Patents by Inventor Naoki Obi

Naoki Obi 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: 6730241
    Abstract: An object of the present invention is to provide a polymerizable liquid crystal composition incorporating a polymerizable liquid crystal compound which displays a low nematic phase temperature, displays excellent compatibility with other polymerizable liquid crystal compounds, and furthermore yields a product following polymerization, of good transparency and high mechanical strength.
    Type: Grant
    Filed: December 20, 2001
    Date of Patent: May 4, 2004
    Assignee: Dainippon Ink and Chemicals, Inc.
    Inventors: Naoki Obi, Seungtaeg Lee, Hiroshi Hasebe, Tatsuo Kawara
  • Publication number: 20030025104
    Abstract: An object of the present invention is to provide a polymerizable liquid crystal composition incorporating a polymerizable liquid crystal compound which displays a low nematic phase temperature, displays excellent compatibility with other polymerizable liquid crystal compounds, and furthermore yields a product following polymerization, of good transparency and high mechanical strength.
    Type: Application
    Filed: December 20, 2001
    Publication date: February 6, 2003
    Inventors: Naoki Obi, Seungtaeg Lee, Hiroshi Hasebe, Tatsuo Kawara
  • Patent number: 6169186
    Abstract: The invention relates to bismaleimides comprising mesogenic groups which consist, corresponding to (I), of two reactive terminal maleimide groups which are linked via linear or singly alkyl-substituted alkylene chains A, which are linked to an aromatic mesogen M via ester, amide or ether groups, wherein A, X, M and R are as defined in the specification. The invention, moreover, relates to oligomeric liquid crystalline bismaleimides of general formula (II) wherein A, X, M and R are as defined above, n represents and integer from 1 to 100 and B represents piperazinyl or a divalent radical which is derived from a primary or secondary para-substituted cyclic diamine, wherein B is bonded via the amino groups of the diamine. The invention also relates to methods of producing said bismaleimides.
    Type: Grant
    Filed: December 27, 1999
    Date of Patent: January 2, 2001
    Assignee: Dainippon Ink and Chemicals, Inc.
    Inventors: Masaru Imai, Rainer B. Frings, Gerwald F. Grahe, Joji Kawamura, Naoki Obi
  • Patent number: 5766833
    Abstract: An image-forming process developing a previously image-exposed silver halide photographic material with an alkaline developer containing a reductone compound as a main developing agent in the presence of a 1,2,5-thiadiazole compound and/or a 2,1,3-benzothiadiazole compound, and the silver halide photographic material and the photographic developer being used for the process are disclosed. In this case, the 1,2,5-thuiadiazole compound and/or the 2,1,3-benzothiadiazole may be contained in the silver halide photographic material and/or the alkaline developer. Super high-contrast images for photomechanical process having a gamma of higher than 15 and having no pepper and less fog can be obtained.
    Type: Grant
    Filed: July 8, 1997
    Date of Patent: June 16, 1998
    Assignee: Dainippon Ink and Chemicals Inc.
    Inventors: Kiyoshi Suematsu, Hiroaki Muratake, Haruhiko Kaji, Naoki Obi, Yasuhiko Kojima, Yasuo Shigemitsu
  • Patent number: 5683854
    Abstract: An image-forming process developing a previously image-exposed silver halide photographic material with an alkaline developer containing a reductone compound as a main developing agent in the presence of a 1,2,5-thiadiazole compound and/or a 2,1,3-benzothiadiazole compound, and the silver halide photographic material and the photographic developer being used for the process are disclosed. In this case, the 1,2,5-thuiadiazole compound and/or the 2,1,3-benzothiadiazole may be contained in the silver halide photographic material and/or the alkaline developer. Super high-contrast images for photomechanical process having a gamma of higher than 15 and having no pepper and less fog can be obtained.
    Type: Grant
    Filed: September 12, 1996
    Date of Patent: November 4, 1997
    Assignee: Dainippon Ink and Chemicals Inc.
    Inventors: Kiyoshi Suematsu, Hiroaki Muratake, Haruhiko Kaji, Naoki Obi, Yasuhiko Kojima, Yasuo Shigemitsu
  • Patent number: 5460919
    Abstract: A process of forming a super high-contrast negative image is disclosed, which comprises the steps of imagewise exposing a negative-working silver halide photographic material comprising a support having thereon one or more hydrophilic colloidal layers, at least one of the one or more hydrophilic colloidal layers being a negative-working silver halide emulsion layer, and then developing the photographic material with a developer containing an aminophenol derivative developing agent and a reductone compound in the existence of an organic compound having a negative reduction potential. A negative-working silver halide photographic material and a photographic developer being used for the image-forming process are also disclosed.
    Type: Grant
    Filed: July 22, 1994
    Date of Patent: October 24, 1995
    Assignee: Dainippon Ink and Chemicals, Inc.
    Inventors: Naoki Obi, Yasuhiko Kojima, Yasuo Shigemitsu, Jun Takeuchi, Kiyoshi Suematsu
  • Patent number: 5372911
    Abstract: A process of forming a super high-contrast negative image is disclosed, which comprises the steps of imagewise exposing a negative-working silver halide photographic material comprising a support having thereon one or more hydrophilic colloidal layers, at least one of the one or more hydrophilic colloidal layers being a negative-working silver halide emulsion layer, and then developing the photographic material with a developer containing an aminophenol derivative developing agent and a reductone compound in the existence of an organic compound having a negative reduction potential. A negative-working silver halide photographic material and a photographic developer being used for the image-forming process are also disclosed.
    Type: Grant
    Filed: June 11, 1992
    Date of Patent: December 13, 1994
    Assignee: Dainippon Ink and Chemicals, Inc.
    Inventors: Naoki Obi, Yasuhiko Kojima, Yasuo Shigemitsu, Jun Takeuchi, Kiyoshi Suematsu
  • Patent number: 5362621
    Abstract: A direct positive silver halide photographic material and a method for forming a high contrast image using the same are disclosed, in which a pre-fogged direct positive silver halide emulsion layer contains a salt of a nitrogen-containing compound having at least one pyridine nucleus and at least one pyridinium nucleus. The photographic material, after imagewise exposure, is developed with an alkaline developer containing a developing agent, preferably a reductance compound. The photographic material provides high contrast characteristics having a gamma exceeding 10.
    Type: Grant
    Filed: August 18, 1993
    Date of Patent: November 8, 1994
    Assignee: Dainippon Ink and Chemicals, Inc.
    Inventors: Naoki Obi, Kiyoshi Suematsu, Yasuhiko Kojima, Masatoshi Katayama, Yasuo Shigemitsu
  • Patent number: 5284733
    Abstract: A silver halide photographic material is disclosed. The photographic material comprises a support having coated thereon one or more hydrophilic colloidal layers, at least one of the hydrophilic colloidal layers being a negative working silver halide emulsion layer, wherein said silver halide emulsion layer or another hydrophilic colloidal layer contains a water-soluble polymer or copolymer having a quaternary ammonium salt in a repeating unit. The process for forming a high contrast negative image using the photographic material is also disclosed.
    Type: Grant
    Filed: October 1, 1991
    Date of Patent: February 8, 1994
    Assignee: Dainippon Ink and Chemicals, Inc.
    Inventors: Yasuhiko Kojima, Naoki Obi, Yasuo Shigemitsu, Kiyoshi Suematsu
  • Patent number: 5217842
    Abstract: A process of forming superhigh-contrast negative images is disclosed. The process comprises the steps of imagewise exposing a substantially surface latent image-type silver halide photographic material which is spectrally sensitized with a sensitizing dye and then developing said photographic material with a developer, wherein said photographic material contains a heterocyclic thione compound and said developer comprises (a) an aminophenol derivative developing agent, (b) a reductone compound, (c) a quaternary ammonium salt, and (d) a compound represented by formula (I): ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3, which may be the same or different, each represents a hydrogen atom, a nitro group, a halogen atom, or a cyano group, and wherein said development processing is carried out in the existence of at least one kind of a polyalkylene oxide or a derivative thereof. The process provides negative images of superhigh contrast having gamma over 10 substantially free from appearance of pepper.
    Type: Grant
    Filed: September 18, 1991
    Date of Patent: June 8, 1993
    Assignee: Dainippon Ink and Chemical, Inc.
    Inventors: Yasuhiko Kojima, Naoki Obi, Yasuo Shigemitsu
  • Patent number: 4724196
    Abstract: A lith-type silver halide photographic material comprising a tetrahydro-1,3,5-triazine-2-thione derivative and a polyalkylene oxide derivative.
    Type: Grant
    Filed: March 2, 1987
    Date of Patent: February 9, 1988
    Inventors: Tadao Shoji, Yonosuke Tsuka, Naoki Obi, Yasuhiko Kojima, Yasuo Shigemitsu