Abstract: A user evaluation apparatus includes a parameter determination module which determines parameters of a user evaluation model required to calculate a degree of usage influence so as to maximize a target function. The target function may be defined using weight values, measurement data, and a failure information counting result. The apparatus also includes a user evaluation module which calculates and displays the degree of usage influence using the measurement data and the parameters of the user evaluation model.

Abstract: A first module calculates a failure occurrence risk index of each data storage area address. A second module calculates a power saving index of each data storage area address. A third module calculates an access speed index per unit data volume necessary to access each data storage area address. A fourth module generates a distribution table that represents the failure occurrence risk index, the power saving index, and the access speed index for each candidate address, with respect to data to be distributed. A fifth module selects a candidate address in the distribution table such that the power saving index and the access speed index meet restricting conditions and the failure occurrence risk index is minimized, and distributes the data to the candidate address.

Abstract: An information reproduction method according to an aspect of this invention is directed to an information reproduction method which reproduces information from an information storage medium on which land and groove tracks which can record information are alternately formed in the radial direction along wobbles that represent address information, comprising determining a track structure of a current position traced by a light beam on the basis of the address information, and a track structure of a target position on the basis of a target position address, controlling access to the address of the target position by switching between a first servo polarity corresponding to a land track and a second servo polarity corresponding to a groove track at a predetermined timing as needed on the basis of the determination result of the two track structures, and reproducing predetermined information from the target position address.

Abstract: An optical disk apparatus includes an objective lens that condenses light on an information recording layer of an optical disk that has a first area with a first track pitch and a second area with a second track pitch, to form an optical spot. The apparatus also includes a tilt driver that inclines the objective lens; a positioning unit that positions the optical spot on a target track; a position error detector that detects a position error of the optical spot from the target track; a tilt detection correcting unit that calculates a tilt error signal based on a first position error detected when the optical spot is positioned on a target track in the first area and a second position error detected when the optical spot is positioned on a target track in the second area; and a tilt controller that controls an inclination based on the tilt error signal.

Abstract: An optical disk apparatus including a waiting position determining circuit which detects physical properties of each region in an optical disk after recording or reproducing processing is finished and decides a waiting position of an optical head according to the detection, and various kinds of control mechanisms which controls a position of the optical head according to the decided waiting position in order to move the optical head, is provided. By making the optical head wait at a position before two or more tracks in an unrecorded region, the recording processing can be resumed stably and surely and the recording processing can be preferentially performed in the remaining unrecorded region.

Abstract: A magnetic recording medium includes a discrete area and an offset amount measurement area. The discrete area has a plurality of magnetic tracks where data can be recorded and that has a non-magnetic track where the data cannot be recorded located between the plurality of adjacent magnetic tracks. In the offset amount measurement area, measurement data for measuring an offset amount indicating a relative distance from a center position of the magnetic track to the first head in a direction crossing the magnetic track when the second head is on the center position of the magnetic track can be recorded.

Abstract: An optical disk device has a recording information management portion which detects a distribution of a recorded region R and an unrecorded region M based on reflection light received by an optical head and an access target setting circuit which determines an access target of an optical head so as to make access to a target position of a recording layer of an optical disk while avoiding the unrecorded region M based on the detected distribution of the regions. Since an access is made while passing through only the recorded region R, a servo operation can be stabilized.

Abstract: An optical disk device comprises position control portions which carry out position control of at least one of an optical head and an objective lens based on a detection signal from the optical head, and disturbance learning portions which reduce a compensation gain of the position control portion in a range in which servo control is not deviated, and detect disturbance information of the optical disk to store it as learning disturbance information. Fine disturbance information can be reliably learned because the information is not affected by the compensation gain.

Abstract: A magnetic recording medium includes a discrete area and an offset amount measurement area. The discrete area has a plurality of magnetic tracks where data can be recorded and that has a non-magnetic track where the data cannot be recorded located between the plurality of adjacent magnetic tracks. In the offset amount measurement area, measurement data for measuring an offset amount indicating a relative distance from a center position of the magnetic track to the first head in a direction crossing the magnetic track when the second head is on the center position of the magnetic track can be recorded.

Abstract: There is provided a control circuit for arithmetically processing at least one of focus-directional and tracking-directional position error signals, and adding the arithmetic operation result as an input amount to a coil for driving in the opposite direction. The control circuit produces such a control signal as to cancel the effect of an oscillation mode of an objective lens holder. An output determination circuit temporarily restricts functions of the control circuit when the determination circuit has determined that a disturbance component is mixed in the position error signal. Thereby, even in the case of slight displacement, the objective lens can be controlled independently in the focusing and tracking directions while avoiding interference movement in both directions.

Abstract: A magnetic recording medium includes a discrete area and an offset amount measurement area. The discrete area has a plurality of magnetic tracks where data can be recorded and that has a non-magnetic track where the data cannot be recorded located between the plurality of adjacent magnetic tracks. In the offset amount measurement area, measurement data for measuring an offset amount indicating a relative distance from a center position of the magnetic track to the first head in a direction crossing the magnetic track when the second head is on the center position of the magnetic track can be recorded.

Abstract: An optical disk apparatus has a first optical system having an objective lens with a first NA, a second optical system having an objective lens with a second NA lower than the first NA, an addition mechanism for adding focus error signals detected by the first and second optical systems, and an alignment mechanism for aligning the objective lens in accordance with the addition result of the addition mechanism.

Abstract: An optical disk apparatus includes an objective lens that condenses light on an information recording layer of an optical disk that has a first area with a first track pitch and a second area with a second track pitch, to form an optical spot. The apparatus also includes a tilt driver that inclines the objective lens; a positioning unit that positions the optical spot on a target track; a position error detector that detects a position error of the optical spot from the target track; a tilt detection correcting unit that calculates a tilt error signal based on a first position error detected when the optical spot is positioned on a target track in the first area and a second position error detected when the optical spot is positioned on a target track in the second area; and a tilt controller that controls an inclination based on the tilt error signal.

Abstract: Electroconductive paste includes electroconductive powder of Ni, Cu or the like, a first binder resin such as ethyl cellulose resin or the like, a fatty acid which is solid at ordinary temperature (20 to 25° C.), and solvents. The solvents include a cyclic compound type solvent capable of dissolving the first binder resin, an aliphatic hydrocarbon type solvent incapable of dissolving a second binder resin such as butyral resin or the like contained in a ceramic green sheet, and an aromatic hydrocarbon type solvent incapable of dissolving the second binder resin.

Abstract: An optical disk device of the invention comprises a pickup which obtains a reading signal by irradiating an optical disk having plural recording layers with laser beam, a generating unit which generates a focus error signal from the reading signal, a control unit which focuses the laser beam based on the focus error signal, a holding unit which holds changes in a focus drive signal for driving the objective lens in a focus direction and the focus error signal as history information, and a determining section which determines where the focus position exists within the plural recording layers of the optical disk based on the focus error signal, the focus drive signal and the history information.

Abstract: There is provided a photodetector which has the function of measuring the intensity distribution of light with a simple and inexpensive construction and which has a selectivity for a measured wavelength band. The photodetector comprises a transparent semiconductor electrode part and counter electrode part on each of which a sensitizing dye is applied, and a buffer layer sandwiched therebetween, the counter electrode part or the transparent semiconductor electrode part being divided into a plurality of electrode cells. Thus, it is possible to realize a compact photodetector which carries out a photoelectric transfer using part of light in a wavelength band absorbed into the sensitizing dye and which has a wavelength selectively.

Abstract: Before tracking control, tilt control is performed using an offset value of a differential phase tracking error signal obtained by performing signal process of the outputs from, e.g., a 4-split photodetector. A direction in which the tilting angle of the tilt control is to be corrected is determined based on information indicating whether the center value of the differential phase tracking error signal is “offset to plus or minus”. Hence, tilt servo that aims at an optimal point is made while observing the amplitude of the differential phase tracking error signal using this offset polarity information.

Abstract: An information reproduction method according to an aspect of this invention is directed to an information reproduction method which reproduces information from an information storage medium on which land and groove tracks which can record information are alternately formed in the radial direction along wobbles that represent address information, comprising determining a track structure of a current position traced by a light beam on the basis of the address information, and a track structure of a target position on the basis of a target position address, controlling access to the address of the target position by switching between a first servo polarity corresponding to a land track and a second servo polarity corresponding to a groove track at a predetermined timing as needed on the basis of the determination result of the two track structures, and reproducing predetermined information from the target position address.

Abstract: A first reading signal to a fourth reading signal are acquired with a four division element from an optical disk. The first reading signal and a third reading signal are sampled and added at a predetermined timing to obtain a first addition signal, while the second reading signal and the fourth reading signal are sampled and added at a predetermined to obtain a second addition signal. A phase difference signal of the first addition signal and the second addition signal are detected by repeating comparison of the two signals until the same value is attained by differing sampling timing with respect to the first addition signal and the second addition signal when the same value is not attained in the first addition signal and the second addition signal in the comparison with the result that the tracking control is conducted based on the detected phase difference signal.

Abstract: A magnetic recording medium includes a discrete area and an offset amount measurement area. The discrete area has a plurality of magnetic tracks where data can be recorded and that has a non-magnetic track where the data cannot be recorded located between the plurality of adjacent magnetic tracks. In the offset amount measurement area, measurement data for measuring an offset amount indicating a relative distance from a center position of the magnetic track to the first head in a direction crossing the magnetic track when the second head is on the center position of the magnetic track can be recorded.