Abstract: A disk drive apparatus for recording (writing) and/or reproducing (reading) information on an optical disk by rotating the optical disk, and adjusting the tilt angle of an optical pickup device with respect to the optical disk. A spindle chassis rotationally supports a turntable on which the optical disk is placed. A pickup chassis, rotationally supported on said spindle chassis, movably supports an optical pickup device that writes and/or reads the information to/from the optical disk and is movable toward and away from the turntable. A tilt mechanism adjusts the tilt angle of the optical pickup device with respect to the optical disk by rotating the pickup chassis with respect to the spindle chassis.

Abstract: The object of the present invention is to provide an optical recording method for recording data in an optical recording medium, which can reduce jitter of a reproduced signal even in the case where data are recorded at a plurality of linear recording velocities. The optical recording method according to the present invention can record data at a plurality of linear recording velocities or a continuously changing linear recording velocity and a recording waveform for modulating a recording beam includes a direct current section and a recording pulse section. Data are recorded so that the intensity Pbi of the direct current section and the intensity Pw of the recording pulse section satisfy PbiH/PbiL<1 and (PbiH/PwH)/(PbiL/PwL)<1 where PwL and PbiL are Pw and Pbi when data are to be recorded at a linear recording velocity VL and PwH and PbiH are Pw and Pbi when data are to be recorded at a linear recording velocity VH higher than the linear recording velocity VL and satisfying 1.1?VH/VL.

Abstract: A user-interactive program assists a user in locating files on optical media discs such as CD-ROMs and DVDs to enhance file-transfer rates and program installation times in computers with a Constant Angular Velocity (CAV) optical media disc drive. In addition, an application program calculates an optimal location for files and/or directories on an optical media disc so that the files are located near the location with the highest data transfer rate. This program may be used to compute an image file that defines where data will be located on an optical disc, or may be used to control transfer of data to the optical media disc.

Abstract: The method for reproducing records for the optical recording medium detects and compensates for detrack, tilt and defocus, having advantages in that: (1) the magnitude and the direction of detrack, tilt and defocus can be detected from a difference signal (for example, a read channel 2 signal or a tracking error signal obtained by processing the read channel 2 signal) between optical reflecting signals detected at the header fields staggered on the basis of the tract center, and compensates for detrack, tilt and defocus, thereby preventing deterioration of data quality caused by detrack, tilt and defocus during a recording/reproducing operation and enabling the stable operation of the system; and (2) the focus servo is rapidly stabilized to enable real-time recording as well as the stable operation of the system.

Abstract: An integrated unit in which a light source and a light emitting diode are combined into one component is fixed to an optical bench. Then, relative position adjustment of an objective lens actuator is carried out with respect to the optical bench so that a desired detection signal can be obtained through reflected light from a disk information recording medium and then the objective lens actuator is fixed. The relative position adjustment of the integrated unit is no longer required and it is no longer necessary preliminarily to provide a margin for adjusting the integrated unit. Thus, an optical head can be reduced in size and thickness.

Abstract: The invention relates to a method for the recording and reading of data with a holographic write/read apparatus onto a holographic recording medium with a thin holographic recording layer. The medium is preferably an optical card (2). The recording of the information is in the form of data pages stored as thin Fourier holograms (61). According to the invention, it is foreseen to use reflected transmission and polarisation holography with different write and read wavelengths, and to correct during reading the distortion in the readout channel caused by the difference between the write and read wavelengths. The invention further relates to an apparatus and system for performing the method. There is also disclosed a method of coding the recorded information.

Abstract: An optical pickup for reading information written on an optical disk is equipped with a laser diode having a front facet which emits light, a parallel light ray portion which collimates the emitted light from the laser diode, means for focusing collimated output light onto the optical disk, means for receiving reflected light from the optical disk, and an optical element having an index of refraction of 1 or higher for adjusting the length of the optical path between the front facet of the laser diode and the optical disk, wherein the optical element is inserted in the parallel light ray portion when the optical path length lies within the range of the expression“(n?0.5±0.25)×the effective cavity length of the laser diode” (where n is a positive integer) in order to reduce the noise in the emitted light of the laser diode.

Abstract: An optical information recording method and apparatus which records information on a recording medium by irradiating the recording medium with an irradiation light of a recording power to form a recorded-mark on the recording medium such that reflection coefficient from an area of the recorded-mark is different than a reflection coefficient from an area of the recording medium where the recorded-mark is not formed by a changing power of the irradiation light.

Abstract: Apparatus nominally used for recording includes a reproduction section to play digital data from a recording medium recorded with that digital data and retrieval information, a recording section to write the digital data reproduced by the reproduction section and record the retrieval information on a control table, and a control circuit to search the control table by using the retrieval information when the digital data from the reproduction section is written by the recording section, thereby to permit the writing of digital data recorded on the medium with the recording section when the retrieval information is not recorded on the control table, and to prohibit the writing of digital data recorded on the medium with the recording section when the retrieval information is already recorded on the control table, and also to prevent the mistaken duplicate copying of the digital data with the recording section.

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: An optical information recording apparatus can maintain a stable recording quality when recording information on an optical information recording medium having a recording layer of a multilayer structure. An optical information recording medium of a rotating type has a plurality of recording layers each having an information recording area in which information is recorded using a laser beam. An inner power calibration area is provided in each of the recording layers at a location closer to a center of rotation of the optical information recording medium than the information recording area, and is used to perform a test write in an optimum power control process to acquire an optimum recording power of the laser beam. The outer power calibration area is provided at a location farther from the center of rotation than the information recording area, and is used to perform a test write in an optimum power control process to acquire an optimum recording power of the laser beam.

Abstract: The present invention relates to an optical pickup and an optical disc drive that records or reproduces data signals on or from optical discs different in specifications, such as recording density and thickness. One objective lens (17) is used for optical discs (22a, 22b) of two types that differ in specifications. The optical pickup and the optical disc drive comprise two light source sections (24a, 24b) and a lens-supporting mechanism (15). The light source sections emit two laser beams of different wavelengths, respectively. The lens-supporting mechanism (15) controls the position of the objective lens (17) in the radial direction of the discs and along the optical axis.

Abstract: The present invention provides an optical disc apparatus capable of rotating an optical disc with high speed while enabling reduced current consumption. The optical disc apparatus comprises a spindle motor for rotating the optical disc and a thread motor for driving an optical pick-up. When a command is received while the spindle motor is driven, a controller delays operation of the thread motor for a predetermined duration to allow operation of the spindle motor rather than immediately activating the thread motor. After the predetermined duration has elapsed, the controller activates the thread motor and halts the operation of the spindle motor. The predetermined duration may be either a fixed value or a variable value established so as to become smaller as rotation speed of the optical disc increases.

Abstract: A track management method includes steps of obtaining track information from a play order table having track information entries arranged in a predetermined play order, the track information corresponds to a track to be deleted and points to a track descriptor in a track information table; obtaining the track descriptor, the track descriptor including a decryption key corresponding to the track to be deleted and pointer information that points to one of a plurality of part descriptors in a part information table; advancing the predetermined play order for a subset of the plurality of track information entries that follow the track to be deleted in the predetermined play order; reading the one of a plurality of part descriptors; separating in a file system a data block that is a part of a file specified by part pointer information in the part descriptor from the file managed by the file system and freeing the data block on the file system, the part pointer information pointing to a part of the file that includ

Abstract: A recording medium storing a write protection information, and a write protection method for protecting data recorded on a recordable and/or rewritable disc from unwanted overwriting or erasing. In order for write protection of a disc in a bare state that is usually used in a cartridge having a recognition switch for write-protection, such as a DVD-RAM, write protection information is recorded in a Lead-in area, a Lead-out area or a recording information area other than a user data area of the disc, and the data is protected from unwanted overwriting or erasing using the write protection information. Also, even though the write protection information stored on a disc does not match the state of a recognition switch of a case for write-protection, the data can be prevented from unwanted overwriting or erasing. Thus, the write protection can be ensured when a recordable and/or rewritable recording medium, such as DVD-RAM, DVD-R and DVD-RW, is used in a bare state.

Abstract: An optical pickup apparatus includes a first light source to emit a first light beam having a predetermined wavelength, a first optical path changer to change a proceeding path of the first light beam, an objective lens to focus the first light beam on a recording medium, a diffraction member to divide the first light beam reflected by the recording medium into five light regions, the diffraction member having a first diffraction region having a wide width in a direction corresponding to a tangential direction of the recording medium and second through fifth diffraction regions sequentially arranged around the outside of the first diffraction region in a direction corresponding to a radial direction of the recording medium, and a first photodetector having first through fifth light receiving portions to receive the first light beam reflected by the recording medium.

Abstract: A method and an apparatus for detecting a number of variation in resistance within a material stack in response to a scanning and injection of a non-contacting electron stream into a material stack, the material stack having a first conductive contact layer, a variable resistive layer, a fixed resistive layer, and a second conductive contact layer, and the variations in resistance within the material stack being based on one of a plurality of resistive states of the variable resistive layer. The method also includes generating two magnetic fields within a transformer, the transformer being operatively coupled to the first and second conductive contact layers and generating a differential output signal within the transformer based on the two magnetic fields, the differential output signal being associated with one of the plurality of resistive states.

Abstract: A magneto-optical recording or reproducing device having an information erasing means for erasing information or data recorded on a magneto-optical recording medium. According to the invention, the information erasing means comprises an erasing magnet having a field strength sufficient to initialize the magneto-optical recording medium without the assistance of a laser and/or an optical scanning device.

Abstract: Plural grooves or lands formed in an information recording carrier include at least a wobbling region and data is recorded wobblingly in this wobbling region by phase shift modulation while recorded digitally with a single or multiple waves as a channel bit.

Abstract: It is an object of the present invention to provide an information recording and reproducing technique capable of improving the reliability of information recorded on a recording medium. A recording condition comprising amplitude information and the ratio of the amplitude to the recording power is previously recorded on the recording medium. Using this previously recorded information, information is recorded and then immediately reproduced to calculate the optimum recording power from the amplitude information obtained from the reproduced signal. By adapting the recording condition accordingly, it is possible to secure reliability of information in performance.