Abstract: In a recordable data storage medium on which property data was recorded after having been modulated and on which data that is decodable by a cryptographic key to be generated from the property data was recorded, the property data was preferably modulated by a different method from that applied to a read-only data storage medium. Then, an optical disc drive, having no ability to distinguish the recordable data storage medium from the read-only data storage medium, cannot read the recordable data storage medium. Consequently, a greater number of drives should be equipped with the function of recognizing the type of a given data storage medium and the copyright protection function should be consolidated.

Abstract: In an optical recording method and apparatus of the present invention, a driving power is applied to a light source to control emission of a light beam to a recording layer of an optical storage medium, the driving power including a sequence of mark and space portions, each mark portion having a pulse width that corresponds to a multiple of a period T of a write clock. A multi-pulse waveform of each mark portion of the driving power includes a front-end portion, a multi-pulse portion and a tail-end portion, the front-end portion having a first pulse width t1 with a high-power write level Pw and starting from a middle-power erase level Pe, the multi-pulse portion including write pulses each having a second pulse width t2 with the write level Pw and a third pulse width t3 with a low-power base level Pb, the multi-pulse portion having a duty ratio z=t2/(t2+t3), and the tail-end portion having a fourth pulse width t4 with the base level Pb and ending at the erase level Pe.

Abstract: A disk recording medium which can implement a recording method having a high degree of reliability for additional information is disclosed. The disk recording medium has a recording and reproduction region into and from which first data can be recorded and reproduced in accordance with a rewritable or write-once-read-many recording method and from which second data recorded in the form of wobbling of a groove can be reproduced. The second data includes address information and additional information. The additional information of the second data is coded in accordance with a first error correction method, and the coded additional information and the address information are recorded in a state coded in accordance with a second error correction method.

Abstract: The present invention relates to an optical pickup, and more particularly to an optical pickup comprising an optical modulator for reflecting and diffracting an incident light beam to generate multiple beams, and the optical pickup simultaneously reads a plurality of data bits using multiple beams at the time of reading optical disc information, thus promptly processing optical disk information, thereby the optical pickup of the present invention can cope with various types of optical disk media using light beams with different wavelengths.

Abstract: The present invention aims to enable revision of additional information buried in contents data with less burden on hardware. For this purpose, a predetermined amount of inputted contents data is temporarily stored in buffer means, the additional information buried in the contents data being detected from the contents data temporarily stored in the buffer means, the contents of the detected additional information being estimated, the contents data being made to be recorded in a predetermined medium when estimated that the contents data can be recorded, and the contents data being made not to be recorded in the medium when estimated that the contents data must not be recorded. In addition, when estimated that revision of the additional information is necessary, the relevant part of data stored in the buffer means is revised while it is being stored in the buffer means.

Abstract: To provide a light receiving device, a light detecting device, and an optical signal reproducing device each of which allows one to perform many different computations in detecting aberration amounts and focus error quantities without requiring exact position relations between laser light to be received and light receiving elements, and between the light receiving elements. First and second light receiving elements 43+ and 43? are used which receive condensed light at positions equidistantly spaced from an focal point X before and after the light images, respectively.

Abstract: A security control method for an optical disk drive comprises a security information reading step and a security information-determining step. In the security information reading step, security information associated with data to be read is read from a plurality of locations on an optical disk. In the security information-determining step, correct security information is determined by comparing fragments of the security information read from the plurality of locations and then by selecting a security information fragment with the highest frequency. The correct security information is used in processing of the data to be read.

Abstract: A carriage servo apparatus according to the present invention comprises: a carriage for supporting a pickup that records or reproduces information relevant to an information recording face; and a carriage motor for moving the carriage in a direction parallel to the information recording face based on a motor drive signal. This carriage servo apparatus further comprises a microcomputer for detecting a minimum value of a motor drive signal required for moving the carriage from its still state, and setting a motor drive signal when recording or reproducing information, based on the detected minimum value.

Abstract: In a process of braking an spindle motor, a frequency of a read clock signal synchronized with an RF signal output from an RF amplifier is measured as a first frequency by a braking control circuit. A brake is then applied to the spindle motor for a predetermined time. Thereafter, the frequency of the read clock signal is measured as a second frequency. Next, the braking time is calculated on the basis of: a frequency difference obtained by subtracting the second frequency from the first frequency; the first frequency; and a measuring time from the timing when the first frequency is measured to the timing when the second frequency is measured.

Abstract: A dynamic compensation device for radio frequency ripple signals of an optical storage system is disclosed. The device is composed of a radio frequency ripple signal process circuit, a radio frequency signal process circuit, a radio frequency signal peak detector, a first analog to digital converter, a second analog to digital converter, a defect detector, and a fingerprint detector. The drop-out of the central level of the radio frequency ripple signal is eliminated, and the track cross waveform is prevented from being damaged.

Abstract: If the number of retries made before data is read successfully reaches or exceeds a predetermined number, the data is saved in spare sectors SS and then data sectors DS which originally stored the data are overwritten. Furthermore, both when data is saved in spare sectors SS and when data is written over data sectors DS, appropriate pointer information in RDM table stored in a reserved area RA including a nonvolatile memory is updated as required.

Abstract: A thickness servo system using optical aberrations is provided. In this servo system, a photodetector detects an aberration amount corresponding to thickness irregularity, and a thickness irregularity correction section operates to minimize the detected aberration amount. The thickness irregularity of a transparent layer can also be calculated from the detected aberration amount.

Abstract: A record carrier carries a stereo signal and a data signal which includes a first data portion and a remaining data portion. A first channel on the record carrier includes a composite signal which is obtained by combining the stereo signal and the first data portion. A second channel on the record carrier includes the remaining data portion of the data signal. The stereo signal and the data signal are recorded to and reproduced from the record carrier using a recording apparatus and a reproducing apparatus.

Abstract: A light-converging optical system has an objective lens arranged at a position to be opposite to an optical information recording medium and including at least one plastic lens, and an aberration correcting element provided on an optical path between the light source and the objective lens and structured by two groups of a positive lens and a negative lens both being a plastic lens. At least one of the positive lens and the negative lens has at least one diffractive surface on which a diffractive structure is formed and a total paraxial power of the aberration correcting element has a temperature dependency satisfying a formula of: PT1<PT0<PT2, or PT1>PT0>PT2, where PT0, PT1 and PT2 are the total paraxial power (mm?1) of the aberration correcting element under the temperature of 25° C., ?5° C. and 55° C. respectively.

Abstract: An aberration correcting unit is provided for correcting an aberration of a light beam radiated onto an object to be detected and then reflected from the object. This unit comprises an aberration correcting device comprising a first corrector configured to correct the aberration of the light beam radiated onto the object; and a second corrector configured to correct the aberration of the light beam reflected from the object and to divide the reflected light beam into a plurality of light beams. The aberration correcting unit further comprises a first driver configured to drive the first corrector and a second driver configured to drive the second corrector.

Abstract: The invention presents systems and methods for initializing the phase-change layer of an optical medium. The methods include alternately quenching the phase-change material into amorphous states and crystallization states in a single pass of an optical head past the optical medium. The systems include one or more light sources that generate at least two amorphous melt regions and at least two crystallization regions in the optical medium.

Abstract: A multi-layered information recording medium comprising a plurality of recording layers, a user data area for recording user data, provided in at least two of the plurality of recording layers, and a defect list storing area for storing a defect list. When at least one defective area is detected in the user data area, the defect list is used to manage the at least one defective area.

Abstract: In a PLL circuit, a phase error of a reproduced signal is extracted in either a way based on a zero-cross timing or a way based on a self-running timing. A decision is made as to whether the reproduced signal is in a continuous-wave interval where an inversion period of the reproduced signal remains constant or in a random-wave interval where the inversion period of the reproduced signal varies at random. When the reproduced signal is in a continuous-wave interval, a phase error is extracted on the self-running-timing basis. When the reproduced signal is in a random-wave interval, a phase error is extracted on the zero-cross-timing basis. A continuous-wave interval may be replaced by a specified-pattern repetition interval where the inversion period of the reproduced signal changes in accordance with a repetition of a specified pattern.

Abstract: The present invention relates to a method and a circuit for recovering information contained in a wobbled track on 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. In order to adjust the weighting factors, the data signal component in the wobble signal is linked to a disturbance signal from a disturbance signal generator.

Abstract: An apparatus to generate a seek direction detecting signal for an optical pickup to determine a position of a center of an optical spot focused on an optical disk relative to a center of a track, which focuses a main beam on a first optical detector and a sub-beam having a predetermined aberration in a radial direction on a second optical detector using a light dividing unit. The second optical detector has an inner and an outer pair of light receiving portions arranged along the radial direction, the inner pair being between the outer pair. A signal processing portion includes a first signal processing portion to detect a track error signal from signals output from the first optical detector, and a second signal processing portion to generate the seek direction detecting signal from signals detected by the second optical detector and the track error signal.