Patents by Inventor Kazuhiko Ohnuma

Kazuhiko Ohnuma 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: 7360897
    Abstract: A fundus examination apparatus includes an illumination optical system (20), which illuminates a fundus by fundus illumination light, an imaging optical system (21), which photographs a fundus image based on a polarization property of reflected illumination light, and a picture signal processing device, which processes a signal output from the imaging optical system; and the imaging optical system includes a phase plate array (42) that a plurality of unit constitutional plates (U1) is arranged in a matrix in a plane; each of the unit constitutional plates comprising four or more micro phase plates (44a-44d), a polarizer (43), which polarizes the reflected illumination light passing through the phase plate array (42) into a predetermined polarization direction, and an image pickup device (5a) that a plurality of constitutional units (U2) is arranged in a matrix in a plane; each of the constitutional units comprising four or more pixels (Ga-Gd).
    Type: Grant
    Filed: January 24, 2006
    Date of Patent: April 22, 2008
    Assignee: Kabushiki Kaisha Topcon
    Inventors: Hisao Kikuta, Kazuhiko Ohnuma, Yasufumi Fukuma, Takashi Shioiri, Hidetaka Aeba
  • Publication number: 20060164598
    Abstract: A fundus examination apparatus includes an illumination optical system (20), which illuminates a fundus by fundus illumination light, an imaging optical system (21), which photographs a fundus image based on a polarization property of reflected illumination light, and a picture signal processing device, which processes a signal output from the imaging optical system; and the imaging optical system includes a phase plate array (42) that a plurality of unit constitutional plates (U1) is arranged in a matrix in a plane; each of the unit constitutional plates comprising four or more micro phase plates (44a-44d), a polarizer (43), which polarizes the reflected illumination light passing through the phase plate array (42) into a predetermined polarization direction, and an image pickup device (5a) that a plurality of constitutional units (U2) is arranged in a matrix in a plane; each of the constitutional units comprising four or more pixels (Ga-Gd).
    Type: Application
    Filed: January 24, 2006
    Publication date: July 27, 2006
    Applicant: KABUSHIKI KAISHA TOPCON
    Inventors: Hisao Kikuta, Kazuhiko Ohnuma, Yasufumi Fukuma, Takashi Shioiri, Hidetaka Aeba
  • Patent number: 6814441
    Abstract: Disclosed are an apparatus for measurement of a polarized distribution, a polarizing filter for use of the apparatus and a polarizing filter assembly. The apparatus for measurement of polarized distribution comprises an illuminating optical system for illuminating a subject to be examined by circularly polarized detecting light, and an image receiving optical system for receiving detected light from said subject illuminated by said circularly polarized detecting light. The image receiving optical system includes a CCD element having an imaging provided integrally with a polarizing filter. The polarizing filter is composed of repetitions of unit platelets comprising polarizing micro-plates for decomposing the detecting light into first linearly polarized light components which are mutually perpendicular and polarizing micro-plates for decomposing the detecting light into second linearly polarized light components in a direction of crossing to the first linearly polarized light components.
    Type: Grant
    Filed: January 7, 2003
    Date of Patent: November 9, 2004
    Assignee: Kabushiki Kaisha TOPCON
    Inventors: Kazuhiko Ohnuma, Yasufumi Fukuma, Hidetaka Aeba
  • Publication number: 20030095233
    Abstract: Disclosed are an apparatus for measurement of a polarized distribution, a polarizing filter for use of the apparatus and a polarizing filter assembly.
    Type: Application
    Filed: January 7, 2003
    Publication date: May 22, 2003
    Applicant: Kabushiki Kaisha TOPCON
    Inventors: Kazuhiko Ohnuma, Yasufumi Fukuma, Hidetaka Aeba
  • Patent number: 6540357
    Abstract: A glaucoma diagnosis apparatus for determining thickness of nerve fiber layers. The apparatus includes an illuminating optical system for illuminating the ocular fundus of an eye to be examined with circularly polarized illuminating light and an imaging optical system including a CCD camera for photographing the image of an ocular fundus based on the reflected illuminating light from the ocular fundus and has a polarizing filter provided integrally with the imaging surface of the CCD camera. The filter includes repetitions of a unit platelet having a couple of polarizing microplates which transmit those linearly polarized light components crossing with each other out of the reflected illuminating light and adjacent polarizing microplates which transmit linearly polarized light components in direction crossing with both of the above/mentioned linearly polarized light components of the reflected illuminating light.
    Type: Grant
    Filed: November 20, 2000
    Date of Patent: April 1, 2003
    Assignee: Kabushiki Kaisha Topcon
    Inventors: Kazuhiko Ohnuma, Yasufumi Fukuma, Hidetaka Aeba
  • Patent number: 6409342
    Abstract: A glaucoma diagnosis apparatus capable of minimizing the difficulty of early glaucoma diagnosis caused by the illumination irregularities of the fundus is provided. For each part of the fundus image FB photographed by a color fundus camera Q, the G-component image data corresponding to the G-component reflected light intensity or the B-component image data corresponding to the B-component reflected light intensity is divided by the sum of the G-component image data, the B-component image data and also the R-component image data corresponding to the R-component reflected light intensity, reflected light intensity ratio data is obtained. Based on this reflected light intensity ratio data, the fundus image is reconstructed for glaucoma diagnosis.
    Type: Grant
    Filed: October 30, 2000
    Date of Patent: June 25, 2002
    Assignee: Kabushiki Kaisha Topcon
    Inventors: Kazuhiko Ohnuma, Yasufumi Fukuma, Hidetaka Aeba
  • Patent number: 5875017
    Abstract: An apparatus for simulating a retinal image obtained when a lens is used with a human eye. The apparatus can simulate intraocular lenses, contact lenses or eyeglass lenses. When intraocular lenses are simulated, a lens system 31 comprises photographic lenses and an intraocular lens mounting section. The intraocular lens is held within one or more liquid containing sections provided in the intraocular lens mounting section. The relative position of the photographic lenses and the intraocular lens is set by making the paraxial object point distance of a front refracting face of the intraocular lens substantially equal that calculated when the intraocular lens replaces a crystalline lens of Glustrand's ocular model. When simulating contact or eyeglass lenses, a front face of a lens disposed nearest the object in lens system 31 has substantially the same radius of curvature as that of a human cornea, and a contact lens supporting base has a shape corresponding to the conjunctiva of the eye.
    Type: Grant
    Filed: May 30, 1997
    Date of Patent: February 23, 1999
    Assignee: Hoya Corporation
    Inventors: Kazuhiko Ohnuma, Hua Qi, Atsuo Minato