Abstract: An optical recording medium and a recording/reproducing method therefor to stably and accurately address a basic recording and/or reproducing unit (a sector or a frame) when a track pitch is decreased for recording of a large capacity of data. The general information (e.g., a variable frequency oscillator, a sector number, a sector type, and error detection information) of a corresponding sector is read from a header, which has physical pits between adjacent land and/or groove tracks, before recording or reproducing. The arrangement of the header is in the form of physical pits, with a sector structure where 2-kilobyte minimum recording units are included in a user area within a basic recording unit of 4 kilobytes, which thereby reduces overhead and facilitates the generation of a servo control signal.

Abstract: A method for discriminating a type of an optical recording medium including the steps of: checking a disk is mounted; performing a focus-searching by rotating a mounted disk by means of a recording/reproducing system for a specific disk to detect a focus search level, and identifying whether the currently mounted disk belongs to a specific type on the basis of the detected focus-search level; detecting an RF level and/or a focus error signal level by rotating the mounted disk, and identifying a type of the currently mounted disk on the basis of the detected signal.

Abstract: P-polarized parallel rays are irradiated on a magneto-optical disk 1 and reflected. The reflected light is reflected by a first beam splitter 14 and supplied to a reproduced signal detection system 20. This reflected light is supplied to a light shading plate 21, and a p-polarized component is transmitted at a transmittance of substantially 100% and an s-polarized component is transmitted at a transmittance of substantially 0%, i.e., reflected or absorbed so as to be shaded, in the area of a polarization film 21b. The light transmitted through the light shading plate 21 incides on a polarization beam splitter 19 where it is split into the p-polarized component and s-polarized component, and a reproduced signal is detected by differential detection.

Abstract: An optical information recording and reproducing apparatus capable of recording and reproducing information data accurately with respect to an optical recording medium. The optical information recording and reproducing apparatus includes an aberration correction part which corrects aberration of the optical system. The apparatus determines whether or not an aberration correction by the aberration correction part is completed based on the signal level read from the optical recording medium, while changing a spherical aberration correction amount of the aberration correction part. The apparatus commences a recording operation or a reproducing operation of the optical information recording and reproducing apparatus if it is determined that the aberration correction was completed.

Abstract: It is intended to perform a focusing control reliably in near-field recording in, for example, an exposing apparatus that performs exposure of an original disc by near-field recording (NFR). An objective lens is moved based on a light quantity detection result of an interference light beam that is produced by interference between light reflected by a disc-shaped recording medium and light reflected by the exit surface of the objective lens.

Abstract: This invention provides an optical recording medium having a structure in which a plurality of recording layers are stacked, and a reproducing method and apparatus for the medium. As an interlayer interposed between first and second recording layers, this invention uses a layer which guides converged light irradiating the first recording layer to the second recording layer such that the beam diameter on the second recording layer is substantially equal to the beam diameter on the first recording layer.

Abstract: An optical disc recording apparatus records a digital content onto an optical disc so that the perfect copying of the digital content is difficult without proper authorization. The optical disc recording apparatus includes a formatter for generating a channel signal corresponding to primary digital information, a secret key storing unit for prestoring secondary digital information, a pseudo random number generator for generating a pseudo random number series, an XOR for logically inverting the pseudo random number series according to each bit of the secondary digital information, a PE modulator for generating a PE modulation signal according to the logically inverted pseudo random number series, a phase modulator for modulating the phase of each edge of the channel signal by a fixed slight time according to the value of the PE modulation signal, and a recording channel for forming recording marks on a DVD according to the modulated channel signal.

Abstract: An optical pickup device includes a double-source built-in semiconductor laser for emitting light of a first wavelength and light of a second wavelength, a first divergence modifying device for modifying the diverging rate of emitted light from the double-source built-in semiconductor laser to a first diverging rate, a second divergence modifying device for modifying the diverging rate of a part of transmitted light through the first divergence modifying device to a second diverging rate, and an objective lens which focalizes the light with the first wavelength modified to the first diverging rate by the first divergence modifying device onto a first optical disc, and focalizes the light with the second wavelength modified to the second diverging rate by the first and second divergence modifying devices onto a second optical disc.

Abstract: An optical head comprising an objective lens having a large numerical aperture of 0.8 or more. The head further comprises a light source and an aberration-correcting lens group. To correct spherical aberration due to the manufacturing errors of an optical recording medium and lenses, to sufficiently correct chromatic aberration due to the use of a short-wavelength semiconductor laser and to correct aberration resulting from the use of the same optical system for light beams of different wavelengths, the objective lens 20 is composed of two more lenses and has a numerical aperture of 0.80 or more and the aberration-correcting lens group 1 is composed of a positive lens group 3 and a negative lens group 2. The space between the positive lens group 3 and negative lens group 2 of the aberration-correcting lens group 1 is changed, thereby to correct spherical aberration occurring at each optical surface of the optical system.

Abstract: A method and an apparatus for measuring eccentricity of the tracks of a disk. The apparatus includes a spindle for driving a turntable carrying a disk, an angle detecting device for detecting the angle of rotation of the spindle, a reproducing head for reproducing information from the disk, a pair of servos for controlling the tracking operation of the head, an eccentricity measuring device for measuring the extent of eccentricity from a signal reproduced by the head, an error detecting device for obtaining a tracking error signal by turning on the tracking servos, and an operation device for determining the direction of eccentricity from the angle of rotation and the tracking error signal, determining a vector quantity of the eccentricity of the tracks from the extent of eccentricity and the direction of eccentricity, and for performing a vector operation to determine the quantity of eccentricity of the tracks.

Abstract: An object of this invention is to provide a reproducing method and apparatus capable of facilitating a processing operation for permitting a write into a temporal memory means by reading data from a recording medium driven at a variable driving speed, permitting the write into a temporal memory means according to a signal reproduced from the recording medium and if there is a permission for the write in a period generated at a predetermined cycle and allowing the write into the temporal memory means, writing the data read to the temporal memory means.

Abstract: There is disclosed a storage apparatus which is of a system of utilizing a polarized state change by Kerr effect to read information from a storage medium and which easily and precisely performs adjustment to compensate for a phase deviation between both P, S polarized components attributed to an optical system. Phase plates 500, 510 are disposed between a fixed optical section 200 and a movable optical section 190 and the inclination angles of the phase plates are adjusted.

Abstract: The present invention provides a method and system for providing timing adjustments to perform reliable optical recording at high speeds. The present invention includes performing a timing adjustment in a coarse increment to a write control signal using a clock with a cycle less than T, where T is a fundamental unit of time for a data mark; and performing a timing adjustment in a fine increment to the write control signal using a time delay technique. The method and system in accordance with the present invention provides a write control logic which allows for multiple levels of time adjustment for each type of mark. In the preferred embodiment, a dual level timing adjustment technique is provided. The first level provides coarse timing adjustments using a clock with a cycle less than T and parameters to control the power level and time duration of each mark. The second level provides fine timing adjustments using time delay techniques.

Abstract: A method for optical data recording and readout includes scanning a blank region of an optical recording medium while recording a data band including a plurality of adjacent data tracks; synchronizing the recording on all tracks to a common data clock; and simultaneously recording control tracks with the band of data tracks, each control track having a well-defined track center and a repetitive pattern of marks that is synchronized to the data clock. The method further includes optically sensing the cross-scan positions and clock offsets of at least one control track on either side of the data band; interpolating between the control track cross-scan positions to predict the cross-scan positions of each data track and compensate for magnification errors; interpolating between the control track clock offsets to predict the clock offset of each data track and compensate for skew errors; and simultaneously reading and decoding information recorded on all tracks of the data band.

Abstract: An optical disk recording apparatus includes an input device that receives an input digital audio signal sampled by a predetermined sampling rate, an external reference clock pulse generator that reproduces a first reference clock pulse on the basis of the input digital audio signal, an internal reference clock pulse generator that generates a second reference clock pulse, a buffer memory that stores the input digital audio signal therein in synchronism with the first reference clock pulses, and that reads out a stored input digital audio signal therefrom in shynchronism with the second reference clock pulses, an operator operable by a user to give an instruction as to whether an inter-music-piece blank signal is to be recorded or not, the inter-music piece blank signal being capable of recording onto an optical disk before recording of the input digital audio signal read from the buffer memory, and a controller that, on the basis of the instruction from the operator, when the inter-music piece blank signal i

Abstract: The present invention provides a method and system for window realignment to correct the data frame boundaries of data from an optical media. The present invention includes: determining if a sync pattern for a data frame is within a sync window; opening an extended sync window, if the sync pattern for the data frame is not within the sync window; determining if the sync pattern for the data frame is within the extended sync window; and realigning the sync window to the sync pattern in the extended sync window, if the sync pattern is within the extended sync window. The present invention utilizes an extended sync window to realign the sync window when the number of missing sync patterns in a data stream has exceeded a threshold number. In the preferred embodiment, the width of the extended sync window and the threshold number are programmable. In this manner, the sync window can be realigned before shifting of the data renders the data uncorrectable.

Abstract: The present invention provides a method and system for servo control in an optical drive. The method includes initiating an execution of a multiplier and accumulator controller (MAC) by a processor; and automatically calculating a transfer function by the MAC based upon a sample servo data. The present invention provides a servo control system which utilizes a MAC which is directly linked to the sample servo data. When a processor commands the MAC to execute, the MAC receives the sample servo directly from an Analog-to-Digital Converter (ADC); retrieves the corresponding accumulated sample servo data from a memory; calculates the transfer function; and stores the results back into the memory. The processor then accesses the memory to retrieve the result. Because the MAC is able to calculate the transfer function with minimal intervention from the processor, significant processing resources and time are saved.

Abstract: A CLV optical disc capable of recording the information with a constant linear velocity. In the CLV optical disc, plural lines of specified track exist in the predetermined data area, railroad length of the tracks is integer times of the length of a sector, the length of the sector on the specified tracks is 2×&pgr;×N times of a track pitch, the number N is a positive integral number, and head positions of the specified tracks are lined up on a predetermined radius line A-A′ at equal track intervals. Fixed-length track marks are arranged at equal physical length intervals along the information track formed in the state of a spiral. The track position information is obtained by detecting the track marks of the present and adjacent tracks. The CLV optical disc medium recording/reproducing apparatus can perform the seeking operation by use of the CPU and the other relevant units regardless of the operation of controlling the disc revolution number.

Abstract: The present invention relates to an apparatus for reading from and/or writing to optical recording media with optical scanner, light source, focusing means, tilting-detection device and tilting-compensation device. The object of the invention is to propose an apparatus and a method, which enables optimum compensation of tilting using as few apparatus functions as possible. This is achieved according to the invention by using a tilting-detection device comprising an optical grating, a detector element, a control device for controlling light source and the focusing means and a control device controlling for the tilting-compensation device.

Abstract: To implement light quantity monitoring with high frequency responsivity and correction of astigmatic differences of a semiconductor laser with a simple configuration with fewer parts. Of the output from a semiconductor laser light source, a peripheral component is entered by a light reflection element into an anterior light monitoring photodetector formed in the vicinity of a semiconductor laser light source. Furthermore, the surface of the reflection sphere of the light reflection element is anamorphic, and thus condensed to an appropriate size on the photodetector without being focused, providing high frequency responsivity. Furthermore, the light reflection element is inclined at a predetermined angle to cancel out astigmatic differences of the optical semiconductor laser light source. In addition, the photodetector is placed so that reflected light is bent by an inclination of the light reflection element, reducing the amount of parallel displacement during adjustment of the light reflection element.