Patents by Inventor Akira Nahara

Akira Nahara 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: 5413868
    Abstract: A magnetic recording medium comprising a nonmagnetic substrate having thereon a magnetic layer, wherein the magnetic layer is a metal thin film comprising mainly a composition represented by the formula: (Co.sub.100-x Pd.sub.x).sub.100-y Cr.sub.y or [(Co..sub.100-x Pd.sub.x).sub.100-y Cr.sub.y ].sub.100-z O.sub.z wherein x, y and z are atomic percents, and 10.ltoreq.x 40, 5.ltoreq.y.ltoreq.25 and 0.5.ltoreq.z.ltoreq.15. The present medium can be produced at low costs, and has excellent perpendicular magnetic anisotropy.
    Type: Grant
    Filed: September 2, 1993
    Date of Patent: May 9, 1995
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Satoshi Matsubaguchi, Akira Nahara
  • Patent number: 5311500
    Abstract: A magneto-optical disk comprises a substrate and at least a magneto-optical recording layer provided on the substrate. A moisture barrier layer constituted of a fluorine resin is provided on the surface of the substrate on the side opposite to the substrate surface on which the magneto-optical recording layer is provided.
    Type: Grant
    Filed: April 14, 1993
    Date of Patent: May 10, 1994
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Manabu Higuchi, Takashi Yamada, Masaaki Nomura, Akira Nahara
  • Patent number: 5109377
    Abstract: A magneto-optical recording medium has a substrate and a recording layer which is formed on the substrate. The recording layer is formed of a plurality of transition metal films and a plurality of rare earth metal films which are alternately formed one on the other, and at least a metal selected from the group consisting of Cr, Al and Ti is contained in the rare earth metal films or the transition metal films.
    Type: Grant
    Filed: August 22, 1989
    Date of Patent: April 28, 1992
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Ryoichi Yamamoto, Takashi Yamada, Satoshi Matsubaguchi, Akira Nahara
  • Patent number: 4994321
    Abstract: A perpendicular magnetic recording medium such as a floppy disk is created by providing on at least one surface of a non-magnetic support, a magnetic layer having perpendicular magnetic anisotropy and a protective layer by sputtering. First, a magnetic layer is provided, secondly, the magnetic layer is surface treated by a plasma treatment or by applying an oxide layer or a nitride layer thereon and thirdly, the protective layer is applied thereto.
    Type: Grant
    Filed: April 5, 1990
    Date of Patent: February 19, 1991
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Makoto Nagao, Kunihiko Sano, Fusao Yamanaka, Akira Nahara
  • Patent number: 4975339
    Abstract: A magneto-optical recording medium comprises a transparent substrate, a magneto-optical recording layer formed on the transparent substrate and containing a rare earth metal-transition metal alloy, and a thin film containing at least either one of platinum and palladium and formed at least on one surface of the magneto-optical recording layer. Or, the magneto-optical recording medium comprises the transparent substrate, and a magneto-optical recording layer formed on the transparent substrate by alternately overlaying a plurality of thin layers containing a rare earth metal-transition metal alloy, and a plurality of thin layers containing at least either one of platinum and palladium.
    Type: Grant
    Filed: September 16, 1988
    Date of Patent: December 4, 1990
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Takashi Yamada, Masaaki Nomura, Ryoichi Yamamoto, Akira Nahara
  • Patent number: 4929320
    Abstract: A method of making a magneto-optical recording medium comprises the step of forming a magneto-optical recording layer on a substrate by simultaneously carrying out direct current sputtering and radio-frequency sputtering. Alternatively, a magneto-optical recording layer composed of thin rare earth metal layers and thin transition metal layers overlaid alternately on a substrate is formed by carrying out radio-frequency sputtering by use of a target formed of a rare earth metal material and direct current sputtering by use of a target formed of a transition metal material.
    Type: Grant
    Filed: June 19, 1989
    Date of Patent: May 29, 1990
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Takashi Yamada, Masaaki Nomura, Ryoichi Yamamoto, Satoshi Matsubaguchi, Akira Nahara
  • Patent number: 4897320
    Abstract: A magneto-optical recording medium comprises a recording layer formed of a magnetic material, and a protective layer composed of a combination of a dielectric material with a rare earth metal exhibiting a high oxygen absorptivity and formed on the recording layer by a simultaneous sputtering or a simultaneous deposition process, whereby free oxygen given rise to in the course of sputtering or deposition is absorbed on the protective layer side before being absorbed on the recording layer side.
    Type: Grant
    Filed: August 11, 1988
    Date of Patent: January 30, 1990
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Masaaki Nomura, Takashi Yamada, Ryoichi Yamamoto, Akira Nahara
  • Patent number: 4869797
    Abstract: A method of preparing a magnetic recording medium in which a magnetic layer is deposited on a non-magnetic support and then a carbon protective layer is sputtered onto the magnetic layer. The sputtering is performed with a bias voltage of -10V to -100V being applied in the vicinity of the support and magnetic layer.
    Type: Grant
    Filed: June 18, 1987
    Date of Patent: September 26, 1989
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Makoto Nagao, Kunihiko Sano, Fusao Yamanaka, Akira Nahara
  • Patent number: 4867101
    Abstract: Contaminant magnetic dust particles and flakes generated during the thin film coating of a substrate 9 in a vacuum chamber 1 are gravitationally collected in catch pans or troughs 8 disposed below the deposition zones. Magnets 10 are provided under the bottoms of the pans to enhance the attraction and retention of the particles. The contaminants may alternatively or additionally be removed directly from an upper surface of the substrate web by sandwiching one or more of its horizontal conveyance runs between a pair of magnets 22, 23, with the pole face area of the lower magnet being larger than that of the upper one.
    Type: Grant
    Filed: July 10, 1987
    Date of Patent: September 19, 1989
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Fusao Yamanaka, Makoto Nagao, Akira Nahara
  • Patent number: 4868070
    Abstract: In a method of manufacturing a vertical magnetization type recording medium, a soft magnetic film layer is formed on each of the two sides of a non-magnetic support, and then a vertical magnetization film layer is formed on each soft magnetic film layer thus formed, thereby to provide a vertical magnetization type recording medium which has both sides uniform in characteristics and has characteristics making it excellent as a vertical magnetization type recording medium.
    Type: Grant
    Filed: June 10, 1987
    Date of Patent: September 19, 1989
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Makoto Nagao, Fusao Yamanaka, Akira Nahara
  • Patent number: 4865878
    Abstract: In a method of manufacturing a vertical magnetization type recording medium, a soft magnetic film layer is formed on each of the two sides of a non-magnetic support, and then a vertical magnetization film layer is formed on each soft magnetic film layer thus formed, thereby to provide a vertical magnetization type recording medium which has both sides uniform in characteristics and has characteristics making it excellent as a vertical magnetization type recording medium.This is a division of application Ser. No. 59,242 filed 6/10/87, which is a continuation of application Ser. No. 802,150 filed 11/27/85 both are now abandoned.
    Type: Grant
    Filed: June 7, 1988
    Date of Patent: September 12, 1989
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Makoto Nagao, Fusao Yamanaka, Akira Nahara
  • Patent number: 4840843
    Abstract: A magnetic recording medium is described, comprising a non-magnetic support having provided thereon a thin magnetic metal film and a protective layer mainly comprising carbon having a graphite structure containing at least one element selected from the group consisting of Mn, Mo, Nb, Ta, Ti, V, Cr and W.
    Type: Grant
    Filed: October 19, 1987
    Date of Patent: June 20, 1989
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Kunihiko Sano, Makoto Nagao, Akira Nahara, Yasuo Nishikawa, Hiroyuki Iwasaki
  • Patent number: 4837118
    Abstract: A magneto-optical recording medium comprises a transparent substrate and a magneto-optical recording layer overlaid on the transparent substrate. The magneto-optical recording layer is formed by alternately overlaying a plurality of thin layers containing a rare earth metal-transition metal alloy for magneto-optical recording, and a plurality of thin layers containing at least one metal selected from the group consisting of gold, silver, lead, magnesium, copper, and iridium which are solid solution non-formable metals.
    Type: Grant
    Filed: May 11, 1987
    Date of Patent: June 6, 1989
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Ryoichi Yamamoto, Masaaki Nomura, Takashi Yamada, Akira Nahara
  • Patent number: 4808456
    Abstract: A magneto-optical recording medium comprises a substrate, a magneto-optical recording layer formed of a rare earth metal-transition metal alloy and a dielectric protective layer overlaid in this order on the substrate, and a rare earth metal layer overlaid on an edge face of the magneto-optical recording layer.
    Type: Grant
    Filed: September 30, 1987
    Date of Patent: February 28, 1989
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Takashi Yamada, Masaaki Nomura, Ryoichi Yamamoto, Akira Nahara
  • Patent number: 4802160
    Abstract: An optical disk substrate has a surface on which a pre-groove for light beam tracking is formed. Non-pregrooved regions on the substrate surface on which the pregroove is formed are subjected to surface roughing processing to improve adhesion of the substrate surface in the non-pregrooved regions to a film which is to be overlaid on the optical disk substrate.
    Type: Grant
    Filed: October 5, 1987
    Date of Patent: January 31, 1989
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Takashi Yamada, Masaaki Nomura, Ryoichi Yamamoto, Akira Nahara
  • Patent number: 4789606
    Abstract: A magneto-optical recording medium comprises a transparent substrate, a magneto-optical recording layer formed on the transparent substrate and containing a rare earth metal-transition metal alloy, and a thin film containing at least either one of platinum and palladium and formed at least on one surface of the magneto-optical recording layer. Or, the magneto-optical recording medium comprises the transparent substrate, and a magneto-optical recording layer formed on the transparent substrate by alternately overlaying a plurality of thin layers containing a rare earth metal-transition metal alloy, and a plurality of thin layers containing at least either one of platinum and palladium.
    Type: Grant
    Filed: April 13, 1987
    Date of Patent: December 6, 1988
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Takashi Yamada, Masaaki Nomura, Ryoichi Yamamoto, Akira Nahara
  • Patent number: 4748592
    Abstract: In a vacuum, recording is conducted by exposing a solid surface to a neutral particle beam or an ion beam modulated with a recording signal and converged, thereby to locally develop a change in composition on the solid surface. Then, reproducing is conducted by exposing said solid surface to an electron beam, an ion beam or a neutral particle beam which has been converged, thereby to emit electrons from the solid surface, and detecting the emitted electrons to read out the change in composition. If necessary, erasing is conducted by exposing the solid surface to the same beam as used in reproducing, thereby to eliminate the change in composition.
    Type: Grant
    Filed: March 20, 1986
    Date of Patent: May 31, 1988
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Makoto Nagao, Akira Nahara, Goro Akashi
  • Patent number: 4735698
    Abstract: A method of making a magneto-optical recording medium comprises the steps of moving a rotating substrate along a first dielectric target, at least one rare earth metal target, and a second dielectric target which are disposed in this order from an upstream side toward the downstream side in an in-line sputtering apparatus, and carrying out simultaneous sputtering on the substrate in the course of the movement of the substrate by use of the first dielectric target and the rare earth metal target. Thereafter, sputtering is carried out on the substrate by use of the rare earth metal target. Then, simultaneous sputtering is carried out on the substrate by use of the rare earth metal target and the second dielectric target.
    Type: Grant
    Filed: April 3, 1987
    Date of Patent: April 5, 1988
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Masaaki Nomura, Takashi Yamada, Ryoichi Yamamoto, Akira Nahara
  • Patent number: 4717592
    Abstract: In forming a vertical magnetization type recording medium, a first soft magnetic film layer is formed on each side of a film-shaped support by vacuum deposition or sputtering at a temperature of 30.degree. C. or lower, a second soft magnetic film layer is formed on each of the first soft magnetic film layers, and a vertical magnetization film layer essentially containing Co-Cr is formed on each of the second soft magnetic film layers. The thickness of the first soft magnetic film layer on one side of the support may be made different from that of the first soft magnetic film layer on the other side so that curling of the recording medium is substantially eliminated.
    Type: Grant
    Filed: December 17, 1985
    Date of Patent: January 5, 1988
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Makoto Nagao, Fusao Yamanaka, Kunihiko Sano, Akira Nahara
  • Patent number: 4652483
    Abstract: A magnetic recording medium comprises a non-magnetic substrate, a thin ferromagnetic film layer overlaid on the substrate, and a polymer film formed by plasma polymerization. The thin ferromagnetic film layer is composed of ferromagnetic columnar grains. The polymer film is overlaid on the thin ferromagnetic film layer so as to permeate into the spaces between the ferromagnetic columnar grains, thereby improving the corrosion resistance and durability of the magnetic recording medium.
    Type: Grant
    Filed: March 14, 1984
    Date of Patent: March 24, 1987
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Yoshihiro Arai, Akira Nahara, Kiyotaka Fukino