Patents by Inventor Hirotaka Sakuma

Hirotaka Sakuma 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: 11181684
    Abstract: An optical fiber is formed from silica glass, and includes a core, a first cladding which surrounds the core and has a refractive index lower than the refractive index of the core, and a second cladding which surrounds the first cladding and has a refractive index that is lower than the refractive index of the core and higher than the refractive index of the first cladding. The second cladding is divided into an inner region that is in contact with the first cladding and an outer region which surrounds the inner region and has a thickness that is half the thickness of the second cladding or less, while being 5 ?m or more. The residual stress in at least a part of the outer region is a compressive stress.
    Type: Grant
    Filed: August 27, 2020
    Date of Patent: November 23, 2021
    Assignee: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Yoshiaki Tamura, Hirotaka Sakuma, Keisei Morita
  • Patent number: 11169322
    Abstract: An optical fiber having an effective area that can be easily increased and bending loss characteristics that can be easily improved is provided. The optical fiber includes a glass fiber including a core and a cladding; a first resin coating layer that is in contact with the glass fiber and surrounds the glass fiber; and a second resin coating layer that surrounds the first resin coating layer and has a Young's modulus greater than a Young's modulus of the first resin coating layer. An effective area is greater than or equal to 110 ?m2 and less than or equal to 180 ?m2 at a wavelength of 1550 nm. A cable cut-off wavelength is less than or equal to 1530 nm. A uniformity of thickness of the first resin coating layer is greater than or equal to 60% and less than or equal to 80%.
    Type: Grant
    Filed: February 27, 2019
    Date of Patent: November 9, 2021
    Assignee: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Yuki Kawaguchi, Yoshiaki Tamura, Hirotaka Sakuma
  • Publication number: 20210294028
    Abstract: One embodiment of the present disclosure relates to an optical fiber having lower transmission loss. The optical fiber is an optical fiber comprised of silica-based glass and includes a core including a central axis and a cladding. The cladding surrounds the core and has a refractive index lower than a refractive index of the core. The core contains phosphorus, chlorine, and fluorine. The core further includes an alkali metal element or an alkaline earth metal element. In a cross section of the optical fiber orthogonal to the central axis, a ratio Rp/Ra of a radius Rp of a phosphorus-containing region with respect to a radius Ra of the core is 0.3 or more.
    Type: Application
    Filed: June 4, 2021
    Publication date: September 23, 2021
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Hirotaka SAKUMA, Yoshiaki TAMURA, Yuki KAWAGUCHI, Masato SUZUKI
  • Patent number: 11118005
    Abstract: Embodiments of the present invention relate to a composition containing a polymer or oligomer (A) and an initiator (B), wherein the polymer or oligomer (A) contains no alkyl groups of 5 or more carbon atoms, contains at least one type of structural unit selected from the group consisting of a structural unit containing an aromatic amine structure and a structural unit containing a carbazole structure, and contains, at one or more terminals, a structural unit containing a thienyl group which may have a substituent, and a degree of solubility of the composition is capable of being changed by applying heat, light, or both heat and light.
    Type: Grant
    Filed: October 3, 2016
    Date of Patent: September 14, 2021
    Assignee: Showa Denko Materials Co., Ltd.
    Inventors: Kazuyuki Kamo, Hirotaka Sakuma, Kenichi Ishitsuka, Tomotsugu Sugioka, Yuki Yoshinari, Ryo Honna, Daisuke Ryuzaki
  • Patent number: 11048040
    Abstract: The optical fiber offered is capable of not only restraining the attenuation due to glass defects, but also reducing the increase of manufacturing cost. The optical fiber is made of silica glass and includes a core and a cladding. The cladding encloses the core and has a refractive index smaller than that of the core. When the core is divided into inner core and outer core at half of the radius of the core, the average chlorine concentration of the inner core is larger than that of the outer core. The core includes any of the alkali metal group.
    Type: Grant
    Filed: April 15, 2020
    Date of Patent: June 29, 2021
    Assignee: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Hirotaka Sakuma, Yoshiaki Tamura, Keisei Morita, Yuki Kawaguchi
  • Publication number: 20210179771
    Abstract: One embodiment relates to a charge transport polymer containing a molecular chain and terminal groups bonded to the molecular chain, wherein the terminal groups include a terminal group P containing a polymerizable functional group and a terminal group EW containing an aromatic hydrocarbon group substituted with an electron-withdrawing substituent, the terminal group P includes a terminal group represented by formula (P1) shown below, and among the carbon atoms contained in the ring of the aromatic hydrocarbon group, if the carbon atom that is bonded to the molecular chain is numbered 1, and numbers are assigned in order to the adjoining carbon atoms, then the electron-withdrawing substituent is bonded to a carbon atom numbered 1+2n (wherein n is an integer of 1 or greater).
    Type: Application
    Filed: October 27, 2017
    Publication date: June 17, 2021
    Inventors: Iori FUKUSHIMA, Hirotaka SAKUMA, Kenichi ISHITSUKA, Kazuyuki KAMO, Shunsuke KODAMA, Tomotsugu SUGIOKA, Tomomi UCHIYAMA, Ryota MORIYAMA, Ryo HONNA
  • Publication number: 20210179770
    Abstract: One embodiment relates to a charge transport polymer containing a molecular chain and terminal groups bonded to the molecular chain, wherein the terminal groups include a terminal group P containing a polymerizable functional group and a terminal group B containing an aromatic hydrocarbon group substituted with a branched or cyclic substituent, and among the carbon atoms contained in the ring of the aromatic hydrocarbon group, if the carbon atom that is bonded to the molecular chain is numbered 1, and numbers are assigned in order to the adjoining carbon atoms, then the branched or cyclic substituent is bonded to a carbon atom numbered 1+2n (wherein n is an integer of 1 or greater).
    Type: Application
    Filed: October 27, 2017
    Publication date: June 17, 2021
    Inventors: Iori FUKUSHIMA, Hirotaka SAKUMA, Kenichi ISHITSUKA, Kazuyuki KAMO, Shunsuke KODAMA, Tomotsugu SUGIOKA, Tomomi UCHIYAMA, Ryota MORIYAMA, Ryo HONNA
  • Publication number: 20210171390
    Abstract: An optical fiber includes a core, and a cladding. When a refractive index of silica glass is set as no, a refractive index of the core is set as n1, and a refractive index of the cladding is set as n2, a relative refractive index difference ? defined by Expression (1): ?[%]=100×(n12?n22)/2n02??(1) is 0.2% or higher. A ratio of a maximum value of a concentration of the dopant composed of the alkali metal element or the alkaline-earth metal element in the cladding to a maximum value of a concentration of the dopant composed of the alkali metal element or the alkaline-earth metal element in the core is 0.06 or higher and 0.25 or lower.
    Type: Application
    Filed: January 25, 2021
    Publication date: June 10, 2021
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Yoshiaki TAMURA, Hirotaka SAKUMA, Akiko FUNAKOSHI
  • Patent number: 10989864
    Abstract: The optical fiber has an effective area that is greater than or equal to 110 ?m2 and less than or equal to 180 ?m2 at a wavelength of 1550 nm and a cable cut-off wavelength of less than or equal to 1530 nm. An average value of a glass outer diameter in a longitudinal direction is 125±0.5 ?m. When ? is a standard deviation of the glass outer diameter in the longitudinal direction, 3? is greater than or equal to 0.1 ?m and less than or equal to 0.5 ?m.
    Type: Grant
    Filed: July 2, 2020
    Date of Patent: April 27, 2021
    Assignee: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Yuki Kawaguchi, Yoshiaki Tamura, Hirotaka Sakuma
  • Publication number: 20200400879
    Abstract: An optical fiber according to an embodiment of the present disclosure includes a core and a cladding which surrounds the core. The cladding includes an inner cladding layer which surrounds the core and an outer cladding layer which surrounds the inner cladding layer. A maximum value ?n1max of a relative refractive index difference of the core, a minimum value ?n2min of a relative refractive index difference of the inner cladding layer, and a maximum value ?n3max of a relative refractive index difference of the outer cladding layer satisfy a relationship of ?n2min<?n3max<?n1max. A residual stress ?(r) at a radial position r satisfies |d?(r)/dr|?30 MPa/?m in the cladding.
    Type: Application
    Filed: June 11, 2020
    Publication date: December 24, 2020
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Yuki KAWAGUCHI, Yoshiaki TAMURA, Hirotaka SAKUMA, Masato SUZUKI
  • Publication number: 20200393613
    Abstract: An optical fiber is formed from silica glass, and includes a core, a first cladding which surrounds the core and has a refractive index lower than the refractive index of the core, and a second cladding which surrounds the first cladding and has a refractive index that is lower than the refractive index of the core and higher than the refractive index of the first cladding. The second cladding is divided into an inner region that is in contact with the first cladding and an outer region which surrounds the inner region and has a thickness that is half the thickness of the second cladding or less, while being 5 ?m or more. The residual stress in at least a part of the outer region is a compressive stress.
    Type: Application
    Filed: August 27, 2020
    Publication date: December 17, 2020
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Yoshiaki TAMURA, Hirotaka SAKUMA, Keisei MORITA
  • Publication number: 20200333528
    Abstract: The optical fiber has an effective area that is greater than or equal to 110 ?m2 and less than or equal to 180 ?m2 at a wavelength of 1550 nm and a cable cut-off wavelength of less than or equal to 1530 nm. An average value of a glass outer diameter in a longitudinal direction is 125±0.5 ?m. When ? is a standard deviation of the glass outer diameter in the longitudinal direction, 3? is greater than or equal to 0.1 ?m and less than or equal to 0.5 ?m.
    Type: Application
    Filed: July 2, 2020
    Publication date: October 22, 2020
    Inventors: Yuki KAWAGUCHI, Yoshiaki TAMURA, Hirotaka SAKUMA
  • Publication number: 20200292750
    Abstract: An optical fiber according to an embodiment has a structure for enabling determination of improvement in transmission loss at a preform stage. The optical fiber includes: a core containing Cl and having an average refractive index lower than a refractive index of pure silica glass; a first cladding containing F; a second cladding; and a resin coating, in which an effective area at a wavelength of 1550 nm is 135 ?m2 or more and 170 ?m2 or less, a ratio of the effective area to a cutoff wavelength ?C is 85.0 ?m or more, a bending loss of an LP01 mode at a wavelength of 1550 nm and at a bending radius of R15 mm is less than 4.9 dB per 10 turns, and the resin coating includes a primary resin layer having a Young's modulus of 0.3 MPa or less.
    Type: Application
    Filed: March 11, 2020
    Publication date: September 17, 2020
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Masato SUZUKI, Yuki KAWAGUCHI, Hirotaka SAKUMA, Yoshiaki TAMURA, Takemi HASEGAWA
  • Publication number: 20200249393
    Abstract: The optical fiber offered is capable of not only restraining the attenuation due to glass defects, but also reducing the increase of manufacturing cost. The optical fiber is made of silica glass and includes a core and a cladding. The cladding encloses the core and has a refractive index smaller than that of the core. When the core is divided into inner core and outer core at half of the radius of the core, the average chlorine concentration of the inner core is larger than that of the outer core. The core includes any of the alkali metal group.
    Type: Application
    Filed: April 15, 2020
    Publication date: August 6, 2020
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Hirotaka SAKUMA, Yoshiaki TAMURA, Keisei MORITA, Yuki KAWAGUCHI
  • Publication number: 20200241198
    Abstract: An optical fiber in which the increase of attenuation can be reduced is offered. An optical fiber is made of silica glass and includes a core and a cladding enclosing the core. The refractive index of the cladding is smaller than that of the core. The core includes chlorine and any of the alkali metal group, The chlorine concentration is 1 ppm or more in the whole region of the core. In the whole region of the core, the absolute value of rate of radial change of the chlorine concentration is smaller than 2000 ppm/?m.
    Type: Application
    Filed: April 13, 2020
    Publication date: July 30, 2020
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Hirotaka SAKUMA, Yoshiaki TAMURA, Yuki KAWAGUCHI
  • Patent number: 10723650
    Abstract: An optical fiber preform includes a silica-glass core portion, and a cladding portion surrounding the core portion, the cladding portion being composed of a fluorine-containing silica glass having a lower refractive index than the core portion, the core portion including a first region that does not include the central axis thereof, the first region containing a first dopant selected from sodium, potassium, and compounds thereof, and a second region that includes the central axis, the second region containing a second dopant that reduces the viscosity of the silica glass, the second dopant having a diffusion coefficient of 1×10?12 cm2/s or more and less than the first dopant at 2,000° C. to 2,300° C., in which the entire core portion has an average first dopant concentration of 10 atomic ppm or more and 2,000 atomic ppm or less and an average second dopant concentration of 10 atomic ppm or more.
    Type: Grant
    Filed: July 10, 2018
    Date of Patent: July 28, 2020
    Assignee: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Keisei Morita, Yoshiaki Tamura, Hirotaka Sakuma
  • Publication number: 20200235312
    Abstract: A charge transport material which can be used for an organic electronic element and contains a charge transport polymer capable of improving the element characteristics is provided, and an ink composition containing the material is also provided. Further, an organic electronic element and an organic EL element having excellent element characteristics, and a display element, an illumination device and a display device that use these elements are also provided. More specifically, an organic electronic material containing a charge transport polymer or oligomer having at least one structural unit containing a substituted or unsubstituted dibenzofuran structure or dibenzothiophene structure is provided.
    Type: Application
    Filed: February 2, 2018
    Publication date: July 23, 2020
    Inventors: Tomotsugu SUGIOKA, Kenichi ISHITSUKA, Yuki YOSHINARI, Ryo HONNA, Hirotaka SAKUMA
  • Publication number: 20200161556
    Abstract: One embodiment relates to an organic electronic material containing a charge transport polymer, wherein the charge transport polymer is a polymer which, when 25 ?L portions of methanol are added dropwise and stirred into 1,000 ?L of a solution containing the charge transport polymer and toluene in a ratio of 20 mg of the charge transport polymer per 2,290 ?L of toluene, the amount of methanol added by the time cloudiness develops in the solution is greater than 350 ?L.
    Type: Application
    Filed: July 4, 2018
    Publication date: May 21, 2020
    Inventors: Kazuyuki KAMO, Iori FUKUSHIMA, Ryota MORIYAMA, Shunsuke KODAMA, Naoki ASANO, Hirotaka SAKUMA
  • Patent number: 10656326
    Abstract: An optical fiber in which the increase of attenuation can be reduced is offered. An optical fiber is made of silica glass and includes a core and a cladding enclosing the core. The refractive index of the cladding is smaller than that of the core. The core includes chlorine and any of the alkali metal group. The chlorine concentration is 1 ppm or more in the whole region of the core. In the whole region of the core, the absolute value of rate of radial change of the chlorine concentration is smaller than 2000 ppm/?m.
    Type: Grant
    Filed: July 16, 2019
    Date of Patent: May 19, 2020
    Assignee: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Hirotaka Sakuma, Yoshiaki Tamura, Yuki Kawaguchi
  • Patent number: 10656329
    Abstract: The optical fiber offered is capable of not only restraining the attenuation due to glass defects, but also reducing the increase of manufacturing cost. The optical fiber is made of silica glass and includes a core and a cladding. The cladding encloses the core and has a refractive index smaller than that of the core. When the core is divided into inner core and outer core at half of the radius of the core, the average chlorine concentration of the inner core is larger than that of the outer core. The core includes any of the alkali metal group.
    Type: Grant
    Filed: April 17, 2019
    Date of Patent: May 19, 2020
    Assignee: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Hirotaka Sakuma, Yoshiaki Tamura, Keisei Morita, Yuki Kawaguchi