Hitachi, Ltd.

Nihon Micro Coating Co., Ltd.

Hitachi Metals, Ltd.

Hitachi Maxell, Limited

Research Development Corporation of Japan

Noriyuki Kumasaka

Shigekazu Otomo

Takeo Yamashita

Mitsuhiro Kudo

Noritoshi Saito

Hideo Fujiwara

Yoshihiro Shiroishi

Kazuo Shiiki

Yuji Horie

Toshio Kobayashi

Ryoichi Nakatani

Katsutoshi Nii

Kiminari Shinagawa

Takashi Kouno

Takeshi Kimura

Yoshihiro Hamakawa

Hideo Zama

Kenkichi Inada

Takashi Naito

Hiroki Yamamoto

Hisanobu Kanamaru

Yutaka Sugita

Kouki Uefune

Ken Takahashi

Hiroshi Nishida

Mitsuru Saito

Fumiyoshi Kirino

Takashi Namekawa

Masaru Muranishi

Ryo Imura

Shinji Takayama

Kenji Tomida

Kazuhiko Kawakami

Yuuichi Yanagase

Juichi Morikawa

Nagatugu Koiso

Teizo Tamura

Kazuei Yamaguchi

Takeshi Miura

Sanaki Horimoto

Ryo Suzuki

Hitoaki Owashi

Takaharu Noguchi

Hitoshi Nakamura

Nobutaka Amada

Yoshiaki Yamauchi

Takeshi Tottori

Osamu Inagoya

Nobuyuki Sugishita

Takuya Nagamine

Nobuo Kobayashi

Takehiro Watanabe

Masashi Hayashi

Souzou Sasajima

Fumi Murokawa

Masahiro Hosoi

Hiroyuki Suzuki

Hisashi Takano

Jun Tamura

Kiyoshi Ogata

Yoshibumi Matsuda

Yasuhiro Yoshimura

Yoshio Homma

Yoshishige Endo

Kazumasa Takagi

Isamu Yuito

Ikuo Nishida

Masaki Ohura

Kyuichiro Nagai

Yoshinobu Tarutani

Eijin Moriwaki

Shinobu Yoshida

Kuninori Imai

Akihiro Sakamoto

Sadao Hishiyama

Norikazu Tsumita

Tomoyuki Ohno

Takuo Tamura

Hisahiro Miki

Tsutomu Iimura

Toshikazu Nishiyama

Asao Nakano

Atsushi Saiki

Kazufumi Suenaga

Kazuto Oyama

Nobuyuki Yamada

Mitsuo Abe

Takayuki Kobayashi

Tomoki Hirata

Minoru Yamano

Hiroshi Tomishima

Takeshi Tajima

Yasuaki Horiuchi

Tatsuya Tanifuji

Yoshihiro Satou

Masahiko Fujishiro

Isamu Yuitoo

Teizou Tamura

Yasuyuki Yokota

Sigeo Imai

A glass substrate for perpendicular magnetic recording, having a surface with an average surface roughness of 2.0&#x212b; or less and surface height variations of 1&#x212b; or less with wavelengths in the range of 0.05 mm-0.5 mm in both radial and circumferential directions, is produced by rotating a glass substrate, supplying polishing slurry containing a specified amount of abrading particles of artificial diamond on its surface, pressing a polishing tape on the surface and causing this polishing tape to travel in a direction opposite to the direction of rotation of the glass substrate.

Method of producing glass substrate for perpendicular magnetic recording disk

An oxide superconductor member is composed of a tape-shaped substrate, an intermediate layer formed on this substrate and an oxide superconductor thin film layer formed on this intermediate layer. A surface of the tape-shaped substrate is polished by continuously running the tape-shaped substrate. The polishing step includes initial polishing process and finishing process which are carried out such that the average surface roughness Ra of the substrate becomes 2 nanometers or less and the in-plane directionality of the intermediate layer becomes 5&#xb0; or less after the polishing step.

Method for polishing tape-shaped substrate for oxide superconductor, oxide superconductor, and base material for oxide superconductor

A cleaning tape has a base tape made of a synthetic resin and a cleaning layer formed on a surface of this base tape. The cleaning layer has a binding agent and a large number of spherical particles dispersed in the binding agent in a single particle layer. Such a cleaning tape is capable of removing very small unwanted protrusions and particles on the surface of a target object such as a magnetic hard disk without forming scratches.

Cleaning tape and method of producing same

Diamond clusters are used as a polishing material of free abrading particles, each being a combination of artificial diamond particles having primary particle diameters of 20 nm or less and impurities that are attached around these diamond particles. The density of non-diamond carbon contained in the impurities is in the range of 95% or more and 99% or less, and the density of chlorine contained in other than non-diamond carbon in the impurities is 0.5% or more and preferably 3.5% or less. The diameters of these diamond clusters are in the range of 30 nm or more and 500 nm or less, and their average diameter is in the range of 30 nm or more and 200 nm or less. Such polishing material is produced first by an explosion shock method to obtain diamond clusters and then removing the impurities such that density of non-diamond carbon contained in the impurities and density of chlorine contained in other than non-diamond carbon in the impurities become adjusted.

Method of producing polishing material comprising diamond clusters

A target surface of a tape-shaped substrate of an oxide superconductor with an intermediate layer formed on this target surface and an oxide superconductor thin film is polished by causing the tape-shaped substrate to continuously run. The polishing step includes an initial polishing process for carrying out random polishing of the target surface and a finishing process that is carried out after the initial polishing process for forming grooves on the target surface along the running direction of the substrate. The intermediate layer has an in-plane directionality of 7&#xb0; or less. The tape-shaped substrate is fabricated by rolling nickel, a nickel alloys or stainless steel.

Method of polishing tape-shaped substrate and substrate for oxide superconductor

Diamond clusters are used as a polishing material of free abrading particles, each being a combination of artificial diamond particles having primary particle diameters of 20 nm or less and impurities that are attached around these diamond particles. The density of non-diamond carbon contained in the impurities is in the range of 95% or more and 99% or less, and the density of chlorine contained in other than non-diamond carbon in the impurities is 0.5% or more and preferably 3.5% or less. The diameters of these diamond clusters are in the range of 30 nm or more and 500 nm or less, and their average diameter is in the range of 30 nm or more and 200 nm or less.

Polishing material comprising diamond clusters

Texturing slurry for texturing a substrate for a magnetic hard disk is obtained by dispersing abrading particles of a specified kind in a specified kind of dispersant. The abrading particles include diamond clusters formed with artificial diamond particles with primary particle diameter of 20 nm or less and surrounded by impurities containing chlorine at a certain ratio. The cluster diameter and the average cluster diameter of the diamond clusters are each within a specified range. For texturing a substrate surface, the substrate is rotated, texturing slurry of this invention is supplied to the surface and a texturing tape of a specified kind is pressed against the substrate surface while it is caused to run.

Texturing slurry and texturing method by using same

Provided are a glass such as a sealing glass which contains a rare earth element and crystalline particles, a structure made by sealing with said sealing glass, a magnetic head made by bonding using said sealing glass, and a magnetic recording and reproducing apparatus on which said magnetic heads are mounted. According to the glass of the present invention, magnetic heads, and other structures can be bonded at low temperatures and a high bond strength can be attained, and thus, magnetic heads having high-speed sliding properties and magnetic recording and reproducing apparatuses of high reliability can be obtained. The glass can be also used for heat resistant parts such as a pannel glass for a cathode-ray tube and the like.

Magnetic head with sealing glass composition

Glass composition, structure, and apparatus using the same

A disk drive is realized, which omits running-in for stabilizing a change in a correcting function produced by sliding between balls and a rolling groove in an unbalance correcting mechanism, and prevents immobility and straying of balls, and which comprises a unit mechanism assembled by using 12 balls subjected to surface treatment with heptadecafluorodecyltrimethoxysilane and a turntable plated with a chemical nickel plating containing phosphorus and boron to have a thickness of 5 &mgr;m and by injecting 1 microliter of ester oil into the rolling groove, and further comprises a recess formed in a sidewall of the rolling groove of the unbalance correcting mechanism to prolong the service life of the correcting function.

Disk drive with unbalance correcting mechanism

A disk drive unit includes a rotary member, which has a spindle, and has an information-recording disk fixedly mounted thereon, and a bearing unit rotatably supporting the spindle. The bearing unit includes a radial bearing device, provided in opposed relation to an outer peripheral surface of the spindle, and a thrust bearing device provided in opposed relation to a distal end surface of the spindle. The radial bearing device has a concentric arc-shaped bearing surface, which is concentric with the circular outer periphery of the spindle, and a non-concentric arc-shaped bearing surface which is non-concentric with the circular outer periphery of the spindle. The disk drive unit further includes a motor for imparting a rotational force to the spindle, and a lubricating fluid filled in the bearing unit.

Disk drive unit with hydrodynamic fluid bearing unit and disk device with said drive unit

An apparatus for recording and reproducing a digital video signal on and from a common recording medium by using the head configuration common to the conventional one while maintaining exchangeability with the current analog VTR. An analog video and audio signals are recorded and reproduced on and from an video track and an underlying deep-layer track, respectively, by means of magnetic heads and magnetic heads. On the other hand, a digital video and audio signal is recorded and reproduced on and from two adjacent tracks by means of the magnetic heads for analog audio recording. During reproduction, an identification signal generating circuit generates an identification signal for discriminating a recorded signal, and a control signal is PWM modulated with the identification signal and recorded on a control track by means of a magnetic head.

Video signal recording and reproducing apparatus compatible with analog and digital video signal recording and reproducing

The present invention provides a disk apparatus and a motor therefor that require low power consumption and reduce errors during recording or reproduction by damping vibration, preventing the motor from falling toward a head. In a disk apparatus comprising a motor and a head, the motor has a rotating portion and a fixed portion, the rotating portion of the motor has a device for holding a disk, the fixed portion of the motor has a bearing section and a stator section mounted in the disk apparatus via damping members, and the damping members are provided in such a way that one side of these members which is closer to a line joining the motor with the head has a higher rigidity than the other side.

Disk apparatus and motor therefor

Growing community of inventors

Ome, Japan

Noriyuki Kumasaka