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).

  • Publication number: 20120060073
    Abstract: According to one embodiment, there is provided a magnetic recording apparatus configured to record data subjected to error correcting coding according to a shingled recording scheme, the magnetic recording apparatus including a magnetic recording medium in which unit bits of the data subjected to error correcting coding are recorded with phase shifted between adjacent tracks, a read head having a width covering a plurality of tracks and configured to read data from the plurality of tracks, and a recording controller configured to record the data subjected to error correcting coding and a parity for the data in the plurality of tracks covered by the read head, in a divided manner.
    Type: Application
    Filed: August 12, 2011
    Publication date: March 8, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Akihiro ITAKURA, Masatoshi Sakurai
  • Publication number: 20120052328
    Abstract: According to one embodiment, a method of manufacturing a patterned medium includes forming an implantation depth-adjusting layer above a magnetic recording layer, the magnetic recording layer being made of a material that is deactivated when implanted with a chemical species, and the implantation depth-adjusting layer being made of a material that is etched when irradiated with an ion beam of the chemical species and irradiating the implantation depth-adjusting layer with the ion beam to implant the chemical species into a part of the magnetic recording layer through the implantation depth-adjusting layer while etching the implantation depth-adjusting layer by an action of the ion beam to decrease a thickness of the implantation depth-adjusting laver.
    Type: Application
    Filed: June 22, 2011
    Publication date: March 1, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Masatoshi Sakurai, Kaori Kimura, Hiroyuki Hyodo, Takeshi Iwasaki
  • Patent number: 8116022
    Abstract: According to one embodiment, a magnetic recording apparatus includes a magnetic recording medium including magnetically recordable recording tracks with a width L1, non-recording sections each provided between adjacent recording tracks, and a wide land track having a width L2 larger than the width L1 of the recording tracks, and a head slider including read and write heads.
    Type: Grant
    Filed: April 23, 2010
    Date of Patent: February 14, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masatoshi Sakurai, Kazuto Kashiwagi
  • Publication number: 20120028076
    Abstract: According to one embodiment, a magnetic recording medium includes a substrate, a soft magnetic layer, an underlayer, a magnetic recording layer, and a protective layer, wherein the magnetic recording layer is provided with a pattern including recording portions and non-recording portions, the non-recording portions have a composition that is equal to a composition obtained by demagnetizing the recording portions, the non-recording portions contain at least one metal element selected from the group consisting of vanadium and zirconium and at least one element selected from the group consisting of nitrogen, carbon, boron and oxygen, and the at least one element selected from the group consisting of nitrogen, carbon, boron and oxygen is contained in the non-recording portions at a higher content than the content of the at least one element selected from the group consisting of nitrogen, carbon, boron and oxygen in the recording portions.
    Type: Application
    Filed: July 1, 2011
    Publication date: February 2, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Takeshi Iwasaki, Kaori Kimura, Yoshiyuki Kamata, Masatoshi Sakurai
  • Publication number: 20120019960
    Abstract: According to one embodiment, a bit patterned medium includes a substrate, and a magnetic recording layer disposed above the substrate and including patterns of protrusions. Each of the protrusions contains a plurality of crystal grains. An average distance between the crystal grains is 0.5 to 3.0 nm in each of the protrusions. The protrusions include first protrusions each having a length of 1 ?m or more in a radial direction of the medium and second protrusions each having a length in the radial direction shorter than the length of the first protrusion in the radial direction. Each of the first protrusions has a nucleation field Hn for magnetization reversal and a coercive force Hc satisfying the inequalities, Hn?1.5 kOe and 0.5 kOe?Hc?Hn?1.5 kOe.
    Type: Application
    Filed: July 1, 2011
    Publication date: January 26, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Masatoshi Sakurai, Yousuke Isowaki, Soichi Oikawa
  • Patent number: 8102616
    Abstract: According to one embodiment, there is provided a magnetic recording medium having a data region in which a plurality of recording tracks, each including magnetic dots arrayed in a down-track direction with a pitch p, are formed in a cross-track direction, and a servo region including a preamble in which a plurality of lines of magnetic dots, which are arrayed in a cross-track direction with a pitch p, are formed at equal intervals in the down-track direction.
    Type: Grant
    Filed: December 20, 2010
    Date of Patent: January 24, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masatoshi Sakurai, Kazuto Kashiwagi, Akira Kikitsu
  • Patent number: 8097351
    Abstract: A magnetic recording apparatus has a magnetic recording media including a substrate and a magnetic layer containing magnetic patterns on the substrate, the magnetic layer including data zones to constitute recoding tracks and servo zones, the magnetic patterns of the servo zones being used as address bits, and a magnetic head configured to read signals from the magnetic recording media while flying over the magnetic recording media, in which, in a case where two magnetic patterns used as address bits on the servo zones corresponding to two adjacent recording tracks are arranged in such a manner that one corner of one magnetic pattern is closest to one corner of the other magnetic pattern, the corners of the two magnetic patterns are substantially separated from each other.
    Type: Grant
    Filed: January 30, 2006
    Date of Patent: January 17, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Takeshi Okino, Seiji Morita, Yoshiyuki Kamata, Satoshi Shirotori, Masatoshi Sakurai, Hiroaki Nakamura
  • Publication number: 20120009439
    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: September 20, 2011
    Publication date: January 12, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Kaori Kimura, Yoshiyuki Kamata, Satoshi Shirotori, Masatoshi Sakurai
  • Publication number: 20120002316
    Abstract: According to one embodiment, there is provided a magnetic recording apparatus including a head slider including read and write elements, and a magnetic recording medium including magnetically recordable recording tracks with a width L1, a wide land track with a width L2 larger than the width L1 of the recording track, and non-recording sections with a width G1 each provided between adjacent recording tracks. The width L1 of the recording track is smaller than a bottom read width BRW of the read and write elements, and the width L2 of the wide land track is larger than the bottom read width BRW of the read and write elements.
    Type: Application
    Filed: June 30, 2011
    Publication date: January 5, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Masatoshi SAKURAI, Kazuto Kashiwagi, Naoki Tagami
  • Publication number: 20120000885
    Abstract: According to one embodiment, a stamper manufacturing method includes forming a conductive material concentration gradient layer including the projections pattern, and a composition ratio of a buffering agent to a conductive material in the conductive material concentration gradient layer reducing in a thickness direction from a master side.
    Type: Application
    Filed: April 25, 2011
    Publication date: January 5, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Masatoshi Sakurai, Satoshi Shirotori, Seiji Morita, Shinobu Sugimura, Takuya Shimada, Yoshiyuki Kamata
  • Publication number: 20110317306
    Abstract: According to one embodiment, there is provided a magnetic recording medium which includes a plurality of magnetic dot rows in which there is a phase shift between adjacent dot rows, and dots are arranged in a zigzag manner in a predetermined number of dot rows which are simultaneously read.
    Type: Application
    Filed: April 21, 2011
    Publication date: December 29, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Akihiro Itakura, Masatoshi Sakurai, Kazuhito Shimomura
  • Patent number: 8077416
    Abstract: A magnetic recording medium has a RAM region and a ROM region. The RAM region includes a plurality of first tracks each having a first magnetic portion. The first magnetic portions in adjacent tracks are separated from each other. The ROM region includes a plurality of second tracks each having a second magnetic portion. A width of the second magnetic portions in a direction perpendicular to a track direction of the first tracks is larger than that of the first magnetic portions in the perpendicular direction.
    Type: Grant
    Filed: March 24, 2010
    Date of Patent: December 13, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masatoshi Sakurai, Seiji Morita, Akira Kikitsu, Yoshiyuki Kamata
  • Patent number: 8070968
    Abstract: According to one embodiment, this invention uses an ultraviolet-curable resin material for pattern transfer containing 80 to 95 wt % of isobornyl acrylate, 1 to 20 wt % of trifunctional acrylate, and 0.5 to 6 wt % of a polymerization initiator.
    Type: Grant
    Filed: March 11, 2010
    Date of Patent: December 6, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kazuyo Umezawa, Seiji Morita, Masatoshi Sakurai
  • Patent number: 8057689
    Abstract: According to one embodiment, a method of manufacturing a magnetic recording medium includes forming a first hard mask, a second hard mask and a resist on a magnetic recording layer, imprinting a stamper to the resist to transfer patterns of protrusions and recesses to the resist, removing residues remaining in the recesses of the patterned resist by means of a first etching gas, etching the second hard mask by means of the first etching gas using the patterned resist as a mask to transfer the patterns to the second hard mask, etching the first hard mask by means of a second etching gas different from the first etching gas using the second hard mask as a mask to transfer the patterns to the first hard mask, and performing ion beam etching in order to deactivate the magnetic recording layer exposed in the recesses and to remove the second hard mask.
    Type: Grant
    Filed: February 12, 2010
    Date of Patent: November 15, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yousuke Isowaki, Kaori Kimura, Yoshiyuki Kamata, Masatoshi Sakurai
  • Patent number: 8057214
    Abstract: A method for manufacturing a plate-like structure, the method including a step of transferring concave and convex patterns on a master to a surface of a transferred substrate by sandwiching the master provided with the concave and convex patterns and the transferred substrate, between a press surface of a hollow cylindrical upper and a press surface of a lower mold, and pressurizing central parts of the upper and lower molds to apply pressure to the master and the transferred substrate, wherein a compressive load imposed on inner peripheral portions of the upper and lower molds is blocked and distributed toward outer peripheries of the upper and lower molds.
    Type: Grant
    Filed: September 1, 2009
    Date of Patent: November 15, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Ryoichi Takahashi, Masatoshi Sakurai
  • Patent number: 8059368
    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: Grant
    Filed: June 2, 2010
    Date of Patent: November 15, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kaori Kimura, Masatoshi Sakurai, Akira Kikitsu, Yoshiyuki Kamata, Satoshi Shirotori, Hiroyuki Hieda
  • Publication number: 20110262580
    Abstract: According to one embodiment, a stamper manufacturing method comprises electroless plating by using a master includes a substrate, a conductive underlayer formed on the substrate and having catalytic activity, projecting patterns having no catalytic activity and partially formed on a surface of the conductive underlayer having catalytic activity, and regions in which the conductive underlayer having catalytic activity is exposed between the projecting patterns to deposite selectively an amorphous conductive layer between the projecting patterns and in the regions in which the conductive underlayer is exposed, and forming stamper projections, electroplating on the stamper projections includes the projecting patterns and the amorphous conductive layer by using the amorphous conductive layer and the conductive underlayer as electrodes to form a stamper main body made of a crystalline metal, and releasing a stamper includes the stamper projections and the stamper main body from the master.
    Type: Application
    Filed: March 31, 2011
    Publication date: October 27, 2011
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Masatoshi SAKURAI, Takuya SHIMADA, Shinobu SUGIMURA, Satoshi SHIROTORI
  • Publication number: 20110259849
    Abstract: According to one embodiment, a method for producing an imprint mold includes forming, on a substrate, a plurality of guides including a first wall surface and a second wall surface, wherein an angle between at least one of the first and second wall surfaces and an exposed substrate surface is 131° or less, applying a self-assembling material, which forms a sphere when phase-separated, to a guide groove area defined by the first wall surface, the second wall surface and the substrate surface, and self-assembling the self-assembling material to form a dot pattern, etching the substrate by using the dot pattern as a mask to transfer the dot pattern and forming an imprint mold by using the substrate with the dot pattern transferred as a master mold.
    Type: Application
    Filed: April 25, 2011
    Publication date: October 27, 2011
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Masatoshi Sakurai, Naoko Kihara, Hiroki Tanaka, Ryosuke Yamamoto, Akiko Yuzawa
  • Patent number: 8043516
    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: Grant
    Filed: March 9, 2009
    Date of Patent: October 25, 2011
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kaori Kimura, Yoshiyuki Kamata, Satoshi Shirotori, Masatoshi Sakurai
  • Publication number: 20110242706
    Abstract: According to one embodiment, a servo area of a magnetic recording medium includes magnetic dots arrayed at a period L0. The magnetic dots include a plurality of magnetic dot regions divided in the cross track direction. A width Wm in the down track direction of the mth magnetic dot region from the innermost circumference and a number Nm of dot rows in the down track direction of the mth region meet a relationship represented by L0{Nm?3/2?0.3}?Wm?L0{Nm?3/2+0.
    Type: Application
    Filed: March 2, 2011
    Publication date: October 6, 2011
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Masatoshi SAKURAI, Ryosuke YAMAMOTO, Naoko KIHARA, Akiko YUZAWA, Yoshiyuki KAMATA