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: An electric motor comprises a stator (1, 5, 8) having an air-gap which extends around an axis and in which a rotating magnetic field is generated, and a rotor (11, 12, 13) comprising a shaft (11) which is rotatably held by a bearing (10) and a permanent magnet (13) which is held in said air-gap and is driven to rotate around said axis by said rotating magnetic field. The stator (1, 5, 8) is adapted to generate, in addition to said rotating magnetic field, a stationary magnetic field which is rotationally asymmetric with respect to said axis.

Abstract: The invention relates to a method for optimized tracking of an optical scanner along a track of an optical recording medium, the track having information markings arranged in dense succession, and also having fundamental changes in properties in significantly lower density. The method has the following steps: formation of a track error signal, detection of the occurrence of fundamental changes in properties of the track, formation of an offset value from the comparison of the value of the track error signal that occurs shortly before and shortly after the fundamental change in properties, formation of the track error signal, taking account of the offset value and repetition of the aforementioned steps.

Abstract: Reliable scanning of the tracks and a reliable track jump are intended to be ensured even in the case of eccentric optical media and in the case of forces acting externally on an actuator. For this purpose, the tracks crossed by a scanning beam are determined and a count is formed in a track counter. The relative position of the scanning beam with respect to the tracks to be scanned is then regulated on the basis of the count.

Abstract: The address information of DVD-R or DVD-RW discs should be identified more accurately. Therefore, the detector is implemented with a sample/hold device for storing a reference value to be used for a sampling window. An optional integrator is used for comparing the integrated signal with a reference value to decide on the presence of a land pre-pit. The timing for controlling both the sample/hold device and the integrator is derived from a phase locked loop that is locked to the incoming groove wobble signal (TWin) by performing a clock multiplication with a predetermined factor. Advantageously, no band pass filter has to be included, which would need to be tuned according to the variations of the disc speed. Furthermore, the proposed land pre-pit detector is less affected by variations of the input amplitude, as no limiter is used.

Abstract: The present invention relates to a method for recovering land pre-pits from a signal obtained from an optical recording medium.

Abstract: A method for track jumping for optical recording media exhibiting eccentricity, and to an apparatus for reading from and/or writing to optical recording media using such method is disclosed. The method for track jumping for optical recording media exhibiting eccentricity, whereby a sled and/or an actuator are moved from a start track to an end track, includes the steps of: determining the eccentricity of the optical recording medium, initiating the track jump at minimum eccentric acceleration, and completing the track jump at minimum eccentric acceleration.

Abstract: The present invention relates to a method and a circuit for recovering information (INF) contained in a wobble track (36) of an optical storage medium (34). One aim of the invention is to describe a method within an appliance for reading from and/or writing to optical storage media (34), which can correct disturbing data signal components (AS′) in the wobble signal (TW) 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 (A+D, B+C) from two detector halves (1A+1D, 1B+1C) of a photodetector (1) which is used for reading the data contained in a track (36) on an optical storage medium (34) are provided with weighting factors (K1, K2) which are adjusted dynamically during operation of the appliance for reading from and/or writing to optical storage media. In order to adjust the weighting factors (K1, K2), the obtained swept-frequency signal (TW) is linked to a data signal (HF).

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: The present invention relates to an apparatus for reading from and/or writing to optical recording media, which has a tracking device, a four-quadrant detector, two summation points and a phase comparator for tracking in accordance with the differential phase detection method, and also various delay elements that can be set by a control device. The object of the present invention is to propose an apparatus of this type which exhibits the best possible compensation of the error in the track error signal and thus in the tracking signal, the said error being caused on account of the lens movement. To that end, the invention provides for analogue delay elements to be arranged upstream and digital delay elements to be arranged downstream of the summation points. The present invention is suitable for apparatuses for reading from and/or writing to optical recording media, such as CD, CDI, CD-ROM, DVD, CDR and others.

Abstract: In order to generate a lens position signal (LCE), which describes the position of the optical axis of an objective lens (6) of an apparatus for reading from and/or writing to an optical recording medium (7) with regard to the optical axis of the remaining components (2, 3, 4, 5, 8, 9) contained in an optical scanner (21), the application of the DPP method is proposed in accordance with a first exemplary embodiment, wherein a primary-beam error signal (CPP) and a secondary-beam error signal (OPP) are obtained with the aid of the DPP method, wherein the desired lens position signal (LCE) is generated by addition of the primary-beam error signal (CPP) and the secondary-beam error signal (OPP).

Abstract: Track jumping on optical storage media whose address information items invalidate the track error signal (TE) at time intervals is intended to be configured more securely and more reliably. For this purpose, at the end of a coarse jump, one or more correction jumps are carried out if the optical scanner (1) is not presently sweeping over an address information area and the track change frequency of the tracks crossed by the scanner (1) falls below a predetermined value.

Abstract: The track jumping of a scanner (1) 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 (1, 2, 7, 8, 9, 10), which regulates the position of the scanner (1). The regulating circuit (1, 2, 7, 8, 9, 10) is then closed on the basis of the track type defined and a track scanning signal. The reaction of the scanner (1) 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.

Abstract: In an apparatus for reading from and/or writing to an optical recording medium (7), it is desirable, in particular in the case of track jumps, to detect the direction of the track jump, i.e. the direction of movement of an objective lens (6) of the apparatus relative to the optical recording medium (7) in order to be able to carry out corresponding track regulation. For this purpose, and also for determining the number of tracks crossed by the scanning beams (14-18), it is proposed to determine the number of zero crossings and also the phase difference between at least two error signals derived from the reflected scanning beams.

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: 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: 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.

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: 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.