Patents by Inventor Yoshiro Oikawa

Yoshiro Oikawa 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: 6464360
    Abstract: The projection type display apparatus according to the present invention has a prism for separating incident light into a plurality of light components and combining the plurality of modulated color components. The prism is constituted by a plurality of prism assemblies, each including an optical member made of an optically transparent material having a photoelastic constant whose absolute value is not greater than +1.5×10−8 cm2/N with respect to the incident light. More preferably, these plurality of prism assemblies are arranged such that each of a plurality of the separated color components is totally reflected by any of the prism assemblies.
    Type: Grant
    Filed: December 14, 2000
    Date of Patent: October 15, 2002
    Assignee: Nikon Corporation
    Inventors: Tetsuo Hattori, Masatoshi Sato, Mikio Okamoto, Yoshiro Oikawa
  • Publication number: 20010000678
    Abstract: The projection type display apparatus according to the present invention has a prism for separating incident light into a plurality of light components and combining the plurality of modulated color components. The prism is constituted by a plurality of prism assemblies, each including an optical member made of an optically transparent material having a photoelastic constant whose absolute value is not greater than +1.5×10−8 cm2/N with respect to the incident light. More preferably, these plurality of prism assemblies are arranged such that each of a plurality of the separated color components is totally reflected by any of the prism assemblies.
    Type: Application
    Filed: December 14, 2000
    Publication date: May 3, 2001
    Inventors: Tetsuo Hattori, Masatoshi Sato, Mikio Okamoto, Yoshiro Oikawa
  • Patent number: 6062694
    Abstract: The present invention relates to a projection type display apparatus which utilizes a polarizing beam splitter and/or a color separating/combining optical system, each being constituted by an optically transparent material block having a specific characteristic, thereby being capable of securing optically stable performances against influences of various thermal and external stresses and suppressing image quality deterioration to a low level. In particular, in this projection type display apparatus, the polarizing beam splitter used for a polarized light separating optical system and analyzing optical system, and/or an optical member servicing as a color separating/combining optical system are constituted by an optically transparent material block in which a wavelength where the absolute value of a photoelastic constant becomes a minimum level exists in a wavelength range of a blue light component.
    Type: Grant
    Filed: December 18, 1997
    Date of Patent: May 16, 2000
    Assignee: Nikon Corporation
    Inventors: Yoshiro Oikawa, Motoi Ueda, Kazufumi Ishibashi, Masaaki Kusano, Tetsuo Hattori
  • Patent number: 5808795
    Abstract: A projection type display apparatus includes a spatial light modulator, a polarizing beam splitter formed of members of a transparent material, and a projection optical system. The polarizing beam splitter includes a dielectric multilayer film, and a first transparent material member and a second transparent material member sandwiching the dielectric multilayer film. Each of the first and second transparent material members is made of a transparent material with a refractive index of at least 1.8 and with an absolute value of the photoelastic constant being no more than 1.5.times.10.sup.-8 cm.sup.2 /N for light of wavelengths 0.4 .mu.m to 0.7 .mu.m, incident to the polarizing beam splitter.
    Type: Grant
    Filed: March 6, 1996
    Date of Patent: September 15, 1998
    Assignee: Nikon Corporation
    Inventors: Hideaki Shimomura, Kiyoshi Numazaki, Yoshiro Oikawa, Naotaka Shimamura, Motoi Ueda, Takeshi Hasegawa
  • Patent number: 5798819
    Abstract: Methods and apparatus are disclose for obtaining a bright projected color image. In a representative apparatus, polarized beam splitters (one for each primary color of an image to be projected) separate p-polarized light and s-polarized light for each of the primary colors. Each separated s- and p-polarized light for each color enters a respective spatial light modulator. For each primary color, modulated light fluxes produced by the two spatial light modulators, which perform modulation of the same image, are analyzed and integrated by the polarized beam splitters. The analyzed and integrated light fluxes for each primary color are color integrated, either by projection using separate projection lenses for each color, or by a cross-dichroic prism followed by projection using a single lens.
    Type: Grant
    Filed: December 11, 1996
    Date of Patent: August 25, 1998
    Assignee: Nikon Corporation
    Inventors: Tetsuo Hattori, Yoshiro Oikawa
  • Patent number: 5690407
    Abstract: A shutter has a cylindrical take-up member rotatable about the central shaft thereof, and a thin board having one end portion thereof fixed to the outer peripheral surface of the take-up member and deformable into a state rolled on the outer peripheral surface of the take-up member and having a spring force for returning to a flat state. The thin board is capable of operating between a liberating position in which in conformity with the rotated position of the take-up member, it is rolled onto the take-up member and retracts from a predetermined optical path to thereby permit the passage of light in the optical path and an intercepting position in which it is unrolled from the take-up member and assumes a flat shape and protrudes into the predetermined optical path to thereby intercept the light.
    Type: Grant
    Filed: May 29, 1996
    Date of Patent: November 25, 1997
    Assignee: Nikon Corporation
    Inventors: Nobuyuki Kikuchi, Yoshiro Oikawa, Tetsuo Hattori
  • Patent number: 5666578
    Abstract: A camera according to the present invention is so arranged that a half mirror is disposed in an optical path between a taking lens and a photographic film strip to be exposed so as to reflect a part of subject image incident thereinto. The thus reflected subject image is received by CCD, which converts it into electric image data. The image data is converted into binary codes, and the codes are written by a magnetic head in a magnetic layer provided on the back face of the photographic film strip. On the other hand, the image data received by the CCD is displayed for a photographer in a finder through a liquid crystal display at all times.
    Type: Grant
    Filed: August 2, 1996
    Date of Patent: September 9, 1997
    Assignee: Nikon Corporation
    Inventors: Yoshiro Oikawa, Masaaki Kusano, Hideaki Shimomura, Naotaka Shimamura, Kiyoshi Numazaki