Abstract: An apparatus for reading and/or writing data markings of an optical recording medium having data markings arranged along a track and header markings arranged laterally offset with respect to the center of the track, the apparatus having a header identification unit. According to the present invention an intermediate track signal is formed, which enables direction identification during the traversal of tracks. The present invention comprises an apparatus having a header sequence detector, a track crossing detector and an intermediate track detector, wherein the intermediate track detector is connected to outputs of the header identification unit, the track crossing detector and the header sequence detector, and generates an intermediate track signal.

Abstract: Method for tracking in an apparatus for reading from and/or writing to an optical recording medium, and corresponding apparatus for reading from and/or writing to an optical recording medium. In order, in an apparatus for reading from and/or writing to an optical recording medium (18), to enable exact counting of the tracks of the optical recording medium (18) crossed by an optical scanning unit (16), it is proposed to derive a signal corresponding to the TZC signal (Tracking ZeroCross) and also a signal corresponding to the MZC signal (Mirror Zero Cross) from the output signal or the output signals (OUT1, OUT2) of a phase comparator (1) provided for tracking in accordance with the so-called differential phase detection method.

Abstract: The present invention relates to a method and a circuit for recovering information contained in a wobbled track on an optical storage medium. One aim of the invention is to describe a method within an appliance for reading from and/or writing to optical storage media, which can correct disturbing data signal components in the wobble signal even when the swept frequency and the lowest signal frequency are close to one another. According to the invention, this object is achieved in that the signals from two detector halves of a photodetector which is used for reading the data contained in a track on an optical storage medium are provided with weighting factors which are adjusted dynamically during operation of the appliance. In order to adjust the weighting factors, the data signal component in the wobble signal is linked to a disturbance signal from a disturbance signal generator.

Abstract: The present invention relates to a device for reading from and/or writing to optical recording media having a scanning unit, which is equipped with at least two detector units each having a plurality of detector elements, and also an evaluation unit, each of the detector elements being connected to the evaluation unit by means of a line. The object of the present invention is to simplify the structure of a device of this type. This object is achieved by virtue of the fact that detector elements of different detector units are each connected to the evaluation unit via a single line. The device according to the invention is advantageously a device which can read from and/or write to not only optical recording media which correspond to a CD standard but also those which correspond to a DVD standard.

Abstract: A device for reading from and/or writing to optical recording media, the device comprising a light source for producing a scanning beam, a photodetector for detecting the scanning beam reflected by the recording medium and a semi-transparent mirror arranged in the beam path for directing the scanning beam onto the recording medium and the reflected scanning beam onto the photodetector. An object of the invention is to improve a device of this type, in particular with regard to reducing the production costs. This object is achieved by the semi-transparent mirror being a plane-parallel plate with a layered structure, and a partially reflective layer being arranged between two small carrier plates.

Abstract: The present invention relates to a device for reading from and/or writing to an optical recording medium, which has a data track having a first area, which is provided for markings arranged centerd with respect to the center of the data track, and at least one further area, which is provided for markings arranged laterally offset with regard to the center of the data track. Corresponding devices have detection means, track error detector, signal shaping means, and correction signal generation means. The object of the present invention is to propose a device of the generic type in which an accurate correction signal for the track error signal can be obtained without a high outlay, and also a method for generating a corresponding correction signal. This object is achieved according to the invention by the fact that the signal shaping means has an averaging unit, whose output is connected to an input of the correction signal generation means.

Abstract: A photodiode detection circuit is used to automatically identify a type of photodiode circuit connected to it. The photodiode circuit comprises at least a photodiode. Once the type of photodiode circuit has been identified by applying a current to it and evaluating a voltage occuring at an input of the detection circuit the photodetection circuit adapts itself to it, e.g. a reverse biasing voltage is/isn't applied to the photodiode of the photodiode circuit. The result is a photodiode detection circuit which uses a forward or a reversed biased photodiode. The photodiode detection circuit is now in a state to measure light falling on the photodiode. The detection circuit may be part of a light intensity monitoring and controlling circuit which allows to regulate the intensity of a laser beam in an optical disk reading/recording device.

Abstract: In order to more quickly produce read and/or write readiness of an apparatus for reading from and/or writing to an optical recording medium, in particular a DVD-ROM disc, it is proposed to read or to detect identification features, such as, for example, the “BCA data area” which individually identifies the respective recording medium and, after identification of the respectively inserted optical recording medium, to check whether adjustment parameters for the write and/or read unit of the apparatus have already been stored beforehand for this optical recording medium in a storage device. If this is the case, the adjustment parameters can be read from the storage device and be used as start values for the adjustment of the write and/or read unit.

Abstract: The invention concerns an apparatus for reading or writing optical recording carriers, the apparatus using the differential phase detection process for tracking purposes. This process exhibits shortcomings when optical recording carriers of different pit depths are to be used. The object of the invention is to design an apparatus of this type which can also be used with said optical recording carriers. This object is achieved in that delay members are disposed between the photodetector and phase detector. The apparatus according to the invention is used as a playback or recording apparatus for optical recording carriers, such as CDs, CD-ROMs, CD-Is, CD-Rs, DVDs, DVD-ROMs, DVD-Rs, etc.

Abstract: The present invention relates to a device for reading from and/or writing to optical recording media, which has a tracking unit, a four-quadrant detector, two summation points and a phase comparator for tracking in accordance with the differential phase detection method, and also two variable delay elements which can be set by a control unit. The device has improved compensation of the error in the track error signal and thus in the tracking signal. The error is caused by lens movement. An interference signal generating unit whose output is connected to the tracking unit and to a first input of the control unit, the second input of which is connected to the output of the phase comparator for providing error compensation.

Abstract: A recording or reproduction device with a three-point scanning arrangement compatible for use with recording media having different track spacings. The invention makes it possible, without changing the setting of the three-point scanning system, to use recording media having different track spacings. According to the invention, the three-point scanning system is set in such a way that the scanning center points have a lateral spacing from one another which is within a range of a first product, formed by a first predetermined value and the first track spacing, and a second product, formed by a second predetermined value and the second track spacing, the range being less than 8 percent of the value of the first product.

Abstract: A device for corrected-focus scanning of information while recording on and/or replaying information from a recording medium is based on a radiation source which provides a scanning beam, a focusing objective lens and a radiation-sensitive detector system. A diffraction element for deriving a focus error signal is arranged in the space between the focusing objective lens and the detector system, at a predetermined, fixed distance, the diffraction element being designed such that two focus planes result which are physically separated from one another. The detector system is located between the separate focus planes such that the size ratios, which change in the event of defocusing, of the symmetrically imaged focus spot can be used to derive the focus error signal.