Hitachi Maxell, Limited

Hitachi, Ltd.

Hitaci Maxell, Ltd.

Nobuhiro Umebayashi

Teruhisa Miyata

Akira Miyake

Kazuya Fukunaga

Yoshito Tanaka

Kunio Mizushima

Kenji Tanaka

Norio Ohta

Mikio Kishimoto

Yoshitaka Kojima

Minoru Fujita

Akito Sakemoto

Shizuka Yamaguchi

Hiroshi Maruyama

Shoichi Nakashima

Hiroshi Obara

Hiroshi Ishihama

Yoshikazu Kai

Masahiro Kishigami

An imaging device includes a photoreceptor portion including a plurality of photoreceptors arranged in an array, a microlens array including a plurality of microlenses, and a light shielding layer placed between the photoreceptor portion and the microlens array. The light shielding layer has apertures located corresponding to the plurality of photoreceptors. An optical relationship of an actual length dof an aperture width of the apertures on a side of the photoreceptors, an actual length p of a distance between adjacent microlenses, an equivalent air length tof a distance between vein and a top of the microlenses, and an equivalent air length tof a thickness between the top of the microlenses and an aperture position of the apertures on the side of the photoreceptors satisfies: 

Imaging device and biometrics authentication apparatus

A magnetic recording medium wherein thickness of the magnetic layer is less than the wavelength of projected light onto the surface of the magnetic recording medium having a multiplicity of magnetic-head tracking recesses formed thereon at predetermined intervals, and data tracks for recording thereon predetermined information provided between every two adjacent magnetic-head tracking recesses, each tracking recess and data track having a function to track a magnetic head in accordance with reflected light from the magnetic-head tracking recesses, the data tracks being provided at a track density greater than 1000 TPI and light transmittance of the magnetic recording medium is less than 5%.

Magnetic recording medium

A magnetic disk has optical servo grooves formed at specified intervals along data tracks so that variations in reflected light of light applied to the grooves are detected so as to allow a magnetic head to perform tracking servo. A level difference between a regenerative signal and a fundamental wave of modulation noise during reads of data recorded on the data tracks (4A, 4B) is set to 28 dB or more. Thus, comb-shaped modulation in a regenerative signal due to optical servo grooves is reduced so that output drop of the regenerative signal is suppressed and deterioration of window margin and the like is lessened.

Magnetic disk which reduces deterioration in regenerated signals due to

There is provided a stamper for producing a recording medium exhibiting excellent durability and capable of stably forming projections and pits and a method of producing the stamper. A stamper for producing a recording medium comprising projections and pits in a predetermined pattern on the surface thereof, wherein a value of tan .theta..sup.-1 obtainable from an enlargement angle .theta. of an output from a cartridge with respect to an enlargement of an output denoting a load measured by a test of scratching the surface having the projections and pits under conditions that a diameter of a stylus is 100 .mu.m and a loading speed of 1 .mu.m/second is 1.3 or more.

Stamper for producing recording medium

A magnetic disc cartridge comprising a cartridge case, a magnetic disc housed rotatably in the cartridge case, and a liner, which serves as a cleaning sheet, secured on the inner surface of the cartridge case, characterized in that the magnetic disc has a magnetic layer containing a ferromagnetic metal powder, a reinforcing powder, whose content is defined in the range of from 5 to 40% by weight, and a fatty acid ester with a melting point of 0.degree. C. or lower, and that at least the disc side surface layer of the cleaning sheet, which is brought into sliding contact directly with the magnetic layer, is almost entirely composed of rayon fiber, such that the magnetic disc cartridge of the present invention can provide a highly reliable magnetic disc cartridge having a magnetic disc which is excellent in durability and substantially error free.

Magnetic disc cartridge including a magnetic disc having a cleaning

There is provided a magnetic recording medium which is highly reliable so that tracking servo can be properly effected wherein Z.ltoreq.0.49 is established when light reflectance on a data track is represented by X, light reflectance of a magnetic head-tracking recess is represented by Y, and Z=Y/X.

A magnetic recording medium in which the center of a magnetic head can be brought to a centerline of a reference track, thereby enhancing the reliability of the magnetic recording medium, the reference track being provided at a predetermined position of a magnetic layer of the medium, a number of magnetic head-tracking optical tracks are provided respectively at positions spaced predetermined distances from the reference track in a direction perpendicular to the direction of travel of the magnetic head, and a data track is formed between any two adjacent ones of the magnetic head-tracking optical tracks, the reference track having a pair of reference recess regions arranged symmetrically with respect to an arbitrary point on the centerline of the reference track, and a flat portion with no recess formed adjacent to each of the reference recess regions, the recess in each reference recess region being formed by cutting by a laser.

Magnetic recording medium having a reference track structure for

A magnetic recording/reproducing apparatus and method, the apparatus including a drive mechanism for driving a flexible magnetic disk loaded thereon to rotate, the magnetic disk being comprised of a transparent and flexible base film formed with first and second magnetic layers on both sides thereof, each of the magnetic layers having a film thickness of no greater than 1 .mu.m, surface of the first magnetic layer being flat, the outer surface of the second magnetic layer on the side away from the first magnetic layer, being provided with recesses for tracking servocontrol extending in the direction of rotation of the magnetic disk; a light emitting element for tracking servocontrol arranged on the side of the magnetic disk facing the first magnetic layer; and a light receiving element for receiving a light beam for tracking servocontrol, the light beam having passed through at least the first magnetic layer, the base film and the second magnetic layer after being emitted from the light emitting element, whereby using the light that has passed through the magnetic disk, proper tracking servocontrol is realized with high reliability, while improving an overwrite characteristic and undergoing less noise.

Recording/reproducing system using a flexible magnetic disk

A magnetic head supporting device for supporting at least one magnetic head in contact with a flexible magnetic disk so as to record and reproduce signals in and from the flexible magnetic disk. The magnetic head supporting device comprises a gimbal spring having a central portion to which the magnetic head is secured at one side thereof; and a pivot which contacts on the opposite side of the central portion of the gimbal spring so as to support the center of the magnetic head through the intermediary of the gimbal spring. The gimbal spring includes an intermediate frame portion which supports the central portion in such a manner as to impart thereto a degree of freedom of rotation in the circumferential direction or in the radial direction of the magnetic disk, and an outer holding portion which supports the intermediate frame portion in such a manner as to impart thereto a degree of freedom of rotation in the direction perpendicular to the direction of freedom of rotation imparted by the intermeidate frame portion to the central portion. The width of parts of the intermediate frame portions extending in parallel to the direction of running of the surface of the magnetic disk, as measured in the direction perpendicular to the running direction, is determined to be smaller in the upstream portion of the intermediate frame portion than in the downstream portion of the same as viewed in the direction of running of the surfacae of the magnetic disk.

Magnetic head supporting device

A magnetic head device with head cores connected to end surfaces of sliders, opposing each other on both sides of a magnetic disc, wherein one head core and slider combination is mounted on a gimbal spring, and a pivot member for pressing the magnetic disc, the pivot having plural pressing members aligned in the radial direction of the magnetic disc, the pivot being formed so that the pressing force can be applied generally uniformly to every part of the upper core and lower core.

Magnetic head device for improving head placement on a magnetic disc

In a recording disc cartridge having a recording disc rotatably supported by a hub assembly in a disc case, the hub assembly is formed by a hub body and a reinforcing metal plate laid on one of the surfaces of the hub body so as to prevent thermal deformation of the recording disc due to deformation of the hub body.

Growing community of inventors

Tsukuba, Japan

Nobuhiro Umebayashi