Patents by Inventor Ryoichi Shiratori

Ryoichi Shiratori 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).

  • Ring zonal phase correction lens and optical system and optical head device
    Patent number: 7236313
    Abstract: A ring zonal phase correction lens made of resin is provided with a refraction face structurally formed on at least one of a first lens face and a second lens face. The refraction face includes three or more ring zonal shaped refraction curved surfaces which are formed to be adjacent to each other through step portions formed in an optical axis direction for correcting a phase of a laser beam emitted from a laser by respective ring zonal shaped refraction curved surfaces. The step portion is formed such that a lens thickness of an outer ring zonal shaped refraction curved surface becomes thicker than that of an inner ring zonal shaped refraction curved surface and the step portion is formed at a half or more outer area of an effective radius of the refraction face.
    Type: Grant
    Filed: October 5, 2005
    Date of Patent: June 26, 2007
    Assignee: Nidec Nissin Corporation
    Inventors: Tetsuro Okamura, Ryoichi Shiratori
  • Ring zonal phase correction lens and optical system and optical head device
    Publication number: 20060077568
    Abstract: A ring zonal phase correction lens made of resin is provided with a refraction face structurally formed on at least one of a first lens face and a second lens face. The refraction face includes three or more ring zonal shaped refraction curved surfaces which are formed to be adjacent to each other through step portions formed in an optical axis direction for correcting a phase of a laser beam emitted from a laser by respective ring zonal shaped refraction curved surfaces. The step portion is formed such that a lens thickness of an outer ring zonal shaped refraction curved surface becomes thicker than that of an inner ring zonal shaped refraction curved surface and the step portion is formed at a half or more outer area of an effective radius of the refraction face.
    Type: Application
    Filed: October 5, 2005
    Publication date: April 13, 2006
    Inventors: Tetsuro Okamura, Ryoichi Shiratori