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公开(公告)号：EP0459764A2
公开(公告)日：1991-12-04
申请号：EP91304820.3
申请日：1991-05-29
发明人： Miyake, Takahiro , Yoshida, Yoshio , Kurata, Yukio
CPC分类号： G11B7/1353 , G11B7/094 , G11B7/131 , G11B7/1359 , G11B7/1398
摘要： An optical head device having an optical system provided with at least a light source (10), a shaping prism, an diffracting element (20) and a photodetector (60). The light source emits light whose intensity distribution has an elliptic shape in its cross section orthogonal to the optical axis. The shaping prism directs the light to a recording medium (70) after shaping the intensity distribution thereof into a circular shape. The diffracting element has diffracting regions formed by at least one division line substantially parallel to a reference direction. The light reflected from the recording medium forms an elliptic bright portion on the diffracting element. The photodetector is divided by a plurality of division lines (64, 65), at least one of which is parallel to the reference direction. When there is no focus error, the diffracting element diffracts the reflected light so as to converge it on the division line substantially parallel to the reference direction in the photodetector. For example, when the shaping prism is adapted to shape the elliptic intensity distribution with respect to its minor axis direction, the optical system is arranged so that the major axis of the bright portion is parallel to the division line of the diffracting element. Thus, it is possible to suppress offsets in focusing control due to wave-length variations of light.
摘要翻译： 一种具有至少设置有光源（10），成形棱镜，衍射元件（20）和光电检测器（60）的光学系统的光学头装置。 光源在其与光轴正交的横截面中发射其强度分布具有椭圆形的光。 成形棱镜在将其强度分布形成圆形之后将光引导到记录介质（70）。 衍射元件具有基本上平行于基准方向的至少一个划分线形成的衍射区域。 从记录介质反射的光在衍射元件上形成椭圆形亮部。 光电检测器由多个划分线（64,65）分隔开，其中至少一条与基准方向平行。 当不存在聚焦误差时，衍射元件将反射光衍射，使其在基本上平行于光检测器中的基准方向的分割线上会聚。 例如，当成形棱镜适于使其相对于其短轴方向成形椭圆强度分布时，光学系统被布置成使得亮部的长轴平行于衍射元件的分割线。 因此，可以抑制由于光的波长变化引起的聚焦控制中的偏移。
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公开(公告)号：EP0453323A2
公开(公告)日：1991-10-23
申请号：EP91303579.6
申请日：1991-04-22
发明人： Miyake, Takahiro , Yoshida, Yoshio , Kurata, Yukio
CPC分类号： G02B27/0972 , G02B13/10 , G02B19/0028 , G02B19/0052 , G02B19/0085 , G02B27/09 , G11B7/0916 , G11B7/094 , G11B7/1353 , G11B7/1359 , G11B7/1398
摘要： An optical pickup device having an optical system provided with at least a light source (11), a shaping prism (14), an diffracting element (12) and a photodetector (17). The light source projects light whose intensity distribution has an elliptical shape in its cross section orthogonal to the optical axis. The shaping prism directs the light to a recording medium after shaping the intensity distribution thereof into a circular shape. The diffracting element (12) has diffraction regions formed by at least one division line substantially parallel to a reference direction. The light reflected from the recording medium forms an elliptical bright portion on the diffracting element. The photodetector (17) is divided by a plurality of division lines, at least one of which is substantially parallel to the reference direction. The diffracting element diffracts the reflected light so as to converge it on the photodetector. Here, a hypothetical line extending from a projecting point of the light source through the center of a light-receiving face of the photodetector is also set to be parallel to the reference direction. For example, when the shaping prism is to shape the intensity distribution having the elliptical shape with respect to its minor axis direction, the optical system is arranged so that the minor axis of the bright portion is parallel to the division line of the diffracting element. Thus, it is possible to always obtain an accurate focusing control signal.
摘要翻译： 一种光拾取装置，其具有至少设置有光源的光学系统，成形棱镜，衍射元件和光电检测器。 光源投射其光轴在垂直于光轴的截面中具有椭圆形形状的光。 成形棱镜将其强度分布成形为圆形后将光引导到记录介质。 衍射元件具有基本上平行于基准方向的至少一个分割线形成的衍射区域。 从记录介质反射的光在衍射元件上形成椭圆形亮部。 光电检测器由多条分割线分开，其中至少一条与基准方向基本平行。 衍射元件衍射反射光，使其聚光在光电检测器上。 这里，从光源的突出点延伸通过光电检测器的光接收面的中心的假想线也被设置为平行于参考方向。 例如，当成形棱镜相对于其短轴方向成形具有椭圆形的强度分布时，光学系统被布置成使得亮部的短轴平行于衍射元件的分割线。 因此，可以总是获得精确的聚焦控制信号。
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公开(公告)号：EP0380320A2
公开(公告)日：1990-08-01
申请号：EP90300741.7
申请日：1990-01-24
CPC分类号： G11B7/1353 , G11B7/123
摘要： An optical pickup apparatus for reading out information from an optical disk. The optical pickup apparatus comprises a light source (1) and an optical device (2) having a grating pattern for splitting a light beam from said source into a zero-order diffracted beam and plus and minus first-order diffracted beams. The grating pattern has a centre portion (a) and one or more side portions (b). The efficiency of the centre portion (a) for the zero-order diffracted beam is greater than the efficiency of the side portions (b) for the zero-order diffracted beam.
摘要翻译： 一种用于从光盘读出信息的光学拾取装置。 光拾取装置包括光源（1）和具有光栅图案的光学装置（2），用于将来自所述源的光束分成零级衍射光束以及正负衍射光束。 光栅图案具有中心部分（a）和一个或多个侧面部分（b）。 零级衍射光束的中心部分（a）的效率大于零级衍射光束的侧部（b）的效率。
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44.发明公开An external magnetic field device for a magnetooptical information recording and reproducing apparatus 失效ÄussereMagnetfeldvorrichtungfürein magneto-optisches Aufzeichnungs- undWiedergabegerät。
公开(公告)号：EP0352099A2
公开(公告)日：1990-01-24
申请号：EP89307336.1
申请日：1989-07-19
发明人： Miyake, Tomoyuki , Katayama, Hiroyuki , Nakayama, Junichiro , Miyake, Takahiro , Ohta, Kenji , Kobayashi, Shozo
IPC分类号： G11B11/10
CPC分类号： G11B11/10508
摘要： An external magnetic field device for a magnetooptical information recording and reproducing apparatus in which an external magnetic field to be applied to a magnetooptical information recording medium is modulated by supplying to a magnetic head (3) an alternate current the polarity of which is changed according to information to be recorded. The device comprises an offset circuit (2) for producing an offset in the alternate current. The direction of the offset is selected so as to increase the current level of the polarity by which the initial magnetization of the information recording medium (4) is reversed. The direction of the offset may be selected so as to cancel the leakage magnetic field.
摘要翻译： 一种用于磁光信息记录和再现装置的外部磁场装置，其中通过向磁头（3）提供施加到磁光信息记录介质的外部磁场，磁极（3）的极性根据 要记录的信息 该装置包括用于在交流电中产生偏移的偏置电路（2）。 选择偏移的方向以增加信息记录介质（4）的初始磁化反转的极性的电流电平。 可以选择偏移的方向以抵消泄漏磁场。
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