Abstract: On an information recording medium (1), digital information is multi-level-recorded by changing a shape of an information pit in correspondence with the digital information by multiple steps.

Abstract: An optical pickup is provided which includes a light source, an optical system for converging a laser beam emitted from the light source, and an optical element having a function of increasing a numerical aperture of the optical system, wherein recording and/or reproducing information on a recording medium is performed by using the laser beam from the light source while the optical element is brought in contact with or in close to the recording medium, and the optical element has a contamination-preventing structure.

Abstract: An optical disc apparatus includes a fixed portion having a light source portion and a movable portion that holds an objective lens and moves along a radial direction of an optical disc. The fixed portion includes the light source portion for selectively emitting short and long wavelength laser beams, and a collimator lens for collimating the laser beams. The objective lens includes a positive refractive lens and a diffractive lens structure formed on a surface of the refractive lens. The diffractive lens structure has wavelength dependence such that spherical aberration varies in the undercorrected direction as wavelength of incident light increases. The objective lens converges the short wavelength laser beam of a predetermined diffraction order onto an informatlon layer of a thin cover type optical disc, and converges the long wavelength laser beam of the identical diffraction order onto an information layer of a thick cover type optical disc.

Abstract: A method and apparatus for recording and storing information on and reproducing information from a storage medium is described, wherein the active storage medium forms part of the write/read signal path.

Abstract: There is provided an adaptive recording method for recording binary data having marks and spaces by irradiating a light signal onto an optical recording medium and adaptively adjusting the power of the light signal according to the correlativity between the length of a mark currently being recorded and the lengths of leading/trailing spaces, the adaptive recording method including the steps of (a) checking the output characteristics of a light signal generating apparatus for generating the light signal, and (b) controlling the power of the light signal by referring to the power of the light signal corresponding to the correlativity and the output characteristics in recording the data on the optical recording medium. The adaptive recording method allows accurate recording control by updating light output control data with respect to a power setting value according to variation in the output characteristic of the laser diode.

Abstract: There is provided a disk drive unit which is capable of making control corresponding to contaminant and defect by discriminating the contaminant (dust, scratch) on the disk surface from the defect on the recording plane. In a pull-in signal PI corresponding to reflected light from a disk, a defect detecting signal corresponding to a signal whose level change is relatively quick corresponding to the defect of the recording plane and a contaminant detecting signal which corresponds to a signal whose level change is relatively slow corresponding to the contaminant on the disk surface are generated. When the defect detecting signal is at low level for example, a system controller retries a recording operation or increases laser light when the contaminant detecting signal is at low level. A quantity of output light of a laser diode is controlled so that a product of output light of a laser diode and reflected light from the disk amounts to a predetermined level.

Abstract: An optical head according to the present invention includes: a first light source for emitting light with a first wavelength; a second light source for emitting light with a second wavelength longer than the first wavelength; and an objective lens for focusing the lights with the first and second wavelengths on information recording surfaces of information recording media corresponding to the lights with the respective wavelengths. The objective lens is designed so as to reduce aberration with respect to the light with the first wavelength. An optical-path length from the second light source to the objective lens is allowed to be shorter than that from the first light source to the objective lens so that aberration caused by the objective lens due to chromatic dispersion caused by a material of the objective lens is reduced with respect to the light with the second wavelength.

Abstract: An apparatus for scanning optical recording media, having a detection unit with a photodetector and a reference voltage associated therewith, an evaluation unit having an input, and a connection disposed between the detection unit and the input of the evaluation unit. In such scanning apparatuses, voltage coupling is usually provided between the detection unit and the input of the evaluation unit. Such a coupling arrangement has the disadvantage that the two units must operate in approximately the same voltage range. In the scanning apparatus according to the present invention it is not necessary for the detection unit and the evaluation unit to operate in substantially the same voltage range. According to the present invention, the evaluation unit has a controller, that holds the input of the connection at the value of a reference voltage of the detection unit.

Abstract: Correction for harmonic disturbances on rotating storage media in a phase-locked loop. The effects of harmonic disturbances in a phase-locked loop are reduced by employing harmonic correction. Harmonic correction may be present in the loop at all times, or may be switched in once the loop has achieved phase lock. Disturbance within the loop bandwidth is corrected using additional integrating pole or a bump (resonant) filter. Disturbance outside the loop bandwidth is corrected using low pass or a notch (anti-resonant) filter. Alternately, a canceling signal may be generated and added as a feedforward signal. A repetitive control scheme uses a filtered version of the residual errors on previous media rotations as a feedforward signal to cancel harmonic effects.

Abstract: A system and related methods for characterizing and improving optical drive read performance is presented. The system includes an innovative audio file stored on optical media (characterization file), and an optical drive characterization agent, implemented on a computing system. The optical drive characterization agent iteratively controls the optical drive to perform incremental reads of at least a subset of the characterization file, analyzes at least the subset of the characterization file read from the optical media, and generates one or more performance scores on an associated one or more performance attributes of the optical drive. In this regard, optical drive characterization agent quantifiably characterizes an optical drive's ability to accurately read individual sectors from optical media comprising audio content.

Abstract: When a deviated gravity disc is reproduced at a higher rate with the disc reproducing apparatus, an excessive vibration is generated and this vibration gives adverse effect on the disc reproducing apparatus and peripheral components/apparatuses, and/or may represent an annoyance to a user. A vibration information detector for detecting vibration of the disc reproducing apparatus or a deviated gravity information detector for detecting amount of gravity deviation of disc is provided, and as a result of such detection of an imbalance (i.e., excessive vibration or mass eccentricity), and a reproducing rate switching control controls sets and limits the reproducing rate of the disc reproducing apparatus to a substitute speed which is lower or higher than a normal reproducing speed.

Abstract: When an optical disk is loaded, the light source provided with the optical head for the CD and the light source provided with the optical head for the DVD simultaneously irradiate the laser beams of different wavelengths each toward the optical disk D. And, the optical heads for the CD and DVD are simultaneously driven in parallel in the focusing direction. At that moment, the optical head for the CD and the optical head for the DVD simultaneously detect all the signals added and the RF envelopes individually, which are stored in the memory at the same time. All the signals added and the RF envelopes stored in the memory are sent to the control unit, where a specified processing is carried out to identify the specification of the disk.

Abstract: This invention relates to a servo-control method and servo-controller of a memory storage device, as well as the memory storage device, for positioning the reading position of a head on a target position. It suppresses phase lag in the high region while preventing a decrease in follow-ability. This invention comprises a storage medium 72, head 76, actuator 60, detection circuit 48, and control circuit 16. The detection circuit 48 detects the amount of shift between the reading position of the head 76 and a target position. The control circuit 16 performs PID calculation for the shift amount and outputs an instruction value for the actuator 60. There is a limiter 121 for limiting the calculated result of the differential component of this PID calculation to a specified value. Only the high region is limited and the low region is not limited, thus it is possible to suppress phase lag in the high while maintaining follow-ability.

Abstract: A recorded medium reproducing apparatus that is capable of loading a plurality of various types of recorded media, and is such that it is possible to simultaneously display, in an easy-to-understand form for the user, for each recorded-medium accommodating unit whether or not it contains a recorded medium, and the type of recorded medium accommodated.

Abstract: The invention provides an optical disk recording and reproduction method which suppresses a drop of the throughput of an optical disk apparatus by retrying caused by a read error. A control section of an optical disk apparatus controls, if a read error occurs upon reading out of data from a first address of an optical disk by an optical head section, the optical head section to perform retrying of reading out from the first address. Each time retrying is performed, the control section records the number of times of retrying into a memory. Then, if reading out from the first address is performed successfully, then the control section reads out the number of times of retrying from the memory. If the number of times of retrying exceeds a prescribed number of times then the control section secures an alternative second address in place of the first address on the optical disk.

Abstract: A process and device are provided for controlling an incident optical beam for reading a track of a dynamic medium, e.g. a digital disc, having information stored therein. The beam reflected by the disc is picked up by an optical pickup having several photodetectors and the positioning error of the beam with respect to the track is determined from elementary signals delivered respectively by the photodetectors and from an overall signal containing the information and delivered by the pickup.

Abstract: Beam shaping means may have a shaping ratio set to allow a light beam emitted from a semiconductor laser and having an elliptic intensity distribution to have an ellipticity of no more than two to obtain a spot achieving high light availability and reduced in size. Furthermore, the shaping ratio can be set to no more than 2.5 to allow a polalized-beam splitter (light separation means) and other components to be arranged in a converged flux passing between the semiconductor laser and a collimator lens.

Abstract: An optical recording/reproducing apparatus forms multiple marks with nine mutually different lengths, which are represented as 3T through 11T according to an eight-to-sixteen modulation coding technique, in an information layer of a rewritable information carrier by irradiating the information layer with a pulsed radiation beam. A test mark with a length equal to or greater than 7T is once recorded in the information layer, a signal associated with the test mark is read out and then an average power of the pulsed radiation beam is corrected to uniformize the widths of marks with various lengths of 7T more. This correction may be performed by partially increasing the power of the radiation beam represented as a multi-pulse train.

Abstract: According to the invention, techniques for minimizing power consumption in optical disk drives. Embodiments according to the present invention can provide disk drives with optimal positioning of a fixing part of an objective lens driving unit incorporated therein. Spatial location of magnets can also be determined in order to reduce the power consumption and the torsion of the lens.

Abstract: An optical disk reproduction apparatus comprising a microcomputer (7) for resuming reading data from an optical disk (1) when buffering to a memory (6) is interrupted, a continuous data detector (55) for dividing first data buffered in the memory (6) before the buffering interruption and second data read out in accordance with an instruction from the microcomputer (7) into “n” groups, respectively, and detecting whether the first data and the second data are in coincidence for each group, and a buffering resumption request generating circuit (56) for instructing a timing of buffering resumption on the basis of a result of the continuous data detector (55).