Patents by Inventor Yoshiharu YUASA

Yoshiharu YUASA 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: 20230012479
    Abstract: A variable magnification optical system (ZL) comprises a preceding lens group (GA) having negative refractive power and a succeeding lens group (GB) having positive refractive power, which are arranged in order from the object side along an optical axis. The succeeding lens group (GB) has a focusing group (GF) and an image-side group (GC) disposed closer to the image side than the focusing group (GF), the focusing group (GF) moves to the image side along the optical axis from focusing on an object at infinity to focusing on a close-distance object, and the following conditional expression is satisfied. 1.80<fF/fBaw FNow<3.40 where fF is the focal length of the focusing group (GF), fBaw is the focal length in the wide-angle end state of an image-side lens group (GBa) composed of lenses disposed on the image side from the focusing group (GF), and FNow is the F-number of the variable magnification optical system (ZL) in the wide-angle end state.
    Type: Application
    Filed: December 2, 2020
    Publication date: January 19, 2023
    Inventors: Fumiaki OHTAKE, Azuna NONAKA, Yoshiharu YUASA, Takeshi UMEDA