公开(公告)号：US06785215B2

公开(公告)日：2004-08-31

申请号：US09967998

申请日：2001-10-02

申请人： Takashi Yamanouchi ,  Koichi Maruyama

发明人： Takashi Yamanouchi ,  Koichi Maruyama

IPC分类号： G11B7135

CPC分类号： G11B7/1353 ,  G11B7/1374 ,  G11B7/13922 ,  G11B2007/0006 ,  G11B2007/13727

摘要： An objective lens for an optical head converges a first laser beam having a relatively short wavelength and a second laser beam having a relatively long wavelength on first optical disc (DVD) and a second optical disc (CD), respectively. A protective layer of the first disc is thinner than a protective layer of the second optical disc. The objective lens is compensated for astigmatism with respect to the first beam, which is incident on the objective lens as an off-axis beam at a predetermined incident angle, by providing on-axis astigmatism corresponding to wave front aberration greater than or equal to 0.01&lgr; (rms), and the objective lens is configured such that the coma is compensated better in a case where the first laser beam is converged on the first optical disc than in a case where the second laser beam is converged on the second optical disc.

摘要翻译： 用于光学头的物镜分别在第一光盘（DVD）和第二光盘（CD）上会聚具有较短波长的第一激光束和具有较长波长的第二激光束。 第一盘的保护层比第二光盘的保护层薄。 通过提供对应于大于或等于0.01的波前像差的轴上散光，物镜相对于作为离轴光束以预定入射角入射在物镜上的第一光束补偿像散 λ（rms），并且物镜被配置为使得在第一激光束会聚在第一光盘上的情况下比在第二激光束会聚在第二光盘上的情况下更好地补偿彗差。

公开(公告)号：US06473387B1

公开(公告)日：2002-10-29

申请号：US09655880

申请日：2000-09-06

申请人： Koichi Maruyama ,  Takashi Yamanouchi

发明人： Koichi Maruyama ,  Takashi Yamanouchi

IPC分类号： G11B700

CPC分类号： G11B7/1353 ,  G11B7/123 ,  G11B7/1275 ,  G11B7/1374 ,  G11B7/13922 ,  G11B2007/0006

摘要： Disclosed is an optical disc apparatus that is adapted for DVD, CD and CD-R. The optical system includes a laser module and an objective lens that converges a divergent laser beam emitted from the laser module onto information layers of optical discs. The laser module is provided with a pair of emission points that are in close proximity to each other, and a pair of light receiving elements. A focusing mechanism moves the objective lens so that the beam spot follows an information layer of the optical disc. The objective lens is provided with the diffractive lens structure to have a wavelength dependence such that the spherical aberration varies in response to the change of the wavelength. Thereby, the variation of the spherical aberration due to the change of the thickness of the cover layer can be canceled by changing the wavelength.

摘要翻译： 公开了适用于DVD，CD和CD-R的光盘装置。 光学系统包括激光模块和物镜，其将从激光模块发射的发散激光束会聚到光盘的信息层上。 激光模块设置有彼此非常接近的一对发射点和一对光接收元件。 聚焦机构使物镜移动，使得光点跟随光盘的信息层。 物镜设置有衍射透镜结构以具有波长依赖性，使得球面像差响应于波长的变化而变化。 由此，可以通过改变波长来抵消由于覆盖层的厚度变化引起的球面像差的变化。

公开(公告)号：US06807018B2

公开(公告)日：2004-10-19

申请号：US10402932

申请日：2003-04-01

申请人： Koichi Maruyama ,  Takashi Yamanouchi

发明人： Koichi Maruyama ,  Takashi Yamanouchi

IPC分类号： G02B302

CPC分类号： G02B27/0037 ,  G11B7/1275 ,  G11B7/1374 ,  G11B7/13922 ,  G11B2007/0006

摘要： An objective lens of an optical pick-up is formed to provide axial astigmatism corresponding to wavefront aberration of 0.01&lgr; [rms] or more when a shorter wavelength laser beam emitted by a first laser diode is converged on a first optical disc, and to provide coma so that its sign when the shorter wavelength laser beam is converged on the first optical disc will be opposite to its sign when a longer wavelength laser beam emitted by a second laser diode is converged on a second optical disc.

摘要翻译： 当由第一激光二极管发射的较短波长的激光束会聚在第一光盘上时，形成光学拾波器的物镜，以提供对应于0.01λ[rms]或更大的波前像差的轴向像散，并提供 使得当较短波长的激光束会聚在第一光盘上时的符号将与其第二激光二极管发射的较长波长的激光束会聚在第二光盘上时的符号相反。