Patents by Inventor Toshihiko Shirasagi

Toshihiko Shirasagi 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).

  • Publication number: 20120128917
    Abstract: An inorganic resist layer made of an incomplete oxide of a transition metal is formed as a film onto a substrate by a sputtering method. A single element or alloy of the transition metal, or an oxide of them is used as a target material. Oxygen or nitrogen is used as a reactive gas. Oxygen concentration of the inorganic resist layer is made different in the thickness direction by changing a reactive gas ratio or a film forming power. A master disc (for an optical disc) in which fine concave/convex patterns such as pits, grooves, and the like have been formed by exposing and developing the inorganic resist layer is formed. Since sensitivity rises with an increase in oxygen concentration, the sensitivity can be made different in the thickness direction of the inorganic resist layer and the concave/convex shapes of different depths can be formed on the same disc.
    Type: Application
    Filed: January 27, 2012
    Publication date: May 24, 2012
    Applicant: Sony Corporation
    Inventors: Toshihiko Shirasagi, Shinji Minegishi
  • Patent number: 7933186
    Abstract: A method and apparatus for manufacturing an optical disk master and an optical disk, including measuring the reflectance of laser light at each of a plurality of radius positions by applying the laser light to an optical disk master-forming substrate provided with an inorganic resist layer, the laser light having a non-recording laser power smaller than a recording sensitivity of the inorganic resist layer, producing recording power control data indicating recording laser powers in accordance with the radius positions of the optical disk master-forming substrate by using the reflectances measured, forming an exposure pattern on the inorganic resist layer by applying the laser light to the optical disk master-forming substrate on the basis of the recording power control data while the recording power is varied in accordance with the radius positions, and developing the inorganic resist layer provided with the exposure pattern so as to prepare an uneven pattern.
    Type: Grant
    Filed: April 6, 2007
    Date of Patent: April 26, 2011
    Assignee: Sony Corporation
    Inventor: Toshihiko Shirasagi
  • Publication number: 20100134892
    Abstract: In an optical device, a number of structures having higher portions or lower portions are arranged at a fine pitch equal to or shorter than a wavelength of visible light on a surface of a base. Each of the structures is arranged to form a plurality of arc track rows on the surface of the base, and to form a quasi-hexagonal lattice pattern, and the structure has an elliptical cone or truncated elliptical cone shape having a major axis in a circumferential direction of the arc tracks.
    Type: Application
    Filed: December 9, 2009
    Publication date: June 3, 2010
    Applicants: SONY CORPORATION, SONY DISC & DIGITAL SOLUTIONS INC.
    Inventors: Sohmei Endoh, Kazuya Hayashibe, Tooru Nagai, Ikuhiro Hideta, Toshihiko Shirasagi, Kimitaka Nishimura, Tadao Suzuki
  • Publication number: 20090155730
    Abstract: A method for manufacturing an information storage medium in which information is stored as a concave-convex pattern includes forming an inorganic-resist master disc by depositing on a substrate an inorganic resist layer reactive to thermal reaction associated with laser beam irradiation, recording on the inorganic-resist master disc by differentiating depths of thermal reaction portions in the inorganic resist layer by inputting information to be stored in the information storage medium and varying power of the laser beam striking the inorganic-resist master disc over at least three levels according to the input information, forming an information storage master disc having a concave-convex pattern in the inorganic resist layer by developing the recorded inorganic-resist master disc, forming a stamper to which the concave-convex pattern formed on the inorganic resist layer has been transferred on the basis of the information storage master disc, and forming the information storage medium using the stamper.
    Type: Application
    Filed: November 25, 2008
    Publication date: June 18, 2009
    Applicant: Sony Corporation
    Inventor: Toshihiko SHIRASAGI
  • Publication number: 20080265149
    Abstract: In an optical device, a number of structures having higher portions or lower portions are arranged at a fine pitch equal to or shorter than a wavelength of visible light on a surface of a base. Each of the structures is arranged to form a plurality of arc track rows on the surface of the base, and to form a quasi-hexagonal lattice pattern, and the structure has an elliptical cone or truncated elliptical cone shape having a major axis in a circumferential direction of the arc tracks.
    Type: Application
    Filed: August 21, 2007
    Publication date: October 30, 2008
    Applicants: SONY CORPORATION, SONY DISC & DIGITAL SOLUTIONS INC.
    Inventors: Sohmei Endoh, Kazuya Hayashibe, Tooru Nagai, Ikuhiro Hideta, Toshihiko Shirasagi, Kimitaka Nishimura, Tadao Suzuki
  • Publication number: 20070238055
    Abstract: A method for manufacturing an optical disk master, a method for manufacturing an optical disk, and an apparatus for manufacturing an optical disk master are provided.
    Type: Application
    Filed: April 6, 2007
    Publication date: October 11, 2007
    Applicant: SONY CORPORATION
    Inventor: Toshihiko Shirasagi
  • Publication number: 20070105055
    Abstract: An inorganic resist layer made of an incomplete oxide of a transition metal is formed as a film onto a substrate by a sputtering method. A single element or alloy of the transition metal, or an oxide of them is used as a target material. Oxygen or nitrogen is used as a reactive gas. Oxygen concentration of the inorganic resist layer is made different in the thickness direction by changing a reactive gas ratio or a film forming power. A master disc (for an optical disc) in which fine concave/convex patterns such as pits, grooves, and the like have been formed by exposing and developing the inorganic resist layer is formed. Since sensitivity rises with an increase in oxygen concentration, the sensitivity can be made different in the thickness direction of the inorganic resist layer and the concave/convex shapes of different depths can be formed on the same disc.
    Type: Application
    Filed: November 30, 2004
    Publication date: May 10, 2007
    Applicant: Sony Corporation
    Inventors: Toshihiko Shirasagi, Shinji Minegishi