Patents by Inventor Masami Arisaka

Masami Arisaka 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: 5691850
    Abstract: An eyepiece has an apparent visual angle of 40.degree. or more, and is constituted by, in the following order from the eyepoint side, a first lens group including a cemented lens of negative and positive lens components and having a positive refractive power, a second lens group including a single positive lens component, a third lens group including a cemented lens of positive and negative lens components and having a positive refracting power, and a fourth lens group including a single negative lens component. At least one surface in these lens groups is an aspherical surface, and the fourth-order aspherical surface coefficient of the aspherical surface satisfies .vertline.C.sub.4 .vertline..ltoreq.1.times.10.sup.-3.
    Type: Grant
    Filed: March 17, 1995
    Date of Patent: November 25, 1997
    Assignee: Nikon Corporation
    Inventor: Masami Arisaka