Patents by Inventor Masatoshi Sakurai

Masatoshi Sakurai has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • MAGNETIC RECORDING MEDIUM AND METHOD OF MANUFACTURING THE SAME
    Publication number: 20090317662
    Abstract: A magnetic recording medium has magnetic patterns formed of a patterned ferromagnetic layer, and a non-magnetic layer including a component of the ferromagnetic layer and separating the magnetic patterns, in which a thickness “a” of the non-magnetic layer and a thickness “b” of the magnetic patterns satisfy a relationship of: a<b.
    Type: Application
    Filed: August 26, 2009
    Publication date: December 24, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Yosuke Isowaki, Satoshi Shirotori, Yoshiyuki Kamata, Kaori Kimura, Masatoshi Sakurai
  • MAGNETIC RECORDING MEDIUM AND METHOD OF MANUFACTURING THE SAME
    Publication number: 20090317661
    Abstract: A magnetic recording medium has recording regions including patterns of a magnetic material corresponding to servo signals and recording tracks, non-recording regions including an oxide of the magnetic material formed between the recording regions, and surface oxide films including an oxide of the magnetic material formed on surfaces of the recording regions.
    Type: Application
    Filed: August 26, 2009
    Publication date: December 24, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventor: Masatoshi SAKURAI
  • Substrate for magnetic recording media, magnetic recording media and magnetic recording apparatus
    Patent number: 7635529
    Abstract: According to one embodiment, a substrate for a magnetic recording media has circumferential protrusions corresponding to recording tracks and circumferential recesses corresponding to grooves between the recording tracks, in which the substrate satisfying at least one of conditions of (a) a surface of the recess has a surface energy smaller than that of the protrusion, (b) the surface of the recess is modified with a thermally decomposable or deformable substance, (c) the surface of the recess has surface roughness smaller than that of the protrusion, (d) crystal orientation is more disturbed on the surface of the recess than on the protrusion, (e) the surface of the recess is modified with a substance that causes reaction with a magnetic material or that diffuses into the magnetic material, and (f) the surface of the recess is modified with a substance soluble in a solvent or with a deformable substance.
    Type: Grant
    Filed: June 28, 2006
    Date of Patent: December 22, 2009
    Assignees: Showa Denko K.K., Kabushiki Kaisha Toshiba
    Inventors: Katsuyuki Naito, Masatoshi Sakurai, Akira Kikitsu, Yoshiyuki Kamata, Naoko Kihara, Masahiro Oka
  • Recording media, recording and reproducing apparatus, and method for recording and reproducing
    Patent number: 7623311
    Abstract: A magnetic recording layer is formed on a surface of a substrate in magnetic recording media to define magnetic recording regions. Magnetic missing portions are provided in the magnetic recording regions, information cannot be magnetically recorded in the magnetic missing portions. The present invention provides magnetic recording media that enables authentication.
    Type: Grant
    Filed: March 15, 2006
    Date of Patent: November 24, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masatoshi Sakurai, Takeshi Okino
  • Method of forming patterns and method of manufacturing magnetic recording media
    Patent number: 7618549
    Abstract: According to one embodiment, a method of forming patterns is provided, in which the method including forming a resist on an underlying material, pressing a stamper having patterns of protrusions and recesses, sidewalls of which protrusions are tapered, onto the resist to form a patterned resist having patterns of protrusions and recesses, sidewalls of which protrusions are tapered, forming a protective film on the patterned resist, performing anisotropic etching to leave the protective film on the tapered sidewalls of protrusions of the patterned resist, etching a resist residue remaining in recesses of the patterned resist using the protective film as a mask, and etching the underlying material using the protective film and the patterned resist as a mask.
    Type: Grant
    Filed: October 16, 2006
    Date of Patent: November 17, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Satoshi Shirotori, Yoshiyuki Kamata, Masatoshi Sakurai, Akira Kikitsu
  • PATTERN TRANSFER METHOD
    Publication number: 20090277574
    Abstract: According to one embodiment, a pattern transfer method includes spin-coating one surface of a medium substrate with photopolymer having viscosity of 10 cps or less to form an photopolymer layer having a thickness of 200 nm or less, bonding the one surface of the medium substrate and the patterned surface of the first transparent stamper under vacuum with the photopolymer layer sandwiched therebetween, applying an ultraviolet ray to the photopolymer layer through the first transparent stamper to cure the photopolymer layer, and peeling off the first transparent stamper to form the photopolymer layer to which patterns of protrusions and recesses are transferred on the one surface of the medium substrate to control a thickness of the photopolymer layer remaining in recesses to 100 nm or less.
    Type: Application
    Filed: May 11, 2009
    Publication date: November 12, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Shinobu SUGIMURA, Seiji MORITA, Akiko YUZAWA, Masatoshi SAKURAI
  • STAMPER HOLDER, MOLDING DIE AND MOLDED SUBSTRATE FOR RECORDING MEDIUM
    Publication number: 20090280285
    Abstract: According to one embodiment, there is provided a stamper holder which holds a disk-shape metal stamper for molding having a center hole with an inner diameter of 17.5 mm or less and formed with patterns of protrusions and recesses for a recording medium on a surface in a state that the stamper holder is fixed to a first die having a center hole, in which the stamper holder has an approximately cylindrical shape so as to be inserted into the center hole of the first die and comprises a flange provided at one end configured to hold an inner peripheral portion of the stamper surface near the center hole, and an outer diameter of the flange is 17.6 mm or less.
    Type: Application
    Filed: May 8, 2009
    Publication date: November 12, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Shinobu Sugimura, Seiji Morita, Akiko Yuzawa, Masatoshi Sakurai
  • SUBSTRATE FOR MAGNETIC RECORDING MEDIUM, MAGNETIC RECORDING MEDIUM, AND MAGNETIC RECORDING AND REPRODUCING APPARATUS
    Publication number: 20090273858
    Abstract: It is possible to improve the recording and reproducing S/N ratio, the reproduction signal intensity, and the degree of high density recording. There are provided a plurality of recording tracks formed on a substrate, each recording track being formed of a magnetic material, and non-recording sections formed on the substrate, each non-recording section separating adjacent recording tracks, each recording track including a plurality of recording sections and connecting sections for connecting the recording sections adjacent thereto in a track longitudinal direction, and each connecting section having a cross-sectional area in a track width direction that is smaller than a cross-sectional area in a track width direction of adjacent recording sections.
    Type: Application
    Filed: July 15, 2009
    Publication date: November 5, 2009
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Kaori KIMURA, Masatoshi Sakurai, Akira Kikitsu, Yoshiyuki Kamata, Satoshi Shirotori, Hiroyuki Hieda
  • RESIN IMPRINT STAMPER AND METHOD OF MANUFACTURING THE SAME
    Publication number: 20090246310
    Abstract: According to one embodiment, a resin imprint stamper formed of a resin material in an annular shape having a through-hole in a central part thereof, including a pattern area formed on a part of a surface thereof in which a plurality of lands and grooves are circumferentially arranged with a track pitch of 100 nm or less, and the pattern height of at most 100 nm, wherein no protrusion and step having a height exceeding 10 ?m from a top surface of the pattern area are present in a region less than 3 mm from an end of the pattern area toward an inner periphery thereof.
    Type: Application
    Filed: March 27, 2009
    Publication date: October 1, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Masatoshi Sakurai, Seiji Morita, Shinobu Sugimura, Akiko Yuzawa
  • IMPRINTING METHOD AND STAMPER
    Publication number: 20090243152
    Abstract: According to one embodiment, an imprinting method includes applying a resist to a substrate, imprinting a stamper on which protruded patterns are formed against the resist applied to the substrate, forcing a distal end of a peeling wedge into a part between the substrate and the stamper, and introducing a gas between the substrate and the stamper to peel off the stamper from the substrate, in which a gap between the substrate and the stamper is made larger than a thickness of the resist at a part into which the distal end of the peeling wedge is forced.
    Type: Application
    Filed: March 27, 2009
    Publication date: October 1, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Akiko YUZAWA, Seiji MORITA, Shinobu SUGIMURA, Masatoshi SAKURAI
  • Method of Manufacturing Stamper, and Stamper
    Publication number: 20090232928
    Abstract: According to one embodiment, a method of manufacturing a stamper includes forming a conductive layer on a surface of a master having patterns of protrusions and recesses, forming an electroforming layer on the conductive layer, separating the electroforming layer and the conductive layer from the master to form a stamper to which the patterns of protrusions and recesses of the master are transferred, removing a resist left on the surface of the stamper, and etching the surface of the stamper with an acidic solution having a pH value of less than 3.
    Type: Application
    Filed: May 27, 2009
    Publication date: September 17, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Shinobu Sugimura, Kaori Kimura, Takuya Shimada, Yoshiyuki Kamata, Masatoshi Sakurai
  • Magnetic recording media, substrate for magnetic recording media, and magnetic recording apparatus
    Patent number: 7580223
    Abstract: According to one embodiment, a magnetic recording media includes a substrate having recording tracks and separating regions separating the recording tracks, the separating regions having patterns of protrusions and recesses formed therein, and a recording film deposited on the substrate, in which a difference in height between a top of the recording track and a top of the separating region is 2 nm or more and 7 nm or less, and a difference in height between the top of the recording track and a bottom of the separating region is 10 nm or more.
    Type: Grant
    Filed: June 28, 2006
    Date of Patent: August 25, 2009
    Assignees: Kabushiki Kaisha Toshiba, Showa Denko K.K.
    Inventors: Masatoshi Sakurai, Akira Kikitsu, Masahiro Oka
  • Method for manufacturing a magnetic recording medium utilizing first and second imprint stampers
    Patent number: 7575705
    Abstract: An imprint stamper for manufacturing a recording medium includes a first transfer region which corresponds to a servo region of a recording medium using a sector servo system and has a pattern with a plurality of quadrilateral recess or protrusion portions formed in a surface thereof, and a second transfer region which corresponds to a data region of the recording medium and has a pattern with a plurality of dots of recess or protrusion portions arrayed in a form of a hexagonal lattice in a surface thereof.
    Type: Grant
    Filed: March 27, 2007
    Date of Patent: August 18, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masatoshi Sakurai, Yoshiyuki Kamata
  • MAGNETIC RECORDING MEDIUM AND METHOD OF MANUFACTURING THE SAME
    Publication number: 20090202865
    Abstract: According to one embodiment, a magnetic recording medium includes magnetic patterns made of a ferromagnetic recording layer containing Co, and a nonmagnetic layer which separates the magnetic patterns and has a lower Co concentration than the magnetic patterns.
    Type: Application
    Filed: April 28, 2009
    Publication date: August 13, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kaori Kimura, Yoshiyuki Kamata, Satoshi Shirotori, Masatoshi Sakurai
  • Magnetic recording medium, method of manufacturing the same, and magnetic recording/reproduction apparatus
    Patent number: 7572528
    Abstract: A magnetic recording medium is obtained by easily patterning a magnetic recording layer without deteriorating its electromagnetic conversion characteristics, by forming a silicon-based protective film between the magnetic recording layer and a photoresist, and performing dry etching and oxygen plasma processing.
    Type: Grant
    Filed: May 24, 2005
    Date of Patent: August 11, 2009
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Takayuki Yamamoto, Masatoshi Sakurai, Yoshiyuki Kamata
  • METHOD OF MANUFACTURING DISCRETE TRACK RECORDING MEDIUM AND DISCRETE TRACK RECORDING MEDIUM
    Publication number: 20090195929
    Abstract: According to one embodiment, a method of manufacturing a discrete track recording medium includes forming protruded magnetic patterns on a substrate, and repeating processes of depositing a nonmagnetic material so as to be filled in recesses between the magnetic patterns and etching back the nonmagnetic material two or more times with rotating the substrate in a plane thereof by an angle less than one revolution.
    Type: Application
    Filed: March 9, 2009
    Publication date: August 6, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Yoshiyuki Kamata, Satoshi Shirotori, Kaori Kimura, Masatoshi Sakurai
  • METHOD OF MANUFACTURING MAGNETIC RECORDING MEDIUM
    Publication number: 20090166323
    Abstract: According to one embodiment, a method of manufacturing a magnetic recording medium includes depositing a magnetic recording layer and a sacrifice layer on a substrate, patterning the sacrifice layer and magnetic recording layer to form protruded magnetic patterns and sacrifice patterns, depositing a nonmagnetic material in recesses between the magnetic patterns and sacrifice patterns and on the sacrifice patterns, and etching back the nonmagnetic material.
    Type: Application
    Filed: March 9, 2009
    Publication date: July 2, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Satoshi Shirotori, Yoshiyuki Kamata, Kaori Kimura, Masatoshi Sakurai
  • DISK DRIVE HAVING A DISK OF DISCRETE-TRACK MEDIA TYPE
    Publication number: 20090168228
    Abstract: According to one embodiment, a disk drive has a DTM type disk. The DTM type disk has a servo area on one recording surface. In the servo area, a servo pattern is recorded. The servo pattern is composed of a projection-depression pattern and an N- and P-pole magnetic pattern. The N- and P-pole magnetic pattern is recorded in an address-data region that contains a cylinder code.
    Type: Application
    Filed: December 18, 2008
    Publication date: July 2, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Hideo Sado, Masatoshi Sakurai, Yuji Sakai
  • METHOD OF MANUFACTURING MAGNETIC RECORDING MEDIUM AND MAGNETIC RECORDING MEDIUM
    Publication number: 20090162704
    Abstract: According to one embodiment, a method of manufacturing a magnetic recording medium includes forming protruded magnetic patterns on a substrate, depositing a nonmagnetic material in recesses between the magnetic patterns and on the magnetic patterns, and etching back the nonmagnetic material using an oxygen-containing etching gas while reforming a surface of the nonmagnetic material.
    Type: Application
    Filed: March 9, 2009
    Publication date: June 25, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kaori Kimura, Yoshiyuki Kamata, Satoshi Shirotori, Masatoshi Sakurai
  • MAGNETIC RECORDING MEDIUM, METHOD OF MANUFACTURING THE SAME, AND MAGNETIC RECORDING APPARATUS
    Publication number: 20090161257
    Abstract: According to one embodiment, a magnetic recording medium includes protruded magnetic patterns formed on a substrate, and a non-magnetic material filled in recesses between the magnetic patterns and made of a multi-element amorphous alloy containing Ni or Cu, and two or more metals selected from the group consisting of Ta, Nb, Ti, Zr, Hf, Cr, Mo and Ag.
    Type: Application
    Filed: March 9, 2009
    Publication date: June 25, 2009
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Akiko Yuzawa, Masatoshi Sakurai, Yoshiyuki Kamata, Satoshi Shirotori, Kaori Kimura, Tsuyoshi Onitsuka