Patents by Inventor Eishin Yamakawa

Eishin Yamakawa 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).

  • Patent number: 11322176
    Abstract: A method of manufacturing a magnetic recording medium forms an unfinished product including a magnetic recording layer and a protection layer that are successively formed on a substrate, and forms a lubricant layer on the protection layer of the unfinished product. The lubricant layer is formed by coating a first organic fluorine compound on the protection layer of the unfinished product, and supplying a gas, including a second organic fluorine compound, onto the protection layer of the unfinished product, and decomposing the second organic fluorine compound by Townsend discharge and ultraviolet ray irradiation. The protection layer includes carbon, and the first organic fluorine compound includes a functional group at a terminal thereof.
    Type: Grant
    Filed: June 9, 2020
    Date of Patent: May 3, 2022
    Assignees: SHOWA DENKO K.K., The School Corporation Kansai University
    Inventors: Hiroshi Tani, Hiroshi Sakai, Eishin Yamakawa, Kazuki Shindo
  • Patent number: 10888895
    Abstract: A film production method for producing a thin film on a surface of a workpiece, including the steps of: disposing the workpiece in a chamber; supplying a process gas into the chamber with the inside of the chamber being maintained at a predetermined pressure; applying a light having an energy between 3 eV and 10 eV to the surface of the workpiece to cause a photoelectron to be emitted from the surface of the workpiece; and applying an AC electric field to the surface of the workpiece, wherein the AC electric field has an electric field intensity causing a Townsend discharge to occur without generating a glow discharge plasma.
    Type: Grant
    Filed: February 13, 2018
    Date of Patent: January 12, 2021
    Assignees: SHOWA DENKO K.K., A SCHOOL CORPORATION KANSAI UNIVERSITY
    Inventors: Hiroshi Tani, Hiroshi Sakai, Eishin Yamakawa, Kazuki Shindo
  • Publication number: 20200395045
    Abstract: A method of manufacturing a magnetic recording medium forms an unfinished product including a magnetic recording layer and a protection layer that are successively formed on a substrate, and forms a lubricant layer on the protection layer of the unfinished product. The lubricant layer is formed by coating a first organic fluorine compound on the protection layer of the unfinished product, and supplying a gas, including a second organic fluorine compound, onto the protection layer of the unfinished product, and decomposing the second organic fluorine compound by Townsend discharge and ultraviolet ray irradiation. The protection layer includes carbon, and the first organic fluorine compound includes a functional group at a terminal thereof.
    Type: Application
    Filed: June 9, 2020
    Publication date: December 17, 2020
    Inventors: Hiroshi TANI, Hiroshi Sakai, Eishin Yamakawa, Kazuki Shindo
  • Patent number: 10199064
    Abstract: A magnetic recording medium which is capable of effectively preventing a surface thereof from being contaminated, and is capable of preventing a contaminant thereon from adhering (being transferred) to a magnetic head, and a magnetic recording and reproducing apparatus including the magnetic recording medium are provided, A carbon protective layer of the magnetic recording medium is nitrided, and as a lubricant a compound A expressed by the following General Formula (1) and a compound B expressed by the following General Formula (2) are mixed and used.
    Type: Grant
    Filed: February 16, 2016
    Date of Patent: February 5, 2019
    Assignee: SHOWA DENKO K.K.
    Inventors: Yoshihiko Maruyama, Selvaraj Aanandha, Yuan Ai Khoo, Satoru Nakamura, Hiromitsu Tanuma, Eishin Yamakawa
  • Publication number: 20180257105
    Abstract: A film production method for producing a thin film on a surface of a workpiece, including the steps of: disposing the workpiece in a chamber; supplying a process gas into the chamber with the inside of the chamber being maintained at a predetermined pressure; applying a light having an energy between 3 eV and 10 eV to the surface of the workpiece to cause a photoelectron to be emitted from the surface of the workpiece; and applying an AC electric field to the surface of the workpiece, wherein the AC electric field has an electric field intensity causing a Townsend discharge to occur without generating a glow discharge plasma.
    Type: Application
    Filed: February 13, 2018
    Publication date: September 13, 2018
    Applicants: SHOWA DENKO K.K., A SCHOOL CORPORATION KANSAI UNIVERSITY
    Inventors: Hiroshi TANI, Hiroshi SAKAI, Eishin YAMAKAWA, Kazuki SHINDO
  • Patent number: 10074396
    Abstract: In a magnetic recording medium of the present invention, an outermost surface of a protective layer 3 on a lubricant layer 4 side contains carbon and nitrogen in a range of 50 atomic % to 90 atomic %, and the lubricant layer 4 is formed by being in contact with the outermost surface, contains compounds A to C represented in the below general formulas (1) to (3) described below, and has a film thickness of 0.5 nm to 2 nm.
    Type: Grant
    Filed: September 14, 2016
    Date of Patent: September 11, 2018
    Assignee: SHOWA DENKO K.K.
    Inventors: Eishin Yamakawa, Katsuaki To, Saeko Hayase
  • Patent number: 9640213
    Abstract: A perpendicular magnetic recording medium includes a perpendicular magnetic layer provided above a nonmagnetic substrate, and a protection layer provided on the perpendicular magnetic layer. The perpendicular magnetic layer has an hcp structure, and includes stacked layers having a (0002) crystal plane oriented parallel to a surface of the nonmagnetic substrate. An uppermost layer amongst the stacked layers includes polycrystal grains selected from a CoCr-base alloy, a CoPt-base alloy, a CoCrPt-base alloy, and a CoPtCr-base alloy. The protection layer makes contact with the uppermost layer of the perpendicular magnetic layer, and includes a single graphene layer or a graphene stack, and an amorphous carbon layer. The single graphene layer or the graphene stack is bonded in parallel to a (0002) crystal plane of the polycrystal grains.
    Type: Grant
    Filed: November 9, 2015
    Date of Patent: May 2, 2017
    Assignees: SHOWA DENKO K.K., JAPAN ATOMIC ENERGY AGENCY
    Inventors: Kota Hasegawa, Takahiro Ukai, Eishin Yamakawa, Shiro Entani, Seiji Sakai
  • Publication number: 20170084305
    Abstract: In a magnetic recording medium of the present invention, an outermost surface of a protective layer 3 on a lubricant layer 4 side contains carbon and nitrogen in a range of 50 atomic % to 90 atomic %, and the lubricant layer 4 is formed by being in contact with the outermost surface, contains compounds A to C represented in the below general formulas (1) to (3) described below, and has a film thickness of 0.5 nm to 2 nm.
    Type: Application
    Filed: September 14, 2016
    Publication date: March 23, 2017
    Applicant: SHOWA DENKO K.K.
    Inventors: Eishin YAMAKAWA, Katsuaki TO, Saeko HAYASE
  • Publication number: 20160240219
    Abstract: A magnetic recording medium which is capable of effectively preventing a surface thereof from being contaminated, and is capable of preventing a contaminant thereon from adhering (being transferred) to a magnetic head, and a magnetic recording and reproducing apparatus including the magnetic recording medium are provided, A carbon protective layer of the magnetic recording medium is nitrided, and as a lubricant a compound A expressed by the following General Formula (1) and a compound B expressed by the following General Formula (2) are mixed and used.
    Type: Application
    Filed: February 16, 2016
    Publication date: August 18, 2016
    Applicant: SHOWA DENKO K.K.
    Inventors: Yoshihiko MARUYAMA, Selvaraj AANANDHA, Yuan Ai KHOO, Satoru NAKAMURA, Hiromitsu TANUMA, Eishin YAMAKAWA
  • Publication number: 20160148633
    Abstract: A perpendicular magnetic recording medium includes a perpendicular magnetic layer provided above a nonmagnetic substrate, and a protection layer provided on the perpendicular magnetic layer. The perpendicular magnetic layer has an hcp structure, and includes stacked layers having a (0002) crystal plane oriented parallel to a surface of the nonmagnetic substrate. An uppermost layer amongst the stacked layers includes polycrystal grains selected from a CoCr-base alloy, a CoPt-base alloy, a CoCrPt-base alloy, and a CoPtCr-base alloy. The protection layer makes contact with the uppermost layer of the perpendicular magnetic layer, and includes a single graphene layer or a graphene stack, and an amorphous carbon layer. The single graphene layer or the graphene stack is bonded in parallel to a (0002) crystal plane of the polycrystal grains.
    Type: Application
    Filed: November 9, 2015
    Publication date: May 26, 2016
    Inventors: Kota HASEGAWA, Takahiro UKAI, Eishin YAMAKAWA, Shiro ENTANI, Seiji SAKAI
  • Patent number: 8296931
    Abstract: According to an aspect of an embodiment, a method for manufacturing a storage medium includes providing a medium plate member for forming the storage medium and a guide member; and aligning the medium plate member and the guide member so that the medium plate member and the guide member are placed adjacently and the surfaces of the medium plate member and the guide member form a substantially common plane. The method further includes guiding a burnishing member for burnishing the medium plate member onto the surface of the guide member; and sliding the burnishing member on the guide member onto the medium plate member so as to burnish the surface of the medium plate member.
    Type: Grant
    Filed: July 16, 2008
    Date of Patent: October 30, 2012
    Assignee: Showa Denko K.K.
    Inventors: Hiroyoshi Okumura, Eishin Yamakawa
  • Patent number: 7842331
    Abstract: A manufacturing method of a magnetic recording medium having a surface where a lubricating layer is provided, the manufacturing method includes the steps of: applying a lubricant so that the lubricating layer is formed; and inspecting the magnetic recording medium where the lubricating layer is formed; wherein the step of inspecting includes a first step of floating a magnetic head over the magnetic recording medium or sliding the magnetic head on a surface of the magnetic recording medium; a second step of adhering a medium facing surface of the magnetic head to a surface of a substrate for measuring, standing the medium facing surface of the magnetic head on the surface of the substrate for measuring, and transferring the lubricant from the medium facing surface of the magnetic head to the substrate for measuring; a third step of measuring an amount of the lubricant on the surface of the substrate for measuring; and a fourth step of determining whether the amount of the lubricant is proper.
    Type: Grant
    Filed: August 21, 2007
    Date of Patent: November 30, 2010
    Assignee: Showa Denko K.K.
    Inventors: Eishin Yamakawa, Makoto Okada, Jun Fujii, Takako Yamauchi
  • Publication number: 20090252992
    Abstract: A magnetic recording medium has a recording layer, a protection layer and a lubricant layer that are stacked above a substrate. The lubricant layer includes a bond layer in contact with the protection layer, and a mobile layer at a surface of the magnetic recording medium and having a bonding strength weaker than that of the bond layer with respect to the protection layer. A height of convex portions at a surface portion of the mobile layer is approximately 0.3 nm or less.
    Type: Application
    Filed: June 19, 2009
    Publication date: October 8, 2009
    Applicant: FUJITSU LIMITED
    Inventors: Makoto Okada, Takuya Tomoi, Eishin Yamakawa, Yuki Yoshida
  • Patent number: 7534750
    Abstract: There are provided a composition that exhibits sufficient flowability and also displays high substrate adhesion, and a magnetic recording medium, a head slider and a magnetic recording device that use this composition as a lubricant and are thus not prone to faults. The composition comprises a fluorine-containing polyether represented by formula (1), (in formula (1), p and q represent, independently of the symbols in other formulae, any chosen integers). The composition can be produced by reacting a polymer represented by formula (2) with glycidol, HOCH2CF2O(CF2CF2O)p(CF2O)qCF2CH2OH??(2) (in formula (2), p and q represent, independently of the symbols in other formulae, any chosen integers).
    Type: Grant
    Filed: February 24, 2005
    Date of Patent: May 19, 2009
    Assignee: Fujitsu Limited
    Inventors: Hiroshi Chiba, Yukiko Oshikubo, Keiji Watanabe, Eishin Yamakawa, Takeshi Toukairin
  • Publication number: 20090061742
    Abstract: According to an aspect of an embodiment, a method for manufacturing a storage medium includes providing a medium plate member for forming the storage medium and a guide member; and aligning the medium plate member and the guide member so that the medium plate member and the guide member are placed adjacently and the surfaces of the medium plate member and the guide member form a substantially common plane. The method further includes guiding a burnishing member for burnishing the medium plate member onto the surface of the guide member; and sliding the burnishing member on the guide member onto the medium plate member so as to burnish the surface of the medium plate member.
    Type: Application
    Filed: July 16, 2008
    Publication date: March 5, 2009
    Applicant: FUJITSU LIMITED
    Inventors: Hiroyoshi Okumura, Eishin Yamakawa
  • Publication number: 20090059416
    Abstract: According to an aspect of an embodiment, an storage device includes a storage medium having a substrate, a storage medium layer for storing information, a first lubricating layer on a first area of the storage medium layer, and a second lubricating layer on a second area of the storage medium, the second lubricating layer having a viscosity lower than the first lubricating layer. The storage device further comprises a head for writing information into the storage medium layer or reading information from the storage medium layer.
    Type: Application
    Filed: July 14, 2008
    Publication date: March 5, 2009
    Applicant: FUJITSU LIMITED
    Inventors: Makoto Okada, Eishin Yamakawa, Yoshihiro Mitobe
  • Publication number: 20090053394
    Abstract: A manufacturing method of a magnetic recording medium having a surface where a lubricating layer is provided, the manufacturing method includes the steps of: applying a lubricant so that the lubricating layer is formed; and inspecting the magnetic recording medium where the lubricating layer is formed; wherein the step of inspecting includes a first step of floating a magnetic head over the magnetic recording medium or sliding the magnetic head on a surface of the magnetic recording medium; a second step of adhering a medium facing surface of the magnetic head to a surface of a substrate for measuring, standing the medium facing surface of the magnetic head on the surface of the substrate for measuring, and transferring the lubricant from the medium facing surface of the magnetic head to the substrate for measuring; a third step of measuring an amount of the lubricant on the surface of the substrate for measuring; and a fourth step of determining whether the amount of the lubricant is proper.
    Type: Application
    Filed: August 21, 2007
    Publication date: February 26, 2009
    Applicant: FUJITSU LIMITED
    Inventors: Eishin Yamakawa, Makoto Okada, Jun Fujii, Takako Yamauchi
  • Publication number: 20080081220
    Abstract: A magnetic disk is produced with improved yield by forming a DLC protective film by a d.c. magnetron sputtering process conducted in a sputtering atmosphere containing oxygen. The magnetic disk carries a lubricating film on the DLC film wherein a fluorocarbon resin constituting the lubricating film contains photocrosslinking groups. A lubricating film having non-polar end groups is also disclosed.
    Type: Application
    Filed: November 15, 2007
    Publication date: April 3, 2008
    Applicant: Fujitsu Limited
    Inventors: Keiji Watanabe, Hiroshi Chiba, Eishin Yamakawa, Tsukasa Itani, Norikazu Nakamura, Shoichi Suda, Masayuki Takeda, Kazuaki Kurihara
  • Patent number: 7335701
    Abstract: A magnetic disk is produced with improved yield by forming a DLC protective film by a d.c. magnetron sputtering process conducted in a sputtering atmosphere containing oxygen. The magnetic disk carries a lubricating film on the DLC film wherein a fluorocarbon resin constituting the lubricating film contains photocrosslinking groups. A lubricating film having non-polar end groups is also disclosed.
    Type: Grant
    Filed: June 27, 2006
    Date of Patent: February 26, 2008
    Assignee: Fujitsu Limited
    Inventors: Keiji Watanabe, Hiroshi Chiba, Eishin Yamakawa, Tsukasa Itani, Norikazu Nakamura, Shoichi Suda, Masayuki Takeda, Kazuaki Kurihara
  • Publication number: 20070203037
    Abstract: A lubricant is provided that achieves a sufficiently small one-molecule-layer film thickness even when it has a high molecular weight, and has an increased reliability in a wide temperature range environment without losing the flying stability, by making the film thickness of a lubricant layer very small when it is used for the magnetic recording medium lubricant layer and/or head slider lubricant layer of a magnetic recording device. This lubricant comprises a fluorine-containing polymer, the lubricant having a relationship: Y<?1.4475X+2.815, wherein Y is a natural logarithm of diffusion coefficient at 23° C. (unit:?m2/s); and X is a viscosity at 20° C. (unit: Pas), or it comprises a fluorine-containing polymer having a particular structure, and with molecular chains between adjacent polar groups that have a number-average molecular weight of not less than 500.
    Type: Application
    Filed: July 31, 2006
    Publication date: August 30, 2007
    Applicant: FUJITSU LIMITED
    Inventors: Hiroshi Chiba, Masaaki Sasa, Yukiko Oshikubo, Keiji Watanabe, Eishin Yamakawa, Takeshi Tokairin