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 recording apparatus for performing information recording using formation of marks by focusing a first light with an objective lens at a given position in a recording layer included in an optical disc recording medium, includes: a rotation driving unit for rotating the optical disc recording medium; a focus servo control unit for condensing a second light which is different from the first light on a reflection film, and for controlling a position of the objective lens so that a focal position of the second light follows the reflection film; a recording position setting unit for setting an information recording position of the first light in a focus direction by changing the collimation of the first light; a surface wobbling amount estimating unit; and a surface wobbling estimation amount acquisition control unit for acquiring a surface wobbling estimation amount for each rotation angle within one revolution of the disc.

Abstract: An information recording medium having at least a read only area and a recording and reproducing area is composed of at least: a substrate; a recording layer formed on the substrate so as to record and reproduce information; and a light transmission layer having transparency formed on the recording layer. The information recording medium is further characterized in that a wobbling groove corresponding to the read only area and another wobbling groove corresponding to the recording and reproducing area is formed on the substrate without overlapping with each other, the recording and light transmitting layers are continuously adhered over at least two areas of the read only area and the recording and reproducing area, reflectivity of the recording layer is more than 5%, and a push-pull signal output T3 reproduced from the read only area and another push-pull signal output T4 reproduced from the recording and reproducing area before recording satisfies relations of T3?0.1, T4?0.1 and 1.5?T3/T4?0.5.

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.

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.

Abstract: A method and apparatus demodulate pre-formatted information embedded in an optical recording medium. The demodulation includes (a) receiving a wobble signal representing data symbols frequency-modulated on a carrier frequency, (b) generating a phase delta signal representing a phase difference between the wobble signal and a corresponding locked signal having the carrier frequency, (c) first sampling the phase delta signal at a data sampling interval to produce first values, (d) second sampling the phase delta signal at each halfway of the data sampling interval to generate second values, (e) determining, based on a difference between two successive second values, if the first sampling is performed at timing corresponding to an end of each data symbol, and (e) adjusting sampling timing of the first sampling towards the timing corresponding to each end of the data symbols, if the sampling timing does not corresponds to the end of each data symbol.

Abstract: An attenuation-amount adjusting circuit includes: a light irradiating unit that alternately irradiates a laser beam of a writing level and a laser beam of a readout level on an optical disk that has a groove formed by a wobble pattern and plural markers indicating physical positions in the groove; a light receiving unit that receives reflected light of the laser beam irradiated on the optical disk and converts the reflected light into a reproduction signal; and a writing-waveform attenuating unit that attenuates an amplitude level of a writing waveform corresponding to the reflected light of the laser beam of the writing level in the reproduction signal according to a position from a rising edge of the writing waveform.

Abstract: A wobble signal extraction circuit includes: an RF signal component acquiring portion for acquiring an RF signal component from at least one of first and second signals received by two light receiving portions, the two light receiving portions being obtained through division in halves with a direction along which each track of an optical recording medium extends as a boundary; a wobble signal acquiring portion for acquiring a wobble signal by subtracting the second signal from the first signal; an RF signal component binarizing portion for binarizing the RF signal component; a wobble signal binarizing portion for binarizing the wobble signal; and an exclusive OR arithmetically operating portion for arithmetically operating an exclusive OR of the binarized RF signal component and the binarized wobble signal; wherein balances between amplitudes of the first and second signals are detected based on an arithmetic operation result obtained in the exclusive OR arithmetically operating portion.

Abstract: An optical disc includes a read-only area having a first wobble, which is a data wobble formed in the read-only area for only reading, a readable/writable area having a second wobble, which is different from the data wobble, and a connection area between the read-only area and the readable/writable area having a third wobble having the same frequency as one of the first and second wobbles.

Abstract: When performing writing and/or reading of information to/from an optical disk provided with a wobble including time axis information, an occurrence of a reading error of the time axis information from the wobble is suppressed so that disabled reading of information from the optical disk and an occurrence of a writing error can be prevented. Evaluated parameters such as a CRC error rate of an ATIP signal, an FMDT jitter amount and a phase error between an ATIP synchronization signal and a frame synchronization signal of writing data are evaluated based on a range of set values. When the evaluated parameter is deviated from the range of set values, writing and reading speeds are changed, thereby increasing the reading accuracy of the wobble signal.

Abstract: An optical recording medium has a user data area and a lead-out area, wherein the user data area and the lead-out area each has grooves and lands formed thereon. Wobbles are formed on at least one lateral surface of grooves of the user data area and the lead-out area, and configured such that wobble characteristics are made different between the user data area and the lead-out area. Different types of wobbles are formed on the grooves of either the user data area or the lead-out area, thereby preventing an optical pickup that performs recording/reproduction from deviating from the user data area. Also, in a multi-layer optical recording medium, a whole area of a recording layer is configured to have a same condition, thereby preventing deterioration in reproduction and/or recording due to a difference in light power transmittance of another recording layer.

Abstract: An optical disk apparatus includes a signal detection unit which detects a signal corresponding to a wobbling guide groove formed on an optical disk, a timing signal generating unit which generates first and second timing signals in accordance with an amplitude level of the signal detected, a photodetector which detects reflective light from the optical disk, and a wobble signal generating unit which outputs as a wobble signal a signal which is amplified with a low gain amount by the first timing signal in a case where an arithmetic signal, which is generated for the wobble signal on the basis of a signal detected by the photodetector, is at a high amplification level, and outputs as the wobble signal a signal which is amplified with a high gain amount by the second timing signal in a case where the arithmetic signal is at a low amplification level.

Abstract: The invention device has amplitude correction means for generating, from a radial push-pull signal, a wobble signal which has been corrected such that the amplitude of a predetermined frequency component is kept substantially constant, and for outputting a magnification for correcting the amplitude of the predetermined frequency component as a gain control signal, and determination means for determining whether or not wobble exists based on a minimum value of the magnification indicated by the gain control signal.

Abstract: An optical disk apparatus to record data on an optical disk on which a wobble is formed, the optical disk apparatus including; a detection unit including a BPF which a signal obtained from a reflected light from an optical disk passes, the detection unit to detect a wobble signal from a wobble based on the signal passing the BPF; and a register to store an adjustment value for adjusting the BPF as a register value, so as to adjust the BPF based on each of register values obtained by changing the register value 1 LSB by 1 LSB; acquire an amplitude of the signal passing the BPF, the amplitude corresponding to each of the register values; identify one of the register values for the largest acquired amplitude; and adjust the BPF based on a value obtained by adding 1 LSB to the identified register value when data is recorded.

Abstract: The invention relates to a method for transmitting a write strategy to a laser driver, and to a pickup and an apparatus for writing to or reading from and writing to optical recording media using such method. According to the invention, the method has the steps of: transmitting an encrypted write strategy to the laser driver; and decrypting the transmitted write strategy with a decryption key stored in a first memory of the laser driver.

Abstract: A protective system and method for data write of an optical disk drive, which produces a pseudo synchronization signal for the optical disk drive to perform a write operation on an optical disk. First, a write target sector is determined and a current sector of the optical disk is monitored. Next, it is determined whether a wobble synchronization signal is possibly extracted from the optical disk; if not, the pseudo synchronization signal is produced. Finally, the optical drive is driven to perform the write operation on the optical disk.

Abstract: A high-density read-only optical disc, and an optical disc apparatus and method using the same. The apparatus and method record data on a lead-in area of a high-density read-only optical disc such as a BD-ROM (Blu-ray disc ROM (Read Only Memory)) in the form of pre-pit strings associated with an HFM (High-Frequency Modulated) groove applied to a BD-RW (Blu-ray Disc Rewritable). Moreover, the apparatus and method continuously apply the same tracking servo operation to an entire area of the same high-density read-only optical disc or rewritable optical disc. Therefore, the apparatus and method can simplify an algorithm for controlling a plurality of tracking servo operations, and avoid an increased size of the optical disc apparatus.

Abstract: An apparatus for reading subdivided information from an optical disk, which comprises a track groove and on which information is recorded along the track groove is disclosed. The apparatus includes an optical head, which irradiates the optical disk with light and generates an electric signal responsive to part of the light that has been reflected from the optical disk, read signal processing means for generating a wobble signal which has an amplitude changing with the wobble pattern from the electric signal, rise value acquiring means for sampling and holding an absolute gradient value of the wobble signal when the signal rises, fall value acquiring means for sampling and holding an absolute gradient value of the wobble signal when the signal falls, and subdivided information detecting means for determining the subdivided information by majority by comparing the values held by the rise and fall value acquiring means with each other.

Abstract: Disclosed is a TE signal polarity determining method, which includes: (a) obtaining a detection signal from an optical disc; (b) obtaining characteristics of the detection signal corresponding to different polarities of the TE signal; and (c) determining whether an original polarity of the TE signal should be changed or not according to the obtained characteristics.

Abstract: A recording medium includes a substrate having a microscopic pattern, which includes a shape of continuous substance of approximately parallel grooves formed with a convex shaped section and a concave shaped section alternating on a surface of the substrate. A recording layer is formed on the microscopic pattern and a light transmitting layer has a thickness of 0.05 mm to 0.12 mm formed on the recording layer. The microscopic pattern satisfies a relation of P??/NA, wherein P is a pitch of the convex shaped section, ? is a wavelength of a reproducing light beam and NA is a numerical aperture of an objective lens. The microscopic pattern also includes modulated address information formed on both side walls of the convex shaped section viewed from the light transmitting layer as a wobble, both the side walls being parallel to each other, and furthermore wherein the address information is modulated by the phase-shift keying modulation system.

Abstract: The invention provides an optical disc and a registering method for labeling on a label side of the optical disc. More particularly, the label side has a plurality of turns of wobbled grooves connected in series to form a spiral track. The turns of the wobbled grooves are then to provide a registering reference.

Abstract: The present disclosure can provide a method and an apparatus to correct wobble phase slip in an optical disc recording system during recording. The method of correcting a phase slip can include receiving a wobble signal of a first frequency, sampling the wobble signal to generate a sampled wobble signal, where the wobble signal is sampled at a second frequency that corresponds to a frequency of a sampling signal, comparing a phase of the sampled wobble signal with a phase of a controlled signal to generate a phase error, modifying the phase error by adding a phase bias, and adjusting the second frequency based on the modified phase error to reduce a magnitude of the modified phase error.

Abstract: A high-density read-only optical disc, and an optical disc apparatus and method using the same. The apparatus and method record data on a lead-in area of a high-density read-only optical disc such as a BD-ROM (Blu-ray disc ROM (Read Only Memory)) in the form of pre-pit strings associated with an HFM (High-Frequency Modulated) groove applied to a BD-RW (Blu-ray Disc Rewritable). Moreover, the apparatus and method continuously apply the same tracking servo operation to an entire area of the same high-density read-only optical disc or rewritable optical disc. Therefore, the apparatus and method can simplify an algorithm for controlling a plurality of tracking servo operations, and avoid an increased size of the optical disc apparatus.

Abstract: An optical pickup is disposed which irradiates a laser beam onto an optical disc where a guide groove having characteristics of thermal interference (heat discoloration) is spirally formed. The optical pickup irradiates the laser beam along the guide groove to conduct one of data recording in which pits indicating a data length are formed, and visible-image formation in which a part of the optical disc is discolored. The laser beam irradiation position is controlled so that the data recording is conducted with starting from the inner peripheral side of the optical disc, and the visible-image formation is conducted with starting from the outer peripheral side of the optical disc.

Abstract: The present invention is to provide an apparatus and method for calibrating focus balance in an optical disk drive. A focus servo unit controls a pick-up head to focus and read a mark for generating an RF signal. A jitter generator separates a jitter signal from the RF signal to form a jitter frequency. A focus balance unit compares sequential jitter frequencies to check the convergence and the goal, and determines the direction and variable of calibrating focus balance to generate an error signal. A compensator receives the error signal through the focus servo unit to control the pick-up head for calibrating focus balance.

Abstract: Plural grooves or lands formed in an information recording carrier include at least a wobbling region and data is recorded wobblingly in this wobbling region by phase shift modulation while recorded digitally with a single or multiple waves as a channel bit.

Abstract: In a method of and an apparatus for creating a reproduced wobble signal by subtracting an estimated crosstalk signal, expressed by a sine waveform having a frequency approximately equal to the meandering frequency of grooves, from an original wobble signal and recording or reproducing an information pattern at a predetermined position of an optical disc, a carrier signal, which is caused to correspond to the meandering of the groove by being subjected to phase synchronization, is assumed based on the reproduced wobble signal, a crosstalk remaining component is estimated from the amplitude and phase of the region, which meanders in approximately the same phase as the estimated carrier signal in the reproduced wobble signal, and from the amplitude and phase of the region which meanders according to a signal different from the estimated carrier signal, and the estimated crosstalk is updated to cancel the remaining component.

Abstract: The present invention relates to a device (1) for scanning an optical recording medium (3), comprising an optical unit (5) for reading data from and/or writing data to said recording medium (3) by scanning said recording medium (3) with a radiation beam (21), said radiation beam (21) being positioned on said recording medium (3) in response to a tracking error signal, a tracking means (7) for generating said tracking error signal and a position control means (11) for controlling a radial scanning position of said radiation beam (21) in respect to a track on said recording medium (3).

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: 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: An apparatus and a method for determining the type of an optical disk are provided. Firstly, an RF signal of the optical disk in an optical disk drive is read out. Next, a bandpass signal is extracted from the RF signal by a bandpass filter whose central frequency is a wobble frequency. Then, whether the bandpass signal corresponds to a wobble signal is determined. If so, the optical disk is a recordable optical disk; otherwise, the optical disk is a read-only optical disk.

Abstract: A tilt correcting apparatus makes a tilt correction in an information recording apparatus or the like capable of recording record information onto an information recording medium, on an information recording surface of which a track having a wobble is formed, by emitting laser light thereonto. The tilt correcting apparatus is provided with: a correcting device for changing an irradiation angle of the laser light; a controlling device for controlling the correcting device such that the irradiation angle is set to be each of a plurality of predetermined angles before the record information is recorded; a wobble detecting device for detecting a wobble signal corresponding to the wobble from a photo-detection signal of light from the track caused by the laser light; and a tilt determining device for determining an amount of tilt of the information recording surface, on the basis of the detected wobble signal.

Abstract: The present invention relates to a drive for accessing an optical record carrier (2) comprising means (4) for determining the type of record carrier, in particular for distinguishing a read-only record carrier from a recordable or rewritable record carrier having a wobbled groove in the lead-in zone, said means comprising: a DPD measuring unit (41) for measuring the differential phase detection (DPD) signal, a PP measuring unit (42) for measuring the push-pull (PP) signal in case no DPD signal could be measured, a wobble locking unit (43) for locking, in case a PP signal could be measured, to the wobble embedded in said wobbled groove using a first and/or a second polarity setting, and an indication unit (44) for generating a first indication signal indicating that the record carrier is a read-only record carrier if a DPD signal could be measured and that the record carrier is a recordable or rewritable record carrier if no DPD signal but a PP signal could be measured and if locking to the wobble has been suc

Abstract: An information recording medium is provided with a plurality of information recordable recording layers, and a spiral or concentric tracks are formed on each of the plurality of recording layers. At least a portion of each track has wobbles corresponding to a wobble signal that includes layer information for discriminating the recording layer formed with the track.

Abstract: An information recording medium having at least a read only area and a recording and reproducing area is composed of at least: a substrate; a recording layer formed on the substrate so as to record and reproduce information; and a light transmission layer having transparency formed on the recording layer. The information recording medium is further characterized in that a wobbling groove corresponding to the read only area and another wobbling groove corresponding to the recording and reproducing area is formed on the substrate without overlapping with each other, the recording and light transmitting layers are continuously adhered over at least two areas of the read only area and the recording and reproducing area, reflectivity of the recording layer is more than 5%, and a push-pull signal output T3 reproduced from the read only area and another push-pull signal output T4 reproduced from the recording and reproducing area before recording satisfies relations of T3?0.1, T4?0.1 and 1.5?T3/T4?0.5.

Abstract: An optical head includes a plurality of light receiving areas, which receive a first type of reflected rays where zero-order and first-order components of the light diffracted by a track are superposed one upon the other to generate a light quantity signal representing the quantity of light of the first type of reflected rays, and a non-light-receiving area, which is provided between the light receiving areas so as not to receive a second type of reflected ray consisting essentially of the zero-order components. As measured in a first direction in which the light receiving areas are arranged, a gap between the light receiving areas is longer than the width of the non-light-receiving area. The optical head further includes a tracking error signal generating section for generating a tracking error signal based on the light quantity signal.

Abstract: An apparatus for detecting the wobble carrier frequency of an optical disk is disclosed. The apparatus comprises an offset canceller, a binary conversion module, an adjustable band pass filter, and a frequency detection module. The offset canceller cancels the direct current offset of a first wobble signal to obtain a second wobble signal. The binary conversion module converts the second wobble signal to a binary data stream. The adjustable band pass filter passes only an adjustable frequency range of the binary data stream to generate a filtered signal, wherein the center frequency of the adjustable frequency range is sequentially adjusted. The frequency detection module then determines maximum amplitude of the filtered signal, and determines the center frequency of the adjustable frequency range according to which the filtered signal with the maximum amplitude is generated, wherein the wobble carrier frequency is the center frequency corresponding to the maximum amplitude.

Abstract: The invention provides an apparatus for demodulating an Address In Pre-groove (ADIP) symbol. The ADIP symbol is carried by a wobble signal of an optical disk and comprises a series of ADIP bits permuted according to one of a plurality of permutation patterns to make up the ADIP symbol. A wobble extraction module extracts the wobble signal from the optical disk. A reference wobble generator generates a reference wobble with the same frequency and phase as a fundamental frequency and phase of a positive wobble cycle of the wobble signal. A waveform difference measurement module then measures a difference between the wobble signal and the reference wobble to obtain a series of difference measurement values respectively corresponding to the ADIP bits. A pattern matching module then compares probabilities of the permutation of the ADIP bits agreeing with each of the permutation patterns according to the difference measurement values to determine the ADIP symbol.

Abstract: The invention provides a wobble detection circuit. An exemplary embodiment of the wobble detection circuit comprises an automatic gain control module, an analog to digital converter, a digital band pass filter, and a digital band pass filter. The automatic gain control module amplifies a first input signal and a second input signal detected by a pickup head to the same magnitude to obtain a first amplified signal and a second amplified signal. The adder then subtracts the second amplified signal from the first amplified signal to obtain an analog wobble signal. The analog to digital converter then converts the analog wobble signal to a first digital wobble signal. Finally, the digital band pass filter accepts frequency components of the first digital wobble signal within a pass band and rejects frequency components of the first digital wobble signal outside the pass band to obtain a second digital wobble signal.

Abstract: An information recording medium having at least a read only area and a recording and reproducing area is composed of at least: a substrate; a recording layer formed on the substrate so as to record and reproduce information; and a light transmission layer having transparency formed on the recording layer. The information recording medium is further characterized in that a wobbling groove corresponding to the read only area and another wobbling groove corresponding to the recording and reproducing area is formed on the substrate without overlapping with each other, the recording and light transmitting layers are continuously adhered over at least two areas of the read only area and the recording and reproducing area, reflectivity of the recording layer is more than 5%, and a push-pull signal output T3 reproduced from the read only area and another push-pull signal output T4 reproduced from the recording and reproducing area before recording satisfies relations of T3?0.1, T4?0.1 and 1.5?T3/T4?0.5.

Abstract: An information recording medium having at least a read only area and a recording and reproducing area is composed of at least: a substrate; a recording layer formed on the substrate so as to record and reproduce information; and a light transmission layer having transparency formed on the recording layer. The information recording medium is further characterized in that a wobbling groove corresponding to the read only area and another wobbling groove corresponding to the recording and reproducing area is formed on the substrate without overlapping with each other, the recording and light transmitting layers are continuously adhered over at least two areas of the read only area and the recording and reproducing area, reflectivity of the recording layer is more than 5%, and a push-pull signal output T3 reproduced from the read only area and another push-pull signal output T4 reproduced from the recording and reproducing area before recording satisfies relations of T3?0.1, T4?0.1 and 1.5?T3/T4?0.5.

Abstract: A recording and reproducing area and a reproduction-only area are formed by wobbling a groove formed in a spiral fashion to form a track to be tracked on a disk. The recording and reproducing area has address information recorded by wobbling of the groove and information recorded and reproduced by phase change marks on the track formed by the groove where the address information is recorded. The reproduction-only area has prerecorded information recorded by wobbling of the groove.

Abstract: A high-density read-only optical disc, and an optical disc apparatus and method using the same. The apparatus and method record data on a lead-in area of a high-density read-only optical disc such as a BD-ROM (Blu-ray disc ROM (Read Only Memory)) in the form of pre-pit strings associated with an HFM (High-Frequency Modulated) groove applied to a BD-RW (Blu-ray Disc Rewritable). Moreover, the apparatus and method continuously apply the same tracking servo operation to an entire area of the same high-density read-only optical disc or rewritable optical disc. Therefore, the apparatus and method can simplify an algorithm for controlling a plurality of tracking servo operations, and avoid an increased size of the optical disc apparatus.

Abstract: An information recording system for recording information on an optical disc using a reference clock signal generated based on a push-pull signal including a wobble frequency component, the system includes an amplitude obtaining unit for obtaining an amplitude value of the push-pull signal, a threshold calculation unit for calculating a displacement threshold of the push-pull signal based on the amplitude value obtained by the amplitude obtaining unit, and a noise reduction unit for generating a corrected push-pull signal by correcting the push-pull signal such that a displacement exceeding the displacement threshold is reduced. The reference clock signal is generated based on the corrected push-pull signal generated by the noise reduction unit.

Abstract: Second digital information serving as copyright protection information can be stably and reliably read without any effect of a defect or pit missing on a disk-shaped recording medium. Second digital information is recorded onto a disk-shaped recording medium by wobbling a pit sequence recorded as a first signal. The second digital information is recorded so that a plurality of bits constituting the second digital information are allocated in a unit period of an identical sync signal contained in the first signal. During playback, the plurality of bits constituting the recorded second digital information are read a plurality of times every unit period of the sync signal, and information of the read bits is then integrated. Thus, information from a large number of wobbled pits across unit periods of a plurality of sync signals can be integrated to determine the bit values.

Abstract: A recording medium, such as a high-density and/or read-only recording medium, such as BD-ROM, which includes copy protection information for preventing illegal copying of the contents recorded on the recording medium, and to methods and apparatuses for forming, recording, and reproducing data on the recording medium.

Abstract: Disclosed herein is a misjudgment correction circuit, including, an edge detection section configured to detect, in a binarized full addition signal obtained by adding first and second signals of the same or opposite polarity, edges at which the logic value of the binarized signal changes, a push-pull signal acquisition section configured to acquire a binarized push-pull signal obtained by subtracting the second signal from the first signal, a majority decision calculation section configured to acquire, in chronologic order, a plurality of logic values of the push-pull signal between the two adjacent edges so as to determine, by a majority decision, the more numerous of the two logic values, and a wave correction section configured to correct the push-pull signal between the edges to the more numerous logic value determined by the majority decision calculation section.

Abstract: An optical disc drive uses a tracking error signal derived from the wobble-induced signal components of the optical detector signal. This tracking error signal is relatively insensitive to beamlanding errors, and to differences in the signal amplitudes of the output signal of individual detector segments. Further, the need for a 3-spot grating is eliminated. A distinction is made between a situation where the track being followed is empty, and a situation where the track being followed is written. In case the track being followed is empty, a tracking error signal is derived from the wobble-induced signal components of the optical detector signal, whereas, in case the track being followed is written, a tracking error signal is derived from the data-induced signal components of the optical detector signal.

Abstract: An optical recording medium has a user data area and a lead-out area, wherein the user data area and the lead-out area each has grooves and lands formed thereon. Wobbles are formed on at least one lateral surface of grooves of the user data area and the lead-out area, and configured such that wobble characteristics are made different between the user data area and the lead-out area. Different types of wobbles are formed on the grooves of either the user data area or the lead-out area, thereby preventing an optical pickup that performs recording/reproduction from deviating from the user data area. Also, in a multi-layer optical recording medium, a whole area of a recording layer is configured to have a same condition, thereby preventing deterioration in reproduction and/or recording due to a difference in light power transmittance of another recording layer.

Abstract: An optical disc is manufactured under a uniform condition by forming grooves and lands on the entire surface of the disc. The optical disc is configured to obtain a reliable reproduction signal, and the grooves and lands are formed on a lead-in area, a user data area and a lead-out area of the optical disc. Since the same manufacturing condition can be adopted in mastering discs, the yield can be enhanced and the manufacturing cost can be reduced.