CN1758353A - 光记录媒体 - Google Patents
光记录媒体 Download PDFInfo
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- CN1758353A CN1758353A CN200510099495.9A CN200510099495A CN1758353A CN 1758353 A CN1758353 A CN 1758353A CN 200510099495 A CN200510099495 A CN 200510099495A CN 1758353 A CN1758353 A CN 1758353A
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- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/241—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material
- G11B7/242—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers
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- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/2403—Layers; Shape, structure or physical properties thereof
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- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
- G11B7/2403—Layers; Shape, structure or physical properties thereof
- G11B7/24035—Recording layers
- G11B7/24038—Multiple laminated recording layers
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- G11B2007/25705—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of layers having properties involved in recording or reproduction, e.g. optical interference layers or sensitising layers or dielectric layers, which are protecting the recording layers consisting essentially of inorganic materials
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- G11B2007/25705—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of layers having properties involved in recording or reproduction, e.g. optical interference layers or sensitising layers or dielectric layers, which are protecting the recording layers consisting essentially of inorganic materials
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- G11B7/247—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising organic materials only containing dyes methine or polymethine dyes
- G11B7/2472—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of recording layers comprising organic materials only containing dyes methine or polymethine dyes cyanine
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- G11B7/24—Record carriers characterised by shape, structure or physical properties, or by the selection of the material
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- G11B7/253—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates
- G11B7/2533—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates comprising resins
- G11B7/2534—Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the selection of the material of layers other than recording layers of substrates comprising resins polycarbonates [PC]
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Abstract
本发明提供一种多层光记录媒体(10),其在基板(12)和透光性覆盖层(14)之间层积L0层(16)、L1层(18)、L2层(20)、L3层(22)的四层记录层和各记录层间的透光性隔离层(17、19、21)而成,所述L2层(20)为相对再现用激光的入射角反射率具有负的依赖性的结构,从各记录层的结构和串扰的关系中可以更高效地减小串扰。
Description
技术领域
本发明涉及光记录媒体,尤其涉及具有三层以上的记录层的光记录媒体。
背景技术
作为记录数字数据用的记录媒体,广泛使用了CD(小型盘)或DVD(数字通用盘)等的光记录媒体。在这种光记录媒体中,为了增大存储容量,有信息记录层为多层结构的多层光记录媒体。这种多层光记录媒体中,各记录层为以透光性隔离层(spacer)为间隔来层积的结构。
在上述这种多层结构的光记录媒体中,在再现某一记录层的记录标记时,存在来自其他记录层的反射光,在该反射光量或记录层间的距离因某种原因改变了的情况下,有该改变(下面为串扰改变)作为噪声叠加在再现信号上的问题。
作为降低这种层间串扰的影响的对策,例如日本特开2004-213720号公报中所记载的,提出了在每个记录层上使记录层间距离不均匀的光记录媒体。
发明内容
本发明的目的是提供一种从多层光记录媒体的记录层的反射率和串扰的关系中可以更有效地降低层间串扰的光记录媒体。
本发明人锐意研究的结果发现了在透光性隔离层的整体厚度为5μm以上时,三次串扰构成层间串扰的大部分,并且,其大致完全由共焦点串扰引起。另外,实际的4层光记录媒体具有50μm左右的透光性隔离层,发现了由层间串扰造成的影响大致完全由共焦点的三次串扰引起。
这里,说明上述的“三次串扰”和“共焦点串扰”。
如图18A所示,例如,例如在基板12和透光性覆盖层14之间具有L0层16、L1层18、L2层20、L3层22的四层记录层的光记录媒体1中,例如在再现L0层16时,向透光性覆盖层14入射的再现光中,仅通过L0层16反射而射出到光记录媒体外部的成份是信号光。另一方面,还存在通过L1层18、L2层20、L3层22的其中一层仅反射一次而向光记录媒体外部射出的成份,其是所谓的串扰光,但是为了与后述的多重反射成份相区别,称作“1次串扰(光)”。由于多层光记录媒体为层积了具有有限发射率的记录层的结构,所以存在在这些记录层间反射了几次的多重反射成份。
实际上向记录媒体外部射出的多重反射成份,仅仅是经历了记录层的奇数次反射的光,其中反射次数最少的光经历了三次反射。将其称作“三次串扰(光)”。
图18A是三次串扰的一例,是以L2层→L3层→L1层的顺序来进行反射的成份。除此之外,虽然还存在经历了5次、7次、…等更多次反射的成份,但是由于每次反射时,光的强度衰减,所以可以忽略反射了5次以上的多重反射成份。图18A中用虚线表示的是信号光的光路,但是用粗线表示的三次串扰光向着与信号光完全相同的光路射出。虽然通常一次或三次串扰光射出到与信号光不同的光路上,但是在记录层间的间隔特殊的情况下,存在如图18A所示,射出到与信号光相同的光路上的串扰。将这种成份特别称作“共焦点串扰(光)”。
图18A~图18C中表示了具有某个特定的入射角的一条光线,但是实际上,在一定的入射角范围内存在多条光线,这些光线集中到一点上的点是焦点。共焦点串扰光尽管在光记录媒体内部聚光在与信号光不同的点上,但是在光记录媒体外部恰好作为与信号光为同一焦点的发射球面波工作。
本发明通过降低上述共焦点的三次串扰,而可有效降低整体的串扰的光记录媒体来实现上述目的。
即,可以通过下面的本发明来实现上述目的。
(1)一种光记录媒体,在基板和透光性覆盖层之间,从基板侧开始至少层积L0层、L1层、L2层的三层记录层和各记录层间的透光性隔离层,其特征在于:除去所述L0层的记录层中至少一层的记录层为相对再现用激光的入射角,反射率具有负的依赖性的结构。
(2)如(1)所述的光记录媒体,其特征在于:反射率相对入射角具有负的依赖性的所述记录层由记录膜和从厚度方向两侧夹着该记录膜的透光性保护膜构成,所述记录膜的折射率比所述透光性保护膜的折射率大。
(3)如(2)所述的光记录媒体,其特征在于:在所述记录膜的膜厚t为0<t≤5nm时,所述透光性保护膜的折射率为2.1以上2.5以下。
(4)如(2)所述的光记录媒体,其特征在于:在所述记录膜的膜厚t为5<t≤30nm时,所述透光性保护膜的折射率为1.9以上2.35以下。
(5)如(1)-(4)中的任一项所述的光记录媒体,其特征在于:反射率相对入射角具有负的依赖性的所述记录层包含膜厚t为5<t≤30nm的记录膜。
(6)如(1)-(5)中的任一项所述的光记录媒体,其特征在于:反射率相对入射角具有负的依赖性的所述记录层的相对反射率Rth在该记录层的光束点直径位置上为0.9以下,其中所述相对反射率Rth是入射角θ下的反射率相对再现用激光在以入射角0度入射时的反射率的比。
(7)如(1)-(5)中的任一项所述的光记录媒体,其特征在于:反射率相对入射角具有负的依赖性的所述记录层的相对反射率Rth在该记录层的光束点直径位置上为0.85以下,其中所述相对反射率Rth是入射角θ下的反射率相对再现用激光在以入射角0度入射时的反射率的比。
另外,上述θ在n为透光性隔离层的折射率或透光性覆盖层的折射率、NA为再现用激光光学***的物镜的开口数时,由θ=sin-1(NA/n)表示。
本发明通过构成为在基板和透光性覆盖层之间,从基板侧开始至少层积了L0层、L1层、L2层三层的记录层和各记录层间的透光性隔离层的光记录媒体中,使去除所述L0层的记录层中至少一层的记录层相对再现用激光的入射角反射率具有负的依赖性,从而使在散焦状态下向反射面入射的串扰光利用其入射角具有分布的情况,使反射率降低,由此,实现了可大幅度减小层间串扰的影响的效果。
附图说明
图1是表示本发明的实施例的光记录媒体的局部断面立体图;
图2是模式放大表示该实施例的光记录媒体的主要部分的截面图;
图3是模式放大表示所述光记录媒体的L2层的膜结构的截面图;
图4A~图4D是在一般的4层光记录媒体中,模式表示再现L0层时的信号光和串扰光的光路的截面图;
图5A~图5D是模式表示了对于图4A的信号光和图4B的串扰光的全体的反射入射到反射面的光路的截面图;
图6是模式放大表示向该实施例的光记录媒体L0层的再现用激光束的入射状态的截面图;
图7是表示焦平面上的光束点直径的半径和再现用激光束的强度分布状态的曲线图;
图8是表示再现用激光束的向作为反射面的记录层的入射角θ和反射率的关系的曲线图;
图9是表示记录层中的相对入射角为0度的再现用激光束的反射率的光束点内的相对反射率和对于焦平面的光束的相对强度之间的关系的曲线图;
图10是表示再现多层光记录媒体时的一般的光学***的光学配置图;
图11是表示所再现的L0层和作为反射层的记录层的关系和反射层位置上的再现用激光束的强度分布的状态的曲线图;
图12是表示记录层的膜厚和对于再现用激光束的反射、透过、吸收率的关系的曲线图;
图13是表示再现用激光束的入射角和记录层的反射·投射·吸收率的关系的曲线图;
图14是将图13的反射率仅放大表示了反射率为0~0.2的范围的部分的曲线图;
图15是按每个记录层的膜厚来表示向记录层的入射角度为0度时的反射率和入射角度为33度时的反射率的比与保护膜的折射率的关系的曲线图;
图16是按每个保护膜的折射率来表示再现用激光束的入射角为0度时的反射率和相对反射率的关系的曲线图;
图17是表示对于记录层的膜厚的积分相对强度和入射角为0度时的反射率的关系的曲线图;
图18A~图18C是现有的4层光记录媒体的共焦点串扰光的状态的截面图。
具体实施方式
光记录媒体在基板和透光性覆盖层(下面为覆盖层)之间从基板侧开始,层积L0层、L1层、L2层、L3层的记录层和各记录层之间的透光性隔离层(下面为隔离层),通过使所述L2层的记录膜的膜厚t为0<t≤30nm,来实现上述目的。
接着,说明图1和图2所示的本发明的实施例。
该实施例的光记录媒体10构成为在基板12和覆盖层14之间层积L0层16、L1层18、L2层20、L3层22的4层记录层和各记录层间的隔离层17、19、21。
所述L2层如后所详细描述的,为相对再现用激光的入射角,反射率具有负的依赖性的结构。
详细地,如图3所示,所述L2层20由记录膜20A、从厚度方向两侧夹持该记录膜20A的透光性保护膜(下面为保护膜)24A、24B构成,该记录膜20A的折射率比保护膜24A、24B的折射率大,进一步,记录膜20A的膜厚t为0<t≤30nm,保护膜24A、24B的折射率在0<t≤5nm时为2.1以上2.5以下,在5<t≤30nm时为1.9以上2.35以下。
若如上这样构成光记录媒体10,则在L0层16的再现时,通过L2层20反射形成的串扰光的强度与信号光相比大大降低,由此,可以减小由串扰光造成的影响。
下面,参照附图,来说明可降低串扰光的影响的作用机理。
首先,如图2所示,在如所述光记录媒体10那样的4层光记录媒体中,在再现L0层时,其信号光的光路如图4A所示那样。
这时产生的相对所述信号光为共焦点的串扰光仅为图4B、图4C、图4D所示的三种图案(其中,设各记录层间的间隔完全相等)。
由于图4B~图4D的串扰光与图4A的信号光共焦点,所以表面看将L0层16作为焦平面入射、反射,但是相对于信号光在L0层16中聚光,串扰光在没有聚光的散焦状态下入射、反射。
图5A~图5D表示对于上述图4A所示的信号光和图4B所示的串扰光的全部反射入射到反射面的光路。
从该图中可以看出相对于图5A中信号光的反射面和焦平面一致,图5B所示的串扰光中,L2层20成为反射面,L0层16为焦平面,在散焦状态下进行反射。
图2放大表示了串扰光在L2层(反射面)20附近的光路。图2中,实线表示实际的光路,双点划线表示从所述实际的光路向L2层20和L0层16之间的延长线(虚拟光路)。另外,图6放大表示信号光在L0层(反射面)16附近的光路。
如图6所示,对于信号光,入射光的焦平面和反射面同时为L0层16,两者一致。图2、图6的虚线表示几何光学的光路,但是在焦平面附近因光的波动性实际的光路和几何光学光路不一致,在焦平面上具有称作衍射界限的有限的光点大小(Ds)。
在图6所示的信号光的情况下,再现用激光通过物镜来聚焦,并在接近于球面波的状态下入射到光记录媒体中,但是在焦平面附近可以看作波面平坦的平面波。这里,由于光记录媒体的记录层一般具有层积了多个薄膜的多层膜结构,并将如上所述的入射光看作平面波,所以光束点内的光线群显示大致相同的光学特性(反射·吸收·透过率)。
另一方面,在串扰光的情况下,如图2所示,由于在散焦状态下入射到作为反射面的L2层20,所以在与作为焦平面的L0层16分离的反射面(L2层20)中,几何光学的光路一致,入射角上产生分布。
但是,实际的光路和几何光学光路显著不同的是焦平面到波长左右的距离,通常由于多层光记录媒体的各记录层间距离为10~20μm左右,所以与波长相比充分大,认为串扰光在反射面上取几何光学的光路。
即,串扰光为带着图2所示的入射角分布入射到焦平面上,且成为从此反射的光路,与此相对,如前所述,信号光在焦平面附近可以看作是平面波,入射角没有分布。因此,若作为串扰光的反射面的L2层20的反射率相对入射角具有负的依赖性,则串扰光与信号光相比强度大幅度降低,可以抑制其影响。
接着,进一步详细说明如上所述的通过对反射层的反射率提供负的入射角依赖性,而可降低串扰光的强度的理由。
如图2所示,设串扰光在焦平面上的光束点直径为Ds,焦平面(L0层16)和反射面(L2层20)之间的距离为z,反射面上的光束点直径为Dz、反射面上的入射角为θ,进一步,例如若设再现用激光的波长λ=405nm、物镜的开口数NA=0.85、构成光记录媒体10的覆盖层14、隔离层17、19、21为紫外线硬化树脂,其折射率n=1.56,则在z=10μm时Dz=13.00μm。再现用激光束的强度分布为高斯分布,为中心强度的1/e2的光束直径与Dz一致,入射的再现用激光束的强度分布如图11所示。
正确描绘了再现用激光束的强度分布的是图7,相当于光束点直径Dz=13.00μm的位置上的强度为中心强度的1/e2。反射面上的半径r和入射角θ之间有r=Ztanθ的关系。这里,若L2层20的反射率如图8所示,具有相对入射角的负的依赖性,则对于图2所示的光路,L2层20的反射率比垂直入射的情况下低,所以降低了串扰。
即,若相对再现用激光束的垂直入射(入射角=0度),有限的入射角(向焦平面收敛的角度为2θ)的反射率小,则串扰光的相对光量减小,降低了串扰。
接着,说明如上所述的定量计算由记录层的反射率的入射角依赖性为负带来的串扰光的降低效果的过程。
首先,如图8所示,假定反射率来定量计算串扰光的降低效果。这里,图7、图8中,粗线相当于强度1/e2的轨迹,即,所谓的光束点直径。设置相对的反射率(用垂直入射时的反射率来标准化),使其相对入射角θ线性减小,且相当于光束点直径的角度为Rth。
图8是相对反射率Rth=0.5的情况,设图7所示的强度分布为I(r)、s;作为焦平面和反射面间距离,图8中的相对反射率为R[θ(r)]、θ(r)=tan-1(r/s)时,串扰光的相对强度为
相对强度=∫∞ 0I(r)R[θ(r)]×2πrdr…(1)
图9表示对于表现上述反射率的入射角依赖性的参数Rth(相对反射率),通过上述(1)式算出的相对串扰强度。这里,表示了在相对串扰强度用信号强度,即反射率为1而与入射角无关的情况下的计算值来比较后的值。
在图4B、图4C所示的串扰光中,由于在散焦状态下经历了3次反射,所以作为向光记录媒体外射出的串扰强度为通过上述(1)式计算出的值的三次方。同样,由于图4D所示的串扰光的强度中,L2层20上的反射为聚焦状态,所以散焦状态的反射为两次,成为通过所述(1)式计算出的值的二次方。由于图4B~图4D所示的串扰相对串扰整体的作用效果不相等,所以在考虑各自的作用效果方面,图9中用粗线表示了平均了图4B~图4D的相对强度后的值。
从图9中,若假设可识别的串扰降低效果为10%,则相对反射率最好为90%以下,进一步为了使串扰降低效果为20%以上,相对反射率为85%以下。
接着,说明如上所述的使反射率相对再现用激光束的入射角具有负的依赖性用的记录层的具体结构。
首先,作为串扰光的反射面的记录层(L2层20)的记录膜20A若如所述图3放大所示的,从厚度方向两侧通过保护膜24A、24B夹持时,设置为记录膜20A的折射率n2比该保护膜24A、24B的折射率n21大。
所述保护膜24A、24B的折射率n21在所述记录膜20A的膜厚t为0<t≤5nm时,为2.1以上2.5以下,在5<t≤30nm时,为1.9以上2.35以下。
进一步,设定为所述L2层20的相对再现用激光以入射角0度入射时的反射率的入射角θ的相对反射率Rth在该L2层20的光束点直径位置上为0.9以下,更好为0.85以下。
以下,说明上述条件的理由。
在图10所示的光学***中,考虑经物镜28将再现用激光束照射到光记录媒体10,再现L0层16时的L2层20的反射率的角度依赖性。
若表示图2的L0层~L2层附近部分上的光路和入射光的强度分布,则为如图11所示。
对于这种光记录媒体,作为基于Blu-ray(商标)标准的光学参数,在设再现用激光束的波长为405nm、物镜的开口数NA=0.85、覆盖层和隔离层的折射率n0=ns=1.56时,再现用激光束的最大入射角在空气中为θ58.2,覆盖层和隔离层内部中θmax33.0度。
所述图3所示的L2层的结构根据实际要求的记录特性,来决定膜数、膜材料、膜厚等,这里使用简单的三层结构来进行说明。
所述保护膜24A、24B由在温度变化上有耐性的电介质材料构成,例如使用硫化锌、氧化硅或他们的混合物,作为记录层,使用例如由锗、锑、碲代表的相变化记录材料、花青色素等的有机记录材料、光聚合物、光折变材料等。这里,使用可进行一次写入记录的氧化铋(复数折射率n2=2.45-0.28i),另外,在覆盖层和隔离层上使用紫外线硬化树脂,在基板上使用聚碳酸酯材料或玻璃材料等。
接着,对于图3的三层结构,使所述保护膜24A、24B的折射率n21在1.9~2.5上变化,记录膜20A的膜厚t在0<t<500nm变化,使入射角θ在0<θ<90度下变化,来计算反射率·透过率和吸收率。这里,设入射角θ表示覆盖层内的角度,覆盖层表面、L2层20和基板里面的反射光不产生作用。
首先,将保护膜的折射率设为n21=2.2、入射角设为0度,使记录膜的膜厚变化时的反射·透过·吸收率的变化如图12所示。这里,记录层除去L0层外,需要透过记录再现该基板侧的记录层的光束,所以一般要求50%以上的透过率。因此,从图12中可以看出作为记录膜的膜厚最好在80nm以下。
图13表示设记录膜20A的膜厚为15nm时、计算了使再现用激光束的入射角θ变化时的反射·透过·吸收率的情况。另外,图14放大表示了图13的反射率从0.00到0.20的部分。
图13、图14中,对于有限的入射角(θ>0),反射·透过·吸收率根据再现用激光束的偏光状态不同,所以重叠表示了对两个偏光状态的结果。另外,在这些图中,细线表示s偏光(电场矢量为垂直于图11的纸面的方向),粗线表示p偏光,另外,虚线表示这些的算术平均值。由于实际的光记录***的光电拾光器使用接近于圆偏光的状态的激光束,所以所述虚线表示实际情况。
这里,为了使说明简单,作为串扰降低效果的参考,考虑θ=33度时的反射率和θ=0度的反射率的比。
例如,在图14的例子中,由于对于θ=0度的反射率为R(0)=0.1109,对于θ=33度的反射率为R(33)=0.0539,所以相对反射率Rth=R(33)/R(0)=0.0539/0.1109=0.486。在图13的例子中,在0<θ≤33的范围内反射率单调减小。
接着,图15表示使所述保护膜24A、24B的折射率和记录层的膜厚变化时的所述相对反射率Rth的变化。
从该图15中可以看出对于其中一个膜厚,有折射率越小,相对反射率Rth越小的倾向。尤其,在记录层的膜厚为5nm时,保护膜的折射率为2.1以上2.5以下的情况下,相对反射率Rth小于1.0,在记录膜的膜厚为10、15nm时,保护膜的折射率为1.9以上2.4以下,在记录膜的膜厚为20nm时,保护膜的折射率为1.9以上2.45以下,相对反射率Rth单调增加。图16表示了根据与图15中所用的相同的数据,对θ=0度的反射率的保护膜的每个折射率的相对反射率Rth。
从该图16中可以看出在保护膜的折射率比记录层的折射率(2.45)小的区域中,对于大范围的反射率的范围,相对反射率Rth小于1.0,尤其,在记录层的反射率为12%以下的情况下,相对反射率Rth小于0.5,可以得到更大的串扰降低效果。
另外,认为在保护膜的折射率比记录层的折射率大的区域中,相对反射率全部超过1,串扰增加了。
不仅考虑入射角θ=0度和33度,还考虑其之间的反射率、再现光束的强度分布,图17表示计算了综合的反射强度的结果。
这里,再现用激光束强度是相对图11的符号r的高斯分布,光束强度为最大强度(光轴上的强度)的1/e2的位置与定义物镜NA的光路一致。
如图13所示,所计算的反射率为入射角θ的函数,高斯分布也通过r=ttanθ的关系转换为θ的函数,除了乘以反射率之外,还在θ=0~90度的范围内,执行数值积分,来求出反射光强度。
作为比较的对象,没有反射率的角度依赖性的情况是合适的,所以将反射率假定为一定值(θ=0度的情况下的反射率的值),而与入射角无关的情况下也执行同样的数值积分,将在该值下比较了反射光强度的值作为积分相对强度Rrel,由图17的粗线表示,在θ=0度的情况下的反射率用细线表示。虽然实际上所要求的反射率的值根据***不同,但是在记录膜的膜厚t=0~30nm的范围内,可以兼顾4~14%的大范围的反射率值和比1小的积分相对强度值(降低串扰)。
另外,在上述实施例中,光记录媒体具有4层的记录层,但是本发明并不限于此,适用于记录层为3层以上的情况。
另外,在同一实施例中,L2层为相对再现用激光的入射角,反射率具有负的依赖性的结构,但是也可以是除了L0层的其他记录层中的至少任意一个相对再现用激光的入射角,反射率具有负的依赖性的结构。
Claims (9)
1.一种光记录媒体,在基板和透光性覆盖层之间,从基板侧开始至少层积L0层、L1层、L2层的三层的记录层和各记录层间的透光性隔离层,其特征在于:
除了所述L0层的记录层中的至少一层记录层相对再现用激光的入射角,反射率具有负的依赖性。
2.根据权利要求1所述的光记录媒体,其特征在于:反射率相对入射角具有负的依赖性的所述记录层由记录膜和从厚度方向两侧夹持该记录膜的透光性保护膜构成,所述记录膜的折射率比所述透光性保护膜的折射率大。
3.根据权利要求2所述的光记录媒体,其特征在于:在所述记录膜的膜厚t为0<t≤5nm时,所述透光性保护膜的折射率为2.1以上2.5以下。
4.根据权利要求2所述的光记录媒体,其特征在于:在所述记录膜的膜厚t为5<t≤30nm时,所述透光性保护膜的折射率为1.9以上2.35以下。
5.根据权利要求1~4中任一项所述的光记录媒体,其特征在于:反射率相对入射角具有负的依赖性的所述记录层包含膜厚t为0<t≤30nm的记录膜。
6.根据权利要求1~4中任一项所述的光记录媒体,其特征在于:反射率相对入射角具有负的依赖性的所述记录层的相对反射率Rth在该记录层的光束点直径位置为0.9以下,所述相对反射率Rth是入射角θ下的反射率相对再现用激光以入射角0度入射时的反射率之比。
7.根据权利要求5所述的光记录媒体,其特征在于:反射率相对入射角具有负的依赖性的所述记录层的相对反射率Rth在该记录层的光束点直径位置为0.9以下,所述相对反射率Rth是入射角θ下的反射率相对再现用激光以入射角0度入射时的反射率之比。
8.根据权利要求1~4中任一项所述的光记录媒体,其特征在于:反射率相对入射角具有负的依赖性的所述记录层的相对反射率Rth在该记录层的光束点直径位置为0.85以下,所述相对反射率Rth是入射角θ下的反射率相对再现用激光以入射角0度入射时的反射率之比。
9.根据权利要求5所述的光记录媒体,其特征在于:反射率相对入射角具有负的依赖性的所述记录层的相对反射率Rth在该记录层的光束点直径位置上为0.85以下,所述相对反射率Rth是入射角θ下的反射率相对再现用激光以入射角0度入射时的反射率之比。
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JP2004266060A JP2006079795A (ja) | 2004-09-13 | 2004-09-13 | 光記録媒体 |
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Cited By (2)
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CN102682805A (zh) * | 2011-02-09 | 2012-09-19 | Tdk股份有限公司 | 多层光记录介质 |
CN102782757A (zh) * | 2010-03-10 | 2012-11-14 | 富士胶片株式会社 | 光记录盘和用于在光记录盘上记录或读出数据的方法 |
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US20080170484A1 (en) * | 2007-01-15 | 2008-07-17 | Tdk Corporation | Optical recording medium |
US20080170485A1 (en) * | 2007-01-15 | 2008-07-17 | Tdk Corporation | Optical recording medium |
JP4803138B2 (ja) * | 2007-05-18 | 2011-10-26 | Tdk株式会社 | 光記録媒体及びその再生方法 |
CN113053085B (zh) * | 2021-02-04 | 2022-06-03 | 北京戴纳实验科技有限公司 | 一种医院冰箱监管*** |
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US5748598A (en) | 1995-12-22 | 1998-05-05 | Massachusetts Institute Of Technology | Apparatus and methods for reading multilayer storage media using short coherence length sources |
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JP3558306B2 (ja) * | 1994-07-26 | 2004-08-25 | パイオニア株式会社 | 多層記録ディスク及びこれを用いた記録/再生システム |
US5764619A (en) * | 1995-04-07 | 1998-06-09 | Matsushita Electric Industrial Co., Ltd. | Optical recording medium having two separate recording layers |
US5669995A (en) | 1996-01-29 | 1997-09-23 | Hong; Gilbert H. | Method for writing and reading data on a multi-layer recordable interferometric optical disc and method for fabricating such |
US5972457A (en) * | 1996-12-03 | 1999-10-26 | Mitsubishi Chemical Corporation | Optical recording medium |
US6353592B1 (en) * | 1997-06-27 | 2002-03-05 | Sony Corporation | Optical recording medium and optical disk device |
JP2000182274A (ja) * | 1998-10-06 | 2000-06-30 | Tdk Corp | 光記録媒体および光記録方法 |
JP2002025098A (ja) | 2000-07-07 | 2002-01-25 | Pioneer Electronic Corp | ピックアップ装置 |
JP2001155380A (ja) * | 2000-10-27 | 2001-06-08 | Victor Co Of Japan Ltd | 光記録媒体 |
JP2002279692A (ja) * | 2001-03-21 | 2002-09-27 | Victor Co Of Japan Ltd | 光情報記録媒体 |
JP2003208733A (ja) * | 2001-11-08 | 2003-07-25 | Konica Corp | 光記録媒体及び情報の記録読み出し方法 |
JP3699926B2 (ja) | 2001-12-03 | 2005-09-28 | 株式会社東芝 | 光ディスク記録装置、光ディスク記録方法、光ディスク再生装置、光ディスク |
JP2004013947A (ja) * | 2002-06-04 | 2004-01-15 | Victor Co Of Japan Ltd | 情報記録担体、再生装置、記録装置、記録再生装置、再生方法、記録方法及び記録再生方法 |
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JP4215497B2 (ja) | 2002-12-27 | 2009-01-28 | Tdk株式会社 | 光記録媒体 |
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JP4108553B2 (ja) | 2003-07-01 | 2008-06-25 | 株式会社日立製作所 | 光情報記録媒体及び光情報記録装置 |
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CN102782757A (zh) * | 2010-03-10 | 2012-11-14 | 富士胶片株式会社 | 光记录盘和用于在光记录盘上记录或读出数据的方法 |
CN102782757B (zh) * | 2010-03-10 | 2016-01-20 | 富士胶片株式会社 | 光记录盘和用于在光记录盘上记录或读出数据的方法 |
CN102682805A (zh) * | 2011-02-09 | 2012-09-19 | Tdk股份有限公司 | 多层光记录介质 |
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US7675838B2 (en) | 2010-03-09 |
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US20060077877A1 (en) | 2006-04-13 |
CN100536003C (zh) | 2009-09-02 |
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