Abstract: An optical scanning device (1) for scanning an information layer (2) of an optical record carrier (3). The device includes a radiation source (7) for providing at least a first radiation beam along a first optical path, and a second radiation beam along a second, different optical path. An objective lens system (8) converges the radiation beams on the information layer A beam-deflecting element (30) is arranged to refract said second radiation beam towards the optical axis of the lens system. The beam-deflecting element includes at least one fluid (A). A controller is provided to vary the configuration of the fluid to control the amount of refraction provided by the beam deflector element over a predetermined range.

Abstract: An optical scanning device for scanning an information layer (2) of an optical record carrier (3). The device includes a radiation source (7) for providing at least a first radiation beam of a first polarization along a first optical path, and a second radiation beam of a second, different polarization along a second, different optical path. An objective lens system, having an optical axis (19a), is arranged to converge the radiation beams on the information layer A beam-deflecting element (30) comprising a birefringent material is orientated such that each of said polarized radiation beams experiences a different index of refraction upon passing through the birefringent material, and is arranged to refract at least the first radiation beam towards the optical axis.

Abstract: In an optical scanning device (10) capable of scanning an information plane of an optical record carrier (5) of different types such as BD, DVD and CD, the diameter of the radiation spot on the detector (7) is dependent on the numerical aperture of the objective system (4) that is used for scanning the record carrier An optimal design of the optical detection system for scanning a BD, result in a small radiation spot for the other types such as DVD and CD.

Abstract: An optical scanning device (1) for scanning at least one information layer (2) of at least one optical record carrier (3). The device includes a radiation source (7) for providing at least a first radiation beam (4) comprising a first wavelength, an objective lens system (8) for converging the first radiation beam on a respective information layer (2), an information detector (23) for detecting at least a portion of the first radiation beam (22) reflected from the respective information layer, for determining information on said layer, and a spherical aberration detection system.

Abstract: An optical scanning device (1) includes a radiation source (7), a detector (23) and a beam splitter (9). The radiation source (7) provides an incident radiation beam (4, 20) along a first optical path (19a) for scanning an information layer (2) of an optical record carrier (3). The detector (23) detects at least a portion of the radiation beam (22) reflected from the optical record carrier (3). The beam splitter (9) transmits the incident radiation beam (4) received from the radiation source along the first optical path (19a) towards the optical record carrier. The beam splitter (9) also transmits the reflected beam (22) received from the optical record carrier (3) along a second, different optical path (19b) towards the detector. The optical scanning device further includes a beam-deflecting element (30; 130; 230; 330; 630; 830; 930) positioned on the second optical path (19b) between the beam splitter (9) and the detector (23).

Abstract: The present invention relates to a symbol detection apparatus for detecting the symbol values of a one-dimensional channel data stream recorded along one-dimensional contiguous tracks on a record carrier, wherein the symbols of adjacent tracks have a varying phase relation.

Abstract: A driver for driving a light generator for generating light, comprising a digitalto-analog converter (DAC) having a data input, a data output for generating an analog signal, a first multiplexer (MUX1) for cyclic selection of a number of data levels corresponding to desired intensity levels of the light and for coupling the data levels to the data input; a de multiplexer (DE-MUX) synchronized with the first multiplexer (MUX1) for de-multiplexing the analog signal into a set of analog signals; memory means for temporarily storing the set of analog signals; and a second multiplexer (MUX2) for selection of the stored set of analog signals and for generating a drive signal (IL) for the light generator. The memory means is preferably implemented by a set of capacitors (C1-C8). Usually, for instance in an optical disc drive, the light generator is implemented by a laser (Ls).

Abstract: The present invention relates to an encoding apparatus and a corresponding method for two-dimensionally encoding user data of a user data stream into channel data of a channel data stream along a two-dimensional channel strip of at least two bit rows one-dimensionally evolving along a first direction and being aligned with each other along a second direction, said two directions constituting a two-dimensional lattice of bit positions. According to the invention the apparatus comprises a modulation code encoder for modulation code encoding said user data into said channel data according to a two-dimensional modulation code being adapted to prevent predetermined worst case patterns of channel data in said channel data stream. The worst-case patterns are typical for high-density two-dimensional optical storage channels.

Abstract: Disclosed is a bit-detection arrangement able to convert an analog signal (AS) having an amplitude into a digital signal (DS) representing a bit sequence from which the analog signal (AS) is derived. The bit-detection arrangement has a phase detector which detect the phase difference between a quantized analog signal and a clock signal C2. The phase difference is sampled by an AD converter. The AD converter can sample at a relatively slow rate as the phase difference is a low frequency signal. The sampled phase difference is fed to a digital PLL which outputs a phase signal PHI. The phase signal and the quantized analog signal are used to recreate the digital signal (DS).

Abstract: A Viterbi bit detection method for detecting the bit values of bits of a channel data stream stored on a record carrier along an N-dimensional channel tube, N being at least two, of at least two bit rows one-dimensionally evolving along a first direction and being aligned with each other along at least a second of N?1 other directions, the first direction together with the N?1 other directions constituting an N-dimensional lattice of bit positions, includes application of a row-based one-dimensional Viterbi bit detection method independent for each of the bit rows of said channel tube.

Abstract: A record head for the thermally assisted magnetic recording on a storage medium. The head has an inductive section, which includes a magnetic circuit having a record flux guide ending in a record pole, and an optical section, which includes an optical guide ending in an optical outlet. The optical guide is arranged beside the magnetic circuit and is an optical layer transparent to a selected wavelength. The optical layer is interposed between two cladding layers, of which one is formed by the record flux guide of the magnetic circuit and the other is formed by a layer having an index of refraction smaller than the index of refraction of the optical layer. The record head makes it possible to minimize the time that elapse between the moment of maximal energy absorption in the medium and the moment of recording on the medium in a thermally assisted recording process.

Abstract: A servo system comprising an analog sigma delta modulator for generating a normalized digital error correction signal from first and second analog control signals. The sigma delta modulator comprises an analog low-pass filter, a quantizer delivering the digital error correction signal and a multiplying DA-converter in feedback arrangement between the output of the quantizer and the input of the low-pass filter for multiplying the feedback signals with the sum of the analog control signals.