Patents by Inventor Yuuichi Kokaku

Yuuichi Kokaku 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: 7147943
    Abstract: This magnetic recording medium is characterized in that in the magnetic recording medium having a magnetic layer on a non-magnetic substrate by intercalating at least an under layer, the proportion of functional groups per 100 carbon atoms in a diamond-like carbon protective layer mainly composed of carbon for protecting the magnetic layer exceeds 20%. The bonding force between the protective layer and the lubricating layer of the magnetic recording medium is increased so that under high speed rotation, a decrease in the lubricating layer is not caused so as to provide a magnetic recording apparatus having high reliability.
    Type: Grant
    Filed: May 6, 2003
    Date of Patent: December 12, 2006
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Toshinori Ono, Yuuichi Kokaku, Hiroyuki Matsumoto, Hiroshi Tani, Mitsuhiro Shoda, Tomonori Kozaki, Hiroshi Ishikawa, Toru Yatsue, Yoshinori Honda, Shigehiko Fujimaki
  • Publication number: 20060153975
    Abstract: This magnetic recording medium is characterized in that in the magnetic recording medium having a magnetic layer on a non-magnetic substrate by intercalating at least an under layer, the proportion of functional groups per 100 carbon atoms in a diamond-like carbon protective layer mainly composed of carbon for protecting the magnetic layer exceeds 20%. The bonding force between the protective layer and the lubricating layer of the magnetic recording medium is increased so that under high speed rotation, a decrease in the lubricating layer is not caused so as to provide a magnetic recording apparatus having high reliability.
    Type: Application
    Filed: March 10, 2006
    Publication date: July 13, 2006
    Inventors: Toshinori Ono, Yuuichi Kokaku, Hiroshi Ishikawa, Toru Yatsue, Yoshinori Honda, Shigehiko Fujimaki
  • Patent number: 7045175
    Abstract: A method for manufacturing a magnetic recording medium includes forming a first protective layer of first material over a magnetic film provided on a substrate. The first protective layer has a thickness of about 0.2 nm to about 2 nm. A second protective layer of second material is formed over the first protective layer by driving ions of the second material into the first protective layer. The first protective layer is configured to prevent the ions of the second material from penetrating into the magnetic film.
    Type: Grant
    Filed: February 28, 2003
    Date of Patent: May 16, 2006
    Assignee: Hitachi, Ltd.
    Inventors: Shigehiko Fujimaki, Toru Yatsue, Yuuichi Kokaku, Toshinori Ono
  • Patent number: 7037607
    Abstract: An object of the present invention is to provide a magnetic recording medium which has a sufficient impact resistance to withstand its accidental collision with a magnetic head and is neither worn away nor fractured in the CSS area by contact or friction between the magnetic recording medium and the magnetic head even if the thickness of a protective filmy layer is reduced in the data area. In order to achieve this object, a magnetic film and a protective film are formed on a substrate, and for example, the other portion of said protective film than a portion where said protective film comes into contact with a magnetic head is made of not only carbon and nitrogen but also hydrogen for increasing the hardness of said protective film.
    Type: Grant
    Filed: January 28, 2002
    Date of Patent: May 2, 2006
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Toshinori Ono, Yuuichi Kokaku, Yoshinori Honda, Hiroyuki Suzuki
  • Patent number: 6949301
    Abstract: This magnetic recording medium is characterized in that in the magnetic recording medium having a magnetic film on a non-magnetic substrate by intercalating at least an under layer, the proportion of functional groups per 100 carbon atoms in a diamond-like carbon protective coating mainly composed of carbon for protecting the magnetic film exceeds 20%. The bonding force between the protective coating layer and the lubricating layer of the magnetic recording medium is increased so that under high speed rotation, a decrease in the lubricating layer is not caused so as to provide a magnetic recording apparatus having high reliability.
    Type: Grant
    Filed: February 16, 2001
    Date of Patent: September 27, 2005
    Assignee: Hitachi Global Storage Technologies Japan, Ltd.
    Inventors: Toshinori Ono, Yuuichi Kokaku, Yoshinori Honda, Shigehiko Fujimaki, Tooru Yatsue
  • Publication number: 20050106314
    Abstract: This magnetic recording medium is characterized in that in the magnetic recording medium having a magnetic film on a non-magnetic substrate by intercalating at least an under layer, the proportion of functional groups per 100 carbon atoms in a diamond-like carbon protective coating mainly composed of carbon for protecting the magnetic film exceeds 20%. The bonding force between the protective coating layer and the lubricating layer of the magnetic recording medium is increased so that under high speed rotation, a decrease in the lubricating layer is not caused so as to provide a magnetic recording apparatus having high reliability.
    Type: Application
    Filed: October 18, 2004
    Publication date: May 19, 2005
    Inventors: Toshinori Ono, Yuuichi Kokaku, Yoshinori Honda, Shigehiko Fujimaki, Tooru Yatsue
  • Publication number: 20040166279
    Abstract: An object of the present invention is to provide a magnetic recording medium which has a sufficient impact resistance to withstand its accidental collision with a magnetic head and is neither worn away nor fractured in the CSS area by contact or friction between the magnetic recording medium and the magnetic head even if the thickness of a protective filmy layer is reduced in the data area. In order to achieve this object, a magnetic film and a protective film are formed on a substrate, and for example, the other portion of said protective film than a portion where said protective film comes into contact with a magnetic head is made of not only carbon and nitrogen but also hydrogen for increasing the hardness of said protective film.
    Type: Application
    Filed: January 28, 2002
    Publication date: August 26, 2004
    Inventors: Toshinori Ono, Yuuichi Kokaku, Yoshinori Honda, Hiroyuki Suzuki
  • Patent number: 6706363
    Abstract: A magnetic recording medium is provided in which film thickness of the DLC layer is 5 nm or less. A tangential force of the magnetic head is small. The magnetic recording medium has excellent durability to sliding property. A magnetic storage device can be realized that is capable of stable floating of the magnetic head at 10 nm or less. The magnetic recording medium has a primary coat layer, a magnetic layer, and an overcoat layer on a substrate, wherein the overcoat layer is composed of a DLC film, and in an area in which depth from the surface of the DLC film is 13 Å or less, there is formed a CN bond.
    Type: Grant
    Filed: August 14, 2001
    Date of Patent: March 16, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Yoshinori Honda, Yuuichi Kokaku, Toshinori Ono, Shigehiko Fujimaki, Hiroyuki Kataoka
  • Publication number: 20040028949
    Abstract: This magnetic recording medium is characterized in that in the magnetic recording medium having a magnetic layer on a non-magnetic substrate by intercalating at least an under layer, the proportion of functional groups per 100 carbon atoms in a diamond-like carbon protective layer mainly composed of carbon for protecting the magnetic layer exceeds 20%. The bonding force between the protective layer and the lubricating layer of the magnetic recording medium is increased so that under high speed rotation, a decrease in the lubricating layer is not caused so as to provide a magnetic recording apparatus having high reliability.
    Type: Application
    Filed: May 6, 2003
    Publication date: February 12, 2004
    Inventors: Toshinori Ono, Yuuichi Kokaku, Hiroyuki Matsumoto, Hiroshi Tani, Mitsuhiro Shoda, Tomonori Kozaki, Hiroshi Ishikawa, Toru Yatsue, Yoshinori Honda, Shigehiko Fujimaki
  • Publication number: 20030228496
    Abstract: A method for manufacturing a magnetic recording medium includes forming a first protective layer of first material over a magnetic film provided on a substrate. The first protective layer has a thickness of about 0.2 nm to about 2 nm. A second protective layer of second material is formed over the first protective layer by driving ions of the second material into the first protective layer. The first protective layer is configured to prevent the ions of the second material from penetrating into the magnetic film.
    Type: Application
    Filed: February 28, 2003
    Publication date: December 11, 2003
    Applicant: Hitachi, Inc.
    Inventors: Shigehiko Fujimaki, Toru Yatsue, Yuuichi Kokaku, Toshinori Ono
  • Patent number: 6491798
    Abstract: A magnetic recording medium includes at least a substrate, a recording layer formed of a non-magnetic underlying layer and a ferromagnetic thin film, deposited on the substrate, a sputtered carbon protective layer and a lubricant layer overlying the recording layer. The sputtered carbon protective layer is laminate layer formed by sputtering alternating first and second carbon layers, wherein a Young's modulus in a head pressing direction is twice or more larger than a Young's modulus in a head running direction. In this way, the durability of the magnetic disk can be significantly improved, and consequently, the protective layer can be made extremely thin, so that it can also contribute to an increased recording density.
    Type: Grant
    Filed: October 19, 2001
    Date of Patent: December 10, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Yuuichi Kokaku, Yoshinori Honda, Toshinori Ono
  • Publication number: 20020146532
    Abstract: There will be provided a magnetic recording medium in which film thickness of the DLC layer is 5 nm or less, a tangential force of the magnetic head is small, having excellent durability to sliding property, and there will be obtained a magnetic storage device capable of stable floating of the magnetic head at 10nm or less. There will be used a magnetic recording medium having a primary coat layer, a magnetic layer, and an overcoat layer on a substrate, wherein the overcoat layer is composed of a DLC film, and in an area in which depth from the surface of the DLC film is 13 Å or less, there is formed a CN bond.
    Type: Application
    Filed: August 14, 2001
    Publication date: October 10, 2002
    Inventors: Yoshinori Honda, Yuuichi Kokaku, Toshinori Ono, Shigehiko Fujimaki, Hiroyuki Kataoka
  • Patent number: 6403194
    Abstract: An object of the present invention is to provide a magnetic recording medium which has a sufficient impact resistance to withstand its accidental collision with a magnetic head and is neither worn away nor fractured in the CSS area by contact or friction between the magnetic recording medium and the magnetic head even if the thickness of a protective filmy layer is reduced in the data area. In order to achieve this object, a magnetic film and a protective film are formed on a substrate, and for example, the other portion of said protective film than a portion where said protective film comes into contact with a magnetic head is made of not only carbon and nitrogen but also hydrogen for increasing the hardness of said protective film.
    Type: Grant
    Filed: August 23, 1999
    Date of Patent: June 11, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Toshinori Ono, Yuuichi Kokaku, Yoshinori Honda, Hiroyuki Suzuki
  • Patent number: 6395412
    Abstract: Surface roughness of the magnetic layer and the protective layer is flatter than the surface roughness of the substrate to decrease medium noise, hereby levitation stability of the magnetic head in the ultra low region and high density recording is obtained, for magnetic recording medium and magnetic disk apparatus of high reliability.
    Type: Grant
    Filed: September 20, 1999
    Date of Patent: May 28, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Yoshinori Honda, Yuuichi Kokaku, Mitsuhiro Shoda, Toshinori Ono
  • Publication number: 20020037440
    Abstract: This magnetic recording medium is characterized in that in the magnetic recording medium having a magnetic film on a non-magnetic substrate by intercalating at least an under layer, the proportion of functional groups per 100 carbon atoms in a diamond-like carbon protective coating mainly composed of carbon for protecting the magnetic film exceeds 20%. The bonding force between the protective coating layer and the lubricating layer of the magnetic recording medium is increased so that under high speed rotation, a decrease in the lubricating layer is not caused so as to provide a magnetic recording apparatus having high reliability.
    Type: Application
    Filed: February 16, 2001
    Publication date: March 28, 2002
    Inventors: Toshinori Ono, Yuuichi Kokaku, Yoshinori Honda, Shigehiko Fujimaki, Tooru Yatsue
  • Publication number: 20020025451
    Abstract: A magnetic recording medium includes at least a substrate, a recording layer formed of a non-magnetic underlying layer and a ferromagnetic thin film, deposited on the substrate, and a protective layer and a lubricant layer overlying the recording layer, a laminate layer is used as the protective layer, wherein a Young's modulus in a head pressing direction is twice or more larger than a Young's modulus in a head running direction.
    Type: Application
    Filed: October 19, 2001
    Publication date: February 28, 2002
    Applicant: Hitachi, Ltd.
    Inventors: Yuuichi Kokaku, Yoshinori Honda, Toshinori Ono
  • Patent number: 6329037
    Abstract: A magnetic recording medium includes at least a substrate, a recording layer formed of a non-magnetic underlying layer and a ferromagnetic thin film, deposited on the substrate, and a protective layer and a lubricant layer overlying the recording layer, a laminate layer is used as the protective layer, wherein a Young's modulus in a head pressing direction is twice or more larger than a Young's modulus in a head running direction. In this way, the durability of the magnetic disk can be significantly improved, and consequently, the protective layer can be made extremely thin, so that it can also contribute to an increased recording density.
    Type: Grant
    Filed: April 14, 2000
    Date of Patent: December 11, 2001
    Assignee: Hitachi, Ltd.
    Inventors: Yuuichi Kokaku, Yoshinori Honda, Toshinori Ono
  • Patent number: 4863557
    Abstract: Disclosed herein are a pattern forming process, particularly the one by lithography for fine fabrication, and a thin-film magnetic head formed by said process. The present invention provides a process for accurately fabricating a substrate having a stepped surface by dry etching, using as the mask a resist film formed by plasma polymerization. Plasma polymerization forms a uniform photosensitive resist film on a stepped surface, and the resist film can be used as the mask for the ion milling of the substrate.
    Type: Grant
    Filed: May 25, 1988
    Date of Patent: September 5, 1989
    Inventors: Yuuichi Kokaku, Makoto Kitou
  • Patent number: 4713288
    Abstract: Disclosed is a magnetic recording medium in which a magnetic layer of a ferromagnetic material, a layer of an organic material and a layer of carbon are formed on a substrate in this order.The magnetic recording medium has the benefit of remarkably extended life time because peeling and removing of the carbon protective layer can be prevented so that carbon can exerts its own lubricating action during the sliding contact of the magnetic recording medium with a magnetic head.
    Type: Grant
    Filed: June 4, 1986
    Date of Patent: December 15, 1987
    Assignee: Hitachi, Ltd.
    Inventors: Yuuichi Kokaku, Makoto Kitoh, Yoshinori Honda
  • Patent number: 4629547
    Abstract: A protective film having a very low coefficient of friction, a good wear resistance, a good adhesion, and prolonged lubricating and moisture-resistant properties is formed on a substrate by sputtering of a target consisting of at least one of organic polymers and at least one of boron compounds.
    Type: Grant
    Filed: November 15, 1984
    Date of Patent: December 16, 1986
    Assignee: Hitachi, Ltd.
    Inventors: Yoshinori Honda, Makoto Kitoo, Yuuichi Kokaku