Abstract: An information recording medium having a spiral or concentric-shaped groove structure along a track formed on a disk-like substrate. The medium has the groove structure wobbled in a radius direction of the medium and the track is divided into a plurality of recording units in the track direction by at least one radial boundary line. At least two adjacent recording units in the radius direction of the medium comprise one zone, and the groove structure included in the respective recording units within one zone has at least one of substantially the same number of wobbling and the wobbling cycle.

Abstract: An optical disc apparatus being able to read and write from and into an optical disc of a wobble groove type or method, a rotation control of a spindle motor is performed including a spindle controller portion and a PWM oscillator generating a clock for use of rotation control, wherein the frequency of the clock for use of rotation control is set to be different from that of a wobble signal or outside an area ±50% of wide capture fluctuation of the wobble signal, thereby providing the optical disc apparatus with which external disturbance on the wobble signal or the like can be reduced and a stabilization of the optical disc apparatus can be obtained.

Abstract: An optical disc apparatus and method for recording and reproducing information to/from an optical disc, including discrimination of the optical disc, reading control information in an un-recordable area formed in an inner periphery of the optical disc, conducting focus control based on a focus error signal in a recordable area formed outside of the un-recordable area, and determining an optimum offset value of the focus error signal in the recordable area. Further, adjustment in amplitude of a reproduced signal from an inner periphery of the recordable area is conducted, test-writing in the inner periphery of the recordable area is conducted, test-writing in an outer periphery of the recordable area is conducted, and adjustment in amplitude of a reproduced signal from the outer periphery of the recordable area is conducted. The respective operations are conducted sequentially so as to make the optical disc in a reproducible and recordable condition.

Abstract: An optical disc apparatus having at least two optical condenser lens for recording and reproducing information of an optical disc, comprising: means for discriminating the optical disc; means for reading control information in a ROM area which is formed in an inner periphery of said optical disc; means for conducting focus control in a RAM area which is formed outside of said ROM area; means for conducting adjustment in amplitude of a reproduced signal from an inner periphery of said RAM area; means for conducting a pre-writing (a sample-writing); means for conducting test-writing in the inner periphery of said RAM area; means for conducting test-writing in an outer periphery of said RAM area; and means for conducting adjustment in amplitude of a reproduced signal from the outer periphery of said RAM area, wherein said means conducts the respective operations sequentially, thereby making said optical disc in reproducible and recorable condition, with a short time period and with a smooth confirmation operatio

Abstract: A beam is irradiated to an information recording medium having land tracks and groove tracks alternately formed on a track formed in turn on an information recording surface thereof and pre-pits so pre-formatted as to deviate from the center of the track, a return beam of the irradiated beam is received by detectors split into two parts in a track direction to obtain a differential signal, the pre-pit is detected from this differential signal and control of recording and reproducing processings is executed by using the pre-pit detection signal so obtained as the reference.

Abstract: An information recording medium having spiral or concentric-shaped groove structure along a track formed on a disk-like substrate. The medium has the groove structure wobbled in a radius direction of the medium and the track is divided into a plurality of recording units in the track direction by at least one radial boundary. At least two adjacent recording units in the track direction of the medium comprise one zone and the medium includes a plurality of the zones. The groove structure included in the adjacent recording units within any zone has substantially the same number of wobbling.

Abstract: An information recording medium having a spiral or concentric-shaped groove structure along a track formed on a disk-like substrate. The medium has the groove structure wobbled in a radius direction of the medium and the track is divided into a plurality of recording units in the track direction by at least one radial boundary line. At least two adjacent recording units in the radius direction of the medium comprise one zone, and the groove structure included in the respective recording units within one zone has at least one of substantially the same number of wobbling and the wobbling cycle.

Abstract: An information recording medium having spiral or concentric tracks with a plurality of grooves and lands formed on a disk-like substrate. Each of the tracks is divided into a plurality of recording units and each of the recording units includes a blank portion in a circumferential direction of the track. The track is formed with a wobble in a radial direction and each of the recording units has a length which is an integer multiple of a cycle of the wobble.

Abstract: A beam is irradiated to an information recording medium having land tracks and groove tracks alternately formed on a track formed in turn on an information recording surface thereof and pre-pits so pre-formatted as to deviate from the center of the track, a return beam of the irradiated beam is received by detectors split into two parts in a track direction to obtain a differential signal, the pre-pit is detected from this differential signal and control of recording and reproducing processings is executed by using the pre-pit detection signal so obtained as the reference.

Abstract: For a disk of a land/groove scheme with land tracks and grooves appearing alternately, in order to enable stable and reliable reproduction of information as recorded on a disk by stably and reliably detecting a specific position at which a land track and groove change therebetween, a technique is employed for detecting the position whereat one land track is changed to a groove, or vice versa, by utilizing an HPP signal rather than an RF signal in cases where an optical head 103 attempts to reproduce certain information at the pit formation position of a disk 101. In addition, detect the polarity--positive or negative--of a pit signal appearing in the HPP signal, and then detect the position whereat the land track and groove change therebetween based on the position at which the order or sequence thereof changes, thereby permitting effectuation of optical head's tracking control and focus control by a method suitable for its respective parts.

Abstract: In a wobble signal detecting circuit provided by the present invention, a wobble signal is converted into binary data before being supplied to a PLL circuit by way of a polarity switching circuit and a clock switching circuit. The PLL circuit outputs a recording/playback timing generation clock signal. The frequency of the recording/playback timing generation clock signal is divided by a frequency dividing circuit before being fed back to the PLL circuit. A difference in phase between the wobble signal and the feedback signal is detected by a phase inversion detecting circuit and, if the difference in phase exceeds a phase difference determined in advance, the phase inversion detecting circuit generates a polarity switching signal for switching the polarity of the wobble signal. The polarity switching signal is used to invert the polarity of the polarity switching circuit.

Abstract: A disk-like information recording medium includes recording areas provided in both of a groove portion and a land portion. The information recording medium is divided into groups of a plurality of areas, each track is divided into circular arc-shaped sectors having the same central angle arranged to be radial in the radius direction, identification information is provided at every sector, each track is divided into groups in such a manner that lengths of the circular arc-shaped sectors become almost constant among the groups, and the groove portion and the land portion are wobbled in the radius direction of the information recording medium. When the groove portion information track and the land portion information track which are the recording portions are wobbled in the radius direction, position information can be reliably obtained from the recording portions, and hence recorded information can be accessed reliably.

Abstract: A disk-like information recording medium includes recording areas provided in both of a groove portion and a land portion. The information recording medium is divided into groups of a plurality of areas, each track is divided into circular arc-shaped sectors having the same central angle arranged to be radial in the radius direction, identification information is provided at every sector, each track is divided into groups in such a manner that lengths of the circular arc-shaped sectors become almost constant among the groups, and the groove portion and the land portion are wobbled in the radius direction of the information recording medium. When the groove portion information track and the land portion information track which are the recording portions are wobbled in the radius direction, position information can be reliably obtained from the recording portions, and hence recorded information can be accessed reliably.

Abstract: An optical disk device which improves the S/N ratio of reproduced signals and increases the recording density on it. Pulsed reproducing light is projected onto the data detection points on the optical disk medium to reproduce the data. This enables the reproduction of signals of large optical intensity without raising the temperature of the recording layer. A servo region is irradiated with DC light to form channel clocks from the PLL.

Abstract: A spatially-independent N amorphous point train is formed by pulse width modulation of a laser to record information in a sample-servo optical disk drive used for a personal computer. Amorphous points are each formed by a pair of a high-power recording pulse WH and a lower power recording pulse WL for rewrite, conducted together with erasing of previous information by pairs of a high-power erasing pulse EH and a lower power erasing pulse EL with power relationships enabling integration of power per pulse of WH and WL with respect to time to substantially equal integration of power of EH and EL with respect to time, and control of recording pulse power such that a high-power level WH1 for all but a leading amorphous point is greater than a high-power level WH2 of the leading amorphous point, so that a low power level WL1 of all but a trailing amorphous point is less than a low power level WL2 of the trailing amorphous point.

Abstract: An optical disk apparatus includes a recording method in which at least one of the scanning position, the irradiation time, the irradiation start point and the irradiation power of a light beam is arbitrarily changed, and a method and apparatus in which information is represented by a plurality of recording marks without being limited to two kinds of recording and erasion. In order to prevent overlapping recording/erasion, a recording clock generating unit delays a reference clock signal to generate a recording clock signal and a recording control unit transfers user data to an optical head in synchronism with the recording clock signal so that it is recorded on an optical disk. Also, the amount of delay is recorded to enable sure reading or reproduction. At the time of reading, a servo mark detection signal is divided to generate a clock signal having a variable frequency, thereby realizing an optical disk for which high-precision recording/reproduction is possible.

Abstract: A data recording/reproduction method and apparatus uses an optical disk equipped with wobbling track guide grooves disposed in a track scanning direction and minutely wobbled. The apparatus uses a circuit for detecting and correcting displacement of an optical spot position from the wobbling track, and a system for allowing data to correspond to front and rear edges of recording pits as a recording system, and includes a circuit for independently handling reproduction pulses obtained from reproduction signals of the recording pits on the front and rear edge sides and for generating reproduction clocks. A circuit resynthesizes the two series of reproduction pulse trains by a specific pattern portion in the data. Another optical disk apparatus divides each track into zones, and switches a rate of revolution each zone to attain a substantially equal linear velocity. A servo signal reproduction clock generation circuit and a data signal recording/reproduction clock generation circuit are disposed separately.