公开(公告)号：US06198704B1

公开(公告)日：2001-03-06

申请号：US09496654

申请日：2000-02-03

申请人： Yoshihito Fukushima ,  Jun Shimizu ,  Takeshi Gouko ,  Atsushi Takeuchi ,  Yuko Nakamura ,  Manabu Iwai

发明人： Yoshihito Fukushima ,  Jun Shimizu ,  Takeshi Gouko ,  Atsushi Takeuchi ,  Yuko Nakamura ,  Manabu Iwai

IPC分类号： G11B1100

CPC分类号： G11B11/10593 ,  G11B11/10515

摘要： A magneto-optical recording medium from which data is read by using a Kerr effect and which is capable of preventing signal imbalance caused from change in birefringence even in a system in which the amplitude of a reproduced signal is small and the spatial frequency of a shortest record signal train of the magneto-optical recording medium is 1.1×NA/&lgr;(line/m) or higher. The photoelastic coefficient of a substrate of the magneto-optical recording medium is 50×10−13 cm2/dyne or smaller. The vertical birefringence of the substrate is 250×10−6 or smaller, the coefficient of water absorption of the same is 0.2 wt % or lower and the thermal coefficient of expansion of the same is 6.5×10−5 cm/cm·° C. or lower.

摘要翻译： 一种磁光记录介质，通过使用克尔效应从中读取数据，并且即使在再现信号的幅度小，空间频率最短的系统中也能够防止由双折射变化引起的信号失衡 磁光记录介质的记录信号序列为1.1xNA / lambd（行/ m）以上。 磁光记录介质的基板的光弹性系数为50×10 13 cm 2 / dyne以下。 基板的垂直双折射率为250×10 -6以下，其吸水系数为0.2重量％以下，其热膨胀系数为6.5×10 -5 cm / cm。℃以下 。

公开(公告)号：US06487164B1

公开(公告)日：2002-11-26

申请号：US09585305

申请日：2000-06-01

申请人： Sohmei Endoh ,  Manabu Iwai ,  Katsuhiko Ohtomo ,  Tomiji Tanaka ,  Hiroshi Nakayama ,  Masayoshi Kanno ,  Masataka Shinoda

发明人： Sohmei Endoh ,  Manabu Iwai ,  Katsuhiko Ohtomo ,  Tomiji Tanaka ,  Hiroshi Nakayama ,  Masayoshi Kanno ,  Masataka Shinoda

IPC分类号： G11B724

CPC分类号： G11B7/24085 ,  G11B7/007 ,  G11B7/0938 ,  G11B7/261 ,  G11B7/263 ,  G11B11/10578 ,  G11B11/10582 ,  G11B11/10584 ,  G11B11/10597

摘要： In an optical recording medium having a writable area in which grooves are formed along recording tracks and a read-only area in which pits are formed along the recording tracks, sufficient levels of signals required for data write and read can be assured even with the track pitch reduced for a higher recording density. Assuming that the refractive index of a medium provided extending from a light-incident surface to a surface in which the grooves and pits are formed is n and the wavelength of a light used for data write and read is &lgr;, the grooves and pits has a width within a range of &lgr;/7.5 n to &lgr;/6. On the assumption that the width of each of the grooves formed in the writable area is Wg and the pitch between the recording tracks in the writable area is Tp1, Wg/Tp1 is within a range of 18.4% to 31.1%. When it is assumed that the width of each of the pitches formed in the read-only area is Wp and the pitch between the recording tracks in the read-only area is Tp2, Wp/Tp2 is within a range of 35.7% to 44.3%.

摘要翻译： 在具有沿着记录磁道形成凹槽的可写入区域和沿着记录磁道形成凹坑的只读区域的光学记录介质中，即使使用轨道也可以确保数据写入和读取所需的足够的信号水平 音高降低，记录密度更高。 假设从光入射表面延伸到形成凹槽和凹坑的表面提供的介质的折射率为n，并且用于数据写入和读取的光的波长为amb条，凹槽和凹坑具有 lambd / 7.5 n至lambd / 6范围内的宽度。 假设在可写入区域中形成的每个槽的宽度为Wg，并且可写入区域中的记录轨迹之间的间距为Tp1，则Wg / Tp1在18.4％至31.1％的范围内。 当假设在只读区域中形成的每个间距的宽度为Wp，并且只读区域中的记录轨道之间的间距为Tp2时，Wp / Tp2在35.7％至44.3％的范围内， 。