Magneto-optic reproducing device using right and left circularly
polarized light
    62.
    发明授权
    Magneto-optic reproducing device using right and left circularly polarized light 失效
    使用右侧和左侧圆形偏振光的磁光复制装置

    公开(公告)号:US5202860A

    公开(公告)日:1993-04-13

    申请号:US664183

    申请日:1991-03-04

    IPC分类号: G11B11/105

    CPC分类号: G11B11/10545

    摘要: A reproducing optical device for a magneto-optical recording medium related to the present invention having light sources that emit linearly polarized lights towards a magneto-optical recording medium, polarization directions of the linearly polarized lights being mutually orthogonal. A quarter wavelength plate disposed between the recording medium and the light sources converts each of the linearly polarized lights into right and left circularly polarized lights respectively. Corresponding to recorded information, the recording medium has magnetized sections that are magnetized in a perpendicularly upward and downward direction with respect to a medium surface. Moreover, the recording medium displays the property of circular dichroism. When the right circularly polarized light and the left circularly polarized light are reflected off the recording medium, a first and a second photodetector generate a first and a second reproduced signal respectively, based on variation in reflected light intensity of each of the circularly polarized lights. This variation corresponds to the upward and the downward magnetization directions of the magnetized sections and is due to the circular dichroism effect. There is a phase difference of half a cycle between the first and the second reproduced signal and the signals vary inversely with respect to each other. Consequently, disk noise is cancelled by differentially amplifying the first and the second reproduced signal, and an SN ratio of a reproduced signal thereby can be improved.

    Optical memory having narrowed track pitch
    63.
    发明授权
    Optical memory having narrowed track pitch 失效
    具有窄轨道间距的光学存储器

    公开(公告)号:US5586109A

    公开(公告)日:1996-12-17

    申请号:US354457

    申请日:1994-12-12

    摘要: A transparent substrate of an optical memory is produced by injection molding using a stamper. Grooves and lands are alternately arranged on the optical memory, for tracking of light converged on the optical memory. The groove width is set in the range of 0.3 .mu.m to 0.4 .mu.m and the groove depth is set in the rage of 80 nm to 100 nm. A decrease in the width of a land at each edge is restrained to 0.2 .mu.m in maximum. With such dimensions, even when the track pitch is set to about 1.4 .mu.m, it is possible to obtain a track crossing signal with intensity sufficient for performing an access operation to a target track. Moreover, since the dimensions bring about an improved reflectance at a land, the optical memory achieves an improved C/N and recording density.

    摘要翻译: 通过使用压模的注射成型制造光学存储器的透明基板。 沟槽和焊盘交替布置在光学存储器上,用于跟踪会聚在光学存储器上的光。 槽宽度设定在0.3μm〜0.4μm的范围内,槽深度设定在80nm〜100nm的范围内。 每个边缘的陆地宽度减小最大限制在0.2亩。 利用这样的尺寸,即使当轨道间距设置为大约1.4μm时,也可以获得具有足以对目标轨道进行访问操作的强度的轨迹交叉信号。 此外,由于尺寸在陆地上产生改进的反射率,所以光学存储器实现了改进的C / N和记录密度。

    Magneto-optical disk
    64.
    发明授权
    Magneto-optical disk 失效
    磁光盘

    公开(公告)号:US5486395A

    公开(公告)日:1996-01-23

    申请号:US984350

    申请日:1992-12-02

    摘要: A magneto optical disk comprising: a circular substrate; a recording layer, formed on the substrate, for magneto-optical recording of information; a readout layer, formed between the substrate and the recording layer, for the reproduction of information recorded on the recording layer, wherein the readout layer has a Curie temperature which is higher than the Curie temperature of the recording layer, and exhibits in-plane magnetization at room temperature and a change from in-plane magnetization to perpendicular magnetization when its temperature rises over a certain temperature as a result of the application of a light beam, and wherein the magnetic compensation temperature is set such that it increases from the peripheral edge of the magneto-optical disk toward the center thereof. When the magneto-optical disk is used with a magneto-optical recording and reproducing device using a CAV system, it achieves high-density recording and the reproduction of signals with reduced noise, without causing the light beam control system to be complicated.

    摘要翻译: 一种磁光盘,包括:圆形衬底; 记录层,形成在基板上,用于磁光记录信息; 形成在基板和记录层之间的用于再现记录在记录层上的信息的读出层,其中读出层的居里温度高于记录层的居里温度,并且表现出面内磁化 在室温下由于施加光束而在其温度上升超过一定温度时从面内磁化变化到垂直磁化的变化,并且其中磁补偿温度被设定为使得其从外周边缘 磁光盘朝向其中心。 当磁光盘与使用CAV系统的磁光记录和再现装置一起使用时,可以实现高密度记录和降低噪声的信号的再现,而不会使光束控制系统复杂化。

    Magneto-optical recording medium
    66.
    发明授权
    Magneto-optical recording medium 失效
    磁光记录介质

    公开(公告)号:US5824426A

    公开(公告)日:1998-10-20

    申请号:US535967

    申请日:1995-09-28

    摘要: A magneto-optical recording medium includes a readout layer having in-plane magnetization at room temperature and in which a transition occurs from in-plane magnetization to a perpendicular magnetization when temperature rises, and a recording layer for storing information thereon magneto-optically. In the readout layer made of GdFeCo by adding Nd thereto, an amount of Nd to be added changes in a direction perpendicular to its film surface, and an amount of Nd is larger on a light incidence side than on the other side. As a result, even when a laser with a short wavelength is used, high density recording can be achieved as undesirable recording and reproducing operations due to a change in a magnetic interaction is prevented and also deterioration in quality of a reproducing signal is prevented.

    摘要翻译: 磁光记录介质包括在室温下具有面内磁化的读出层,并且其中当温度升高时从面内磁化转变为垂直磁化的过渡;以及用于在磁光上存储信息的记录层。 在通过添加Nd而由GdFeCo制成的读出层中,要添加的Nd的量在垂直于其膜表面的方向上变化,并且Nd的量在光入射侧比在另一侧更大。 结果,即使使用具有短波长的激光器,由于防止了磁相互作用的变化而导致由于不期望的记录和再现操作而导致高密度记录,并且也防止再现信号的质量劣化。

    Method of manufacturing a magneto-optical recording medium having a
readout layer with varying composition and curie temperature
    67.
    发明授权
    Method of manufacturing a magneto-optical recording medium having a readout layer with varying composition and curie temperature 失效
    具有具有不同组成和居里温度的读出层的磁光记录介质的制造方法

    公开(公告)号:US5764601A

    公开(公告)日:1998-06-09

    申请号:US685115

    申请日:1996-07-23

    摘要: A magneto-optical recording medium includes a readout layer has in-plane magnetization at room temperature and in which a transition occurs from in-plane magnetization to perpendicular magnetization when temperature thereof is raised, and a recording layer for recording thereon information. The composition of the readout layer varies in a direction perpendicular to the surface thereof, and in the readout layer, the Co density on the light incident side is higher than the Co density on the interface between the readout layer and the recording layer. Therefore, the Curie temperature on the reproducing light incident side of the readout layer is high and the the polar Kerr rotation angle in reproducing increases, thereby achieving improvements in a reproducing signal quality. On the other hand, since the Curie temperature on the interface is low, the shift of the threshold temperature at which a transition occurs from in-plane to perpendicular by the magnetic interaction between the layers can be suppressed, thereby achieving a high quality reproducing signal without changing the laser power required for reproduction very much.

    摘要翻译: 磁光记录介质包括读出层,其在室温下具有面内磁化,并且其温度升高时从面内磁化转变为垂直磁化,并且在其上记录信息的记录层。 读出层的组成在垂直于其表面的方向上变化,在读出层中,光入射侧的Co密度高于读出层与记录层之间的界面上的Co密度。 因此,读出层的再现光入射侧的居里温度高,再现时的极性克尔旋转角度增加,从而实现再现信号质量的改善。 另一方面,由于界面的居里温度低,所以可以抑制通过层之间的磁相互作用从平面到垂直发生的阈值温度的偏移,从而实现高质量再现信号 而不需要更改再生所需的激光功率。

    Optical memory having narrowed track pitch
    68.
    发明授权
    Optical memory having narrowed track pitch 失效
    具有窄轨道间距的光学存储器

    公开(公告)号:US5676854A

    公开(公告)日:1997-10-14

    申请号:US688852

    申请日:1996-08-01

    摘要: A transparent substrate of an optical memory is produced by injection molding using a stamper. Grooves and lands are alternately arranged on the optical memory, for tracking of light converged on the optical memory. The groove width is set in the range of 0.3 .mu.m to 0.4 .mu.m and the groove depth is set in the rage of 80 nm to 100 nm. A decrease in the width of a land at each edge is restrained to 0.2 .mu.m in maximum. With such dimensions, even when the track pitch is set to about 1.4 .mu.m, it is possible to obtain a track crossing signal with intensity sufficient for performing an access operation to a target track. Moreover, since the dimensions bring about an improved reflectance at a land, the optical memory achieves an improved C/N and recording density.

    摘要翻译: 通过使用压模的注射成型制造光学存储器的透明基板。 槽和焊盘交替布置在光学存储器上,用于跟踪会聚在光学存储器上的光。 槽宽度设定在0.3μm〜0.4μm的范围内,槽深度设定在80nm〜100nm的范围内。 每个边缘的陆地宽度减小最大限制在0.2亩。 利用这样的尺寸,即使当轨道间距设置为大约1.4μm时,也可以获得具有足以对目标轨道进行访问操作的强度的轨迹交叉信号。 此外,由于尺寸在陆地上产生改进的反射率,所以光学存储器实现了改进的C / N和记录密度。

    Magnetic recording medium and information recording-reproduction method
using the same
    69.
    发明授权
    Magnetic recording medium and information recording-reproduction method using the same 失效
    磁记录介质和使用该磁记录介质的信息记录再现方法

    公开(公告)号:US5656385A

    公开(公告)日:1997-08-12

    申请号:US88608

    申请日:1993-07-07

    摘要: A magnetic recording medium having a recording layer made up of a ferrimagnetic material whose compensation temperature is included within room temperatures and an information recording-reproduction method using the magnetic recording medium. During recording, while a light beam is projected on the recording layer so as to raise the temperature of a recording portion, information is recorded by applying a signal magnetic field from a magnetic head. During reproduction, while a light beam is projected on a reproducing portion of the recording layer so as to raise the temperature thereof, information is reproduced by detecting leakage flux from the reproducing portion by the magnetic head. Thus, during reproduction, no magnetic flux is generated from other portions of the recording layer not irradiated by the light beam. With the arrangement, crosstalk due to leakage flux from adjoining tracks not irradiated by the optical beam can be eliminated. Therefore, track pitches can be made narrower so as to increase recording density of the magnetic recording medium. Further, since crosstalk from adjoining tracks is eliminated, a high S/N can be achieved.

    摘要翻译: 一种磁记录介质,其具有由补偿温度包括在室温内的铁氧体材料制成的记录层和使用该磁记录介质的信息记录再现方法。 在记录期间,当光束投射在记录层上以提高记录部分的温度时,通过施加来自磁头的信号磁场来记录信息。 在再现期间,当光束投射在记录层的再现部分上以升高其温度时,通过由磁头检测来自再现部分的漏磁通来再现信息。 因此,在再现期间,不会由不被光束照射的记录层的其它部分产生磁通量。 利用该布置,可以消除由于未被光束照射的相邻轨道的漏磁通引起的串扰。 因此,可以使轨道间距更窄,以提高磁记录介质的记录密度。 此外,由于消除了来自相邻轨道的串扰,可以实现高S / N。

    Magneto optical memory device
    70.
    发明授权
    Magneto optical memory device 失效
    磁光存储器件

    公开(公告)号:US5631096A

    公开(公告)日:1997-05-20

    申请号:US400464

    申请日:1995-03-07

    IPC分类号: G11B11/10 G11B11/105 G11B5/66

    摘要: A magneto-optical memory device is provided with a base whereon a first magnetic film which exhibits in-plane magnetization at room temperature and exhibits perpendicular magnetization at above room temperature, a second magnetic film having its Curie temperature above room temperature; and a third magnetic film having its Curie temperature set above the Curie temperature of the second magnetic film, which exhibits perpendicular magnetization in a temperature range between room temperature and Curie temperature are laminated in this order. When recording, the temperature of the third magnetic film is raised to the vicinity of its Curie temperature, and information is recorded thereon by an external magnetic field. As the magnetization of the second magnetic film having a temperature rise above its Curie temperature disappears, an exchange coupling force is not exerted between the first magnetic film and the third magnetic film. In the above arrangement, since the effect from the magnetization of the first magnetic film can be avoided, information can be recorded on the third magnetic film by a small external magnetic field, thereby permitting a reduction in electric power consumption and in the size of the apparatus.

    摘要翻译: 磁光存储器件设置有第一磁性膜的基底,第一磁性膜在室温下表现出平面内的磁化强度,并且在室温以上表现出垂直的磁化强度,第二磁性膜的居里温度高于室温; 并且将其居里温度设定在高于室温和居里温度之间的温度范围内的垂直磁化强度的第二磁性膜的居里温度的第三磁性膜依次层叠。 当记录时,第三磁性膜的温度升高到其居里温度附近,并且通过外部磁场在其上记录信息。 随着具有高于其居里温度的温度升高的第二磁性膜的磁化消失,在第一磁性膜和第三磁性膜之间不产生交换耦合力。 在上述结构中,由于可以避免第一磁性膜的磁化的影响,所以可以通过小的外部磁场将信息记录在第三磁性膜上,从而能够降低电力消耗和 仪器。