Abstract: A method for verifying sectors on an optical disc is provided. The method includes writing user data to unverified sectors of the optical disc and verifying the sectors of the optical disc with the user data. The sectors of the optical disc are verified by reading the user data on the unverified sectors of the optical disc and comparing the user data read from the unverified sectors of the optical disc with user data stored on a system buffer. The sectors of the optical disc are verified to determine whether any one of the unverified sectors having user data is defective. Also, the verifying of the unverified sectors establishes verified sectors having user data. The sectors of the optical disc that have been verified are tracked with a bitmap that is continually updated as the sectors are verified.

Abstract: A photodetector IC in an optical head device includes a four-segment photodetector (30) and a push-pull signal generator (33). The push-pull signal generator (33) generates a sum signal (A+D) of radially outer photodetector segments and a sum signal (B+C) of radially inner photodetector segments. The sum signal (B+C) is multiplied with a coefficient t entered from outside and a signal ((A+D)?t×(B+C)) is generated by a subtractor. The signal generated is output as a radial push-pull signal (R-PP). The coefficient t is a value corresponding to the ratio of the light volume of the outer rim side photodetector segments and the light volume of the inner rim side photodetector segments.

Abstract: A data reproducing apparatus is disclosed. The data reproducing apparatus comprising reproducing means for reading data from a recording medium, and data varying means for varying the data that is read from the recording medium whenever the data is read therefrom or once every a plurality of times it is read therefrom.

Abstract: A method is provided for producing a data storage medium by recording disc information on the data storage medium.

Abstract: A data storage medium is provided on which data is to be recorded by modulating the data to generate a plurality of recording modulation codes and irradiating a pulse-like light beam to the data storage medium, so that a plurality of recording marks and spaces which have lengths corresponding to the plurality of recording modulation codes are formed on the data storage medium. The data storage medium comprises a disc information area that includes a region on which at least one of an irradiation information of the light beam to form the recording marks and a constitution information of the recording mark is to be recorded. At least two of the plurality of recording marks are formed by the light beam emitted according to a recording pulse train.

Abstract: A method is provided for producing a data storage medium by recording disc information on the data storage medium.

Abstract: A data storage medium is provided on which data is to be recorded by modulating the data to generate a plurality of recording modulation codes and irradiating a pulse-like light beam to the data storage medium, so that a plurality of recording marks and spaces which have lengths corresponding to the plurality of recording modulation codes are formed on the data storage medium. At least two of the plurality of recording marks are formed by the light beam emitted according to a recording pulse train. The recording pulse train comprising a first pulse which is disposed at a front and forms a leading edge of the recording mark, a last pulse which is disposed at a backend and forms a trailing edge of the recording mark, and a multi-pulse train which is disposed between the first pulse and the last pulse and forms a center of the recording mark. The multi-pulse train has a pulse period longer than T which represents a reference period of the recording modulation code.

Abstract: The optical data recording method comprising the steps of: modulating data to be recorded, to generate a plurality of recording modulation codes; and emitting a pulse-like light beam to an optical disc, so that a plurality of recording marks and spaces which have lengths corresponding to the plurality of recording modulation codes are formed on the optical disc. In the optical data recording method, at least two of the plurality of recording marks comprises: a first pulse which is disposed at a front and forms a leading edge of the recording mark, a last pulse which is disposed at a backend and forms a trailing edge of the recording mark, and a multi-pulse train which is disposed between the first pulse and the last pulse and forms a center of the recording mark. The multi-pulse train has a pulse period longer than T which represents a reference period of the recording modulation code.

Abstract: The present invention provides an optical disk control device that can perform focus pulling in a short time for a target information surface of an optical disk having a plurality of information surfaces. An objective lens (23) is moved toward an optical disk (1) having a plurality of information surfaces (1A, 1B) by the output signal of a driving signal generating circuit (42B), passage of an initial focused focal position is detected by a focal point passage detecting circuit (44), and when the objective lens moves past that position only a predetermined amount closer to the optical disk, an n-rotation delay circuit (70) outputs a reversal instruction f. After changing directions and moving the objective lens away from the optical disk, a focus pulling-in circuit (32B) switches a signal “a” that is output to an actuator driving circuit (21) from the output signal of the driving signal generating circuit to the output signal of the control circuit, activates a control circuit and performs focus pulling-in.

Abstract: A rewritable optical disk apparatus, optical information recording and reproducing apparatus or the like is allowed to automatically and properly adjust the optical system to the optimum focal condition regardless of the readout signal detector's positional error and the residual aberration in the optical system. The spherical aberration and defocus are coarsely adjusted using the amplitude (PP amplitude) of the tracking error signal and then finely adjusted using the amplitude (RF amplitude) of the readout signal. Since the spherical aberration can properly be adjusted, it is possible to raise the reliability of the readout signal.

Abstract: The present invention provides an optical disk apparatus in which a first, second, third, and fourth optical disks are selectively installed, the first and second optical disks having different recording film characteristics and both having a single-layer recording layer, the third and fourth optical disks having different recording film characteristics and both having a double-layer recording layer. A control section determines which of the first to fourth optical disks has been installed, on the basis of the level of a reproduction signal from an optical head. Recording media serving as the optical disks are formed so that the light reflectances of a single-layer L-H medium in an initialized state, an L0 layer of a double-layer H-L medium in the initialized state, and an L0 layer of a double-layer L-H medium in an uninitialized state do not overlap the light reflectance of a single-layer H-L medium in the initialized state.

Abstract: A method of recording data optically to an optical disk having a plurality of sectors, in which each sector has a region to be recorded with data, the data is recorded in units of blocks, and the block includes a predetermined number of sectors and is a data unit including error correction codes. In recording data related to a content by dividing and recording the data in a plurality of sectors continuously, dummy data to be used for extracting a clock in phase lock loop (PLL) for data reproduction is recorded on a region adjacent before a sector from which data recording is started. The data related to the contents is recorded on sectors following the region recorded with the dummy data.

Abstract: An optical pickup device capable of correcting an off-tracking which is ascribable to a phase shift of a differential push-pull signal waveform, even when an optical disk or an objective lens is tilted along a radial direction of the optical disk, so that stable tracking control can be performed; and, an optical disk apparatus comprising such an optical pickup device.

Abstract: A method of recording data optically to an optical disk having a plurality of sectors, in which each sector has a region to be recorded with data, the data is recorded in units of blocks, and the block includes a predetermined number of sectors and is a data unit including error correction codes. In recording data related to a content by dividing and recording the data in a plurality of sectors continuously, dummy data to be used for extracting a clock in phase lock loop (PLL) for data reproduction is recorded on a region adjacent before a sector from which data recording is started. The data related to the contents is recorded on sectors following the region recorded with the dummy data.

Abstract: A method of recording data optically to an optical disk having a plurality of sectors, in which each sector has a region to be recorded with data, the data is recorded in units of blocks, and the block includes a predetermined number of sectors and is a data unit including error correction codes. In recording data related to a content by dividing and recording the data in a plurality of sectors continuously, dummy data to be used for extracting a clock in phase lock loop (PLL) for data reproduction is recorded on a region adjacent before a sector from which data recording is started. The data related to the contents is recorded on sectors following the region recorded with the dummy data.

Abstract: A method and device for measuring the tilt in an optical disc drive (1) is disclosed. The optical disc drive (1) comprises two lasers (31, 41) generating two laser beams (32, 42) having mutually different optical characteristics. One of these laser beams (32) is continuously ON, and is used for writing or reading data to or form the disc. The other laser beam (42) is repeatedly switched ON and OFF. Tilt is measured by comparing a normalized error signal (RES(ON)) during the ON-phase (TON) with a normalized error signal (RES(OFF)) during the OFF-phase.

Abstract: An information recording medium 1 at least comprises a substrate 13 having a microscopic pattern 20, which is constituted by a shape of continuous substance of approximately parallel grooves formed with a groove section G and a land section L alternately, a recording layer 12 formed on the microscopic pattern 20 and a light transmission layer 11 formed on the recording layer. The microscopic pattern 20 is formed so as to satisfy a relation of P<?<NA and a thickness of the light transmission layer 11 is within a range of 0.07 to 0.12 mm, wherein P is a pitch of the groove section G or the land section L, ? is a wavelength of reproducing light beam and NA is a numerical aperture of an objective lens. Further, there provided an information recording medium, which is improved in cross erase and recorded in high density, and a reproducing apparatus and a recording apparatus for the information recording medium.

Abstract: A device has a head for recording information by writing marks in a track on a record carrier via a beam of radiation. The radiation is controlled to write the marks having a main mark intensity and a mark length within a predefined range of mark lengths. Further, secondary marks are recorded in the same part of the track. The secondary marks have a secondary mark intensity that is substantially different from the main mark intensity and a length substantially longer than mark lengths in the predefined range. Furthermore, a record carrier, method of recording and a read device are described.

Abstract: There is provided a disk recording apparatus capable of minimizing a servo error and recording in the last zone at the maximum one of the recording speeds specified in the apparatus or disk recording medium even if the disk recording medium is in poor condition. At any position during disk activation, an axial-run-out and eccentricity measuring circuit (115) measures the eccentricity of the disk recording medium. A CPU (101) calculates the upper-limit rotation speed from the measurement, divides the recording area into zones in such a manner that the disk recording medium rotates at speeds lower or equal to the upper-limit rotation speed, determines the maximum one of the recording speeds specified in the apparatus and supported by the disk recording medium for each zone, sets a zone CLV table, and stores the table in a RAM (102). Then, the recording speeds are changed at zone boundaries according to the zone CLV table set based on the upper-limit rotation speeds calculated from the eccentricities.

Abstract: A record carrier stores audio data as audio tracks in audio files and associated management information. To avoid annoying clicks at the end or beginning of live recorded audio tracks, if those tracks are not played back seamlessly but by suppressing of introductory audio data stored in the pre-track, a seamless playback information is provided in the management information indicating if an audio track has to be played back seamlessly after a particular other audio track.