Patents by Inventor Hiroshi Yokota

Hiroshi Yokota 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: 4832720
    Abstract: A multi-core optical fiber with improved dimensional accuracy is produced by a method comprisinginserting at least two core glass rods in bores formed in a cladding glass rod having a refractive index lower than that of the core glass rods to be inserted,heating a composite of the cladding glass rod and the core glass rods to integrate them together, anddrawing the integrated composite to fabricate a multi-core optical fiber.The drawing may be carried out simultaneously with the integration step.
    Type: Grant
    Filed: September 28, 1987
    Date of Patent: May 23, 1989
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Minoru Watanabe, Hiroshi Yokota, Shuzo Suzuki, Hiroshi Suganuma
  • Patent number: 4829309
    Abstract: A plane antenna comprises a power-supply circuit, a radiator circuit and an earthing conductor which are stacked respectively with a dielectric layer interposed between them, in which the power-supply and radiator circuits are made independent of each other as electromagnetically coupled to each other and at least one of the dielectric layers is formed with a foamed resin, whereby insertion loss can be reduced to remarkably improve the antenna characteristics. Only with the interposition of the foamed resin dielectric layer or layers, an effective separation is achieved between at least the power-supply circuit and the earthing conductor or the power-supply circuit and the radiator circuit, for a large extent improvement in the assembling ability.
    Type: Grant
    Filed: August 4, 1987
    Date of Patent: May 9, 1989
    Assignee: Matsushita Electric Works, Ltd.
    Inventors: Katsuya Tsukamoto, Yasuhiro Fujii, Yasumasa Ogawa, Sadaaki Kondo, Kyoji Masamoto, Masakatsu Niwa, Masayuki Matsuo, Yoshihiro Kitsuda, Hajime Takeda, Shoji Miyanari, Hiroshi Yokota, Shuji Taniguchi
  • Patent number: 4822399
    Abstract: A glass preform for use in the fabrication of a dispersion shifted single mode optical fiber is produced by a method for comprising steps of inserting a core member consisting of an inner core part made of a germanium-added quartz glass which optionally contains fluorine and an outer core part made of a quartz glass having a refractive index smaller than that of the inner core part in a glass tube made of a fluorine-added quartz glass having a refractive index smaller than that of the outer core part, heating the core member and the glass tube to collapse the glass tube and fuse them together to produce a glass perform. The glass preform comprises a core member consisting of an inner core part made of GeO.sub.2 -SiO.sub.2 glass or GeO.sub.2 -F-SiO.sub.2 glass and an outer core part made of F-SiO.sub.2 glass and a cladding made of F-SiO.sub.2 glass and provides a dispersion shifted single mode optical fiber having reduced attenuation of light transmission in the 1.5 .mu.m wavelength band.
    Type: Grant
    Filed: June 10, 1987
    Date of Patent: April 18, 1989
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Hiroo Kanamori, Hiroshi Yokota, Gotaro Tanaka, Yoichi Ishiguro, Masahiro Takagi, Hiroshi Suganuma, Masayuki Shigematsu
  • Patent number: 4801943
    Abstract: A plane antenna assembly comprises a plurality of antenna bases and a signal composing means including amplifiers each connected to output part of each antenna base for composing respective outputs of the antenna bases amplified through the amplifiers, whereby a composite antenna output is obtained in correspondence to the number of the antenna bases and in an excellent S/N ratio.
    Type: Grant
    Filed: January 16, 1987
    Date of Patent: January 31, 1989
    Assignee: Matsushita Electric Works, Ltd.
    Inventors: Yasuo Yabu, Kazuhisa Akiyama, Toshio Abiko, Minoru Kanda, Mikio Komatsu, Hirohumi Ishizaki, Hidetsugu Nunoya, Yasumasa Ogawa, Hiroshi Yokota
  • Patent number: 4797143
    Abstract: An improved process for the production of optical fiber porous preforms of predetermined refractive index distribution by the vapor-phase deposition method is disclosed wherein a glass material and a dopant material are subjected to flame oxidation by the use of an oxyhydrogen burner to form fine glass particles which are deposited on one end of a supporting rod adapted to move apart from the oxyhydrogen burner while rotating to allow a rod-like porous preform to grow thereon. The improved process is characterized in that the correlation between the shape of the deposition face and the refractive index distribution is previously determined mathematically, and on a basis of the correlation therebetween, a process variable such as the distance between the porous preform and the burner is adjusted to produce the desired shape of the deposition face whereby there can be obtained an optimum refractive index distribution.
    Type: Grant
    Filed: July 19, 1985
    Date of Patent: January 10, 1989
    Assignees: Nippon Telegraph & Telephone Public Corporation, Sumitomo Electric Industries, Ltd.
    Inventors: Kazunori Chida, Hiroshi Yokota, Michihisa Kyoto, Hisao Sato, Minoru Watanabe, Naoki Yoshioka
  • Patent number: 4793842
    Abstract: A rod-in-tube method for producing a glass preform for use in the fabrication of an optical fiber, which comprises steps of inserting a glass rod constituting a core material in a glass tube constituting a cladding material, heating the rod-tube composite by an outer heating source with introducing, in the gap between the rod and the tube, a gaseous mixture containing a silicon halogenide, a fluorine-containing compound and oxygen gas in which a ratio of silicon and fluorine (Si/F) is larger than 1/300 and smaller than 1/5, and heating and fusing the composite at a temperature not lower than 1,900.degree. C. with filling the gap by a gaseous mixture comprising a halogen-containing compound and oxygen gas; from which glass preform, an optical fiber with low attenuation of light transmission, particularly in a long wavelength range, is fabricated.
    Type: Grant
    Filed: December 21, 1987
    Date of Patent: December 27, 1988
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Hiroshi Yokota, Hiroo Kanamori, Gotaro Tanaka, Hiroshi Suganuma, Toshio Danzuka
  • Patent number: 4781740
    Abstract: A method for producing a glass preform for an optical fiber comprising jetting SiCl.sub.4 as a glass-forming raw material and an insert gas from a first nozzle of a multi-nozzle burner and, as another glass-forming raw material, at least one hydrogen-containing silicon compound with larger oxidation or hydrolysis reaction heat than that of SiCl.sub.4 selected from the group consisting of SiHCl.sub.3, SiH.sub.2 Cl.sub.2, SiH.sub.3 Cl and SiH.sub.4 from a second nozzle surrounding the first nozzle, flame hydrolyzing or oxidizing the glass-forming raw materials to synthesize glass soot particles, depositing the glass soot particles on a starting member to form a porous soot preform with a controlled bulk density distribution and heating and sintering the soot preform to obtain a transparent glass preform, by which a large glass preform is stably produced without cracking.
    Type: Grant
    Filed: February 19, 1987
    Date of Patent: November 1, 1988
    Assignee: Sumimoto Electric Industries, Ltd.
    Inventors: Toshio Danzuka, Hiroshi Yokota, Yoichi Ishiguro
  • Patent number: 4765815
    Abstract: A method for producing a glass preform for an optical fiber by means at least two burners, comprising jetting a glass raw material containing SiCl.sub.4 from the first center burner and a hydrogen-containing silicon compound with larger reaction heat than SiCl.sub.4 from at least one second burner, flame hydrolyzing the glas raw material to synthesizing fine glass particles, depositing the fine glass particles on a starting member to form a porous soot preform and heating and sintering the soot preform to obtain a transparent glass preform, by which a large preform is stably produced and a bulk density of the preform is easily controlled.
    Type: Grant
    Filed: August 20, 1987
    Date of Patent: August 23, 1988
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Toshio Danzuka, Hiroshi Yokota, Yoichi Ishiguro
  • Patent number: 4737179
    Abstract: A method for producing a glass preform for use in fabrication of an optical fiber, which comprises steps of forming a cylindrical rod of glass having a refractive index distribution with axial symmetry around the rod axis by an VAD method, stretching the rod glass to decrease its diameter, inserting the stretched rod in a glass tube having a refractive index distribution with axial symmetry around the tube axis and heating and melting a complex of the stretched rod and the tube to integrate them from the glass preform produced by the method, an optical fiber having precisely controlled refractive index distribution can be fabricated.
    Type: Grant
    Filed: August 4, 1986
    Date of Patent: April 12, 1988
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Gotaro Tanaka, Hiroshi Yokota, Shigeru Tanaka, Hiroo Kanamori, Hiroshi Suganuma
  • Patent number: 4720666
    Abstract: An electric braking apparatus for exerting the electric braking action (dynamic braking action) on a generator, further concretely a generator with a brushless exciter which is so constructed that a rectifying circuit for applying field voltage to the brushless exciter as a braking current to be applied to the generator is normally applied with exciting voltage at least during the running of the generator, thereby enabling the electric braking to be applied even on the generator which uses the brushless exciter and which has hitherto never been applicable of the same.
    Type: Grant
    Filed: June 3, 1986
    Date of Patent: January 19, 1988
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventor: Hiroshi Yokota
  • Patent number: 4679100
    Abstract: A rotary head type magnetic recording and reproducing device intended for dubbing one tape from another wherein the effects of vibration, jitter, etc., during the dubbing operation are substantially eliminated. First and second rotary heads, one for each of the two magnetic tapes, are carried by respective rotary disks. The rotary disks are mounted on a single shaft, and the latter is rotated by a single drum motor.
    Type: Grant
    Filed: August 27, 1985
    Date of Patent: July 7, 1987
    Assignee: Pioneer Electronic Corporation
    Inventor: Hiroshi Yokota
  • Patent number: 4668263
    Abstract: A rod-in-tube method for producing a glass preform for use in the fabrication of an optical fiber, which comprises steps of inserting a glass rod as a core material in a glass tube as a cladding material, fusing and closing one end of the cladding material, filling a gap between the core and cladding materials with an atmosphere containing at least one gaseous halogen-containing compound and then heating the core and cladding materials at a temperature not lower than 1,900.degree. C. to collapse the gap between them and to fuse them together, from which glass preform, an optical fiber with low attenuation of light transmission is fabricated.
    Type: Grant
    Filed: November 4, 1985
    Date of Patent: May 26, 1987
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Hiroshi Yokota, Gotaro Tanaka, Hiroo Kanamori, Futoshi Mizutani, Toshio Danzuka
  • Patent number: 4653852
    Abstract: A multi core optical fiber made of quartz glass comprising at least two cores the centers of which are arranged substantially on one line. The distances between the centers of the adjacent cores are substantially the same in the longitudinal direction. A first cladding covers the cores and the second cladding covers the first cladding and has a larger refractive index than the first one. The fiber has improved mechanical strength and low cross-talk even if the distance between the adjacent cores is short.
    Type: Grant
    Filed: January 3, 1985
    Date of Patent: March 31, 1987
    Assignees: Sumitomo Electric Industries, Ltd, Nippon Telegraph and Telephone Public Corporation
    Inventors: Shuzo Suzuki, Ichiro Ogasawara, Hiroshi Yokota, Shim Sumida
  • Patent number: 4647262
    Abstract: Disclosed here is a fastener made of synthetic resin or the like for removably fixing a plurality of plate-like members, said fastener comprising a female member and a male member, said female member comprising a base plate formed with a hole into which a shaft portion of said male member is inserted, a stopper of substantially W-shape in section provided with a pair of leg portions extending from a lower surface of said base plate along an edge portion of said hole and a link portion of substantially inversed U-shape in section for connecting said leg portions, and a pair of engagement projections inwardly projecting from an inner periphery of said hole; said male member comprising a head portion, a shaft portion provided with a neck portion downwardly extending from said head portion and a flat portion downwardly extending from said neck portion and adapted to be inserted into said hole, said flat portion being provided with a pair of stop projections and shoulders adapted to be engaged with said engagement
    Type: Grant
    Filed: February 13, 1986
    Date of Patent: March 3, 1987
    Assignees: Toyota Jidosha Kabushiki Kaisha, Daiwa Kasei Kogyo Kabushiki Kaisha
    Inventor: Hiroshi Yokota
  • Patent number: 4545801
    Abstract: A device is disclosed for supplying a glass raw material gas in the form of the mixed gas consisting of the glass raw material gas and the carrier gas to a vapor deposition device for producing a preform of an optical fiber, the supply device including a secondary raw material container having a pressurizable interior and provided adjacent to a main raw material container. The bottoms, or areas near the bottoms, of the two containers are interconnected via a pipe including at a mid portion thereof a switching valve and a device for adjusting the flow rate of the raw material liquid between the two containers. Liquid level detectors are provided in one or both containers to maintain the constant volume of the liquid raw material so as to provide a constant state inside the main raw material container. The operation of this device can easily be entirely automated.
    Type: Grant
    Filed: February 6, 1984
    Date of Patent: October 8, 1985
    Assignees: Sumitomo Electric Industries, Ltd., Nippon Telegraph & Telephone Public Corporation
    Inventors: Tetsuo Miyajiri, Toshimi Habasaki, Hiroshi Yokota, Tamio Tsurita, Motohiro Nakahara
  • Patent number: 4419116
    Abstract: A process and apparatus for producing an optical fiber preform by oxidizing a gaseous glass forming material with a flame from a burner and depositing the resulting soot in a rod form are described, wherein two signal beams, supplied by splitting a light beam, are projected in a direction normal to the direction in which the preform grows and are directed into the space between the burner and the deposition face of the preform, and they are positioned so that one beam partially contacts the deposition face of the preform, while the other beam is directed to pass between the burner and the deposition face, and the distance between the burner and the deposition face is controlled such that the ratio of the intensity of the two beams passing through the space between the burner and the deposition face is held constant.
    Type: Grant
    Filed: December 11, 1981
    Date of Patent: December 6, 1983
    Assignees: Nippon Telegraph and Telephone Public Corporation, Sumitomo Electric Industries Limited
    Inventors: Motohiro Nakahara, Naoki Yoshioka, Hiroshi Yokota, Tetsuo Miyajiri, Minoru Watanabe
  • Patent number: 4414008
    Abstract: A process for producing a porous optical fiber preform by hydrolyzing a gaseous glass forming material with a flame from an oxyhydrogen burner and depositing the resulting soot in a rod form in a muffle furnace is described, wherein the muffle furnace is supplied with a gas other than that from the oxyhydrogen burner, and said gas is maintained at a constant temperature.
    Type: Grant
    Filed: December 11, 1981
    Date of Patent: November 8, 1983
    Assignees: Nippon Telegraph & Telephone Public Corporation, Sumitono Electric Inds., Ltd.
    Inventors: Takao Edahiro, Tetsuo Miyajiri, Hiroshi Yokota, Toru Kuwahara