Abstract: An apparatus and method for detecting and replacing a defective sector on an optical disk. Recording data and error correction data are recorded on an optical disk at a manufacturing time or an initial time. The recorded data and the error correction data are reproduced in units of one sector. A defective sector is determined when address data in an address field cannot be reproduced or when a number of errors in at least one sector exceeds a specified value. Address data of the defective sector is recorded in a defect list on the optical disk. Recording data and error correction data are successively recorded on the optical disk in a plurality of successive block areas. Defective sectors are skipped and recording data and error correction data are recorded in a unit of one block beginning in a next sector area.

Abstract: In this invention, in an optical disk on which data is to be recorded in units of one ECC block constructed by 16 sectors, dummy data is recorded at the manufacturing time or at the initial time such as the application starting time, then the dummy data is reproduced to determine a sector with primary defect, the physical address data of the sector which is determined to have the primary defect is recorded in the form of a primary defect list on the optical disk, and at the time of data recording, data recording is effected in units of one ECC block while skipping over the sector with the primary defect. Further, in the optical disk on which data is to be recorded in units of one ECC block, data is recorded at the time of data recording other than the initial time, then the data is reproduced to determine an ECC block having a sector with secondary defect, and data of the ECC block which is determined to have the sector with secondary defect is recorded in an ECC block which is separately prepared.

Abstract: In a case where tracking control is carried out by a lens actuator in performing a tracking pull-in operation in which tracking control is started in the state where tracking control is out of operation, the tracking control circuit brings control into stable tracking control by moving the light spot onto a groove on the optical disc. After that, when tracking onto a land is needed, the tracking control circuit moves the light spot onto the land. This enables a pull-in action toward a stable tracking operation.

Abstract: In this invention, in an optical disk on which data is to be recorded in units of one ECC block constructed by 16 sectors, dummy data is recorded at the manufacturing time or at the initial time such as the application starting time, then the dummy data is reproduced to determine a sector with primary defect, the address of the sector which is determined to have the primary defect is recorded on the optical disk, and at the time of data recording, data recording is effected in units of one ECC block while skipping over the sector with the primary defect. Further, in the optical disk on which data is to be recorded in units of one ECC block, data is recorded at the time of data recording other than the initial time, then the data is reproduced to determine an ECC block having a sector with secondary defect, and data of the ECC block which is determined to have the sector with secondary defect is recorded in an ECC block which is separately prepared.

Abstract: In this invention, when a command indicating movement to a land or groove is output while a beam condensed by an objective lens tracks a groove or land, the polarity is inverted, and a jump pulse is generated. Tracking servo control is stopped during generation of the jump pulse, thereby changing the tracking position from the groove or land to the land or groove. With this operation, the tracking position can be accurately changed from the groove or land to the land or groove for an optical disk having concentric or spiral grooves and lands as recording tracks. Also in this invention, when a switching position is detected while the beam condensed by the objective lens tracks the groove or land, the polarity is inverted. At the same time, tracking servo control is stopped to change the tracking position from the groove or land to the land or groove.

Abstract: In this invention, disk ID data associated with the characteristics of optical disks are recorded on the innermost peripheral portions of a rewritable optical disk and a read only optical disk in advance. The invention can handle both a rewritable optical disk on/from which data is recorded/reproduced by using both a groove and a land, and a read only optical disk on which data is recorded by recording record marks in a mastering process, and can correctly and quickly identify each optical disk.

Abstract: An apparatus for recording data on an M-CAV-formatted optical disk. The disk has a plurality of substantially concentric tracks grouped into a plurality of zones arranged in a radial direction of the disk. Each of the zones is divided into the same number of sectors, each used as a unit area, and has a different assigned frequency at which to read read data from the sectors. Header information is recorded in the start region of each sector and identifies the sector. Provided next to the start region is a data field in which data is to be recorded. The apparatus is designed to record data in the data field by using a master clock signal having a specific frequency assigned to the zone including that data field. The apparatus has a master clock setting circuit for setting the frequency assigned to any zone to which the zone will be switched from the zone in which data is being recorded.

Abstract: A host computer transmits to a disk drive an address or an ID number representing a disk to be used, and the disk drive receives from the host computer the address or ID number representing the disk to be used, wherein when the received address or ID number representing the disk represents a CD-ROM, a reading process for the CD-ROM is executed, and when the received address or ID number presenting the disk represents an R/W-OD, a writing process or a reading process for the R/W-OD is executed.

Abstract: The optical disk formatted by the M.CAV mode has a plurality of tracks for recording data, arranged in a substantially coaxial manner, which are divided into a plurality of zones in its radial direction. Each track is divided into a plurality of sectors, each of which being handled as a unit region for recording data. The tracks in the same zone have the same number of sectors, and tracks in different zones have a different number of sectors. In the header region of each sector, the header data for specifying the sector is prerecorded, and a data field for recording data is provided following this header. In an apparatus for reading out data on a disk formatted as described above, data is read out from the data field based on a data clock having a frequency which varies from one zone to another. When a track of a different zone is accessed, the data of the track is read out based on the clock for reading the target track.

Abstract: An apparatus for recording data on an M-CAV-formatted optical disk. The disk has a plurality of substantially concentric tracks grouped into a plurality of zones arranged in a radial direction of the disk. Each of the zones is divided into the same number of sectors, each used as a unit area, and has a different assigned frequency at which to read read data from the sectors. Header information is recorded in the start region of each sector and identifies the sector. Provided next to the start region is a data field in which data is to be recorded. The apparatus is designed to record data in the data field by using a master clock signal having a specific frequency assigned to the zone including that data field. The apparatus has a master clock setting circuit for setting the frequency assigned to any zone to which the zone will be switched from the zone in which data is being recorded.

Abstract: A signal processing circuit for a disk apparatus with an optical head, which causes photodiodes to detect light acquired by irradiating light from a laser diode on a disk that has an address portion and data portion recorded thereon, and performs photoelectric conversion of the light. A level converter alters the level of the signal detected by each photodiode and provides an output signal. A detector detects a level of the output signal by switching time constants between the address portion and data portion. Using a bias corresponding to the detected level, the levels of signals detected by the photodiodes are changed.

Abstract: Disclosed is an objective lens position detecting system which comprises an optical head for holding an objective lens for focusing a light beam on a storage disk having tracks formed thereon, a first detector having a first light-emitting element and a first light-receiving element and provided in a vicinity of the objective lens, unconnected thereto, for detecting the position of the objective lens, a second detector having a second light-emitting element and a second light-receiving element and provided in a vicinity of the objective lens, unconnected thereto, and apart by a predetermined distance from the first detector, for detecting the position of the objective lens, a plate, connected to the objective lens, for reflecting light from the first light-emitting element to the first light-receiving element and reflecting light from the second light-emitting element to the second light-receiving element, whereby the first detector and the second detector detect the position of the objective lens from values

Abstract: The laser beam control apparatus according to the invention having a photodiode for outputting a current consisting of high and low-frequency components in accordance with the amount of a laser beam emitted from a laser diode. The current output from the photodiode is separated into high and low-frequency components by a CR filter, and the separated low-frequency current is amplified by an amplifier. The current amplified by this amplifier is added to the high-frequency current separated by the CR filter. The resulting sum current is converted into a voltage by an amplifier, and the amount of the laser beam emitted from the laser diode is controlled in accordance with the voltage converted by this amplifier. With this operation, the laser beam output power of the laser diode can be stably controlled in a wide band.

Abstract: A system in which a plurality of devices are connected through an interface bus for transmitting data, which includes a set of termination resistors respectively connected to a plurality of signal lines of the interface bus. The termination resistors are simultaneously switched to valid/invalid states in accordance with ON/OFF control of a 1-bit switch.

Abstract: A recording information apparatus for a recording medium having a track previously formed on the recording medium.

Abstract: An optical disk apparatus for reproducing data from an optical disk having recording tracks emits a laser beam onto the optical disk and converts a reflection beam into an electric signal by an optical head. This electric signal is amplified by an amplifier. The amplifier signal is extracted by the envelope detector. The envelope signal is extracted in accordance with the amplified signal. The envelope signal is added with the amplified signal from the amplifier, and the resultant signal is converted into a binary signal by binary circuit.

Abstract: An optical apparatus for focusing a light beam onto an object having a first track and a second track for guiding the light beam, includes an optical element for directing the light beam onto the object, a detector for detecting the light beam from the object and for generating a tracking-error signal representing a location of the light beam with respect to the first track of the object, and an actuator for moving the optical element from the first track toward the second track. The optical apparatus further includes a generator for generating a track compensating signal corresponding to the distance between the first track and the second track, and an adder for adding the tracking-error signal generated by the detector and the track compensating signal generated by the generator. An adjuster is provided for adjusting the location of the optical element with respect to the second track of the object in response to the signal added by the adder.

Abstract: An optical disk apparatus detects the speed of movement a laser beam gathered and focused by an objective lens from an optical disk. In a coarse access mode, speed control data is read out of a speed control table based upon the number of tracks corresponding to the difference between the present track and a target track. A linear motor, or an optical head coupled with the motor, is then moved in accordance with a difference between the present speed signal as detected and the speed control signal as read out. In a fine access mode, an objective contained in the optical head is moved in accordance with a difference between the present speed signal and the speed control signal.

Abstract: A tracking accessing control apparatus for a light beam for an optical disk having an information recording track in which an apparatus for directing the light beam directs the light beam onto the optical disk. A light beam reflected from the optical disk is detected and a tracking signal, which has a track detection alternating signal and a low frequency component, is generated. A high-pass filter filters out the low frequency component to leave only the track detection alternating signal. The number of alternations of the track detection alternating signal is counted, and the light beam directing means if moved across the tracks according to the number of alternations counted.

Abstract: An apparatus for focusing a light beam onto an object includes a directing element for directing the light beam onto the object, a first detector for detecting the light beam from the object so as to generate a focus signal representing a distance of the directing element with respect to the object. The apparatus further includes a generator for generating a reproduced signal representing the data from the focal signal generated by the first detector. An adjuster adjusts the location of the directing element with respect to the object in accordance with the envelope of the reproduced signal generated by the generator.