Patents by Inventor Kazuko Shigematsu

Kazuko Shigematsu 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: 6947367
    Abstract: A low-profile optical disk device which performs recording and reproducing using a plurality of laser light sources with different wavelengths, without thug need for additional components. It is used as a DVD-Ram, CD-R or the like. It comprises a plurality of neighboring laser light sources with different wavelengths: a beam-shaping prism for expanding the width of laser beams in a direction in which the plural laser light sources are arranged; and a focus lens which forms an optical spot on an optical disk, where laser light sources with longer wavelengths are positioned closer to an extension line of a refracted beam created by the beam-shaping prism. The above arrangement enables correction of optical spot coma aberrations caused by a laser light source positioned out of the optical axis of the focus lens, thereby realizing a low-profile optical disk device with high optical performance.
    Type: Grant
    Filed: March 2, 2001
    Date of Patent: September 20, 2005
    Assignee: Hitachi, Ltd.
    Inventors: Shigeru Nakamura, Kouji Arikawa, Kazuko Shigematsu