Title:
光記録媒体からの読出し及び/又は光記録媒体への書込みのための装置
Document Type and Number:
Japanese Patent JP4396523
Kind Code:
B2
Abstract:
When an optical recording medium having a plurality of data layers is being read from and/or written to, the input beam experiences an aberration, inter alia in the top layers of the data layers. In order, nevertheless, to achieve a high data density, a device for correcting the spherical aberration is located in the beam path of the input beam. In the case of the use of an optical diode in which the input beam and the reflected beam have directions of polarization perpendicular to one another, such a device is expensive to implement and associated with a reduced optical efficiency. It is an object of the invention to propose an apparatus for reading from and/or writing to optical recording media, in the case of which a high optical efficiency and balancing of the spherical aberration are achieved with low outlay. For this purpose, the device for correcting the spherical aberration is set up such that the reflected beam traverses it uninfluenced, whereby means for correcting the imaging of the reflected beam onto at least one detector unit are provided in the further beam path.
Inventors:
Knittel Yoahim
Richter Hartmut
Richter Hartmut
Application Number:
JP2004566020A
Publication Date:
January 13, 2010
Filing Date:
December 22, 2003
Export Citation:
Assignee:
Thomson Licensing
International Classes:
G11B7/135; G11B7/00
Domestic Patent References:
| JP5151609A | ||||
| JP10134408A | ||||
| JP2003045047A | ||||
| JP2003338075A | ||||
| JP4301226A | ||||
| JP2004310811A | ||||
| JP10269611A | ||||
| JP2002109776A | ||||
| JP8335330A |
Foreign References:
| WO2002073610A1 | ||||
| US5909422 |
Attorney, Agent or Firm:
Keiichi Yamamoto