JP2003263778A - Multi-valued worm (write-once-read-many) type optical recording medium and method of multi-valued recording - Google Patents
Multi-valued worm (write-once-read-many) type optical recording medium and method of multi-valued recordingInfo
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- JP2003263778A JP2003263778A JP2002066570A JP2002066570A JP2003263778A JP 2003263778 A JP2003263778 A JP 2003263778A JP 2002066570 A JP2002066570 A JP 2002066570A JP 2002066570 A JP2002066570 A JP 2002066570A JP 2003263778 A JP2003263778 A JP 2003263778A
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Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、記録データに応じ
記録マーク長や振幅に加えて記録極性も変化させること
により多値記録を行うことができる追記型光記録媒体、
その記録原理、及び多値記録方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a write-once type optical recording medium capable of performing multi-valued recording by changing recording polarity in addition to recording mark length and amplitude according to recording data.
The recording principle and the multilevel recording method are related.
【0002】[0002]
【従来の技術】近年、光記録媒体は更なる大容量化、高
密度化が要求されている。光記録媒体の大容量化、高密
度化を実現するための一方法として、多値記録がある。
多値記録は、情報を3通り以上の値に対応付けて記録再
生を行うことを意味し、「0」又は「1」の2値に対応
させて記録再生を行う2値記録と区別するための概念で
ある。多値記録の詳細については、例えば特開平6−7
6399号公報に記載されている。この従来例は、マー
クエッジ方式の記録再生方法において、記録マークのエ
ッジの位置を記録データに対応させて基準位置から段階
的にシフトさせることより、多値情報を記録する。この
マークエッジ方式の多値記録では、エッジ位置のシフト
数(段数)が多いほど多値化即ち高密度化に有利であ
る。しかしながら、限られた基準クロックの周期に対し
てエッジ位置のシフト数を増やそうとすれば、エッジの
形成を精密に制御する必要がある。一方、レーザ光の照
射によって形成される記録マークのエッジ位置を制御す
ることは容易ではない。2. Description of the Related Art In recent years, optical recording media have been required to have larger capacities and higher densities. There is multi-valued recording as one method for realizing large capacity and high density of an optical recording medium.
Multi-valued recording means that information is recorded / reproduced by associating information with three or more values, and is distinguished from binary recording in which recording / reproduction is performed in correspondence with a binary value of “0” or “1”. Is the concept of. For details of multi-valued recording, see, for example, JP-A-6-7.
It is described in Japanese Patent No. 6399. In this conventional example, in a mark edge type recording / reproducing method, multi-valued information is recorded by shifting the position of the edge of the recording mark from the reference position in stages corresponding to the recording data. In the multi-valued recording of the mark edge method, the larger the number of shifts (the number of steps) of the edge position, the more advantageous the multi-valued recording, namely the higher recording density. However, in order to increase the number of shifts of the edge position with respect to the limited period of the reference clock, it is necessary to precisely control the formation of the edge. On the other hand, it is not easy to control the edge position of the recording mark formed by the irradiation of laser light.
【0003】別の従来例として、特開平8−28746
8号公報に記載されている光記録再生方法は、上記の従
来例のようなマークエッジ方式ではなく、ピットポジシ
ョン方式での多値記録を実現している。この場合、記録
マークの中心位置を基準クロックのエッジに対して段階
的にシフトさせて多値記録を行う。更に他の多値記録技
術としては、以下のようなものが挙げられる。即ち、C
Dと同じ再生専用型の光ディスクにおいて、記録データ
に対応したピットのエッジを8段階にシフトするという
SCIPERという多値記録技術が、例えば「S. K
obayashi,J.P.de Kock,T.Ho
rigome,H.Yamatsu and H.Oo
ki,Tech.Dig.ofOptical Dat
a Storage Conference,p.13
0(1994)」に記載されている。この技術では、従
来のディスク構造がそのまま使えるというメリットはあ
るが、信号処理回路が非常に複雑化するという問題があ
る。As another conventional example, Japanese Patent Laid-Open No. 8-28746.
The optical recording / reproducing method described in Japanese Patent Publication No. 8 realizes multi-value recording by a pit position method instead of the mark edge method as in the above-mentioned conventional example. In this case, the central position of the recording mark is shifted stepwise with respect to the edge of the reference clock to perform multilevel recording. Still another multilevel recording technique includes the following. That is, C
In the same read-only type optical disc as the D, a multi-valued recording technology called SCIPER that shifts the edge of the pit corresponding to the recorded data in 8 steps is described in "SK
obaashi, J .; P. de Kock, T .; Ho
Rigome, H .; Yamatsu and H.M. Oo
ki, Tech. Dig. of Optical Dat
a Storage Conference, p. Thirteen
0 (1994) ". This technique has an advantage that the conventional disk structure can be used as it is, but has a problem that the signal processing circuit becomes very complicated.
【0004】また、ピットの深さを段階的に変化させた
8レベルの多値記録技術が、例えば「S.Spielm
an,B.V.Johnson,G.A.McDerm
ott,M.P.O’Neil,C.Pietrzy
k,T.Shafaat,D.K.Warland a
nd T.L.Wong,Proc.SPIE,310
9,p.98(1997)」に記載されている。この技
術では、信号処理回路の複雑化はある程度抑えることが
できるが、ディスクの製造が困難となる。また、光磁気
ディスクにおいて、複数の磁性体記録膜を導入し、記録
用磁界の強度を切替えることによって各層の磁化反転を
選択的に起させる4値記録技術が、例えば「N.Sai
to,R.Sato,N.Kawamura and
M.Kajiura,Jpn.J.Appl.Phy
s.,28,p.343(1989)」に記載されてい
る。Further, an 8-level multilevel recording technique in which the pit depth is changed stepwise is described in, for example, "S. Spielm".
an, B. V. Johnson, G.M. A. McDerm
Ott, M .; P. O'Neil, C.I. Pietrzy
k, T. Shafaat, D.M. K. Warland a
nd T.N. L. Wong, Proc. SPIE, 310
9, p. 98 (1997) ". With this technique, the complexity of the signal processing circuit can be suppressed to some extent, but it is difficult to manufacture the disk. Further, in a magneto-optical disk, a four-valued recording technique that introduces a plurality of magnetic recording films and selectively causes the magnetization reversal of each layer by switching the strength of a recording magnetic field is disclosed in, for example, "N. Sai.
to, R.M. Sato, N .; Kawamura and
M. Kajiura, Jpn. J. Appl. Phy
s. 28, p. 343 (1989) ".
【0005】また、光磁気ディスクにおいて、記録用の
高周波磁界の周期を変えることによって、磁化反転間隔
を段階的に変化させた4値記録技術が、例えば「M.A
rai and S.Kobayashi,Tech.
Dig.of JointMORIS/ISOM,p.
32(1997)」に記載されている。また、相変化型
の光ディスクにおいて、記録レーザ光の強度変調によっ
て記録マークの大きさを制御した多値記録技術が、例え
ば「T.Ohta,K.Nishiuchi,K.Na
rumi,Y.Kitaoka,H.Ishibash
i,N.Yamada and T.Kozaki,J
pn.J.Appl.Phys.,39,p.770
(2000)」に記載されている。また、相変化型の光
ディスクにおいて、専用の相変化記録材料を用い記録パ
ルス波形を工夫して記録マーク長の制御を行うことによ
り、8値記録を行う多値記録技術が、例えば「M.P.
O’Neil and T.L.Wong,Tech.
Dig.of Optical Data Stora
ge Conference,p.170(200
0)」に記載されている。Further, in a magneto-optical disk, a four-valued recording technique in which the magnetization reversal interval is changed stepwise by changing the period of a high-frequency magnetic field for recording is disclosed in, for example, "M.A.
rai and S. Kobayashi, Tech.
Dig. of Joint MORIS / ISOM, p.
32 (1997) ". Further, in a phase change type optical disc, a multi-valued recording technique in which the size of a recording mark is controlled by modulating the intensity of a recording laser beam is disclosed in, for example, “T. Ohta, K. Nishiuchi, K. Na.
rumi, Y. Kitaoka, H .; Ishibash
i, N. Yamada and T.M. Kozaki, J
pn. J. Appl. Phys. 39, p. 770
(2000) ”. Further, in a phase change type optical disc, a multilevel recording technique for performing 8-value recording by controlling a recording mark length by devising a recording pulse waveform using a dedicated phase change recording material is disclosed in, for example, "MP .
O'Neil and T.M. L. Wong, Tech.
Dig. of Optical Data Storage
ge Conference, p. 170 (200
0) ”.
【0006】[0006]
【発明が解決しようとする課題】高密度化を図るために
は多値レベルの数を増やす必要があるが、多値レベルの
数を増やすと多値レベルの判定がより困難になるので、
再生信頼性が大幅に低下するという問題がある。また、
従来、再生専用型光記録媒体、光磁気記録媒体、又は相
変化型光記録媒体に適用できる多値記録技術は提案され
ているものの、有機材料を用いた追記型光記録媒体に有
効な多値記録技術は殆んど提案されていない。そこで、
本発明は、上記のような従来の問題を解決し、有機材料
を用いた追記型光記録媒体に有効な多値記録技術、多値
レベルの数を増やしながらも精度の高い多値記録が可能
で、350〜500nm程度の青色レーザ領域にも適用
可能な追記型光記録媒体、その記録原理、及び多値記録
方法の提供を目的とする。To increase the density, it is necessary to increase the number of multi-valued levels, but if the number of multi-valued levels is increased, it becomes more difficult to judge the multi-valued level.
There is a problem that the reproduction reliability is significantly reduced. Also,
Conventionally, although a multi-valued recording technology applicable to a read-only optical recording medium, a magneto-optical recording medium, or a phase-change optical recording medium has been proposed, a multi-valued recording technique using an organic material is effective for a multi-valued optical recording medium. Little recording technology has been proposed. Therefore,
INDUSTRIAL APPLICABILITY The present invention solves the above-mentioned conventional problems, and is a multi-value recording technique effective for a write-once type optical recording medium using an organic material, and it is possible to perform multi-value recording with high accuracy while increasing the number of multi-value levels. It is an object of the present invention to provide a write-once type optical recording medium applicable to a blue laser region of about 350 to 500 nm, its recording principle, and a multilevel recording method.
【0007】[0007]
【課題を解決するための手段】上記課題は、次の1)〜
11)の発明によって解決される。
1) 基板上に、下引層を介して、未記録時に記録再生
波長の光に対して吸収機能を有しない有機材料層を、該
有機材料層との屈折率差が大きい下引層と上引層とで挟
み込む層構造を有し、下引層又は上引層が光吸収機能を
有する光記録媒体であって、記録の際に変形方向と変形
界面の位置(種類)を変えることができ、これにより記
録マーク長や振幅の違いに加えて記録極性も異なる再生
信号が得られることを特徴とする多値記録可能な追記型
光記録媒体。
2) 基板上に、下引層を介して、未記録時に記録再生
波長の光に対して吸収機能を有しない有機材料層を、該
有機材料層との屈折率差が大きい下引層と上引層とで挟
み込む層構造を有し、下引層又は上引層が光吸収機能を
有する光記録媒体であって、有機材料層中の有機材料の
状態変化に伴う有機材料層から下引層への圧力、又は有
機材料層から上引層への圧力による記録マーク形成の記
録原理と、下引層や上引層の応力緩和、又は基板の熱膨
張による記録マーク形成の記録原理によって、記録の際
に記録マーク部の変形方向と変形界面の位置(種類)を
変えることができ、これにより記録マーク長や振幅の違
いに加えて記録極性も異なる再生信号が得られることを
特徴とする多値記録可能な追記型光記録媒体。
3) 基板上に、下引層を介して、未記録時の主吸収帯
が記録再生波長に対して長波長側に存在し、かつ未記録
時に記録再生波長の光に対して吸収機能を有しない有機
材料層を、該有機材料層との屈折率差が大きい下引層と
上引層とで挟み込む層構造を有し、下引層又は上引層が
光吸収機能を有する光記録媒体であって、記録の際に変
形方向と変形界面の位置(種類)を変えることができ、
これにより記録マーク長や振幅の違いに加えて記録極性
も異なる再生信号が得られることを特徴とする多値記録
可能な追記型光記録媒体。
4) 基板上に、下引層を介して、未記録時の主吸収帯
が記録再生波長に対して長波長側に存在し、かつ未記録
時に記録再生波長の光に対して吸収機能を有しない有機
材料層を、該有機材料層との屈折率差が大きい下引層と
上引層とで挟み込む層構造を有し、下引層又は上引層が
光吸収機能を有する光記録媒体であって、有機材料層中
の有機材料の状態変化に伴う有機材料層から下引層への
圧力、又は有機材料層から上引層への圧力による記録マ
ーク形成の記録原理と、下引層や上引層の応力緩和、又
は基板の熱膨張による記録マーク形成の記録原理によっ
て、記録の際に記録マーク部の変形方向と変形界面の位
置(種類)を変えることができ、これにより記録マーク
長や振幅の違いに加えて記録極性も異なる再生信号が得
られることを特徴とする多値記録可能な追記型光記録媒
体。
5) 記録再生波長が350〜500nmであることを
特徴とする1)〜4)の何れかに記載の多値記録可能な
追記型光記録媒体。
6) 有機材料層と上引層の界面形状が、基板の溝形状
と同一となるように形成されていることを特徴とする
1)〜5)の何れかに記載の多値記録可能な追記型光記
録媒体。
7) 基板上に、下引層を介して、未記録時に記録再生
波長の光に対して吸収機能を有しない有機材料層を、該
有機材料層との屈折率差が大きい下引層と上引層とで挟
み込む層構造を有し、下引層又は上引層が光吸収機能を
有する多値記録可能な追記型光記録媒体に対し、記録の
際に変形方向と変形界面の位置(種類)を変えることに
より、記録マーク長や振幅の違いに加えて記録極性も異
なる再生信号が得られるようにすることを特徴とする多
値記録方法。
8) 基板上に、下引層を介して、未記録時に記録再生
波長の光に対して吸収機能を有しない有機材料層を、該
有機材料層との屈折率差が大きい下引層と上引層とで挟
み込む層構造を有し、下引層又は上引層が光吸収機能を
有する多値記録可能な追記型光記録媒体に対し、有機材
料層中の有機材料の状態変化に伴う有機材料層から下引
層への圧力、又は有機材料層から上引層への圧力による
記録マーク形成の記録原理と、下引層や上引層の応力緩
和、又は基板の熱膨張による記録マーク形成の記録原理
によって、記録の際に記録マーク部の変形方向と変形界
面の位置(種類)を変え、これにより記録マーク長や振
幅の違いに加えて記録極性も異なる再生信号が得られる
ようにすることを特徴とする多値記録方法。
9) 基板上に、下引層を介して、未記録時の主吸収帯
が記録再生波長に対して長波長側に存在し、かつ未記録
時に記録再生波長の光に対して吸収機能を有しない有機
材料層を、該有機材料層との屈折率差が大きい下引層と
上引層とで挟み込む層構造を有し、下引層又は上引層が
光吸収機能を有する多値記録可能な追記型光記録媒体に
対し、記録の際に変形方向と変形界面の位置(種類)を
変えることにより、記録マーク長や振幅の違いに加えて
記録極性も異なる再生信号が得られるようにすることを
特徴とする多値記録方法。
10) 基板上に、下引層を介して、未記録時の主吸収
帯が記録再生波長に対して長波長側に存在し、かつ未記
録時に記録再生波長の光に対して吸収機能を有しない有
機材料層を、該有機材料層との屈折率差が大きい下引層
と上引層とで挟み込む層構造を有し、下引層又は上引層
が光吸収機能を有する多値記録可能な追記型光記録媒体
に対し、有機材料層中の有機材料の状態変化に伴う有機
材料層から下引層への圧力、又は有機材料層から上引層
への圧力による記録マーク形成の記録原理と、下引層や
上引層の応力緩和、又は基板の熱膨張による記録マーク
形成の記録原理によって、記録の際に記録マーク部の変
形方向と変形界面の位置(種類)を変え、これにより記
録マーク長や振幅の違いに加えて記録極性の異なる再生
信号が得られるようにすることを特徴とする多値記録方
法。
11) 記録再生波長が350〜500nmであること
を特徴とする7)〜10)の何れかに記載の多値記録方
法。[Means for Solving the Problems] The above problems are solved in the following 1) to
It is solved by the invention of 11). 1) An organic material layer which does not have a function of absorbing light of a recording / reproducing wavelength when not recorded is formed on a substrate through an undercoat layer and an undercoat layer having a large refractive index difference from the organic material layer. An optical recording medium having a layer structure sandwiched between an undercoating layer and an undercoating layer, and the undercoating layer or the overcoating layer having a light absorbing function, and the deformation direction and the position (type) of the deformation interface can be changed during recording. Thus, a write-once type optical recording medium capable of multi-value recording, wherein a reproduction signal having a different recording polarity in addition to a difference in recording mark length and amplitude is obtained. 2) On the substrate, an organic material layer having no absorption function for light having a recording / reproducing wavelength at the time of non-recording is placed over the undercoat layer and an undercoat layer having a large refractive index difference from the organic material layer. An optical recording medium having a layer structure sandwiched between an organic material layer and an undercoating layer, wherein the undercoating layer or the overcoating layer has a light absorbing function, Recording by the recording principle of recording mark formation by pressure to the organic material layer or pressure from the organic material layer and recording principle of recording mark formation by stress relaxation of the undercoating layer or the overcoating layer or thermal expansion of the substrate. In this case, it is possible to change the deformation direction of the recording mark portion and the position (type) of the deformation interface, and this makes it possible to obtain a reproduction signal having different recording polarities in addition to the difference in recording mark length and amplitude. A write-once type optical recording medium capable of recording values. 3) The main absorption band at the time of unrecording exists on the long wavelength side with respect to the recording / reproducing wavelength through the undercoat layer on the substrate, and has the absorption function for the light of the recording / reproducing wavelength at the time of unrecording. An optical recording medium having a layer structure in which an organic material layer not sandwiched is sandwiched between an undercoating layer and an overcoating layer having a large refractive index difference with the organic material layer, and the undercoating layer or the overcoating layer has a light absorbing function. So, when recording, you can change the deformation direction and the position (type) of the deformation interface,
Thus, a write-once type optical recording medium capable of multi-value recording is obtained, in which a reproduction signal having a different recording polarity in addition to a difference in recording mark length and amplitude is obtained. 4) The main absorption band at the time of unrecording exists on the long wavelength side with respect to the recording / reproducing wavelength through the undercoat layer on the substrate, and has the absorption function for the light of the recording / reproducing wavelength at the time of unrecording. An optical recording medium having a layer structure in which an organic material layer not sandwiched is sandwiched between an undercoating layer and an overcoating layer having a large refractive index difference with the organic material layer, and the undercoating layer or the overcoating layer has a light absorbing function. Therefore, the recording principle of the recording mark formation by the pressure from the organic material layer to the undercoat layer or the pressure from the organic material layer to the overcoat layer due to the state change of the organic material in the organic material layer, and the undercoat layer or It is possible to change the deformation direction of the recording mark part and the position (type) of the deformation interface during recording by the recording principle of recording mark formation due to stress relaxation of the overcoat layer or thermal expansion of the substrate. In addition to the difference in amplitude and amplitude, it is possible to obtain a reproduction signal with different recording polarities. A write-once type optical recording medium capable of multi-value recording. 5) The write-once type optical recording medium capable of multilevel recording according to any one of 1) to 4), wherein the recording / reproducing wavelength is 350 to 500 nm. 6) The multi-value recordable additional recording according to any one of 1) to 5), wherein the interface shape between the organic material layer and the overcoat layer is formed to be the same as the groove shape of the substrate. Optical recording medium. 7) On the substrate, an organic material layer having no absorption function for light having a recording / reproducing wavelength at the time of non-recording is provided on the substrate through an undercoat layer and an undercoat layer having a large refractive index difference from the organic material layer. For a write-once type optical recording medium that has a layer structure sandwiched between an undercoating layer and an undercoating layer or an overcoating layer and has a light absorbing function, which is capable of multilevel recording, the direction of deformation and the position of the deformation interface (type) ) Is changed so that reproduction signals having different recording polarities in addition to differences in recording mark length and amplitude can be obtained. 8) On the substrate, an organic material layer having no absorption function for light having a recording / reproducing wavelength at the time of non-recording is formed on the substrate through an undercoat layer and an undercoat layer having a large refractive index difference from the organic material layer. A multi-level recordable write-once type optical recording medium having a layer structure sandwiched between an organic material layer and an undercoating layer or an undercoating layer having a light absorbing function, and an organic material according to a change in state of the organic material in the organic material layer. Recording principle of recording mark formation by pressure from material layer to undercoat layer or pressure from organic material layer to overcoat layer, and recording mark formation by stress relaxation of undercoat layer or overcoat layer or thermal expansion of substrate By changing the recording principle, the direction of deformation of the recording mark portion and the position (type) of the deformation interface are changed at the time of recording, so that a reproduction signal having different recording polarities in addition to the difference in recording mark length and amplitude can be obtained. A multilevel recording method characterized by the above. 9) The main absorption band at the time of non-recording exists on the long wavelength side with respect to the recording / reproducing wavelength through the undercoat layer on the substrate, and has the absorption function for the light of the recording / reproducing wavelength at the time of unrecording. It has a layer structure in which an organic material layer is sandwiched between an undercoating layer and an overcoating layer having a large difference in refractive index from the organic material layer, and the undercoating layer or the overcoating layer has a light absorption function, and multilevel recording is possible. For a write-once type optical recording medium, by changing the deformation direction and the position (type) of the deformation interface at the time of recording, it is possible to obtain a reproduction signal having different recording polarities in addition to the difference in recording mark length and amplitude. A multilevel recording method characterized by the above. 10) The main absorption band at the time of unrecording exists on the long wavelength side with respect to the recording / reproducing wavelength through the undercoat layer on the substrate, and has the absorption function for the light of the recording / reproducing wavelength at the time of unrecording. It has a layer structure in which an organic material layer is sandwiched between an undercoating layer and an overcoating layer having a large difference in refractive index from the organic material layer, and the undercoating layer or the overcoating layer has a light absorption function, and multilevel recording is possible. Recording principle of recording marks for a write-once type optical recording medium by the pressure from the organic material layer to the undercoat layer or the pressure from the organic material layer to the overcoat layer due to the change of the state of the organic material in the organic material layer And the deformation principle of the recording mark portion and the position (type) of the deformation interface at the time of recording are changed according to the recording principle of the recording mark formation by the stress relaxation of the undercoat layer or the overcoat layer or the thermal expansion of the substrate. In order to obtain playback signals with different recording polarities in addition to differences in recording mark length and amplitude A multilevel recording method characterized by: 11) The multilevel recording method according to any one of 7) to 10), wherein the recording / reproducing wavelength is 350 to 500 nm.
【0008】以下、上記本発明について詳しく説明す
る。
(1)本発明の概要(特徴)
本発明では、記録の際に変形方向と変形界面の位置(種
類)を変えて多値記録を行うことにより、記録マーク長
や振幅の違いに加えて記録極性も異なる再生信号を得る
ことができる。また、本発明では、有機材料層中の有機
材料の状態変化に伴う有機材料層から下引層への圧力、
又は有機材料層から上引層への圧力による記録マーク形
成の記録原理と、下引層や上引層の応力緩和、又は基板
の熱膨張による記録マーク形成の記録原理を用い、これ
を制御することにより多値記録を行うことができる。即
ち、従来は記録極性が同一であったため〔いわゆるHi
gh to Low(ハイ・トゥー・ロー)記録か、L
ow to High(ロー・トゥー・ハイ)記録のど
ちらか一方〕、多値レベルの数を増やすと多値レベルの
判定がより困難になり、再生信頼性が大幅に低下すると
いう問題があったが、本発明では、記録マーク長や振幅
の違いだけでなく、記録極性も異なる再生信号が得られ
るので、より信頼性の高い追記型光記録媒体を提供する
ことができる。なお、本発明で言う「有機材料の状態変
化」とは、溶融、昇華、分解、爆発、構造変化等を指す
が、通常は分解、爆発が主であり、この場合、有機材料
に唯一要求されるのは、熱による分解特性(分解温度、
爆発性、明確な分解閾値の存在、分解スピード、分解量
等)が優れていることである。The present invention will be described in detail below. (1) Outline (Characteristics of the Present Invention) In the present invention, multi-valued recording is performed by changing the deformation direction and the position (type) of the deformation interface during recording, thereby recording in addition to the difference in recording mark length and amplitude. It is possible to obtain reproduced signals having different polarities. Further, in the present invention, the pressure from the organic material layer to the undercoat layer due to the state change of the organic material in the organic material layer,
Alternatively, the recording principle of recording mark formation by pressure from the organic material layer to the upper coating layer and the recording principle of recording mark formation by stress relaxation of the lower coating layer or upper coating layer or thermal expansion of the substrate are used to control this. This allows multi-valued recording. That is, since the recording polarities were the same in the past, the so-called Hi
gh to Low (high to low) recording or L
One of ow to High recording] and an increase in the number of multi-valued levels makes it more difficult to determine the multi-valued levels, and there is a problem that the reproduction reliability is significantly reduced. In the present invention, since the reproduction signals having different recording polarities as well as the difference in the recording mark length and the amplitude can be obtained, a more reliable write-once type optical recording medium can be provided. The "state change of the organic material" referred to in the present invention refers to melting, sublimation, decomposition, explosion, structural change, etc., but usually decomposition and explosion are the main, and in this case, only the organic material is required. The characteristics of decomposition by heat (decomposition temperature,
Explosiveness, existence of a clear decomposition threshold, decomposition speed, decomposition amount, etc.) are excellent.
【0009】(2)「変形方向と変形界面の位置(種
類)を変える」という表現の説明
本発明で言う「変形方向と変形界面の位置(種類)を変
える」という表現について説明する。変形方向とは、あ
る基準となる側から見た場合に、変形が凸状に生じてい
るか、或いは凹状に生じているかを意味する。また、変
形界面の位置(種類)とは、どの層の界面に凹凸状の変
形が生じているかを指す。変形界面としては、基板と下
引層の界面、下引層と有機材料層の界面、有機材料層と
上引層の界面、上引層とその上層(保護層、カバー層、
空気層等)との界面が存在する。本発明では、変形界面
が単一であっても良いし、上記の変形界面が複数組み合
わさっていてもよい。要は、変形界面の組み合わせと、
各界面の変形方向、変形量によって記録極性と記録マー
クのコントラストを変えるのである。本発明では、変形
界面の組み合わせ及び各界面の変形量を制御するが、こ
れらは各層の膜厚、記録波長に対する吸収係数の大小、
熱伝導率、硬度によって変化させることができる。最も
簡単なのは、記録パワーを制御することで、変形界面の
組み合わせ及び各界面の変形量を制御する方法である。(2) Explanation of expression "changing deformation direction and position (type) of deformation interface" The expression "changing deformation direction and position (type) of deformation interface" in the present invention will be explained. The deformation direction means whether the deformation occurs in a convex shape or a concave shape when viewed from a certain reference side. In addition, the position (type) of the deformation interface refers to which layer interface has the uneven deformation. As the deformation interface, the interface between the substrate and the undercoat layer, the interface between the undercoat layer and the organic material layer, the interface between the organic material layer and the overcoat layer, the overcoat layer and its upper layer (protective layer, cover layer,
There is an interface with the air layer). In the present invention, a single deformation interface may be used, or a plurality of the deformation interfaces may be combined. In short, a combination of deformation interfaces,
The recording polarity and the contrast of the recording mark are changed according to the deformation direction and the deformation amount of each interface. In the present invention, the combination of deformation interfaces and the amount of deformation of each interface are controlled. These include the thickness of each layer, the magnitude of the absorption coefficient with respect to the recording wavelength,
It can be changed by thermal conductivity and hardness. The simplest method is to control the recording power to control the combination of deformation interfaces and the deformation amount of each interface.
【0010】また、本発明では、各界面の変形方向を制
御するが、これは異なる記録原理を光記録媒体に持たせ
ることで実現する。即ち、有機材料層中の有機材料の状
態変化に伴う有機材料層から下引層への圧力、又は有機
材料層から上引層への圧力による記録マーク形成の記録
原理と、下引層や上引層の応力緩和、又は基板の熱膨張
による記録マーク形成の記録原理を併せ持たせることに
よって、各界面の変形方向を制御する。例えば、有機材
料層中の有機材料の状態変化に伴う有機材料層から下引
層への圧力による記録マーク形成の記録原理を用いるこ
とによって、基板や下引層を、基板側から見て手前側に
変形させることができる(ここでは凹状と表現する)。
また、下引層の応力緩和、又は基板の熱膨張による記録
マーク形成の記録原理を用いることによって、逆に、基
板や下引層を、基板側から見て奥側に変形させることが
できる(ここでは凸状と表現する)。本発明の重要な特
徴は、従来の変形を利用した記録原理では変形の方向が
一方に決まっていたが、本発明では、変形の方向を可変
にできる記録原理を用いた点である。Further, in the present invention, the deformation direction of each interface is controlled, which is realized by giving the optical recording medium a different recording principle. That is, the recording principle of recording mark formation by the pressure from the organic material layer to the undercoat layer or the pressure from the organic material layer to the overcoat layer due to the change of the state of the organic material in the organic material layer, and the undercoat layer or the overcoat layer. The deformation direction of each interface is controlled by having the recording principle of forming the recording mark by the stress relaxation of the pulling layer or the thermal expansion of the substrate. For example, by using the recording principle of forming a recording mark by the pressure from the organic material layer to the undercoat layer due to the change of the state of the organic material in the organic material layer, the substrate or the undercoat layer can be seen from the front side of the substrate or the undercoat layer. It can be transformed into (represented as concave here).
Further, by using the recording principle of forming a recording mark by relaxing the stress of the undercoat layer or thermal expansion of the substrate, the substrate or the undercoat layer can be deformed to the inner side when viewed from the substrate side ( Expressed here as convex). An important feature of the present invention is that the direction of deformation is fixed to one side in the conventional recording principle using deformation, but in the present invention, the recording principle in which the direction of deformation is variable is used.
【0011】(3)「有機材料層を、有機材料層との屈
折率差が大きい下引層と上引層とで挟み込む構造」とす
る理由
本発明では、「有機材料層を、有機材料層との屈折率差
が大きい下引層と上引層とで挟み込む構造」を有するこ
とを特徴とする。この構造によって、反射率の向上、信
号品質の向上を図ることができ、或いは記録によって生
じた変形方向や変形界面の位置(種類)の違いによっ
て、記録マーク長や振幅の違いに加えて記録極性も異な
る再生信号を効率よく発生させることができる。なお、
有機材料層と下引層及び上引層との屈折率差は、通常
0.5以上とする。(3) The reason why the "organic material layer is sandwiched between the undercoating layer and the overcoating layer having a large difference in refractive index from the organic material layer" is used in the present invention. Has a structure in which it is sandwiched between an undercoating layer and an overcoating layer having a large difference in refractive index from the above. With this structure, it is possible to improve the reflectance and the signal quality, or due to the difference in the deformation direction and the position (type) of the deformation interface caused by the recording, in addition to the difference in the recording mark length and the amplitude, the recording polarity. , It is possible to efficiently generate different reproduction signals. In addition,
The refractive index difference between the organic material layer and the undercoat layer or the overcoat layer is usually 0.5 or more.
【0012】(4)有機材料層に用いられる有機材料の
要件
本発明では、記録極性を可変とするために、記録マーク
の変形方向(凸変形か、或いは凹変形か)を制御する。
従来の光記録媒体(図1参照)の基本変形原理であっ
た、基板の熱膨張による記録マーク形成では、基板は必
ず有機材料層の方向へ変形し、逆の方向へは変形しな
い。これは、基板の熱膨張による力が十分大きく、これ
を阻害する力、或いはこれに逆らう大きな力が存在しな
いためである。そこで本発明者は、基板の熱膨張に対
し、この熱膨張による変形方向と逆方向の力を生じさせ
る手段について検討し、その結果、有機材料の状態変化
に伴う力(特に分解・爆発力)が利用できることを見出
したものである。しかし、この状態変化に伴う力を有効
に利用するためには、有機材料層と隣接する層との界面
近傍の有機材料が最も状態変化を起し易いようにする必
要があるが、従来の層構成では、有機材料層の中央部が
最も高温になるため、有機材料層と隣接する層との界面
近傍の有機材料は十分な状態変化を起さない。そこで、
本発明では、有機材料層と隣接する層との界面近傍の有
機材料が最も状態変化を起し易いようにするため、有機
材料層に隣接して光吸収層(光吸収機能を有する下引層
又は上引層)を設ける構造とした。(4) Requirements of Organic Material Used for Organic Material Layer In the present invention, the deformation direction (convex deformation or concave deformation) of the recording mark is controlled in order to make the recording polarity variable.
In forming a recording mark by thermal expansion of the substrate, which is the basic deformation principle of the conventional optical recording medium (see FIG. 1), the substrate is always deformed in the direction of the organic material layer and is not deformed in the opposite direction. This is because the force due to the thermal expansion of the substrate is sufficiently large, and there is no force that inhibits it or a large force that opposes it. Therefore, the present inventor examined means for producing a force in the direction opposite to the deformation direction due to the thermal expansion of the substrate due to the thermal expansion, and as a result, the force accompanying the state change of the organic material (especially decomposition / explosive force). Is available. However, in order to effectively utilize the force associated with this state change, it is necessary to make it easy for the organic material in the vicinity of the interface between the organic material layer and the adjacent layer to cause the state change. In the configuration, since the central part of the organic material layer has the highest temperature, the organic material in the vicinity of the interface between the organic material layer and the adjacent layer does not change its state sufficiently. Therefore,
In the present invention, in order to make the state of the organic material near the interface between the organic material layer and the adjacent layer most likely to change, the light absorbing layer (the undercoat layer having a light absorbing function) is adjacent to the organic material layer. Alternatively, a structure in which an overcoat layer) is provided.
【0013】この光吸収層の吸収係数は、有機材料層の
吸収係数よりも十分大きく設定されるため(光吸収層は
光吸収機能を有するのに対し、有機材料層は記録再生波
長の光に対して光吸収機能を有しないから当然そのよう
になる)、光吸収層近傍の有機材料が最も高温になり、
有機材料の状態変化に伴う力により、従来とは変形方向
が逆の記録を行うことが可能となる。そして、この光吸
収層を設けたことで、従来の、記録層と光吸収層の機能
を兼ね備えていた有機材料層から光吸収機能を分離する
ことができる。これによって、有機材料層に課せられる
厳しい光学定数条件が緩和されるため、本発明の追記型
光記録媒体は、350〜500nm程度の青色レーザ波
長領域でも容易に記録することが可能となる(従来の層
構成では、有機材料層に厳しい光学定数条件が存在した
ため、青色レーザ波長領域に対応できる有機材料が殆ん
ど存在せず、有機材料を用いた追記型光記録媒体の実現
は困難であった)。更に、従来の有機材料を用いた追記
型光記録媒体では、有機材料層で熱を発生させる必要が
あったため、有機材料層を薄膜化できず、深い溝(例え
ば150〜180nm)を必要としていたが、本発明の
記録原理によって有機材料の薄膜化が可能となり、成形
性に優れた浅い溝を有する基板を用いることが出来るの
で、信頼性の高い追記型光記録媒体を提供することが可
能となる。Since the absorption coefficient of this light absorption layer is set to be sufficiently larger than that of the organic material layer (while the light absorption layer has a light absorption function, the organic material layer emits light of a recording / reproducing wavelength). On the other hand, since it does not have a light absorption function, it naturally becomes so), the organic material in the vicinity of the light absorption layer becomes the highest temperature,
Due to the force associated with the change in the state of the organic material, it is possible to perform recording in a deformation direction opposite to the conventional one. By providing this light absorbing layer, it is possible to separate the light absorbing function from the organic material layer which has the conventional functions of both the recording layer and the light absorbing layer. Since this alleviates the severe optical constant conditions imposed on the organic material layer, the write-once type optical recording medium of the present invention can easily record even in the blue laser wavelength region of about 350 to 500 nm (conventional). In the layer structure of (1), since there were severe optical constant conditions in the organic material layer, there were almost no organic materials compatible with the blue laser wavelength region, and it was difficult to realize a write-once type optical recording medium using organic materials. ). Further, in the write-once type optical recording medium using the conventional organic material, it is necessary to generate heat in the organic material layer, so that the organic material layer cannot be thinned and a deep groove (for example, 150 to 180 nm) is required. However, the recording principle of the present invention makes it possible to reduce the thickness of the organic material, and since a substrate having a shallow groove excellent in moldability can be used, it is possible to provide a highly reliable write-once type optical recording medium. Become.
【0014】本発明で用いた「未記録時の主吸収帯が記
録再生波長に対して長波長側に存在し、かつ記録再生波
長の光に対して吸収機能を有しない有機材料層」、或い
は「未記録時に記録再生波長の光に対して吸収機能を有
しない有機材料層」という表現における、「記録再生波
長の光に対して吸収機能を有しない」とは、有機材料層
単独の吸収機能では、有機材料層の隣接層を変形させた
り、有機材料自身を状態変化させるような温度に至らな
いことを意味する(即ち、実質上、光吸収層として必要
な吸収機能を果さないことを意味する)。従って、具体
的には、有機材料の吸収係数が小さい場合や、膜厚が薄
い場合を指すことになる。また、「未記録時の主吸収帯
が記録再生波長に対して長波長側に存在し、かつ記録再
生波長の光に対して吸収機能を有しない有機材料層」、
或いは「未記録時に記録再生波長の光に対して吸収機能
を有しない有機材料層」が、本発明の光記録媒体の構成
要件として重要な理由は、本発明では従来の追記型光記
録媒体に用いられる光吸収機能を有する有機材料に代え
て、比較的大きな吸収係数を有する下引層や上引層を用
いることにより、有機材料層での吸収機能を低下させて
反射率の向上を図ることが出来るためである。The "organic material layer used in the present invention, in which the main absorption band at the time of unrecording exists on the long wavelength side with respect to the recording / reproducing wavelength and which does not have an absorbing function for the light having the recording / reproducing wavelength", or In the expression "organic material layer that does not have a function of absorbing light having a recording / reproducing wavelength when not recorded", "does not have a function of absorbing light having a recording / reproducing wavelength" means the absorption function of the organic material layer alone. Then, it means that the temperature does not reach a temperature at which the layer adjacent to the organic material layer is deformed or the state of the organic material itself is changed (that is, it does not substantially fulfill the absorption function required as the light absorption layer. means). Therefore, specifically, it means a case where the absorption coefficient of the organic material is small or a case where the film thickness is thin. Further, "an organic material layer in which the main absorption band at the time of unrecording exists on the long wavelength side with respect to the recording / reproducing wavelength and which does not have an absorbing function for light having the recording / reproducing wavelength",
Alternatively, the reason why the “organic material layer having no absorption function for light having a recording / reproducing wavelength when not recorded” is important as a constituent of the optical recording medium of the present invention is that the conventional write-once type optical recording medium is used in the present invention. By using an undercoating layer or an overcoating layer having a relatively large absorption coefficient in place of the used organic material having a light absorption function, it is possible to reduce the absorption function in the organic material layer and improve the reflectance. This is because you can
【0015】また、前述したように、反射率の向上、信
号品質の向上、或いは記録によって生じた変形方向や変
形界面の位置(種類)の違いによって、記録マーク長や
振幅の違いに加えて記録極性の異なる信号を効率よく発
生させるためには、有機材料層を、有機材料層との屈折
率差が大きい下引層と上引層とで挟み込む構造が適して
おり、そのためには有機材料層の屈折率を低く設定した
方が、下引層と上引層の材料選択の上で有利である。何
故ならば、本発明の好ましい層構成として、例えば、基
板/下引層(光吸収層)/有機材料層/上引層(反射
層)が挙げられるが、この層構成を考えた場合、反射層
の屈折率は通常0.1程度で非常に小さく、光吸収層の
屈折率は例えば2.0〜4.0程度であって、有機材料
層と光吸収層の屈折率差が小さくなり易い。そこで、こ
の屈折率差を大きくすることが重要となるが、それに
は、有機材料層の屈折率を低く設定すれば、有機材料層
と光吸収層の屈折率差を大きくし、かつ光吸収層の選択
の幅を広げることが出来るからである。Further, as described above, due to the improvement of the reflectance, the improvement of the signal quality, the difference in the deformation direction and the position (type) of the deformation interface caused by the recording, in addition to the difference in the recording mark length and the amplitude, the recording is performed. In order to efficiently generate signals with different polarities, a structure in which an organic material layer is sandwiched between an undercoating layer and an overcoating layer, which have a large refractive index difference with the organic material layer, is suitable. It is advantageous to set a low refractive index of the above in selecting materials for the undercoat layer and the overcoat layer. The preferred layer structure of the present invention is, for example, substrate / undercoating layer (light absorbing layer) / organic material layer / upper coating layer (reflective layer). The refractive index of the layer is usually about 0.1, which is very small, and the refractive index of the light absorbing layer is, for example, about 2.0 to 4.0, and the difference in refractive index between the organic material layer and the light absorbing layer tends to be small. . Therefore, it is important to increase the difference in refractive index. To this end, if the refractive index of the organic material layer is set to be low, the difference in refractive index between the organic material layer and the light absorption layer is increased, and This is because the range of choices can be expanded.
【0016】従って、「未記録時の主吸収帯が記録再生
波長に対して長波長側に存在し、かつ記録再生波長の光
に対して吸収機能を有しない有機材料層」、或いは「未
記録時に記録再生波長の光に対して吸収機能を有しない
有機材料層」とすることにより、即ち、有機材料の最大
吸収帯と記録再生波長を大きくずらすことにより有機材
料層の屈折率を低くすることが可能となる。また、記録
再生波長が500nm以上、例えばDVD系光記録媒体
の記録再生波長である650nm近傍、或いはCD系光
記録媒体の記録再生波長である780nm近傍では、有
機材料層の要件として「未記録時に記録再生波長の光に
対して吸収機能を有しない有機材料層」を満足すれば十
分であり、有機材料の主吸収帯の波長と記録再生波長の
大小関係は殆んど問題にならない。Therefore, "an organic material layer whose main absorption band at the time of unrecording exists on the long wavelength side with respect to the recording / reproducing wavelength and which does not have an absorbing function for light of the recording / reproducing wavelength" or "unrecorded" By lowering the refractive index of the organic material layer, it is sometimes necessary to use an "organic material layer that does not have a function of absorbing light with a recording / reproducing wavelength", that is, by greatly shifting the recording / reproducing wavelength from the maximum absorption band of the organic material. Is possible. In addition, when the recording / reproducing wavelength is 500 nm or more, for example, near the recording / reproducing wavelength of 650 nm for the DVD-based optical recording medium or near 780 nm for the recording / reproducing wavelength of the CD-based optical recording medium, the requirement of the organic material layer is “when unrecorded”. It suffices if the “organic material layer having no absorption function for the light of the recording / reproducing wavelength” is satisfied, and the size relationship between the wavelength of the main absorption band of the organic material and the recording / reproducing wavelength is hardly a problem.
【0017】しかし、記録再生波長が350〜500n
m程度の青色レーザ゛領域、例えば400nm近傍に設
定される場合、未記録時の主吸収帯が記録再生波長に対
して短波長側に存在し、かつ記録再生波長の光に対して
吸収機能を有しないような状態にすることは、有機材料
の分子の大きさを非常に小さくすることを意味し、これ
は有機材料の状態変化に伴う有機材料層から下引層への
圧力、又は有機材料層から上引層への圧力が大幅に低下
することを意味するため、本発明の記録原理を用いる追
記型光記録媒体には好ましくない。そこで、記録再生波
長が350〜500nm、例えば400nm近傍に設定
される場合は、有機材料の状態変化に伴う有機材料層か
ら下引層への圧力、又は有機材料層から上引層への圧力
を十分に発生させるために、分子骨格の大きい有機材料
を選択し、未記録時の主吸収帯が記録再生波長に対して
長波長側に存在し、かつ記録再生波長の光に対して光吸
収機能を有しない有機材料層とすることが好ましい。However, the recording / reproducing wavelength is 350 to 500 n.
When a blue laser region of about m, for example, near 400 nm is set, the main absorption band at the time of unrecording is on the short wavelength side with respect to the recording / reproducing wavelength and has an absorption function for the light with the recording / reproducing wavelength. The state of not having means that the size of the molecule of the organic material is made extremely small. This is the pressure from the organic material layer to the undercoat layer due to the change of the state of the organic material, or the organic material. This means that the pressure from the layer to the overcoat layer is significantly reduced, and is not preferable for the write-once type optical recording medium using the recording principle of the present invention. Therefore, when the recording / reproducing wavelength is set to 350 to 500 nm, for example, near 400 nm, the pressure from the organic material layer to the undercoat layer or the pressure from the organic material layer to the overcoat layer due to the state change of the organic material is set. In order to generate enough, an organic material with a large molecular skeleton is selected, the main absorption band at the time of unrecording is on the long wavelength side with respect to the recording / reproducing wavelength, and the light absorption function for the light of the recording / reproducing wavelength. It is preferable that the organic material layer does not have.
【0018】(5)有機材料層と上引層の界面形状が、
基板の溝形状と同一となるように形成する理由
有機材料層の膜厚は任意であり、その形成形態も任意で
ある。この形成形態とは、有機材料層の表面形状(有機
材料層と上引層の界面形状)がどのような形状であるか
を指し、例えば、有機材料層の表面形状が基板形状と同
一(図8参照)となる場合や、有機材料層の表面形状が
フラット(図9参照)となる場合がある。本発明では、
比較的記録極性の変化が生じ易くなる条件の一つとし
て、有機材料層の表面形状が重要であることを見出した
ものであり、有機材料層の表面形状が基板形状と同一
(図8参照)となる場合は、記録極性の変化が生じ易く
なる(記録極性が変化する条件が緩和される)ことを見
出したものである。しかし、ここで「同一となるように
形成する」という記載の意味するところは、文字通り同
一である場合だけでなく、有機材料層と上引層の界面形
状が、ほぼ基板の溝形状に倣って形成されている場合、
即ち、基板上にスパッタリング等の通常の膜形成方法で
各層を形成したときに、多少の膜厚のばらつきはあるも
のの、ほぼ基板の溝形状に倣って各層が形成されている
ような場合を含むものとする。なお、本発明の追記型光
記録媒体は、上記各層以外に、従来より公知の中間層、
バックコート層等の種々の層を設けてもよい。(5) The shape of the interface between the organic material layer and the overcoat layer is
The reason why the organic material layer is formed so as to have the same groove shape as the substrate The film thickness of the organic material layer is arbitrary, and the formation form thereof is also arbitrary. This form of formation refers to what kind of shape the surface shape of the organic material layer (interface shape between the organic material layer and the overcoat layer) is. For example, the surface shape of the organic material layer is the same as the substrate shape (Fig. 8)) or the surface shape of the organic material layer may be flat (see FIG. 9). In the present invention,
It was found that the surface shape of the organic material layer is important as one of the conditions in which the recording polarity is relatively likely to change, and the surface shape of the organic material layer is the same as the substrate shape (see FIG. 8). In this case, it is found that the recording polarity is likely to change (the condition for changing the recording polarity is relaxed). However, the meaning of the description "to be formed so as to be the same" is not limited to the case where they are literally the same, and the interface shape between the organic material layer and the overcoat layer is almost the same as the groove shape of the substrate. If formed,
That is, when each layer is formed on a substrate by a normal film forming method such as sputtering, there is a case in which each layer is formed almost along the groove shape of the substrate, although there is some variation in film thickness. Let's assume. The write-once type optical recording medium of the present invention, in addition to the above layers, a conventionally known intermediate layer,
Various layers such as a back coat layer may be provided.
【0019】(6)他の記録原理の併用について
本発明では、上記記録原理に加えて、レーザ光の照射に
よる下引層又は上引層の発熱によって有機材料層に状態
変化を生じ、該状態変化による記録再生波長での吸収係
数の増加による記録原理を併用してもよい。但し、この
記録原理では、有機材料層の屈折率や膜厚が大きく変化
しない限り、記録極性がHigh to Lowとなる
ので、この記録原理を併用するのは、前記変形による記
録原理において記録極性がHigh to Lowとな
る場合に限られる。この有機材料層の吸収係数の増加に
よる記録原理を、図18〜図20を参照しつつ説明す
る。図18に示すような未記録状態の吸収スペクトルを
有する有機材料を選択し、この有機材料を状態変化(特
に分解、爆発)させると、分解により有機材料を構成し
ていた分子や分子団の吸収が発生する。この吸収は、通
常、分解、爆発前の有機材料の吸収よりも短波長である
ため、元の有機材料の大きな吸収帯よりも短波長側での
吸収係数が増加する(記録状態の吸収スペクトル参
照)。この短波長側の吸収波長の変化の大きい範囲と記
録再生波長(例えば図の矢印の位置)とを合わせれば、
記録後の記録再生波長における吸収係数を増加させるこ
とができるので、これによって変調度を発生させること
が可能となる。(6) Concomitant use of other recording principles In the present invention, in addition to the above recording principle, the organic material layer undergoes a state change due to heat generation of the undercoating layer or the overcoating layer due to the irradiation of laser light, and this state The recording principle of increasing the absorption coefficient at the recording / reproducing wavelength due to the change may be used together. However, according to this recording principle, the recording polarity becomes High to Low unless the refractive index and the film thickness of the organic material layer are significantly changed. It is limited to the case of High to Low. The recording principle due to the increase of the absorption coefficient of the organic material layer will be described with reference to FIGS. When an organic material having an absorption spectrum in an unrecorded state as shown in FIG. 18 is selected and the state of this organic material is changed (particularly decomposed or exploded), the absorption of molecules or molecular groups constituting the organic material by decomposition is absorbed. Occurs. This absorption usually has a shorter wavelength than the absorption of the organic material before decomposition and explosion, so the absorption coefficient on the shorter wavelength side than the large absorption band of the original organic material increases (see absorption spectrum in recorded state). ). If the range where the change in absorption wavelength on the short wavelength side is large and the recording / reproducing wavelength (for example, the position of the arrow in the figure) are combined,
Since the absorption coefficient at the recording / reproducing wavelength after recording can be increased, it is possible to generate the degree of modulation.
【0020】この記録原理についてもう少し詳しく説明
すると、本発明で用いる有機材料は、小さな分子や分子
団が結合して、或いは、錯体や会合体等を形成して大き
な共役系を形成した有機材料であって、分子や分子団が
持っていた固有の吸収波長(図19の吸収スペクトル
A、Bに相当)よりも長波長側に大きな吸収帯を持ち、
個々の分子や分子団が持っていた固有の吸収帯が消滅、
又は減衰した吸収スペクトルを持つ(図20の吸収スペ
クトルCに相当)。このような有機材料に対し、図20
で示すようなλ1を記録再生波長として選択すると、未
記録時はλ1での吸収が少なかった状態から、分解、爆
発などによって、大きな分子を形成していた分子や分子
団が持つ固有の吸収が増加し(図19参照)、λ1での
吸収も増加し、吸収係数の変化による記録部が形成でき
る。従って、ただ小さな分子や分子団が結合しているだ
けであって、共役系の広がりが形成されないような分子
は、図20のような状態、即ち、分子や分子団が持って
いた固有の吸収帯が消滅又は減衰し、新たに大きな鋭い
吸収帯が形成されるような状態が実現されないため、記
録前後での吸収係数の変化が大きくならず、記録ピット
を形成することができない。Explaining this recording principle in a little more detail, the organic material used in the present invention is an organic material in which small molecules or molecular groups are bound to each other, or a complex or association is formed to form a large conjugated system. Therefore, it has a larger absorption band on the long wavelength side than the intrinsic absorption wavelength of the molecule or molecular group (corresponding to absorption spectra A and B in FIG. 19),
The unique absorption band of each molecule or group disappears,
Alternatively, it has an attenuated absorption spectrum (corresponding to absorption spectrum C in FIG. 20). For such an organic material, FIG.
If λ1 as shown in is selected as the recording / reproducing wavelength, the absorption that is small at λ1 when unrecorded causes the absorption unique to the molecule or molecular group that formed a large molecule due to decomposition or explosion. 19 (see FIG. 19), the absorption at λ1 also increases, and the recording portion can be formed by the change of the absorption coefficient. Therefore, a molecule in which only a small molecule or a molecular group is bound and a conjugate system does not form a spread is in the state as shown in FIG. 20, that is, the intrinsic absorption of the molecule or the molecular group. Since the band disappears or decays and a state in which a new large sharp absorption band is formed is not realized, the change in the absorption coefficient before and after recording does not become large, and the recording pit cannot be formed.
【0021】(7)各層の材料について
基板の素材としては、熱的、機械的に優れた特性を有
し、基板側から(基板を通して)記録再生が行われる場
合には光透過特性にも優れたものであれば、特別な制限
はない。具体例としては、ポリカーボネート、ポリメタ
クリル酸メチル、非晶質ポリオレフィン、セルロースア
セテート、ポリエチレンテレフタレートなどが挙げられ
るが、ポリカーボネートや非晶質ポリオレフィンが好ま
しい。基板の厚さは用途により異なり、特に制限はな
い。(7) Material of each layer The material of the substrate has excellent thermal and mechanical properties, and has excellent light transmission properties when recording / reproducing is performed from the substrate side (through the substrate). There is no special limitation as long as it is good. Specific examples include polycarbonate, polymethylmethacrylate, amorphous polyolefin, cellulose acetate, polyethylene terephthalate, and the like, and polycarbonate and amorphous polyolefin are preferable. The thickness of the substrate depends on the application and is not particularly limited.
【0022】光を吸収し熱を発生させる光吸収層として
機能する下引層又は上引層には、比較的熱伝導率の低い
材料が適している。比較的低い熱伝導率の材料を選択す
る理由は、効率よく(低記録パワーで)各層の界面を変
形させるためであり、更には、効率よく(低記録パワー
で)有機材料を状態変化させるためである。なお、ここ
で言う比較的熱伝導率が低いとは、記録によって局所的
に有機材料を状態変化させるだけの温度に達するような
熱伝導率であることを意味する。以上の点から、光吸収
層として機能する下引層や上引層には、SiC等のセラ
ミックス、Si等の半金属、Ge等の金属、又はそれら
の混合物を用いることが好ましい。また、下引層や上引
層の厚さは、通常20〜500Åとする。A material having a relatively low thermal conductivity is suitable for the undercoating layer or the overcoating layer that functions as a light absorbing layer that absorbs light and generates heat. The reason for selecting a material having a relatively low thermal conductivity is to efficiently deform the interface of each layer (at low recording power), and further to efficiently change the state of the organic material (at low recording power). Is. The term "relatively low thermal conductivity" as used herein means that the thermal conductivity reaches a temperature at which the state of the organic material is locally changed by recording. From the above points, it is preferable to use ceramics such as SiC, semimetals such as Si, metals such as Ge, or a mixture thereof for the undercoating layer and the overcoating layer that function as the light absorption layer. Further, the thickness of the undercoat layer and the overcoat layer is usually 20 to 500 Å.
【0023】上記下引層や上引層の材料となるセラミッ
クスとしては、Al2O3、MgO、BeO、Zr
O2、UO2、ThO2などの単純酸化物系の酸化物;
SiO2、2MgO・SiO2、MgO・SiO2、C
aO・SiO3、ZrO2・SiO2、3Al2O3・
2SiO2、2MgO・2Al2O3・5SiO2、L
i 2O・Al2O3・4SiO2などのケイ酸塩系の酸
化物;Al2TiO5、MgAl2O4、Ca10(P
O4)6(OH)2、BaTiO3、LiNbO3、P
ZT〔Pb(Zr,Ti)O3〕、PLZT〔(Pb,
La)(Zr,Ti)O3〕、フェライトなどの複酸化
物系の酸化物;Si3N4、Si6−ZAl ZOZN
8−Z、AlN、BN、TiNなどの窒化物系の非酸化
物;SiC、B 4C、TiC、WCなどの炭化物系の非
酸化物;LaB6、TiB2、ZrB2などのホウ化物
系の非酸化物;CdS、MoS2などの硫化物系の非酸
化物;MoSi2などのケイ化物系の非酸化物;アモル
ファス炭素、黒鉛、ダイヤモンド等の炭素系の非酸化物
などを用いることができる。また、金属としては、A
u、Al、Ag、Cu、Pd、Pt、Ti、Ta、C
r、Ni、Fe、及びこれらの合金を用いることができ
る。A ceramic which is a material for the undercoat layer and the overcoat layer.
As a cous, AlTwoOThree, MgO, BeO, Zr
OTwo, UOTwo, ThOTwoSimple oxide-based oxides such as;
SiOTwo2MgO / SiOTwo, MgO / SiOTwo, C
aO ・ SiOThree, ZrOTwo・ SiOTwo3 AlTwoOThree・
2 SiOTwo2MgO / 2AlTwoOThree・ 5 SiOTwo, L
i TwoO ・ AlTwoOThree・ 4SiOTwoSilicate-based acids such as
Compound; AlTwoTiO5, MgAlTwoOFour, Ca10(P
OFour)6(OH)Two, BaTiOThree, LiNbOThree, P
ZT [Pb (Zr, Ti) OThree], PLZT [(Pb,
La) (Zr, Ti) OThree], Double oxidation such as ferrite
Physical oxides; SiThreeNFour, Si6-ZAl ZOZN
8-ZNon-oxidizing nitrides such as Al, AlN, BN and TiN
Thing; SiC, B FourCarbide-based non-carbon materials such as C, TiC, and WC
Oxide; LaB6, TiBTwo, ZrBTwoBoride such as
System non-oxides: CdS, MoSTwoSulfide-based non-acid such as
Compound; MoSiTwoNon-oxides of silicides such as; Amole
Carbon-based non-oxides such as faux carbon, graphite and diamond
Etc. can be used. As the metal, A
u, Al, Ag, Cu, Pd, Pt, Ti, Ta, C
r, Ni, Fe, and alloys of these can be used
It
【0024】有機材料層に用いられる有機材料として
は、いわゆる色素が好ましい。また、下引層や上引層を
十分変形させるためには、昇華性又は分解・爆発性が高
い色素、或いは昇華性又は分解・爆発性の高い置換基が
導入された色素が好ましい。また、高い分解・爆発性を
確保するには、分子骨格が大きい有機材料が好ましい。
更に、構造変化によって体積変化を起こす色素も用いる
ことができる。上記の要件を満足する色素としては、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、クロコニウム系、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
フェノチアジン系染料、及び金属錯体化合物などが挙げ
られる。色素層の膜厚は、100Å〜10μm、好まし
くは100〜2000Åが適当である。As the organic material used for the organic material layer, a so-called dye is preferable. Further, in order to sufficiently deform the undercoat layer or the overcoat layer, a dye having a high sublimation property or decomposition / explosion property, or a dye having a substituent group having a high sublimation property or decomposition / explosion property introduced therein is preferable. Further, in order to secure high decomposition and explosiveness, an organic material having a large molecular skeleton is preferable.
Further, a dye that causes a volume change due to a structure change can also be used. Dyes satisfying the above requirements include polymethine dyes, naphthalocyanine dyes, phthalocyanine dyes, squarylium dyes, croconium dyes, pyrylium dyes, naphthoquinone dyes, anthraquinone (indanthrene) dyes, xanthene dyes, triphenylmethane dyes, azulene dyes. , Tetrahydrocholine-based dyes, phenanthrene-based dyes, triphenothiazine-based dyes, and metal complex compounds. The film thickness of the dye layer is 100 Å to 10 μm, preferably 100 to 2000 Å.
【0025】色素層の形成は、蒸着、スパッタリング、
CVD、溶剤塗布などの通常の手段によって行なうこと
ができる。塗布法を用いる場合には、上記染料などを有
機溶剤に溶解して、スプレー、ローラーコーティング、
ディッピング、スピンコーティングなどの慣用のコーテ
ィング法で行なうことができる。用いられる有機溶剤と
しては、一般にメタノール、エタノール、イソプロパノ
ールなどアルコール類;アセトン、メチルエチルケト
ン、シクロヘキサノンなどのケトン類;N,N−ジメチ
ルアセトアミド、N,N−ジメチルホルムアミドなどの
アミド類;ジメチルスルホキシドなどのスルホキシド
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などのエー
テル類;酢酸メチル、酢酸エチルなどのエステル類;ク
ロロホルム、塩化メチレン、ジクロルエタン、四塩化炭
素、トリクロルエタンなどの脂肪族ハロゲン化炭素類;
ベンゼン、キシレン、モノクロルベンゼン、ジクロルベ
ンゼンなどの芳香族類;メトキシエタノール、エトキシ
エタノールなどのセロソルブ類;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などの炭化水素
類などが挙げられる。The dye layer is formed by vapor deposition, sputtering,
It can be carried out by a usual means such as CVD or solvent coating. When the coating method is used, the dye or the like is dissolved in an organic solvent, spraying, roller coating,
It can be performed by a conventional coating method such as dipping or spin coating. As the organic solvent used, alcohols such as methanol, ethanol and isopropanol are generally used; ketones such as acetone, methyl ethyl ketone and cyclohexanone; amides such as N, N-dimethylacetamide and N, N-dimethylformamide; sulfoxides such as dimethyl sulfoxide. Ethers such as tetrahydrofuran, dioxane, diethyl ether and ethylene glycol monomethyl ether; Esters such as methyl acetate and ethyl acetate; Aliphatic halogenated carbons such as chloroform, methylene chloride, dichloroethane, carbon tetrachloride and trichloroethane;
Aromatic compounds such as benzene, xylene, monochlorobenzene, and dichlorobenzene; cellosolves such as methoxyethanol and ethoxyethanol; hexane, pentane,
Hydrocarbons such as cyclohexane and methylcyclohexane are included.
【0026】光吸収層として機能しない下引層又は上引
層としては、金属又はセラミックスが好ましい。この金
属又はセラミックスは、反射率の向上又は記録再生特性
の向上を図るために、有機材料層との屈折率差のある材
料を用いることが好ましい。下引層と上引層のうち、入
射レーザ光に対し手前側の層に光吸収能がある場合に
は、反射率の向上又は記録再生特性の向上を図るため
に、入射レーザ光に対し奥側の層は金属であることが好
ましい。逆に、下引層と上引層のうち、入射レーザ光に
対し奥側の層に光吸収能がある場合には、反射率の向上
又は記録再生特性の向上を図るために、入射レーザ光に
対し手前側の層は、記録再生波長に対し吸収係数が小さ
な(0.02以下程度)セラミックスであることが好ま
しい。上記金属としては、Au、Al、Cu、Cr、A
g、Ti及びこれらの合金からなる群より選択される金
属が好ましく、上記記録再生波長(ここでは青色領域近
傍)に対し吸収係数が小さなセラミックスとしては、前
述したセラミックスやZnS・SiO2等が好ましい。
これらの材料は、一般に真空蒸着又はスパッタリング法
により50〜5000Å、好ましくは50〜3000Å
の厚さで形成される。The undercoating layer or the overcoating layer that does not function as the light absorbing layer is preferably metal or ceramics. As the metal or ceramic, it is preferable to use a material having a refractive index difference from that of the organic material layer in order to improve the reflectance or the recording / reproducing characteristics. Of the undercoating layer and the overcoating layer, if the layer on the front side with respect to the incident laser light has a light absorbing ability, in order to improve the reflectance or the recording / reproducing characteristics, the depth of the incident laser light is increased. The side layer is preferably metallic. On the contrary, in the case of the undercoating layer and the overcoating layer, if the layer on the back side with respect to the incident laser light has a light absorbing ability, the incident laser light is used to improve the reflectance or the recording / reproducing characteristics. On the other hand, the front layer is preferably made of ceramics having a small absorption coefficient (about 0.02 or less) with respect to the recording / reproducing wavelength. As the metal, Au, Al, Cu, Cr, A
A metal selected from the group consisting of g, Ti and alloys thereof is preferable, and as the ceramics having a small absorption coefficient for the recording / reproducing wavelength (here, near the blue region), the above-mentioned ceramics, ZnS.SiO 2 and the like are preferable. .
These materials are generally 50 to 5000 Å, preferably 50 to 3000 Å by vacuum deposition or sputtering.
Formed with a thickness of.
【0027】[0027]
【実施例】以下、実施例及び比較例により本発明を具体
的に説明するが、本発明はこれらの実施例により何ら限
定されるものではない。EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples.
【0028】実施例1
(本発明の追記型光記録媒体によって、記録マーク長や
振幅の違いに加えて記録極性も異なる再生信号が得られ
ることを明らかにし、また、その記録原理を確認するた
めの実施例)
溝深さ50nmの案内溝を有するポリカーボネート基板
上に、スパッタ法により光吸収層として機能する膜厚1
0nmの下引層(SiC)を設け、その上に、下記〔化
1〕で示される有機材料をスピンコート法で成膜し(膜
厚約60nm)、更にその上に、膜厚100nmの上引
層(Ag)を設けて光記録媒体を作製した。Example 1 (To clarify that the write-once type optical recording medium of the present invention can provide a reproduction signal having different recording polarities in addition to the difference in recording mark length and amplitude, and to confirm the recording principle. Example) On a polycarbonate substrate having a guide groove with a groove depth of 50 nm, a film thickness of 1 which functions as a light absorption layer by a sputtering method.
An undercoating layer (SiC) having a thickness of 0 nm is provided, and an organic material represented by the following [Chemical formula 1] is formed thereon by a spin coating method (film thickness of about 60 nm). An optical recording medium was produced by providing a coating layer (Ag).
【化1】 [Chemical 1]
【0029】上記光記録媒体に対し、パルステック工業
(株)製の光ディスク評価装置DDU−1000(波
長:405nm、NA:0.65)を用いて、下記の記
録条件で、記録時の記録パワーをある時間間隔で6.0
(mW)と10.0(mW)に切替えて記録を行った。
<記録条件>
記録線密度:1T=0.0917(μm)
記録線速度:6.0(m/s)
記録ストラテジ:Basic strategy(基本ストラテジー)
Ttop−Tmp=1.40−0.75(T)
記録パワー:6.0(mW)、10.0(mW)
記録パターン:8−16変調信号
その結果、図2に示すように、記録パワーが6.0(m
W)の時はLow to High記録が行え、記録パ
ワーが10.0(mW)の時はHigh toLow記
録が行えることが確認できた。Using the optical recording medium DPU-1000 (wavelength: 405 nm, NA: 0.65) manufactured by Pulstec Industrial Co., Ltd. on the above optical recording medium, the recording power at the time of recording under the following recording conditions. At a time interval of 6.0
Recording was performed by switching between (mW) and 10.0 (mW). <Recording conditions> Recording linear density: 1T = 0.0917 (μm) Recording linear velocity: 6.0 (m / s) Recording strategy: Basic strategy T top −T mp = 1.40−0.75 (T) Recording power: 6.0 (mW), 10.0 (mW) Recording pattern: 8-16 modulated signal As a result, as shown in FIG. 2, the recording power is 6.0 (mW).
It was confirmed that when the recording power is W), the Low to High recording can be performed, and when the recording power is 10.0 (mW), the High to Low recording can be performed.
【0030】次いで、この記録が前述したような記録原
理に基づいて行われているかどうかを確認するため、S
iCと有機材料層界面の変形状態をAFM(アトミック
フォースマイクロスコープ、Atomic force
microscope)により測定した。図3は、記
録パワーが6.0(mW)の時に発生したLow to
High記録部分の、SiCと有機材料層界面の変形
状態を三次元で表した結果である(下側が基板であ
る)。なお、図3では、濃淡によって高さを表し、色が
薄い部分が高く、色が濃い部分が低い。図4は、図3を
二次元的に表した図(a)と、記録トラックの断面図
(凹凸形状)を表した図(b)である。これらの図に示
された結果から、記録パワーが6.0(mW)の時に発
生したLow to High記録部分は、SiCと有
機材料層界面が基板側へ変形(凹変形)していることが
確認できた。Next, in order to confirm whether this recording is performed based on the recording principle as described above, S
The deformation state of the interface between the iC and the organic material layer is measured by AFM (atomic force microscope, atomic force).
It was measured by microscope). FIG. 3 shows the Low to which occurred when the recording power was 6.0 (mW).
This is the result of three-dimensionally expressing the deformation state of the interface between the SiC and the organic material layer in the High recording portion (the lower side is the substrate). Note that in FIG. 3, the height is represented by shading, in which a light color portion is high and a dark color portion is low. FIG. 4 is a two-dimensional view of FIG. 3A and a cross-sectional view (concave and convex shape) of a recording track (b). From the results shown in these figures, it is found that the interface between the SiC and the organic material layer is deformed (concave deformed) toward the substrate side in the Low to High recording portion generated when the recording power is 6.0 (mW). It could be confirmed.
【0031】一方、図5は、記録パワーが10.0(m
W)の時に発生したHigh toLow記録部分の、
SiCと有機材料層界面の変形状態を三次元で表した結
果である(下側が基板である)。なお、図5では、濃淡
によって高さを表し、色が薄い部分が高く、色が濃い部
分が低い。図6は、図5を二次元的に表した図(a)
と、記録トラックの断面図(凹凸形状)を表した図
(b)である。これらの図に示された結果から、記録パ
ワーが10.0(mW)の時に発生したHigh to
Low記録部分は、SiCと有機材料層界面が基板側
とは反対方向へ変形(凸変形)していることが確認でき
た。On the other hand, in FIG. 5, the recording power is 10.0 (m
W) of High to Low recording part
It is the result of three-dimensionally expressing the deformation state of the interface between SiC and the organic material layer (the lower side is the substrate). Note that, in FIG. 5, the height is represented by shading, in which a light color portion is high and a dark color portion is low. FIG. 6 is a two-dimensional view of FIG. 5 (a).
3B is a diagram (b) showing a cross-sectional view (uneven shape) of the recording track. From the results shown in these figures, High to which occurred when the recording power was 10.0 (mW)
It was confirmed that the interface between the SiC and the organic material layer was deformed (convexly deformed) in the direction opposite to the substrate side in the Low recording portion.
【0032】以上の結果から、本発明の追記型光記録媒
体は、記録マーク長や振幅に加えて記録極性も変えて記
録できることが明らかになり、この記録極性は、少なく
ともSiCと有機材料層の界面形状の変形方向の差異に
よって生じていることが確認できた。なお、この実施例
ではAFM像を見易くするためランド部に記録を行った
が、本発明はランド記録に限定されるものではない。ま
た、変形形状の測定のし易さからSiCと有機材料層の
界面形状を測定したが、他の界面が同時に変形していて
も構わない。更に、従来の有機材料を用いた光記録媒体
では、有機材料層で熱を発生させる必要があったため、
有機材料層を薄膜化できず、深い溝(例えば150〜1
80nm)を必要としていたが、本発明の記録原理によ
って、有機材料の薄膜化が可能となり、50nmという
非常に浅い溝を有する基板を適用できることが確かめら
れた。このことは信頼性の高い光記録媒体を作製する上
で、非常に大きなメリットとなる。From the above results, it becomes clear that the write-once type optical recording medium of the present invention can record by changing the recording polarity in addition to the recording mark length and the amplitude, and this recording polarity is at least that of SiC and the organic material layer. It was confirmed that it was caused by the difference in the deformation direction of the interface shape. In this embodiment, recording is performed on the land portion to make the AFM image easy to see, but the present invention is not limited to land recording. Further, the interface shape between the SiC and the organic material layer was measured for the ease of measuring the deformed shape, but other interfaces may be deformed at the same time. Furthermore, in the conventional optical recording medium using an organic material, it was necessary to generate heat in the organic material layer,
The organic material layer cannot be thinned and deep grooves (for example, 150 to 1) are formed.
However, the recording principle of the present invention made it possible to make the organic material into a thin film, and it was confirmed that a substrate having a very shallow groove of 50 nm can be applied. This is a great merit in producing a highly reliable optical recording medium.
【0033】比較例1
実施例1における有機材料に代えてポリメチルメタクリ
レートを用いた点以外は、実施例1と同様の実験を行っ
た。その結果、6.0(mW)で記録した部分も、1
0.0(mW)で記録した部分も記録極性が同一であ
り、また、SiCとポリマー層の界面は、図5〜図6と
同様に基板と反対方向(凸変形)に変形していた。これ
によって、実施例1においてSiCと有機材料層の界面
が基板側へ変形(凹変形)した現象は、有機材料の働き
によるものであり、有機材料の状態変化(分解・爆発)
がこの凹変形に寄与していることが裏付けられた。Comparative Example 1 The same experiment as in Example 1 was conducted except that polymethyl methacrylate was used instead of the organic material in Example 1. As a result, the portion recorded at 6.0 (mW) is also 1
The recording polarity was the same in the portion recorded at 0.0 (mW), and the interface between the SiC and the polymer layer was deformed in the direction opposite to the substrate (convex deformation) as in FIGS. As a result, the phenomenon that the interface between the SiC and the organic material layer is deformed (depressed) toward the substrate side in Example 1 is due to the action of the organic material, and the state change (decomposition / explosion) of the organic material.
It has been proved that has contributed to this concave deformation.
【0034】実施例2
実際に記録部の変形方向や変形界面の位置(種類)を正
確に測定することは非常に困難であるから(実施例1で
は、下引層と有機材料層の界面の状態のみを評価し
た)、ここでは光学シュミレーションによって、変形方
向と変形界面の位置(種類)を変えることで、記録マー
ク長や振幅の違いに加えて記録極性も異なる再生信号が
得られることを証明する。下記の計算条件下で、次の
(i)〜(iv)のように記録条件を変えて、再生信号が
どのように変化するかを計算した。
(i)記録部分(ランド部又はグルーブ部)
(ii)有機材料層の形成状態〔有機材料層の表面形状が
基板形状と同一(図8参照)、又は、有機材料層の表面
形状はフラット(図9参照)〕
(iii)記録マーク形成界面〔下引層と有機材料層の界
面のみが変形(図10、11、14、15参照)、又
は、下引層/有機材料層の界面と有機材料層/上引層の
界面が変形(図12、13、16、17参照)〕
(iv)記録マーク変形方向〔基板側へ凹変形(図14〜
17参照)、又は、上引層側へ凸変形(図10〜13参
照)〕Example 2 It is extremely difficult to accurately measure the deformation direction of the recording portion and the position (type) of the deformation interface in practice (in Example 1, the interface between the undercoat layer and the organic material layer). Only the condition was evaluated), and here it was proved that by changing the deformation direction and the position (type) of the deformation interface by optical simulation, it is possible to obtain a reproduction signal with different recording polarities in addition to the difference in recording mark length and amplitude. To do. Under the following calculation conditions, the recording conditions were changed as shown in (i) to (iv) below, and how the reproduced signal changed was calculated. (I) Recording portion (land portion or groove portion) (ii) Forming state of organic material layer [The surface shape of the organic material layer is the same as the substrate shape (see FIG. 8), or the surface shape of the organic material layer is flat ( (See FIG. 9)] (iii) Recording mark forming interface (only the interface between the undercoat layer and the organic material layer is deformed (see FIGS. 10, 11, 14 and 15), or the interface between the undercoat layer / organic material layer and the organic layer) The interface between the material layer and the overcoat layer is deformed (see FIGS. 12, 13, 16 and 17). (Iv) Recording mark deformation direction [Concave deformation toward the substrate (FIG. 14-
17), or convex deformation toward the upper coating layer side (see FIGS. 10 to 13)]
【0035】<計算条件詳細>以下、長さ、大きさは記
録再生波長λを単位として表した。
・ビーム形状:ガウス分布
・振幅が1/eとなる半径(x方向、y方向):600
0λ、6000λ
・対物レンズ開口半径:3000λ
・対物レンズNA(開口数):0.60
・対物レンズ焦点距離:5000λ
・溝形状〔A、B、C、D、ζ(図7参照)〕:(0.
2λ、0.8λ、1.0λ、1.8525λ、0.13
75λ)
・基板屈折率:1.60(基板側入射)
・下引層複素屈折率:2.810−i0.561、膜厚
=0.025λ
・有機材料層複素屈折率:1.500−i0.050、
膜厚=0.150λ
・上引層複素屈折率:0.1078−i2.0495、
膜厚=0.250λ
・検出器:4分割PD
・検出器の半径(x方向、y方向):3000λ、30
00λ
・記録マーク長さ、幅、高さ:1.0λ、0.60λ、
±0.10λ<Details of Calculation Conditions> In the following, the length and size are expressed in terms of the recording / reproducing wavelength λ.・ Beam shape: Gaussian distribution ・ Radius with amplitude of 1 / e (x direction, y direction): 600
0λ, 6000λ · Objective lens aperture radius: 3000λ · Objective lens NA (numerical aperture): 0.60 · Objective lens focal length: 5000λ · Groove shape [A, B, C, D, ζ (see FIG. 7)]: ( 0.
2λ, 0.8λ, 1.0λ, 1.8525λ, 0.13
75λ) -Substrate refractive index: 1.60 (incident on substrate side) -Undercoat layer complex refractive index: 2.810-i0.561, film thickness = 0.025λ-Organic material layer complex refractive index: 1.500-i0 .050,
Film thickness = 0.150λ ・ Upper layer complex refractive index: 0.1078-i2.0495,
Film thickness = 0.250λ ・ Detector: 4-division PD ・ Radius of detector (x direction, y direction): 3000λ, 30
00λ ・ Record mark length, width, height: 1.0λ, 0.60λ,
± 0.10λ
【0036】計算の結果は、図21〜図24に示す通り
である。図21は、グルーブに記録した場合で、有機材
料層の形成状態は、図8に示すように、有機材料層の表
面形状が基板形状と同一となるように形成されている場
合の結果である。なお、記録部の高さは±0.10λと
した(記録再生波長を400nmとした場合は±40n
mとなる)。凡例「+40nm−0,4」は、記録部が
図16であることを、凡例「−40nm−0,4」は、
記録部が図12であることを、凡例「+40nm−0,
2」は、記録部が図14であることを、凡例「−40n
m−0,2」は、記録部が図10であることを示す。な
お、以上の図ではグルーブ部に記録された状態が示され
ているが、ランド部の場合も、記録部の変形方向と変形
界面の位置(種類)は同一である。The calculation results are as shown in FIGS. FIG. 21 shows the result when the recording is made in the groove and the organic material layer is formed so that the surface shape of the organic material layer is the same as the substrate shape as shown in FIG. . The height of the recording portion was ± 0.10λ (± 40n when the recording / reproducing wavelength was 400 nm).
m). The legend "+40 nm-0,4" indicates that the recording portion is shown in FIG. 16, and the legend "-40 nm-0,4" indicates
The fact that the recording part is shown in FIG. 12 means that the legend “+40 nm-0,
2 "indicates that the recording unit is shown in FIG.
"m-0,2" indicates that the recording unit is shown in FIG. In the above figures, the state of recording in the groove portion is shown, but also in the case of the land portion, the deformation direction of the recording portion and the position (type) of the deformation interface are the same.
【0037】図22は、ランドに記録した場合で、有機
材料層の形成状態は、図8に示すように、有機材料層の
表面形状が基板形状と同一となるように形成されている
場合の結果である。なお、記録部の高さは±0.10λ
とした(記録再生波長を400nmとした場合は±40
nmとなる)。凡例「+40nm−0,4」は、記録部
が図16であることを、凡例「−40nm−0,4」
は、記録部が図12であることを、凡例「+40nm−
0,2」は、記録部が図14であることを、凡例「−4
0nm−0,2」は、記録部が図10であることを示
す。FIG. 22 shows a case of recording on a land, and the organic material layer is formed so that the surface shape of the organic material layer is the same as the substrate shape as shown in FIG. The result. The height of the recording area is ± 0.10λ
(± 40 when the recording / reproducing wavelength is 400 nm)
nm). The legend "+40 nm-0,4" indicates that the recording part is shown in FIG. 16, and the legend "-40 nm-0,4".
Indicates that the recording part is as shown in FIG.
0, 2 ”indicates that the recording unit is shown in FIG.
0 nm-0,2 "indicates that the recording unit is shown in FIG.
【0038】図23は、グルーブに記録した場合で、有
機材料層の形成状態は、図9に示すように、有機材料層
の表面形状がフラットとなるように形成されている場合
の結果である。なお、記録部の高さは±0.10λとし
た(記録再生波長を400nmとした場合は±40nm
となる)。凡例「+40nm−0,4」は、記録部が図
17であることを、凡例「−40nm−0,4」は、記
録部が図13であることを、凡例「+40nm−0,
2」は、記録部が図15であることを、凡例「−40n
m−0,2」は、記録部が図11であることを示す。な
お、以上の図ではグルーブ部に記録された状態が示され
ているが、ランド部の場合も、記録部の変形方向と変形
界面の位置(種類)は同一である。FIG. 23 shows the case where recording is made in the groove, and the state of formation of the organic material layer is the result when the surface shape of the organic material layer is flat as shown in FIG. . The height of the recording portion was ± 0.10λ (± 40 nm when the recording / reproducing wavelength was 400 nm).
Will be). The legend "+40 nm-0,4" indicates that the recording portion is shown in FIG. 17, and the legend "-40 nm-0,4" indicates that the recording portion is shown in FIG.
2 "indicates that the recording unit is shown in FIG.
"m-0, 2" indicates that the recording unit is shown in FIG. In the above figures, the state of recording in the groove portion is shown, but also in the case of the land portion, the deformation direction of the recording portion and the position (type) of the deformation interface are the same.
【0039】図24は、ランドに記録した場合で、有機
材料層の形成状態は、図9に示すように、有機材料層の
表面形状がフラットとなるように形成されている場合の
結果である。なお、記録部の高さは±0.10λとした
(記録再生波長を400nmとした場合は±40nmと
なる)。凡例「+40nm−0,4」は、記録部が図1
7であることを、凡例「−40nm−0,4」は、記録
部が図13であることを、凡例「+40nm−0,2」
は、記録部が図15であることを、凡例「−40nm−
0,2」は、記録部が図11であることを示す。FIG. 24 shows a case where recording is performed on a land and the organic material layer is formed so that the surface shape of the organic material layer is flat as shown in FIG. . The height of the recording section was ± 0.10λ (± 40 nm when the recording / reproducing wavelength was 400 nm). In the legend "+40 nm-0,4", the recording part is shown in FIG.
7, the legend “−40 nm−0,4” indicates that the recording portion is FIG. 13, and the legend “+40 nm−0,2”.
Indicates that the recording part is as shown in FIG.
"0, 2" indicates that the recording unit is shown in FIG.
【0040】この図21〜図24の結果より、記録マー
クの変形方向と変形界面の位置(種類)を変えること
で、記録極性を制御できるという考え方が、原理的に正
しいことが証明された。なお、図24に示す結果から、
有機材料層の形成状態が、図9に示すように、有機材料
層の表面形状がフラットとなるように形成されている場
合には、ランド記録では記録極性の変化が現われ難いこ
とが分る。つまり、請求項6の「有機材料層と上引層の
界面形状が、基板の溝形状と同一となるように形成され
ていることを特徴とする多値記録可能な光記録媒体」
が、多値記録を可能にする有機材料を用いた光記録媒体
として好ましいことが確認された。但し、各層の複素屈
折率や、記録による各層の複素屈折率の変化、或いは記
録マークの高さ、形状によって記録極性が変化する条件
が変るため、有機材料層の表面形状がフラットとなるよ
うに形成されている場合を否定するものではない。From the results of FIGS. 21 to 24, it was proved in principle that the idea that the recording polarity can be controlled by changing the deformation direction of the recording mark and the position (type) of the deformation interface is correct. From the results shown in FIG. 24,
As shown in FIG. 9, when the organic material layer is formed such that the surface shape of the organic material layer is flat, it is understood that the recording polarity hardly appears in the land recording. That is, in claim 6, "an optical recording medium capable of multilevel recording, wherein the interface shape between the organic material layer and the overcoat layer is formed to be the same as the groove shape of the substrate".
However, it was confirmed that it is preferable as an optical recording medium using an organic material that enables multilevel recording. However, since the condition that the recording polarity changes depending on the complex refractive index of each layer, the change of the complex refractive index of each layer due to recording, or the height and shape of the recording mark changes, the surface shape of the organic material layer should be flat. It does not deny the case of being formed.
【0041】[0041]
【発明の効果】本発明によれば、多値レベルの数を増や
しながらも精度の高い多値記録が可能で、350〜50
0nm程度の青色レーザ領域にも適用可能な追記型光記
録媒体、及び多値記録方法を提供できる。According to the present invention, it is possible to perform highly accurate multi-value recording while increasing the number of multi-value levels.
A write-once type optical recording medium applicable to a blue laser region of about 0 nm and a multilevel recording method can be provided.
【図1】従来の光記録媒体の層構成を示す図。FIG. 1 is a diagram showing a layer structure of a conventional optical recording medium.
【図2】本発明の記録媒体で記録極性の異なる記録マー
クが形成されたことを示す図。FIG. 2 is a diagram showing that recording marks having different recording polarities are formed on the recording medium of the present invention.
【図3】本発明の記録媒体でLow to High記
録が行われた部分をAFMで観察した結果を示す図。FIG. 3 is a view showing a result of observing a portion where low-to-high recording is performed on the recording medium of the present invention with an AFM.
【図4】本発明の記録媒体でLow to High記
録が行われた部分をAFMで観察した結果を示す別の
図。
(a) 図3を二次元的に表した図
(b) 記録トラックの断面図(凹凸形状)FIG. 4 is another diagram showing a result of observing a portion where Low to High recording is performed on the recording medium of the present invention by AFM. (A) Two-dimensional representation of FIG. 3 (b) Cross-sectional view of recording track (uneven shape)
【図5】本発明の記録媒体でHigh to Low記
録が行われた部分をAFMで観察した結果を示す図。FIG. 5 is a view showing a result of observing with AFM a portion where High to Low recording is performed on the recording medium of the present invention.
【図6】本発明の記録媒体でHigh to Low記
録が行われた部分をAFMで観察した結果を示す別の
図。
(a) 図5を二次元的に表した図
(b) 記録トラックの断面図(凹凸形状)FIG. 6 is another diagram showing a result of observing a portion where High to Low recording is performed on the recording medium of the present invention by AFM. (A) Two-dimensional view of FIG. 5 (b) Cross-sectional view of recording track (uneven shape)
【図7】実施例2で用いた溝形状のパラメータを説明す
るための図。FIG. 7 is a view for explaining parameters of groove shapes used in Example 2;
【図8】本発明の層構成を示す図であり、有機材料層の
1形成形態を説明するための図。FIG. 8 is a diagram showing a layer structure of the invention, and is a diagram for explaining one formation mode of an organic material layer.
【図9】本発明の層構成を示す図であり、有機材料層の
他の1形成形態を説明するための図。FIG. 9 is a diagram showing a layer structure of the invention, and is a diagram for explaining another one formation mode of the organic material layer.
【図10】有機材料層の形成形態と、記録マークの形成
形態の一例を示す図。FIG. 10 is a diagram showing an example of a formation form of an organic material layer and a formation form of a recording mark.
【図11】有機材料層の形成形態と、記録マークの形成
形態の他の一例を示す図。FIG. 11 is a diagram showing another example of the formation form of the organic material layer and the formation form of the recording mark.
【図12】有機材料層の形成形態と、記録マークの形成
形態の他の一例を示す図。FIG. 12 is a diagram showing another example of the formation form of the organic material layer and the formation form of the recording mark.
【図13】有機材料層の形成形態と、記録マークの形成
形態の他の一例を示す図。FIG. 13 is a view showing another example of the formation form of the organic material layer and the formation form of the recording mark.
【図14】有機材料層の形成形態と、記録マークの形成
形態の他の一例を示す図。FIG. 14 is a diagram showing another example of the formation form of the organic material layer and the formation form of the recording mark.
【図15】有機材料層の形成形態と、記録マークの形成
形態の他の一例を示す図。FIG. 15 is a diagram showing another example of the formation form of the organic material layer and the formation form of the recording mark.
【図16】有機材料層の形成形態と、記録マークの形成
形態の他の一例を示す図。FIG. 16 is a diagram showing another example of the formation form of the organic material layer and the formation form of the recording mark.
【図17】有機材料層の形成形態と、記録マークの形成
形態の他の一例を示す図。FIG. 17 is a diagram showing another example of the formation form of the organic material layer and the formation form of the recording mark.
【図18】有機材料の吸収係数の増加による記録原理を
説明するための図。FIG. 18 is a diagram for explaining a recording principle due to an increase in absorption coefficient of an organic material.
【図19】有機材料の吸収係数の増加による記録原理を
実現し得る有機材料層の特性を説明するための図。FIG. 19 is a diagram for explaining the characteristics of the organic material layer that can realize the recording principle by increasing the absorption coefficient of the organic material.
【図20】有機材料の吸収係数の増加による記録原理を
実現し得る有機材料層の特性を説明するための図。FIG. 20 is a diagram for explaining characteristics of an organic material layer that can realize the recording principle by increasing the absorption coefficient of the organic material.
【図21】有機材料層が図8のように形成され、グルー
ブ部に記録が行われた場合の再生信号を計算した結果を
示す図。FIG. 21 is a diagram showing a result of calculating a reproduction signal when an organic material layer is formed as shown in FIG. 8 and recording is performed in a groove portion.
【図22】有機材料層が図8のように形成され、ランド
部に記録が行われた場合の再生信号を計算した結果を示
す図。FIG. 22 is a diagram showing a result of calculating a reproduction signal when an organic material layer is formed as shown in FIG. 8 and recording is performed on a land portion.
【図23】有機材料層が図9のように形成され、グルー
ブ部に記録が行われた場合の再生信号を計算した結果を
示す図。FIG. 23 is a diagram showing a result of calculating a reproduction signal when an organic material layer is formed as shown in FIG. 9 and recording is performed in a groove portion.
【図24】有機材料層が図9のように形成され、ランド
部に記録が行われた場合の再生信号を計算した結果を示
す図。FIG. 24 is a diagram showing a result of calculating a reproduction signal when an organic material layer is formed as shown in FIG. 9 and recording is performed on a land portion.
A ランドの上面端部と、隣接するグルーブの該ランド
に近い方の底面端部との幅
B ランドの上面端部と、隣接するグルーブの該ランド
から遠い方の底面端部との幅
C ランドの上面端部と、隣接するランドの、前記ラン
ドに近い方の上面端部との幅
D ランドの上面端部と、隣接するランドの、前記ラン
ドから遠い方の上面端部との幅
ζ ランドの高さ(溝の深さ)A Width between the top edge of the land and the bottom edge of the adjacent groove that is closer to the land B Width between the top edge of the land and the bottom edge of the adjacent groove that is farther from the land C land Width between the upper surface end of the land and the upper surface end of the adjacent land closer to the land D The upper surface end of the land and the upper end of the adjacent land farther from the land ζ land Height (depth of groove)
Claims (11)
記録再生波長の光に対して吸収機能を有しない有機材料
層を、該有機材料層との屈折率差が大きい下引層と上引
層とで挟み込む層構造を有し、下引層又は上引層が光吸
収機能を有する光記録媒体であって、記録の際に変形方
向と変形界面の位置(種類)を変えることができ、これ
により記録マーク長や振幅の違いに加えて記録極性も異
なる再生信号が得られることを特徴とする多値記録可能
な追記型光記録媒体。1. An organic material layer which does not have a function of absorbing light of a recording / reproducing wavelength when unrecorded is formed on a substrate through an undercoating layer, and the undercoating layer has a large difference in refractive index from the organic material layer. An optical recording medium having a layer structure sandwiched between a layer and an overcoat layer, wherein the undercoat layer or the overcoat layer has a light absorbing function, and changes the deformation direction and the position (type) of the deformation interface during recording. A write-once type optical recording medium capable of multi-value recording, which is capable of producing a reproduction signal having a different recording polarity in addition to a difference in recording mark length and amplitude.
記録再生波長の光に対して吸収機能を有しない有機材料
層を、該有機材料層との屈折率差が大きい下引層と上引
層とで挟み込む層構造を有し、下引層又は上引層が光吸
収機能を有する光記録媒体であって、有機材料層中の有
機材料の状態変化に伴う有機材料層から下引層への圧
力、又は有機材料層から上引層への圧力による記録マー
ク形成の記録原理と、下引層や上引層の応力緩和、又は
基板の熱膨張による記録マーク形成の記録原理によっ
て、記録の際に記録マーク部の変形方向と変形界面の位
置(種類)を変えることができ、これにより記録マーク
長や振幅の違いに加えて記録極性も異なる再生信号が得
られることを特徴とする多値記録可能な追記型光記録媒
体。2. An organic material layer which does not have a function of absorbing light of a recording / reproducing wavelength when unrecorded is formed on a substrate through an undercoat layer, and the undercoat layer has a large difference in refractive index from the organic material layer. An optical recording medium having a layer structure sandwiched between a layer and an overcoating layer, wherein the undercoating layer or the overcoating layer has a light absorbing function, and the organic material layer from the organic material layer accompanying a change in state of the organic material in the organic material layer Recording principle of recording mark formation by pressure on the undercoat layer or pressure from the organic material layer to the overcoat layer, and recording principle of recording mark formation by stress relaxation of the undercoat layer or the overcoat layer or thermal expansion of the substrate It is possible to change the deformation direction of the recording mark part and the position (type) of the deformation interface at the time of recording, and this makes it possible to obtain a reproduction signal having different recording polarities in addition to the difference in recording mark length and amplitude. A write-once type optical recording medium capable of multi-value recording.
主吸収帯が記録再生波長に対して長波長側に存在し、か
つ未記録時に記録再生波長の光に対して吸収機能を有し
ない有機材料層を、該有機材料層との屈折率差が大きい
下引層と上引層とで挟み込む層構造を有し、下引層又は
上引層が光吸収機能を有する光記録媒体であって、記録
の際に変形方向と変形界面の位置(種類)を変えること
ができ、これにより記録マーク長や振幅の違いに加えて
記録極性も異なる再生信号が得られることを特徴とする
多値記録可能な追記型光記録媒体。3. A main absorption band at the time of unrecording exists on the long wavelength side with respect to the recording / reproducing wavelength on the substrate through an undercoat layer, and absorbs light of the recording / reproducing wavelength at the time of unrecording. A light having a layer structure in which an organic material layer having no function is sandwiched between an undercoating layer and an overcoating layer having a large refractive index difference with the organic material layer, and the undercoating layer or the overcoating layer has a light absorbing function. It is a recording medium, and it is possible to change the deformation direction and the position (type) of the deformation interface at the time of recording, so that a reproduction signal having different recording polarities in addition to the difference in recording mark length and amplitude is obtained. A write-once type optical recording medium capable of multi-value recording.
主吸収帯が記録再生波長に対して長波長側に存在し、か
つ未記録時に記録再生波長の光に対して吸収機能を有し
ない有機材料層を、該有機材料層との屈折率差が大きい
下引層と上引層とで挟み込む層構造を有し、下引層又は
上引層が光吸収機能を有する光記録媒体であって、有機
材料層中の有機材料の状態変化に伴う有機材料層から下
引層への圧力、又は有機材料層から上引層への圧力によ
る記録マーク形成の記録原理と、下引層や上引層の応力
緩和、又は基板の熱膨張による記録マーク形成の記録原
理によって、記録の際に記録マーク部の変形方向と変形
界面の位置(種類)を変えることができ、これにより記
録マーク長や振幅の違いに加えて記録極性も異なる再生
信号が得られることを特徴とする多値記録可能な追記型
光記録媒体。4. A main absorption band at the time of unrecording exists on the long wavelength side with respect to the recording / reproducing wavelength on the substrate through an undercoat layer, and absorbs light of the recording / reproducing wavelength at the time of unrecording. A light having a layer structure in which an organic material layer having no function is sandwiched between an undercoating layer and an overcoating layer having a large refractive index difference with the organic material layer, and the undercoating layer or the overcoating layer has a light absorbing function. A recording medium, the recording principle of forming a recording mark by the pressure from the organic material layer to the undercoat layer or the pressure from the organic material layer to the overcoat layer due to the state change of the organic material in the organic material layer, and The deformation direction of the recording mark portion and the position (type) of the deformation interface can be changed during recording by the recording principle of the recording mark formation by the stress relaxation of the pulling layer or the overcoat layer or the thermal expansion of the substrate. A reproduction signal with different recording polarities in addition to differences in recording mark length and amplitude can be obtained. A write-once type optical recording medium capable of multi-value recording.
ることを特徴とする請求項1〜4の何れかに記載の多値
記録可能な追記型光記録媒体。5. The write-once type optical recording medium capable of multilevel recording according to claim 1, wherein the recording / reproducing wavelength is 350 to 500 nm.
の溝形状と同一となるように形成されていることを特徴
とする請求項1〜5の何れかに記載の多値記録可能な追
記型光記録媒体。6. The multilevel recording according to claim 1, wherein the interface shape between the organic material layer and the overcoat layer is formed to be the same as the groove shape of the substrate. Possible write-once type optical recording medium.
記録再生波長の光に対して吸収機能を有しない有機材料
層を、該有機材料層との屈折率差が大きい下引層と上引
層とで挟み込む層構造を有し、下引層又は上引層が光吸
収機能を有する多値記録可能な追記型光記録媒体に対
し、記録の際に変形方向と変形界面の位置(種類)を変
えることにより、記録マーク長や振幅の違いに加えて記
録極性も異なる再生信号が得られるようにすることを特
徴とする多値記録方法。7. An organic material layer, which has no absorption function for light having a recording / reproducing wavelength when not recorded, is formed on a substrate through an undercoating layer, and the undercoating layer has a large difference in refractive index from the organic material layer. A write-once type optical recording medium having a layer structure sandwiched between a layer and an overcoat layer, and the undercoat layer or the overcoat layer having a light absorption function and capable of multi-valued recording is used to record the deformation direction and the deformation interface at the time of recording. A multilevel recording method characterized in that a reproduction signal having different recording polarities in addition to the difference in recording mark length and amplitude can be obtained by changing the position (type).
記録再生波長の光に対して吸収機能を有しない有機材料
層を、該有機材料層との屈折率差が大きい下引層と上引
層とで挟み込む層構造を有し、下引層又は上引層が光吸
収機能を有する多値記録可能な追記型光記録媒体に対
し、有機材料層中の有機材料の状態変化に伴う有機材料
層から下引層への圧力、又は有機材料層から上引層への
圧力による記録マーク形成の記録原理と、下引層や上引
層の応力緩和、又は基板の熱膨張による記録マーク形成
の記録原理によって、記録の際に記録マーク部の変形方
向と変形界面の位置(種類)を変え、これにより記録マ
ーク長や振幅の違いに加えて記録極性も異なる再生信号
が得られるようにすることを特徴とする多値記録方法。8. An organic material layer, which does not have a function of absorbing light having a recording / reproducing wavelength when unrecorded, is formed on a substrate through an undercoating layer by undercoating with a large difference in refractive index from the organic material layer. A layer structure sandwiched between a layer and an overcoat layer, the state change of the organic material in the organic material layer for a multi-value recordable write-once optical recording medium in which the undercoat layer or the overcoat layer has a light absorbing function. The recording principle of the recording mark formation by the pressure from the organic material layer to the undercoat layer or the pressure from the organic material layer to the overcoat layer and the stress relaxation of the undercoat layer or the overcoat layer, or the thermal expansion of the substrate Depending on the recording principle of recording mark formation, the deformation direction of the recording mark portion and the position (type) of the deformation interface are changed at the time of recording, whereby a reproduction signal having different recording polarities in addition to the difference in recording mark length and amplitude can be obtained. A multi-valued recording method characterized by:
主吸収帯が記録再生波長に対して長波長側に存在し、か
つ未記録時に記録再生波長の光に対して吸収機能を有し
ない有機材料層を、該有機材料層との屈折率差が大きい
下引層と上引層とで挟み込む層構造を有し、下引層又は
上引層が光吸収機能を有する多値記録可能な追記型光記
録媒体に対し、記録の際に変形方向と変形界面の位置
(種類)を変えることにより、記録マーク長や振幅の違
いに加えて記録極性も異なる再生信号が得られるように
することを特徴とする多値記録方法。9. A main absorption band at the time of non-recording exists on the long wavelength side with respect to the recording / reproducing wavelength through an undercoat layer on a substrate, and absorbs light of the recording / reproducing wavelength at the time of unrecording. It has a layered structure in which an organic material layer having no function is sandwiched between an undercoating layer and an overcoating layer having a large difference in refractive index from the organic material layer, and the undercoating layer or the overcoating layer has a light absorbing function. By changing the deformation direction and the position (type) of the deformation interface at the time of recording with respect to the write-once type optical recording medium capable of value recording, a reproduction signal having a different recording polarity in addition to a difference in recording mark length and amplitude can be obtained. A multi-valued recording method characterized by:
の主吸収帯が記録再生波長に対して長波長側に存在し、
かつ未記録時に記録再生波長の光に対して吸収機能を有
しない有機材料層を、該有機材料層との屈折率差が大き
い下引層と上引層とで挟み込む層構造を有し、下引層又
は上引層が光吸収機能を有する多値記録可能な追記型光
記録媒体に対し、有機材料層中の有機材料の状態変化に
伴う有機材料層から下引層への圧力、又は有機材料層か
ら上引層への圧力による記録マーク形成の記録原理と、
下引層や上引層の応力緩和、又は基板の熱膨張による記
録マーク形成の記録原理によって、記録の際に記録マー
ク部の変形方向と変形界面の位置(種類)を変え、これ
により記録マーク長や振幅の違いに加えて記録極性の異
なる再生信号が得られるようにすることを特徴とする多
値記録方法。10. A main absorption band at the time of unrecording exists on the long wavelength side with respect to the recording / reproducing wavelength on the substrate through the undercoat layer,
Further, it has a layer structure in which an organic material layer having no absorption function for light having a recording / reproducing wavelength when not recorded is sandwiched between an undercoating layer and an overcoating layer having a large difference in refractive index from the organic material layer. For a write-once type optical recording medium capable of multi-valued recording, in which the undercoating layer or the overcoating layer has a light absorbing function, the pressure from the organic material layer to the undercoating layer due to the state change of the organic material in the organic material layer, or the organic The recording principle of recording mark formation by pressure from the material layer to the overcoat layer,
Depending on the recording principle of recording mark formation due to the stress relaxation of the undercoat layer or the overcoat layer or the thermal expansion of the substrate, the position (type) of the deformation direction and the deformation interface of the recording mark part is changed during recording. A multilevel recording method characterized in that a reproduction signal having a different recording polarity in addition to a difference in length and amplitude is obtained.
あることを特徴とする請求項7〜10の何れかに記載の
多値記録方法。11. The multilevel recording method according to claim 7, wherein a recording / reproducing wavelength is 350 to 500 nm.
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JP2003263778A true JP2003263778A (en) | 2003-09-19 |
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Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20070037095A1 (en) * | 2005-07-28 | 2007-02-15 | Noboru Sasa | Write-once-read-many optical disk having low-to-high recording property accommodating short wavelength recording |
US7876666B2 (en) | 2004-04-02 | 2011-01-25 | Kabushiki Kaisha Toshiba | Write-once information recording medium and coloring matter material therefor |
US20110141872A1 (en) * | 2005-04-14 | 2011-06-16 | Hideo Ando | Storage medium, reproducing method, and recording method |
US20130215729A1 (en) * | 2005-03-15 | 2013-08-22 | Kabushiki Kaisha Toshiba | Storage medium, reproducing method, and recording method |
-
2002
- 2002-03-12 JP JP2002066570A patent/JP3844704B2/en not_active Expired - Fee Related
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7876666B2 (en) | 2004-04-02 | 2011-01-25 | Kabushiki Kaisha Toshiba | Write-once information recording medium and coloring matter material therefor |
US20130215729A1 (en) * | 2005-03-15 | 2013-08-22 | Kabushiki Kaisha Toshiba | Storage medium, reproducing method, and recording method |
US20110141872A1 (en) * | 2005-04-14 | 2011-06-16 | Hideo Ando | Storage medium, reproducing method, and recording method |
US20070037095A1 (en) * | 2005-07-28 | 2007-02-15 | Noboru Sasa | Write-once-read-many optical disk having low-to-high recording property accommodating short wavelength recording |
US20110116353A1 (en) * | 2005-07-28 | 2011-05-19 | Noboru Sasa | Write-once-read-many optical disk having low-to-high recording property accommodating short wavelength recording |
US8846298B2 (en) * | 2005-07-28 | 2014-09-30 | Ricoh Company, Ltd. | Write-once-read-many optical disk having low-to-high recording property accommodating short wavelength recording |
US8859184B2 (en) * | 2005-07-28 | 2014-10-14 | Ricoh Company, Ltd. | Write-once-read-many optical disk having low-to-high recording property accommodating short wavelength recording |
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