Abstract: Methods and devices are described for writing to an optical record carrier, in which a mark representing recorded data is written in a phase-change layer of a record carrier by a sequence of radiation pulses. A rear heating pulse is introduced after a last write pulse and a front heating pulse is introduced before the first write pulse. The power level of the front heating pulse and the power level of the rear heating pulse may be dependent on the length of the mark to be recorded and on properties of the record carrier. The method results in a reduced jitter of the marks written, especially when writing at high recording speeds.

Abstract: An apparatus comprises a slider having an air bearing surface, a first waveguide for directing electromagnetic radiation to a focal point adjacent to the air bearing surface, a storage medium position adjacent to the air bearing surface, a detector for detecting electromagnetic radiation reflected from the storage medium, and a structure positioned adjacent to the focal point for collecting the reflected electromagnetic radiation and for transmitted the reflected electromagnetic radiation toward the detector.

Abstract: An apparatus and method for determining a separation distance between radial locations on a data storage medium, such as an optical disc. A first number of channel bits are detected at a first radial location of the medium, and a second number of channel bits are detected at a second radial location. The radial separation distance therebetween is determined in relation to the respective first and second numbers. Preferably, the first radial location is a first track on the medium, and the second radial location is a second track on the medium. Preferably, a motor rotates the medium, a data transducer transduces readback signals from the first and second locations, and a processor determines the respective numbers of bits from the readback signals. The radial separation distance is preferably used to authenticate the medium.

Abstract: A defect detection device, apparatus, and method for detecting a defect of data recorded on a recording medium. The defect detection device includes a waveform state detection part generating information representing a state of a waveform of a reproduced signal from the recording medium based on soft decision results obtained in a process of reproducing the data in accordance with a maximum likelihood decoding algorithm corresponding to a partial response. The defect detection device includes a defect determination part determining the defect of the recorded data based on the information generated in the waveform state detection part.

Abstract: A slim type optical pick-up actuator is provided. The actuator including: a lens holder provided with an object lens mounted at a predetermined portion thereof, two or more focusing coils received in a receiving groove thereof, a tracking coil disposed on a front surface of the focusing coils, and a tilt coil disposed on a top of the focusing coils, and moving in 3-axis directions; a bipolar magnet disposed facing the coils; two or more unipolar magnets facing the bipolar magnet and having an opposite polarity to the bipolar magnet; a yoke plate having a bent inner yoke, the inner yoke having inner surfaces facing each other, on which the bipolar magnet and the two or more unipolar magnets are respectively attached; and a wire suspension supporting moving of the lens holder and electrically connected to the coils.

Abstract: An optical element for use in an optical pickup device to conduct reproducing and/or recording information for a first disk including a protective substrate by the use of a first light flux emitted from a first light source and to conduct reproducing and/or recording information for a second disk including a protective substrate by the use of a second light flux emitted from a first light source, the optical element includes: an optical surface on which a first phase structure is formed to have a function to correct a spherical aberration; an optical surface on which a second phase structure is formed such that when the wavelength of the first light flux changes, the second phase structure generates a spherical aberration in a direction reverse to the direction of a spherical aberration generated by the first phase structure.

Abstract: Reproduction signals which are simultaneously obtained from an Ach head 3 and a Bch head 4 are time division multiplexed by a signal layout converting circuit 9 and arranged. An HPF unit 12 and an LPF unit 14 of a waveform equalizing circuit 16 are optimally switched on the basis of sync adjustment information such as switching information of the heads. An edge detection pulse width of an edge detecting circuit and an output frequency of a VCO 23 are controlled on the basis of the sync adjustment information. The output frequency of the VCO 23 is used as a clock signal of the reproduction signals by a signal processing unit 27 at the post stage.

Abstract: A data recording method according to the present invention is a method for recording data as edge position information, including marks and spaces of multiple different lengths, on a storage medium by irradiating the storage medium with a pulsed energy beam. The method includes the steps of: (A) generating a write code sequence based on the data to be recorded; (B) determining a write pulse waveform, defining the power modulation of the energy beam, according to the code lengths of respective codes included in the write code sequence; and (C) modulating the power of the energy beam based on the write pulse waveform.

Abstract: A light focusing optical system focuses light, for recording to and/or reproducing from a plurality of optical recording media of different kinds, onto the recording media by using a diffraction element and lens. The diffraction element has at least first and second diffractive surfaces. The first diffractive surface diffracts light whose wavelength is 630 nm or more and 670 nm or less to perform aberration correction on an optical recording medium whose cover layer has a thickness of approximately 0.6 mm. The second diffractive surface diffracts light whose wavelength is 400 nm or more and 415 nm or less to perform aberration correction on an optical recording medium whose cover layer has a thickness of approximately 0.1 mm or approximately 0.6 mm.

Abstract: A tilt detecting apparatus is provided with: a first changing device for changing a focus position of laser light in a lamination direction of recording layers; a second changing device for changing the focus position in a radial direction of the information recording medium; and a tilt detecting device for detecting an amount of tilt, on the basis of a photo-detection signal. Its controlling device controls the first changing device to set the focus position onto one recording layer, controls the second changing device to displace the focus position to a j-th radial direction position (wherein j is a natural number) on the information recording medium, and controls the tilt detecting device to detect the j-th amount of tilt for the one recording layer.

Abstract: A data recording method according to the present invention is a method for recording data as edge position information, including marks and spaces of multiple different lengths, on a storage medium by irradiating the storage medium with a pulsed energy beam. The method includes the steps of: (A) generating a write code sequence based on the data to be recorded; (B) determining a write pulse waveform, defining the power modulation of the energy beam, according to the code lengths of respective codes included in the write code sequence; and (C) modulating the power of the energy beam based on the write pulse waveform.

Abstract: An apparatus for scanning a track on a record carrier has a head (41) for providing a beam of radiation and generating at least one sensor signal. The device has a focusing unit for controlling a focusing element to maintain an in-focus position for generating a focused spot on the track. The sensor signal is converted into a displacement signal by a multitude of piecewise converters (42, 43, 44), each converter converting a range of the sensor signal values into a position signal, and selection means (46) for selecting one of the position signals as the displacement signal based on an estimated displacement.

Abstract: An optical disk unit includes the following: a storage part temporarily storing data to be written to an optical disk; a processing part processing the data; an encoder part modulating and outputting the processed data; a writing control part controlling writing of the data to the optical disk; and a writing command part detecting an occurrence of a state of suspension of supply of the data to the storage part and providing an operation command to the writing control part in accordance with the detection result. In the case of suspending the writing of the data to the optical disk, the writing control part causes the processing and encoder parts to stop accessing the storage part by setting the processing and encoder parts in a wait state after the processing and encoder parts access the storage part, and causes the storing of the data in the storage part to be stopped.

Abstract: An information recording apparatus for recording information on an information recording medium that is recordable is disclosed. The information recording apparatus includes determining means for determining whether specific recording conditions for the information recording medium are recorded at a predetermined area of the information recording apparatus, or externally thereof; recording condition reading means for reading the specific recording conditions when such recording conditions are recorded; first recording means for recording the information based on the specific recording conditions; and evaluating means for performing trial writing test data on a trial writing area of the information recording medium based on predetermined default recording conditions when specific recording conditions are not recorded, and for evaluating a signal obtained by reproducing the test data.

Abstract: A mark S/H circuit (66) samples, for example, a signal A generated as a photodetector (20) detects a return beam from marks of an optical disk (10), a space S/H circuit (68) samples a signal A generated through detection of a return beam from spaces, and amplifiers (70 and 72) justify amplitudes of the sampled A signals from the marks and spaces. A mark/space selector switch (74) selects alternately and combines the mark and space signals whose amplitudes have been justified. After A, B, C, and D signals A1 to D1 are subjected individually to a series of processes up to the combination process, a wobble processing circuit (80) adds them in predetermined combinations, finds differences among the added signals after justifying the amplitudes of the added signals, and thereby reproduces a wobble signal (107).

Abstract: An information playback apparatus comprises an input amplifier to which an RF signal reproduced from an optical disc is input; a high-pass filter to which the output of the input amplifier is input; an AD converter to which the output of the high-pass filter is input; a lag lead filter to which the output of the AD converter is input; and a demodulator for digitally processing the output of the lag lead filter to demodulate it as a binary signal. Thereby, an optical disc playback apparatus that realizes a DVD-RAM playback function at low cost can be realized.

Abstract: An optical disk apparatus is provided with an actuator that moves a beam spot that is formed by an optical head on an optical disk to recording surfaces; position control portions that control a position of the beam spot based on the output signal of the optical head; a disturbance estimation observer relating to the actuator; and a summing circuit that takes a sum of the output of the position control portion and the output of the observer, so as to drive the actuator based on the output of the summing circuit. The optical disk apparatus further is provided with a system controller that turns the observer on and off, a LPF that attenuates the high-frequency components of the output of the observer and retains the final value of the observer when the observer is turned off, and a switching circuit that switches between the output of the observer and the output of the LPF according to whether the observer is on or off.

Abstract: On an optical disc, a record mark having a variable length according to pit data DP is formed at a displaced position to which the record mark is displaced, in a direction crossing the reading direction thereof, according to a wobble signal WB obtained by modulating wobble data DW in a predetermined modulating method. A second wobble synchronization signal D-SYNCw, as a dummy, is recorded on the optical disc, away from the start position of the wobble data DW.

Abstract: The present invention is provided with a detection region for detecting light that is reflected from a first or a second information recording medium and that passes through an optical element. The first information recording medium and the second information recording media are multi-layer disks that have at least two layers, and the detection region includes a detection region (41) for detecting first order and above diffracted light that has a first wavelength, and a detection region (42) for detecting first order and above diffracted light that has a second wavelength.

Abstract: It is an object of the invention to provide an optical information reproducing apparatus and an optical information storing/reproducing apparatus which utilize holography, wherein noise due to reference light is reduced than in conventional apparatuses. An optical system in which arrangement is made so that at least part of a light path of reference light for reproduction is redundant with a light path of reproduction light, and a means to let through the reproduction light and shut out reflected light of the reference light for reproduction, which is reflected by a storage medium on the redundant path are provided.