Thomson Licensing

Deutsche Thomson-Brandt Gmbh

Thomson Licensing S.a.

Christian Büchler

Christoph Dietrich

Marten Kabutz

Stefan Kimmelmann

Friedhelm Zucker

Hartmut Richter

Stephan Knappmann

Steffen Lehr

Holger Hofmann

Gerhard Reiner

Christof Ballweg

Martin Kuner

Heinz-Jörg Schröder

Uwe Reschke

Pierluigi Lo Muzio

Eric Fani

Jürgen Mössner

Yasuaki Morimoto

The invention relates to a method for storing data in a prerecorded area of an optical recording medium, and to an optical recording medium having at least one prerecorded area in which data is stored according to the method. It is an object to propose a method for storing data in a prerecorded area of an optical recording medium using pits and lands, whereby the signal obtained from the pits and lands is compatible with a high frequency modulated groove signal. According to the invention, the pits and lands adjacent to bit cell signal transitions are arranged in a predefined manner, either in a fixed recurring sequence of pits and lands or symmetrically to the bit cell signal transitions.

Method for storing data on an optical recording medium

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.

Track jumping for optical recording media

A lens position signal LCE which indicates the discrepancy between the lens and its geometric mid-position is required for coarse tracking of optical storage drives. The prior art is for the lens position signal LCE to be formed in three-beam pick-ups by weighted combination of specific photodetector signals from a primary beam and secondary beam. The only way to ensure that the lens position signal is free of crosstalk caused by the tracking error signal is for the weights to be set correctly. The invention describes methods by means of which the weights can be adjusted automatically and can be matched to the characteristics of the pick-up and of the respective storage medium. The amplitudes of those components in the main and secondary beam signals which are dependent on the tracking error are measured, and the matched weights are determined from them by joint evaluation. Evaluations with synchronous detection and with time integration are described, some of which can be used during writing and reading.

Method for gain adjustment for production of a lens position signal, and a corresponding appliance for reading from and/or writing to an optical recording medium

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.

Optimized tracking method

In order to obtain a corrected or compensated focus error signal or track error signal, it is proposed to generate primary and secondary scanning beams incident on adjacent tracks of an optical recording medium and to detect the primary and secondary scanning beams reflected from the optical recording medium in order to derive from them primary-beam and secondary-beam focus error signals or primary-beam and secondary-beam track error signals, which are subsequently normalized in order to obtain the compensated focus error signal or track error signal from the normalized primary-beam and secondary-beam error signals by means of weighted combinations. As a result of the normalization, the corrected or compensated focus error signal or track error signal is generated independently of the reflection properties of the respectively scanned track.

Method for generating a corrected error signal, and corresponding apparatus

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

Electric motor

In an apparatus for reading from and/or writing to an optical recording medium, 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 of the apparatus relative to the optical recording medium 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, 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.

Method for track counting and corresponding apparatus for reading from and/or writing to an optical recording medium

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.

Method and apparatus for track type identification, and method of track jump

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.

Method and device for detecting land pre-pits

In order to generate a lens position signal, which describes the position of the optical axis of an objective lens of an apparatus for reading from and/or writing to an optical recording medium with regard to the optical axis of the remaining components contained in an optical scanner, the application of the DPP method is proposed in accordance with a first exemplary embodiment, wherein a primary-beam error signal and a secondary-beam error signal are obtained with the aid of the DPP method, wherein the desired lens position signal is generated by addition of the primary-beam error signal and the secondary-beam error signal. In accordance with a second exemplary embodiment, it is not necessary to generate a primary beam, rather it suffices to detect the secondary beams reflected from the optical recording medium in order to obtain the lens position signal by addition of the secondary-beam error signals generated in a manner dependent thereon.

Method for generating a lens position signal and corresponding apparatus for reading from and/or writing to an optical recording medium

The present invention relates to a method for recovering land pre-pits from a signal obtained from an optical recording medium. According to the invention, the method comprises the steps of:

Method for land pre-pit recovery

Track jumping on optical storage media whose address information items invalidate the track error signal 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 is not presently sweeping over an address information area and the track change frequency of the tracks crossed by the scanner falls below a predetermined value.

Method for position control in optical data carriers with address information

An apparatus for reading from or writing to optical recording media, having a photodetector and a phase detector for detecting a phase difference between output signals of the photodetector. An object of the present invention is to propose an apparatus in which a phase signal which is as correct as possible is generated. A further object of the invention is to specify a method of which a correct track error signal is determined using a phase detection method. According to the invention, the apparatus has an edge sequence detector for detecting the sequence of edges of the output signals, and a signal blocking unit for blocking the output signal of the phase detector. In particular, the output signal of the phase detector is blocked when an impermissible sequence of zero crossings of phase detected signals.

Apparatus for scanning optical recording media using a differential phase detection method

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.

Apparatus for scanning optical recording media using DPD tracking method with analog and digital delay elements

The present invention relates to a method and a circuit for recovering information contained in a wobble track of 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 for reading from and/or writing to optical storage media. In order to adjust the weighting factors, the obtained swept-frequency signal is linked to a data signal.

Growing community of inventors

Villingen-Schwenningen, Germany

Christian Büchler