Abstract: A tracking control apparatus for stable tracking lead-in of an optical disc which has wobble grooves as tracks, including: a signal detection unit that detects tracking error and wobble signals from an optical spot; a speed detection unit that calculates a relative moving speed between the optical spot and the tracks; a polarity judgment unit that judges that the optical spot is on a land if a wobble signal amplitude value is equal to or lower than a predetermined value in the vicinity of a zero-cross point; a moving direction judgment unit that, when the relative moving speed is within a predetermined range and the optical spot is on a land, judges a moving direction of the optical spot from a rise/decay direction of the tracking error signal; and a control unit that performs a tracking lead-in by reducing the moving speed, based on the moving speed and moving direction.

Abstract: A radial tracking method for an optical information carrier format with non-uniformly spaced tracks is disclosed, wherein a plurality of tracks (21, 22, 23) are spaced apart at a track pitch TP2, respectively, within a broad spiral (20) having a track pitch TP, in an information layer of an optical information carrier. One central high intensity spot (25) and a plurality of symmetrically placed satellite spots (26, 27) are used for generating a tracking signal for said broad spiral (20). According to an embodiment, the push-pull signal is used for this purpose, resulting in a robust tracking signal. Further, unique address information is retrieved from each of the individual tracks within this broad spiral from a wobble of said tracks. As a result, higher storage densities are achieved, as the method enables tracking of narrowly spaced sub-tracks in a broad spiral that was previously not possible.

Abstract: The present invention relates to optical system capable of reproducing information from an optical carrier by a main beam (C) for reading information as readable effects on the carrier, and a first (A) and a second (B) auxiliary beam. The optical system is adapted to direct the main beam (C) and the first (A) and second (B) auxiliary beam onto the carrier so that the main beam is positioned on a first track, and the first and second auxiliary beam are oppositely positioned on a second and a third track. The optical system can adjust a push pull (PP) radial error signal from the main beam by a function; ƒ=ƒ(A, B, C), where the function ƒ is dependent upon adjacently positioned readable effects in the first, second and third track i.e. the local optical environment of the main beam. Therefore a filtering or “cleaning” of the push pull signal is performed depending on the local optical environment of the main beam.

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.

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: An optical disk device which drives an HD-DVD or the like. When recording or reproducing data with respect to an optical disk of HD-DVD, the address information is demodulated by an address decoding circuit and is supplied to a system controller. The system controller performs error checking using the CRC technique. When a resulting CRC value does not correspond to CRC bits, the system controller regards a bit in which the number of waves in wobbles having the same phase is not four, which is a predetermined value, as an error bit, and performs bit data replacement with respect to the error bit. Specifically, the system controller searches for a combination of bit values by which a resulting CRC value matches the CRC bits, thereby performing error correction.

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 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: 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: 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 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: For optical data storage applications a near field optical system can be used. In near field optical systems an accurate alignment of a solid immersion lens with respect to a disc surface is crucial. The correction of a tilt between the lens and the disc is performed by use of auxiliary beams. By comparing the gap signal for the auxiliary beams the air gap height and disc tilt can be determined.

Abstract: A method is provided to detect whether vertical deviation occurs as an optical disc spins in an optical disc player having a pickup head pre-installed in a balanced position at a focal distance. When moving towards and away from the balanced position, the pickup head generates a focus error signal with an S-curve. According to an input control signal, a focus actuator actuates the pickup head to keep it substantially at the focal distance. When the pickup head is not focused, the waveform of the input control signal is designed to actuate the pickup head back and forth within a predetermined range to generate the focus error signal with S-curves. Zero crossing points of S-curves are identified and input control values in the input control signal are obtained accordingly. The variation of the input control values is calculated, and whether vertical deviation occurs is determined by a predetermined procedure.

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: 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: Disclosed is an optical disc having angular information and a wobble track. A wobble signal generated according to the wobble track includes a phase corresponding to an angle of the optical disc. A detecting system for detecting the angular information of the optical disc is also disclosed, which includes a wobble signal detecting apparatus, a reference clock signal generating apparatus, and a phase comparator. The wobble signal detecting apparatus is used for detecting the wobble track on the optical disc to generate a wobble signal. The reference clock signal generating apparatus is used for generating a reference clock signal according to the wobble signal. The phase comparator is used for comparing the wobble signal and the reference clock signal to obtain the angular information of the optical disc. Alternatively, the wobble signal detecting apparatus can be used for detecting the wobble signal on the optical disc.

Abstract: An information storage medium according to an aspect of this invention has an information storage area for storing information, and a wobbled track which is used to guide a light beam on the information storage area, and is wobbled in correspondence with a frequency, a phase of which is modulated at predetermined timings to reflect predetermined information. The wobbled track is formed so that an evaluation result based on the frequency characteristics of a squared reproduction signal obtained by squaring a reproduction signal corresponding to the wobbled track, obtained from the reflected light of a light beam with which the wobbled track is irradiated, meets a predetermined evaluation measure.

Abstract: According to one embodiment, a wobble signal detection circuit comprises a phase control unit configured to read out a phase-modulated wobble signal from an optical disk and control a phase of the wobble signal to be coincide with a phase of a reference signal, a calculating unit configured to calculate a first correlation value showing an integration result between a phase controlled wobble signal which is controlled by the phase control unit and the reference signal, and a second correlation value showing an integration result between the phase controlled wobble signal and a phase-inverted signal of the reference signal, and a polarity determining unit configured to determine a polarity of the phase controlled wobble signal based on the first and the second correlation value.

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: 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: 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.

Abstract: An optical disc has a laminate of recording layers. The recording layers have tracks respectively. The tracks wobble in accordance with wobbling signals respectively, and thereby indicate the wobbling signals respectively. The wobbling signals result from modulation of bit streams formed by sequences of concatenated fixed-length words of a predetermined self-synchronizable code. Each of the words is composed of check point bits and information bits. The check point bits in each word represent a sync position and a layer identification information piece selected from different layer identification information pieces assigned to the recording layers respectively for indicating which of the recording layers the related word is assigned to. The information bits represent address information. A drive apparatus for a multi-layer optical disc, and a method of making a decision on a currently-accessed recording layer in a multi-layer optical disc are also disclosed.

Abstract: An adaptive frequency detector used in a phase locked loop for detecting a frequency difference between an input signal and an output clock generated from an oscillator of the phase locked loop includes: a frequency comparator for generating an up signal or a down signal according to the frequency difference between the input signal and the output clock; and a pulse controller coupled to the frequency comparator for generating a charge signal based on the up signal or generating a discharge signal based on the down signal. The pulse controller dynamically adjusts the pulse width of the charge signal or the pulse width of the discharge signal.

Abstract: The present invention provides an optical disc device and a method for focus control which enable an efficient operation for focusing without giving damages to an optical disc. A focus control section detects a focus position (drive voltage V1) by shifting an objective lens in the state where the optical disc is stopped (first step). Then, an amplitude (V2) of vertical deviation of the optical disc is detected from a reflected optical signal from the optical disc obtained by giving minute wobbling to the objective lens in the state where the optical disc rotates (second step). Based on the detected amplitude of vertical deviation of the optical disc, limit values (V3) are set for preventing collision between the objective lens and the optical disc. Then focusing is performed within a range defined by the limit values (third step).

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: 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: After pre-coding bit data of address information to be recorded on an optical disc on the basis of at least 4 wobble units, wobble data pre-coded on at least 4 wobble units is modulated by a BPSK (Binary Phase Shift Keying) or ASK (Amplitude Shift Keying) method, and the modulated wobble data is alternately recorded on both sides of a land and/or groove of the optical disc. As a result, wobble signals, recorded on sides of signal tracks of a groove and a land, in consecutively repeated anti-phase, or having consecutively repeated different amplitudes, are avoided. There are no consecutively repeated zero-level sections in a push-pull signal, thereby minimizing performance degradation of a wobble PLL (Phase-Locked Loop) and a noise generated in a reproduction RF signal.

Abstract: An optical pickup with a reflective coating device is provided, including a laser diode (LD), an optical element, and a photo detector integrated circuit (PDIC). The LD emits 1-3 lights with different wavelengths but the same polarization orientation. The beam transmits through the optical element set and focus on a recording media for data reading and writing. The beams are reflected by the recording media, through the optical element set, and detected by the PDIC for signal detection. The optical element set further includes a grating, a reflective coating device, and an objective lens. By using the reflective coating device to change the linear polarization orientation of the emitting light and the feedback light for 90° angle, the relative intensity noise caused by the feedback light in LD can be reduced.

Abstract: A recording medium type identification method and device is disclosed. The method and device of the present invention may easily identify the type of a DVD disk. The present invention is to remove pre-pit components, if any, from a wobble signal obtained from an optical disk to be identified, comparing a first peak-to-peak level of the wobble signal before the pre-pit removal process to a second peak-to-peak level of the wobble signal subjecting to the pre-pit removal process, and determining the optical disk type according to the comparison result. Alternatively, the present invention is to band-pass filter the wobble signal of the optical disk to be identified with a frequency range defined based on a center frequency of the wobble of a predetermined type of optical disk, driving a spindle motor with the processed wobble signal, and determining the type of the optical disk according to the rotation condition of the spindle motor.

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: A wobble signal reproducing device and method. The wobble signal reproducing device may include a computation unit for outputting a push-pull signal by use of a signal picked up by wobbling an optical disc; a wobble band pass filter (BPF) unit for applying band pass filtering to the push-pull signal based on a first control signal, applying low pass filtering to the band pass filtering-applied signal based on a second control signal, and outputting a wobble signal; a wobble phase locked loop (PLL) unit for generating a channel clock signal based on the wobble signal, wherein the first and second control signals correspond to the channel clock signal, the wobble BPF unit applies the band pass filtering at a center frequency varying based on the first control signal, and applies the low pass filtering at a cutoff frequency varying based on the second control signal.

Abstract: A method for generating a wobble clock signal. When the wobble signal becomes deformed or a defect on the optical disc is found, the present invention provides a stable wobble clock signal, which is used to maintain a stable rotation speed when the optical disc is processed. In addition, the present invention also determines whether the wobble signal is deformed according to the result of comparing the width of the wobble signal at different status with the average of the half cycle width of the wobble signal.

Abstract: In a demodulator for demodulating a BPSK modulated signal, demodulation performance degradation caused by analog circuits such as fabrication variation is suppressed, and furthermore, frequency variation in the BPSK modulated signal is followed by the demodulator. A multiplication circuit 105 multiplies a carrier, generated from a BPSK modulated signal by a carrier information extraction circuit 101 and a carrier generation circuit 102, by a digital BPSK modulated signal obtained by digitizing the BPSK modulated signal by an A/D converter 104 via a LPF 103. A carrier period integration circuit 106 integrates the multiplication result with respect to the period of the carrier, and the integration result is then binarized in a discriminator 107, thereby realizing demodulation.

Abstract: A wobble signal extraction circuit for extracting a wobble signal from a first optical disk signal containing a wobble signal component caused by a wobble formed on a surface of an optical disk and a second optical disk signal containing a wobble signal component of a reversed phase to that of the first optical disk signal, wherein signal level fixing sections (24a; and 24b) fix the first and second optical disk signals to a predetermined level when a discontinuity of the wobble is detected.

Abstract: A method for optical drive decoding of address in pre-groove (ADIP) data is provided to decode an input wobble signal to an ADIP unit signal. The method includes generating a wobble carrier frequency signal having the same phase with the wobble signal, multiplying the wobble carrier frequency signal by the input wobble signal to generate a product signal, accumulating the value of the product signal in each clock to generate a quotient summation signal, determining the phase change of the input wobble signal according to the value of the quotient summation to generate a phase change signal, and generating the ADIP unit signal by comparing the phase change signal with a plurality of ADIP patterns.

Abstract: A recording and/or reproducing apparatus and a method of controlling the same. The method of controlling the apparatus for recording information in or reproducing information from a disc having a wobbled track, the method includes detecting a wobble signal recorded in the wobbled track, and removing an error component occurring during the recording or the reproducing, based on the detected wobble signal. Accordingly, errors arising from a variety of factors can be accurately compensated for during a recording or reproducing operation.

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: A record carrier has a servo track indicating an information track intended for recording information blocks, which servo track has a variation of a physical parameter, referred to as wobble. The wobble is modulated for encoding record carrier information, such as addresses. The servo track is subdivided in non-modulated and parts modulated parts in which the frequency and/or phase of the variation deviates from the wobble frequency. The slope of the wobble is substantially continuous at transitions between the modulated and non-modulated parts by using wobbles starting at the maxima or minima of the wobble.

Abstract: The method of the present invention is capable of securely detecting LPP signals. The method comprises the steps of: reading a push-pull signal including a wobble component and LPP components; and slice-shaping the push-pull signal with a slice signal so as to binarize the LPP components and detect the LPP signals. The method is characterized by: detecting pulse widths of the LPP signals with changing voltage of the slice signal; calculating degree of dispersion of the pulse widths of the LPP signals; stopping the change of the voltage of the slice signal when the degree of dispersion exceeds a predetermined threshold value; and correcting the voltage of the slice signal on the basis of a predetermined correction value.

Abstract: A substrate for an optical recording medium includes recording tracks formed in guide grooves on a disc and an address section having an address pit sequence formed between the recording tracks in the guide grooves along an information reading direction of the recording tracks. The recording tracks in the guide grooves are divided into a prescribed number of zones. In each of the zones, the center of the address section corresponding to a recording track in the radially outermost or radially innermost guide groove is disposed so as to shift in a radial direction of the disc in relative relationship to the center of the recording track in the guide groove.

Abstract: A method and apparatus for recording information by irradiating light onto a medium to form a recorded domain, and method and apparatus for reproducing the recorded information are provided. In one example of the method, a plurality of light spots are modulated synchronously and irradiated onto a recording medium so that the plurality of light spots have an overlapped region on the recording medium. Since the profile of the total energy of the plurality of light spots is varied when the intensities of the plurality of light spots are modulated synchronously, it is possible to move the position where the total energy becomes maximum to any position on the optical recording medium. Thus, by moving the maximum point of the total energy of light spots in a cross-track direction, information can be recorded in a wobbled manner.

Abstract: A fine pattern having first elements within track widths and second elements, which are shifted half a track pitch from the first elements, are drawn across the entire surface of a disk accurately and at high speed. A transfer pattern for a magnetic transfer master carrier is drawn by scanning an electron beam on a disk coated with resist. The first elements and the second elements, which are shifted half a track pitch such that they straddle adjacent tracks, are drawn. While the disk is rotated unidirectionally, the electron beam is deflected in the radial direction within a single track of the disk to draw the first elements. Deflection of the electron beam in the radial direction is shifted half a track, to draw the second elements that straddle adjacent tracks at the same time.

Abstract: An information recording and reproducing apparatus performs information recording and reproducing on an optical disc having a recording track wobbled by a predetermined frequency. The apparatus includes an optical pickup which irradiates a laser light on the optical disc and receives the laser light reflected by the optical disc to output an electric signal corresponding to the laser light, a push-pull signal generating unit which includes a sample-hold unit and generates the sample-hold push-pull signal and the non-sample-hold push-pull signal from the electric signal, a sample-hold circuit which samples and holds the push-pull signal, a recording clock generating unit which generates a recording clock synchronized with the wobble signal based on the sample-hold push-pull signal during recording and based on the non-sample-hold push-pull signal during reproduction, and a phase adjusting unit which adjusts the phases of the non-sample-hold push-pull signal and the sample-hold push-pull signal.

Abstract: In this optical disk device, a reflected light of a light beam reflected from a pre-pit-formed side of a track wobbled on a disk is detected as a first detection signal. A reflected light of the light beam reflected from the other side of the track is detected as a second detection signal. The first detection signal and/or the second detection signal are/is amplified with a gain(s) so set that a peak value of a wobble signal component of the first detection signal coincides with a bottom value of a wobble signal component of the second detection signal.

Abstract: A method and apparatus for detecting information recorded as a phase-modulated wobble along a track of an optical disk, whereby a reference phase section is recorded with wobble having a predetermined reference phase and whereby respective polarities of phase integration values obtained by synchronous detection of phase-modulated unit sections following the reference phase section, in a playback wobble signal, are compared with the polarity of a reference phase integration value obtained for the reference phase section, to thereby detect respective bit states expressed by the phase-modulated unit sections.

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: User data recording areas and intermediate areas are alternately arranged on a disk. The intermediate area records at least information for synchronization.

Abstract: A recording medium having wobbled groove tracks out of phase with wobbled land tracks, a servo controlling apparatus using a wobble signal and a method thereof. The recording medium has land tracks and groove tracks, wherein both the land tracks and the groove tracks are wobbled, and wherein the wobbles of either individual groove tracks or individual land tracks are out of phase and the wobbles of the other type of individual tracks are in phase. Thus, it is possible to reliably address whether a groove (or land) track which is currently tracked by the pickup unit is a groove track or a land track, thereby ensuring addressing, and servo control can be effectively performed.

Abstract: A device for demodulating position information that is recorded as track wobbling in a record medium by a BPSK scheme includes a carrier-wave-generation circuit which derives a carrier wave from a wobbling signal obtained from the record medium, a phase-adjustment circuit which generates a phase-comparison signal having a 90° phase difference relative to the carrier wave, a multiplier which multiplies the wobbling signal and the phase-comparison signal to supply a product signal, and a detection circuit which detects a phase error of the carrier wave introduced by the carrier-wave-generation circuit by detecting the phase error between the wobbling signal and the phase-comparison signal based on the product signal.