Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Keizo Miyata

Tatsuaki Ishida

Hideyuki Hashi

Taizou Hamada

Yasuaki Ban

Toshio Inaji

Hiroshi Kohso

Kiyokazu Tohma

Nobuyuki Komura

Hiroshi Ryonai

Toshio Makabe

Makoto Umeda

Taizo Hamada

Kiyokazu Toma

Toshiyuki Honda

Hiromi Kita

Yoshio Umeda

Masaya Sakaguchi

Masato Suto

Ryosuke Shimizu

Yoriko Takai

Terumi Yanagi

Kouji Taniguchi

Makoto Kimura

Syuichi Yoshida

A memory controller includes a reading/writing control unit for controlling writing and reading of data to and from a physical block of a nonvolatile memory, a writing mode table for storing one of a first writing mode of protecting data against a power shutdown during writing and a second writing mode of writing data at a higher speed than the first writing mode, and a setting unit for setting the writing mode received from an access device in a writing mode table. The reading/writing control unit performs data writing based on the writing mode that has been set in the writing mode table.

Nonvolatile storage device, access device and nonvolatile storage system

A cleaning method preventing foreign matter attached to a brush from being transferred back to a magnetic transfer carrier by removing foreign matter attached to a cleaning tool such as the brush with a dummy carrier having a recess equivalent to that on a surface of the magnetic transfer carrier.

Cleaning method for magnetic transfer carrier

A self-servo reference signal including a timing pattern and an oblique phase pattern is transferred in advance on a magnetic diskby magnetic printing. A phase difference detection sectiondetects a phase difference between the two patterns to detect the position of a magnetic head. A burst signal generated by a record signal generation sectionis recorded in a region of the magnetic diskwhere no self-servo reference signal is recorded. A track pitch calculation sectiondetermines a relationship between the reproduction output of the burst signal detected by a reproduction signal processing sectionand the phase difference detected by the phase difference detection section, thus calculating an optimum data track pitch.

Magnetic disk apparatus, method for determining data track pitch, and self-servo write method

A master information carrier capable of manufacturing a magnetic recording medium in which a preformat recording of information signals causing no reproduction signal detection errors arising from a pulse shift of a reproduction waveform is performed. A master information carrierhas an array of ferromagnetic thin filmsarranged according to the pattern of information signals and is used for forming magnetizationof a pattern corresponding to the array pattern of the ferromagnetic thin filmin a magnetic recording medium by applying a magnetic field while opposing the master information carrieragainst a magnetic recording medium. Each of the ferromagnetic thin filmsis formed such that each pattern length A becomes equal to a length including a correction amount &#x3b1; in addition to a length a between magnetic transition areasof the magnetizationto be formed in the magnetic recording medium

Master information carrier and method for manufacturing magnetic disc using the same

A head positioning apparatus capable of positioning a head at high speed and with high accuracy is provided. The head positioning apparatus includes a magnetic head, a head supporting mechanism, a coarse actuator, a fine actuator, a head position detection part, a fine movement control system for controlling the fine actuator based on the head position detected by the head position detection part, a head moving distance estimation part estimating the head moving distance representing the distance the magnetic head moves, and the coarse movement control system for controlling the coarse actuator based on the head moving distance estimated by the head moving distance estimation part.

Head positioning apparatus

A first estimatorestimates the position of a head based on a VCM driving signal uand a voltage signal Va output from a VCMto output a first head position estimation signal x. The first estimatorestimates the disturbance acting on a head supporting mechanismto output a disturbance estimation signal &#x3c4;. A second estimatorestimates the displacement of the head based on a control signal cfor a fine adjustment actuatorto output a displacement estimation signal x. The first head position estimation signal xand the displacement estimation signal xare added together to obtain a second head position estimation signal x. A position error signal e is generated using a head position signal x obtained by detecting the servo information and the second head position estimation signal x. A disturbance compensatorsynthesizes a VCM control signal cwith the disturbance estimation signal &#x3c4;to generate the VCM driving signal u.

Head positioning method, and disk apparatus using the same

A magnetic transfer method which superposes on a magnetic disk surface a magnetic transfer master disk () on which a magnetic film is formed so as to have an array pattern shape corresponding to a preset information signal, and magnetizes the magnetic film on the master disk () to thereby magnetic-transfer-record the array pattern of the information signal on the master disk () onto the magnetic disk as the magnetized pattern of the information signal, the method characterized by comprising a step of contacting/separating to/from a dummy disk () the magnetic film-formed surface of the master disk () to thereby clean the master disk (), and a step of superposing, after the cleaning, the master disk () on the magnetic disk for magnetic transfer recording; and a magnetic transfer device for the method.

Magnetic transfer method and magnetic transfer device

A disk apparatus includes: an actuator; a driver; a voltage detectorfor outputting first voltage signal Ed which is produced in a driving coilof the actuator; a voltage signal adjusterfor outputting pseudo disturbance signal ur and generating second voltage signal Edfrom pseudo disturbance signal ur, driving signal u, first voltage signal Ed, and disturbance estimation signal &#x3c4;d; a disturbance estimatorfor estimating the magnitude of disturbance load &#x3c4;d applied to a magnetic headfrom driving signal u and second voltage signal Edto output disturbance estimation signal &#x3c4;d; a position detectorfor generating position error signal e which corresponds to a current position of the magnetic head; a position controllerfor generating control signal c from position error signal e; and a correctorfor generating driving signal u from disturbance estimation signal &#x3c4;dand position control signal c.

Disk apparatus and head positioning method

A master information carrier includes a high-level region and a low-level region that are formed on a non-magnetic base. The high-level region includes a ferromagnetic thin film pattern that corresponds to preformat information signals. The master information carrier is brought into close contact with a magnetic disk by exhausting a gas from a hole of the magnetic disk to generate negative pressure in a space between the low-level region and the magnetic disk. In this case, to prevent deformation of the central portion of the master information carrier, an inner edge of the high-level region in the radial direction is extended to the vicinity of a hole edge of the magnetic disk so that a portion of the high-level region comes into contact with the vicinity of the hole edge. This configuration can improve the close contact between the master information carrier and the magnetic disk, thus achieving higher reliability of magnetic transfer recording.

Master information carrier and method for manufacturing magnetic disk

A position detector generates a position error signal corresponding to a current position of a head, a position controller generates a position control signal from the position error signal, a voltage detector detects a voltage signal generated when driving an actuator by a driver, a disturbance estimator generates a disturbance estimation signal from a driving signal and the voltage signal, and a corrector outputs the driving signal from the disturbance estimation signal and the position control signal. The disturbance estimator includes a comparator which compares the disturbance estimation signal with a voltage signal and which outputs a deviation signal, and an adder which adds a signal obtained by multiplying an integral signal, which is obtained by integrating the deviation signal, by a first coefficient and a signal obtained by multiplying a proportional signal proportional to the deviation signal by a second coefficient, and which generates the disturbance estimation signal. The disturbance estimation signal suppresses a tracking deviation of the head due to a disturbance such as an inertial force applied to the head actuator and stabilizes head positioning control.

Disk drive and disk drive control method

A disk storage apparatus includes: an actuator positioning a head with respect to a disk; a drive device driving the actuator; a voltage detection device detecting a voltage signal induced in driving the actuator; a disturbance estimation unit estimating the magnitude of load disturbance exerted on the head from a drive signal and the voltage signal, and outputting a disturbance estimation signal; a filter unit cutting off a high frequency component of the disturbance estimation signal, and outputting a filter signal; a position detection unit producing a position error signal corresponding to a current position of the head; a position control unit producing a position control signal based on the position error signal; and a correction unit outputting the drive signal based on the filter signal and the position control signal, and the apparatus controls stable positioning of the head against a resistance value fluctuation of a drive coil of the actuator and a resistance value change.

Disk storage apparatus and disk storage apparatus control method

A disturbance compensation signal is produced by estimating the magnitude of disturbance acting upon an actuator based on a driving signal and a voltage signal generated when driving the actuator. A control signal is produced by multiplying the disturbance compensation signal by a gain adjustment coefficient. A head position error signal is produced based on the target position of a magnetic head and the current position of the magnetic head that is detected based on servo information recorded in advance on a magnetic disk. A gain adjuster obtains the driving signal by adding together the control signal and a position control signal. The actuator is driven with the driving signal output from the gain adjuster.

A master disc capable of conducting a preformat recording by a magnetic transcription without causing any unevenness over an entire magnetic disc is provided. The master disc is provided with a radial land portion where an array of ferromagnetic thin films is formed and a concave portion against the land portion. The land portion and the concave portion are formed such that the land portion is joined with the surface of the magnetic disc when the present magnetic disc is overlapped on the magnetic disc, and that the concave portion is not contacted with the surface of the magnetic disc, and also that a space surrounded by the surface of the magnetic disc and the concave portion is open to air at a peripheral end portion of the magnetic disc.

Master disc and method for manufacturing magnetic disc using the same

The master information recording apparatus 100 includes a master information carrier, a master information carrier facing member, and a magnetic field applying member. A ferromagnetic thin film pattern formed on the surface of the master information carrier includes not less than two kinds of different patterns each having a different pattern angle showing an angle with respect to the direction of the relative movement between a magnetic head and a rotating magnetic recording medium. The magnetic field applying unit applies a magnetic field along the direction, which is perpendicular to the direction shown by an angle that is smaller than the pattern angle of the maximum pattern and larger than the minimum pattern angle of the pattern among the not less than two kinds of patterns.

Growing community of inventors

Osaka, Japan

Keizo Miyata