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).
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Patent number: 11322176Abstract: 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: GrantFiled: June 9, 2020Date of Patent: May 3, 2022Assignees: SHOWA DENKO K.K., The School Corporation Kansai UniversityInventors: Hiroshi Tani, Hiroshi Sakai, Eishin Yamakawa, Kazuki Shindo
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Patent number: 10888895Abstract: 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: GrantFiled: February 13, 2018Date of Patent: January 12, 2021Assignees: SHOWA DENKO K.K., A SCHOOL CORPORATION KANSAI UNIVERSITYInventors: Hiroshi Tani, Hiroshi Sakai, Eishin Yamakawa, Kazuki Shindo
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Publication number: 20200395045Abstract: 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: ApplicationFiled: June 9, 2020Publication date: December 17, 2020Inventors: Hiroshi TANI, Hiroshi Sakai, Eishin Yamakawa, Kazuki Shindo
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Patent number: 10199064Abstract: 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: GrantFiled: February 16, 2016Date of Patent: February 5, 2019Assignee: SHOWA DENKO K.K.Inventors: Yoshihiko Maruyama, Selvaraj Aanandha, Yuan Ai Khoo, Satoru Nakamura, Hiromitsu Tanuma, Eishin Yamakawa
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Publication number: 20180257105Abstract: 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: ApplicationFiled: February 13, 2018Publication date: September 13, 2018Applicants: SHOWA DENKO K.K., A SCHOOL CORPORATION KANSAI UNIVERSITYInventors: Hiroshi TANI, Hiroshi SAKAI, Eishin YAMAKAWA, Kazuki SHINDO
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Patent number: 10074396Abstract: 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: GrantFiled: September 14, 2016Date of Patent: September 11, 2018Assignee: SHOWA DENKO K.K.Inventors: Eishin Yamakawa, Katsuaki To, Saeko Hayase
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Patent number: 9640213Abstract: 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: GrantFiled: November 9, 2015Date of Patent: May 2, 2017Assignees: SHOWA DENKO K.K., JAPAN ATOMIC ENERGY AGENCYInventors: Kota Hasegawa, Takahiro Ukai, Eishin Yamakawa, Shiro Entani, Seiji Sakai
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Publication number: 20170084305Abstract: 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: ApplicationFiled: September 14, 2016Publication date: March 23, 2017Applicant: SHOWA DENKO K.K.Inventors: Eishin YAMAKAWA, Katsuaki TO, Saeko HAYASE
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Publication number: 20160240219Abstract: 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: ApplicationFiled: February 16, 2016Publication date: August 18, 2016Applicant: SHOWA DENKO K.K.Inventors: Yoshihiko MARUYAMA, Selvaraj AANANDHA, Yuan Ai KHOO, Satoru NAKAMURA, Hiromitsu TANUMA, Eishin YAMAKAWA
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Publication number: 20160148633Abstract: 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: ApplicationFiled: November 9, 2015Publication date: May 26, 2016Inventors: Kota HASEGAWA, Takahiro UKAI, Eishin YAMAKAWA, Shiro ENTANI, Seiji SAKAI
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Patent number: 8296931Abstract: 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: GrantFiled: July 16, 2008Date of Patent: October 30, 2012Assignee: Showa Denko K.K.Inventors: Hiroyoshi Okumura, Eishin Yamakawa
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Patent number: 7842331Abstract: 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: GrantFiled: August 21, 2007Date of Patent: November 30, 2010Assignee: Showa Denko K.K.Inventors: Eishin Yamakawa, Makoto Okada, Jun Fujii, Takako Yamauchi
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Publication number: 20090252992Abstract: 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: ApplicationFiled: June 19, 2009Publication date: October 8, 2009Applicant: FUJITSU LIMITEDInventors: Makoto Okada, Takuya Tomoi, Eishin Yamakawa, Yuki Yoshida
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Patent number: 7534750Abstract: 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: GrantFiled: February 24, 2005Date of Patent: May 19, 2009Assignee: Fujitsu LimitedInventors: Hiroshi Chiba, Yukiko Oshikubo, Keiji Watanabe, Eishin Yamakawa, Takeshi Toukairin
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Publication number: 20090061742Abstract: 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: ApplicationFiled: July 16, 2008Publication date: March 5, 2009Applicant: FUJITSU LIMITEDInventors: Hiroyoshi Okumura, Eishin Yamakawa
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Publication number: 20090059416Abstract: 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: ApplicationFiled: July 14, 2008Publication date: March 5, 2009Applicant: FUJITSU LIMITEDInventors: Makoto Okada, Eishin Yamakawa, Yoshihiro Mitobe
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Publication number: 20090053394Abstract: 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: ApplicationFiled: August 21, 2007Publication date: February 26, 2009Applicant: FUJITSU LIMITEDInventors: Eishin Yamakawa, Makoto Okada, Jun Fujii, Takako Yamauchi
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Publication number: 20080081220Abstract: 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: ApplicationFiled: November 15, 2007Publication date: April 3, 2008Applicant: Fujitsu LimitedInventors: Keiji Watanabe, Hiroshi Chiba, Eishin Yamakawa, Tsukasa Itani, Norikazu Nakamura, Shoichi Suda, Masayuki Takeda, Kazuaki Kurihara
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Patent number: 7335701Abstract: 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: GrantFiled: June 27, 2006Date of Patent: February 26, 2008Assignee: Fujitsu LimitedInventors: Keiji Watanabe, Hiroshi Chiba, Eishin Yamakawa, Tsukasa Itani, Norikazu Nakamura, Shoichi Suda, Masayuki Takeda, Kazuaki Kurihara
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Publication number: 20070203037Abstract: 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: ApplicationFiled: July 31, 2006Publication date: August 30, 2007Applicant: FUJITSU LIMITEDInventors: Hiroshi Chiba, Masaaki Sasa, Yukiko Oshikubo, Keiji Watanabe, Eishin Yamakawa, Takeshi Tokairin