Patents by Inventor Heinz-Jorg Schroeder

Heinz-Jorg Schroeder has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7336566
    Abstract: The track jumping of a scanner on optical storage media in which information items are stored on groove and land tracks or which have not yet been written to is intended to be made possible in a reliable manner. For this purpose, firstly a fictitious track type is defined for a regulating circuit, which regulates the position of the scanner. The regulating circuit is then closed on the basis of the track type defined and a track scanning signal. The reaction of the scanner to the closing is detected in order to obtain from this an item of information about the track type. This method is also advantageous, in principle, for closing the track following regulation in information carriers having relatively high storage densities.
    Type: Grant
    Filed: December 10, 2001
    Date of Patent: February 26, 2008
    Assignee: Thomson Licensing
    Inventors: Heinz-Jörg Schröder, Christian Büchler, Stefan Kimmelmann
  • Patent number: 7280459
    Abstract: A device for reading from and/or writing to optical recording media 10, on which information is present in the form of pits, with a linearly polarized light beam 2. A device for reading from and/or writing to optical recording media 10 which ensures correct reproduction of the stored data even when the recording medium influences the polarization of the light beam 2.
    Type: Grant
    Filed: March 31, 2003
    Date of Patent: October 9, 2007
    Assignee: Thomson Licensing
    Inventors: Lieu-Kim Dang, Heinz-Jörg Schröder
  • Patent number: 6678222
    Abstract: The present invention relates to an apparatus for reading from and/or writing to optical recording media with optical scanner, light source, focusing means, tilting-detection device and tilting-compensation device. The object of the invention is to propose an apparatus and a method, which enables optimum compensation of tilting using as few apparatus functions as possible. This is achieved according to the invention by using a tilting-detection device comprising an optical grating, a detector element, a control device for controlling light source and the focusing means and a control device controlling for the tilting-compensation device.
    Type: Grant
    Filed: April 26, 2000
    Date of Patent: January 13, 2004
    Assignee: Thomson Licensing, S.A.
    Inventors: Heinz-Jörg Schröder, Lieu Kim Dang
  • Patent number: 6574183
    Abstract: The present invention relates to a device for reading from or writing to optical recording media, which device has a scanning beam generation means, a focusing means and a photodetector comprising at least two detector zones and serving to receive zeroth- and first-order diffraction beams from the recording medium. The object of the invention is to obtain a reduction in interfering influences in a signal derived from signals of the photodetector, a signal such as, for example, a focus error signal or a track error signal. This object is achieved by virtue of the fact that a beam splitting means is provided, which splits a light spot falling onto the photodetector into two separate partial spots. The device is, for example, a CD or DVD player, but in particular a recording and reproduction device for so-called DVD-RAMs or similar optical recording media.
    Type: Grant
    Filed: March 28, 2002
    Date of Patent: June 3, 2003
    Assignee: Thomson Licensing, S.A.
    Inventors: Lieu Kim Dang, Christoph Dietrich, Hartmut Richter, Heinz-Jörg Schroeder
  • Patent number: 6430141
    Abstract: A device for reading from or writing to optical recording media comprising a scanning beam generation means, a focusing means and a photodetector comprising at least two detector zones and serving to receive zeroth- and first-order diffraction beams from the recording medium. The object of the invention is to obtain a reduction in interfering influences in a signal derived from signals of the photodetector, a signal such as, for example, a focus error signal or a track error signal. This object is achieved by virtue of the fact that a beam splitting means is provided, which splits a light spot falling onto the photodetector into two separate partial spots. The device is, for example, a CD or DVD player, but in particular a recording and reproduction device for so-called DVD-RAMs or similar optical recording media.
    Type: Grant
    Filed: April 8, 1999
    Date of Patent: August 6, 2002
    Assignee: Thomson Licensing, S.A.
    Inventors: Lieu Kim Dang, Christoph Dietrich, Hartmut Richter, Heinz-Jörg Schroeder
  • Publication number: 20020101813
    Abstract: The present invention relates to a device for reading from or writing to optical recording media, which device has a scanning beam generation means, a focusing means and a photodetector comprising at least two detector zones and serving to receive zeroth- and first-order diffraction beams from the recording medium.
    Type: Application
    Filed: March 28, 2002
    Publication date: August 1, 2002
    Inventors: Lieu Kim Dang, Christoph Dietrich, Hartmut Richter, Heinz-Jorg Schroeder
  • Patent number: 6285641
    Abstract: A device for writing to and/or reading from optical recording media having different structures is described, for example, a device which is suitable both for writing to/reading from digital videodisks (DVD) and conventional CD's. Provision is made for measuring the intensity of each peak in the mirror signal while the objective lens is moving to the recording medium. The intensity e.g. at the instant of the positive-negative crossing of the focus error signal is taken in this case. The type of optical recording medium is determined from the time characteristic and/or the height distribution of the peaks. In order to identify the type of optical recording medium, different properties of the optical recording medium are taken into account, such as reflectivity of the corresponding reflective surface, reduced intensity modulation due to spherical aberration, time characteristic and the like.
    Type: Grant
    Filed: September 3, 1998
    Date of Patent: September 4, 2001
    Assignee: Deutsche Thomson-Brandt GmbH
    Inventors: Lieu Kim Dang, Friedhelm Zucker, Heinz-Jörg Schroeder
  • Patent number: 6195318
    Abstract: Method for the correction of a tracking error signal during optical scanning of a recording medium in the form of a disc. In the case of MO discs, the Kerr rotation angle is in general very small, so that so-called enhancement is used for processing. This leads to birefringence effects which are thermally induced on the WO disc during the writing process producing a noise level on the track error signal. According to the invention, an optical scanner arrangement is used to determine light intensities from two mutually perpendicular polarization planes. A noise element, which is produced by interfering polarization rotation of the light, in the tracking error signal is compensated by linking the electrical output signals of the scanner arrangement. Applicable both to MO and WO as well as CD audio, CD video and CD-ROM.
    Type: Grant
    Filed: December 8, 1998
    Date of Patent: February 27, 2001
    Assignee: Deutsche Thomson-Brandt GmbH
    Inventors: Stefan Rapp, Heinz-Jörg Schroeder, Friedhelm Zucker