Abstract: During the recording of packetized data streams with a low bit rate, the packets are stored in data blocks having a constant size. Time stamps are used for the addressing of the data blocks, which time stamps describe the time duration which, in the case of the bit rate respectively present, is necessary for complete filling of a data block. A maximum time duration is prescribed, which corresponds to complete filling of a data block in the case of a predetermined minimum value of the bit rate. In the case of the minimum value of the bit rate being undershot, the last packet, in the time window of the maximum time duration of a data block, is not stored in this data block but rather in the subsequent data block.

Abstract: An objective lens of an optical pickup apparatus converges a divergent light flux onto an information recording surface. The following conditional formula is satisfied: |?SA1/?U|·|?U|+|?SA2/?T|·|?T|?0.07 ?rms where ? represents a wavelength of a light source, ?SA1/?U represents a change of a spherical aberration for an object-to-image distance change ?U (|?U|?0.5 mm) and ?SA2/?T represents a change of spherical aberration for a temperature change ?T (|?T|?30° C.), the object-to-image distance is a distance between the light source (a light emitting point) and the information recording surface.

Abstract: The present invention relates to an optical media system (40) for suppressing externally induced rattle of an optical media pickup. The system (40) comprises: an optical pickup (41) for reading from and/or writing to an optical storage medium (43), the optical pickup (41) having one or more sources of light (61), an objective lens (2), a focus and/or tracking actuator (1) for moving the lens (2) to focus and/or track the light on the optical medium (43) and mechanical limits to limit the focus and/or tracking movement of the lens (2); and an actuator controller (58) for controlling the actuator (1) and hence the focus and/or tracking position of the lens (2), characterised in that the actuator controller (58) actively controls the lens position when the optical pickup (41) is not being used with the optical medium (43).

Abstract: The invention relates to an optical disc device and a control method for the optical disc device. The presence of defects on an optical disc is confirmed by, based on the result of detecting a return light corresponding to a sub-beam spot used for tracking control, which is formed on the preceding side with respect to scan of a main beam spot, suppressing changes in signal level of the light detection result caused upon boosting of the laser power of a laser beam. Also, whether data can be correctly reproduced is determined by, based on the result of detecting a return light corresponding to a sub-beam spot used for tracking control, which is formed on the succeeding side with respect to scan of the main beam spot, suppressing changes in signal level caused upon writing of the data. Therefore, whether data can be correctly reproduced can be confirmed with a simple construction while effectively avoiding a reduction of the data transfer rate.

Abstract: An apparatus includes a controller storing information on dense/sparse state of the tracking error signal in connection with characteristic of the signal generated by a phase encoder while tracking servo of a servo unit is inactivated, and, in data reproduction mode, identifying a current disk phase based on characteristic of the signal generated by the phase encoder, and adjusting tracking characteristic of the servo unit based on the stored information in connection with the signal characteristic in order to compensate an effect rate of eccentricity on the identified disk phase. Through minute adjustment of servo characteristic for each disk phase, error range of TE signal to track in real time is reduced. Therefore, tracking for an eccentric disk becomes easier and more reliable.

Abstract: A optical device including conductive films having a first and second surfaces, one hole, surface specific shapes periodically, and a layer inserted as an intermediate layer between the first and the second surface of conductive films. The intermediate layer has the effect for improving surface roughness of the surface of conductive film. A light incident upon one surface enhances an intensity transmitted though the hole.

Abstract: A device for reading and/or writing a record carrier (13), the device comprising converging means (35, 45, 47, 106, 108) for focusing a radiation beam (27, 101) originating from a radiation source (25) on the record carrier (13). The converging means comprises polarization means (103) and a diffraction grating (107) of birefringent material. Dependent on the direction of polarization, the radiation beam (101) is focused on one of two possible surfaces corresponding to DVD and DVR, respectively. A diffraction grating (107) is present in a central area of the radiation beam (101) and causes diffraction of a first order for one direction of polarization of the radiation beam (101) and diffraction of a second, higher, order for a second direction of polarization of the radiation beam (101). The diffraction grating (107) is made of birefringent material.

Abstract: An optical head of a type useable in a optical disk reader/writer is provided. One of the optical elements is provided in a fashion that one or more optical parameters or characteristics of the system are invariant, regardless of whether the one optical element is used, or not. In one embodiment the optical element is a beamshaper. In order to provide the desired invariant property, the surfaces of the optical element are preferably formed with high accuracy. One manner of economically achieving high accuracy is to measure errors or imperfections in a first formed, preferably etched, surface and adjust the shape or position of a second aligned etched surface so as to at least partially compensate for the errors or imperfections.

Abstract: An eccentricity compensating apparatus of a disk drive servo system using frequency response characteristics of an actuator actuating a head to a position on a disk to read data on or reproduce data from the disk. The apparatus includes an error detector that detects a position error between a reference head position and an actual position of the head on the disk and a first compensation controller that receives the position error from the error detector and changes the actual position of the head to compensate for the position error.

Abstract: An objective lens supporting apparatus of an optical pickup includes a lens frame in which an objective lens is mounted; receiving member for receiving driving forces for displacing the objective lens in the direction of the optical axis and in a direction perpendicular to the optical axis is disposed; a support base in which generating member for generating the driving forces is disposed; an elastic member W extended from the support base and fixed to the lens frame for swingably supporting the lens in a cantilevered manner; and a tilting member for inclining the optical axis of the objective lens with respect to the support base by tilting the lens frame.

Abstract: A method for automatically controlling output power of a pick-up head. When output power of a pick-up head is to be changed, a first switch is utilized to connect a first input port of a comparator circuit to a supply source, and a second switch is utilized to connect a first signal source to a driver circuit such that the driver circuit will control the output power according to a first signal. When voltage drop between the first input port and a output port of the comparator circuit stabilizes, the first switch is utilized to connect the first input port to a sensor, and the second switch is utilized to connect the output port and the driver circuit such that the driver circuit will control the output power according to a comparative signal.

Abstract: The present invention relates to an information recording apparatus, an information recording method, an information recording medium, an information reproducing apparatus and an information reproducing method by which in the case in which the present invention is applied to an optical disk system by, for example, a compact disk or the like and data or the like related to copyright is recorded by partial change of a pit shape or the like, the data can be reproduced with certainty without repeatedly recording the data. According to the present invention, with regard to a defect having a size by which at least main data can be reproduced correctly, 1 bit of sub-data SB is allocated to a pit row or the like having a predetermined length or more such that the sub-data SB can be reproduced correctly.

Abstract: When a wavelength of a first laser beam with which a first recording medium including a first recording layer is recorded and reproduced is indicated as ?1 (nm), a wavelength of a second laser beam with which a second recording medium including a second recording layer is recorded and reproduced as ?2 (nm), the relationship between the wavelength ?1 and the wavelength ?2 is set to be expressed by 10?|?1??2|?120. The first recording layer has a light absorptance ratio of at least 1.0 with respect to the wavelength ?1. The light transmittance of the first recording medium with respect to the wavelength ?2 is set to be at least 30 in both the cases where the recording layer is in a crystal state and in an amorphous state. In order to record and reproduce the optical multilayer disk with the above-mentioned characteristics, a multiwavelength light source with the following configuration is used.

Abstract: The present invention relates to an information recording apparatus, an information recording method, an information recording medium, an information reproducing apparatus and an information reproducing method by which in the case in which the present invention is applied to an optical disk system by, for example, a compact disk or the like and data or the like related to copyright is recorded by partial change of a pit shape or the like, the data can be reproduced with certainty without repeatedly recording the data. According to the present invention, with regard to a defect having a size by which at least main data can be reproduced correctly, 1 bit of sub-data SB is allocated to a pit row or the like having a predetermined length or more such that the sub-data SB can be reproduced correctly.

Abstract: A recording medium comprises a substrate and a recording layer overlaid on the substrate. The recording layer comprises a material, which has properties such that, when recording light having a predetermined wavelength ?1 is irradiated to the material, the material is capable of being caused to change into a fluorescent material and such that, when excitation light having a wavelength ?2 is then irradiated to the thus formed fluorescent material, the fluorescent material is capable of being caused to produce fluorescence. The wavelength ?1 of the recording light and the wavelength ?2 of the excitation light may be identical or different. The substrate may be constituted of a material having properties such that, when the excitation light is irradiated to the material, the material does not produce fluorescence having a wavelength identical with the wavelength of the fluorescence produced by the fluorescent material.

Abstract: When information is reproduced in an optical disk of high recording density or of low recording density, a main beam and sub-beams are emitted onto adjacent tracks. The main beam has a shape longer in a direction perpendicular to the tracks. When the optical disk of high recording density is reproduced, cross talk components from adjacent tracks included in signals reproduced from reflection light of the main beam are canceled by using signals reproduced from reflection lights of the sub-beams. When the optical disk of low recording density is reproduced, information is reproduced with a beam. Thus, two types of optical disks can be reproduced with a simple structure in a compatible way. In the cross talk canceling, discrimination marks formed along the tracks at constant distances are reproduced, and a time difference between the main beam and the sub-beams is corrected precisely by using track jump and detection of discrimination marks.

Abstract: An optical disk device which performs data recording and reproduction with regard to an optical disk on which pre-pit information for specifying an address is formed. An optical disk is irradiated with a laser beam and return light from the optical disk is detected by two photodetectors which are disposed in the radial direction. After the levels of two signals from the photodetectors are limited, a difference between these signals is calculated. Due to the limitation of the levels, noise during the recording power period is removed so that pre-pit information during the reproducing power period, namely during the space period, is extracted. Further, by calculating a difference between the two signals from the photodetectors, pre-pit information during the recording power period is extracted.

Abstract: The present invention relates to a modulated signal generator capable of carrying out signal processing at a higher speed or capable of supporting a special format and a new format with ease. A modulation processing storing unit 130 has a modulation processing program required for producing an optical disc master 320 stored therein in advance. Information data recorded in an master optical disc 310 is reproduced by an information reproducing unit 110 and is outputted to a modulation controller 120. The modulation controller 120 carries out the signal modulation processing onto the reproduced information data in accordance with the signal modulation processing program so as to generate a data stream and stores the data stream in a modulated information storing unit 140 as necessary.

Abstract: In an objective lens driving device for an optical disk, a plurality of elastic supporting members supporting an objective lens have bent portions bent approximately in the focus direction and are arranged in parallel approximately in the focus direction to cause expansion/contraction of the elastic supporting members in the direction offsetting a moment M. With this structure, a tilt correction method of the movable portion, a tilt correction method of an objective lens for an optical disk, and an objective lens driving device for an optical disk can be provided capable of reducing the size of the movable portion, minimizing tilt of the objective lens in the focus direction to provide enhanced optical performance, and restraining a resonance peak by the elastic supporting members.

Abstract: According to the present invention, it is intended that the recording can be executed normally even against small vibrations to which a servo error signal detecting circuit cannot respond. A recording apparatus according to the present invention includes an optical head (12) for receiving a reflected laser beam (LREF) obtained when a laser beam (LIRR) is irradiated on a CD-R (10). This recording apparatus further includes a gate circuit (31) to which an output signal (SRD) of the optical head (12) is supplied and a level comparing circuit (34) for comparing a value of an output signal (DTAU) of this gate circuit (31) with a predetermined reference value (DTH). Upon recording, the gate circuit (31) is controlled in such a manner that a signal of a predetermined period ? may be outputted from the output signal (SRD) supplied from the optical head (12) to the gate circuit (31) as the output signal (DTAU).