Abstract: During a normal operation, a tracking control signal from a tracking controller is supplied to an adder via a first switch and to a radial deviation component detector. The radial deviation component detector determines a radial deviation component EC of AC caused by radial deviation of an optical disk from the tracking control signal and supplied that component to the adder via another switch. For a track jump, the first switch is turned OFF, cutting off the tracking control signal. Thus, the radial deviation component EC and a jump pulse signal from a jump signal generator are added together by the adder. However, an offset of the tracking control signal TC detected by a DC component detector is further added. To avoid instability, the track jump is compensated so as to be normally carried out even if a DC offset is added to a tracking control signal.

Abstract: A disk drive apparatus for a disk having helically-formed or concentric circle-like formed tracks includes a spindle motor for controlling a rotation of the disk; a pick-up device for recording or reproducing information on or from the disk; a stepping motor for moving the pick-up device in a radial direction of the disk in accordance with a drive current; a system controller for tracking a rotation speed of the spindle motor and for outputting command signals according to the rotation speed of the spindle motor; and a stepping motor controller for controlling the stepping motor by changing a slope of a rising part and a falling part of a waveform of the drive current of the stepping motor according to the command signals.

Abstract: In a medium having a restriction on its function which has an extremely low overwrite cyclability as compared with a common one, information is arranged so as to allow restricted write and read operations in a commonly current write and read drive, i.e., the medium is subjected to specific formatting. It is possible to perform write and read operations with security. The specific format can be performed with parameters taking the special-purpose using conditions (i.e., overwrite cyclability) into consideration. Consequently, it becomes possible to provide a low-priced information recording medium.

Abstract: In a medium having a restriction on its function which has an extremely low overwrite cyclability as compared with a common one, information is arranged so as to allow restricted write and read operations in a commonly current write and read drive, i.e., the medium is subjected to specific formatting. It is possible to perform write and read operations with security. The specific format can be performed with parameters taking the special-purpose using conditions (i.e., overwrite cyclability) into consideration. Consequently, it becomes possible to provide a low-priced information recording medium.

Abstract: An information record and playback apparatus has a user information acquisition unit for acquiring user information of the user using the apparatus at present; a record unit for recording the acquired user information and playback stop position information on a record medium in relation to each other; and a playback start control unit for selecting the playback stop position information corresponding to the acquired user information from among the playback stop position information read from the record medium and resuming playing back the record medium based on the selected playback stop position information.

Abstract: A rewritable recording medium having a first adjustment region recorded with first signal information, a data portion recorded with data information after the first adjustment region, and second adjustment region recorded with a second signal information after the data portion. Each time the first signal information is rerecorded, a length of the first adjustment region changes and a start position of the first adjustment region changes.

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 method for recording information on a rewritable recording medium includes recording synchronizing signal information in a synchronizing signal portion on the medium, recording data information in a data portion of the medium after the synchronizing signal portion by forming marks in the data portion, and substantially randomly inverting the marks and spaces between the marks each time the information is recorded. The marks for particular areas of the medium are different in a physical property from other areas of the medium and data information is recorded in association with both ends of each of the marks. Upon rewriting of at least the recorded synchronizing signal information, a length of the synchronizing signal portion changes and a start position of the synchronizing signal portion changes, and wherein a change of the synchronizing signal information start position is smaller than a change of the length of the synchronizing signal portion.

Abstract: In a magneto-optical recording medium, a first magnetic layer is made of a material using a Gd—Fe film or a Gd—Fe—Co film as a base so that a magnetic field normalized based on saturation magnetization of a magnetic domain wall driving field can be larger than 1, and an element concentration ratio (at. % ratio) of Gd to Fe or Fe—Co is set in a range of 28.0?Gd?29.0. A second magnetic layer is made of a material using a Tb—Fe film or a Dy—Fe film as a base, to which a nonmagnetic element such as Al or Cr, and Co are added. A third magnetic layer is made of a material using a Tb—Fe—Co film or a Dy—Fe—Co film as a base, and an element concentration ratio (at. % ratio) of Tb or Dy to Fe—Co is set in a range of 23.5?Tb?25.5 or 25.5?Dy?28.5.

Abstract: A high density disc having a data area which is set such that compatibility is secured in the same drive while maintaining a superior recording/reproducing feature, is disclosed. The high density disc has a center hole, a clamping area, a data area where user data is recorded, a lead in area located at the inner side of the data area, and a lead out area located at the outer side of the data area. In the high density disc in which the diameter of the center hole is 10 mm or more, the inner diameter of the clamping area is characteristically within a range of 20–26 mm. Also, the inner diameter of the data area is characteristically within a range of 35–40 mm. Therefore, while a conventional disc drive is still used, the size of the high density disc decreases and a recording capacity can be increased.

Abstract: Methods and apparatus for using physical synchronization markers during optical disc data acquisition are provided. In accordance with this invention, physical synchronization markers on optical discs and/or disc covers can be used to determine absolute and/or relative positions on the disc or cover and control data acquisition. A method for acquiring data includes detecting at least one physical synchronization marker and reading data in response to detecting the marker.

Abstract: Methods for controlling the position of a plunge mechanism which is mounted to a cartridge engaging assembly are disclosed herein. In one method, the position of a plunge mechanism associated with a cartridge engaging assembly is regulated by 1) providing a reference mark on the plunge mechanism, 2) detecting a size of the reference mark on the plunge mechanism, and then 3) determining the position of the plunge mechanism based on the size of the detected reference mark. In another method, a plunge mechanism is moved to an extended position within a cartridge engaging assembly by 1) initiating movement of the plunge mechanism from a retracted toward an extended position in accordance with an open loop control schedule, and then 2) after moving the plunge mechanism for a predetermined distance, switching control of the movement of the plunge mechanism to a closed loop control schedule, and monitoring a detector which detects a reference mark provided on the plunge mechanism.

Abstract: A recording and/or reproducing apparatus for recording and/or reproducing signals on and/or from a recording medium includes a recording and/or reproducing portion for recording and/or reproducing signals on and/or from the recording medium, a carrying portion for carrying the recording medium, and first and second sliders. The first slider is movable in one direction for moving the carrying portion together with the recording medium up to a specific withdrawal position. The second slider is movable in a direction being substantially the same as the one direction for moving the recording medium carried by the carrying portion to a recording and/or reproducing position corresponding to a position of the recording and/or reproducing portion. The first slider and the second slider are overlapped to each other in the vertical direction.

Abstract: A disk apparatus includes a pick-up for reading/writing signals from/on a disk; a pick-up base provided with the pick-up; a traverse motor for moving the pick-up in a radial direction of said disk; a feed screw rotated by the traverse motor and provided with a thread groove on its periphery; a rack having a fixing portion fixed to the pick-up base and a nut portion engaged with the thread groove; a guiding mechanism for guiding the pick-up movably in a radial direction of the disk; and a cantilever parallel spring for connecting the fixing portion to the nut portion of the rack, displaceably in a radial direction of the feed screw.

Abstract: An optical disc drive 1 of the present invention can record and/or reproduce data including audio data and non-audio data onto and/or from a multi-session optical disc 2 when the optical disc is loaded into the optical disc drive.

Abstract: An optical disk, a recording apparatus and playing apparatus which can record various kinds of identification information in the form of a pit train and a bar code without decreasing the data recording area for main information. Both a first data block including a pit train indicating first identification information and a second data block including a bar code indicating second identification information are formed in the recording part at the same radius.

Abstract: A disc which insures a normal performance of an optical disc driver (ODD) and a method of manufacturing the same by accounting for disc defects. A reflectivity of the disc is within a range of 45–70% and a birefringence of the disc is within a range of 100–150 nm. Since the acquisition and manufacture of marginal discs which account for defect factors are possible, the influence of the defect factors can be continuously limited. Thus, a predetermined quality of discs can be used in the ODD.

Abstract: A method of reading out data from a domain expansion data storage such as a MAMMOS magneto-optic disk (1) which includes a data storage layer in which data is stored in the form of magnetic marks, and an expansion layer capable of copying and expanding domains from the storage layer, the system applying a first radiation beam (7), having a first spot size on the disk, in order to initiate copying of a domain from the storage layer to the expansion layer, and applying a second radiation beam (9), having a second spot size larger than the first spot size on the disk, in order to read out data from the expansion layer.

Abstract: A dielectric part 4 comprising a nitride layer 7 and an oxide layer 8, laid one upon the other, is formed on a data-recording layer 3. A light-transmitting layer 5 is boned with adhesive to the dielectric part 4. Since the dielectric part 4 is interposed between the data-recording layer 3 and the light-transmitting layer 5, the organic material of the data-recording layer 3 does not diffuse into the adhesive that bonds the light-emitting layer to the dielectric layer 4. Additionally, the data-recording layer 3 is not deteriorated due to the oxygen plasma generated during the process of forming the oxide layer 8, because the oxide layer 8 is provided on the nitride layer. Since the nitride layer 7 has a thickness of 10 nm or less, it does not influence optical enhancement effect.

Abstract: An optical pickup apparatus conducts recording or reproducing information for an information recording plane of a first or second optical information recording medium and comprises a first light source and a second light source mounted on a same base board; a converging optical system; and a coupling lens. The converging optical system comprises an objective lens to converge a first or second light flux having passed through the coupling lens on a first or second optical information recording medium; and a diffractive structure to change a focal length in accordance with a wavelength of a light flux emitted from the first light source or the second light source.