Patents by Inventor Yukitugu Nakamura

Yukitugu Nakamura 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: 4710003
    Abstract: In a cornea shape measuring apparatus wherein a chart for measurement is projected onto the cornea of an eye to be examined and the shape of the corneal reflection image thereof is detected through a measuring optical system to thereby measure the shape of the cornea, there is provided an observation optical system for enabling the corneal reflection image to be always observed. The magnification of the observation optical system is made smaller than the magnification of the measuring optical system and the fore eye portion and the corneal reflection image are always observable.
    Type: Grant
    Filed: February 21, 1986
    Date of Patent: December 1, 1987
    Assignee: Canon Kabushiki Kaisha
    Inventors: Takashi Masuda, Yukitugu Nakamura, Kyoji Sekiguchi
  • Patent number: 4666269
    Abstract: An ophthalmologic apparatus including an illuminating light source, an annular index, and an optical system for projecting the index from an infinite distance to a cornea of an eye to be examined, in which the index is formed integrally with the projecting optical system.
    Type: Grant
    Filed: November 25, 1985
    Date of Patent: May 19, 1987
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yukitugu Nakamura, Kyoji Sekiguchi, Takashi Masuda
  • Patent number: 4660946
    Abstract: A method and apparatus in which a predetermined index is projected onto the cornea of an eye to be examined and the shape of the cornea determining the refractive power, the degree of astigmatism, the direction of astigmatic axis, etc. of the cornea is measured from the general elliptical shape of the image of the index reflected by the cornea. Independently of the center of the ellipse, arbitrary position coordinates of at least five points of the image reflected by the cornea are detected, whereby the elliptical shape is calculated without enhancing the alignment accuracy in a plane perpendicular to the optical axis. The image reflected by the cornea may be electrically detected by position detects such as CCDs, whereby automation of the measurement is provided, coupled with the later signal processing. A strobo light is used for the projection of the index.
    Type: Grant
    Filed: May 14, 1985
    Date of Patent: April 28, 1987
    Assignee: Canon Kabushiki Kaisha
    Inventors: Yukitugu Nakamura, Takashi Masuda, Kyoji Sekiguchi