Patents by Inventor Madoka Tokumoto

Madoka Tokumoto 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: 7682590
    Abstract: In the present invention, a nonionic surfactant is noticed for a function of dispersing a carbon nanotube, and it is found that a mixture solution of an amide-based organic solvent and a polyvinylpyrrolidone (PVP) or of the amide-based organic solvent, the nonionic surfactant, and the polyvinylpyrrolidone (PVP) has an excellent function as a dispersant for the carbon nanotube. Ultrasonication is required for dispersing a carbon nanotube in the dispersant. The ultrasonication may be carried out in the step of dispersing the carbon nanotube in the nonionic surfactant and/or the amide-based polar organic solvent, and then the polyvinylpyrrolidone (PVP) may be mixed with the resultant dispersion. Alternatively, a mixture solution of the nonionic surfactant and/or the amide-based polar organic solvent, and the polyvinylpyrrolidone (PVP) is prepared, and then the ultrasonication may be carried out in the step of dispersing the carbon nanotube therein.
    Type: Grant
    Filed: November 16, 2004
    Date of Patent: March 23, 2010
    Assignee: National Institute of Advanced Industrial Science and Technology
    Inventors: Youichi Sakakibara, Madoka Tokumoto, Oleksiy Rozhin, Hiromichi Kataura
  • Publication number: 20080266643
    Abstract: An electrode member (10A) for a reversibly color changeable display device, having: a transparent electrically-conductive structural layer (10C); and a reversibly color changeable film layer (3) disposed at one side of the transparent electrically-conductive structural layer (10C), the reversibly color changeable film layer (3) being formed by a dispersion liquid containing ultrafine particles, so that a color of the reversibly color changeable film layer (3) can be changed under control, by applying a voltage to the transparent electrically-conductive structural layer (10C) and an electrically-conductive counter electrode structural layer (10B), with an electrolyte layer (4) provided at one side of the reversibly color changeable film layer (3), and the electrically-conductive counter electrode structural layer (10B) provided at an outside of the electrolyte layer (4).
    Type: Application
    Filed: August 16, 2006
    Publication date: October 30, 2008
    Applicants: National Institute of Advanced Industrial Science and Technology, Japan Advanced Institute of Science and Technology
    Inventors: Tohru Kawamoto, Hisashi Tanaka, Shigeo Hara, Madoka Tokumoto, Masato Kurihara, Masatomi Sakamoto, Mami Yamada
  • Publication number: 20080258117
    Abstract: A carbon nanotube-dispersed polyimide saturable absorber excellent in an optical quality, obtainable by mixing a carbon nanotube dispersion liquid comprising a carbon nanotube, an amide-based polar organic solvent, and a nonionic surfactant and/or a polyvinylpyrrolidone (PVP) with a mixture solution of a solvent soluble polyimide and an organic solvent. A method for producing the same, comprising the steps of dispersing a single-walled carbon nanotube in a mixture solution of an amide-based polar organic solvent and a nonionic surfactant under intensive stirring, mixing the resultant dispersion liquid with a polyimide mixed organic solvent, and removing the solvent.
    Type: Application
    Filed: March 3, 2005
    Publication date: October 23, 2008
    Inventors: Youichi Sakakibara, Madoka Tokumoto, Hiromichi Kataura
  • Publication number: 20070224106
    Abstract: In the present invention, a nonionic surfactant is noticed for a function of dispersing a carbon nanotube, and it is found that a mixture solution of an amide-based organic solvent and a polyvinylpyrrolidone (PVP) or of the amide-based organic solvent, the nonionic surfactant, and the polyvinylpyrrolidone (PVP) has an excellent function as a dispersant for the carbon nanotube. Ultrasonication is required for dispersing a carbon nanotube in the dispersant. The ultrasonication maybe carried out in the step of dispersing the carbon nanotube in the nonionic surfactant and/or the amide-based polar organic solvent, and then the polyvinylpyrrolidone (PVP) may be mixed with the resultant dispersion. Alternatively, a mixture solution of the nonionic surfactant and/or the amide-based polar organic solvent, and the polyvinylpyrrolidone (PVP) is prepared, and then the ultrasonication may be carried out in the step of dispersing the carbon nanotube therein.
    Type: Application
    Filed: November 16, 2004
    Publication date: September 27, 2007
    Inventors: Youichi Sakakibara, Madoka Tokumoto, Oleksiy Rozhin, Hiromichi Kataura
  • Publication number: 20050254760
    Abstract: Non-linear optical characteristics of a carbon nanotube are applied to an optical communication field. An optical transmission medium (12) obtained by incorporating a carbon nanotube having optically non-linear characteristics into a non-linear light transmitting medium is assembled between typical optical transmission medium (14a, 14b) and is used by being combined with an optical circulator (16), whereby the resultant product is used as an optical fuse (breaker) that transmits a normal signal light A but blocks the transmission of an abnormal-intensity light inadvertently produced.
    Type: Application
    Filed: May 14, 2003
    Publication date: November 17, 2005
    Inventors: Youichi Sakakibara, Madoka Tokumoto, Yohji Achiba, Hiromichi Kataura, Yuichi Tanaka, Mark Jablonski
  • Patent number: 6936322
    Abstract: An optical element according to the present invention has a thin film, in which single-wall carbon nanotubes are laminated, and utilizes a saturable absorption function of the single-wall carbon nanotubes. Further, in a method for producing the optical element according to the present invention, the thin film is formed by spraying, to a body to be coated, a dispersion liquid prepared by dispersing the single-wall carbon nanotubes in a dispersion medium. Accordingly, a nonlinear optical element, which can operate in an optical communication wavelength region and which is extremely inexpensive and efficient, and a method for producing the optical element can be provided.
    Type: Grant
    Filed: October 17, 2002
    Date of Patent: August 30, 2005
    Assignee: National Institute of Advanced Industrial Science and Technology
    Inventors: Youichi Sakakibara, Madoka Tokumoto, Satoshi Tatsuura, Yohji Achiba, Hiromichi Kataura
  • Publication number: 20050129382
    Abstract: An increase in the span of the transmission distance is aimed at by reducing unwanted ASE generated during optical communication. A carbon nanotube is employed as a saturable absorber 15 and this saturable absorber constitutes a noise reduction apparatus that has the function of cutting off or reducing transmission of unwanted ASE or the like which is of weak signal light intensity and of allowing transmission of signal light of strong light intensity. This noise reduction apparatus is arranged for example in the transmission path of signal light of a bidirectional excitation type EDFA, more precisely the apparatus is inserted in the latter stage of the EDF 40. In this way, carbon nanotubes having a saturable absorption function can be utilized in the field of optical communication.
    Type: Application
    Filed: February 19, 2003
    Publication date: June 16, 2005
    Inventors: Youichi Sakakibara, Madoka Tokumoto, Yohji Achiba, Hiromichi Kataura, Mark Jablonski, Yuichi Tanaka
  • Publication number: 20050069669
    Abstract: An optical element according to the present invention has a thin film, in which single-wall carbon nanotubes are laminated, and utilizes a saturable absorption function of the single-wall carbon nanotubes. Further, in a method for producing the optical element according to the present invention, the thin film is formed by spraying, to a body to be coated, a dispersion liquid prepared by dispersing the single-wall carbon nanotubes in a dispersion medium. Accordingly, a nonlinear optical element, which can operate in an optical communication wavelength region and which is extremely inexpensive and efficient, and a method for producing the optical element can be provided.
    Type: Application
    Filed: October 17, 2002
    Publication date: March 31, 2005
    Inventors: Youichi Sakaibara, Madoka Tokumoto, Satoshi Tatsura, Yohji Achiba, Hiromichi kataura