Abstract: A front monitor-type optical pickup apparatus is composed of a window 10w for taking in a laser light beam, and a housing 10 for housing a front monitor detector 9 so as to face the window 10w. In the housing 10, the position of the front monitor detector 9 is adjustable. The optical pickup apparatus makes it possible to eliminate dispersion in quantity of incident light upon the front monitor detector attributed to component and assembly dispersion.

Abstract: An optical recording medium storing information for regarding data in the current sector as data in a linking loss area, and an apparatus and method providing linking data. The data link method includes dividing an error correction code block having a predetermined size into a plurality of sectors and checking data type identification information which indicates whether or not data in each sector is linking data; and replacing main data of a sector with predetermined data according to the result of checking the data type identification information. According to the above method, data type information is checked to determine whether or not to replace main data of the current sector with dummy data. By doing so, error occurrence of the prior art can be prevented and block error correction is carried out more effectively.

Abstract: Upper and lower limit values of disk surface vibration are detected and stored per a predetermined time while a signal is reproduced from an optical disk device and, if focus on the disk deviates from a focus allowable range initially set, a focus repull-in operation is performed with reference to the upper and lower limit surface vibration values stored previously.

Abstract: The invention provides techniques for adjusting for actuator non-linearities in a data storage system. The invention is particularly useful for piezoelectric actuators, such as actuators that implement a bimorph piezoelectric crystal structure or a laminate piezoelectric crystal structure, although other actuators may present similar non-linearity issues. In one embodiment, the invention provides a method comprising applying a signal to an actuator of a data storage system, the actuator having a non-linear response, wherein the signal includes a linear drive component and a non-linear adjustment component, and positioning a data storage head with respect to a data storage medium via the actuator.

Abstract: An optical disk system includes at least one photo detector connected with a variable gain amplifier, a slicer, and a generator which is in the feedback path between the slicer and amplifier. A differential time delay detector provides the output of the optical disk system. The generator is configured for controlling the amplifier non-linearly so that time constants of the control loop of the amplifier which depend upon the level of the input signals are compensated and the timing behavior of the control loop of the amplifier has a more continuous character. A capacitor forms part of an integrator for making the mean value of the output voltage signal of the slicer equal to zero.

Abstract: A mobile communication terminal and a method for reducing power consumption for driving a hard disk drive (HDD) of a mobile communication terminal are provided when controlling an interface between a transition integrated circuit (TIC) that takes charge of the interface with the HDD built in the mobile communication terminal and the HDD. The terminal and method include producing an HDD access request signal, initializing the TIC by resetting the TIC through a power-on of the TIC, performing an access of the HDD by driving the HDD after the initialization of the TIC is completed, and turning off an operation power of the TIC after the access of the HDD is completed.

Abstract: A data demodulation process rate is varied according to a reproduction state, thereby reducing power consumption while maintaining a reading performance in a favorable state. A channel rate process data demodulation device performs a data demodulation process by employing channel bit frequency. Further, a half rate process data demodulation device performs a data demodulation process by employing frequency half as high as the channel bit frequency. These devices demodulate digital data from an optical recording medium. A process rate switching device switches a process rate at data demodulation, whereby demodulation is performed by switching between the data demodulation devices according to a quality of a reproduction signal, so as to reproduce the digital data recorded on the optical recording medium.

Abstract: A method and system for measuring slider body clearance in a hard disk drive using positive and negative electrical pulses. In one embodiment, at least one positive direct current (DC) pulse is applied between a slider body and a hard disk of the hard disk drive. Furthermore, at least one negative direct current (DC) pulse is applied between the slider body and the hard disk. A contact potential voltage between said slider body and said hard disk is then determined in response to applying the at least one positive direct current (DC) pulse and the at least one negative direct current (DC) pulse.

Abstract: A method for simultaneously measuring contact potential and slider body clearance in a hard disk drive. In embodiments of the present invention, a plurality of direct current (DC) pulses are applied between a slider body and a hard disk of a magnetic disk drive. The contact potential voltage between the slider body and the hard disk is determined in response to applying the plurality of direct current (DC) pulses. The voltage of the plurality of direct current (DC) pulses is increased until a contact between the slider body and the hard disk is detected.

Abstract: A method and apparatus for tracking error detection in an optical disk reproduction system. The tracking error detecting apparatus generates a tracking error signal as a difference signal of optical detection signals generated by more than two optical detectors positioned along a diagonal line from a track center and includes binarizers which binarize each output of the optical detectors, phase locked loops (PLLs) which generate respective clock signals synchronized with the outputs of each of the binarizers, a phase difference detector which detects a phase difference between the synchronized signals output from the PLLs, and low-pass filters which filter the output of the phase difference detector to output the result as the tracking error signal. The tracking error detecting apparatus generates a tracking error signal which is not dependent on the lengths of pits or marks recorded on an optical disk, enhancing the reliability of the tracking error signal.

Abstract: A tilt sensor 23 is provided on a CD optical pickup 11, and a sub-chassis 24 and a height adjustment mechanism 25 and the like are provided for adjusting the tilt of a DVD optical pickup 12. A recording or reproduction position is read in by the DVD optical pickup 12 while moving the CD optical pickup 11 and the DVD optical pickup 12 along guide shafts 18 and 26 respectively, the amount of tilt of the optical disk 16 at this position is detected by the tilt sensor 23 of the CD optical pickup 11, the tilt of the laser light axis from the DVD optical pickup 12 is adjusted in accordance with the amount of tilt that is detected, and the amount of tilt of the optical disk 16 is corrected.

Abstract: A tracking controller includes a tracking error detecting section and a tracking control section. The tracking error detecting section generates and outputs a tracking error signal that represents how much the focal point of a light beam has shifted from a target track on a storage medium. The tracking control section generates a drive signal in response to the tracking error signal so as to move the light beam such that the focal point of the light beam is located right on the target track. The gain of at least one of the tracking error signal and the drive signal is switched depending on whether or not the focal point of the light beam is located on a recorded area of the storage medium on which data has already been written.

Abstract: In an optical pickup apparatus of the present invention, either a first laser diode emits a laser beam having a first wavelength or a second laser diode emits a laser beam having a second wavelength. An optical system focuses one of the two laser beams onto a recording surface of an optical recording medium. A photodetector unit receives reflection beams, which are reflected from the recording medium, to generate detection signals from the received reflection beams. A holographic unit has a first hologram suited to the first laser diode and a second hologram suited to the second laser diode, the first hologram provided to diffract a reflection beam of the laser beam of the first laser diode to the photodetector unit, and the second hologram provided to diffract a reflection beam of the laser beam of the second laser diode to the photodetector unit.

Abstract: A method is described for setting an optimum recording power level for recording information on an optical record carrier. First a series of test patterns is written on the record carrier with a different recording power. On reading the test patterns, the jitter values of each read signal is determined. The jitter as a function of recording power is approximated with two linear functions. The optimum recording power level for the record carrier is derived from intersection of the functions. The invention relates also to a device arranged to perform the method. The invention further relates to an optical record carrier comprising the optimum recording power as determined by the method according to the invention.

Abstract: This invention relates to a reproduced signal evaluation method of evaluating a reproduced signal reproduced from an information recording medium in which information composed of a plurality of codes differing in length is recorded and evaluates the reproduced signal on the basis of the reproduced signal of the next shortest code after the shortest code reproduced from the information recording medium.

Abstract: A method and an apparatus which controls write power of an optical driver by optimizing the number of channels used to drive a laser diode in a write mode while stabilizing the level of a write power voltage at an early stage of the write mode. The method of controlling the write power includes checking whether the write power provided to the laser diode included in the optical driver is stable, controlling the write power by increasing the number of channels used to control the write power so as to provide sufficient write power to drive the laser diode in response to the write power provided to the laser diode being unstable, and controlling the write power by using less channels than the channels used in response to the write power being unstable in response to the write power provided to the laser diode being stable. Accordingly, it is possible to reduce the size of a firmware by preventing channels unnecessary to perform a write mode from being used.

Abstract: The depth of pits is determined by a trade-off between the level of a push-pull signal used for servo application by a push-pull method and the level of an RF signal as a reproduced signal of information. The depth d is set to be the optimum for a disk system, which has a refractive index n of a medium, an optical wavelength ?, and an optical system with a NA (Numerical Aperture) of 0.75. The most suitable depth d for both the push-pull signal level and the RF signal level falls within a range of ?/5.5n?d??/4.7n, the second most suitable depth d falls with a range of ?/5.5n?d??/4.5n, and the depth d as the widest standard falls within a range of ?/8n?d??/4.5n.

Abstract: An actuator of an optical disk system and an apparatus producing a signal for driving the actuator, the actuator including a light source, with which information is recorded on or reproduced from an optical disk surface. In the actuator, an inner focusing coil and an outer focusing coil are installed near an inner boundary and an outer boundary, respectively, of the optical disk surface. A first signal wire is connected to a first port of the inner focusing coil and transmits an inner coil signal. A second signal wire is connected to a first port of the outer focusing coil and transmits an outer coil signal. A common signal wire is connected to a second port of the inner focusing coil and a second port of the outer focusing coil and transmits a common reference signal. Thus, a simple, inexpensive 8-wire actuator can be obtained.

Abstract: A system and method of identifying programs contained on a disk of any format, including, for example, either a single-sided or a double-sided disk with either a single-layer or multi-layer tracks, are presented. In particular, a dual-sided recording medium is disclosed having respective program data on the first and the second sides of said medium. In addition, the medium has a first area on the first side and a second area on the second side, and the areas have laser encoded data representing individualized information relating to said respective program data. The areas may or may not overlap each other depending on the configuration chosen. Also disclosed is an apparatus for laser encoding the above-described recording medium, and a method for processing a disk having more than one laser encoded areas.

Abstract: A laser power control apparatus for controlling the output power of a semiconductor laser used to record and reproduce data in and from a recording medium is provided. The laser power control apparatus includes a controller configured to vary the peak output power level of the semiconductor laser in a stepwise manner, calculate a differential efficiency at each of the varied peak output power levels, and determine a laser driving current based on a relation between the differential efficiency and the peak output power level. In addition, a laser driving unit is configured to drive the semiconductor laser using the laser driving current determined by the controller.