Abstract: A disc driving apparatus and an information readout method according to the present invention realize optimum servo control of a readout unit in reading out the information from a recording medium having lands and grooves. The disc driving apparatus includes a unit for correcting tracking error signals, a unit for inverting signals corrected by the correcting unit to generate inverted tracking error signals, a unit for detecting which of the lands and the grooves the readout unit is scanning, and a unit for selecting the tracking error signals or the inverted tracking error signals according to the results of detection by the detection unit to tracking-control the readout unit by the selected signals.

Abstract: An optical disk apparatus includes: an optical pickup unit for reading out information recorded on an optical disk; a demodulation circuit for demodulating digital data from an output signal of the optical pickup unit; and a controller for performing a servo control based on the output signal of the optical pickup unit. When performing a focus/tracking control in a recess and a protrusion of a guide groove of the optical disk, the controller obtains a focus control gain difference between the recess and the protrusion by comparing focus offsets with respect to variations in amplitudes of signals from the optical disk for the recess and the protrusion, respectively.

Abstract: An information recording medium in which bottoms of a guide groove and a pit array formed on a disc substrate are allocated on a same flat plane and shaped in flat. Further, in a transition area from a pit array to a guide groove or from a guide groove to a pit array, the information recording medium is provided with an intermediate area composed of a pit array of which height changes from a height between a bottom and a side of a groove to another height between the bottom and a side of the pit array.

Abstract: An information recording medium in which bottoms of a guide groove and a pit array formed on a disc substrate are allocated on a same flat plane and shaped in flat. Further, in a transition area from a pit array to a guide groove or from a guide groove to a pit array, the information recording medium is provided with an intermediate area composed of a pit array of which height changes from a height between a bottom and a side of a groove to another height between the bottom and a side of the pit array.

Abstract: Even in an optical disk which includes, within a single disk, plural record areas whose track-pitches differ from each other, a tracking parameter is adjusted in a short time and with a high accuracy. At first, an optical pickup for reading information recorded in the optical disk is displaced into a reference track-pitch area which is one of the plural record areas of the optical disk. Moreover, the tracking gain is adjusted so that the tracking servo gain in this area may exhibit a predetermined characteristic. Also, the value thus acquired is recorded into, e.g., a non-volatile memory. After that, based on the tracking parameter learned/adjusted in the reference track-pitch area, the tracking parameter in another track-pitch area is calculated using the track-pitch ratio therebetween. Thereby it becomes possible to adjust the tracking parameter in a short time and with a high accuracy.

Abstract: An information recording medium in which bottoms of a guide groove and a pit array formed on a disc substrate are allocated on a same flat plane and shaped in flat. Further, in a transition area from a pit array to a guide groove or from a guide groove to a pit array, the information recording medium is provided with an intermediate area composed of a pit array of which height changes from a height between a bottom and a side of a groove to another height between the bottom and a side of the pit array.

Abstract: An optical disc drive according to the present invention reads and/or writes data from/on an optical disc having at least one information layer with a light beam and includes: a spherical aberration detecting section for generating a spherical aberration signal representing a spherical aberration produced at a focal point of the light beam on the information layer of the disc; a spherical aberration changing section for changing the spherical aberration; a spherical aberration regulating section for generating an aberration correction signal to correct the spherical aberration by driving the changing section; and means for detecting a value of the aberration correction signal that minimizes the spherical aberration when the focal point of the light beam is located on the information layer of the disc and for detecting the depth of the information layer, which corresponds to a distance from the information layer on which the focal point of the light beam is located to the surface of the disc, based on the valu

Abstract: The invention provides a servo calibration mark detection circuit for use in an optical disk drive. In one embodiment, the servo calibration mark detection circuit comprises a summing processor, a slicing level generator, and a comparator. The summing processor sums an intensity of a light beam reflected from both an inner groove and an outer groove to obtain a first signal. The slicing level generator generates a slicing level. The comparator then compares the first signal with the slicing level to obtain a second signal, wherein the second signal indicates a first location of a first servo calibration mark recorded on the inner groove and a second location of a second servo calibration mark recorded on the outer groove.

Abstract: A recording disc and recorded information reproducing apparatus and method for immediately starting reproduction of information when a push-pull based tracking control is employed to reproduce recorded information from the recording disc. The recording disc comprises an information data area for recording recording marks which carry information data in columns, and a control data area for recording identification information indicative of a recording pattern of the recording marks in the information data area.

Abstract: An optical disc recording and reproducing apparatus for recording and reproducing data in and from an optical disc by the use of the optical disc as a recording medium, comprises analog processing means including a binarization unit for subjecting a signal read from the optical disc to binarization and a servo unit for controlling recording and reproducing a signal in and from the optical disc; synchronous clock generating means for generating a synchronous clock signal which is synchronized with the signal read from the optical disc; address detecting means for detecting address information indicating a physical position on the optical disc based on the signal read from the optical disc, and outputting a signal indicating the address information and a signal indicating that the address has been detected when the address information has been detected; a sector counter for holding a sector count value of a sector as a recording unit on the optical disc, and updating the sector count value according to the sync

Abstract: A recording disc and recorded information reproducing apparatus and method for immediately starting reproduction of information when a push-pull based tracking control is employed to reproduce recorded information from the recording disc. The recording disc comprises an information data area for recording recording marks which carry information data in columns, and a control data area for recording identification information indicative of a recording pattern of the recording marks in the information data area.

Abstract: An optical-information recording medium includes a substrate that includes a servo surface having a servo pattern thereon; an information recording layer laminated on the servo surface of the substrate capable of recording information as a hologram produced by interference between an information beam containing the information and a reference beam; an address servo area that is formed as a part of the servo pattern, and that records therein address information and clock information for aligning a beam, emitted from an optical-information recording apparatus for recording information in the information recording layer, to a target position in the information recording layer; and a following up servo area that is formed as a part of the servo pattern, and that is to be irradiated by the beam to make the beam follow a rotation of the optical-information recording medium.

Abstract: An optical disk unit of this invention includes a defocus detecting system for detecting a defocus of an objective lens, a thickness unevenness detecting system for detecting a thickness unevenness of a transparent resin layer provided nearest the objective lens of a recording medium, and a thickness unevenness correcting mechanism for changing the focusing characteristic of light impinging upon the objective lens based on a change in the thickness of the transparent resin layer detected by the thickness detecting system.

Abstract: An optical disk unit of this invention includes a defocus detecting system for detecting a defocus of an objective lens, a thickness unevenness detecting system for detecting a thickness unevenness of a transparent resin layer provided nearest the objective lens of a recording medium, and a thickness unevenness correcting mechanism for changing the focusing characteristic of light impinging upon the objective lens based on a change in the thickness of the transparent resin layer detected by the thickness detecting system.

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 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 information storage medium includes a lead-in area, a lead-out area, and a user data area between the lead-in and lead-out areas and in which user data is recorded. Pits are formed in the lead-in area, the user data area, and the lead-out area, and a track pitch in all or a portion of the lead-in area is different from a track pitch in the remaining area of the optical information storage medium.

Abstract: The present invention provides a focus position adjustment method for adjusting a focus position by which an optical storage device reads an optical storage medium. The optical storage medium comprises a header and a recording area. The optical storage device generates a focus error signal as reading the medium and utilizes the focus error signal to control the focus of the optical pickup head. After the optical storage device finishes tracking closed loop, the method is performed according to the deviation value between the levels of focus error signals of the header and the recording area to adjust the focus position to make the deviation value fall in a predetermined range. The system comprises a deviation value detection module for determining the deviation value and a focus control module for adjusting the focus position.

Abstract: An optical disk unit of this invention includes a defocus detecting system for detecting a defocus of an objective lens, a thickness unevenness detecting system for detecting a thickness unevenness of a transparent resin layer provided nearest the objective lens of a recording medium, and a thickness unevenness correcting mechanism for changing the focusing characteristic of light impinging upon the objective lens based on a change in the thickness of the transparent resin layer detected by the thickness detecting system.

Abstract: A tracking control apparatus comprises an signal processing section, a lens characteristic measuring section and an optimum lens position searching section. The lens characteristic measuring section acquires a first address and second address of an optical disk. The lens characteristic measuring section successively generates offset set values so that the position of a converging lens is moved by an actuator at predetermined spatial intervals and counts the number of times both the first address and the second address are acquired. The optimum lens position searching section searches for a maximum value of the acquisition count and moves the converging lens using the actuator based on the offset set value when the acquisition count reaches a maximum value.

Abstract: A method of identifying a type of a disc includes steps of: obtaining a first address of a first position on the disc; moving a pick-up unit to a second position of the disc; obtaining a second address of the second position; calculating a difference between the first address and the second address; and identifying the type of the disc by comparing the difference with a predetermined value.

Abstract: A land/groove track discriminating method and apparatus for an optical recording medium having a land/groove structure which can stably discriminate the kind of a track even in an unstable state of the system. The kind of the track is discriminated by using the differential characteristic of a tracking error signal in a header region, by using the relation that the phase of a wobbling signal in the lang track is opposite to the phase of the wobbling signal in the groove track, or by comparing phase levels of delayed first and second header region signals. Accordingly, the servo control suitable to the kind of the track can be performed at a proper time, and thus an accurate tracking control can be performed with respect to an optical disc having the land/groove track structure.

Abstract: An optical disc recording apparatus can draw an image by radially vibrating a laser beam under stable focus control. A pickup radiates the laser beam onto the optical disc rotated by a spindle motor. A focus servo controller maintains a constant spot diameter of the laser beam on the optical disc by detecting a return light of the laser beam reflected back from the optical disc. An irradiation position controller operates when the pickup opposes a label face of the optical disc for controlling an irradiation trajectory of the laser beam to vibrate in a radial direction of the optical disc while the laser beam runs along circumferential zones defined on a coloring layer of the label face. A modulating section modulates an intensity of the laser beam for forming dots along the circumferential zones so as to draw the image.

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 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 moved distance detecting means (15) detects the moved distance in a tracking direction of an object lens, a position signal generating means (60) generates a position signal corresponding to the position of the object lens based on the detection, and a drive signal modulating means (40) modulates the drive current of a magnetic head (20) according to this position signal. Therefore, a drive current can be controlled according to the moved distance of the object lens to enable the magnetic head to be driven with a small current when a moved distance is small and with a large current according to a moved distance only when it is large, whereby it is possible to reduce an average drive current and hence reduce power consumption as a whole.

Abstract: An optical head device includes a light source for emitting light; a collection optical system for collecting the light emitted by the light source to an information memory medium including tracks having prescribed grooves; a light detector having a plurality of detection areas for receiving the light reflected by the information memory medium and outputting a signal in accordance with a light amount of the light received; a tracking error signal generator for receiving the signals output from the light detector and generating a tracking error signal based on the signals; and a light division element for dividing a reflected light reflected by the information memory medium.

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: In a land pre-pit address demodulating device DM for detecting land pre-pit address information during recording to a DVD-R/RW-disc, a tracking error signal TE is muted by a first reference potential Vref1 during a period in which the tracking error signal TE is generated from a reflected laser beam having a power for recording a mark, an RF residual component is removed from the tracking error signal TE, and the tracking error signal TE from which the RF residual component has been removed is compared with a second reference potential Vref2, thereby detecting a land pre-pit address signal.

Abstract: An adaptive focusing apparatus and method thereof of an optical disc drive having a focus servo controller moves a pickup head to an optimal focus point. A disc driver rotates an optical disc and includes a reflected signal detector detecting a signal reflected from the optical disc by the pickup head and a signal processor preventing spikes between a surface of the optical disc and the pickup head in response to the reflected signal and generating a focus drive signal for the focus servo controller using an adaptive focus search algorithm. The algorithm includes a static part and a dynamic part to reduce a focus search time. Accordingly, damage to the optical disc due to spikes between the surface of the optical disc and the pickup head can be prevented and a focus search time can be reduced.

Abstract: An apparatus for holding digital data. The apparatus includes a medium in which a plurality of dimples are spaced for tracking by a playing apparatus. Each dimple includes a plurality of facets, and each facet represents a data bit. Because the location of each dimple is predetermined, a tracking assembly can use the dimple locations for tracking purposes. Thus there is no need to reserve bits for tracking purposes, and more data can be stored in a given space on a given medium than with previously developed high-density digital storage media.

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 disk device in which data is written to or reproduced from an optical disk having an area which contains a header section and another area which does not contain a header section. When a track deviation of an optical pickup occurs, it is detected whether or not a signal representing the header section is contained in the return light signal from the optical disk. When a signal representing the header section is contained in the return light signal, it is determined that the optical pickup is located in an area which contains a header section and tracking is controlled through a push-pull method etc. On the other hand, when a signal representing the header section is not contained in the return light signal from the optical pickup, it is determined that the optical pickup is located in an area which does not contain a header section and tracking is controlled through differential phase detection etc.

Abstract: A surface treatment of a light transmissive layer by spin coating is carried out in a simple way at low cost. When a light transmissive layer is to be formed by spin coating, the transfer of an information recording layer is carried out using a resin stamper having a convex portion in an outer peripheral portion. At the same time, an inclined plane (concave portion) is formed on the side of a substrate (member on which transfer is performed). As a result, coating is achieved in such a manner that a raise in the outer peripheral portion is prevented from being noticeable.

Abstract: An optical reproducing apparatus for reproducing information on a medium includes a light source, an optical system for irradiating a light beam generated by the light source on the medium, a detector for detecting a reflected light from the medium; and a reproducer means for reproducing information on the medium by using a signal from the detector. The medium is a substrate having grooves and lands alternately formed thereon in a radial direction, which serve as recording tracks and have prepits.

Abstract: Method of recording control signals on a removable optically readable disc like recording device comprising recording control data representing the physical structure of an optically readable disc. The control data set either being a standardized set of control data corresponding to the record carrier or either being a non-standardized set of control data deviating form the standardized set of control data signals. Preferably the non-standardized set of control data relates to different values for the number of information layers present on the record carrier or the type of record carrier being of the read-only type, recordable or rewritable type. Preferably a user may select the non-standardized set of control data by selecting a corresponding type of playback and/or recording apparatus.

Abstract: A high density optical information recording medium comprises a substrate having rows of land and groove and a recording layer formed on the substrate. Each of the rows of land or groove includes at least two recording tracks separated by a denatured region produced by irradiating e.g. the center of each row in the recording layer with a denaturing light beam accompanied with one or two sub-beams for tracking control. Recording and reproduction of information can be performed likewise by using a recording or reproduction light beam accompanied with one or two tracking sub-beams.

Abstract: An optical disk unit of this invention includes a defocus detecting system for detecting a defocus of an objective lens, a thickness unevenness detecting system for detecting a thickness unevenness of a transparent resin layer provided nearest the objective lens of a recording medium, and a thickness unevenness correcting mechanism for changing the focusing characteristic of light impinging upon the objective lens based on a change in the thickness of the transparent resin layer detected by the thickness detecting system.

Abstract: The present invention provides an information storage apparatus that generates a tracking error signal based on a detection signal, and performs various control operations based on the tracking error signal. When the operation mode is a seek operation mode, the information storage apparatus generates a tracking error signal by holding the peak value of the detection signal. When the operation mode is a tracking operation mode, the information storage apparatus generates a tracking error signal directly from the detection signal. With this information storage apparatus, stable control operations can be performed, regardless of changes of conditions.

Abstract: The focus is moved from a first layer (L0) to a second layer (L1) of a double-layered optical disk by stopping a control loop operation and applying acceleration pulses for an interlayer jump to a two-axis electromagnetic actuator. Here, switching timing between acceleration and deceleration for an interlayer jump is generated based on the rate of change of a SUM signal obtained from a light-sensitive element (27), the SUM signal is distinguished by a specific threshold TH, and an S-shaped error signal is distinguished by thresholds THH and THL with different positive/negative level, thereby performing a pull-in operation of focus control. In addition, at the time of the interlayer jump, a liquid crystal element (23) for correcting the spherical aberration is optimized in advance for the cover layer thickness of the target layer L1.

Abstract: A light beam from a light source is introduced to a grating element of a pickup device to create zero order diffracted light, ±first order diffracted light, and ±second order diffracted light. An irradiation system focuses the zero order, ±first order and ±second order diffracted light onto tracks extending on a recording surface of an optical recording medium to form spots. A spot of the zero order diffracted light is formed on a target track, spots of the ±second order diffracted light are formed on tracks adjacent to the target track, and spots of the ±first order diffracted light are formed midway between the spots of the ±zero order and ±second order diffracted light. An optical system guides returning light reflected from the spots to an optical detector. The optical detector has independent light-receiving elements for receiving the returning light. A servo signal calculator creates an error signal based on the output signals from the optical detector.

Abstract: On an optical disk, a string of a plurality of pits having two different depths is formed. Quantity of light reflected from the pit string is detected by a photoreceptor element, and based on the detected quantity of reflected light, a pit depth detecting unit detects depth of each pit. Based on the detected quantity of reflected light, a servo signal generating unit generates a tracking servo signal. An output control unit supplies the generated tracking servo signal when a pit of such depth that is to be reproduced is tracked, and holds and supplies an immediately preceding tracking servo signal when a pit of different depth is being tracked, based on the result of detection by the pit depth detecting unit.

Abstract: A DVD recognition method and apparatus is disclosed. First, a disc recognition apparatus uses a laser with a specific wavelength to irradiate an inner area of the DVD, thereby obtaining an inner TE signal. Then, the disc recognition apparatus uses the laser to irradiate an outer area of the DVD, thereby obtaining an outer TE signal. Afterward, the type of the DVD is recognized according to the inner and outer TE signals.

Abstract: An apparatus for reading and/or writing data markings of an optical recording medium having data markings arranged along a track and header markings arranged laterally offset with respect to the center of the track, the apparatus having a header identification unit. According to the present invention an intermediate track signal is formed, which enables direction identification during the traversal of tracks. The present invention comprises an apparatus having a header sequence detector, a track crossing detector and an intermediate track detector, wherein the intermediate track detector is connected to outputs of the header identification unit, the track crossing detector and the header sequence detector, and generates an intermediate track signal.

Abstract: An optical information recording and reproducing apparatus for recording and reproducing an information signal on/from both concave portions and convex portions of guide grooves formed on a recording medium is disclosed.

Abstract: On an optical disc including a substrate on which pits having at least two different depths are formed, main information is recorded by the shape of the pits and additional information is recorded by the depth of the pit. It is possible to reverse polarity of a tangential push-pull signal dependent on the depth of the pit, and therefore it becomes possible to record information utilizing the depth of the pit. This improves recording density of the optical disc. Further, when information of the optical disc is to be copied, the information recorded by the depth of the pit cannot be copied. Therefore, unauthorized reproduction can be prevented.

Abstract: An information recording medium comprises a read-out track having a data region forming data bits for reproduced data and a servo pattern region forming servo bits for tracking control. The servo bits have a first groove that is deep in a direction perpendicular to both a length of the read-out track and a depth of the information recording medium, and a second groove that is deep in a direction opposite to the first groove and having a depth gradually increasing along the read-out track.

Abstract: The present invention is a method and system to provide focus control in a multi-layer optical storage medium. The method comprises generating a beam of light and reflecting the beam of light off one of a first and a second optical layers on a disk. The reflected beam is detected and a servo signal is provided in response to the reflected beam. The light source is directed to move from a first position to a second position based on the servo signal, so as to focus the light source from one of the first or the second optical layer to another one of the first or the second optical layer.

Abstract: To provide an optical recording medium and an eccentricity amount detecting device using the same that can detect an eccentricity amount representing a relative displacement amount in a radiation direction between a beam spot irradiated onto the optical recording medium and the optical recording medium. In the optical recording medium, a plurality (N) of servo areas (113) each including a first wobble mark (211) and a second wobble mark (212) and a plurality (N) of data areas for performing information recording and reproduction are arranged alternatively in a circumferential direction. Each of the servo areas is composed of a plurality of servo pattern areas (210a to 210c) arranged in the radial direction, which vary in a distance in the circumferential direction between the first wobble mark and the second wobble mark. The plurality of servo pattern areas include the same number of tracks, and the number is less than N/(2×?).

Abstract: In a method and an apparatus for aberration correction according to the invention, aberration occurring in recording/reproducing information derived from causes such as thickness variation of a substrate, a tilt, a focus error and a tracking error is detected, and the aberration is corrected by correcting these causes.

Abstract: Audio data of 20 bits is separated into first data of upper 16 bits and second data of lower 4 bits. EFM modulation data is formed from the first data. A laser beam is on/off controlled in correspondence to the logic level of channel data obtained by NRZI modulating a serial data train. The first data, therefore, is recorded in a manner similar to the case of a compact disc. Each pit is controlled so as to have a displacement in the right/left direction for the track center in accordance with the second data and the deviated pit is formed. When data is recorded by the displacement of the pit, since a high frequency component of a tracking error signal changes upon reproduction, the second data can be extracted from the tracking error signal.

Abstract: A power control device for controlling a power of a light source of an optical beam directed to an optical medium. The power control device includes a reflected light detector for detecting reflected light from the optical medium when irradiated by an optical beam which is following a track; an arithmetic unit for calculating from the reflected light a transmissivity of light transmitted from a disk surface to a recording layer or an amount of directed light on the recording layer of the medium; and power control means for controlling the power of the light source for emission based on a calculation result produced by the arithmetic unit.