The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 10, 2008
Filed:
Dec. 22, 2003
Joachim Knittel, Tuttlingen, DE;
Hartmut Richter, Villingen-Schwenningen, DE;
Joachim Knittel, Tuttlingen, DE;
Hartmut Richter, Villingen-Schwenningen, DE;
Thomson Licensing, Boulogne-Billancourt, FR;
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.