Patents by Inventor Akira Sakawaki

Akira Sakawaki 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: 20100277829
    Abstract: A method for producing a magnetic recording medium having a magnetically partitioned magnetic recording pattern on at least one surface of a nonmagnetic substrate, characterized by comprising a step of reacting portions of a magnetic layer, formed on the non-magnetic substrate, with ozone to modify magnetic properties of said portions of the magnetic layer for forming the magnetically partitioned magnetic recording pattern. The magnetic layer can be a two-layer structure comprising a magnetic layer having a granular structure and formed thereon a magnetic layer having a non-granular structure. The produced magnetic recording medium exhibits a greatly enhanced recording density while recording/reproducing characteristics equal to or better than those of the heretofore proposed magnetic recording mediums are maintained, and it can be produced with an enhanced efficiency.
    Type: Application
    Filed: December 24, 2008
    Publication date: November 4, 2010
    Applicant: SHOWA DENKO K.K.
    Inventors: Masato Fukushima, Akira Sakawaki, Akira Yamane
  • Publication number: 20100271730
    Abstract: A method for producing a magnetic recording medium having a magnetically partitioned magnetic recording pattern on a surface of a nonmagnetic substrate, which comprises the following steps. Step (A) of forming a magnetic layer on a non-magnetic substrate, step (B) of forming a carbon layer on the magnetic layer, step (C) of forming a resist layer on the carbon layer, step (D) of forming a negative pattern of magnetic recording pattern on the resist layer, step (E) of removing the portions of resist layer and carbon layer in regions corresponding to the negative pattern, step (F) of removing at least a surface layer portion of the magnetic layer in the regions corresponding to the negative pattern, and optional step (G) of removing the residual resist layer and carbon layer. The produced magnetic recording medium has a recording/reproducing property equal to or better than conventional ones and exhibits a high recording density.
    Type: Application
    Filed: November 28, 2008
    Publication date: October 28, 2010
    Applicant: SHOWA DENKO K.K.
    Inventors: Masato Fukushima, Akira Sakawaki, Akira Yamane
  • Publication number: 20100232056
    Abstract: Provided is a process for manufacturing a magnetic recording medium having a magnetically partitioned magnetic recording patterns, which comprises the following steps, conducted in the order: (1) step of forming a magnetic layer on a non-magnetic substrate, (2) step of exposing the surface of regions of the magnetic layer to a reactive plasma or a reactive ion, which regions are to magnetically partition the magnetic layer for forming a magnetically partitioned magnetic recording pattern, and (3) step of exposing the magnetically partitioned magnetic layer to an inert gas irradiation. Preferably, a step of removing surface layer portions of said regions of the magnetic layer is carried out after the step (1) but before the step (2). The surface of the magnetic layer of produced magnetic recording medium exhibits good resistance to corrosion caused by oxidation or halogenation.
    Type: Application
    Filed: September 22, 2008
    Publication date: September 16, 2010
    Applicant: Showa Denko K.K.
    Inventors: Masato Fukushima, Akira Sakawaki, Akira Yamane
  • Publication number: 20100232052
    Abstract: Provided is a process for making a magnetic recording medium having a magnetically partitioned magnetic recording patterns, which comprises the following three steps (1), (2) and (3), conducted in this order: (1) a step of forming a magnetic layer on a non-magnetic substrate; (2) a step of removing surface layer portions of regions for magnetically partitioning the magnetic layer; and (3) a step of exposing the thus-exposed regions of the magnetic layer, from which the surface layer portions have been removed, to a reactive plasma or a reactive ion, to modify the magnetic characteristics of the regions of magnetic layer, whereby a magnetic recording pattern is formed which are magnetically partitioned by the regions of magnetic layer having the modified characteristics. Thus, a magnetic recording medium having an enhanced recording density and minimizing letter bleeding at writing can be made with a high efficiency.
    Type: Application
    Filed: July 24, 2008
    Publication date: September 16, 2010
    Applicant: SHOWA DENKO K.K.
    Inventors: Masato Fukushima, Akira Sakawaki, Akira Yamane
  • Patent number: 7781081
    Abstract: A magnetic recording medium 62 wherein a substrate 11, undercoating layers 13 and 14 formed on the substrate 11, and a magnetic recording layer 15, which include the magnetic crystal grain and the grain boundary field which encloses magnetic crystal grains, are included. The grain boundary field includes Ti oxide, and the ratio of the substance amount of the Ti oxide in the magnetic recording layer 15 is 5 mol % or more and 15 mol % or less, and the Ti oxide includes at least TiO and/or Ti2O3s.
    Type: Grant
    Filed: December 24, 2004
    Date of Patent: August 24, 2010
    Assignees: Showa Denko K.K., Kabushiki Kaisha Toshiba
    Inventors: Tomoyuki Maeda, Soichi Oikawa, Takeshi Iwasaki, Futoshi Nakamura, Hiroshi Sakai, Kenji Shimizu, Akira Sakawaki
  • Publication number: 20100196596
    Abstract: Provided are a double-sided coating apparatus and a method for double-sided coating with a coating solution configured to uniformly apply a coating solution to both surfaces of a substrate having a central opening in a simple process while preventing ingress of the coating solution to the central opening. A coating apparatus 1 according to the invention applies a coating solution to both main surfaces of a substrate 2 having a central opening 2a.
    Type: Application
    Filed: September 12, 2008
    Publication date: August 5, 2010
    Applicant: Showa Denko K.K.
    Inventors: Katsumasa Hirose, Akira Sakawaki, Masato Fukushima
  • Publication number: 20100165504
    Abstract: The present invention aims to provide a method of producing a magnetic recording medium which is a method of producing a magnetic recording medium having a magnetically-separated magnetic recording pattern, the method including: forming a magnetic layer on a non-magnetic substrate; then exposing a surface of the magnetic layer partially to reactive plasma, or a reactive ion generated in the plasma to amorphize the portion of the magnetic layer.
    Type: Application
    Filed: June 17, 2008
    Publication date: July 1, 2010
    Inventors: Masato Fukushima, Akira Sakawaki, Yasumasa Sasaki
  • Publication number: 20100149680
    Abstract: The present invention provides a method of manufacturing a magnetic recording medium where at least a magnetic layer is formed on a non-magnetic substrate and a magnetically separated magnetic recording pattern is formed on the magnetic layer, including: a magnetic recording pattern forming process of forming magnetic recording areas that are constructed with convex portions and boundary areas that are constructed with concave portions between the magnetic recording area as the magnetic recording pattern on the magnetic layer; followed by a protective layer forming process of forming a protective carbon layer by using a high-frequency plasma chemical vapor deposition method and by applying a negative bias to the non-magnetic substrate to make the protective carbon layer on the magnetic recording area thinner than the protective carbon layer on the boundary area.
    Type: Application
    Filed: December 9, 2009
    Publication date: June 17, 2010
    Applicant: SHOWA DENKO K.K.
    Inventors: Shinichi ISHIBASHI, Masato FUKUSHIMA, Akira SAKAWAKI
  • Publication number: 20100053813
    Abstract: A method for manufacturing a magnetic recording medium (30) having magnetically separate magnetic recording patterns on at least one surface of a nonmagnetic substrate (1), includes the steps of forming a magnetic layer (2) on the nonmagnetic substrate, forming a mask layer (3) on the magnetic layer, forming a resist layer (4) on the mask layer, transferring negative patterns of the magnetic recording patterns to the resist layer using a stamp (5), removing portions of the mask layer which correspond to the negative patterns of the magnetic recording patterns, implanting ions in the magnetic layer from a resist layer-side surface to partly demagnetize the magnetic layer, and removing the resist layer and the mask layer.
    Type: Application
    Filed: November 21, 2007
    Publication date: March 4, 2010
    Inventors: Masato Fukushima, Akira Sakawaki
  • Publication number: 20100053797
    Abstract: A method for manufacturing a magnetic recording medium includes the steps of depositing a magnetic layer on at least one of surfaces of a nonmagnetic substrate and injecting atoms partially in the magnetic layer, thereby demagnetizing parts having admitted the injected atoms or imparting amorphousness thereto, to form a magnetically separated magnetic recording pattern. The step of injecting includes the steps of applying resist to the at least one surface subsequent to the step of depositing, partially decreasing a thickness of the resist and irradiating a surface of the resist with atoms, thereby inducing partial injection of the atoms to the magnetic layer through portions of the resist decreased in thickness.
    Type: Application
    Filed: August 22, 2007
    Publication date: March 4, 2010
    Applicant: SHOWA DENKO K.K.
    Inventors: Masato Fukushima, Akira Sakawaki, Katsumasa Hirose
  • Publication number: 20100015356
    Abstract: An in-line film forming apparatus is provided which prevents uneven processing from occurring when reactive plasma treatment or ion irradiation treatment is performed on a substrate held by a carrier. A carrier (25) includes a holder (28) provided with a hole (29) which allows a substrate to be disposed therein, and a plurality of supporting members (30) attached to the periphery of the hole (29) of the holder (28) in an elastically deformable manner, and is capable of detachably holding the substrate fitted into the inside of the supporting members (30) while an outer peripheral portion of the substrate is made to abut on the plurality of supporting members (30). Within a chamber which performs reactive plasma treatment or ion irradiation treatment on the substrate held by the carrier (25), a ring member (32) having an opening (32a) in a position corresponding to the substrate is disposed so as to face at least one surface or both surfaces of the substrate held by the carrier (25).
    Type: Application
    Filed: July 6, 2009
    Publication date: January 21, 2010
    Applicant: SHOWA DENKO K.K.
    Inventors: Masato FUKUSHIMA, Akira Sakawaki, Tomoo Shige
  • Publication number: 20100007985
    Abstract: One object of the present invention is to provide a method for producing a magnetic recording medium which has excellent magnetic separation properties of the magnetic recording pattern, the present invention providing a method for producing a magnetic recording medium having a magnetic recording pattern which is magnetically separated, comprising the steps of: after laminating at least a magnetic layer and a carbon protective layer on a non-magnetic substrate in this order, partially irradiating with a reactive plasma containing carbon and a halogen or reactive ions which are generated in the reactive plasma on a surface of the carbon protective layer, and thereby forming a halogenated carbon protective layer, which is obtained by partially halogenating the carbon protective layer, and the magnetic recording pattern separated magnetically which is obtained by partially improving the magnetic layer.
    Type: Application
    Filed: July 7, 2009
    Publication date: January 14, 2010
    Applicant: SHOWA DENKO K. K.
    Inventors: Masato FUKUSHIMA, Akira Sakawaki
  • Publication number: 20090323219
    Abstract: A method for the production of a magnetic recording medium (30) includes the steps of depositing a magnetic layer or Co-containing magnetic layer (3) on at least one side of a nonmagnetic substrate (1) and partially implanting atoms into the magnetic layer or Co-containing magnetic layer to partially unmagnetize the magnetic layer or Co-containing magnetic layer, thereby forming nonmagnetic parts (4) and a magnetic recording pattern magnetically separated by the nonmagnetic parts and, in the case of the Co-containing magnetic layer, lowering Co (002) or Co (110) peak strength of a relevant part of the Co-containing magnetic layer as determined by the X-ray diffraction to ½ or less.
    Type: Application
    Filed: February 6, 2007
    Publication date: December 31, 2009
    Applicant: SHOWA DENKO K.K.
    Inventors: Masato Fukushima, Akira Sakawaki, Yasumasa Sasaki
  • Publication number: 20090290255
    Abstract: A manufacturing method which is capable of easily and inexpensively manufacturing discrete track-type magnetic recording media is provided. A method of manufacturing magnetic recording media having a main surface on which magnetic tracks 4 are disposed in a substantially concentric arrangement and on which grooves 5 for magnetically separating radially adjoining magnetic tracks 4 from one another are formed is characterized by forming on a flat substrate 1 at least a magnetic recording layer 2 so as to fabricate a workpiece 1a, then pressing a stamper having protrusions corresponding to the grooves 5 against a main surface of the workpiece so as to transfer the shape of the protrusions to the workpiece and form grooves 5 between the magnetic tracks 4.
    Type: Application
    Filed: November 7, 2006
    Publication date: November 26, 2009
    Applicant: SHOWA DENKO K.K.
    Inventor: Akira Sakawaki
  • Publication number: 20090290250
    Abstract: A discrete track-type magnetic recording medium (30) includes a nonmagnetic substrate (1), a magnetic recording track and a servo signal pattern which are provided on at least one side of the nonmagnetic substrate, and a nonmagnetic part (4) consisting of a nonmagnetic alloy containing Si for physically separating the magnetic recording track and the servo signal pattern. A magnetic recording and reproducing device comprising, in combination, the magnetic recording medium (30), a driving part (26) serving to drive the magnetic recording medium in a direction of recording, a magnetic head (27) composed of a recording part and a reproducing part, a device (28) to impart motion to the magnetic head relative to the magnetic recording medium, and a recording and reproducing signal processing device (29) for entering a signal into the magnetic head and reproducing an output signal from the magnetic head.
    Type: Application
    Filed: February 13, 2007
    Publication date: November 26, 2009
    Applicant: SHOWA DENKO K.K.
    Inventors: Masato Fukushima, Akira Sakawaki, Yasumasa Sasaki
  • Patent number: 7601445
    Abstract: To make possible high density recording by making the structure of the perpendicular magnetic recording layer finer. A perpendicular magnetic recording medium 10 includes at least a nonmagnetic under layer 2, a perpendicular magnetic layer 3, and a protective layer which are stacked on a nonmagnetic substrate 1, wherein the perpendicular magnetic layer includes ferromagnetic crystal grains and nonmagnetic crystal grain boundary regions, wherein the crystal grain boundary region includes at least two kinds of oxide.
    Type: Grant
    Filed: September 22, 2004
    Date of Patent: October 13, 2009
    Assignees: Showa Denko K.K., Kabushiki Kaisha Toshiba
    Inventors: Takeshi Iwasaki, Soichi Oikawa, Futoshi Nakamura, Tomoyuki Maeda, Hiroshi Sakai, Akira Sakawaki, Kenji Shimizu
  • Publication number: 20090237838
    Abstract: A method of manufacturing magnetic recording media with a high areal recording density, in which there write bleeding during magnetic recording is eliminated by reducing insofar as possible the coercive force and remanent magnetization in areas between magnetic tracks, is provided. The method of manufacture can produce magnetic recording media 10, in which a magnetic layer 3 is provided on at least one surface of a nonmagnetic substrate 1, and a magnetically separated magnetic pattern 3a is formed in this magnetic layer 3; by implanting atoms into the magnetic layer 3 with a uniform distribution in the thickness direction of the magnetic layer 3, and partially rendering nonmagnetic the magnetic layer 3, nonmagnetic portions 5 which magnetically separate the magnetic pattern 3a are formed.
    Type: Application
    Filed: August 16, 2007
    Publication date: September 24, 2009
    Applicant: SHOWA DENKO K.K.
    Inventors: Masato Fukushima, Akira Sakawaki
  • Publication number: 20090180213
    Abstract: A discrete track-type magnetic recording medium (30) includes a nonmagnetic substrate (1), a magnetic recording track and a servo signal pattern that are provided on at least one side of the nonmagnetic substrate and a part (4) nonmagnetized through implantation (7) of ions from above a mask (6) having a shape of a pattern expected to be separated for physically separating the magnetic recording track and the servo signal pattern. A magnetic recording and reproducing device includes the magnetic recording medium (30), a driving part (26) serving to drive the magnetic recording medium in a direction of recording, a magnetic head (27) composed of a recording part and a reproducing part, means (28) to impart motion to the magnetic head relative to the magnetic recording medium and recording and reproducing signal processing means (29) for entering a signal into the magnetic head and reproducing an output signal from the magnetic head.
    Type: Application
    Filed: February 19, 2007
    Publication date: July 16, 2009
    Applicant: SHOWA DENKO K.K.
    Inventors: Masato Fukushima, Akira Sakawaki, Yasumasa Sasaki
  • Publication number: 20090141399
    Abstract: A magnetic-recording medium which is provided on a nonmagnetic substrate with at least an orientation-controlling layer for controlling the orientation of a layer formed directly thereon, a perpendicularly magnetic layer having an easily magnetizing axis oriented mainly perpendicularly relative to the nonmagnetic substrate, and a protective layer. The perpendicularly magnetic layer includes two or more magnetic layers, at least one of the magnetic layers is a layer having Co as a main component and containing Pt as well and containing an oxide, and at least another of the magnetic layers is a layer having Co as a main component and containing Cr as well and containing no oxide.
    Type: Application
    Filed: November 20, 2008
    Publication date: June 4, 2009
    Applicants: SHOWA DENKO K.K., KABUSHIKI KAISHA TOSHIBA
    Inventors: Akira SAKAWAKI, Kenji Shimizu, Kazuo Kobayashi, Hiroshi Sakai, Soichi Oikawa, Takeshi Iwasaki, Tomoyuki Maeda, Futoshi Nakamura
  • Patent number: 7470474
    Abstract: A magnetic recording medium which is provided on a nonmagnetic substrate 1 with at least an orientation-controlling layer 3 for controlling the orientation of a layer formed directly thereon, a perpendicularly magnetic layer 4 having an easily magnetizing axis oriented mainly perpendicularly relative to the nonmagnetic substrate 1, and a protective layer 5 and characterized in that the perpendicularly magnetic layer 4 includes two or more magnetic layers, that at least one of the magnetic layers is a layer 4a having Co as a main component and containing Pt as well and containing an oxide and that at least another of the magnetic layers is a layer 4b having Co as a main component and containing Cr as well and containing no oxide.
    Type: Grant
    Filed: April 7, 2004
    Date of Patent: December 30, 2008
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Akira Sakawaki, Kenji Shimizu, Kazuo Kobayashi, Hiroshi Sakai, Soichi Oikawa, Takeshi Iwasaki, Tomoyuki Maeda, Futoshi Nakamura