Patents by Inventor Takao Nakamura

Takao Nakamura 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: 7858963
    Abstract: In the nitride based semiconductor optical device LE1, the strained well layers 21 extend along a reference plane SR1 tilting at a tilt angle ? from the plane that is orthogonal to a reference axis extending in the direction of the c-axis. The tilt angle ? is in the range of greater than 59 degrees to less than 80 degrees or greater than 150 degrees to less than 180 degrees. A gallium nitride based semiconductor layer P is adjacent to a light-emitting layer SP? with a negative piezoelectric field and has a band gap larger than that of a barrier layer. The direction of the piezoelectric field in the well layer W3 is directed in a direction from the n-type layer to the p-type layer, and the piezoelectric field in the gallium nitride based semiconductor layer P is directed in a direction from the p-type layer to the n-type layer. Consequently, the valence band, not the conduction band, has a dip at the interface between the light-emitting layer SP? and the gallium nitride based semiconductor layer P.
    Type: Grant
    Filed: April 1, 2010
    Date of Patent: December 28, 2010
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Masaki Ueno, Yohei Enya, Takashi Kyono, Katsushi Akita, Yusuke Yoshizumi, Takamichi Sumitomo, Takao Nakamura
  • Patent number: 7860270
    Abstract: A method for embedding a watermark into digital data by independently changing real and imaginary number components of the coefficient values of a complex watermark coefficient matrix using a key, performing a discrete Fourier inverse transform on the sequence matrix of the changed watermark and generating a watermark pattern, adding like tiling the water mark pattern to the original image, and generating an embedded image. A watermark detection method includes separating a block from an arbitrary position on the detected object image, performing a discrete Fourier transform on the block and obtaining a sequence matrix, generating position information for a component which is to be detected and is specified by the key, detecting a position marker sequence by calculating a phase difference of a sequence by a parallel displacement, for the position information, extracting offset information, and detecting the embedded watermark from the detected object image.
    Type: Grant
    Filed: November 13, 2009
    Date of Patent: December 28, 2010
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Takao Nakamura, Hiroshi Ogawa, Atsuki Tomioka, Youichi Takashima
  • Patent number: 7859007
    Abstract: To provide a light-emitting device using a nitride semiconductor which can attain high-power light emission by highly efficient light emission and a manufacturing method thereof, the light-emitting device includes a GaN substrate and a light-emitting layer including an InAlGaN quaternary alloy on a side of a first main surface of GaN substrate.
    Type: Grant
    Filed: August 11, 2004
    Date of Patent: December 28, 2010
    Assignees: Sumitomo Electric Industries, Ltd., RIKEN
    Inventors: Hideki Hirayama, Katsushi Akita, Takao Nakamura
  • Publication number: 20100322276
    Abstract: Provided is a group-III nitride semiconductor laser device with a laser cavity allowing for a low threshold current, on a semipolar surface of a support base in which the c-axis of a hexagonal group-III nitride is tilted toward the m-axis. First and second fractured faces 27, 29 to form the laser cavity intersect with an m-n plane. The group-III nitride semiconductor laser device 11 has a laser waveguide extending in a direction of an intersecting line between the m-n plane and the semipolar surface 17a. For this reason, it is feasible to make use of emission by a band transition enabling the low threshold current. In a laser structure 13, a first surface 13a is opposite to a second surface 13b. The first and second fractured faces 27, 29 extend from an edge 13c of the first surface 13a to an edge 13d of the second surface 13b. The fractured faces are not formed by dry etching and are different from conventionally-employed cleaved facets such as c-planes, m-planes, or a-planes.
    Type: Application
    Filed: July 27, 2010
    Publication date: December 23, 2010
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Yusuke YOSHIZUMI, Yohei ENYA, Takashi KYONO, Masahiro ADACHI, Katsushi AKITA, Masaki UENO, Takamichi SUMITOMO, Shinji TOKUYAMA, Koji KATAYAMA, Takao NAKAMURA, Takatoshi IKEGAMI
  • Patent number: 7851821
    Abstract: A group III nitride semiconductor device having a gallium nitride based semiconductor film with an excellent surface morphology is provided. A group III nitride optical semiconductor device 11a includes a group III nitride semiconductor supporting base 13, a GaN based semiconductor region 15, an active layer active layer 17, and a GaN semiconductor region 19. The primary surface 13a of the group III nitride semiconductor supporting base 13 is not any polar plane, and forms a finite angle with a reference plane Sc that is orthogonal to a reference axis Cx extending in the direction of a c-axis of the group III nitride semiconductor. The GaN based semiconductor region 15 is grown on the semipolar primary surface 13a. A GaN based semiconductor layer 21 of the GaN based semiconductor region 15 is, for example, an n-type GaN based semiconductor, and the n-type GaN based semiconductor is doped with silicon.
    Type: Grant
    Filed: February 26, 2010
    Date of Patent: December 14, 2010
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Takashi Kyono, Yusuke Yoshizumi, Yohei Enya, Katsushi Akita, Masaki Ueno, Takamichi Sumitomo, Takao Nakamura
  • Patent number: 7851243
    Abstract: In the nitride based semiconductor optical device LE1, the strained well layers 21 extend along a reference plane SR1 tilting at a tilt angle ? from the plane that is orthogonal to a reference axis extending in the direction of the c-axis. The tilt angle ? is in the range of greater than 59 degrees to less than 80 degrees or greater than 150 degrees to less than 180 degrees. A gallium nitride based semiconductor layer P is adjacent to a light-emitting layer SP? with a negative piezoelectric field and has a band gap larger than that of a barrier layer. The direction of the piezoelectric field in the well layer W3 is directed in a direction from the n-type layer to the p-type layer, and the piezoelectric field in the gallium nitride based semiconductor layer P is directed in a direction from the p-type layer to the n-type layer. Consequently, the valence band, not the conduction band, has a dip at the interface between the light-emitting layer SP? and the gallium nitride based semiconductor layer P.
    Type: Grant
    Filed: August 6, 2010
    Date of Patent: December 14, 2010
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Masaki Ueno, Yohei Enya, Takashi Kyono, Katsushi Akita, Yusuke Yoshizumi, Takamichi Sumitomo, Takao Nakamura
  • Publication number: 20100297784
    Abstract: In the nitride based semiconductor optical device LE1, the strained well layers 21 extend along a reference plane SR1 tilting at a tilt angle ? from the plane that is orthogonal to a reference axis extending in the direction of the c-axis. The tilt angle ? is in the range of greater than 59 degrees to less than 80 degrees or greater than 150 degrees to less than 180 degrees. A gallium nitride based semiconductor layer P is adjacent to a light-emitting layer SP? with a negative piezoelectric field and has a band gap larger than that of a barrier layer. The direction of the piezoelectric field in the well layer W3 is directed in a direction from the n-type layer to the p-type layer, and the piezoelectric field in the gallium nitride based semiconductor layer P is directed in a direction from the p-type layer to the n-type layer. Consequently, the valence band, not the conduction band, has a dip at the interface between the light-emitting layer SP? and the gallium nitride based semiconductor layer P.
    Type: Application
    Filed: August 6, 2010
    Publication date: November 25, 2010
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Masaki UENO, Yohei ENYA, Takashi KYONO, Katsushi AKITA, Yusuke YOSHIZUMI, Takamichi SUMITOMO, Takao NAKAMURA
  • Publication number: 20100276663
    Abstract: In a GaN based semiconductor optical device 11a, the primary surface 13a of the substrate 13 tilts at a tilting angle toward an m-axis direction of the first GaN based semiconductor with respect to a reference axis “Cx” extending in a direction of a c-axis of the first GaN based semiconductor, and the tilting angle is 63 degrees or more, and is less than 80 degrees. The GaN based semiconductor epitaxial region 15 is provided on the primary surface 13a. On the GaN based semiconductor epitaxial region 15, an active layer 17 is provided. The active layer 17 includes one semiconductor epitaxial layer 19. The semiconductor epitaxial layer 19 is composed of InGaN. The thickness direction of the semiconductor epitaxial layer 19 tilts with respect to the reference axis “Cx.” The reference axis “Cx” extends in the direction of the [0001] axis. This structure provides the GaN based semiconductor optical device that can reduces decrease in light emission characteristics due to the indium segregation.
    Type: Application
    Filed: June 18, 2010
    Publication date: November 4, 2010
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Yohei ENYA, Yusuke YOSHIZUMI, Masaki UENO, Katsushi AKITA, Takashi KYONO, Takamichi SUMITOMO, Takao NAKAMURA
  • Publication number: 20100279495
    Abstract: A method of forming a p-type gallium nitride based semiconductor without activation annealing is provided, and the method can provide a gallium nitride based semiconductor doped with a p-type dopant. A GaN semiconductor region 17 containing a p-type dopant is formed on a supporting base 13 in a reactor 10. An organometallic source and ammonia are supplied to the reactor 10 to grow the GaN semiconductor layer 17 on a GaN semiconductor layer 15. The GaN semiconductor is doped with a p-type dopant. Examples of the p-type dopant include magnesium. After the GaN semiconductor regions 15 and 17 are grown, an atmosphere 19 containing at least one of monomethylamine and monoethylamine is prepared in the reactor 10. After the atmosphere 19 is prepared, a substrate temperature is decreased from the growth temperature of the GaN semiconductor region 17. When the substrate temperature is lowered to room temperature after this film formation, a p-type GaN semiconductor 17a and an epitaxial wafer E has been fabricated.
    Type: Application
    Filed: April 30, 2010
    Publication date: November 4, 2010
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Masaki UENO, Yusuke YOSHIZUMI, Takao NAKAMURA
  • Patent number: 7817818
    Abstract: A method for embedding a watermark into digital data, when the watermark is to be embedded in a digital image, independently changes real number components and imaginary number components of each of coefficient values of a complex watermark coefficient matrix using key, from the watermark to be embedded in the digital image, a step for performing a discrete Fourier inverse transform on the sequence matrix of the changed watermark and generating a watermark pattern; and a step for adding like tiling the water mark pattern to the original image, and generating an embedded image.
    Type: Grant
    Filed: April 25, 2006
    Date of Patent: October 19, 2010
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Takao Nakamura, Hiroshi Ogawa, Atsuki Tomioka, Youichi Takashima
  • Publication number: 20100230690
    Abstract: A group III nitride semiconductor device having a gallium nitride based semiconductor film with an excellent surface morphology is provided. A group III nitride optical semiconductor device 11a includes a group III nitride semiconductor supporting base 13, a GaN based semiconductor region 15, an active layer active layer 17, and a GaN semiconductor region 19. The primary surface 13a of the group III nitride semiconductor supporting base 13 is not any polar plane, and forms a finite angle with a reference plane Sc that is orthogonal to a reference axis Cx extending in the direction of a c-axis of the group III nitride semiconductor. The GaN based semiconductor region 15 is grown on the semipolar primary surface 13a. A GaN based semiconductor layer 21 of the GaN based semiconductor region 15 is, for example, an n-type GaN based semiconductor, and the n-type GaN based semiconductor is doped with silicon.
    Type: Application
    Filed: February 26, 2010
    Publication date: September 16, 2010
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Takashi KYONO, Yusuke YOSHIZUMI, Yohei ENYA, Katsushi AKITA, Masaki UENO, Takamichi SUMITOMO, Takao NAKAMURA
  • Patent number: 7792323
    Abstract: A method for embedding a watermark into digital data, when the watermark is to be embedded in a digital image, independently changes real number components and imaginary number components of each of coefficient values of a complex watermark coefficient matrix using key, from the watermark to be embedded in the digital image, a step for performing a discrete Fourier inverse transform on the sequence matrix of the changed watermark and generating a watermark pattern; and a step for adding like tiling the water mark pattern to the original image, and generating an embedded image.
    Type: Grant
    Filed: April 25, 2006
    Date of Patent: September 7, 2010
    Assignee: Nippon Telegraph and Telephone Corporation
    Inventors: Takao Nakamura, Hiroshi Ogawa, Atsuki Tomioka, Youichi Takashima
  • Publication number: 20100213439
    Abstract: In the nitride based semiconductor optical device LE1, the strained well layers 21 extend along a reference plane SR1 tilting at a tilt angle ? from the plane that is orthogonal to a reference axis extending in the direction of the c-axis. The tilt angle ? is in the range of greater than 59 degrees to less than 80 degrees or greater than 150 degrees to less than 180 degrees. A gallium nitride based semiconductor layer P is adjacent to a light-emitting layer SP? with a negative piezoelectric field and has a band gap larger than that of a barrier layer. The direction of the piezoelectric field in the well layer W3 is directed in a direction from the n-type layer to the p-type layer, and the piezoelectric field in the gallium nitride based semiconductor layer P is directed in a direction from the p-type layer to the n-type layer. Consequently, the valence band, not the conduction band, has a dip at the interface between the light-emitting layer SP? and the gallium nitride based semiconductor layer P.
    Type: Application
    Filed: April 1, 2010
    Publication date: August 26, 2010
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Masaki Ueno, Yohei Enya, Takashi Kyono, Katsushi Akita, Yusuke Yoshizumi, Takamichi Sumitomo, Takao Nakamura
  • Publication number: 20100207138
    Abstract: Group III nitride semiconductor crystals of a size appropriate for semiconductor devices and methods for manufacturing the same, Group III nitride semiconductor devices and methods for manufacturing the same, and light-emitting appliances. A method of manufacturing a Group III nitride semiconductor crystal includes a process of growing at least one Group III nitride semiconductor crystal substrate on a starting substrate, a process of growing at least one Group III nitride semiconductor crystal layer on the Group III nitride semiconductor crystal substrate, and a process of separating a Group III nitride semiconductor crystal, constituted by the Group III nitride semiconductor crystal substrate and the Group III nitride semiconductor crystal layer, from the starting substrate, and is characterized in that the Group III nitride semiconductor crystal is 10 ?m or more but 600 ?m or less in thickness, and is 0.2 mm or more but 50 mm or less in width.
    Type: Application
    Filed: April 26, 2010
    Publication date: August 19, 2010
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Seiji Nakahata, Hideaki Nakahata, Koji Uematsu, Makoto Kiyama, Youichi Nagai, Takao Nakamura
  • Publication number: 20100184236
    Abstract: The present inventors conducted a similarity search of the amino acid sequence of known G protein-coupled receptor proteins in GenBank, and obtained a novel human GPCR gene “BG37”, cDNA containing the ORF of the gene was cloned and its nucleotide sequence was determined. Moreover, novel GPCR “BG37” genes from mouse and rat were isolated. Use of the novel GPCR of the present invention enables screening of ligands, compounds inhibiting the binding to a ligand, and candidate compounds of pharmaceuticals which can regulate signal transduction from the “BG37” receptor.
    Type: Application
    Filed: March 3, 2010
    Publication date: July 22, 2010
    Applicant: Banyu Pharmaceuticals Co., Ltd.
    Inventors: TAKAHARU MARUYAMA, Takao Nakamura, Hiraku Itadani, Ken-Ichi Tanaka
  • Patent number: 7732236
    Abstract: The invention provides Group III nitride semiconductor crystals of a size appropriate for semiconductor devices and methods for manufacturing the same, Group III nitride semiconductor devices and methods for manufacturing the same, and light-emitting appliances. A method of manufacturing a Group III nitride semiconductor crystal includes a process of growing at least one Group III nitride semiconductor crystal substrate on a starting substrate, a process of growing at least one Group III nitride semiconductor crystal layer on the Group III nitride semiconductor crystal substrate, and a process of separating a Group III nitride semiconductor crystal, constituted by the Group III nitride semiconductor crystal substrate and the Group III nitride semiconductor crystal layer, from the starting substrate, and is characterized in that the Group III nitride semiconductor crystal is 10 ?m or more but 600 ?m or less in thickness, and is 0.2 mm or more but 50 mm or less in width.
    Type: Grant
    Filed: May 13, 2005
    Date of Patent: June 8, 2010
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Seiji Nakahata, Hideaki Nakahata, Koji Uematsu, Makoto Kiyama, Youichi Nagai, Takao Nakamura
  • Publication number: 20100131768
    Abstract: A method for embedding digital watermark data in digital data contents includes the steps of obtaining a frequency coefficient of block data of digital data contents, obtaining a complexity of the block data, obtaining an amount of transformation of the frequency coefficient from the complexity and the digital watermark data, and embedding the digital watermark data by transforming the frequency coefficient. In addition, a method for reading digital watermark data includes the steps of calculating a probability of reading ‘1’ or ‘0’ in a read bit sequence by using a test method on the basis of binary distribution, determining the presence or absence of digital watermark data according to the probability, and reconstituting digital watermark data. Another method includes the steps of performing soft decision in code theory by assigning weights to the digital watermark sequence with a weighting function, and reconstituting digital watermark data.
    Type: Application
    Filed: November 9, 2009
    Publication date: May 27, 2010
    Inventors: Hiroshi Ogawa, Takao Nakamura, Atsuki Tomioka, Youichi Takashima
  • Patent number: 7723046
    Abstract: The present inventors conducted a similarity search of the amino acid sequence of known G protein-coupled receptor proteins in GenBank, and obtained a novel human GPCR gene “BG37”. cDNA containing the ORF of the gene was cloned and its nucleotide sequence was determined. Moreover, novel GPCR “BG37” genes from mouse and rat were isolated. Use of the novel GPCR of the present invention enables screening of ligands, compounds inhibiting the binding to a ligand, and candidate compounds of pharmaceuticals which can regulate signal transduction from the “BG37” receptor.
    Type: Grant
    Filed: February 8, 2007
    Date of Patent: May 25, 2010
    Assignee: Banyu Pharmaceutical Co., Ltd.
    Inventors: Takaharu Maruyama, Takao Nakamura, Haraku Itadani, Ken-ichi Tanaka
  • Publication number: 20100119106
    Abstract: A method for embedding a watermark into digital data, when the watermark is to be embedded in a digital image, independently changes real number components and imaginary number components of each of coefficient values of a complex watermark coefficient matrix using key, from the watermark to be embedded in the digital image, a step for performing a discrete Fourier inverse transform on the sequence matrix of the changed watermark and generating a watermark pattern; and a step for adding like tiling the water mark pattern to the original image, and generating an embedded image.
    Type: Application
    Filed: November 13, 2009
    Publication date: May 13, 2010
    Inventors: Takao Nakamura, Hiroshi Ogawa, Atsuki Tomioka, Youichi Takashima
  • Publication number: 20100102297
    Abstract: A source gas flows through a flow channel 23 of a metal-organic vapor phase epitaxy reactor 21. The source gas is fed in a direction across a main surface 25a of a susceptor 25. GaN substrates 27a to 27c are placed on the susceptor main surface 25a. An off-angle monotonically varies on a line segment extending from one point on the edges of the main surfaces of the gallium nitride substrates 27a to 27c to another point on the edges. The orientations of the GaN substrates 27a to 27c are represented by the orientations of the orientation flats. By placing the plurality of gallium nitride substrates 27a to 27c on the susceptors 25 of the metal-organic vapor phase epitaxy reactor 21 in these orientations, the influence of the off-angle distribution can be reduced by using the influence originated from the flow of the source gas.
    Type: Application
    Filed: February 20, 2008
    Publication date: April 29, 2010
    Applicant: SUMITOMO ELECTRIC INDUSTRIES, LTD.
    Inventors: Yusuke Yoshizumi, Masaki Ueno, Takao Nakamura