Patents Assigned to HOYA GLASS DISK VIETNAM II LTD.
  • Publication number: 20210327464
    Abstract: A magnetic-disk substrate has an average value of squares of inclinations that is 0.0025 or less, and a frequency at which squares of inclinations are 0.004 or more is 15% or less, in a case where samples of inclinations on a main surface are obtained at intervals of 10 nm. The main surface is configured to receive at least a magnetic recording layer thereon. The magnetic-disk substrate includes an outer circumferential end portion and an inner circumferential end portion, and the outer circumferential end portion and the inner circumferential end portion have chamfered portions.
    Type: Application
    Filed: June 30, 2021
    Publication date: October 21, 2021
    Applicants: HOYA CORPORATION, HOYA GLASS DISK VIETNAM II LTD.
    Inventors: Masanobu ITAYA, Kinobu OSAKABE, Toshio TAKIZAWA
  • Patent number: 11081134
    Abstract: A hard disk drive includes a magnetic-disk substrate in which an average value of squares of inclinations is 0.0025 or less and a frequency at which squares of inclinations are 0.004 or more is 15% or less, in a case where samples of inclinations on a main surface are obtained at intervals of 10 nm.
    Type: Grant
    Filed: March 28, 2019
    Date of Patent: August 3, 2021
    Assignees: HOYA CORPORATION, HOYA GLASS DISK VIETNAM II LTD.
    Inventors: Masanobu Itaya, Kinobu Osakabe, Toshio Takizawa
  • Patent number: 10283156
    Abstract: A magnetic-disk glass substrate of the present invention has an average value of squares of inclinations of 0.0025 or less and a frequency at which squares of inclinations are 0.004 or more of 15% or less, in a case where samples of inclinations on a main surface are obtained at intervals of 10 nm.
    Type: Grant
    Filed: January 9, 2017
    Date of Patent: May 7, 2019
    Assignees: HOYA CORPORATION, HOYA GLASS DISK VIETNAM II LTD.
    Inventors: Masanobu Itaya, Kinobu Osakabe, Toshio Takizawa
  • Patent number: 9728217
    Abstract: A glass substrate for use as a magnetic disk for heat assisted magnetic recording can restrain the occurrence of scratches when a magnetic head is in operation. The glass substrate for the magnetic disk includes a principal face on which an arithmetic average waviness Wa of a wavelength band of 1 to 3 mm is 2.15 ? or less.
    Type: Grant
    Filed: October 31, 2013
    Date of Patent: August 8, 2017
    Assignees: HOYA GLASS DISK VIETNAM II LTD., HOYA CORPORATION
    Inventors: Masayoshi Yoshida, Masahiro Katagiri
  • Publication number: 20170186459
    Abstract: A magnetic-disk glass substrate of the present invention has an average value of squares of inclinations of 0.0025 or less and a frequency at which squares of inclinations are 0.004 or more of 15% or less, in a case where samples of inclinations on a main surface are obtained at intervals of 10 nm.
    Type: Application
    Filed: January 9, 2017
    Publication date: June 29, 2017
    Applicants: HOYA CORPORATION, HOYA GLASS DISK VIETNAM II LTD.
    Inventors: Masanobu ITAYA, Kinobu OSAKABE, Toshio TAKIZAWA
  • Patent number: 9564166
    Abstract: A magnetic-disk glass substrate of the present invention has an average value of squares of inclinations of 0.0025 or less and a frequency at which squares of inclinations are 0.004 or more of 15% or less, in a case where samples of inclinations on a main surface are obtained at intervals of 10 nm.
    Type: Grant
    Filed: June 28, 2013
    Date of Patent: February 7, 2017
    Assignees: HOYA CORPORATION, HOYA GLASS DISK VIETNAM II LTD.
    Inventors: Masanobu Itaya, Kinobu Osakabe, Toshio Takizawa
  • Publication number: 20160254018
    Abstract: It is to provide a glass substrate for a magnetic disk to be a source of a magnetic disk for heat assisted magnetic recording and a magnetic disk for heat assisted magnetic recording which can restrain the occurrence of scratches when a magnetic head is in operation. A glass substrate for a magnetic disk to be a source of a magnetic disk for heat assisted magnetic recording includes a principal face on which an arithmetic average waviness Wa of a wavelength band of 1 to 3 mm is 2.15 ? or less.
    Type: Application
    Filed: October 31, 2013
    Publication date: September 1, 2016
    Applicants: HOYA GLASS DISK VIETNAM II LTD., HOYA CORPORATION
    Inventors: Masayoshi YOSHIDA, Masahiro KATAGIRI
  • Publication number: 20150213826
    Abstract: A magnetic-disk glass substrate of the present invention has an average value of squares of inclinations of 0.0025 or less and a frequency at which squares of inclinations are 0.004 or more of 15% or less, in a case where samples of inclinations on a main surface are obtained at intervals of 10 nm.
    Type: Application
    Filed: June 28, 2013
    Publication date: July 30, 2015
    Applicants: HOYA GLASS DISK VIETNAM II LTD., HOYA CORPORATION
    Inventors: Masanobu Itaya, Kinobu Osakabe, Toshio Takizawa