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: 20120273456
    Abstract: According to one embodiment, a magnetic recording medium includes recording areas forming protrusions corresponding to servo signals and recording tracks and includes a crystalline magnetic layer, and non-recording areas comprising an amorphous damaged layer left in bottoms of recesses between the recording areas.
    Type: Application
    Filed: July 10, 2012
    Publication date: November 1, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Masatoshi Sakurai, Makoto Asakura
  • Patent number: 8300340
    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+0.3}??(1).
    Type: Grant
    Filed: March 2, 2011
    Date of Patent: October 30, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masatoshi Sakurai, Ryosuke Yamamoto, Naoko Kihara, Akiko Yuzawa, Yoshiyuki Kamata
  • Patent number: 8300341
    Abstract: According to one embodiment, a magnetic recording device based on shingled-write recording method comprises a magnetic storage medium, a recording head, and an actuator. The magnetic storage medium comprises dot rows wherein a phase shift is between adjacent rows. The recording head covers a predetermined number of dot rows of the magnetic storage medium and comprises an edge at one of the dot rows. The actuator configured to move a recording head by an amount equivalent to a dot row after recording is performed on one of the dot rows by the recording head.
    Type: Grant
    Filed: March 9, 2011
    Date of Patent: October 30, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Akihiro Itakura, Masatoshi Sakurai, Kazuhito Shimomura
  • Patent number: 8293387
    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: Grant
    Filed: August 26, 2009
    Date of Patent: October 23, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Masatoshi Sakurai
  • Patent number: 8289645
    Abstract: According to one embodiment, there is provided a magnetic disk apparatus having a magnetic disk having magnetic dot lines each including magnetic dots arrayed at equal intervals in a down track direction, and a read/write head which uses a plurality of adjacent magnetic dot lines as one track and sequentially performs read and write on the magnetic dots included in the magnetic dot lines constituting the track, in which the magnetic dots included in each of the magnetic dot lines in each track of the magnetic disk are displaced in the down track direction from the magnetic dots included in the adjacent dot line in the track depending on a possible skew angle between the read/write head and the track so that the magnetic dots are sequentially accessed by the read/write head.
    Type: Grant
    Filed: October 4, 2010
    Date of Patent: October 16, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Masatoshi Sakurai, Akira Kikitsu, Kazuto Kashiwagi
  • Publication number: 20120251655
    Abstract: According to one embodiment, a stamper is described with a surface that comprises patterns of protrusions and recessed. The arithmetic average roughness Ra of the surface is 1 nanometer (nm) or more and 5 nm or less.
    Type: Application
    Filed: June 8, 2012
    Publication date: October 4, 2012
    Inventors: Shinobu Sugimura, Kaori Kimura, Takuya Shimada, Yoshiyuki Kamata, Masatoshi Sakurai
  • Publication number: 20120237798
    Abstract: According to one embodiment, a magnetic recording medium is formed by performing gas ion irradiation by using a magnetism deactivating gas on a stack including a perpendicular magnetic recording layer, an Ru nonmagnetic underlayer containing a magnetism deactivating element selected from chromium, titanium, and silicon, and a nonmagnetic substrate. Before gas ion irradiation, the perpendicular magnetic recording layer contains platinum and at least one of iron and cobalt. Gas ion irradiation is performed using nitrogen gas alone or a gas mixture of nitrogen gas and at least one gas selected from the group consisting of helium, hydrogen, and B2H6.
    Type: Application
    Filed: November 10, 2011
    Publication date: September 20, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Takeshi Iwasaki, Kaori Kimura, Hiroyuki Hyodo, Masatoshi Sakurai
  • Publication number: 20120237795
    Abstract: According to one embodiment, a magnetic recording medium includes a substrate, a magnetic recording layer formed on the substrate and containing a magnetic material, and a protective layer. The magnetic recording layer includes a recording portion having patterns regularly arranged in the longitudinal direction, and a non-recording portion having saturation magnetization lower than that in the recording portion. The non-recording portion contains the magnetic material, a deactivating species which makes the value of saturation magnetization smaller than that of saturation magnetization in the recording portion, and the component of the protective layer.
    Type: Application
    Filed: November 14, 2011
    Publication date: September 20, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: MASATOSHI SAKURAI, KAORI KIMURA, HIROYUKI HYODO, TAKESHI IWASAKI
  • Patent number: 8257560
    Abstract: A patterned media has a substrate, and a magnetic recording layer on the substrate including protruded magnetic patterns and a nonmagnetic material filled in between the protruded magnetic patterns. In the patterned media, a depth Db and a depth Da, which are defined that Db is a depth from a surface of the magnetic patterns to a surface of the nonmagnetic material filled in a first central part between the magnetic patterns adjacent to each other in a cross-track direction or a down-track direction, and Da is a depth from a surface of the magnetic patterns to a surface of the nonmagnetic material filled in a second central part in a portion surrounded by the magnetic patterns, have a relationship that the depth Da is greater than the depth Db.
    Type: Grant
    Filed: August 2, 2010
    Date of Patent: September 4, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Yoshiyuki Kamata, Masatoshi Sakurai, Satoshi Shirotori, Kaori Kimura
  • Publication number: 20120194937
    Abstract: According to one embodiment, a magnetic recording apparatus configured to record information onto a magnetic recording medium by a shingled write recording method, the magnetic recording apparatus includes: a recording head configured to cover a plurality of dot arrays and an end portion of which is situated at one dot array of a recording target; an actuator configured to move the recording head by one array after the recording to one dot array by the recording head; and a controller configured to perform recording compensation of the magnetic dot based on prestored recording data of a peripheral dot of a magnetic dot when input user data is recorded to the magnetic dot.
    Type: Application
    Filed: January 24, 2012
    Publication date: August 2, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Naoki TAGAMI, Kazuto KASHIWAGI, Akihiro ITAKURA, Haruhiko IZUMI, Masatoshi SAKURAI
  • Patent number: 8221637
    Abstract: According to one embodiment, a method for manufacturing a magnetic recording medium includes forming patterns having protrusions and recesses of a ferromagnetic material onto a recording track section and a servo section on a substrate, forming a flattening film, a top surface of which is higher than that of the protrusion of the ferromagnetic material, onto the ferromagnetic material, and performing ion beam etching onto the flattening film up to a top surface of the protrusion of the ferromagnetic material, and determining an end point of flattening etching on the basis of a change in the total number of incident particles by means of an ion counter installed so as to be at an angle ? with respect to a perpendicular direction to the substrate in accordance with a material of the flattening film.
    Type: Grant
    Filed: July 2, 2010
    Date of Patent: July 17, 2012
    Assignees: Kabushiki Kaisha Toshiba, Showa Denko K.K.
    Inventors: Yoshiyuki Kamata, Katsuyuki Naito, Akira Kikitsu, Masatoshi Sakurai, Masahiro Oka
  • Publication number: 20120177948
    Abstract: According to one embodiment, a method of manufacturing a patterned medium includes depositing a magnetic recording layer and applying an ultraviolet curable resin on both surfaces of a medium substrate, pressing a first resin stamper and a second resin stamper each including patterns of recesses and protrusions, corresponding to a patterned medium, against both surfaces of the medium substrate in such a manner that a direction from a center of the medium substrate toward a center of the first resin stamper is off-oriented from a direction from the center of the medium substrate toward a center of the second resin stamper to imprint the patterns of recesses and protrusions on the ultraviolet curable resin, and irradiating the ultraviolet curable resin with an ultraviolet ray through each of the first and second resin stampers to cure the ultraviolet curable resin.
    Type: Application
    Filed: March 19, 2012
    Publication date: July 12, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Akira Kikitsu, Yoshiyuki Kamata, Masatoshi Sakurai
  • Patent number: 8206602
    Abstract: According to one embodiment, there is provided a method of manufacturing a magnetic recording medium, including forming a first hard mask including carbon as a main component, a second hard mask including a main component other than carbon and a resist on a magnetic recording layer, contacting a stamper to the resist to transfer patterns of protrusions and recesses to the resist, removing residues in the recesses of the patterned resist, etching the second hard mask, etching the first hard mask, patterning the magnetic recording layer, and removing the first hard mask, the method further including, between etching the first hard mask and removing the first hard mask, removing the second hard mask remaining on the protrusions of the first hard mask, and removing a contaminating layer on a surface of the first hard mask by a mixed gas of oxygen-based gas and a fluorine compound.
    Type: Grant
    Filed: July 16, 2010
    Date of Patent: June 26, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kaori Kimura, Yousuke Isowaki, Yoshiyuki Kamata, Masatoshi Sakurai
  • Patent number: 8173029
    Abstract: According to one embodiment, a cured first ultraviolet-curing resin material layer having a first three-dimensional pattern is formed on a first principal surface of a magnetic recording medium having a central hole. A cured second ultraviolet-curing resin material layer having a second three-dimensional pattern is formed on a second principal surface opposite to the first principal surface of the magnetic recording.
    Type: Grant
    Filed: March 16, 2010
    Date of Patent: May 8, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Seiji Morita, Shinobu Sugimura, Kazuyo Umezawa, Masatoshi Sakurai
  • Patent number: 8159767
    Abstract: According to one embodiment, a stamper has three-dimensional patterns in a dummy region. The three-dimensional patterns have a repeatable run out of 1 nm or less between the 15th and 40th orders when the rotational frequency is the first order as a reference.
    Type: Grant
    Filed: August 10, 2009
    Date of Patent: April 17, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kazuyo Umezawa, Seiji Morita, Masatoshi Sakurai
  • Publication number: 20120087039
    Abstract: According to one embodiment, a magnetic recording medium includes a substrate, and a magnetic recording layer formed on the substrate. The magnetic recording layer includes recording portions having patterns regularly arranged in an longitudinal direction and containing cobalt and platinum, and non recording portions formed between the recording portions and containing boron and at least one light rare earth metal selected from the group consisting of yttrium, lanthanum, and cerium.
    Type: Application
    Filed: June 20, 2011
    Publication date: April 12, 2012
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Takeshi Iwasaki, Kaori Kimura, Yoshiyuki Kamata, Tsuyoshi Onitsuka, Masatoshi Sakurai
  • Patent number: 8153205
    Abstract: According to one embodiment, a method of manufacturing a patterned medium includes depositing a magnetic recording layer and applying an ultraviolet curable resin on both surfaces of a medium substrate, pressing a first resin stamper and a second resin stamper each including patterns of recesses and protrusions, corresponding to a patterned medium, against both surfaces of the medium substrate in such a manner that a direction from a center of the medium substrate toward a center of the first resin stamper is off-oriented from a direction from the center of the medium substrate toward a center of the second resin stamper to imprint the patterns of recesses and protrusions on the ultraviolet curable resin, and irradiating the ultraviolet curable resin with an ultraviolet ray through each of the first and second resin stampers to cure the ultraviolet curable resin.
    Type: Grant
    Filed: February 25, 2010
    Date of Patent: April 10, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Akira Kikitsu, Yoshiyuki Kamata, Masatoshi Sakurai
  • Publication number: 20120082800
    Abstract: According to one embodiment, there is provided a method for manufacturing a magnetic recording medium, the method including: depositing a magnetic recording layer on a substrate; forming a mask on a region of the magnetic recording layer corresponding to a recording area; irradiating another region of the magnetic recording layer where the mask is not formed with an ion beam using a C-containing gas as a source gas to deactivate the another region and to thereby form a non-recording area; and forming a protective film over an entire surface of the substrate.
    Type: Application
    Filed: August 24, 2011
    Publication date: April 5, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Masatoshi SAKURAI, Kaori Kimura, Yoshiyuki Kamata, Takeshi Iwasaki
  • Patent number: 8142693
    Abstract: According to one embodiment, letting Vf be a maximum voltage value level within the range of a frequency 60 to 170 times the rotational speed of a stamper and Vave be the average sum signal voltage value of a data recording portion in the sum signal of a voltage signal when the data recording portion is irradiated with a laser having a wavelength of 450 nm or less and an NA of 0.6 or more, whether Vf and Vave meet Vf/Vave<7.7×10?4 . . . (1) is determined.
    Type: Grant
    Filed: September 29, 2009
    Date of Patent: March 27, 2012
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Kazuyo Umezawa, Seiji Morita, Masatoshi Sakurai
  • Publication number: 20120063028
    Abstract: According to one embodiment, there is provided a magnetic recording apparatus including a bit-patterned medium having a data area including magnetic dot rows each of which includes magnetic dots, a magnetic head having a width covering a plurality of magnetic dot rows, and an actuator configured to actuate the magnetic head in a cross-track direction. The magnetic dots included in a n-th magnetic dot row have a higher coercivity than the magnetic dots included in a (n+1)-th magnetic dot row.
    Type: Application
    Filed: August 12, 2011
    Publication date: March 15, 2012
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Masatoshi SAKURAI, Akihiro Itakura, Kazuto Kashiwagi