye molecules from a state in which the interaction between the dye molecules is extremely large, as in the unsubstituted state, and makes it possible to have absorption spectrum mobility. , Plays a role of not losing the interaction between dyes. In other words, by appropriately selecting the axial ligand, the aggregation state such as the distance between dye molecules and the angle of aggregation can be controlled by the cohesive force of the axial ligand and the spatial spread of the axial ligand. It is possible to provide a recording material with high contrast and good write-once.
[0085]
For this reason, it is an important point of the present invention that a compound having a substituent on the central metal, that is, a compound such as a so-called axial ligand type phthalocyanine or naphthalocyanine is selected as a material for an organic optical information recording medium. is there.
[0086]
In order to cause a large change in the absorption spectrum, first, the distance between the dye molecules, that is, between the π-conjugated systems of the dye basic skeleton, is such that the change in the absorption spectrum is sufficiently large due to the interaction between the substituents, such as the intermolecular force. It is necessary to draw in.
[0087]
In this case, even if the dye molecules are too close to each other, the mobility of the absorption spectrum may be lost, which is not preferable. However, compounds having a substituent on the central metal, ie, so-called axial ligand-type compounds such as phthalocyanine and naphthalocyanine, control the aggregation state such as the distance and angle at which the dye molecules can approach each other by the axial ligand. It can be convenient.
[0088]
As described above, the inventor of the present invention has found that the write-once can be controlled by controlling the length of the specific axis ligand and the spatial spread of the axis ligand.
[0089]
Incidentally, the absorption spectrum due to the interaction between the dyes can be approximated by incorporating the term of the dipole-dipole interaction into the Hamiltonian in a monomolecular state. That is, the dipole-dipole interaction is expressed by the following equation.
(Equation 1)

FIG. 4 is an explanatory diagram for explaining the position of the main skeleton and the amount of change in the absorption spectrum of compounds such as phthalocyanine and naphthalosinine.
[0090]
Now, considering only the term of dipole-dipole interaction and examining the energy change due to this interaction, the result is as shown in FIG. As is apparent from FIG. 5, the amount of change in the absorption spectrum depends on the position of the main skeleton in a compound such as phthalocyanine or naphthalocyanine in the θ or φ direction, or in a mixture of the θ and φ directions. It turns out that also changes.
[0091]
As can be seen from the equation of the dipole-dipole interaction, in order to increase the energy change due to this interaction, in FIG._A, Μ_BNeeds to be increased, the distance r must be reduced, or φ and θ need to be optimized.
[0092]
Dipole moment magnitude μ_A, Μ_BIn order to increase the value, it is necessary to change the main skeleton ring in a compound such as phthalocyanine or naphthalocyanine, so that molecular designing cannot be easily performed.
[0093]
Further, as described above, it is not preferable to make the distance r extremely small since the absorption spectrum mobility is lost.
[0094]
In the present invention, increasing the absorption spectrum shift by a change in the dipole-dipole interaction force, that is, a change in the interaction force between the dye basic skeleton π-conjugated system, is called a dye basic skeleton within a range that does not lose absorption spectrum mobility. This is performed by controlling the arrangement of the distances r, θ direction, and φ direction. That is, the inventor of the present invention has found that the above control can be performed by selecting a substituent of the central metal, that is, an axial ligand.
[0095]
Furthermore, the inventor of the present invention has found that by selecting an axial ligand, dyes can be aggregated with a certain degree of regularity by recording information. Recording of information in the present invention is performed by changing one stable aggregation state of a dye to another stable aggregation state.
[0096]
By changing the axis ligand, the inclination, steric hindrance, bulkiness, and flexibility of the axis ligand can be controlled, and therefore, the arrangement of the interaction between the dye molecules and the regularity of the aggregation state can be changed. .
[0097]
As such a ligand, an alkyl group is preferable. This is because the alkyl group has an appropriate cohesive force, and even if the alkyl group is enlarged, the interaction between the dye basic skeleton conjugated system can be provided.
[0098]
For example, the alkyl groups in the compounds R1, R2, and R3 represented by the following formulas (1) and (2) form a certain one as can be seen from the energy change due to the dipole-dipole interaction described above. In order to increase the amount of change in the absorption spectrum from the dye aggregation state, the other dye aggregation state is preferably aggregated with regularity. In order to achieve such a state, for example, an alkyl group in which the axial ligand is in a relatively upright state is selected, and the dye molecules take a so-called H-association state or the axial ligand is extremely It is preferable that an alkyl group which is in a sleeping state is selected and the dye molecules are in a state of so-called J-association, and there is an optimum combination for obtaining such a state.
[0099]
Embedded image

[0100]
Embedded image

[0101]
Where X¹~ X⁴Are each independently a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, an alkoxy group which may have a substituent, Aryloxy group, an alkylthio group which may have a substituent, an arylthio group which may have a substituent, a nitro group, a cyano group, a sulfonic acid group, a sulfonamide group, and a sulfonate group. k, l, m, and n are the substituents X¹~ X⁴And an integer of 0 to 4 is shown.
[0102]
As the two dye aggregation states, as a dye structure that easily forms a state close to the dispersion state of the dye and an aggregation state of the dye, for example, in the compounds represented by the formulas (1) and (2), R1, R2 , R3 are alkyl groups, and R1, R2, and R3 may be of different types of alkyl groups. As a preferred example, R3 has three carbon atoms more than the alkyl group having a larger number of carbon atoms among R1 and R2. In the alkyl group having the above difference or the compounds represented by the formulas (1) and (2), R1, R2, and R3 are alkyl groups, and R1, R2, and R3 are different even if the types of the alkyl groups are different. R1 and R2 are preferably alkyl groups having 3 or less carbon atoms, and R3 is an alkyl group having a difference of 3 or more carbon atoms among the alkyl groups having a larger number of carbon atoms among R1 and R2, which can increase the absorption spectrum change. It is a suitable combination.
[0103]
Alkyl groups suitable for the axial ligand include methyl, ethyl, n-propyl, n-butyl, isobutyl, n-pentyl, neopentyl, isoamyl, 2-methylbutyl, and n-hexyl. Group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group, 2-ethylbutyl group, n-heptyl group, 2-methylhexyl group, 3-methylhexyl group, 4-methylhexyl group, 5-methylhexyl Group, 2-ethylpentyl group, 3-ethylpentyl group, n-octyl group, 2-methylheptyl group, 3-methylheptyl group, 4-methylheptyl group, 5-methylheptyl group, 2-ethylhexyl group, 3- Primary alkyl groups such as ethylhexyl group, n-nonyl group, n-decyl group, n-dodecyl group, isopropyl group, sec-butyl group, 1-E Propyl group, 1-methylbutyl group, 1,2-dimethylpropyl group, 1-methylheptyl group, 1-ethylbutyl group, 1,3-dimethylbutyl group, 1,2-dimethylbutyl group, 1-ethyl-2-methyl Propyl, 1-methylhexyl, 1-ethylheptyl, 1-propylbutyl, 1-isopropyl-2-methylpropyl, 1-ethyl-2-methylbutyl, 1-propyl-2-methylpropyl, 1-methylheptyl group, 1-ethylhexyl group, 1-propylpentyl group, 1-isopropylpentyl group, 1-isopropyl-2-methylbutyl group, 1-isopropyl-3-methylbutyl group, 1-methyloctyl group, 1-ethyl Secondary alkyl groups such as propyl group, 1-propylhexyl group, 1-isobutyl-3-methylbutyl group, ter Tertiary alkyl groups such as -butyl group, tert-hexyl group, tert-amyl group and tert-octyl group, cyclohexyl group, 4-methylcyclohexyl group, 4-ethylcyclohexyl group, 4-tert-butylcyclohexyl group, 4- (2-ethylhexyl) cycloalkyl groups such as a cyclohexyl group, a bornyl group, an isobonyl group, and an adamantane group.
[0104]
Also, X in equations (1) and (2)¹~ X⁴Are each independently a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, an alkoxy group which may have a substituent, Aryloxy group, an alkylthio group which may have a substituent, an arylthio group which may have a substituent, a nitro group, a cyano group, a sulfonic acid group, a sulfonamide group, and a sulfonate group. k, l, m, and n are the substituents X¹~ X⁴And an integer of 0 to 4 is shown. X in equations (1) and (2)¹~ X⁴Preferably, the substituent is not so sterically large and the number of substituents is small. This is because the substituent is sterically large and the introduction of a large number of substituents causes the characteristics of the axial ligand type dye absorption spectrum to be lost.
[0105]
More specifically, in the compounds represented by the formulas (1) and (2), when R1, R2, and R3 are the same and are large alkyl groups, they are spatially dense and the pigment basic skeleton conjugated with each other. Is not so close (r shown in FIG. 4 becomes large), the interaction of the dye basic skeleton π-conjugated system is reduced, and the absorption spectrum shift amount is small.
[0106]
Further, if all three alkyl groups are large alkyl groups, the alkyl group portion tends to crystallize and cannot be used as an optical information recording medium.
[0107]
Therefore, in the compounds represented by the formulas (1) and (2), it is possible to improve the above problem by lengthening one alkyl group of R1, R2, and R3 and shortening the other two. it can. As a result, a recording material that causes a large change in absorption spectrum can be obtained.
[0108]
However, these changes in the dye absorption spectrum are changes that initially aggregate from a somewhat random state to enhance the interaction between dye molecules by recording, and the recorded state is not a state in which the dyes are regularly aggregated. . Therefore, the change in the absorption spectrum is a similar movement as shown in FIG. 6, and the polarity of the reflectance by recording is different (reverse) on the short wavelength side and the long wavelength side with respect to the peak wavelength of the absorption spectrum. For this reason, there is a possibility that information recorded at one certain recording wavelength cannot be reproduced at two or more different wavelengths because the recorded information has a reduced reflectance. Actually, in the case of the phthalocyanine compound represented by the formula (1), the wavelength regions around 780 nm and 630 nm respectively correspond to the long wavelength side and the short wavelength side with respect to the peak wavelength of the absorption spectrum in FIG. It corresponds to the vicinity of the base (of course, the absorption spectra are different from each other). Therefore, it is impossible to reproduce information recorded at both the wavelength of 760 nm to 830 nm and the wavelength of 620 to 650 nm as a decrease in reflectance. In order to solve this, it is not possible to simply increase the cohesion to an unrecorded state to some extent by recording information, or conversely, disperse it. There is.
[0109]
The inventor of the present invention has found that the phthalocyanine compound represented by the following formula (3) exhibits different properties from other similar dyes.
[0110]
Embedded image

[0111]
That is, according to the phthalocyanine compound represented by the formula (3), the dye aggregates regularly to some extent from the unrecorded state, and the regularity of the dye is further increased by the recording, resulting in a large change in the aggregation state.
[0112]
In order to improve film forming property, film uniformity, recording and reproduction characteristics, a polymer may be further added to the above dye.
[0113]
Specific preferred examples include a polymethacrylic acid ester represented by the following formula (4) and a polystyrene substituted product represented by the following formula (5). In the polymethacrylate, R is preferably an alkyl group having 3 or more carbon atoms which may have a branch. In the polystyrene-substituted product, it is preferred that at least one of the substituents Z1 to Z6 is substituted with an alkyl group which may have a branch having 3 or more carbon atoms. However, when one position of the substituent is Z6, an alkyl group having 1 or more carbon atoms which may have a branch is preferably substituted, and a plurality of substituents may be introduced.
[0114]
Embedded image

[0115]
Embedded image

[0116]
The definition of these polymers is to reduce the interaction between polymers by introducing an alkyl group into the side chain and by introducing a bulky substituent that causes steric hindrance to the side chain. It is necessary to increase the intermolecular force, that is, the interaction between the alkyl group of the formula (1) and the substituent of the dye molecule, specifically, the alkyl group portion substituted by the central metal.
[0117]
Another preferred polymer compound is a polymer compound represented by the formula (6).
[0118]
Embedded image

[0119]
(6) In the formula, R11 and R12 represent hydrogen or an alkyl group which may have a substituent. These may be the same, but both do not have hydrogen at the same time, and at least one is an alkyl group which may have a substituent. In the formula (6), X is S, O, Se or NR^ThirteenAnd R^ThirteenRepresents a hydrogen, an alkyl group or an aryl group. Of these, a polythiophene derivative in which X is a sulfur atom is preferable, and poly (3-alkylthiophene) in which one of R11 and R12 is a hydrogen atom and the other is an alkyl group is more preferable. Further, among poly (3-alkylthiophenes), an alkyl group having n = 6 or more is preferable from the viewpoints of solubility in an organic solvent, interaction force between polymers, interaction force with a dye molecule, and the like.
[0120]
(Recording layer)
In forming the recording layer, other dyes may be added in order to promote the change of the light energy efficiency, wavelength matching, molecular aggregation state, dispersion state, and crystal state of the dye. Examples of such dyes include polymethine dyes, naphthalocyanine-based, phthalocyanine-based, squarylium-based, coroconium-based, pyrylium-based, naphthoquinone-based, anthraquinone (indanthrene) -based, xanthene-based, triphenylmethane-based, azulene-based, and tetrahydrogen-based. Choline-based, phenanthrene-based, triphethiazine-based dyes, metal complex compounds, and the like. The above dyes may be used alone or in combination of two or more. Further, metals and metal compounds such as In, Te, Bi, Al, Be, and TeO are contained in the dye.₂, SnO, As, Cd, etc. can be used in the form of dispersion mixing or lamination. Furthermore, various materials such as ionomer resins, polyamide resins, vinyl resins, natural polymers, silicones, liquid rubbers, and the like, or silane coupling agents, etc., may be dispersed and used in the above dyes. It can be used together with a stabilizer (for example, a transition metal complex), a dispersant, a flame retardant, a lubricant, an antistatic agent, a surfactant, a plasticizer, etc. for the purpose of improving the properties or improving the properties.
[0121]
The formation of the recording layer can be performed by an ordinary method such as vapor deposition, sputtering, CVD, or solvent application. When the coating method is used, the dye or the like is dissolved in an organic solvent, and the coating is performed by a conventional coating method such as spraying, roller coating, dipping, and spin coating.
[0122]
Examples of the organic solvent include alcohols such as methanol, ethanol and isopropanol; ketones such as acetone, methyl ethyl ketone and cyclohexane; amides such as N, N-dimethylacetamide and N-N dimethylformamide; and sulfoxides such as dimethyl sulfoxide. , Ethers such as tetrahydrofuran, dioxane, diethyl ether, ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, aliphatic halogenated carbons such as chloroform, methylene chloride, dichloroethane, carbon tetrachloride, trichloroethane, or Aromatic compounds such as benzene, xylene, monochlorobenzene, dichlorobenzene, etc., cellsolves such as methoxyethanol and ethoxyethanol, hexane, pentane, cyclohexane, methyl Hydrocarbons such as cyclohexane or the like can be used.
[0123]
The thickness of the recording layer is 100 Å to 10 μm, preferably 200 to 2,000 Å.
[0124]
(substrate)
The substrate must be transparent to the laser beam used only when recording / reproducing is performed from the substrate side, and need not be transparent when performing recording / reproducing from the recording layer side.
[0125]
As the substrate material, for example, plastic such as polyester, acrylic resin, polyamide, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, polyimide, or glass, ceramic, metal or the like can be used.
[0126]
Note that a guide groove or guide pit for tracking and a preformat such as an address signal may be formed on the surface of the substrate.
[0127]
(Undercoat layer)
The undercoat layer is
(A) improvement in adhesiveness,
(B) water or gas barrier,
(C) improved storage stability of the recording layer,
(D) improvement in reflectance,
(E) protection of the substrate from solvents,
(F) Formation of guide grooves, guide pits, preformats, etc.
It is used for the purpose.
[0128]
For the purpose of (a), polymer materials, for example, various polymer materials such as ionomer resin, polyamide resin, vinyl resin, natural resin, natural polymer, silicone, liquid rubber, and silane coupling agent Can be used.
[0129]
For the purposes of (b) and (c), besides the above-mentioned polymer material, an inorganic compound such as SiO₂, MgF₂, SiO, TiO₂, ZnO, TiN, SiN and other metals or metalloids, for example, Zn, Cu, Ni, Cr, Ge, Se, Au, Ag, Al and the like.
[0130]
For the purpose of (d), for example, Al, Ag or the like, or an organic thin film having a metallic luster such as a methine dye or a xanthene dye can be used.
[0131]
For the purposes (e) and (f), an ultraviolet curable resin, a thermosetting resin, a thermoplastic resin, or the like can be used.
[0132]
The thickness of the undercoat layer is suitably 0.01 to 30 μm, preferably 0.05 to 10 μm.
[0133]
(Protective layer / substrate surface hard coat layer)
The protective layer or the hard coat layer on the substrate surface
(A) protection of the recording layer (reflection / absorption layer) from scratches, dust, dirt, etc.
(B) improvement in storage stability of the recording layer (reflection / absorption layer),
(C) Improvement of reflectance
It is used for the purpose.
[0134]
For the above purpose, the materials shown in the description of the undercoat layer can be used. Further, as the inorganic material, SiO, SiO₂And organic materials such as polymethyl acrylate, polycarbonate, epoxy resin, polystyrene, polyester resin, vinyl resin, cellulose, aliphatic hydrocarbon resin, aromatic hydrocarbon resin, natural rubber, styrene-butadiene resin, Thermosoftening and heat melting resins such as chloroprene rubber, wax, alkyd resin, drying oil, and rosin can also be used.
[0135]
Among the above materials, the most preferable substance for the protective layer or the hard coat layer on the substrate surface is an ultraviolet curable resin having excellent productivity. The thickness of the protective layer or the hard coat layer on the substrate surface is suitably 0.01 to 30 μm, preferably 0.05 to 10 μm.
[0136]
In the present invention, the undercoat layer, the protective layer, and the hard coat layer on the substrate surface include, as in the case of the recording layer, a stabilizer, a dispersant, a flame retardant, a lubricant, an antistatic agent, a surfactant, a plasticizer, and the like. Can be contained.
[0137]
(Metal reflective layer)
The reflective layer may be made of a metal, a semi-metal, or the like, which has a high reflectance by itself and is hardly corroded. Examples of the material include Au, Ag, Cu, Cr, Ni, and Al, and Au and Al are preferable. These metals and metalloids may be used alone or as two or more alloys.
[0138]
Examples of the method for forming the film of the reflective layer include vapor deposition and sputtering, and the film thickness is 50 to 3000 angstroms, preferably 100 to 1000 angstroms.
[0139]
Next, embodiments of the optical information recording medium of the present invention will be described.
[Example 1]
[0140]
In the phthalocyanine compound represented by the following formula (7), two compounds in which n is 7 and 11 were synthesized. This phthalocyanine compound was dissolved in chloroform, and a thin film was formed on a glass substrate by spin coating.
[0141]
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[0142]
8 and 9 show the results of measuring the spectral characteristics of these two compounds. FIG. 8 shows the case where n is 7, and FIG. 9 shows the case where n is 11. As is clear from FIGS. 8 and 9, it can be seen that this dye initially forms a plurality of stable aggregated states (unrecorded state).
[0143]
The absorption spectra of the chloroform solution of the two compounds are as shown in FIGS. 10 and 11, respectively. In both the solutions, there is almost no interaction between the dyes and the molecules are in a monodispersed state. it is conceivable that. This indicates that the dye of the formula (7) forms a unique aggregation state when it becomes a solid.
[0144]
Further, the absorption spectra of the dyes of n = 7 and 11 when heated at initial stages of 100 ° C., 150 ° C., 180 ° C., and 200 ° C. were measured. The results are shown in FIGS. FIG. 12 shows the result when n = 7, and FIG. 13 shows the result when n = 11. As shown in FIGS. 12 and 13, the absorption spectrum changes due to heating, and it can be seen that the aggregation state of the dye can be changed by heating.
[0145]
As a result of observing the state of the film of the dye by heating at 100 ° C., 150 ° C., 180 ° C., and 200 ° C. with a high-resolution microscope, the surface shape was uniform without any change. That is, it was found that the absorption spectrum did not change due to irregular reflection due to the change in the surface shape of the recording layer, but was caused by a pure change in the aggregation state.
[0146]
[Comparative example]
As a comparative example to Example 1 described above, phthalocyanine compounds represented by Formulas (8) to (15) were synthesized, dissolved in chloroform, and formed into a thin film on a glass substrate by spin coating.
[0147]
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[0148]
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[0149]
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[0150]
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[0151]
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[0152]
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[0153]
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[0154]
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[0155]
Similarly, the results of measuring the spectral characteristics of the compounds of these comparative examples are shown in FIGS. From FIG. 14 to FIG. 20, it is presumed that the dye molecules are randomly aggregated initially. This is because the initial absorption spectrum has one peak and the absorption spectrum width is narrow.
[0156]
FIG. 14 shows the SiPc [-OSi (CH) of the equation (8).₃)₂C₄H₉]₂And FIG. 15 shows that the SiPc [-OSi (CH₃)₂C₅H₁₁]₂And FIG. 16 shows the SiPc [-OSi (CH) of the equation (10).₃)₂C₆H_Thirteen], FIG. 17 shows the SiPc [-OSi (CH) of the formula (11).₃)₂C₈H₁₇]₂And FIG. 18 shows the SiPc [-OSi (CH₃)₂C₁₀H₂₁]₂And FIG. 19 shows that the SiPc [-OSi (CH₃)₂C₁₂H₂₅]₂20, FIG. 20 shows the SiPc [-OSi (C₂H₅)₂C₈H₁₇]₂2 shows the thin film absorption spectrum of the sample.
[0157]
The SiPc [-OSi (i-C₃H₇)₂C₈H₁₇]₂Although the thin film absorption spectrum of is not shown, the phase is separated from the initial stage (at the time of film formation), and the absorption spectrum change is represented by the SiPc [-OSi (C₂H₅)₂C₈H₁₇]₂Was similar to the change in absorption spectrum.
[0158]
In the dyes of these comparative examples, phase separation or crystallization of the dye occurred at the initial stage or by heating, and the film quality was poor. It is considered that this is also caused by a specific effect due to the cohesive force and spatial spread of the substituent.
[0159]
In the compounds of Comparative Examples, when heated at 100 ° C., 150 ° C., 180 ° C., and 200 ° C., the absorbance sharply decreased, and the absorption spectrum did not shift.
[0160]
From the above, the compounds of the examples shown in the formula (7) have a specific effect of forming one or more regular dye aggregation states depending on the dye structure, and the aggregation state is greatly changed by heating. It was found that the state could be changed to the aggregation state. In addition, the absorption spectrum changes in a plurality of wavelength ranges due to the change in the aggregation state due to the heating, and information can be recorded and reproduced with a laser beam having a wavelength selected from a plurality of different wavelength ranges. It has been found that information recorded at a certain wavelength can be reproduced at a plurality of different reproduction wavelengths.
[0161]
Further, the dye having the structure of the formula (7) is compatible between a CD-based medium and a DVD-based medium, that is, an optical information recording medium using near 780 nm as a recording / reproducing wavelength and an optical information recording medium using near 630 nm. It has been confirmed below whether or not the medium has a characteristic that can be used as a medium having the following.
[0162]
By spin coating, a thin film of the dye (n = 11 in FIG. 7) (see FIG. 9) was formed on a glass substrate, and a sample was formed by further depositing gold on the thin film.
[0163]
The reflectivity of the sample at this time is as shown by the solid line in FIG. 21. The reflectivity is about 79% at 780 nm and about 57% at 635 nm. I found it.
[0164]
Next, the reflectance when this sample is heated at 180 ° C. for 5 minutes is shown by a broken line in FIG. As is evident from the results, it was found that the reflectance decreased due to the heating recording at around 780 nm and around 650 nm. The change in reflectance due to heating recording was a change from 79% to 37% at 780 nm, and a change from 57% to 46% at 635 nm.
[0165]
As described above, the fact that both absorption spectra near 650 nm and around 780 nm could be changed by heating is that if a laser beam having a wavelength that any dye absorbs is applied, the absorption heating effect causes It can be seen that a change in reflectance similar to that in FIG. 21 is obtained. That is, whether recording is performed at a recording wavelength of 760 nm to 830 nm or at a recording wavelength of 620 to 650, both absorption spectra in the vicinity of 760 nm to 830 nm and near 620 nm to 650 nm can be changed simultaneously. In addition, information recorded at an arbitrary recording wavelength selected from 760 nm to 830 nm or 620 nm to 650 nm is obtained by recording information recorded at a reproduction wavelength of 760 nm to 830 nm or at a reproduction wavelength of 620 nm to 650 nm with respect to an unrecorded state. , It was revealed that the information can be reproduced as information with a reduced reflectance.
[0166]
【The invention's effect】
As described above, according to the optical information recording medium of the present invention (claim 1),The dye has the general formula
Embedded image

Since the phthalocyanine compound is represented by the following formula, a large spectral shift can be obtained, and information can be recorded and reproduced with laser light having a wavelength selected from a plurality of different wavelength ranges. Therefore, information can be shared among a plurality of optical information recording media and between a plurality of optical information recording medium drives, and the resources of the constantly changing and overflowing optical information recording medium can be shared. A highly compatible optical information recording medium can be obtained,Since the aggregation state of the dye changes due to the addition of external energy, and the absorption spectrum changes for a plurality of different wavelength ranges, recording and reproduction of information using laser light of a wavelength selected from a plurality of different wavelength ranges is performed. It can be carried out. Further, since only the aggregation state of the dye is changed, a low-power laser beam can be used for recording and reproducing information. Therefore, information can be shared among a plurality of optical information recording media and between a plurality of optical information recording medium drives, and the resources of the constantly changing and overflowing optical information recording medium can be shared. An optical information recording medium with high compatibility can be obtained.
[0167]
Further, according to the optical information recording medium of the present invention (claim 2), in the optical information recording medium of claim 1, the recording layer is formed by the change of the aggregation state of the dye before the change of the aggregation state of the dye. Since information is recorded by lowering the reflectivity for all light selected from a plurality of different wavelength ranges as compared with the reflectivity, laser light of a wavelength selected from a plurality of different wavelength ranges is used. Recording and reproduction of information can be performed. Further, since only the aggregation state of the dye is changed, a low-power laser beam can be used for recording and reproducing information. Therefore, information can be shared among a plurality of optical information recording media and between a plurality of optical information recording medium drives, and the resources of the constantly changing and overflowing optical information recording medium can be shared. An optical information recording medium with high compatibility can be obtained.
[0168]
According to the optical information recording medium of the present invention (claim 3), the plurality of different wavelength ranges are 620 to 650 nm and 760 to 830 nm in the optical information recording medium of claim 1 or 2. Recording and reproduction of information can be performed with laser light having a wavelength selected from a plurality of different wavelength ranges. Therefore, information can be shared among a plurality of optical information recording media and between a plurality of optical information recording medium drives, and the resources of the constantly changing and overflowing optical information recording medium can be shared. An optical information recording medium with high compatibility can be obtained.
[0169]
According to the optical information recording medium of the present invention, the information is recorded and reproduced with a laser beam having a wavelength selected from a wavelength range of 620 to 650 nm. And information can be recorded and reproduced with a laser beam having a wavelength selected from a wavelength range of 760 to 830 nm, so that a plurality of optical information recording media and a plurality of optical information recording medium drives can be used. The information can be shared, and the resources of the constantly changing and overflowing optical information recording medium can be shared, and a highly compatible optical information recording medium can be obtained.
[0170]
Further, according to the optical information recording medium of the present invention (claim 5), in the optical information recording medium of claim 4, the wavelength is further selected from any one of 620 to 650 nm or 760 to 830 nm. Since the information recorded by the laser light of the wavelength can be reproduced by the laser light of all the wavelengths selected from the wavelength range of 620 to 650 nm and 760 to 830 nm, a plurality of optical information recording media, a plurality of optical information It is possible to share information between recording medium drives, to share resources of an optical information recording medium that is constantly changing and overflowing, and to obtain a highly compatible optical information recording medium.
[0172]
Further, an information recording method for an optical information recording medium according to the present invention (claim6According to the claim)1-5The external energy is added to the recording layer of the optical information recording medium described in any one of the above to change the aggregation state of the dye, and the absorption spectrum in a plurality of different wavelength ranges differs from the absorption spectrum before the external energy is added. Since information is recorded on the recording layer by changing to an absorption spectrum, information can be recorded with laser light having a wavelength selected from a plurality of different wavelength ranges. Further, since only the aggregation state of the dye is changed, a low-power laser beam can be used for recording and reproducing information. Therefore, information can be shared among a plurality of optical information recording media and between a plurality of optical information recording medium drives, and the resources of the constantly changing and overflowing optical information recording medium can be shared. An information recording method for an optical information recording medium with high compatibility can be obtained.
[0173]
Further, an information recording method for an optical information recording medium according to the present invention (claim7According to the claim)6In the information recording method for an optical information recording medium described above, information is recorded on a recording layer by reducing the reflectance for light of all wavelengths selected from a plurality of different wavelength ranges from the reflectance before the absorption spectrum change. Therefore, information can be recorded with laser light having a wavelength selected from a plurality of different wavelength ranges. Further, since only the aggregation state of the dye is changed, a low-power laser beam can be used for recording and reproducing information. Therefore, information can be shared among a plurality of optical information recording media and between a plurality of optical information recording medium drives, and the resources of the constantly changing and overflowing optical information recording medium can be shared. An information recording method for an optical information recording medium with high compatibility can be obtained.
[0174]
Further, an information recording method for an optical information recording medium according to the present invention (claim8According to the claim)6 or 7In the information recording method for an optical information recording medium described above, since the plurality of different wavelength ranges are 620 to 650 nm and 760 to 830 nm, information can be transferred between a plurality of optical information recording media and a plurality of optical information recording medium drives. In addition to sharing, it is possible to share the resources of the optical information recording medium that constantly changes and floods, and it is possible to obtain a highly compatible information recording method for the optical information recording medium.
[0175]
Further, an information reproducing method for an optical information recording medium according to the present invention (claim9According to the claim)1-5Reproducing the information recorded on the recording layer by using light of a wavelength selected from a plurality of different wavelength ranges in which the absorption spectrum changes by adding external energy. Therefore, information can be reproduced with laser light having a wavelength selected from a plurality of different wavelength ranges. Therefore, information can be shared among a plurality of optical information recording media and between a plurality of optical information recording medium drives, and the resources of the constantly changing and overflowing optical information recording medium can be shared. An information reproducing method for an optical information recording medium with high compatibility can be obtained.
[0176]
Further, an information reproducing method for an optical information recording medium according to the present invention (claim10According to the claim)9In the information reproducing method for an optical information recording medium described above, the recording layer is irradiated with light having a wavelength selected from a plurality of different wavelength ranges, the reflected light is received, and the reflection in a state where information is not recorded on the recording layer is obtained. Since the information recorded on the recording layer is reproduced by detecting a decrease in the reflectance with respect to the reflectance, the information can be reproduced with laser light having a wavelength selected from a plurality of different wavelength ranges. Therefore, information can be shared between a plurality of optical information recording media and between a plurality of optical information recording medium drives, and the resources of the constantly changing and overflowing optical information recording medium can be shared. An information reproducing method for an optical information recording medium with high compatibility can be obtained.
[0177]
Further, an information reproducing method for an optical information recording medium according to the present invention (claim11According to the claim)9 or 10In the information reproducing method for an optical information recording medium described above, since the plurality of different wavelength ranges are 620 to 650 nm and 760 to 830 nm, information can be transferred between a plurality of optical information recording media and a plurality of optical information recording medium drives. It is possible to share the resources of the optical information recording medium, which constantly changes and overflows, and to obtain a highly compatible information reproducing method for the optical information recording medium.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram for explaining a shift of an absorption spectrum of a dye used for a recording layer.
FIG. 2 is an explanatory diagram for explaining a shift of an absorption spectrum of a dye used for a recording layer.
FIG. 3 is an explanatory diagram for explaining a shift of an absorption spectrum of a dye used for a recording layer.
FIG. 4 is an explanatory diagram for explaining a position of a main skeleton of a compound such as phthalocyanine and naphthalothinine and a change amount of an absorption spectrum.
FIG. 5 is an explanatory diagram for explaining an energy change depending on a position of a main skeleton of a compound such as phthalocyanine and naphthalothinine.
FIG. 6 is an explanatory diagram for explaining a shift of an absorption spectrum of a dye used for a recording layer.
FIG. 7 is an explanatory diagram for explaining a shift of an absorption spectrum of a dye used for a recording layer.
FIG. 8 is an explanatory diagram illustrating spectral characteristics of an example (formula (7), n = 7) of a dye compound used for an optical information recording medium according to the present invention.
FIG. 9 is an explanatory diagram illustrating spectral characteristics of an example (formula (7), n = 11) of a dye compound used for an optical information recording medium according to the present invention.
FIG. 10 is an explanatory diagram illustrating an absorption spectrum when an example of the dye compound (formula (7), n = 7) used in the optical information recording medium according to the present invention is dissolved in a chloroform solution.
FIG. 11 is an explanatory diagram illustrating an absorption spectrum when an example of the dye compound (formula (7), n = 11) used in the optical information recording medium according to the present invention is dissolved in a chloroform solution.
FIG. 12 shows an example of a dye compound (formula (7), n = 7) used in the optical information recording medium according to the present invention, which was formed into a thin film from a chloroform solution by a spin coating method. It is explanatory drawing explaining the absorption spectrum at the time of heating to 180 degreeC and 200 degreeC.
FIG. 13 shows an example of a dye compound (formula (7), n = 11) used in an optical information recording medium according to the present invention, which is formed into a thin film from a chloroform solution by a spin coating method, and is initially in a state of 100 ° C., 150 ° C., It is explanatory drawing explaining the absorption spectrum at the time of heating to 180 degreeC and 200 degreeC.
FIG. 14 shows a comparative example (formula (8)) of a dye compound used for an optical information recording medium, formed into a thin film from a chloroform solution by a spin coating method, and heated to an initial state, 100 ° C., 150 ° C., 180 ° C., and 200 ° C. FIG. 4 is an explanatory diagram illustrating an absorption spectrum at that time.
FIG. 15 shows a comparative example (formula (9)) of a dye compound used for an optical information recording medium, formed into a thin film from a chloroform solution by a spin coating method, and heated to an initial state, 100 ° C., 150 ° C., 180 ° C., and 200 ° C. FIG. 4 is an explanatory diagram illustrating an absorption spectrum at that time.
FIG. 16 shows a comparative example (formula (10)) of a dye compound used for an optical information recording medium, formed into a thin film from a chloroform solution by a spin coating method, and heated to an initial state, 100 ° C., 150 ° C., 180 ° C., and 200 ° C. FIG. 4 is an explanatory diagram illustrating an absorption spectrum at that time.
FIG. 17 shows a comparative example (formula (11)) of a dye compound used for an optical information recording medium, formed into a thin film from a chloroform solution by a spin coating method, and heated to an initial state, 100 ° C., 150 ° C., 180 ° C., and 200 ° C. FIG. 4 is an explanatory diagram illustrating an absorption spectrum at that time.
FIG. 18 shows a comparative example (formula (12)) of a dye compound used for an optical information recording medium, formed into a thin film from a chloroform solution by a spin coating method, and heated to an initial state, 100 ° C., 150 ° C., 180 ° C., and 200 ° C. FIG. 4 is an explanatory diagram illustrating an absorption spectrum at that time.
FIG. 19 shows a comparative example (formula (13)) of a dye compound used for an optical information recording medium, formed into a thin film from a chloroform solution by a spin coating method, and heated to an initial state, 100 ° C., 150 ° C., 180 ° C., and 200 ° C. FIG. 4 is an explanatory diagram illustrating an absorption spectrum at that time.
FIG. 20 shows a comparative example (formula (14)) of a dye compound used for an optical information recording medium, formed into a thin film from a chloroform solution by a spin coating method, and heated to an initial state, 100 ° C., 150 ° C., 180 ° C., and 200 ° C. FIG. 4 is an explanatory diagram illustrating an absorption spectrum at that time.
FIG. 21 is an explanatory diagram for explaining a change in reflectance when an embodiment (formula (7), n = 11) of a dye compound used for an optical information recording medium according to the present invention is used.
FIG. 22 is an explanatory diagram for explaining a state where information is written to a CD-R.
[Explanation of symbols]
1 substrate
2 Recording layer
3 Gold reflective surface

Claims (11)

An optical information recording medium constituted by laminating a recording layer containing at least a dye and a reflective layer on a substrate,
The dye has a general formula

(However, X ^{1 to} X ⁴ each independently represent a hydrogen atom, a halogen atom, an alkyl group optionally having a substituent, an aryl group optionally having a substituent, an alkoxy group optionally having a substituent. Group, aryloxy group which may have a substituent, alkylthio group which may have a substituent, arylthio group which may have a substituent, nitro group, cyano group, sulfonic group, sulfonic amide group , A sulfonic acid ester group, and o, p, q, and r are each an integer of 0 to ^{4 in} the number of substituents X ^{1 to} X ⁴ ).
An optical information recording medium, wherein the dye changes its aggregation state by the addition of external energy and changes its absorption spectrum in a plurality of different wavelength ranges. 2. The optical information recording medium according to claim 1, wherein the recording layer is selected from the plurality of different wavelength ranges due to a change in the aggregation state of the dye, as compared with a reflectance before the change in the aggregation state of the dye. An optical information recording medium for recording and reproducing information by lowering the reflectance for all light. 3. The optical information recording medium according to claim 1, wherein the plurality of different wavelength ranges are 620-650 nm and 760-830 nm. 4. The optical information recording medium according to claim 3, wherein information can be recorded and reproduced with a laser beam having a wavelength selected from the wavelength range from 620 to 650 nm, and a wavelength selected from the wavelength range from 760 to 830 nm. An optical information recording medium characterized in that information can be recorded and reproduced with the laser light. 5. The optical information recording medium according to claim 4, further comprising: information recorded by a laser beam having a wavelength selected from any one of the wavelength ranges of 620 to 650 nm or 760 to 830 nm. An optical information recording medium which can be reproduced with laser light of all wavelengths selected from a wavelength range of 760 to 830 nm. An information recording method for an optical information recording medium according to any one of claims 1 to 5 ,
Adding external energy to the recording layer to change the aggregation state of the dye,
An information recording method for an optical information recording medium, characterized in that information is recorded on the recording layer by changing the absorption spectra of the plurality of different wavelength ranges from the absorption spectrum before the external energy is applied to a different absorption spectrum. 7. The information recording method for an optical information recording medium according to claim 6 , wherein said recording is performed by lowering a reflectance for light of all wavelengths selected from said plurality of different wavelength ranges from a reflectance before said absorption spectrum change. An information recording method for an optical information recording medium, comprising recording information on a layer. 8. The information recording method for an optical information recording medium according to claim 6 , wherein said plurality of different wavelength ranges are 620-650 nm and 760-830 nm. An information reproducing method for an optical information recording medium according to any one of claims 1 to 5 ,
An optical information recording medium for reproducing information recorded on the recording layer by using light having a wavelength selected from the plurality of different wavelength ranges in which an absorption spectrum is changed by adding the external energy. Information reproduction method. 10. The information reproducing method for an optical information recording medium according to claim 9 , wherein the recording layer is irradiated with light having a wavelength selected from the plurality of different wavelength ranges, the reflected light is received, and the information is recorded on the recording layer. An information reproducing method for an optical information recording medium, comprising: reproducing information recorded on the recording layer by detecting a decrease in reflectance with respect to a reflectance in a state where the information is not recorded. 11. The information reproducing method for an optical information recording medium according to claim 9 , wherein the plurality of different wavelength ranges are 620 to 650 nm and 760 to 830 nm.

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