Abstract: An optical sample includes a mask layer made of a material in which an aperture is produced by a chemical change, which is reversible, upon application of heat or light, and a recording layer provided at a position where an evanescent field produced in the aperture when light is applied to the mask layer can reach. Since the aperture is produced in the mask layer by a chemical change, it can be opened and closed at a high speed and hence a high-speed transfer of information can be achieved.

Abstract: In a laser module holding a semiconductor laser chip and a reflecting surface, to perform positioning on the semiconductor laser chip with high precision, and reduce the period of production, so as to realize downsizing and cost reduction, reflecting surfaces provided on a silicon substrate has a step portion, and the reflecting surfaces are used as reflecting surface for laser emission light and laser chip positioning surface, for high precision positioning. Further, in a laser module which requires a high level power for recording, slopes opposite to side surfaces of the semiconductor laser chip in a lengthwise direction have a step portion, and in wiring of lower electrodes of the laser chip from the bottom of the sink to an upper portion of the silicon substrate, a slope having an angle with respect to the laser chip lengthwise direction is formed as a gentle slope, then wiring is made via the slope, thus mitigating occurrence of migration.

Abstract: An information recording apparatus includes an energy generation device for generating recording energy; a position control device for controlling a position of irradiation on the recording medium with an output of the energy generation device; a drive device for driving the energy generation device; a switching device for switching information based on user data and test information to supply the two kinds of information selectively to the drive device; a reading device for reading the marks recorded on the recording medium; an evaluation device for evaluating a reproduced signal obtained by the reading device; and a recording condition control device for controlling a recording condition on the basis of an evaluation result obtained by the evaluation device, wherein, when the marks used for recording the test information are to be reproduced, controlling operation of the position control device is changed to be different from that used for recording the test information.

Abstract: A tuned circuit is used to detect wobble clock inversions. The tuned circuit reacts to a wobble inversion with a change in amplitude that may be detected by a threshold detector. A bandpass tuned circuit is used to detect wobble clock inversions. The output of the bandpass tuned circuit is input to a saturating high-gain amplifier such as a comparator. The output of the saturating high-gain amplifier reacts to wobble inversions with a half-cycle that has an increased duration as compared to half-cycles without wobble inversions.

Abstract: An optical pickup device employing a signal detection unit including a hologram element having a plurality of pattern regions for diffracting and/or focusing light reflected and incident from a recording medium, a photodetector having a plurality of light receiving regions for receiving and photoelectrically converting the light diffracted by the hologram element and a signal operation unit for generating a focus error signal and/or a track error signal from a signal detected from the photodetector. The optical pickup device can implement a stable servo operation even at deviations of the photodetector, a change in the wavelength of light emitted from the light source, and/or shift of focusing means such as an objective lens, and can record and/or reproduce high-density information on/from the recording medium.

Abstract: A laser drive (LD) unit 1 according to the present invention is provided with a laser drive waveform controller 6, into which information for setting the laser drive is entered from a controller 2, for generating a laser drive waveform on the basis of that information and supplying an indicated amperage; an LD current setting unit 7 for setting a laser drive current matching the indicated amperage; an LD current output unit 8 for varying the laser drive current on the basis of the laser drive waveform and supplying the current so varied to a laser diode 3; and a current setting corrector 9, into which a monitor signal obtained at the time of monitoring the laser beam emission from the laser diode 3 is monitored, for correcting the laser drive current set by the current setting unit 7 by using that monitor signal to adjust the power of the laser diode 3. The laser drive waveform controller 6, current setting unit 7, current output unit 8 and current setting corrector 9 are formed on the same substrate.

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: A CD-ROM drive has a disk tray ejectable from a data transfer position within a casing, where the disk is read, to a load/unload position outside the casing where the disk is loaded on and unloaded from the tray. Being locked in the data transfer position against the bias of an ejector spring, the tray is ejected by being unlocked by brief energization of a solenoid under the direction of a controller. The solenoid might overheat to self-destruction if, upon malfunctioning of the controller, it were left energized after tray ejection. A protection circuit is therefore provided for permitting a solenoid driver circuit to energize the solenoid in response to an ejection command from the controller only when the tray is in the data transfer position.

Abstract: In an optical reproducing device in accordance with the present invention, based on an error rate used in a test read for determining an optimal reproducing power, the value of an error rate corresponding to the maximum burst error which can be corrected by an error correction circuit is obtained. With this structure, an error caused when reproducing power deviates from the optimal reproducing power determined by the test read due to an control error can be corrected by the error detection circuit.

Abstract: An apparatus and method to detect the boundary between a recorded region and a recordable region. When data is recorded on fixed length packets, with each packet comprised of a plurality of blocks, the boundary is determined by a block in which a reading error has occured and that is located at a position distant from a track head by an integral multiple of the packet length. Alternatively, when the blocks are identifiable from among a plurality of block types, the boundary is determined by using the block type of the eroneous block.

Abstract: A result of a blank/written identification performed concurrently with decoding is verified when an error occurs during decoding of read information, and retry is performed according to this identification result in order to achieve fast retry operation. Specifically, a blank check is performed concurrently with decoding of readout data so that when a decoding error occurs, the blank check status can be immediately identified. In this way, suitable retry operations can be undertaken.

Abstract: A recording medium and near-field optical probe utilizing near-field light to achieve high density of information recording and hence enhance resolution in reproducing. A phase shift arrangement layer is formed arranged alternately with a phase shifter region to cause shift by 180 degrees in incident light and a transmission region transparent for a wavelength of the incident light. Furthermore, a row of data marks are arranged in a position above the phase shifter regions and transmission region. Due to this, cancellation is made between spread of near-field light due to incident light transmitted through the phase shifter region and spread of near-field light due to incident light transmitted through the transmission region, providing sharpness in an intensity distribution of near-field light over the data mark. Also, a phase shifter is provided at a through-hole of the near-field optical probe, enabling to produce more localized near-field light.

Abstract: A near-field optical recording apparatus for recording information in a recording medium, and a near-field optical recording and regenerating apparatus for recording information in a recording medium, and reading the information recorded in the recording medium. The apparatuses contain a light source which generates recording light; a micro-aperture probe which has at an end thereof a light-pass aperture having a diameter smaller than a wavelength of the recording light, receives from the other end thereof the recording light, and radiates near-field light on a portion of the recording medium to record the information; and an assistive heating unit which is capable of assistively heating at least the above portion of the recording medium for a duration corresponding to radiation of the near-field light on the portion.

Abstract: Disclosed is a method for controlling track jumps of an optical pickup in gaining high-speed access to a target track freeing from any effects of disturbances, in which time intervals of a TZC (tracking zero cross) signal are measured continuously for comparison between a target time and a measured time required for a track jump by the optical pickup. The difference in time is computed as an error, and a control signal with a voltage or a pulse width reflecting the magnitude of the error is output to an actuator of the optical pickup. In controlling the driving speed of the actuator, the comparison between target and measured times takes into account not only a time difference regarding the preceding track but also time differences with respect to a number of the previous track jumps.

Abstract: A laser drive (LD) unit 1 according to the present invention is provided with a laser drive waveform controller 6, into which information for setting the laser drive is entered from a controller 2, for generating a laser drive waveform on the basis of that information and supplying an indicated amperage; an LD current setting unit 7 for setting a laser drive current matching the indicated amperage; an LD current output unit 8 for varying the laser drive current on the basis of the laser drive waveform and supplying the current so varied to a laser diode 3; and a current setting corrector 9, into which a monitor signal obtained at the time of monitoring the laser beam emission from the laser diode 3 is monitored, for correcting the laser drive current set by the current setting unit 7 by using that monitor signal to adjust the power of the laser diode 3. The laser drive waveform controller 6, current setting unit 7, current output unit 8 and current setting corrector 9 are formed on the same substrate.

Abstract: A disk player for recording or reproducing recording information to a recording disk by emitting a light beam onto the recording disk. The recording disk has a recording track for recording the recording information, a guide track for guiding the light beam to the recording track, and a prepit which is pre-formed on the guiding track and which serves as control information for controlling a recording operation or a reproduction operation of the disk player.

Abstract: In an optical pickup device, the numerical aperture (NA) of an objective lens is set at 0.7 or more, and the ellipticity of polarized light of a light beam which is incident upon the objective lens is set to be larger than (1.4×NA)−0.7. According to the structure, an optical pickup device which can prevent deterioration of the jitter and crosstalk characteristics, for example, due to oval deformation of a beam spot can be provided.