Patents by Inventor Sigeru Sano

Sigeru Sano 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: 6303205
    Abstract: A magnetic disk includes a substrate, a magnetic layer, and a protective layer. At least one region of a surface of the magnetic disk has protrusions. A height of each of the protrusions is not less than 5 nm and not greater than 40 nm, and is within ±30% of an average height of the protrusions. A density of the protrusions is not less than 200/mm2 and is not greater than 250,000/mm2. A width of a surface of each of the protrusions in a radial direction of the magnetic disk is not less than 0.1 &mgr;m and is not greater than 10 &mgr;m. The protrusions are discrete protrusions aligned in a spiral direction of the magnetic disk at a predetermined spacing in the radial direction of the magnetic disk. The at least one region of the surface of the magnetic disk includes flat areas between the protrusions.
    Type: Grant
    Filed: May 18, 1999
    Date of Patent: October 16, 2001
    Assignee: Hitachi, Ltd.
    Inventors: Hideaki Tanaka, Kenichi Gomi, Yoshihiko Miyake, Sigeru Sano, Youichi Inomata, Hiroshi Yashiki, Yoshiki Kato, Masaki Ohura
  • Patent number: 5930073
    Abstract: There is provided a magnetic disk apparatus comprising: at least one magnetic disk having a magnetic layer and a surface protective layer on a substrate; a magnetic head which faces the magnetic disk in a rotating state with a micro gap and is supported by a slider; rotating means for rotating the magnetic disk; and a actuator for moving and positioning the magnetic head to a predetermined position on the magnetic disk, wherein a plurality of protrusions each having a flat surface are formed in at least a region on the surface of the magnetic disk where a contact start/stop operation can be executed. According to the above magnetic disk apparatus, since the frictional force between the disk and the head is small and the flying height of the head can be reduced and the good floating stability is obtained, so that the excellent recording and reproducing characteristics are derived.
    Type: Grant
    Filed: April 1, 1996
    Date of Patent: July 27, 1999
    Assignee: Hitachi, Ltd.
    Inventors: Hideaki Tanaka, Kenichi Gomi, Yoshihiko Miyake, Sigeru Sano, Youichi Inomata, Hiroshi Yashiki, Yoshiki Kato, Masaki Ohura
  • Patent number: 5504646
    Abstract: There is provided a magnetic disk apparatus comprising: at least one magnetic disk having a magnetic layer and a surface protective layer on a substrate; a magnetic head which faces the magnetic disk in a rotating state with a micro gap and is supported by a slider; rotating means for rotating the magnetic disk; and a actuator for moving and positioning the magnetic head to a predetermined position on the magnetic disk, wherein a plurality of protrusions each having a flat surface are formed in at least a region on the surface of the magnetic disk where a contact start/stop operation can be executed. According to the above magnetic disk apparatus, since the frictional force between the disk and the head is small and the flying height of the head can be reduced and the good floating stability is obtained, so that the excellent recording and reproducing characteristics are derived.
    Type: Grant
    Filed: June 18, 1993
    Date of Patent: April 2, 1996
    Assignee: Hitachi, Ltd.
    Inventors: Hideaki Tanaka, Kenichi Gomi, Yoshihiko Miyake, Sigeru Sano, Youichi Inomata, Hiroshi Yashiki, Yoshiki Kato, Masaki Ohura