Patents by Inventor Mikio Murai

Mikio Murai 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: 6303227
    Abstract: A lubricant composition having excellent lubricity and comprising at least one compound selected among fluorine compounds each having a perfluoroalkyl or perfluoroether group and an alkyl or alkenyl group in the molecule and at least one compound selected among fluorine compounds each having a perfluoropolyether group in the molecule; and a magnetic recording medium excellent in running durability and still durability and comprising a nonmagnetic substrate (1) and, formed thereon in this order, a ferromagnetic thin metal film (2), a carbon film (3), and a lubricant layer (4), wherein the lubricant layer (4) contains the lubricant composition.
    Type: Grant
    Filed: January 14, 2000
    Date of Patent: October 16, 2001
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Kenji Kuwahara, Yukikazu Ohchi, Tetuo Fuchi, Mikio Murai
  • Patent number: 5798135
    Abstract: A ferromagnetic metal thin film recording medium having a nonmagnetic substrate, a ferromagnetic metal thin film formed on the nonmagnetic substrate, a dry etched layer which is formed in a surface layer of the ferromagnetic metal thin film and contains oxygen atoms in a higher concentration than the remaining part of the ferromagnetic metal thin film, a hard carbonaceous film formed on the dry etched layer of the ferromagnetic metal thin film, a lubricant layer formed on said hard carbonaceous film, and optionally a modified layer which is formed on the hard carbonaceous film and has a thickness of less than 3 nm, and comprises carbon, nitrogen and oxygen atoms with an atomic ratio of nitrogen to carbon being at least 0.8%, which recording medium has improved running stability, durability and weatherability while maintaining electromagnetic conversion characteristics.
    Type: Grant
    Filed: September 30, 1996
    Date of Patent: August 25, 1998
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hideyuki Ueda, Hiroshi Seki, Kenji Kuwahara, Mikio Murai, Kiyosi Takahasi, Masaru Odagiri, Sadayuki Okazaki
  • Patent number: 5776602
    Abstract: A magnetic recording medium of the present invention includes: a non-magnetic substrate; a ferromagnetic thin metal layer formed on the non-magnetic substrate; and a carbon layer and a lubricant layer in contact with the carbon layer, which is formed above the ferromagnetic thin metal layer so that the lubricant layer is an outermost layer, wherein the carbon layer contains nitrogen atoms, a Raman spectrum of the carbon layer has a peak A in the range of about 1310 to about 1410 cm.sup.-1 and a peak B in the range of about 1520 to about 1570 cm.sup.-1, and a ratio of integrated intensities of the peak A to the peak B is in the range of about 1.2 to about 2.0.
    Type: Grant
    Filed: October 23, 1995
    Date of Patent: July 7, 1998
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hideyuki Ueda, Kenji Kuwahara, Hiroshi Seki, Sadayuki Okazaki, Masaru Odagiri, Kiyoshi Takahashi, Mikio Murai
  • Patent number: 5670107
    Abstract: A magnetic recording medium produced by treating a magnetic recording medium which comprises a non-magnetic substrate and a magnetic layer formed on said substrate in an atmosphere kept at a temperature of at least 50.degree. C., with applying a tension of 1 gf. or less per 10 mm width to said magnetic recording medium in a treating time which is in a range on or above a line having a slope of at least 5000 in terms of .DELTA.ln(L)/.DELTA.(1/T) and passing a point of 0.5 second at 100.degree. C., when ln(L) is Arrhenius plotted against an inverse of an absolute temperature T (1/T), which medium has suppressed change of magnetic properties with time and improved corrosion resistance.
    Type: Grant
    Filed: November 8, 1995
    Date of Patent: September 23, 1997
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Kenji Kuwahara, Kiyosi Takahasi, Hideyuki Ueda, Noriyasu Echigo, Mikio Murai, Masaru Odagiri
  • Patent number: 5637393
    Abstract: A magnetic recording medium comprising a non-magnetic substrate, a ferromagnetic thin film on the non-magnetic substrate, a hard carbon film on the ferromagnetic thin film, a modified layer of which atomic ratio of nitrogen/carbon is 0.8% or more, and of which thickness is less than 3 nm on the hard carbon film, and a lubricant layer on the modified layer, has excellent electromagnetic conversion characteristic, running stability, durability, and weatherability.
    Type: Grant
    Filed: July 23, 1993
    Date of Patent: June 10, 1997
    Assignee: Matsuhita Electric Industrial Co., Ltd.
    Inventors: Hideyuki Ueda, Kenji Kuwahara, Hiroshi Seki, Kiyoshi Takahashi, Masaru Odagiri, Mikio Murai, Yukikazu Ohchi
  • Patent number: 5591481
    Abstract: A protection film and a lubricant layer of monomers are formed successively on a ferromagnetic metal thin film formed on a nonmagnetic substrate or on a base of sliding member. Then, the lubricant layer is irradiated with radicals or atomic gas in the plasma discharge or with an electron beam to form graft polymers in the lubricant layer, and the protection film and the lubricant layer are bonded chemically. Thus, the reliability of a magnetic recording medium and a sliding member can be improved.
    Type: Grant
    Filed: September 27, 1995
    Date of Patent: January 7, 1997
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Kiyoshi Takahashi, Mikio Murai, Masaru Odagiri, Hideyuki Ueda
  • Patent number: 5589263
    Abstract: A ferromagnetic metal thin film recording medium having a nonmagnetic substrate, a ferromagnetic metal thin film formed on the nonmagnetic substrate, a dry etched layer which is formed in a surface layer of the ferromagnetic metal thin film and contains oxygen atoms in a higher concentration than the remaining part of the ferromagnetic metal thin film, a hard carbonaceous film formed on the dry etched layer of the ferromagnetic metal thin film, a lubricant layer formed on said hard carbonaceous film, and optionally a modified layer which is formed on the hard carbonaceous film and has a thickness of less than 3 nm, and comprises carbon, nitrogen and oxygen atoms with an atomic ratio of nitrogen to carbon being at least 0.8%, which recording medium has improved running stability, durability and weatherability while maintaining electromagnetic conversion characteristics.
    Type: Grant
    Filed: December 28, 1994
    Date of Patent: December 31, 1996
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hideyuki Ueda, Hiroshi Seki, Kenji Kuwahara, Mikio Murai, Kiyosi Takahasi, Masaru Odagiri, Sadayuki Okazaki
  • Patent number: 5540957
    Abstract: A magnetic recording media comprising a non-magnetic substrate, a ferromagnetic thin film on the non-magnetic substrate, a hard carbon film on the ferromagnetic thin film, a modified layer of which atomic ratio of nitrogen/carbon is 0.8% or more, and of which thickness is less than 3 nm on the hard carbon film, and a lubricant layer on the modified layer, has excellent electromagnetic conversion characteristic, running stability, durability, and weatherability.
    Type: Grant
    Filed: June 7, 1995
    Date of Patent: July 30, 1996
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hideyuki Ueda, Kenji Kuwahara, Hiroshi Seki, Kiyoshi Takahashi, Masaru Odagiri, Mikio Murai, Yukikazu Ohchi
  • Patent number: 5496595
    Abstract: A magnetic recording medium comprising a back coating layer formed on a surface reverse to a magnetic layer and a carbonaceous film which is formed on the back coating layer and contains fluorine atoms and silicon atoms and/or nitrogen atoms and in which a concentration of fluorine atoms decreases in a depth direction from a surface of the carbonaceous film, while a concentration of the silicon and/or nitrogen atoms increases in the depth direction from the surface of the carbonaceous film, which recording medium has improved running stability, durability and weatherability while electromagnetic conversion characteristics are maintained.
    Type: Grant
    Filed: October 19, 1994
    Date of Patent: March 5, 1996
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hideyuki Ueda, Kenji Kuwahara, Hiroshi Seki, Kiyosi Takahasi, Masaru Odagiri, Mikio Murai
  • Patent number: 5494742
    Abstract: A magnetic recording medium comprising a non-magnetic substrate, a ferromagnetic metal film formed on said non-magnetic substrate, a carbon film which is formed on said ferromagnetic metal film and in which a concentration of at least one element selected from the group consisting of silicon, phosphorus, sulfur, tin and indium is or concentrations of boron and at least one element selected from the group consisting of tin and indium are decreased in a depth direction from the surface of said carbon film, and a lubricant layer formed on said carbon film, which medium has improved running durability and corrosion resistance.
    Type: Grant
    Filed: April 12, 1994
    Date of Patent: February 27, 1996
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hiroshi Seki, Kenji Kuwahara, Hideyuki Ueda, Kiyosi Takahasi, Masaru Odagiri, Mikio Murai
  • Patent number: 5451427
    Abstract: With the use of a novel method in which after a magnetic recording medium carrying a ferromagnetic metal thin film is heated, a protective layer is developed on the ferromagnetic metal thin film by a known plasma CVD technique while an out gas from the magnetic recording medium being eliminated by absorption, another method in which a ferromagnetic metal thin film and a protective layer are formed in succession within a vacuum chamber, or a further method in which after a non-magnetic substrate is heated, a ferromagnetic metal thin film and a protective layer are formed in succession within a vacuum chamber while an out gas from the non-magnetic substrate and the ferromagnetic metal thin film being eliminated by absorption, the atomic ratio of the hydroxyl group to a primary component metal element contained in the ferromagnetic metal thin film can be decreased at the interface between the ferromagnetic metal thin film and the protective layer.
    Type: Grant
    Filed: April 16, 1993
    Date of Patent: September 19, 1995
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Kiyoshi Takahashi, Mikio Murai, Masaru Odagiri
  • Patent number: 5443888
    Abstract: In making a magnetic recording medium, a diamond-like carbon film is formed stably with high product efficiency such as 200 .ANG./sec, without occurrence of irregular discharge, and improved still durability and reduced head contamination are achieved by utilizing a.c. plasma discharge or a.c. plasma discharge superimposed by d.c. power and the lubricant film.
    Type: Grant
    Filed: December 28, 1993
    Date of Patent: August 22, 1995
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Mikio Murai, Kiyoshi Takahashi, Masaru Odagiri, Yoshiaki Kai, Takashi Suzuki, Toshiaki Kunieda
  • Patent number: 5364690
    Abstract: A magnetic recording medium comprising: a non-magnetic substrate; a ferromagnetic metal thin film provided on the non-magnetic substrate; a filmlike first carbon layer provided on the ferromagnetic metal thin film; and a hard and amorphous second carbon layer provided on the first carbon layer; the first and second carbon layers having first and second Raman spectra based on Raman spectrophotometry, respectively; assuming that when each of the first and second Raman spectra is decomposed into a first band of Gaussian function having a peak in the vicinity of 1380 cm.sup.-1 and a second band of Gaussian function having a peak in the vicinity of 1550 cm.sup.-1 in X-Y rectangular coordinates with an X-axis expressed in cm.sup.
    Type: Grant
    Filed: October 22, 1992
    Date of Patent: November 15, 1994
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Kiyoshi Takahashi, Mikio Murai, Masaru Odagiri, Hideyuki Ueda, Yukikazu Ohchi, Tatsuya Hiwatashi
  • Patent number: 5328737
    Abstract: A method of forming a film on a substrate by plasma CVD, comprising the steps of: providing a discharge tube in a vacuum chamber; providing a partition wall around the discharge tube; evacuating space between the discharge tube and the partition wall to vacuum; providing the substrate at a position confronting the discharge tube; and effecting plasma discharge in the discharge tube.
    Type: Grant
    Filed: March 29, 1993
    Date of Patent: July 12, 1994
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Kiyoshi Takahashi, Mikio Murai, Masaru Odagiri, Hideyuki Ueda, Yukikazu Ohchi, Tatsuya Hiwatashi
  • Patent number: 5322716
    Abstract: A method of producing a magnetic recording medium comprises the steps of heating in vacuum a magnetic recording medium produced by forming a ferromagnetic metal-film-type recording medium onto a non-magnetic substrate and of forming, immediately after heating, a protective layer on the magnetic recording medium by a plasma CVD method. A production apparatus for carrying out this method comprises a feeding apparatus for feeding a magnetic recording medium with a ferromagnetic thin film formed on a non-magnetic substrate, a plasma CVD apparatus, disposed in the path of this feeding apparatus, for forming a protective layer, and a heating apparatus disposed just before this plasma CVD apparatus in the feeding path.
    Type: Grant
    Filed: December 9, 1992
    Date of Patent: June 21, 1994
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Kiyoshi Takahashi, Mikio Murai, Masaru Odagiri
  • Patent number: 5302424
    Abstract: In plasma discharge to form a film on a magnetic tape of the like in a plasma CVD process, a hollow electrode 12 is arranged in a discharge tube 8 or arranged opposed to another electrode 34. A non-polymerizable gas is blown out from the inside of the hollow electrode 12 made from a sintered alloy, and impurities do not adhere to the electrode. Then, small traces of discharge are not generated on the magnetic tape and impurities do not contaminate the magnetic tape, so that a uniform thin film of high quality is manufactured at a high rate in an industrial scale.
    Type: Grant
    Filed: July 14, 1992
    Date of Patent: April 12, 1994
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Mikio Murai, Kiyoshi Takahashi, Masaru Odagiri, Hideyuki Ueda
  • Patent number: 5182132
    Abstract: In making a magnetic recording medium, a diamond-like carbon film is formed stably with high product efficiency such as 200 .ANG./sec, without occurrence of irregular discharge, and improved still durability and reduced head contamination are achieved by utilizing a.c. plasma discharge or a.c. plasma discharge superimposed by d.c. power and the lubricant film.
    Type: Grant
    Filed: December 3, 1990
    Date of Patent: January 26, 1993
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Mikio Murai, Kiyoshi Takahashi, Masaru Odagiri, Yoshiaki Kai, Takashi Suzuki, Toshiaki Kunieda
  • Patent number: 5137784
    Abstract: A magnetic record medium comprises(A) a nonmagnetic substrate,(B) a layer consisting essentially of a ferromagnetic metal on at least one side of the substrate,(C) a layer containing carbon on the layer of (B),(D) a layer comprising a primary or secondary organic amine containing at least one substituent having a fluorinated hydrocarbon group at the end of the substituent on the layer of (C), and(E) a layer comprising at least one lubricant having a plurality or fully fluorinated hydrocarbon group on one end of the molecule and a functional group selected from the group consisting of --OH, --SH, --COOH, --COSH and --CONH.sub.2 on the other end of the molecule on the layer of (D).
    Type: Grant
    Filed: March 8, 1990
    Date of Patent: August 11, 1992
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Takashi Suzuki, Yoshiaki Kai, Mikio Murai, Kiyoshi Takahashi, Takatoshi Minoda, Hidetoshi Matsumoto
  • Patent number: 5110676
    Abstract: A magnetic metallic thin film type of recording medium has particles of predetermined size uniformly distributed over a surface of a base layer, with a magnetic metallic thin film formed over these. A diamond-state carbon protective film, a carbon protective layer, e.g. of graphite, and a layer of lubricative material are successively formed over the metallic thin film, to provide lubrication and protection. As a result of surface contour modification resulting from the protrusions formed by the particles on the base layer, the contact area between the head and the recording medium is reduced, and this together with the multiple protective layers provides greatly increased durability by comparison with prior art configurations.
    Type: Grant
    Filed: July 9, 1990
    Date of Patent: May 5, 1992
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Mikio Murai, Kiyoshi Takahashi, Masaru Odagiri
  • Patent number: 5104685
    Abstract: A method of producing a magnetic recording medium has the steps of forming a ferromagnetic metallic film layer on a non-magnetic substrate, forming, by a plasma CVD process, a protective layer on the ferromagnetic metallic film layer, and forming an oxidation layer on the protective layer by a process conducted in a vacuum atmosphere. An apparatus is disclosed for carrying out this method has a plasma CVD system for forming a ferromagnetic metallic film layer on a non-magnetic substrate, a feeding device including a plurality of rollers and for feeding the substrate carrying the ferromagnetic metal film layer in a predetermined direction, a processing device disposed at a position corresponding to one of the rollers and capable of forming a protective layer on the ferromagnetic metallic film layer, and a vacuum processing device capable of forming an oxidation layer and disposed downstream of the plasma CVD system as viewed in the direction of feed of the substrate effected by the feeding device.
    Type: Grant
    Filed: September 19, 1991
    Date of Patent: April 14, 1992
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Kiyoshi Takahashi, Mikio Murai, Masaru Odagiri