Abstract: A crosstalk amount of a rewritable optical disk at an optimum recording power is stored, then the data recorded on the rewritable optical disk are reproduced upon overwriting the data on the rewritable optical disk, then a crosstalk amount in a reproduced signal is detected, and then this crosstalk amount is compared with a reference crosstalk amount. Since the crosstalk amount has such a characteristic that such crosstalk amount is increased larger as a width of a pit is thickened, i.e., a recording power is increased higher, it is possible to detect a recording power value by comparing the crosstalk amounts. As a result, the crosstalk amounts of both data are compared with each other by utilizing this characteristic, and then the recording conditions such as an erasing power, the recording power, etc. are changed in response to the compared result to overwrite the data.

Abstract: An optical disk recording apparatus operates on an optical disk having circular tracks which are provisionally written with an index signal used for securing a constant linear velocity of the optical disk from an innermost circular track to an outermost circular track, and records data along the circular tracks at different linear densities on different annular zones of the optical disk. In the apparatus, a disk drive section rotates the optical disk while synchronizing the index signal successively read from the rotated optical disk with a predetermined reference clock signal to thereby maintain the constant linear velocity of the circular tracks. A clock generating section multiples or divides the reference clock signal by different rates to generate different writing clock signals in correspondence to the different annular zones of the optical disk.

Abstract: An optical recording method is designed for recording data on a recordable optical disk by use of a laser beam of a present recording apparatus under a desired recording condition. The method detects identification information which is reserved in the optical disk and which is indicative of a type of a previous recording apparatus. The detected identification information is compared with a plurality of identification information which are previously stored in correspondence to various types of recording apparatuses. As results of the comparison, the method determines whether the detected identification information matches with one of the stored identification information which does not correspond to the type of the present recording apparatus. Upon the determining of matching, the method retrieves a recording condition which is previously stored in association with the matching identification information.

Abstract: An optical disk recording apparatus is designed for forming pits on a recording surface of an optical disk of a given type at a given recording speed by applying a laser light in the form of a sequence of multiple pulses obtained by intermittently turning on and off the laser light according to a given multi-pulse pattern. In the apparatus, a write strategy circuit is set with a pattern table and controls the turning on and off of the laser light according to a multi-pulse pattern selected from the pattern table in correspondence to a length of the pit to be formed. A storage section stores a plurality of pattern tables of different kinds, each pattern table containing a plurality of multi-pulse patterns corresponding to a plurality of lengths of the pit. A control section selects one of the pattern tables based on either of the recording speed and the type of the optical disk, and reads out the selected pattern table from the storage section and sets the read pattern table in the write strategy circuit.

Abstract: Information indicative of disk-applicable recording speeds is incorporated in lead-out start time information within ATIP information that is recorded in pre-grooves located in a lead-in area of an optical disk. Once the optical disk is inserted in an optical disk recording device, the lead-out start time information is read out, so that recording is performed on the optical disk after a recording speed is automatically set to a highest settable speed value within a range specified by the read-out lead-out start time information. This arrangement can reliably prevent recording at speeds beyond predetermined limit values unique to the optical disk.

Abstract: In an optical recording apparatus having an optical pickup, a rotating section is provided for rotating an optical disk which is formed thereon with a guide groove to define a spiral track having a plurality of rounds. The optical pickup has a light source for generating an optical beam and a diffractive grating for diffracting the optical beam to form a main beam and a pair of sub beams opposite with each other relative to the main beam. The optical pickup is operable for irradiating the main beam to the spiral track with accompanying the pair of the sub beams along apposite sides of the spiral track. A servo section operates the optical pickup to enable the main beam to trace the spiral track based on a tracking error signal derived from return lights of the sub beams reflected back from the optical disk. A recording section modulates the main beam for recording of information onto the spiral track while the optical dick is rotated.

Abstract: An optical disk includes a standard area of a standard recording density provided on an inner peripheral sided and a high density area of a higher recording density provided on an outer peripheral side. In each of the standard area and the high density area, a program area is provided so that an independent program can be recorded in each program area. In one aspect of the invention, an optical disk includes, from the inner preriphery to the outer periphery of the disk, a ROM area for read-only purpsoe, a RAM area in which information can be rewritten and a WO area in which information can be written only once.

Abstract: An optical disk has a central axis and a major face extending in a radial direction from the central axis. The optical disk is rotatable around the central axis at an angular velocity and is formed with a recording layer on the major face. The recording layer is optically recordable with information and is formed with a track area containing tracks which are arranged at a predetermined track pitch in the radial direction and which are accessable by an optical beam to read or write information while the tracks move at a linear velocity relative to the optical beam. The recording layer is preliminarily recorded with control information indicative of the predetermined track pitch and/or either of a predetermined linear velocity of the tracks or a predetermined angular velocity of the disk. The control information is readily readable from the recording layer to facilitate the accessing of the tracks by the optical beam.

Abstract: A strategy process used for recording data on an optical disk is also used during DC erase is performed. Effects similar to those obtained in the case, in which a high frequency signal is superposed on a laser diode output current during the DC erase, can be obtained by performing the strategy process on the laser diode output current during the DC erase. This eliminates the necessity for generating high-level and high-frequency signals. Consequently, an apparatus can be constructed at low cost.

Abstract: An optical disk recording apparatus operates on an optical disk having circular tracks which are provisionally written with an index signal used for securing a constant linear velocity of the optical disk from an innermost circular track to an outermost circular track, and records data along the circular tracks at different linear densities on different annular zones of the optical disk. In the apparatus, a disk drive section rotates the optical disk while synchronizing the index signal successively read from the rotated optical disk with a predetermined reference clock signal to thereby maintain the constant linear velocity of the circular tracks. A clock generating section multiples or divides the reference clock signal by different rates to generate different writing clock signals in correspondence to the different annular zones of the optical disk.

Abstract: An optical disk includes a standard area of a standard recording density provided on an inner peripheral side and a high density area of a higher recording density provided on an outer peripheral side. In each of the standard area and the high density area, a program area is provided so that an independent program can be recorded in each program area. In one aspect of the invention, an optical disk includes, from the inner periphery to the outer periphery of the disk, a ROM area for read-only purpose, a RAM area in which information can be rewritten and a WO area in which information can be written only once.

Abstract: An optical disk includes a standard area of a standard recording density provided on an inner peripheral side and a high density area of a higher recording density provided on an outer peripheral side. In each of the standard area and the high density area, a program area is provided so that an independent program can be recorded in each program area. In, one aspect of the invention, an optical disk includes, from the inner periphery to the outer periphery of the disk, a ROM area for read-only purpsoe, a RAM area in which information can be rewritten and a WO area in which information can be written only once.

Abstract: Test-recording signals are recorded onto an optical disc by variously varying the intensity values of erasing power and bottom power as well as writing power of a laser light beam, in order to determine a combination of optimum intensity values of the writing power and erasing power, of the writing power and bottom power or of the writing power, erasing power and bottom power. Then, actual-recording signals are recorded in accordance with the thus-determined combination of optimum intensity values. With this arrangement, optimum recording conditions can be constantly provided irrespective of non-uniform and time-varying characteristics of various optical discs used, and it is possible to reliably prevent reproduction errors or failure of reproduction.

Abstract: Test EFM signal reproduced from an optical disk is converted through a slicer into binary value, and a synchronizing signal having an 11T--11T signal pattern is detected by a frame synchronization circuit. Upon detection of the synchronizing signal, a detection timing counter predicts timing when a next synchronizing signal will be detected. The respective level values at the intermediate points of the former and latter 11T sections of the synchronizing signal are sampled and held by sample and hold circuits. Once a next synchronizing signal is detected at the predicted timing, a synchronization determination circuit transfers the outputs of the sample and hold circuits to another sample and hold circuits. The outputs of the other sample and hold circuit are averaged by filters and asymmetry is calculated by an asymmetry calculation circuit. On the basis of the calculated asymmetry, a determination circuit determines an optimum recording power value.

Abstract: EFM input signal is received via an EFM input interface. Recording-timing adjustment data is received via a computer interface from a computer and stored in a register. To obtain EFM output signal having its pulse duration controlled on the basis of the EFM input signal and the record-timing adjustment data, there are further provided a clock signal generation circuit for generating clock signal by a phase-locked-loop arrangement based on a crystal oscillator, a first pair of counter and comparator driven by the clock signal to determine the pulse duration of a signal to be written, a second pair of counter and comparator that is driven by the clock signal and responsive to the output from the comparator of the first pair to start counting so as to determine a pulse duration to be adjusted, and a flip flop that is reset by the output from the comparator to provide an EFM output signal having a controlled pulse duration.

Abstract: An optical disc recording system can record data on a writable type optical disc and reproduce the recorded data by utilizing a playback device adapted exclusively for playing back a standardized unwritable optical disc such as a Compact Disc. The optical disc recording system comprises a recording medium and a recording device. The recording medium consists of an optical disc having its recording surface made of a material which is writable with a semiconductor laser and has a relatively high rate of laser beam reflection, having a mechanical size like or compatible with the standard size of an optical disc for playback only and having a pregroove of a relatively small depth.

Abstract: An optical disc recording device comprises laser beam control means or a mark length recording type which records data by forming pits on an optical disc by radiation of laser beam for periods of time corresponding to pit lengths of respective pits. The laser beam control means shortens radiation time of laser beam as pit length of a pit to be formed increases. The laser beam control means also shortens radiation time of laser beam as immediately preceding blank length of a pit to be formed decreases. The shortening of the radiation time cancels tendency to increasing of pit length whereby a pit of pit length which is close to a set value can be formed. In one aspect of the invention, the laser beam control means advances starting of radiation of laser beam as immediately preceding blank length of a pit to be formed increases.