Patents by Inventor Akira Hirano

Akira Hirano 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).

  • Publication number: 20210043804
    Abstract: To improve a wall plug efficiency in a nitride semiconductor light-emitting element for extracting ultraviolet light emitted from an active layer toward an n-type nitride semiconductor layer side to outside of the element.
    Type: Application
    Filed: February 14, 2018
    Publication date: February 11, 2021
    Applicant: Soko Kagaku Co., Ltd.
    Inventors: Akira HIRANO, Yosuke NAGASAWA, Shigefusa CHICHIBU, Kazunobu KOJIMA
  • Publication number: 20210028857
    Abstract: There is provided an optical transmission system in which a plurality of optical transmission and reception apparatuses perform 1-to-N transmission and reception of optical signals (N is an integer equal to or greater than 1), the optical transmission system being configured to select a communication condition that includes at least a modulation scheme or a baud rate and is a communication condition when each of the optical transmission and reception apparatuses performs transmission and reception in accordance with a transmission line condition that is between any one first optical transmission and reception apparatus and each of second optical transmission and reception apparatuses, which are N grounds, other than the first optical transmission and reception apparatus.
    Type: Application
    Filed: March 1, 2019
    Publication date: January 28, 2021
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Fumikazu INUZUKA, Shokei KOBAYASHI, Akira HIRANO, Wataru KAWAKAMI, Tetsuro INUI, Seiki KUWABARA, Kei KITAMURA, Takafumi TANAKA, Takuya ODA, Hideki NISHIZAWA, Seiji OKAMOTO
  • Publication number: 20210013963
    Abstract: A state estimating device includes a pre-processing unit and an estimating unit. The pre-processing unit acquires data representing at one or more of a phase of a signal transmitted from a transmission unit of a transmission device and received at a reception unit of another transmission device via a transmission path, a reception strength, a reception quality, a voltage after conversion into an electric signal, and a signal processing parameter used in reception processing, and processes the acquired data into feature data to be used for state estimation. The estimating unit estimates a state of the transmission path, an abnormal state of the transmission unit, or an abnormal state of the reception unit, on the basis of the feature data.
    Type: Application
    Filed: February 13, 2019
    Publication date: January 14, 2021
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Seiki KUWABARA, Wataru KAWAKAMI, Hideki NISHIZAWA, Seiji OKAMOTO, Akira HIRANO, Shokei KOBAYASHI, Tetsuro INUI, Takuya ODA, Fumikazu INUZUKA, Takafumi TANAKA
  • Publication number: 20200406682
    Abstract: An axle structure is provided with an axle housing for internally passing an axle shaft having wheels connected to both left and right ends thereof, and a drive motor unit. The axle housing includes a large diameter housing center portion having a recessed portion which is recessed from an opening portion on a front surface side toward a rear surface side, and small diameter hollow shaft portions connected as a left and right pair to both sides of the housing center portion. The drive motor unit is fitted into the recessed portion and is bolted to the axle housing by means of tightening bolts.
    Type: Application
    Filed: March 8, 2019
    Publication date: December 31, 2020
    Inventors: Kazunori OGAWA, Akira HIRANO
  • Publication number: 20200373463
    Abstract: A template includes a sapphire substrate with a (0001) plane or a plane inclined by a predetermined angle with respect to the (0001) plane as a main surface, and an AlN layer composed of AlN crystals having an epitaxial crystal orientation relationship with the main surface directly formed on the main surface of the sapphire substrate. In the template, an average particle diameter of the AlN crystals of the AlN layer at a thickness of 20 nm from the main surface is 100 nm or less.
    Type: Application
    Filed: September 29, 2017
    Publication date: November 26, 2020
    Applicant: Soko Kagaku Co., Ltd.
    Inventors: Akira HIRANO, Yosuke NAGASAWA
  • Publication number: 20200357953
    Abstract: The nitride semiconductor light-emitting element comprises a light-emitting element structure portion having a plurality of nitride semiconductor layers including at least an n-type layer, an active layer and a p-type layer. The active layer has a quantum well structure comprising at least one well layer composed of a GaN-based semiconductor. In the well layer, the shortest distance between a first surface on the n-type layer side and a second surface on the p-type layer side varies in an orthogonal plane to the layering direction of the nitride semiconductor layers, and the peak emission wavelength of light emitted from the light-emitting element structure portion is shorter than 354 nm.
    Type: Application
    Filed: November 22, 2017
    Publication date: November 12, 2020
    Applicant: Soko Kagaku Co., Ltd.
    Inventors: Akira HIRANO, Yosuke NAGASAWA
  • Patent number: 10823989
    Abstract: A control unit of a bias control circuit performs a loop process that fixes a second bias voltage and iterates a process of recording a pair of a first candidate bias voltage and a second candidate bias voltage that are a first bias voltage when optical power of a multi-level QAM signal output by an optical modulator is controlled so that the optical power converges to a value in the vicinity of the maximum value or the minimum value before and after a third bias voltage is increased or decreased by a half-wave voltage while changing the second bias voltage within a predetermined range. The control unit calculates the difference between the first candidate bias voltage and the second candidate bias voltage for each of a plurality of recorded pairs and determines a value between first candidate bias voltage and the second candidate bias voltage of a pair selected on the basis of the calculated difference as the value of the first bias voltage.
    Type: Grant
    Filed: July 12, 2018
    Date of Patent: November 3, 2020
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Hiroto Kawakami, Shoichiro Kuwahara, Akira Hirano
  • Publication number: 20200321491
    Abstract: Provided is an ultraviolet light emitting device having high quality and high reliability that prevents deterioration in electrical characteristics caused by a photochemical reaction of a non-bonding amorphous fluororesin, decomposition or the like of the amorphous fluororesin, and peeling off of the amorphous fluororesin. A nitride semiconductor ultraviolet light emitting device 1 includes a base 30, a nitride semiconductor ultraviolet light emitting element flip-chip mounted on the base 30, and an amorphous fluororesin 40 that is in direct contact with the nitride semiconductor ultraviolet light emitting element for covering. The nitride semiconductor ultraviolet light emitting element includes a sapphire substrate 11, a plurality of AlGaN-based semiconductor layers 12 laminated on the main surface of the sapphire substrate 11, an n-electrode 13, and a p-electrode 14.
    Type: Application
    Filed: February 27, 2017
    Publication date: October 8, 2020
    Applicants: Soko Kagaku Co., Ltd., AGC INC.
    Inventors: Akira HIRANO, Kiho YAMADA, Ko AOSAKI
  • Publication number: 20200274040
    Abstract: The ultraviolet light-emitting device includes a base, a nitride semiconductor ultraviolet light-emitting element flip-chip mounted on the base, and a lens for sealing a nitride semiconductor ultraviolet light-emitting element to focus or diffuse light emitted from the nitride semiconductor ultraviolet light-emitting device. The lens is composed of an amorphous fluororesin in which a structural unit of a polymer or copolymer has a fluorine-containing aliphatic cyclic structure and a terminal functional group is a perfluoroalkyl group, and a density of the amorphous fluororesin is higher than 2.11 g/cm3.
    Type: Application
    Filed: November 2, 2017
    Publication date: August 27, 2020
    Applicants: Soko Kagaku Co., Ltd., AGC INC.
    Inventors: Akira HIRANO, Yosuke NAGASAWA, Masamichi IPPOMMATSU, Ko AOSAKI, Yuki SUEHARA, Yoshihiko SAKANE
  • Patent number: 10742354
    Abstract: An optical receiver includes: a first calculation unit that obtains a log likelihood ratio for each M-dimension (M is a natural number), based on a received signal; and a second calculation unit that obtains a log likelihood ratio of an N dimensional symbol (N is a natural number), based on the log likelihood ratio for each M-dimension.
    Type: Grant
    Filed: June 20, 2017
    Date of Patent: August 11, 2020
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Masanori Nakamura, Mitsuteru Yoshida, Akira Hirano
  • Patent number: 10686520
    Abstract: A transmission quality estimation system includes, three or more nodes and a transmission quality estimation device configured to estimate, transmission quality. A multi-core fiber having a plurality of cores, the multi-core fiber being used in at least a partial segment of a connection between the nodes. A node of the nodes includes a core connection unit configured to drop, add or relay light transmitted from, to or to each of to the plurality of cores of the multi-core fiber. The transmission quality estimation device includes an estimation unit configured to estimate transmission quality between the nodes on the basis of a transmission quality measurement light dropped by the core connection unit.
    Type: Grant
    Filed: November 22, 2016
    Date of Patent: June 16, 2020
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Takuya Oda, Tetsuro Inui, Akira Hirano, Wataru Imajuku, Shoukei Kobayashi, Takafumi Tanaka, Yutaka Miyamoto, Hidehiko Takara
  • Publication number: 20200168775
    Abstract: A light-emitting device 1 comprises a base 30, a nitride semiconductor light-emitting element 10 flip-chip mounted on the base 30, and an amorphous fluororesin sealing the nitride semiconductor light-emitting element 10. The light-emitting device 1 comprises a deformation-prevention layer 60 for preventing a shape change of an amorphous fluororesin by heat treatment after shipment of the light-emitting device 1, and the deformation-prevention layer 60 is formed of a layer in which a thermosetting resin or an ultraviolet curing resin is cured, and the cured layer directly covers the surface of the amorphous fluororesin.
    Type: Application
    Filed: August 30, 2017
    Publication date: May 28, 2020
    Applicants: Soko Kagaku Co., Ltd., AGC INC.
    Inventors: Akira HIRANO, Yosuke NAGASAWA, Masamichi IPPOMMATSU, Ko AOSAKI, Yuki SUEHARA, Yoshihiko SAKANE
  • Patent number: 10643849
    Abstract: A manufacturing method of a nitride semiconductor ultraviolet light-emitting element having a peak emission wavelength of 285 nm or shorter comprises a first step of forming an n-type semiconductor layer composed of an n-type AlXGa1-XN-based semiconductor (1?X?0.5) on an upper surface of an underlying portion including a sapphire substrate, a second step of forming, above the n-type semiconductor layer, an active layer that includes a light-emitting layer composed of an AlYGa1-YN-based semiconductor (X>Y>0) and that is composed of an AlGaN-based semiconductor as a whole, and a third step of forming a p-type semiconductor layer composed of a p-type AlZGa1-ZN-based semiconductor (1?Z>Y) above the active layer. In the manufacturing method, a growth temperature at the second step is higher than 1200° C. and equal to or higher than a growth temperature at the first step.
    Type: Grant
    Filed: November 8, 2017
    Date of Patent: May 5, 2020
    Assignee: SOKO KAGAKU CO., LTD.
    Inventors: Akira Hirano, Yosuke Nagasawa, Shigefusa Chichibu, Kazunobu Kojima
  • Publication number: 20200133035
    Abstract: A control unit of a bias control circuit performs a loop process that fixes a second bias voltage and iterates a process of recording a pair of a first candidate bias voltage and a second candidate bias voltage that are a first bias voltage when optical power of a multi-level QAM signal output by an optical modulator is controlled so that the optical power converges to a value in the vicinity of the maximum value or the minimum value before and after a third bias voltage is increased or decreased by a half-wave voltage while changing the second bias voltage within a predetermined range. The control unit calculates the difference between the first candidate bias voltage and the second candidate bias voltage for each of a plurality of recorded pairs and determines a value between first candidate bias voltage and the second candidate bias voltage of a pair selected on the basis of the calculated difference as the value of the first bias voltage.
    Type: Application
    Filed: July 12, 2018
    Publication date: April 30, 2020
    Applicant: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Hiroto KAWAKAMI, Shoichiro KUWAHARA, Akira HIRANO
  • Patent number: 10637568
    Abstract: A transmission quality estimation system includes, three or more nodes and a transmission quality estimation device configured to estimate, transmission quality. A multi-core fiber having a plurality of cores, the multi-core fiber being used in at least a partial segment of a connection between the nodes. A node of the nodes includes a core connection unit configured to drop, add or relay light transmitted from, to or to each of to the plurality of cores of the multi-core fiber. The transmission quality estimation device includes an estimation unit configured to estimate transmission quality between the nodes on the basis of a transmission quality measurement light dropped by the core connection unit.
    Type: Grant
    Filed: November 22, 2016
    Date of Patent: April 28, 2020
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Takuya Oda, Tetsuro Inui, Akira Hirano, Wataru Imajuku, Shoukei Kobayashi, Takafumi Tanaka, Yutaka Miyamoto, Hidehiko Takara
  • Patent number: 10615868
    Abstract: A communication system which includes: three or more nodes; a multi-core fiber having a plurality of cores, the multi-core fiber being used in at least a partial segment of a connection between the nodes; a detection signal output unit configured to output a fault detection signal transmitted by the core provided in the multi-core fiber configured to connect together the nodes; and a fault detection unit configured to determine whether a fault has occurred between the nodes on the basis of a detection result of the fault detection signal.
    Type: Grant
    Filed: November 22, 2016
    Date of Patent: April 7, 2020
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Takuya Oda, Tetsuro Inui, Akira Hirano, Wataru Imajuku, Shoukei Kobayashi, Takafumi Tanaka, Yutaka Miyamoto, Hidehiko Takara
  • Patent number: 10587472
    Abstract: Accommodation design for wavelength and sub-? paths in a communication network is performed. If sub-? path accommodation is possible according to search for a wavelength path present in a single-hop logical route, the accommodation in the wavelength path is executed. If sub-? path accommodation is possible according to search for a wavelength path present in a multi-hop logical route, a logical route is selected based on the wavelength path and the sub-? path is accommodated in the wavelength path. Additionally, each physical route suitable for the sub-? path accommodation is searched for. If the route can accommodate a wavelength path set in a single-hop logical route by available wavelength allocation, the sub-? path is accommodated in the wavelength path. Furthermore, routes in consideration of overlapping of nodes, pipelines, and links and operation rate are selected based on information about the start and end nodes of each of redundant routes.
    Type: Grant
    Filed: September 14, 2017
    Date of Patent: March 10, 2020
    Assignee: Nippon Telegraph And Telephone Corporation
    Inventors: Akihiro Kadohata, Akira Hirano, Atsushi Watanabe, Fumikazu Inuzuka, Takafumi Tanaka
  • Patent number: 10527781
    Abstract: A communication system includes three or more nodes and a multi-core fiber having a plurality of cores, the multi-core fiber being used in at least a partial segment of the connection between the nodes is provided. One node of the nodes is connected to the multi-core fiber and includes a connector configured to add and drop a signal to and from an allocated core exclusively allocated from among the cores as a communication path between the one node and another node of the nodes and/or configured to relay a signal transmitted through another core of the cores allocated for communication between other nodes in the multi-core fiber connected to the one node, and a relative positional relationship between a connection position of the allocated core in which a signal is added or dropped in the connector and a connection position of another core in which a signal is relayed in the connector is the same for all of the nodes connected to the multi-core fiber.
    Type: Grant
    Filed: November 22, 2016
    Date of Patent: January 7, 2020
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Takuya Oda, Tetsuro Inui, Akira Hirano, Wataru Imajuku, Shoukei Kobayashi, Takafumi Tanaka, Yutaka Miyamoto, Hidehiko Takara
  • Patent number: 10511381
    Abstract: A communication system includes three or more nodes, and a multi-core fiber having a plurality of cores, the multi-core fiber being used in at least a partial segment of a connection between the nodes, wherein each of nodes includes: a fault information transmitting device configured to transmit fault information indicating that a fault has occurred in a communication path between one node and another node of the nodes when it is detected that it is not possible to perform communication between the one node and the another node; and a fault location specifying device configured to specify a section between nodes in which a fault has occurred on the basis of the fault information received from the fault information transmitting device provided in each of the nodes.
    Type: Grant
    Filed: November 22, 2016
    Date of Patent: December 17, 2019
    Assignee: NIPPON TELEGRAPH AND TELEPHONE CORPORATION
    Inventors: Takuya Oda, Tetsuro Inui, Akira Hirano, Wataru Imajuku, Shoukei Kobayashi, Takafumi Tanaka, Yutaka Miyamoto, Hidehiko Takara
  • Patent number: 10505087
    Abstract: A nitride semiconductor ultraviolet light-emitting element 1 comprises a sapphire substrate 10 and an element structure part 20 formed on a main surface 101 of the substrate 10. In the substrate 10, in a first portion 110 extending from the main surface 101 by a first distance, a sectional area of a cross section parallel to the main surface 101 continuously increases with distance from the main surface 101, and in a second portion 120 extending from a side opposite to the main surface 101 by a second distance, a sectional area of a cross section parallel to the main surface 101 continuously increases with distance from the side opposite to the main surface 101. The sum of the first distance and the second distance is equal to or less than the thickness of the substrate 10.
    Type: Grant
    Filed: August 24, 2017
    Date of Patent: December 10, 2019
    Assignee: SOKO KAGAKU CO., LTD.
    Inventors: Akira Hirano, Yosuke Nagasawa