Patents by Inventor Sachiko Ryu

Sachiko Ryu 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).

  • Wide-angle lens system
    Patent number: 7209300
    Abstract: A wide-angle lens system includes a positive front lens group, a diaphragm, and a positive rear lens group. The front lens group includes a negative first-sub-lens group and a positive second-sub-lens group. The negative first-sub-lens group includes a negative lens element, a positive lens element, and a negative lens element. The front lens group satisfies the following conditions: 0.5<f/|f1a|<0.75??(1) 0.5<|f1a|/f1b<1.0??(2) 0.35<f/f1bi<0.6??(3) wherein f: the focal length of the entire lens system; f1a: the focal length of the negative first-sub-lens group; f1b: the focal length of the positive second-sub-lens group; f1bi: the focal length of the most image-side surface of the positive second-sub-lens group; r1bi: the radius of curvature of the most image-side surface of the positive second-sub-lens group; and N1bi: a refractive index of the most image-side lens element of the positive second-sub-lens group.
    Type: Grant
    Filed: December 14, 2005
    Date of Patent: April 24, 2007
    Assignee: Pentax Corporation
    Inventors: Sachiko Ryu, Takayuki Ito
  • Wide-angle lens system
    Publication number: 20060126192
    Abstract: A wide-angle lens system includes a positive front lens group, a diaphragm, and a positive rear lens group. The front lens group includes a negative first-sub-lens group and a positive second-sub-lens group. The negative first-sub-lens group includes a negative lens element, a positive lens element, and a negative lens element. The front lens group satisfies the following conditions: 0.5<f/|f1a|<0.75 . . . (1) 0.5<|f1a|/f1b<1.0 . . . (2) 0.35<f/f1bi<0.6 . . . (3) wherein f: the focal length of the entire lens system; f1a: the focal length of the negative first-sub-lens group ; f1b:the focal length of the positive second-sub-lens group ; f1bi: the focal length of the most image-side surface of the positive second-sub-lens group; r1bi: the radius of curvature of the most image-side surface of the positive second-sub-lens group; and N1bi: a refractive index of the most image-side lens element of the positive second-sub-lens group.
    Type: Application
    Filed: December 14, 2005
    Publication date: June 15, 2006
    Applicant: PENTAX Corporation
    Inventors: Sachiko Ryu, Takayuki Ito